Dosimetric Calibration of CT Pencil Chamber in Cobalt Beams
10.3969/j.issn.1671-7104.2014.01.023
- VernacularTitle:用60Co射线校准CT电离室的研究
- Author:
Yi LI
1
;
Junliang WANG
;
Yunlai WANG
Author Information
1. 解放军总医院放疗科
- Keywords:
dosimetry;
CT dose index;
pencil chamber;
absorbed dose
- From:
Chinese Journal of Medical Instrumentation
2014;(1):76-78
- CountryChina
- Language:Chinese
-
Abstract:
Objective To explore the dose-length product calibration method for pencil ionization chamber in cobalt beams. Methods The PTW TM30009 ionization chamber was placed into the central hole of T40017 head phantom and irradiated 60 s in 20 cm×20 cm cobalt beam. The charge was col ected 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. Results The calibration factor in dose-length product was derived from measured data. Dose linearity and spatial response were good in cobalt beams. Conclusion It is feasible to calibrate the CT chamber in cobalt beams for patient dose evaluation in MVCT.
