Verification of dosimetric methodology for auditing radiotherapy quality under non-reference condition in Hubei province / 中华放射医学与防护杂志
Chinese Journal of Radiological Medicine and Protection
;
(12): 461-465, 2014.
Article
in Chinese
| WPRIM
| ID: wpr-453525
ABSTRACT
Objective To verify the reliability of TLD-based quality audit for radiotherapy dosimetry of medical electron accelerator in non-reference condition by monitoring the dose variations from electron beams with different field sizes and 45° wedge and the dose variations from photon beams with different field sizes and source-skin distance.Methods Both TLDs and finger ionization chambers were placed at a depth of 10 cm in water to measure the absorbed dose from photon beams,and also placed at the depth of maximum dose from electron beams under non-reference condition.TLDs were then mailed to National Institute for Radiological Protection,China CDC for further measurement.Results Among the 70 measuring points for photon beams,58 points showed the results with a relative error less than ± 7.0% (IAEA's acceptable deviation± 7.0%) between TLDs and finger ionization chambers measurements,and the percentage of qualified point numbers was 82.8%.After corrected by P,value,62 points were qualified and the percentage was up to 88.6%.All of the measuring points for electron beams,with the total number of 24,presented a relative error within ± 5.0% (IAEA's acceptable deviation± 5.0%) between TLDs and finger ioization cylindrical chambers measurements.Conclusions TLD-based quality audit is convenient for determining radiotherapy dosimetric parameters of electron beams in non-reference condition and can improve the accuracy of the measuring parameters in connection with finger chambers.For electron beams of 5 MeV < E0 < 10 MeV,the absorbed dose parameters measured by finger ionization chambers,combined with TLD audit,can help obtain the precise and reliable results.
Full text:
Available
Index:
WPRIM (Western Pacific)
Language:
Chinese
Journal:
Chinese Journal of Radiological Medicine and Protection
Year:
2014
Type:
Article
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