title: 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.
abstract: 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).
authors.affiliation: SSDL, Metrology Department, ININ, P.O. BOX 18-1027 11801, Mexico City, Mexico. jtar@nuclear.inin.mx
authors.forename: J T
authors.initials: JT
authors.lastname: Alvarez Romero
authors.forename: V M
authors.initials: VM
authors.lastname: Tovar Muñoz
authors.forename: B Salinas
authors.initials: BS
authors.lastname: de León
authors.forename: J O Hernández
authors.initials: JO
authors.lastname: Oviedo
authors.forename: L Santillán
authors.initials: LS
authors.lastname: Barcenas
authors.forename: C Molero
authors.initials: CM
authors.lastname: Milo
authors.forename: J Montoya
authors.initials: JM
authors.lastname: Monterrubio
mesh_terms: 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
chemical_list: D002588:Cesium Radioisotopes; D014867:Water