Evaluation of a 3D Diode Array Dosimeter for Helical Tomotherapy Delivery QA
- Moffitt Cancer Center, Division of Radiation Oncology, Tampa, FL (United States)
The Delta4 biplanar diode array dosimeter was validated for helical tomotherapy delivery QA. The basic detector characteristics were found to be satisfactory in terms of short-term reproducibility (0.1%), linearity (<0.1%), dose rate dependence (0.4%), and absolute calibration accuracy (0.4% in the center of the phantom compared with the independently calibrated diode). Relative calibration of the arrays was verified by comparison with film and by rotating the detector 180{sup o}. The dosimeter response to rotational irradiation changed by no more than 0.2% when one of the detector boards was replaced by the homogeneous phantom material. The daily output correction factor can be derived from a Delta4 measurement in a uniform cylindrical field. The {gamma}(3%, 3 mm) passing rate (absolute dose) was above 90% for all 9 evaluated clinical plans, and above 96% for all but one. The mean passing rate was 97 {+-} 2.7%. The plans varied in modulation factor, pitch, and calculation grid size. For best results, the phantom needs to be aligned carefully, preferably by megavoltage computed tomography imaging.
- OSTI ID:
- 21486877
- Journal Information:
- Medical Dosimetry, Vol. 35, Issue 4; Other Information: DOI: 10.1016/j.meddos.2009.10.007; PII: S0958-3947(09)00126-5; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0958-3947
- Country of Publication:
- United States
- Language:
- English
Similar Records
Optimizing the accuracy of a helical diode array dosimeter: A comprehensive calibration methodology coupled with a novel virtual inclinometer
SU-E-T-374: Sensitivity of ArcCHECK to Tomotherapy Delivery Errors: Dependence On Analysis Technique
Related Subjects
61 RADIATION PROTECTION AND DOSIMETRY
CALIBRATION
CT-GUIDED RADIOTHERAPY
DOSE RATES
DOSEMETERS
QUALITY ASSURANCE
SILICON DIODES
THREE-DIMENSIONAL CALCULATIONS
MEASURING INSTRUMENTS
MEDICINE
NUCLEAR MEDICINE
RADIOLOGY
RADIOTHERAPY
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
THERAPY