Format

Send to

Choose Destination
Med Dosim. 2010 Winter;35(4):324-9. doi: 10.1016/j.meddos.2009.10.007. Epub 2010 Jan 22.

Evaluation of a 3D diode array dosimeter for helical tomotherapy delivery QA.

Author information

1
Moffitt Cancer Center, Tampa, FL, USA. vladimir.feygelman@moffitt.org

Abstract

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°. 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 γ(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.

PMID:
20097061
DOI:
10.1016/j.meddos.2009.10.007
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center