TY - JOUR
T1 - Monte Carlo and analytic calculation of absorbed dose near 137CS intracavitary sources
AU - Williamson, Jeffrey F.
PY - 1988/7
Y1 - 1988/7
N2 - This paper presents dose-rate tables and treatment planning data needed to accurately implement the Sievert line-source integral, found on most commercial computer-aided treatment planning systems, for two recently introduced 137CS intracavitary sources. One source uses a high-density active core designed to reproduce the non-elliptical isodose curves characteristic of the traditional radium tube. The other source consists of two or three discrete 137CS seeds encapsulated in stainless steel. Using Monte Carlo dose-rate calculations as the standard of accuracy, we show that the Sievert model, using conventionally defined filtration corrections, overestimates kerma-rate in free space by as much as 20%. In addition, tissue attenuation and scatter build-up factors, derived from an isotropic point source, do not accurately characterize the distribution of scatter dose about heavily filtered sources. By varying the input parameters of the Sievert line-source integral so as to optimize its agreement with the more rigorous Monte Carlo data, accuracy of 3% can be achieved.
AB - This paper presents dose-rate tables and treatment planning data needed to accurately implement the Sievert line-source integral, found on most commercial computer-aided treatment planning systems, for two recently introduced 137CS intracavitary sources. One source uses a high-density active core designed to reproduce the non-elliptical isodose curves characteristic of the traditional radium tube. The other source consists of two or three discrete 137CS seeds encapsulated in stainless steel. Using Monte Carlo dose-rate calculations as the standard of accuracy, we show that the Sievert model, using conventionally defined filtration corrections, overestimates kerma-rate in free space by as much as 20%. In addition, tissue attenuation and scatter build-up factors, derived from an isotropic point source, do not accurately characterize the distribution of scatter dose about heavily filtered sources. By varying the input parameters of the Sievert line-source integral so as to optimize its agreement with the more rigorous Monte Carlo data, accuracy of 3% can be achieved.
KW - Cs
KW - Dosimetry
KW - Intracavitary brachytherapy
KW - Monte Carlo simulation
UR - http://www.scopus.com/inward/record.url?scp=0023788640&partnerID=8YFLogxK
U2 - 10.1016/0360-3016(88)90372-0
DO - 10.1016/0360-3016(88)90372-0
M3 - Article
C2 - 3391820
AN - SCOPUS:0023788640
SN - 0360-3016
VL - 15
SP - 227
EP - 237
JO - International journal of radiation oncology, biology, physics
JF - International journal of radiation oncology, biology, physics
IS - 1
ER -