Calibration of a TLD-100 powder dosimetric system to verify the absorbed dose to water imparted by 137Cs sources in low dose rate brachytherapy at the oncology unit in the Hospital General de Mexico.
A thermoluminescence dosimetry (TLD) system was characterised at SSDL-ININ to verify the air-kerma strength (S(K)) and dose-to-water (D(W)) values for (137)Cs sources used in low dose rate (LDR) brachytherapy treatments at the Hospital General de Mexico (HGM). It consists of a Harshaw 3500 reader and a set of TLD-100 powder capsules. The samples of TLD-100 powder were calibrated in terms of D(W) vs. nC or nC mg(-1), and their dose response curves were corrected for supralinearity. The D(W) was calculated using the AAPM TG-43 formalism using S(K) for a CDCSM4 (137)Cs reference source. The S(K) value was obtained by using a NE 2611 chamber, and with two well chambers. The angular anisotropy factor was measured with the NE 2611 chamber for this source. The HGM irradiated TLD-100 powder capsules to a reference dose D(W) of 2 Gy with their (137)Cs sources. The percent deviations between the imparted and reference doses were 1.2% < or = Delta < or = 6.5%, which are consistent with the combined uncertainties: 5.6% < or = u(c) < or = 9.8% for D(W).
Alvarez Romero
J T
JT
SSDL, Metrology Department, ININ, P.O. BOX 18-1027 11801, Mexico City, Mexico. jtar@nuclear.inin.mx
Tovar Muñoz
V M
VM
de León
B Salinas
BS
Oviedo
J O Hernández
JO
Barcenas
L Santillán
LS
Milo
C Molero
CM
Monterrubio
J Montoya
JM
D001822:Body Burden; D001918:Brachytherapy / Q000379:methods / Q000592:standards*; D002588:Cesium Radioisotopes / Q000032:analysis* / Q000627:therapeutic use*; D008800:Mexico; D011879:Radiotherapy Dosage; D012016:Reference Values; D012062:Relative Biological Effectiveness; D013819:Thermoluminescent Dosimetry / Q000379:methods* / Q000592:standards*; D014867:Water
D002588:Cesium Radioisotopes; D014867:Water