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Ahmet Sedat Ayan

  • Most Common Publication Keywords # of Pubs
  • LARGE DETECTOR SYSTEMS FOR PARTICLE AND ASTROPARTICLE PHYSICS3
  • CALIBRATION2
  • CALORIMETERS2
  • DESIGN2
  • ATLAS DETECTOR1
  • BROKEN SYMMETRIES1
  • COLLIMATOR1
  • COMPUTED TOMOGRAPHY1
  • COMPUTED-TOMOGRAPHY1
  • FAN-BEAM1
  • Most Common Publication Subject Categories # of Pubs
  • RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING6
  • INSTRUMENTS & INSTRUMENTATION3
  • ONCOLOGY2
  • ENGINEERING, BIOMEDICAL1
  • ENGINEERING, ELECTRICAL & ELECTRONIC1
  • MULTIDISCIPLINARY SCIENCES1
  • NUCLEAR SCIENCE & TECHNOLOGY1

Most Recent Journal Articles

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  • Lu, L, Filippi, J, Patel, A, Gupta, N, Weldon, M, Woollard,J, Ayan,A, Rong, Y, Martin, D, Pelloski,C, Welliver, XU. "A Clinical Dosimetry Analysis of Total Body Irradiation for Leukemia Patients." International Journal of Medical Physics, Clinical Engineering and Radiation Oncology. Vol. 3, no. 1. (Dec 2013): 31-42. (Published). Lu, L, Filippi, J, Patel, A, Gupta, N, Weldon, M, Woollard,J, Ayan,A, Rong, Y, Martin, D, Pelloski,C, Welliver, XU A Clinical Dosimetry Analysis of Total Body Irradiation for Leukemia Patients International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Journal Article Peer-Review
  • Ayan,Ahmet,S; Lin,Haibo; Yeager,Caitlyn; et al. "Should image rotation be addressed during routine cone-beam CT quality assurance?." PHYSICS IN MEDICINE AND BIOLOGY. Vol. 58, no. 4. (Feb 2013): 1059-1073. (Published).Citation Count: 0. Ayan,Ahmet,S; Lin,Haibo; Yeager,Caitlyn; Deville,Curtiland; McDonough,James; Zhu,Timothy,C; Anderson,Nathan; Bar Ad,Voichita; Lu,Hsiao-Ming; Both,Stefan Should image rotation be addressed during routine cone-beam CT quality assurance? PHYSICS IN MEDICINE AND BIOLOGY Journal Article Peer-Review 23363650 10.1088/0031-9155/58/4/1059 0031-9155 The purpose of this study is to investigate whether quality assurance (QA) for cone-beam computed tomography (CBCT) image rotation is necessary in order to ensure the accuracy of CBCT based image-guided radiation therapy (IGRT) and adaptive radiotherapy (ART). Misregistration of angular coordinates during CBCT acquisition may lead to a rotated reconstructed image. If target localization is performed based on this image, an under-or over-dosage of the target volume (TV) and organs at risk (OARs) may occur. Therefore, patient CT image sets were rotated by 1 degrees up to 3 degrees and the treatment plans were recalculated to quantify changes in dose-volume histograms. A computer code in C++ was written to model the TV displacement and overlap area of an ellipse shape at the target and dose prescription levels corresponding to the image rotation. We investigated clinical scenarios in IGRT and ART in order to study the implications of image rotation on dose distributions for: (1) lateral TV and isocenter (SBRT), (2) central TV and isocenter (IMRT), (3) lateral TV and isocenter (IMRT). Mathematical analysis showed the dose coverage of TV depends on its shape, size, location, and orientation relative to the isocenter. Evaluation of three first scenario for theta = 1 degrees showed variations in TV D95 in the context of IGRT and ART when compared to the original plan were within 2.7 +/- 2.6% and 7.7 +/- 6.9% respectively while variations in the second and third scenarios were less significant (<0.5%) for the angular range evaluated. However a larger degree of variation was found in terms of minimum and maximum doses for target and OARs. The rotation of CBCT image data sets may have significant dosimetric consequences in IGRT and ART. The TV's location relative to isocenter and shape determine the extent of alterations in dose indicators. Our findings suggest that a CBCT QA criterion of 1 degrees would be a reasonable action level to ensure accurate dose delivery. COMPUTED-TOMOGRAPHY|RADIATION-THERAPY|SYSTEMS|GEOMETRIC CALIBRATION Engineering, Biomedical|Radiology, Nuclear Medicine & Medical Imaging Links
  • Chatrchyan,S; Khachatryan,V; Sirunyan,A,M; et al. "A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider." SCIENCE. Vol. 338, no. 6114. (Dec 2012): 1569-1575. (Published).Citation Count: 16. Chatrchyan,S; Khachatryan,V; Sirunyan,A,M;et al. A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider SCIENCE Journal Article Peer-Review 10.1126/science.1230816 0036-8075 The Higgs boson was postulated nearly five decades ago within the framework of the standard model of particle physics and has been the subject of numerous searches at accelerators around the world. Its discovery would verify the existence of a complex scalar field thought to give mass to three of the carriers of the electroweak force-the W+, W-, and Z(0) bosons-as well as to the fundamental quarks and leptons. The CMS Collaboration has observed, with a statistical significance of five standard deviations, a new particle produced in proton-proton collisions at the Large Hadron Collider at CERN. The evidence is strongest in the diphoton and four-lepton (electrons and/or muons) final states, which provide the best mass resolution in the CMS detector. The probability of the observed signal being due to a random fluctuation of the background is about 1 in 3 x 10(6). The new particle is a boson with spin not equal to 1 and has a mass of about 1.25 giga-electron volts. Although its measured properties are, within the uncertainties of the present data, consistent with those expected of the Higgs boson, more data are needed to elucidate the precise nature of the new particle. SEARCH|WEAK INTERACTIONS|BROKEN SYMMETRIES|PARTICLES|PP COLLISIONS|LHC|GAUGE-THEORIES|MODEL HIGGS-BOSON|ATLAS DETECTOR|ROOT-S=7 TEV Multidisciplinary Sciences Links
  • Chatrchyan,S et al (CMS Collaboration). "Performance of the CMS drift tube chambers with cosmic rays." JOURNAL OF INSTRUMENTATION. Vol. 5, (Mar 2010): T03015. (Published).Citation Count: 28. Chatrchyan,S et al (CMS Collaboration) Performance of the CMS drift tube chambers with cosmic rays JOURNAL OF INSTRUMENTATION Journal Article Peer-Review 10.1088/1748-0221/5/03/T03015 1748-0221 Studies of the performance of the CMS drift tube barrel muon system are described, with results based on data collected during the CMS Cosmic Run at Four Tesla. For most of these data, the solenoidal magnet was operated with a central field of 3.8 T. The analysis of data from 246 out of a total of 250 chambers indicates a very good muon reconstruction capability, with a coordinate resolution for a single hit of about 260 mu m, and a nearly 100% efficiency for the drift tube cells. The resolution of the track direction measured in the bending plane is about 1.8 mrad, and the efficiency to reconstruct a segment in a single chamber is higher than 99%. The CMS simulation of cosmic rays reproduces well the performance of the barrel muon detector. MUON CHAMBER|large detector systems for particle and astroparticle physics|Particle tracking detectors (Gaseous detectors) Instruments & Instrumentation Links
  • Chatrchyan,S; Khachatryan,V; Sirunyan,A,M; et al. "Performance of CMS hadron calorimeter timing and synchronization using test beam, cosmic ray, and LHC beam data." JOURNAL OF INSTRUMENTATION. Vol. 5, (Mar 2010): T03013. (Published).Citation Count: 28. Chatrchyan,S; Khachatryan,V; Sirunyan,A,M; et al. Performance of CMS hadron calorimeter timing and synchronization using test beam, cosmic ray, and LHC beam data JOURNAL OF INSTRUMENTATION Journal Article Peer-Review 10.1088/1748-0221/5/03/T03013 1748-0221 This paper discusses the design and performance of the time measurement technique and of the synchronization systems of the CMS hadron calorimeter. Time measurement performance results are presented from test beam data taken in the years 2004 and 2006. For hadronic showers of energy greater than 100 GeV, the timing resolution is measured to be about 1.2 ns. Time synchronization and out-of-time background rejection results are presented from the Cosmic Run At Four Tesla and LHC beam runs taken in the Autumn of 2008. The inter-channel synchronization is measured to be within +/- 2 ns. DESIGN|CALIBRATION|calorimeters|large detector systems for particle and astroparticle physics Instruments & Instrumentation Links

Most Recent Conference Papers & Proceedings

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  • Salamekh,S; Rong,Y; Diavolitsis,V; Williams,T; Mayr,N; Ayan,A,S; Welliver,M,X. "Interfraction Tumor Volume Changes During Lung Stereotactic Body Radiation Therapy." In: INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS. Vol. 87. S68-S68. Peer-Review] (Published). Salamekh,S; Rong,Y; Diavolitsis,V; Williams,T; Mayr,N; Ayan,A,S; Welliver,M,X Interfraction Tumor Volume Changes During Lung Stereotactic Body Radiation Therapy 55th Annual Meeting of the Society-for-Radiation-Oncology Peer-Review 1 INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 0360-3016 Oncology|Radiology, Nuclear Medicine & Medical Imaging Web of Science ®
  • Welliver,M,X; Ayan,A,S; Lu,L; Rong,Y; Weldon,M; Cunningham,M; Jeffery,W; Gupta,N. "A New Method for Total Body Irradiation (TBI) Treatment Planning Using an "Irregular Surface Compensator"." In: INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS. Vol. 84. S864-S864. Peer-Review] (Published). Welliver,M,X; Ayan,A,S; Lu,L; Rong,Y; Weldon,M; Cunningham,M; Jeffery,W; Gupta,N A New Method for Total Body Irradiation (TBI) Treatment Planning Using an "Irregular Surface Compensator" 54th Annual Scientific Meeting of the American-Society-for-Radiation-Oncology (ASTRO) Peer-Review 1 INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 0360-3016 Oncology|Radiology, Nuclear Medicine & Medical Imaging Web of Science ®
  • Ayan,A; Lu,L; Rong,Y; Cunningham,M; Weldon,M; Welliver,M; Woollard,J; Gupta,N. "Feasibility of Using the 'Irregular Surface Compensator' Planning Feature of the Eclipse TPS for Total Body Irradiation (TBI) Treatment Planning." In: MEDICAL PHYSICS. Vol. 39. 3805-3805. Peer-Review] (Published). Ayan,A; Lu,L; Rong,Y; Cunningham,M; Weldon,M; Welliver,M; Woollard,J; Gupta,N Feasibility of Using the 'Irregular Surface Compensator' Planning Feature of the Eclipse TPS for Total Body Irradiation (TBI) Treatment Planning 54th Annual Meeting and Exhibition of the American-Association-of-Physicists-in-Medicine (AAPM) Peer-Review 1 MEDICAL PHYSICS 0094-2405 Radiology, Nuclear Medicine & Medical Imaging Web of Science ®
  • Ayan,A; Woollard,J; Gupta,N. "A Computer Program for Second Physics Manual Calculations in HDR Brachytherapy." In: MEDICAL PHYSICS. Vol. 39. 3716-3716. Peer-Review] (Published). Ayan,A; Woollard,J; Gupta,N A Computer Program for Second Physics Manual Calculations in HDR Brachytherapy 54th Annual Meeting and Exhibition of the American-Association-of-Physicists-in-Medicine (AAPM) Peer-Review 1 MEDICAL PHYSICS 0094-2405 Radiology, Nuclear Medicine & Medical Imaging Web of Science ®
  • Yeager,C; Lin,H; Ayan,A; McDonough,J; Both,S. "A Study to Establish the Effect of CBCT Image Rotational Displacement On IGRT and ART Lung SBRT Treatments." In: MEDICAL PHYSICS. Vol. 39. 3655-3655. Peer-Review] (Published). Yeager,C; Lin,H; Ayan,A; McDonough,J; Both,S A Study to Establish the Effect of CBCT Image Rotational Displacement On IGRT and ART Lung SBRT Treatments 54th Annual Meeting and Exhibition of the American-Association-of-Physicists-in-Medicine (AAPM) Peer-Review 1 MEDICAL PHYSICS 0094-2405 Radiology, Nuclear Medicine & Medical Imaging Web of Science ®