|
Standard calibration of ionization chambers used in radiation therapy dosimetry and evaluation of uncertainties
|
A. Solimanian   , M. Ghafoori |
| , mghafoori@nrcam.org |
|
|
Abstract: (11356 Views) |
| Background: Absolute dosimetry of external
beam radiotherapy is carried out by the use of ionization
chambers. These chambers must be calibrated
at a standard dosimetry laboratory before any use in
clinical dosimetry. The secondary standard dosimetry
laboratory of Iran (SSDL) has the duty of calibrating
the ionization chambers used in radiotherapy centers
in Iran. Materials and Methods: The present work has
described traceability of SSDL radiation measurement
standards to relevant international standards,
and calibration of therapy level ionization chambers
in terms of air kerma and absorbed dose to water
against 60Co gamma radiation, as well as uncertainty
evaluation of calibration coefficients. Results: The
expanded uncertainties in the determination of air
kerma and absorbed dose to water are estimated to
be 2% and 2.3% at approximately 95% confidence
level, respectively. Conclusion: In order to maintain
the requirement of ±5% accuracy in the dose delivery,
the combined standard uncertainty of the other
factors in the dose delivery i.e., dose measurement
set-up, dose calculations, treatment planning, patient
set-up, etc, should be less than 2.3%. Iran. J. Radiat.
Res., 2010 8 (3): 195-199 |
|
| Keywords: Dosimetry, ionization chamber, calibration, uncertainty. |
|
|
Full-Text [PDF 239 kb]
(8295 Downloads)
|
|
Type of Study: Original Research |
Subject:
Radiation Biology
|
|
|
|
|
|
