Dosimetric calibration of CT pencil chamber in cobalt beams.
- Author:
Yi LI
;
Junliang WANG
;
Yunlai WANG
- Publication Type:Journal Article
- MeSH: Calibration; Radiation Monitoring; methods; Radiation, Ionizing; Radiometry; Tomography, X-Ray Computed; instrumentation
- From: Chinese Journal of Medical Instrumentation 2014;38(1):76-78
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo explore the dose-length product calibration method for pencil ionization chamber in cobalt beams.
METHODSThe PTW TM30009 ionization chamber was placed into the central hole of T40017 head phantom and irradiated 60 s in 20 cm x 20 cm cobalt beam. The charge was collected with UNIDOS electrometer. Absorbed doses were measured with TM30013 0.6 mL farmer-type chamber under the same condition. The CT chamber calibration factor was expressed in dose-length product. Dose linearity and spatial response were also investigated.
RESULTSThe calibration factor in dose-length product was derived from measured data. Dose linearity and spatial response were good in cobalt beams.
CONCLUSIONIt is feasible to calibrate the CT chamber in cobalt beams for patient dose evaluation in MVCT.