Filter by type:





Sort by date:

1.  A hybrid tracking system for image-guided spine surgery using a tracked mobile C-arm: a phantom study

P. Ghobadi, A. Ahmadian, H. saberi, M.R. Ay, M. Addolghafar and K. Amini
Book Chapter
Turk J Elec Eng & Comp Sci, 2017, Vol. 25, pp 434-448.

2.  New approach for calibration of pixelated scintillation detectors of intraoperative gamma cameras

Afshin Akbarzadeh, Valiallah Saba, Mohammad Reza Ay
Peer-reviewed Journal Publication
Iranian Journal of Nuclear Medicine and Molecular Imaging, 2017, Vol. 25, No. 1, pp 34-42.

3.  Development and characterization of a compact hand-held gamma probe system, SURGEOGUIDE, based on NEMA NU3-2004 standards

S. Kaviani, N. Zeraatkar,S. Sajedi, N. Gorjizadeh, M.H. Farahani, P. Ghafarian,G. El Fakhri, H. Sabete and M.R. Ay
Peer-reviewed Journal Publication

4.  How Crystal Configuration Affects the Position Detection Accuracy in Pixelated Molecular SPECT Imaging Systems?

H. Mahani, G. Raisali, A. Kamali, and M.R. Ay
Peer-reviewed Journal Publication
Nuclear Science and Techniques, 2016, in press

5.  Collimator-Detector Response Compensation in Molecular SPECT Reconstruction using STIR Framework?

H. Mahani, G. Raisali, A. Kamali, and M.R. Ay
Peer-reviewed Journal Publication
Iranian Journal of Nuclear Medicine and Molecular Imaging, 2016, in press

6.  MR-guided attenuation map for prostate PET-MRI: an intensity and morphologic-based segmentation approach for generating a five-class attenuation map in pelvic region

M. Shandiz, H. Saligeh Rad, P. Ghafarian, M. Bakhshaysh Karam and M.R. Ay
Peer-reviewed Journal Publication
Ann Nucl Med. 2016 Sep 28

Abstract:

PURPOSE:

Prostate imaging is one of the major application of hybrid PET/MRI systems. Inaccurate attenuation maps (µ-maps) derived by direct segmentation (SEG) in which the cortical bone is ignored and the volume of the air in cavities is underestimated is the main challenge of commercial PET/MRI systems for the quantitative analysis of the pelvic region. The present study considered the cortical bone and air cavity along with soft tissue, fat, and background air in the µ-map of the pelvic region using a method based on SEG. The proposed method uses a dedicated imaging technique that increases the contrast between regions and a hybrid segmentation method to classify MR images based on intensity and morphologic characteristics of tissues, such as symmetry and similarity of bony structures.

PROCEDURES:

Ten healthy volunteers underwent MRI and ultra-low dose CT imaging. The dedicated MR imaging technique uses the short echo time (STE) based on the conventional sequencing implemented on a clinical 1.5T MRI scanner. The generation of a µ-map comprises the following steps: (1) bias field correction; (2) hybrid segmentation (HSEG), including segmenting images into clusters of cortical bone-air, soft tissue, and fat using spatial fuzzy c-means (SFCM), and separation of cortical bone and internal air cavities using morphologic characteristics; (3) the active contour approach for the separation of background air; and (4) the generation of a five-class μ-map for cortical bone, internal air cavity, soft tissue, fat tissue, and background air. Validation was done by comparison with segmented CT images.

RESULTS:

The Dice and sensitivity metrics of cortical bone structures and internal air cavities were 72 ± 11 and 66 ± 13 and 73 ± 10 and 68 ± 20 %, respectively. High correlation was observed between CT and HSEG-based µ-maps (R 2 > 0.99) and the corresponding sinograms (R 2 > 0.98).

CONCLUSIONS:

Currently, pelvis µ-maps provided by the current PET/MRI systems and the ultra-short echo time and atlas-based methods tend to be inaccurate. The proposed method acceptably generated a five-class μ-map using only one image.

KEYWORDS:

MRI-base attenuation correction; Morphologic characteristics-based segmentation; PET/MRI; Prostate imaging; STE pulse sequence

7.  Design and development of a dedicated portable gamma camera system for intra-operative imaging

S. Kaviani, N. Zeraatkar, S. Sajedi, A. Akbarzadeh, N. Gorjizadeh, M. H. Farahani, B. Teimourian, P. Ghafarian, H. Sabet and M.R. Ay
Peer-reviewed Journal Publication
Phys Med. 2016 Jul;32(7):889-97. doi: 10.1016/j.ejmp.2016.06.004. Epub 2016 Jun 23

Abstract

PURPOSE:

We developed a high performance portable gamma camera platform dedicated to identification of sentinel lymph nodes (SLNs) and radio-guided surgery for cancer patients. In this work, we present the performance characteristics of SURGEOSIGHT-I, the first version of this platform that can intra-operatively provide high-resolution images of the surveyed areas.

METHODS:

At the heart of this camera, there is a 43×43 array of pixelated sodium-activated cesium iodide (CsI(Na)) scintillation crystal with 1×1mm(2) pixel size and 5mm thickness coupled to a Hamamatsu H8500 flat-panel multi-anode (64 channels) photomultiplier tube. The probe is equipped with a hexagonal parallel-hole lead collimator with 1.2mm holes. The detector, collimator, and the associated front-end electronics are encapsulated in a common housing referred to as head.

RESULTS:

Our results show a count rate of ∼41kcps for 20% count loss. The extrinsic energy resolution was measured as 20.6% at 140keV. The spatial resolution and the sensitivity of the system on the collimator surface was measured as 2.2mm and 142cps/MBq, respectively. In addition, the integral and differential uniformity, after uniformity correction, in useful field-of-view (UFOV) were measured 4.5% and 4.6%, respectively.

CONCLUSIONS:

This system can be used for a number of clinical applications including SLN biopsy and radiopharmaceutical-guided surgery.

Keywords:

Sentinel lymph node (SLN), Lymphoscintigraphy, SURGEOSIGHT-I, Breast cancer, Intra-operative gamma camera

8.  Single STE-MR Acquisition in MR-Based Attenuation Correction of Brain PET Imaging Employing a Fully Automated and Reproducible Level-Set Segmentation Approach

A. Fathi, M.R. Ay, S. Arfaei, and P. Khateri and H. Salighe Rad
Peer-reviewed Journal Publication
Molecular Imaging & Biology, 2016

9.  Design and Assessment of a Novel SPECT System for Desktop Open-Gantry Imaging of Small Animals: a Monte Carlo Study

N. Zeraatkar, M. H. Farahani, S. Sarkar, A. Rahmim and M.R. Ay
Peer-reviewed Journal Publication
Med Phys. 2016 May;43(5):2581. doi: 10.1118/1.4947127

Abstract

PURPOSE:

Given increasing efforts in biomedical research utilizing molecular imaging methods, development of dedicated high-performance small-animal SPECT systems has been growing rapidly in the last decade. In the present work, we propose and assess an alternative concept for SPECT imaging enabling desktop open-gantry imaging of small animals.

METHODS:

The system, PERSPECT, consists of an imaging desk, with a set of tilted detector and pinhole collimator placed beneath it. The object to be imaged is simply placed on the desk. Monte Carlo (MC) and analytical simulations were utilized to accurately model and evaluate the proposed concept and design. Furthermore, a dedicated image reconstruction algorithm, finite-aperture-based circular projections (FABCP), was developed and validated for the system, enabling more accurate modeling of the system and higher quality reconstructed images. Image quality was quantified as a function of different tilt angles in the acquisition and number of iterations in the reconstruction algorithm. Furthermore, more complex phantoms including Derenzo, Defrise, and mouse whole body were simulated and studied.

RESULTS:

The sensitivity of the PERSPECT was 207 cps/MBq. It was quantitatively demonstrated that for a tilt angle of 30°, comparable image qualities were obtained in terms of normalized squared error, contrast, uniformity, noise, and spatial resolution measurements, the latter at ∼0.6 mm. Furthermore, quantitative analyses demonstrated that 3 iterations of FABCP image reconstruction (16 subsets/iteration) led to optimally reconstructed images.

CONCLUSIONS:

The PERSPECT, using a novel imaging protocol, can achieve comparable image quality performance in comparison with a conventional pinhole SPECT with the same configuration. The dedicated FABCP algorithm, which was developed for reconstruction of data from the PERSPECT system, can produce high quality images for small-animal imaging via accurate modeling of the system as incorporated in the forward- and back-projection steps. Meanwhile, the developed MC model and the analytical simulator of the system can be applied for further studies on development and evaluation of the system.

10.  Is Grid Therapy Useful for all Tumors and Every Grid Block Design?

S. Gholami, H. Nedaie, F. Longo, M. R. Ay, S. Wright and A. S. Meigooni
Peer-reviewed Journal Publication
J Appl Clin Med Phys. 2016 Mar 8;17(2):6015

Abstract

Grid therapy is a treatment technique that has been introduced for patients with advanced bulky tumors. The purpose of this study is to investigate the effect of the radiation sensitivity of the tumors and the design of the grid blocks on the clinical response of grid therapy. The Monte Carlo simulation technique is used to determine the dose distribution through a grid block that was used for a Varian 2100C linear accelerator. From the simulated dose profiles, the therapeutic ratio (TR) and the equivalent uniform dose (EUD) for different types of tumors with respect to their radiation sensitivities were calculated. These calculations were performed using the linear quadratic (LQ) and the Hug-Kellerer (H-K) models. The results of these calculations have been validated by comparison with the clinical responses of 232 patients from different publications, who were treated with grid therapy. These published results for different tumor types were used to examine the correlation between tumor radiosensitivity and the clinical response of grid therapy. Moreover, the influence of grid design on their clinical responses was investigated by using Monte Carlo simulations of grid blocks with different hole diameters and different center-to-center spacing. The results of the theoretical models and clinical data indicated higher clinical responses for the grid therapy on the patients with more radioresistant tumors. The differences between TR values for radioresistant cells and radiosensitive cells at 20 Gy and 10 Gy doses were up to 50% and 30%, respectively. Interestingly, the differences between the TR values with LQ model and H-K model were less than 4%. Moreover, the results from the Monte Carlo studies showed that grid blocks with a hole diameters of 1.0 cm and 1.25 cm may lead to about 19% higher TR relative to the grids with hole diameters smaller than 1.0 cm or larger than 1.25 cm (with 95% confidence interval). In sum-mary, the results of this study indicate that grid therapy is more effective for tumors with radioresistant characteristics than radiosensitive tumors.

11.  Reduction of Respiratory Induced Artefact in PET/CT Images using TOF Reconstruction

R. Sharif Pour, P. Ghafarian, A. Doroudinia, M. Bakhshayesh Karam and M. R. Ay
Published Abstract
ACNM 2016

Abstract

Objectives:

The aim of this study was to investigate the effect of time-of-flight (TOF) and point-spread function (PSF) for quantitative and qualitative PET/CT image analysis in relation to decrease respiratory artifact in diaphragmatic region.

Methods:

29 patients with uptake time 61±2 min and injection of 327.5 MBq (range 261–350 MBq) 18F-FDG were scanned with Discovery 690 GE PET/CT scanner, equipped with 64-slice CT. All of the lesions were in the diaphragmatic region including: the lung lower lobes, liver and stomach in patients with extended white band artefact. For quantitative measurement NEMA phantom were also utilized. The PET images were retrospectively reconstructed using HD (Fully 3D Iterative Reconstruction)+PSF and TOF+ PSF algorithm with various iterations, subsets and post smoothing filters. A semi-quantitative analysis was performed using SUVmax and SUVmean with 50% threshold. We also considered image quality using coefficient of variance (COV) in the liver in clinical study, the signal-to-noise ratio (SNR) and contrast to background measurements in each lesions. The PET/CT images reviewed by two expert physicians.

Results:

In the phantom study, SUVmean illustrated the more convenient value in related to SUVmax when TOF+PSF algorithm applied with increase of post filter from 4.4 mm to 6.4mm. In clinical study, the COV was decreased 7.4%±1.3% when TOF+PSF were compared with non-TOF image. The SUVmax trend to higher value with relative difference 11.3% (range: 0.5%–25.1%) when TOF and non-TOF images were evaluated. It was interesting that using appropriate TOF reconstruction parameter increased the SNR up 65.6% (Range: 7.0%–194.7%). The combination of TOF and PSF decreased the lesion size on PET images 33.0%, 25.7% and 24.5% in sagital, coronal and axial view respectively when compared with HD+PSF algorithm. According to balance among the SNR, contrast, noise and visual assessment, the optimal images were obtained with TOF+PSF with FWHM between 5.2 to 6.4 mm.

Conclusion:

A little overestimation in SUVmax versus to SUV mean 50% was observed, when PSF with combination of either VPHD or TOF was used. TOF with PSF improved white band artifact in diaphragmatic region remarkably, increased lesion delectability, and altered lesion size in PET images. It is noteworthy that the variation in SUV and lesion size is strongly dependent to the proximity of the lesions to the artefact region and it is highly recommended that to attain optimal image quality, combination of low iteration number and utilizing appropriate Gaussian filter is necessary because noise and false positive findings could be dominant with small-FWHM post filter.

12.  Hybrid Imaging, PET/CT, in HANDBOOK OF SMALL ANIMAL IMAGING, Preclinical Imaging, Therapy, and Applications

M.R. Ay and N. Ghazanfari
Book Chapter
George C. Kagadis et al. , Editors. 2016, Tylor & Francis Books, Inc.
Mohammad Reza Ay and Nafiseh Ghazanfari
Introduction to Combining MRI with PET

13.  Acceptance Test of the first Hospital Cyclotron for Production of PET tracers in Iran

P. Ghafarian, S. M. Khamesi1, M. R. Golrokh Nodehi and M. R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 518

14.  An alternate mathematical modeling of image formation, and framework for performance analysis of positioning algorithms in the scintillation camera

S. Hosseini, M. H. Farahani and M. R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 103

15.  Can Pacemaker and ICD degrade CT-Based Attenuation Corrected cardiac SPECT images?

Z. Etemadi, A. Bitaran Rajabi, H. Malek, P. Ghafarian, N. Zeraatkar and M.R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 132

16.  Correction of Metal Artefacts Induced from Pacemaker and ICD Leads in CT-Based Attenuation Correction of Cardiac SPECT data

M. R. Ay, Z. Etemadi, A. Bitarafan-Rajabi, H. Malek, N. Zeraatkar and P. Ghafarian
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 522

17.  Design, modeling and performance evaluation of a small animal Micro-CT scanner: A Monte Carlo study

S. Nezhaddehghani1, S. Sarkar, and M. R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 97

18.  Generating a four-class attenuation map for MR-based attenuation correction of PET data in pelvis region using an automatic segmentation protocol

H. Saligheh Rad, M. Shirin Shandiz, P. Ghafarian, M. H. Arabi, M. Bakhshayeshkaram, N. Shafiei and M. R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 201

19.  Generation of 4-Class Attenuation Map for MRI Based Attenuation Correction of PET Data in the Head Area Using a Novel Combination of STE/DIXON-MRI and FCM Clustering

P. Khateri, H. Saligheh Rad, A. Homayoun Jafari, A. Fathi, A. Akbarzadeh, M. Shojae Moghadam, A. Aryan, P. Ghafarian and M.R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 371

20.  Impact of Point spread function modeling on tumor quantification in clinical PET/CT imaging

S. Ahangari1, P. Ghafarian, M. Bakhshayeshkaram and M. R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 133

21.  Measurement of Photon and Neutron Dose Distribution in Cyclotron Bunker During F18 and N13 Production

P. Ghafarian, S. M. Khamesi, M. R. Golrokh Nodehi and M.R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 606

22.  Monte Carlo Simulation of X-ray Spectra in Computed Tomography Scanner using GATE

M. R. Ay, S. Nezhaddehghani1, and S. Sarkar
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 331

23.  Optimal Pixelated Crystal for a Molecular SPECT Scanner: A GATE Monte Carlo Study

M. R. Ay, H. Mahani, G. Raisali, and A. Kamali-Asl
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 200

24.  Spinning Knife-Edge Slit-Hole: a Novel Collimation for High-Sensitivity Molecular SPECT

H. Mahani, G. Raisali, A. Kamali-Asl and M.R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 200

25.  The Impact of time of flight algorithm and PSF modeling on standard uptake value in clinical PET/CT imaging

M. Shekari, P. Ghafarian, M. Bakhshayeshkaram and M. R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p 132

26.  TLD Measurement of Absorbed Dose of Workers in PET/CT Department

P. Ghafarian, S. Zargan, A. Shabestani Monfared, A. Sharafi, M. Bakhshayeshkaram and M.R. Ay
Published Abstract
World Congress on Medical Physics & Biomedical Engineering, 7-12 June 2015, Toronto, Canada, p109

27.  An optimal Grid block design for spatially fractionated radiation therapy

S. Gholami S , H. Nedaie, F. Longo, M. R. Ay, AS. Meigooni
Published Abstract
ESTRO 2015

28.  Generation of a Four-Class Attenuation Map for MRI-Based Attenuation Correction of PET Data in the Head Area Using a Novel Combination of STE/Dixon-MRI and FCM Clustering

P. Khateri, H. Saligheh Rad, A. H. Jafari, A. Fathi Kazerooni, A. Akbarzadeh, M. Shojae Moghadam, A. Aryan, P. Ghafarian, M. R. Ay
Peer-reviewed Journal Publication
Mol Imaging Biol. 2015 Dec;17(6):884-92. doi: 10.1007/s11307-015-0849-1

Abstract

PURPOSE:

The aim of this study is to generate a four-class magnetic resonance imaging (MRI)-based attenuation map (μ-map) for attenuation correction of positron emission tomography (PET) data of the head area using a novel combination of short echo time (STE)/Dixon-MRI and a dedicated image segmentation method.

PROCEDURES:

MR images of the head area were acquired using STE and two-point Dixon sequences. μ-maps were derived from MRI images based on a fuzzy C-means (FCM) clustering method along with morphologic operations. Quantitative assessment was performed to evaluate generated MRI-based μ-maps compared to X-ray computed tomography (CT)-based μ-maps.

RESULTS:

The voxel-by-voxel comparison of MR-based and CT-based segmentation results yielded an average of more than 95 % for accuracy and specificity in the cortical bone, soft tissue, and air region. MRI-based μ-maps show a high correlation with those derived from CT scans (R (2) > 0.95).

CONCLUSIONS:

Results indicate that STE/Dixon-MRI data in combination with FCM-based segmentation yields precise MR-based μ-maps for PET attenuation correction in hybrid PET/MRI systems.

KEYWORDS:

Attenuation correction; Attenuation map; FCM technique; PET/MRI; STE pulse sequence

29.  Impact of the Radiation Sensitivity of Tumor and Geometric Design of the GRID Block On the Clinical Response of Grid Therapy

S. Gholami, AS. Meigooni, H. Nedaie, F. Longo M. R. Ay
Published Abstract
Med. Phys. 42, 3440 (2015); http://dx.doi.org/10.1118/1.4924823

Abstract

Purpose:

The spatially fractionated radiation therapy (Grid therapy) is a novel technique that has been recently introduced for treatments of the patients with advanced bulky tumors. The purpose of this study is to investigate the effect of the radiation sensitivity of tumor and Grid block design on the clinical response of the Grid therapy.

Methods:

The Geant4 toolkit is used to simulate a Varian2100C linear accelerator with the block-based Grid. The dose profile has been utilized to calculate the Therapeutic Ratio (TR) and Equivalent Uniform Dose (EUD) for different types of tumors. These calculations were performed with respect to their radiation sensitivities using Linear Quadratic model (LQ). Clinical responses of few hundred patients from different publications that were treated with Grid therapy, have been used to validate correlation between tumor radiation sensitivity and clinical response of Grid therapy. Moreover, the influence of Grid design on clinical response of this radiation technique was investigated with using Monte Carlo simulation of a Grid block with different hole-diameters of 0.5 cm, 0.75 cm, 1.25 cm, and 1.5 cm. The Geometrical Sparing Factor (GSF) was considered to compare the results from different Grid designs.

Results:

The higher clinical response of Grid therapy for more radio-resistant tumors was confirmed in both theoretical assumptions and clinical outcomes. In addition, the results indicate that the Grid hole diameter have more effect on increasing the TR in comparison with the hole center-to-center distance effect. From this Monte Carlo study, a Grid design with the hole diameter between 1.25 cm and 1.5 cm with GSF value of 0.90 is recommended.

Conclusion:

Grid Therapy is more effective for more radio-resistant tumors.The optimum results of the Grid therapy depend on selection of the appropriate Grid design.This study is a first step toward clarifying some important aspects in a clinical response of spatially fractionated radiation therapy.

30.  Monte Carlo Calculation of Neutron Doses to Organs of a Female Undergoing A Pelvic 18 MV Irradiation

M. Zabihzadeh, S.R. Mahdavi, M.R. Ay and Z. Shakarami
Peer-reviewed Journal Publication
Biomedical & Pharmacology Journal, 2015, Vol. 8, pp 65-71

31.  Monte Carlo-based Assessment of the Trade-off between Spatial Resolution, Field-of-View and Scattered Radiation in the Variable Resolution X-ray CT Scanner

H. Arabi, A.R. Kamali Asl, M. R. Ay and H. Zaidi
Peer-reviewed Journal Publication
Phys Med, 2015, Vol. 31, pp 510-516

32.  Optimizing Image Reconstruction Parameters in Time of Flight PET/CT Imaging: a Phantom Study

M. Shekari, P. Ghafarian, S. Ahangari, H. Ghadiri, M. Bakhshayeshkaram and M.R. Ay
Peer-reviewed Journal Publication
2015, Vol. 2, No. 3, pp 146-154

33.  The Effects of Backscattered Radiation into Beam Monitor Chamber: Study of 6 and 18 MV Conventional and Removed Flattening Filter Clinical Accelerator

M. Zabihzadeh, S.R. Mahdavi, M.R. Ay and Z. Shakarami
Peer-reviewed Journal Publication
BIOSCIENCES BIOTECHNOLOGY RESEARCH ASIA, 2015, Vol. 12, pp 25-36

34.  The Impact of Point Spread Function Modeling on Scan Duration in PET Imaging

S. Ahangari, P. Ghafarian, M. Shekari, H. Ghadiri, M. Bakhshayeshkaram and M.R. Ay
Peer-reviewed Journal Publication
Frontiers in Biomedical Technologies, 2015, Vol. 2, No. 3, pp 137-145

35.  Design and development of small fieldof view portable gamma camera for localization of sentinel lymph nodes

V. Moji, N. Zaratkar, S. Sajedi, A. Akbarzadeh, B. Timourian, M.H. Farahani and M. R. Ay
Published Abstract
18th Iranian Conference of Nuclear Medicine, Tehran, Iran, 12-14 November 2104, pp. 70

36.  Development of a hybrid small animal SPECT/CT scanner:a Monte Carlo study

S. Nerzhaddehghani, S. Sarkar and M.R. Ay
Published Abstract
18th Iranian Conference of Nuclear Medicine, Tehran, Iran, 12-14 November 2104, pp. 71

37.  Experimental measurement of absorbed dose using TLD for radiation workers in PET/CT department

S. Zargan, A. Monfared, P. Ghafarian, A. K. Sharafi, M. Bakhshayesh karam and M.R. Ay
Published Abstract
18th Iranian Conference of Nuclear Medicine, Tehran, Iran, 12-14 November 2104, pp. 157

38.  Monte Carlo-based characterization of HiReSPECT scanner: a dedicatd small animal SPECT imaging system

H. Mahani, G. Raisali, A. Kamali asl and M.R. Ay
Published Abstract
18th Iranian Conference of Nuclear Medicine, Tehran, Iran, 12-14 November 2104, pp. 73

39.  Optimizing the acquisition time in whole body PET/CT imaging

S. Ahanghari, P. Ghafarian, M. Sherkari, M. Bakhshayesh karam and M.R. Ay
Published Abstract
18th Iranian Conference of Nuclear Medicine, Tehran, Iran, 12-14 November 2104, pp. 75

40.  Performance evaluation of surgical gamma probe for sentinel lymph node localization based on NMA NU3-2004 standard

N. Gorjizadeh, S. Farzanehfar, A. Kaviani, N. Zeraatkar, M. H. Farhani, S. Sajesi and M.R. Ay
Published Abstract
18th Iranian Conference of Nuclear Medicine, Tehran, Iran, 12-14 November 2104, pp. 77

41.  Quantification of inter-crystal scatter and penetration in HiReSPCT: a dedicated small animal SPCT imaging systm

H. Mahani, G. Raisali, A. Kamali asl and M.R. Ay
Published Abstract
18th Iranian Conference of Nuclear Medicine, Tehran, Iran, 12-14 November 2104, pp. 78

42.  A Fully Automated and Reproducible Level-set Segmentation Approach for Generation of MR-Based Attenuation Correction Map of PET Images in the Brain Employing Single STE-MR Imaging Modality

Fathi, M. H. Arbabi, M.R. Ay and H. Saligheh Rad
Published Abstract
PSMR 2014 MR-PET Workshop, Kos Island, Greece, 19-21 May 2014, EJNMMI Physics 2014, 1(Suppl 1):A48

43.  A hybrid method for generation of attenuation map for MR-based attenuation correction of PET data in prostate PET/MR imaging

M. Shirin Shandiz, M. H. Arabi, P. Ghafarian, M. Bakhshayesh Karam , H. Saligheh Rad and M.R. Ay
Published Abstract
PSMR 2014 MR-PET Workshop, Kos Island, Greece, 19-21 May 2014, EJNMMI Physics 2014, 1(Suppl 1):A77

44.  MR-Based Attenuation Map Generation in Short-TE MR Images of the Head Employing Spatial Fuzzy C-Means Clustering Approach

M. H. Arabi, A. Fathi, P. Khateri, M.R. Ay and H. Saligheh Rad
Published Abstract
PSMR 2014 MR-PET Workshop, Kos Island, Greece, 19-21 May 2014, EJNMMI Physics 2014, 1(Suppl 1):A49

45.  A Novel Segmentation Approach for Implementation of MRAC in Head PET/MRI Employing Short-TE MRI and 2-Point Dixon Method in a Fuzzy C-Means Framework

P. Khateri, H. Saligeh Rad, A.H. Jafari and M.R. Ay
Peer-reviewed Journal Publication
Nuclear Instrumentation Methods in Physics Research A, 2014, Vol. 734, No. 8, pp 171-174

46.  Classification of bones from MR images in torso PET-MR imaging using a statistical shape model

M. R. Ay, A. Akbarzadeh, A. Ahmadian and H. Zaidi
Peer-reviewed Journal Publication
Nuclear. Instrumentation Methods in Physics Research A, 2014, Vol. 734, pp 196-200

Abstract

There have been exclusive features for hybrid PET/MRI systems in comparison with its PET/CT counterpart in terms of reduction of radiation exposure, improved soft-tissue contrast and truly simultaneous and multi-parametric imaging capabilities. However, quantitative imaging on PET/MR is challenged by attenuation of annihilation photons through their pathway. The correction for photon attenuation requires the availability of patient-specific attenuation map, which accounts for the spatial distribution of attenuation coefficients of biological tissues. However, the lack of information on electron density in the MR signal poses an inherent difficulty to the derivation of the attenuation map from MR images. In other words, the MR signal correlates with proton densities and tissue relaxation properties, rather than with electron density and, as such, it is not directly related to attenuation coefficients. In order to derive the attenuation map from MR images at 511 keV, various strategies have been proposed and implemented on prototype and commercial PET/MR systems. Segmentation-based methods generate an attenuation map by classification of T1-weighted or high resolution Dixon MR sequences followed by assignment of predefined attenuation coefficients to various tissue types. Intensity-based segmentation approaches fail to include bones in the attenuation map since the segmentation of bones from conventional MR sequences is a difficult task. Most MR-guided attenuation correction techniques ignore bones owing to the inherent difficulties associated with bone segmentation unless specialized MR sequences such as ultra-short echo (UTE) sequence are utilized. In this work, we introduce a new technique based on statistical shape modeling to segment bones and generate a four-class attenuation map. Our segmentation approach requires a torso bone shape model based on principle component analysis (PCA). A CT-based training set including clearly segmented bones of the torso region of 20 clinical studies was designed. Using this training set, a bone atlas was trained taking advantage of PCA analysis. Our active shape segmentation technique uses the trained shape model to segment bones from user defined initial seed points. The segmentation algorithm was evaluated using 10 clinical datasets (aligned MR and CT pairs). The resulting attenuation maps were compared to corresponding attenuation maps derived from CT resulting in a mean relative difference less than 7%.

Keywords:

PET/MRI; MR bone segmentation; Attenuation correction; Whole-body imaging

47.  Derivation of attenuation map for attenuation correction of PET data in the presence of nanoparticulate contrast agents using spectral CT imaging

H. Ghadiri, MB Shiran, HR Soltanian-Zadeh, A. Rahmim, H. Zaidi and M.R. Ay
Peer-reviewed Journal Publication
Annals of Nuclear Medicine, 2014, Vol. 28, No. 6, pp 559-570

48.  Design and Development of a High Resolution Animal SPECT Scanner Dedicated for Rat and Mouse Imaging

S. Sajedi , N. Zeraatkar, V. Moji, M. H. Farahani, S. Sarkar, H. Arabi, B. Teymoorian, P. Ghafarian, A. Rahmim and M.R. Ay
Peer-reviewed Journal Publication
Nuclear. Instrumentation Methods in Physics Research A, 2014, Vol. 741, pp 169-176

49.  Experimental Evaluation of the Performance of HiReSPECT Scanner: a High-Resolution SPECT System for Small Animal Imaging

A. M. Pashazadeh, K. Tanha, F. Jafarian Dehkordi, M. Assadi, V. Moji , N. Zeraatkar and M.R. Ay
Peer-reviewed Journal Publication
Frontiers in Biomedical Technologies, 2014, Vol. 1, No. 3, pp 222-227

50.  How Gamma Camera’s Head-Tilts Affect Image Quality of a Nuclear Scintigram?

H. Mahani, A. Kamali-Asl, M.R. Ay
Peer-reviewed Journal Publication
Frontiers in Biomedical Technologies, 2014, Vol. 1, No. 4, pp 265-270

51.  Performance Evaluation of Newly Developed High Resolution Dual Head Animal SPECT System Based on NEMA NU2 2007 Standard

V. Moji, N. Zeraatkar, M.H. Farahani, M. Aghamiri, S. Sajedi, B. Teymorian, P. Ghafarian , S. Sarkar and M.R. Ay
Peer-reviewed Journal Publication
J Appl Clin Med Phys, 2014, Vol. 15, No. 6, pp 267-278

52.  Positron Emission Tomography: Physics, Instrumentation, Scanners and New Horizons

M.R. Ay and P. Geramifar
Book Chapter
2014, Royan Pazhoh, Inc., Tehran, Iran, ISBN-13: 9786007108543

53.  Quantification of PET and CT misalignment errors due to bulk motion in cardiac PET/CT imaging: Phantom and clinical studies

P. Ghafarian, M.R. Ay, A. Fard-Esfahani, A. Rahmim and H. Zaidi
Peer-reviewed Journal Publication
Frontiers in Biomedical Technologies, 2014, Vol. 1, No. 3, pp 159-167

54.  Resolution-Recovery-Embedded Image Reconstruction for a High-Resolution Animal SPECT System

N. Zeraatkar, S. Sajedi, M. H. Farahani, H. Arabi, S. Sarkar, P. Ghafarian, A. Rahmim and M.R. Ay
Peer-reviewed Journal Publication
Phys Med, 2014, Vol. 30, No. 7, pp 774-781

55.  The Influence of PET and CT Misalignment due to Respiratory Motion on the Cardiac PET/CT Imaging: a Simulation Study

P. Ghafarian, M.R. Ay
Peer-reviewed Journal Publication
Frontiers in Biomedical Technologies, 2014, Vol. 1, No. 4, pp 252-257

56.  Optical Flow Based Method for Generation of Virtual Average CT: A Simulation Study Using 4D XCAT Phantom

P. Geramifar, M. Shamsaie Zafarghandi and M.R. Ay
Published Abstract
European Association of Nuclear Medicine Annual Congress, 19-23 October 2013, Lyon, France. Eur J Nucl Med Mol, Vol 20, Issue 2

57.  Performance Evaluation of a Small Field of View Portable Gamma Camera for Localization of Sentinel Lymph Nodes

N. Gorjizadeh, N. Zeraatkar, A. Kaviani, S. Farzaneh far, M. H. Farahani, A. Akbarzadeh, S. Sajedi, B. Teimourian and M.R. Ay
Published Abstract
European Association of Nuclear Medicine Annual Congress, 19-23 October 2013, Lyon, France. Eur J Nucl Med Mol, Vol 20, Issue 2

58.  SURGEOGUIDE: a Gamma Probe for Localization of Sentinel Lymph Nodes

M.R. Ay, N. Zeraatkar, N. Gorjizadeh, S. Sajedi, H. Arabi, M. H. Farahani, B. Teimourian
Published Abstract
European Association of Nuclear Medicine Annual Congress, 19-23 October 2013, Lyon, France. Eur J Nucl Med Mol, Vol 20, Issue 2

59.  The Influence of Misalignment Artifact Due to Global and Respiratory Motion on Interpretation of Cardiac PET/CT Examination: Clinical and Phantom Studies

P. Ghafarian and M.R. Ay
Published Abstract
European Association of Nuclear Medicine Annual Congress, 19-23 October 2013, Lyon, France. Eur J Nucl Med Mol, , Vol 20, Issue 2

60.  Variation in Thoracic Lesions SUVmax as a Function of Respiratory Phase Based on the Optical Flow Motion Estimation: A Simulation Study Using 4D XCAT Phantom

P. Geramifar, M. Shamsaie Zafarghandi and M.R. Ay
Published Abstract
European Association of Nuclear Medicine Annual Congress, 19-23 October 2013, Lyon, France. Eur J Nucl Med Mol, Vol 20, Issue 2

61.  K-edge ratio method for identification of multiple nanoparticulate contrast agents by spectral CT imaging

H Ghadiri, M. R. Ay , M. B. Shiran, H. R. Soltanian-Zadeh and H Zaidi
Peer-reviewed Journal Publication
Br J Radiol. 2013 Sep; 86(1029): 20130308

62.  A fast and hardware mimicking analytic CT simulator

H Ghadiri, M B Shiran, H R Soltanian-Zadeh, A Rahmim and M R Ay
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Seoul, South Korea, 2013, pp 1-5

Abstract:

Different algorithms have been utilized for x-ray computed tomography (CT) simulation based on Monte Carlo technique, analytic calculation, or combination of them. Software packages based on Monte Carlo algorithm provide sophisticated calculations but the time consuming nature of them limits its applicability. Analytic calculation for CT simulation has been also evaluated in recent years. Due to ignoring basic physical processes, analytic methods have limited applications. In this study, a hardware mimicking algorithm has been developed to accurately model the CT imaging chain using analytic calculation. The model includes x-ray spectrum generation according to the pre-defined scanning protocol. The detector is designed to acquire the data either in integral or spectral modes. CT geometry can be used as parallel or fan beam with different sizes. Poisson noise model was applied to the acquired projection data. Varieties of projection-based computerized phantoms have been designed and implemented in the simulator. CT number and background noise of the simulated images have been compared with experimental data. On average, the relative difference between simulated and experimental HUs are 8.3%, 7.5%, and 8.0% for bone; 12.1%, 10.3%, and 7.8% for contrast agent; and 16.6%, 3.6%, and 5.2% for the background at 80 kVp/500 mAs, 120 kVp/250 mAs, and 140 kVp/125 mAs, respectively. The relative difference between simulated and experimental noise values vary between 2% to slightly less than 26%. For scanning and image generation with a computer equipped with Intel Core2 Quad CPU and 2.0 GB of RAM, the simulator takes about 32 seconds for generating a 512×512 single slice image when it is adjusted to acquire 900 projection angles with 20 mm slice thickness and 140kVp/200 mAs scanning protocol. The simulation time is independent of photon intensity.

63.  A Novel Segmentation Approach for Implementation of MRAC in Head and Neck PET/MRI Imaging Employing Short-TE MRI and 2-Point Dixon Method in Fuzzy C-Means Framework

P. Khateri, H. Salighe Rad, A.H. Jafari and M.R. Ay
Published Abstract
PSMR 2013 MR-PET Workshop, Jülich, Germany, 6-7 May –2013

64.  Classification of bones from MR images in torso PET-MR imaging using a statistical shape model

M.R. Ay, Akbarzadeh A, Ahmadian and Zaidi H
Published Abstract
PSMR 2013 MR-PET Workshop, Jülich, Germany, 6-7 May –2013

65.  A new energy mapping algorithm based on spectral CT images: application in PET/CT attenuation correction

H. Ghadiri, M.B. Shiran, H.R. Soltanian-Zadeh and M.R. Ay
Published Abstract
Iranian Congress of Nuclear Medicine, Shiraz, Iran, May 1-3, 2013

66.  Performance evaluation of HiReSPECT a dedicated animal SPECT system using modified NEMA standards

V.Moji, M. Aghamiri, H. Farahani, N. Zeratkar, S. Sajedi, B. Teymorian and M.R. Ay
Published Abstract
Iranian Congress of Nuclear Medicine, Shiraz, Iran, May 1-3, 2013

67.  Spatial Resolution and System Sensitivity in a Tilted-Head Planar-SPECT: a Monte Carlo Study

H. Mahani, A. R. Kamali-Asl, V. Moslemi, M.R. Ay
Published Abstract
Iranian Congress of Nuclear Medicine, Shiraz, Iran, May 1-3, 2013

68.  3D Prior Image Constrained Projection Completion for X-ray CT Metal Artifact Reduction

A. Mehranian, M. R. Ay, A. Rahmim and H. Zaidi
Peer-reviewed Journal Publication
IEEE Trans Nuclear Sciences, 2013, Vol. 60, No. 5, pp 3318-3332

69.  A novel non-linear recursive filter design for extracting high rate pulse features in nuclear medicine imaging and spectroscopy

S. Sajedi, A. Kamali Asl, M. R. Ay, M.H. Farahani and A. Rahmim
Peer-reviewed Journal Publication
Medical Engineers & Physics , 2013, Vol. 35, No.6, pp. 754-764

70.  An ordered-subsets proximal preconditioned gradient algorithm for edge-preserving PET image reconstruction

A. Mehranian, A. Rahmim, M. R. Ay, F. Kotasidis and H. Zaidi
Peer-reviewed Journal Publication
Medical Physics 2013, Vol. 40, No. 5, pp 052503-14

71.  EBT GHAFCROMIC film dosimetry in compensator-based intensity modulation radiation therapy

S. Vaezzadeh, M. Allahverdi, H. Nedaei, M. R. Ay, A. Shirazi and M. Yarahmadi
Peer-reviewed Journal Publication
Medical Dosimetry , 2013, Vol. 38, pp. 176-183

72.  Evaluation of whole-body MR to CT deformable image registration

A. Akbarzadeh, D. Gutierrez, A. Baskin, M. R. Ay, A. Ahmadian, N. Riahi Alam, K. Lövblad and H. Zaidi
Peer-reviewed Journal Publication
J Appl Clin Med Phys, 2013, Vol. 14, No. 4, pp 238-253

73.  Experimental assessment of the influence of beam hardening filters on image quality and patient dose in volumetric 64-slice x-ray CT scanners

M. R. Ay, A. Mehranian, A. Maleki, H. Ghadiri,P. Ghafarian and H. Zaidi
Peer-reviewed Journal Publication
Phys Med , 2013, Vol. 29, pp. 249-260

74.  MRI-guided attenuation correction in whole-body PET/MR: Assessment of the effect of bone attenuation

A. Akbarzadeh, M. R. Ay, A. Ahmadian, N. Riahi Alam and H. Zaidi
Peer-reviewed Journal Publication
Annals of Nuclear Medicine, 2013, Vol. 27, pp. 152-162

75.  Respiratory-Induced Errors in Tumor Quantification and Delineation in CT Attenuation Corrected PET Images: Effects of Tumor Size, Tumor Location and Respiratory Trace - A Simulation Study Using the 4D XCAT Phantom

P. Geramifar, M. Shamsaie Zafarghandi, P. Ghafarian, A. Rahmim and M. R. Ay
Peer-reviewed Journal Publication
Molecular Imaging & Biology, 2013, Vol. 15, No. 6, pp 655-665

76.  Smoothly Clipped Absolute Deviation (SCAD) Regularization for Compressed Sensing MRI Using an Augmented Lagrangian Scheme

A. Mehranian, H. Salighe Rad, A. Rahmim, M. R. Ay and H. Zaidi
Peer-reviewed Journal Publication
Magnetic Resonance Imaging, 2013, Vol. 31, No. 8, pp 1399-1411

77.  X-ray CT metal artifact reduction using wavelet domain L0 sparse regularization

A. Mehranian, M. R. Ay, A. Rahmim and H. Zaidi
Peer-reviewed Journal Publication
IEEE Trans Med Imaging, 2013, Vol. 32, No. 9, pp 1707-1722

78.  An Innovative Rotation-Based Iterative Resolution Recovery for HiReSPECT™: a Dedicated Small Animal SPECT System

N. Zeraatkar, M. H. Farahani, H. Arabi, S. Sarkar, S. Sajedi, N. Naderi, P. Ghafarian, A. Rahmim and M.R. Ay
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S386-S387

79.  Design and Development of a High Resolution Small Animal Imaging System for Mice and Rat

M.R. Ay , H. Arabi, M. H. Farahani, N. Zeraatkar, S. Sarkar, S. Sajed, N. Naderi and P. Ghafaian
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S441

80.  Determination of Attenuation Map at 511 keV Employing 3D Short Echo-Time MR Imaging in the Head Area: Application in MR-Based AC of PET data

P. Khareti, H. Salighe Rad, and M.R. Ay
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S369

81.  Digital signal processing unit for nuclear detection system

S. Sajedi, M.R. Ay, M. H. Farahani, N. Zeraatkar, H. Arabi, and N. Naderi
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S498

82.  Evaluation of the influence of respiratory motion misalignment between PET and CT data on diagnosis of heart defects using 4D XCAT phantom and STIR reconstruction

M. Sedighpoor, P. Ghafarian, A. Emami, M.R. Ay
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S515

83.  Quantification of the influence of misregistration between CT and SPECT images on the accuracy of CT-based attenuation correction of cardiac images in hybrid SPECT/CT systems

L. Saleki, A. Bitarafan-Rajabi, N. Yaghobi, B. Falahi, and M.R. Ay
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S518

84.  Standardized Uptake Value-Based Evaluations of Respiratory-Induced Errors in CTAC PET Images: A Simulation Study Using 4D XCAT Phantom

P. Geramifar, M. Shamsaie Zafarghandi, M.R. Ay
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S403

85.  SURGEOSIGHT-TM: An Intraoprative Hand Held Gamma Camera for Precise Localization of Sentine Lymph Nodes

M.R. Ay , H. Arabi, M. H. Farahani, N. Zeraatkar, S. Sarkar, S. Sajed, N. Naderi and P. Ghafaian
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S385

86.  The influence of crystal material and size on the performance of partial-rotating dual head small animal PET scanners: Quantitative evaluation using Monte Carlo modeling

N. Ghazanfari, M.R. Ay, S.Sarkar and G.Loudos
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S442

87.  The influence of resolution recovery during image reconstruction on quantitative brain SPECT imaging

A. Emami-Ardekani, F. Kalantari, H. Rajabi, M.R. Ay, A. Fard, M. Eftekhari
Published Abstract
European Association of Nuclear Medicine Annual Congress, 27-31 October 2012, Milan, Itly. Eur J Nucl Med Mol, S500

88.  Smoothly Clipped Absolute Deviation (SCAD) Regularization for Compressed Sensing MRI Using an Augmented Lagrangian Scheme

Mehranian A, H. Salighe Rad, M.R. Ay , Rahmim A, and Zaidi H
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Anaheim, CA, USA, 2012, pp 3646-3653

Abstract:

Compressed sensing (CS) in magnetic resonance imaging (MRI) enables the reconstruction of MR images from highly undersampled k-spaces, and thus substantial reduction of data acquisition time. In this context, edge-preserving and sparsity-promoting regularizers are used to exploit the prior knowledge that MR images are sparse or compressible in a given transform domain and thus to regulate the solution space. In this study, we introduce a new regularization scheme by iterative linearization of the non-convex clipped absolute deviation (SCAD) function in an augmented Lagrangian framework. The performance of the proposed regularization, which turned out to be an iteratively weighted total variation (TV) regularization, was evaluated using 2D phantom simulations and 3D retrospective undersampling of clinical MRI data by different sampling trajectories. It was demonstrated that the proposed regularization technique substantially outperforms conventional TV regularization, especially at reduced sampling rates.

89.  Generation of attenuation map for MR-based attenuation correction of PET data in the head area employing 3D short echo time MR imaging

P. Khareti, H. Salighe Rad, A. Fathi and M.R. Ay
Published Abstract
Proc. PSMR Conference, Isola de Elba, Italy 26-30 May , p. 70, 2012

90.  3D Calculation of Absorbed Dose for 131I Targeted Radiotherapy: A Monte Carlo Study

E. Saeedzadeh, S. Sarkar, A. Abbaspour Tehrani-Fard, M.R. Ay, H.R. Khosravi, G. Loudos
Peer-reviewed Journal Publication
Radiation Protection Dosimetry, 2012, 150, pp. 298-305

91.  3D TV-Based Compressed MR Image Reconstruction Using a Primal Dual Algorithm

A. Mehranian, H. S. Rad, M.R. Ay, and A. Rahmim
Published Abstract
Proc. Intl. Soc. Mag. Reson. Med., vol. 20, pp. 4228, 2012

92.  A novel energy mapping approach for CT-based attenuation correction in PET

B. Teimourian , M. R. Ay, M. Shamsaei-Zafarghandi, P. Ghafarian, H. Ghadiri and H. Zaidi
Peer-reviewed Journal Publication
Med Phys 2012, Vol. 39, No. 4, pp 2078-2089

93.  A proximal splitting algorithm for TV-regularized PET image reconstruction

A. Mehranian, A. Rahmim, and M.R. Ay
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 43, 2012

94.  An Ordered-Subsets Proximal Preconditioned Gradient Algorithm for Total Variation Regularized PET Image Reconstruction

Mehranian A, M.R. Ay, Rahmim A, and Zaidi H
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Anaheim, CA, USA, 2012, pp 3375-3382

95.  Development of a fully 3D image reconstruction for a pinhole animal SPECT

M. Khamesi, A. Kamali Asl, M. Masoudi, N. Zeraatkar, and M.R. Ay
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 122, 2012

96.  Development of image reconstruction code with collimator-detector response function compensation for a preclinical SPECT scanner

N. Zeraatkar, M. H. Farahani, H. Arabi, S. Sarkar, S. Sajedi, A. Rahmim, and M.R. Ay
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 36, 2012

97.  Generalized 4D AB-OSEM direct parametric imaging: application to PiB-PET

A. Rahmim, Y. Zhou, J. Price, J. Tang, L. Lu, M.R. Ay, G. Smith, V. Sossi, and D. Wong
Published Abstract
J. Nucl. Med., vol. 53 (suppl. 1): 313, 2012

98.  Generation of attenuation map for MR-based attenuation correction of PET data in the head area employing 3D short echo time MR imaging

P. Khateri, H. Saligeh Rad, A, Fathi and M.R. Ay
Peer-reviewed Journal Publication
Nuclear. Instrumentation Methods in Physics Research A, 2012, Vol. 702, No.21, pp. 133-136

99.  High resolution small animal SPECT: HiReSPECT for preclinical imaging

H. Arabi, M. H. Farahani, N. Zeraatkar, S. Sarkar, S. Sajedi, A. Rahmim, P. Ghafarian and M.R. Ay
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 93, 2012

100.  HiReSPECT an in house high resolution SPECT imaging system

M.R. Ay
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 10, 2012

101.  Impact of miscentering on patient dose and image noise in x-ray CT imaging: Phantom and clinical studies

M.A. Habibzadeh, M.R. Ay, A.R. Kamali Asl, H. Ghadiri and H. Zaidi H
Peer-reviewed Journal Publication
Phys Med Vol. 28, 2012, pp. 191-199

102.  Implementation of data acquisition board with digital signal processing capability for nuclear imaging and spectrometry devices

S. Sajedi, M. H. Farahani, H. Arabi, N. Zeraatkar, and M.R. Ay
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 39, 2012

103.  QCT technique optimization by dual energy CT

A. Emami, H. Ghadiri, P. Ghafarian and M.R. Ay
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 125, 2012

104.  Quantification of the influence of respiratory motion induced misalignment between PET and CT data on diagnosis of heart disease in cardiac PET/CT imaging

M. Sedigpoor, M.R. Ay, P. Ghafarian, P. Farnia
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 129, 2012

105.  Quantitative assessment of the influence of crystal material and size on the performance of rotating dual head small animal PET scanners: Monte Carlo modeling

N. Ghazanfari, S. Sarkar, G. Loudos, M.R. Ay
Peer-reviewed Journal Publication
Hellenic Journal of Nuclear Medicine, 2012, Vol. 15, No. 1, pp. 33-39

106.  The accuracy of dual energy mapping approach in CTAC in presence of low concentration of contract agent

H. Ghadiri, M.B. Shiran, H. Zaidi, H. Soltanian Zadeh and M.R. Ay
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 60, 2012

107.  The influence of opening angels and collimator material on the spatial resolution of pinhole collimator in animal SPECT imaging

M. Masoudi, A. Kamali Asl, M. Khamesi, H. Arabi and M.R. Ay
Published Abstract
Proc. Asia Oceania Congress of Nucl. Med. & Biology, vol. 20 (suppl. 1), p. 122, 2012

108.  The infuence of resolution recovery by using collimator detector response during 3D OSEM image reconstruction on 99mTc-ECD brain SPET images

F. Kalantari, H. Rajabi, M. R. Ay, A. Fard Esfahani, M. Eftekhari, B. Fallahi, A. Emami Ardekani
Peer-reviewed Journal Publication
Hellenic Journal of Nuclear Medicine, 2012, Vol. 15, No. 2, pp. 91-96

109.  A novel energy mapping approach in CT-based attenuation correction of PET data using multi-energy CT imaging

Ghadiri H, Shiran MB, M.R. Ay, Soltanian-Zadeh H and Zaidi H
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Valencia, Spain, 23-29 October 2011, p. 2510-2515

110.  A Novel Phantom for Accurate Performance Assessment of Bone Mineral Measurement Techniques: DEXA and QCT

A. Emami, H. Ghadiri, M.R. Ay, S. Akhlagpour, A. Eslami, P. Ghafarian and S. Taghizadeh
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Valencia, Spain, 23-29 October 2011, p. 3441-3445

111.  Characterization of scattered radiation profile in volumetric 64-slice x-ray CT scanner: A Monte Carlo study

Najafi Darmian A, M.R. Ay, Ghafarian P, Pouladian M, Shirazi A, Ghadiri H, Akbarzadeh A and Zaidi H
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Valencia, Spain, 23-29 October 2011, p. 2692–2696

112.  Generalized inter-frame and intra-frame motion correction in dynamic PET imaging

H. Mohy-ud-Din, N. Karakatsanis, C. Endres, M. R. Ay, D. F. Wong, and A. Rahmim
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Valencia, Spain, 23-29 October 2011, p. 3858-3862

113.  Impact of tissue classification on the accuracy of MR-based attenuation correction in PET-MRI

Akbarzadeh A, M.R. Ay, Ahmadian A, Riahi Alam N and Zaidi H
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Valencia, Spain, 23-29 October 2011, p. 2524–2530

114.  Metal artifact reduction in CT-based attenuation correction of PET using Sobolev sinogram restoration

Mehranian A, M.R. Ay, Rahmim A and Zaidi H
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Valencia, Spain, 23-29 October 2011, P. 2936-2942

115.  Sparsity constrained sinogram inpainting for metal artifact reduction in x-ray computed tomography

Mehranian A, M.R. Ay , Rahmim A, and Zaidi H
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Valencia, Spain, 23-29 October 2011, p. 3694–3699

116.  B-spline based free form deformation thoracic non-rigid registration of CT and PET images

Khodadad D, Ahmadian A, M.R. Ay, Esfahani AF, Banaem HY and Zaidi H
Proceeding and Conference Record
International Conference on Graphic and Image Processing (ICGIP 2011), 1-3 October 2011, Cairo, Egypt, Proc. SPIE, Vol. 8285, pp 82851K

117.  A Novel Phantom for Accurate Performance Assessment of Bone Mineral Measurement Techniques: DEXA and QCT

A. Emami, H. Ghadiri, M.R. Ay, S. Akhlagpour, A. Eslami, P. Ghafarian and S. Taghizadeh
Proceeding and Conference Record
5th Kuala Lumpur International Conference on Biomedical Engineering, 20-23 June 2011, Kuala Lumpur, Malaysia, IFMBE Proceedings 35, p. 47-50

118.  Monte Carlo Characterization of Scattered radiation profile in Volumetric 64 slice CT using GATE

A. Najafi Darmian, M.R. Ay, M. Pouladian, A. Shirazi, H.Ghadiri and A. Akbarzadeh
Proceeding and Conference Record
5th Kuala Lumpur International Conference on Biomedical Engineering, 20-23 June 2011, Kuala Lumpur, Malaysia, IFMBE Proceedings 35, p. 694-697

119.  Quantification of Inter-crystal Scattering and Parallax Effect in Pixelated High Resolution Small Animal Gamma Camera: A Monte Carlo Study

F. Adibpour, M.R. Ay, S. Sarkar and G. Loudos
Proceeding and Conference Record
5th Kuala Lumpur International Conference on Biomedical Engineering, 20-23 June 2011, Kuala Lumpur, Malaysia, IFMBE Proceedings 35, p. 708-711

120.  Quantitative Assessment of the influence of crystal material and size on the Inter Crystal Scattering and Penetration effect in pixilated dual head small animal PET scanner

N. Ghazanfari, M.R. Ay, N. Zeraatkar, S. Sarkar and G. Loudos
Proceeding and Conference Record
5th Kuala Lumpur International Conference on Biomedical Engineering, 20-23 June 2011, Kuala Lumpur, Malaysia, IFMBE Proceedings 35, p. 712-715

121.  Accurate Monte Carlo modeling and performance assessment of the X-PET™ subsystem of the FLEX Triumph™ preclinical PET/CT scanner

N. Zeratkar, M.R. Ay, A Kamaliasl and H. Zaidi
Peer-reviewed Journal Publication
Medical Physics, 2011, Vol. 38, No 3, pp 1217-1225

122.  Assessment of the impact of applying attenuation correction on the accuracy of activity recovery in TC99m-ECD brain SPECT of healthy subject using statistical parameter mapping

F. Vedaei, M.R. Ay, A. Kamali asl, F. Kalantari
Published Abstract
3th International Congress of Nuclear Medicine, Tehran, Iran, 2011, pp 92

123.  Assessment of the impact of applying attenuation correction on the accuracy of activity recovery in Tc99m-ECD brain SPECT of healthy subject using Statistical Parametric Mapping (SPM)

F. Vedaei, A. Kamali asl, F. Kalantari, M. Ansari, M.R. Ay
Peer-reviewed Journal Publication
Iranian Journal of Nuclear Medicine, 2011, 19, pp. 52-59

124.  Assessment of the influence of crystal material and size on the performance of dual head small animal PET scanners

N. Ghazanfari, M.R. Ay, S. Sarkar and G. Lodous
Published Abstract
3th International Congress of Nuclear Medicine, Tehran, Iran, 2011, pp 108

125.  Bone material decomposition by energy resolved CT-based attenuation correction of PET

H. Ghadiri, M. Shiran, M.R. Ay, H. Zaidi, H. Soltanian Zadeh
Published Abstract
3th International Congress of Nuclear Medicine, Tehran, Iran, 2011, pp 98

126.  Comparative assessment of energy-mapping approaches in CT-based attenuation correction for PET

M. R. Ay, M. Shirmohammad, S. Sarkar, A. Rahmim, H. Zaidi
Peer-reviewed Journal Publication
Molecular Imaging & Biology, 2011, Vol. 13, pp. 187-198

127.  Correction of contrast agent induced srtifacts in CT-based attenuation correction of cardiac PET data using a semi-automated segmentation algorithm

P. Ghafarian, M.R. Ay and J. Hassani
Published Abstract
3th International Congress of Nuclear Medicine, Tehran, Iran, 2011, pp 110

128.  CT-based attenuation correction on the FLEX Triumph™ preclinical PET/CT scanner

R. Prasad, M.R. Ay, O. Ratib and H. Zaidi
Peer-reviewed Journal Publication
IEEE Trans Nuclear Sciences, 2011, Vol. 58 pp 66-75

129.  Investigation of Time-of-Flight Benefits on the LYSO-Based PET/CT Scanner: A Monte Carlo Study Using GATE

P. Geramifar, M.R. Ay, M. Shamsaie Zafarghandi, S. Sarkar, G. Loudos, A. Rahmim
Peer-reviewed Journal Publication
Nuclear. Instrumentation Methods in Physics Research A , 2011 Vol. 641, pp. 121-127

130.  Is Metal Artifact Reduction Mandatory in Cardiac PET/CT Imaging in the Presence of Pacemaker and Implantable Cardioverter Defibrillator leads?

P. Ghafarian, S.M.R. Aghamiri, M.R. Ay, A. Rahmim, T. Schindler, O. Ratib and H. Zaidi
Peer-reviewed Journal Publication
European Journal of Nuclear Medicine and Molecular Imaging, 2011, Vol. 38, No. 2, pp 252-262

131.  Is percentage error of bone density determined by DEXA technique influenced by density?

A. Emami, H. Ghadiri, M.R. Ay, S. Akhlagpour, P. Ghafarian and S. Taghizadeh
Published Abstract
3th International Congress of Nuclear Medicine, Tehran, Iran, 2011, pp 88

132.  Monte Carlo estimation of electron contamination in a 18MV clinical photon beam

M. Allahverdi, M. Zabih Zadeh, M.R. Ay, S.R. Mahdavi, M. Shahriari ,A. Mesbahi and H. Alijanzadeh
Peer-reviewed Journal Publication
Iranian Journal of Radiation Research, 2011, Vol. 9 pp 15-28

133.  Monte Carlo-based evaluation of inter-crystal scatter and penetration in the PET subsystem of three GE Discovery PET/CT scanners

N. Zeraatkar, M. R. Ay, P. Ghafarian, S. Sarkar, P. Geramifar, and A. Rahmim
Peer-reviewed Journal Publication
Nuclear. Instrumentation Methods in Physics Research A, 2011, Vol. 659, pp. 508-514

134.  Novel detector design for reducing inter-cell x-ray cross-talk in the variable resolution x-ray CT scanner: A Monte Carlo study

H. Arabi, A Kamaliasl, M.R. Ay and H. Zaidi
Peer-reviewed Journal Publication
Medical Physics, 2011, Vol. 30 pp. 1389-1396

135.  Photon scatter and penetration in parallel hole collimator in preclinical Gamma Camera: A Monte Carlo study

F. Adibpour, M.R. Ay, S. Sarkar and G. Lodous
Published Abstract
3th International Congress of Nuclear Medicine, Tehran, Iran, 2011, pp 147

136.  Qualitative and quantitative assessment of metal artefacts arising from implantable cardiac pacing devices in oncological PET/CT studies: A phantom study

M.R. Ay, A. Mehranian, M. Abdoli, P. Ghafarian and H. Zaidi
Peer-reviewed Journal Publication
Molecular Imaging & Biology, 2011, Vol. 13, pp. 1077-1088

137.  Quantification of bremsstrahlung images with respect to post radioemoblization liver dosimetry

M.R. Teimoori, Sh. Akhlagpour, M.R. Ay, F. Kalantari and M. Amoui
Published Abstract
3th International Congress of Nuclear Medicine, Tehran, Iran, 2011, pp 103

138.  The influence of misalignment between PET and CT images on the accuracy of CT-based attenuation correction in thorax imaging: a simuation study

A. Anvari, M.R. Ay and B. Fallahi
Published Abstract
3th International Congress of Nuclear Medicine, Tehran, Iran, 2011, pp 190

139.  Use of optimization transfer for enhanced direct 4D parametric imaging in myocardial perfusion PET

A. Rahmim, J. Tang, H. Muhy-ud-Din, M.R. Ay, and M. A. Lodge
Published Abstract
Society of Nuclear Medicine (SNM) Annual Meeting, 2011, San Antonio, Texas, USA, J. Nucl. Med., vol. 52 (Supplement 1): 265, 2011

140.  4D Respiratory motion-corrected Rb-82 myocardial perfusion PET imaging

A. Rahmim, J. Tang, M.R. Ay and F. M. Bengel
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Knoxville, Tennessee, 2010, pp. 3312-3316

141.  A new method for experimental characterization of scattered radiation in 64-slice CT scanner

A. Akbarzadeh, M.R. Ay ,H. Ghadiri, S.Sarkar
Peer-reviewed Journal Publication
Biomedical Imaging and Intervention Journal, 2010, 6(1):e3

142.  A Novel Approach for Implementation of Dual Energy Mapping Technique in CT-Based Attenuation Correction Using Single kVP Imaging: A Feasibility Study

B. Teimourian, M.R. Ay, H. Ghadiri, M. Shamsaei Zafarghandi and H. Zaidi
Proceeding and Conference Record
12th Mediterranean Conference on Medical and Biological Engineering and Computing (MEDICON 2010), Chalkidiki, Greece, MEDICON 2010, IFMBE Proceedings 29, pp. 220–223, 2010

143.  A Novel Model for Monte Carlo Simulation of Performance Parameters of the Rodent Research PET (RRPET) Camera Based on NEMA NU-4 Standards

N. Zeraatkar, M.R. Ay, A. Kamali-Asl and H. Zaidi
Proceeding and Conference Record
12th Mediterranean Conference on Medical and Biological Engineering and Computing (MEDICON 2010), Chalkidiki, Greece, MEDICON 2010, IFMBE Proceedings 29, pp. 311–314, 2010

144.  A Virtual Sinogram Method to Reduce Dental Metallic Implant Artefacts in CT-based Attenuation Correction for PET

M. Abdoli, M.R. Ay, A. Ahmadian and H. Zaidi
Peer-reviewed Journal Publication
Nuclear Medicine Communication, 2010, 31, 22-31

145.  Accurate 3D Dosimetry for Internal Radiotherapy by Considering the Effect of Nonuniform Activity Distribution

E. Saeedzadeh, A. Abbaspour, S. Sarkar, M.R. Ay, H.R. Khosravi
Published Abstract
The International Congress of Nuclear Medicine, Mashhad, Iran, Iranian Journal of Nuclear Medicine, Vol. 18, Supp. 1, 2010, pp. 112

146.  Accurate 3D-Dosimetry for Internal Radiotherapy with 131I Using GATE Monte Carlo Code

E. Saeed Zadeh, S. Sarkar, A. Abbaspour, M.R. Ay, H. Khosravi, G. Lodus
Published Abstract
9th Iranian Congress of Medical Physics, Tehran, Iran, 2010, pp 116

147.  Accurate Modeling for Monte Carlo Based Performance Evaluation of The PET Subsystem of the FLEX Triumph Priclinical PET/CT Scanner Using NEMA NU-4 Standard

N. Zeraatkar, M.R. Ay, A.R. Kamali-Asl, H. Zaidi
Published Abstract
10th Congress of the World Federation of Nuclear Medicine and Biology (WFNMB 2010), Cape Town, South Africa, South Africa, World Journal of Nuclear Medicine, Vol. 9, Supp. 1, 2010, pp. S-163
Nominated as one of the best submitted abstracts

148.  Advances in Multimodality Molecular Imaging Instrumentation

M.R. Ay
Published Abstract
The International Congress of Nuclear Medicine, Mashhad, Iran, Iranian Journal of Nuclear Medicine, Vol. 18, Supp. 1, 2010, pp. 77

149.  Assessment of the Influence of Crystal Material and Size on the Sensitivity of Dual Head Small Animal PET Scanner

N. Ghazanfari, M.R. Ay, S. Sarkar and G. Loudos
Published Abstract
The International Congress of Nuclear Medicine, Mashhad, Iran, Iranian Journal of Nuclear Medicine, Vol. 18, Supp. 1, 2010, pp. 120

150.  Assessment of the Influence of PET and CT Data Misalignment Errors in Cardiac PET/CT Examination: Patient and Phantom Studies

P. Ghafarian, S.M.R. Aghamiri, M.R. Ay, A. Fard Esfahani and H. Zaidi
Published Abstract
The International Congress of Nuclear Medicine, Mashhad, Iran, Iranian Journal of Nuclear Medicine, Vol. 18, Supp. 1, 2010, pp. 81

151.  Calculation Of Scattered Radiation Profile In 64 Slice CT Scanners Using Experimental Measurement

A. Akbarzadeh, M.R.Ay ,H.Ghadiri, S.Sarkar
Peer-reviewed Journal Publication
Iran J. Medical Physics , 2010, 6, 1-10

152.  Coronary calcium score scan-based attenuation correction in cardiovascular PET imaging

P. Ghafarian, S.M.R. Aghamiri, M.R. Ay, B. Fallahi, A. Rahmim, T. Schindler, O. Ratib and H. Zaidi
Peer-reviewed Journal Publication
Nuclear Medicine Communication, 2010, Vol. 31, No 9, pp 780-787

153.  Coronary Calcium Score Scan-Based Attenuation Correction in Viability PET Examination: A Feasibility Study

P. Ghafarian, S.M.R. Aghamiri, M.R. Ay, B. Fallahi, A. Rahmim, T. Schindler, O. Ratib and H. Zaidi
Published Abstract
10th Congress of the World Federation of Nuclear Medicine and Biology (WFNMB 2010), Cape Town, South Africa, World Journal of Nuclear Medicine, Vol. 9, Supp. 1, 2010, pp. S-16

154.  CT2MCNP: An Integrated Package for Constructing Patient-Specific Voxel-Based Phantoms Dedicated for MCNP(X) Monte Carlo Code

A. Mehranian, M.R. Ay and H. Zaidi
Proceeding and Conference Record
12th Mediterranean Conference on Medical and Biological Engineering and Computing (MEDICON 2010), Chalkidiki, Greece, MEDICON 2010, IFMBE Proceedings 29, pp. 319–322, 2010

155.  Effects of Crystal Pixel Size and Collimator Geometry on the Performance of a Pixelated Crystal Gamma Camera Using Monte Carlo Simulation

M. Rasouli, A. Takavar, M.R. Ay, S. Saber, and G. Loudos
Peer-reviewed Journal Publication
Journal of Nuclear Medicine Technology, 2010, Vol. 38, No 4, pp 199-204

156.  Evaluation of Dose Distribution in Co-60 Machine Using Radicromic Film and Monte Carlo

M. Mollazadeh, , M. Allahverdi, T. Pourfallah, N. Riahi Alam, M.R. Ay
Published Abstract
16th Conference of Biomedical Engineering, Tehran, Iran, 2010, PP. 157

157.  Evaluation of MRI-based Polymer Gel Dosimetry for Measurement of CT Dose Index (CTDI) on 64 slices CT Scanners

L. Karimi-Afshar, N. Riahi Alam, M.R.Ay, M. Allahverdi, T. Purfallah, H. Hashemi, A. Farahani, B. Efie, M. Bakhteiari
Peer-reviewed Journal Publication
Iran J. Medical Physics , 2010, 6, 59-70

158.  Experimental Measurement of Modulation Transfer Function (MTF) in Five Commercial CT Scanners

S.M. Akbari, M.R. Ay, A. Kamali Asl, H. Ghadiri and H. Zaidi
Proceeding and Conference Record
12th Mediterranean Conference on Medical and Biological Engineering and Computing (MEDICON 2010), Chalkidiki, Greece, MEDICON 2010, IFMBE Proceedings 29, pp. 351–354, 2010

159.  Impact of Metal Artifact Reduction on Cardiac FDG-PET/CT Studies in the Presence pf pacemaker and Implantable Cardio Verter Defibrator Leads

P. Ghafarian, S.M.R. Aghamiri, M.R. Ay, A. Fard Esfahani, A. Rahmim, T.H. Schindler, O. Ratib and H. Zaidi
Published Abstract
The International Congress of Nuclear Medicine, Mashhad, Iran, Iranian Journal of Nuclear Medicine, Vol. 18, Supp. 1, 2010, pp. 104

160.  Implementation and Comparison of to Empirical Methods for Calculation of MTF in CT

M. Akbari, M.R. Ay, A. Kamali Asl, H. Ghadiri
Published Abstract
16th Conference of Biomedical Engineering, Tehran, Iran, 2010, PP. 155

161.  Measurement of scattered radiation in a volumetric 64-slice CT scanner using three experimental techniques

A. Akbarzadeh, M. R. Ay, H. Ghadiri, S. Sarkar and H. Zaidi
Peer-reviewed Journal Publication
Physics Medicine and Biology, 2010, 55, 2269-2280

162.  Optimization of weighted virtual sinogram-based metal artifact reduction in CT-based attenuation correction of PET data using a genetic algorithm

M. Abdoli, M.R. Ay, A. Ahmadian, R.A. Dierckx and H. Zaidi
Published Abstract
European Association of Nuclear Medicine Annual Congress, 9-13 October 2010, Vienna, Austria. Eur J Nucl Med Mol Imaging, Vol 37, Suppl. 1, (2010)

163.  Performance Assessment and Optimization of Pixelated Gamma Camera with Small Field of View: A Monte Carlo Study

F. Adibpour, M.R. Ay, S. Sarkar and G. Loudos
Published Abstract
The International Congress of Nuclear Medicine, Mashhad, Iran, Iranian Journal of Nuclear Medicine, Vol. 18, Supp. 1, 2010, pp. 116

164.  Quantification and Correction of Metallic Artifact Arising from Implantable cardiac Pacing Devices in PET/CT Studies: A Phantom Study

M.R. Ay, A. Mehranian, P. Ghafarian, M. Abdoli and H. Zaidi
Published Abstract
10th Congress of the World Federation of Nuclear Medicine and Biology (WFNMB 2010), Cape Town, South Africa, South Africa, World Journal of Nuclear Medicine, Vol. 9, Supp. 1, 2010, pp. S-20
Nominated as one of the best submitted abstracts

165.  Quantification of Inter Crystal Scatter and Parallax Events in LYSO-Based Discovery RX PET/CT Scanner: A Monte Carlo Study

N. Zeraatkar, M.R. Ay, S. Sarkar, A. Rahmim, P. Geramifar
Published Abstract
10th Congress of the World Federation of Nuclear Medicine and Biology (WFNMB 2010), Cape Town, South Africa, South Africa, World Journal of Nuclear Medicine, Vol. 9, Supp. 1, 2010, pp. S-158
Nominated as one of the best submitted abstracts

166.  Quantification of Inter-Crystal Scatter and Penetration Events in GE Discovery RX PET/CT Scanner: a Monte Carlo Simulation

N. Zeraatkar, M.R. Ay, S. Sarkar, P. Geramifar and A. Rahmim
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Knoxville, Tennessee, 2010, pp. 2403-2408

167.  Quantification of Respiratory Induced Artifact in CT-Based Attenuation Correction of PET Data: A Simulation Study

Z. Anvari, M.R. Ay, B. Fallahi, F. Buther
Published Abstract
The International Congress of Nuclear Medicine, Mashhad, Iran, Iranian Journal of Nuclear Medicine, Vol. 18, Supp. 1, 2010, pp. 79

168.  Quantifying the effect of anode surface roughness on diagnostic x-ray spectra using Monte Carlo simulation

A. Mehranian, M.R. Ay, N. Riahi and H. Zaidi
Peer-reviewed Journal Publication
Medical Physics, 2010, 37, 742-752

169.  Quantitative Assessment if Inter-Crystal Scatter and Penetration in the PET Subsystem of the FLEX Triumph Preclinical Multi-Modality Scanner

H. Arabi, N. Zeratkar, M.R. Ay, H. Zaidi
Published Abstract
The International Congress of Nuclear Medicine, Mashhad, Iran, Iranian Journal of Nuclear Medicine, Vol. 18, Supp. 1, 2010, pp. 40

170.  Reduction of dental filling metallic artefacts in CT-based attenuation correction of PET data using weighted virtual sinograms optimized by a genetic algorithm

M. Abdoli, M.R. Ay, A. Ahmadian, A. J. O. Dierckx and H. Zaidi
Peer-reviewed Journal Publication
Medical Physics, 2010, Vol. 37, No 12, pp 6166-6177

171.  The Effect of Nonuniform Activity Distribution in Three-Dimensional Dosimetry for Internal Radiotherapy with 131I

E. Saeed Zadeh, S. Sarkar, A. Abbaspour, M.R. Ay, H. Khosravi, G. Lodus
Published Abstract
10th Congress of the World Federation of Nuclear Medicine and Biology (WFNMB 2010), Cape Town, South Africa, South Africa, World Journal of Nuclear Medicine, Vol. 9, Supp. 1, 2010, pp. S-30

172.  The Influence of Patient Miscentering of Patient Dose and Image Noise in Two Commercial CT Scanners

M. Habibzadeh, M.R. Ay, A. Kamali Asl, H. Ghadiri
Published Abstract
16th Conference of Biomedical Engineering, Tehran, Iran, 2010, PP. 158

173.  The Influence of Patient Miscentering on Patient Dose and Image Noise in Two Commercial CT Scanners

M.A. Habibzadeh, M.R. Ay, A. Kamali Asl, H. Ghadiri and H. Zaidi
Proceeding and Conference Record
12th Mediterranean Conference on Medical and Biological Engineering and Computing (MEDICON 2010), Chalkidiki, Greece, MEDICON 2010, IFMBE Proceedings 29, pp. 327–330, 2010

174.  Virtual Dual Energy CT (VDECT): A Novel Approach for Improved Energy Mapping in CT-Based Attenuation Correction of PET Data

B. Teimourian, M.R. Ay, M. Shamsaei Zafarghandi, H. Ghadiri and H. Zaidi
Published Abstract
10th Congress of the World Federation of Nuclear Medicine and Biology (WFNMB 2010), Cape Town, South Africa, South Africa, World Journal of Nuclear Medicine, Vol. 9, Supp. 1, 2010, pp. S-33

175.  A Novel Application of MRI-Polymer Gel Dosimeter for Measurement of CTDI on X-Ray 64 Slices CT Scanner

L. Karimiafshar, N. Riyahi Alam, M.R. Ay, M. Alahverdi, T. Alahvirdi Pourfallah , H. Hashemi, A. Farahani,B. Rafiei and M. Bakhtiar
Proceeding and Conference Record
The World Congress on Medical Physics and Biomedical Engineering, Germany, Munich, 7-12 September 2009, IFMBE Proceedings 25, pp. 541-544

176.  CT-based attenuation correction on the FLEX Triumph™ preclinical PET/CT scanner

R. Prasad, M.R Ay, O. Ratib and H. Zaidi
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Orlando (FL) USA, 25-31 October 2009, 3357-3362

177.  Quantitative assessment of the effect of anode surface roughness on diagnostic x-ray spectra using Monte Carlo simulation

A. Mehranian , M.R. Ay, N. Riahi Alam and H. Zaidi
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Orlando (FL) USA, 25-31 October 2009, 2902-2907

178.  Reduction of dental filling metallic artifacts in CT-based attenuation correction of PET data using weighted virtual sinograms

M. Abdoli , M.R. Ay, A. Ahmadian and H. Zaidi
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Orlando (FL) USA, 25-31 October 2009, 2752-2755

179.  Comparative assessment of image- and virtual sinogram-based metal artefact reduction techniques for CT-based attenuation correction in PET

M. Abdoli, M.R. Ay, A. Ahmadian and H. Zaidi
Published Abstract
European Association of Nuclear Medicine Annual Congress, 10-14 October 2009, Barcelona, Spain. Eur J Nucl Med Mol Imaging, Vol 36, Suppl. 1, pp S226

180.  The Effect of Crystal Size on Position Detection Accuracy in PET Block Detectors: A Monte Carlo Study

S. Lashkari, S. Sarkar, M.R. Ay and A. Rahmim
Published Abstract
European Association of Nuclear Medicine Annual Congress, 10-14 October 2009, Barcelona, Spain. Eur J Nucl Med Mol Imaging, Vol 36, Suppl. 1, pp S409

181.  Challenges for Planning and Running a PET/CT and Cyclotron Facility

M.R. Ay
Published Abstract
International Congress of Nuclear Medicine and Molecular Imaging, Tabriz, Iran, 23-25 September, 2009, pp. 10

182.  CT Based Attenuation Correction in Cardiac PET/CT Using Calcium Score CT Image: A Feasibility Study

P. Ghafarian, S.M.R. Aghamiri, M.R. Ay, A. Rahmim and H. Zaidi
Published Abstract
International Congress of Nuclear Medicine and Molecular Imaging, Tabriz, Iran, 23-25 September, 2009, pp. 9

183.  Implementation and comparison of different energy mapping approaches in CT-based attenuation correction of PET

M.R.Ay, M. Shirmohammad, S. Sarkar, A. Rahmim, H. Zaidi
Published Abstract
International Congress of Nuclear Medicine and Molecular Imaging, Tabriz, Iran, 23-25 September, 2009, pp. 51

184.  Implementation of Dual Energy Mapping Techniques in CT-Based Attenuation Correction Method Using Single Energy Imaging: A Novel Approach for Reducing Patient Dose

B. Teimourian, M.R. Ay, M. Shamsaei Zafarghandi
Published Abstract
International Congress of Nuclear Medicine and Molecular Imaging, Tabriz, Iran, 23-25 September, 2009, pp. 52

185.  Strategies for Attenuation Correction in PET/CT and PET/MRI

M.R. Ay
Published Abstract
International Congress of Nuclear Medicine and Molecular Imaging, Tabriz, Iran, 23-25 September, 2009, pp. 8

186.  Validation of the GATE Monte Carlo Code in Evaluation of Organ Doses Calculation in Zubal Voxelized Phantom

E. Saeedzadeh, S. Sarkar, A. Abbaspour Tehrani-Fard, M.R. Ay, H.R. Khosravi
Published Abstract
International Congress of Nuclear Medicine and Molecular Imaging, Tabriz, Iran, 23-25 September, 2009, pp. 50

187.  Monte Carlo Estimation of Photoneotrons Contamination from High Energy Medical Accelerator in Treatment Room and Maze

M. Zabih Zadeh, M.R. Ay, M. Allahverdi, A. Mesbahi, S.R. Mahdavi and M. Shahriari
Published Abstract
10th Biennial ESTRO Conference on Physics and Radiation Technology for Clinical Radiotherapy, Maastricht, August 30 – September 3, 2009

188.  Metal Artifact Reduction in CT-Based Attenuation Correction of PET Data Using the Virtual Sinogram Concept

M. Abdoli, M.R. Ay, A. Ahmadian and H. Zaidi
Proceeding and Conference Record
3rd International Conference on Bioinformatics and Biomedical Engineering (IEEE iCBBE 2009), June 11th to 13th, 2009, 1-4, Beijing, China

189.  Quantification of PET and CT Data Misalignment Errors in Cardiac PET/CT: Clinical and Phantom Studies

P. Ghafarian and S.M.R. Aghamiri, M.R. Ay, A. Rahmim and H. Zaidi
Proceeding and Conference Record
3rd International Conference on Bioinformatics and Biomedical Engineering (IEEE iCBBE 2009), June 11th to 13th, 2009, 1-4, Beijing, China

190.  The Influence of X-ray Spectra Filtration on Image Quality and Patient Dose in the GE VCT 64-Slice Cardiac CT Scanner

M.R. Ay, A. Maleki, H. Ghadiri, P. Ghafarian, A. Ahmadian and H. Zaidi
Proceeding and Conference Record
The 3rd International Conference on Bioinformatics and Biomedical Engineering (IEEE iCBBE 2009), June 11th to 13th, 2009, 1-4, Beijing, China

191.  Evaluation of polymer gel dosimetry based on MRI imaging for measurement of CTDI in 64 slice CT scanner

L. Karimiafshar, N. Riahi Alanm and M.R. Ay
Published Abstract
1st Congress of Radiation Protection in Radiotherapy, Diagnostic and Interventional Radiology, 19-20 February 2009, Tehran, Iran

192.  PET/CT: Site Planning and Shielding Calculation

M.R. Ay
Published Abstract
1st Congress of Radiation Protection in Radiotherapy, Diagnostic and Interventional Radiology, 19-20 February 2009, Tehran, Iran, 43-44

193.  A Novel Dual Energy CT-Based Attenuation Correction Method in PET/CT Systems: A Phantom Study

B. Teymoorian, M.R. Ay, M. Shamsaei Zafarghandi and H. Ghadiri
Peer-reviewed Journal Publication
" Iranian Journal of Nuclear Medicine, 2009, 17, 42-49

194.  Differential Dose Volume Histograms of Gamma Knife in Presence of Inhomogeneities Using MRI- polymer Gel Dosimetry and MC Simulation

T. Allahverdi, M. Allahverdi, N. Riahi Alam, M.R. Ay, M. Zahmatkesh
Peer-reviewed Journal Publication
Medical Physics, 2009, 36,3002-3012

195.  Evaluation of Dose Delivery Accuracy of Gamma Knife Using MRI Polymer Gel Dosimeter in an Inhomogeneous Phantom

T. Allahverdi, M. Allahverdi, N. Riahi Alam, M.R. Ay, M. Zahmatkesh
Peer-reviewed Journal Publication
Journal of Physics: Conference Series 164, 2009, doi:10.1088/1742-6596/164/1/012066

196.  Monte Carlo Estimation of Photoneotrons Contamination from High Energy Medical Accelerator in Threatment Room and Maze: A Simplified Model

M. Zabih Zadeh, M.R. Ay, M. Allahverdi, A. Mesbahi, S.R. Mahdavi and M. Shahriari
Peer-reviewed Journal Publication
Radiation Detection Dosimetry, 2009, 135, 21-32

197.  Performance Comparison of Four Commercial GE Discovery PET/CT Scanners: A Monte Carlo Study Using GATE

P. Geramifar, M.R. Ay, M. Shamsaie Zafarghandi,G. Loudos, A. Rahmim
Peer-reviewed Journal Publication
Iranian Journal of Nuclear Medicine, 2009, 17, 26-33

198.  Performance evaluation of MRI-based PAGAT polymer gel dosimeter in an inhomogeneous phantom using EGSnrc code on a co-60 machine

T. Allahverdi, M. Allahverdi, N. Riahi Alam, M.R. Ay, M. Zahmatkesh and J.S. Ibbott
Peer-reviewed Journal Publication
Applied Radiation and Isotopes, 2009, 67, 186-191

199.  Verifying the accuracy of dose distribution in Gamma Knife unit in presence of inhomogeneities using PAGAT polymer gel dosimeter and MC simulation

T. Allahverdi, M. Allahverdi, N. Riahi Alam, M.R. Ay, M. Zahmatkesh
Peer-reviewed Journal Publication
Iranian J. of Radiation Research, 2009, 7, 49-56

200.  A novel approach for reducing dental filling artefacts in CT-based attenuation correction of head and neck oncologic PET/CT data

M. Abdoli, M.R Ay, A. Ahmadian, N. Sahba and H. Zaidi
Proceeding and Conference Record
4th European Congress of the International Federation of Medical and Biological Engineering, Antwerp, Belgium, 23-27 November 2008 ECIFMBE 2008, IFMBE Proceedings 22, pp. 492–495

201.  Comparative assessment of different energy mapping approaches in CT based attenuation correction: a patient study

M. Shirmohammad, M.R. Ay, A. Rahmim, S. Sarkar and H. Zaidi
Proceeding and Conference Record
4th European Congress of the International Federation of Medical and Biological Engineering, Antwerp, Belgium, 23-27 November 2008 ECIFMBE 2008, IFMBE Proceedings 22, pp. 496–499

202.  Comparative Assessment of Rotating Slat and Parallel Hole Collimator Performance in GE DST-Xli Gamma Camera: A Monte Carlo Study

N. Dehestani, S. Sarkar, M.R. Ay, M. Sadeghi and M. Shafaei
Proceeding and Conference Record
4th European Congress of the International Federation of Medical and Biological Engineering, Antwerp, Belgium, 23-27 November 2008 ECIFMBE 2008, IFMBE Proceedings 22, pp. 1062–1065

203.  Monte Carlo assessment of geometric, scatter and septal penetration components in high energy collimators

M. Shafaei, M.R. Ay, S. Sardari and H. Zaidi
Proceeding and Conference Record
4th European Congress of the International Federation of Medical and Biological Engineering, Antwerp, Belgium, 23-27 November 2008 ECIFMBE 2008, IFMBE Proceedings 22, pp. 2479–2482

204.  Reduction of Intravenous Contrast Related Artifacts in CT-based Attenuation Corrected PET Images

M.R. Ay, J.H. Bidgoli, P. Ghafarian and H. Zaidi
Proceeding and Conference Record
4th European Congress of the International Federation of Medical and Biological Engineering, Antwerp, Belgium, 23-27 November 2008 ECIFMBE 2008, IFMBE Proceedings 22, pp. 513–516

205.  The Influence of InterCrystal Scattering on Detection Efficiency of Dedicated Breast Gamma Camera: A Monte Carlo Study

M. Rasouli, M.R. Ay, A. Takavar, S. Lashkari and G. Loudos
Proceeding and Conference Record
4th European Congress of the International Federation of Medical and Biological Engineering, Antwerp, Belgium, 23-27 November 2008 ECIFMBE 2008, IFMBE Proceedings 22, pp. 2451–2454

206.  Characterization of Scatter and Penetration Using Monte Carlo Simulation in Ga-67 Imaging

M. Shafaee, M.R. Ay and D. Sardari
Published Abstract
9th ASIA Oceania Congress of Nuclear Medicine and Biology, Oct 31st - Nov 4th, 2008, New Delhi, India, Indian Journal of Nuclear Medicine, Vol 23, p.171

207.  A hybrid approach for accurate estimation of the scatter component in x-ray CT combining experimental measurements and Monte Carlo simulations

A. Akbarzadeh, M.R. Ay, H. Ghadiri, S. Sarkar and H. Zaidi
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Dresden, Germany, 19-25 October 2008, 3864-3867

208.  Monte Carlo Based Performance Assessment of Four Commercial GE Discovery PET/CT Scanners Using GATE

P. Geramifar, M.R. Ay, M. Shamsai Zafarghandi, G. Loudos, A. Rahmim
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Dresden, Germany, 19-25 October 2008, 3995-3999

209.  Rb-82 Cardiac PET Imaging with Resolution Modeling

A. Rahmim, J. Tang, M. A. Lodge, S. Lashkari, M.R. Ay, R. Lautamaki, B. M. W. Tsui, and F. Bengel
Proceeding and Conference Record
IEEE Nuclear Science Symposium & Medical Imaging Conference, Dresden, Germany, 19-25 October 2008, 3643-3650

210.  A novel energy mapping method for attenuation map generation at 511 keV in computed tomography based attenuation correction

M. Shirmohammad, M.R. Ay, A. Rahmim A, S. Sarkar and H. Zaidi
Published Abstract
European Association of Nuclear Medicine Annual Congress, 11-15 October 2008, Munich, Germany. Eur J Nucl Med Mol Imaging, Vol 35, Suppl. 2, S146
Nominated as one of the best submitted abstracts