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Updated: Apr 29, 2026
Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator
Published on: May 9, 2014
[Dosimetric calibration of CT pencil chamber in cobalt beams]
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 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.
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.
