Dose distributions around selectron applicators.
Measured and calculated dose distributions around selectron applicators, loaded with 60Co high dose rate pellets, are presented. The effect of the stopping screw, spacers, pellets themselves and the applicator wall on the dose distribution is discussed. The measured dose distribution is in almost perfect agreement with the calculated distribution in planes perpendicular to the applicator axis and containing a source. On the applicator axis directly below the applicator the measured dose amounts to about 75% of the calculated value, when only the stopping screw attenuates the beam from a pellet. When the beam is attenuated by spacers in addition to the stopping screw, the discrepancy between the calculated and measured dose may exceed 50%. Clinically relevant source geometries are also discussed. It is shown that for most regions around the applicator the method of a simple addition of dose contributions from individual point sources is an acceptable approximation for the calculation of dose distributions around the selectron applicators.
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McGill University, Department of Radiation Oncology, Royal Victoria Hospital, Montréal, Québec, Canada.
Evans
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MD
Podgorsak
E B
EB
D001918:Brachytherapy / Q000295:instrumentation*; D003037:Cobalt Radioisotopes / Q000008:administration & dosage; D006801:Humans; D008962:Models, Theoretical; D011879:Radiotherapy Dosage
D003037:Cobalt Radioisotopes