Use of new radiochromic devices for peripheral dose measurement: potential in-vivo dosimetry application
- Author:
S-T Chiu-Tsao
;
MF Chan
- Publication Type:Journal Article
- Keywords:
Peripheral dose, radiochromic film, critical structures, in-vivo dosimetry
- From:Biomedical Imaging and Intervention Journal
2009;5(4):1-12
- CountryMalaysia
- Language:English
-
Abstract:
The authors have studied the feasibility of using three new high-sensitivity radiochromic devices in measuring the
doses to peripheral points outside the primary megavoltage photon beams. The three devices were GAFCHROMIC®
EBT film, prototype Low Dose (LD) Film, and prototype LD Card. The authors performed point dosimetry using these
three devices in water-equivalent solid phantoms at x = 3,5,8,10, and 15 cm from the edge of 6 MV and 15 MV photon
beams of 10x10 cm2, and at depths of 0, 0.5 cm, and depth of maximum dose. A full sheet of EBT film was exposed
with 5000 MU. The prototype LD film pieces were 1.5x2 cm2 in size. Some LD films were provided in the form of a
card in 1.8x5 cm2 holding an active film in 1.8x2 cm2. These are referred to as “LD dosimeter cards”. The small LD
films and cards were exposed with 500 MU. For each scanned film, a 6 mm circular area centered at the measurement
point was sampled and the mean pixel value was obtained. The calibration curves were established from the calibration data for each combination of film/cards and densitometer/scanner. The doses at the peripheral points determined from the films were compared with those obtained using ion chamber at respective locations in a water phantom and general agreements were found. It is feasible to accurately measure peripheral doses of megavoltage photon beams using the
new high-sensitivity radiochromic devices. This near real-time and inexpensive method can be applied in a clinical
setting for dose measurements to critical organs and sensitive patient implant devices.
- Full text:W020150910527251180684.pdf
