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Title: SU-E-T-655: Quantifying the Dosimetric Characteristics of a Calypso Compatible Radiotherapy Treatment Couch with Angular Transmission Functions

Abstract

Purpose: To quantified the dosimetric characteristics of a Calypso compatible radiotherapy couch using continuously scanned transmission factor as a function of gantry angle. Methods: Radiation dose as a function of gantry angle was measured with an ionization chamber at the center of a 30 cm diameter cylindrical phantom placed on Qfix kVue Calypso compatible couch. A 3-D scanner was employed to continuously scan the dose during an arc rotation delivery. Nearly continuous transmission curves of 0.03° step size were obtained from IEC gantry angle 90° to180° for 6 MV and 15 MV photon beams at three couch longitudinal positions (due to longitudinally non-uniform shape of the couch rails) with rails both at the center and on sides. The transmission curves were evaluated to assess the attenuation by the couch. They were also compared to those of a carbon fiber couch top. Results: The scanned transmission curves of the Calypso comptible couch showed fine details of the couch transmission as a function of gantry angle. The attenuation by the couch varied from 2.4% to 12.9% for the 6 MV photo beam and from 1.8% to 8.9% for the 15 MV photon beam depending on the gantry angle. The attenuation by themore » flat couch top is only approximately 2 to 3%, but by the rail is much more significant. Because the rails are not uniformly shaped in the longitudinal direction, attenuation by the rail for the same gantry angle varied with the rail longitudinal position. The transmission curves of the carbon fiber couch top are nearly identical to those of the Calypso compatible couch top. Conclusion: The Calypso compatible couch attenuates radiation by 2.4%–12.9% and 1.8%–8.9% for 6 MV and 15 MV photon beams, respectively. The attenuation by the rails is much more significant than the flat couch top.« less

Authors:
; ; ; ; ; ; ;  [1]
  1. Univ Alabama Birmingham, Birmingham, AL (United States)
Publication Date:
OSTI Identifier:
22538164
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 42; Journal Issue: 6; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 61 RADIATION PROTECTION AND DOSIMETRY; ATTENUATION; CARBON FIBERS; DOSIMETRY; IONIZATION CHAMBERS; PHOTON BEAMS; RADIATION DOSES; RADIOTHERAPY; TRANSMISSION

Citation Formats

Duan, J, Shen, S, Wu, X, Popple, R, Cardan, R, Huang, M, Tannazi, F, and Brezovich, I. SU-E-T-655: Quantifying the Dosimetric Characteristics of a Calypso Compatible Radiotherapy Treatment Couch with Angular Transmission Functions. United States: N. p., 2015. Web. doi:10.1118/1.4925018.
Duan, J, Shen, S, Wu, X, Popple, R, Cardan, R, Huang, M, Tannazi, F, & Brezovich, I. SU-E-T-655: Quantifying the Dosimetric Characteristics of a Calypso Compatible Radiotherapy Treatment Couch with Angular Transmission Functions. United States. doi:10.1118/1.4925018.
Duan, J, Shen, S, Wu, X, Popple, R, Cardan, R, Huang, M, Tannazi, F, and Brezovich, I. Mon . "SU-E-T-655: Quantifying the Dosimetric Characteristics of a Calypso Compatible Radiotherapy Treatment Couch with Angular Transmission Functions". United States. doi:10.1118/1.4925018.
@article{osti_22538164,
title = {SU-E-T-655: Quantifying the Dosimetric Characteristics of a Calypso Compatible Radiotherapy Treatment Couch with Angular Transmission Functions},
author = {Duan, J and Shen, S and Wu, X and Popple, R and Cardan, R and Huang, M and Tannazi, F and Brezovich, I},
abstractNote = {Purpose: To quantified the dosimetric characteristics of a Calypso compatible radiotherapy couch using continuously scanned transmission factor as a function of gantry angle. Methods: Radiation dose as a function of gantry angle was measured with an ionization chamber at the center of a 30 cm diameter cylindrical phantom placed on Qfix kVue Calypso compatible couch. A 3-D scanner was employed to continuously scan the dose during an arc rotation delivery. Nearly continuous transmission curves of 0.03° step size were obtained from IEC gantry angle 90° to180° for 6 MV and 15 MV photon beams at three couch longitudinal positions (due to longitudinally non-uniform shape of the couch rails) with rails both at the center and on sides. The transmission curves were evaluated to assess the attenuation by the couch. They were also compared to those of a carbon fiber couch top. Results: The scanned transmission curves of the Calypso comptible couch showed fine details of the couch transmission as a function of gantry angle. The attenuation by the couch varied from 2.4% to 12.9% for the 6 MV photo beam and from 1.8% to 8.9% for the 15 MV photon beam depending on the gantry angle. The attenuation by the flat couch top is only approximately 2 to 3%, but by the rail is much more significant. Because the rails are not uniformly shaped in the longitudinal direction, attenuation by the rail for the same gantry angle varied with the rail longitudinal position. The transmission curves of the carbon fiber couch top are nearly identical to those of the Calypso compatible couch top. Conclusion: The Calypso compatible couch attenuates radiation by 2.4%–12.9% and 1.8%–8.9% for 6 MV and 15 MV photon beams, respectively. The attenuation by the rails is much more significant than the flat couch top.},
doi = {10.1118/1.4925018},
journal = {Medical Physics},
number = 6,
volume = 42,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}