Evaluation of Radiation Dose and Image Quality for the Varian Cone Beam Computed Tomography System

Journal Article · Sun May 01 00:00:00 EDT 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2010.06.014· OSTI ID:21491722

Cheng, Harry C.Y. ^[1]; Wu, Vincent W.C. ^[2]; Liu, Eva S.F. ^[3]

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1. Department of Clinical Oncology, University of Hong Kong (Hong Kong)
2. Departments of Health Technology and Informatics, Hong Kong Polytechnic University (Hong Kong)
3. Department of Clinical Oncology, Queen Elizabeth Hospital (Hong Kong)

Purpose: To compare the image quality and dosimetry on the Varian cone beam computed tomography (CBCT) system between software Version 1.4.13 and Version 1.4.11 (referred to as 'new' and 'old' protocols, respectively, in the following text). This study investigated organ absorbed dose, total effective dose, and image quality of the CBCT system for the head-and-neck and pelvic regions. Methods and Materials: A calibrated Farmer chamber and two standard cylindrical Perspex CT dosimetry phantoms with diameter of 16 cm (head phantom) and 32 cm (body phantom) were used to measure the weighted cone-beam computed tomography dose index (CBCTDIw) of the Varian CBCT system. The absorbed dose of different organs was measured in a female anthropomorphic phantom with thermoluminescent dosimeters (TLD) and the total effective dose was estimated according to International Commission on Radiological Protection (ICRP) Publication 103. The dose measurement and image quality were studied for head-and-neck and pelvic regions, and comparison was made between the new and old protocols. Results: The values of the new CBCTDIw head-and-neck and pelvic protocols were 36.6 and 29.4 mGy, respectively. The total effective doses from the new head-and-neck and pelvic protocols were 1.7 and 8.2 mSv, respectively. The absorbed doses of lens for the new 200{sup o} and old 360{sup o} head-and-neck protocols were 3.8 and 59.4 mGy, respectively. The additional secondary cancer risk from daily CBCT might be up to 2.8%. Conclusions: The new Varian CBCT provided volumetric information for image guidance with acceptable image quality and lower radiation dose. This imaging tool gave a better standard for patient daily setup verification.

• OSTI ID: 21491722
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 80; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BODY
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DOSEMETERS
DOSES
ESTERS
HEAD
IMAGES
LUMINESCENT DOSEMETERS
MATERIALS
MEASURING INSTRUMENTS
MEDICINE
MOCKUP
NECK
NUCLEAR MEDICINE
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PELVIS
PERSPEX
PETROCHEMICALS
PETROLEUM PRODUCTS
PHANTOMS
PLASTICS
POLYACRYLATES
POLYMERS
POLYVINYLS
RADIATION DOSES
RADIOLOGY
RADIOTHERAPY
STRUCTURAL MODELS
SYNTHETIC MATERIALS
THERAPY
THERMOLUMINESCENT DOSEMETERS
TOMOGRAPHY