A feasibility study of Fricke dosimetry as an absorbed dose to water standard for 192Ir HDR sources.

High dose rate brachytherapy (HDR) using 192Ir sources is well accepted as an important treatment option and thus requires an accurate dosimetry standard. However, a dosimetry standard for the direct measurement of the absolute dose to water for this particular source type is currently not available. An improved standard for the absorbed dose to water based on Fricke dosimetry of HDR 192Ir brachytherapy sources is presented in this study.

Chemotherapy and radiation regimens to breast cancer treatment induce changes in mRNA levels of renin-angiotensin system related genes in cardiac tissue.

Background And Aim: Cardiovascular complications are one limitation of breast cancer treatment. The aim of the current study was to investigate whether the renin-angiotensin related genes could be altered by chemotherapy and radiotherapy, using a rat model.

Methods: Female rats were divided into three groups: control, chemotherapy + irradiation (TC+IR) and irradiation (IR).

Up-regulation of angiotensin-converting enzyme and angiotensin II type 1 receptor in irradiated rats.

Purpose: To investigate changes in cardiac functional parameters and the cardiac expression of angiotensin-converting enzyme (ACE), angiotensin II type 1 receptor (AT1), procollagen type I (proc-I) and transforming growth factor-ß1 (TGF-ß1) in rats irradiated at heart.

Material And Methods: Male Wistar rats were irradiated with a single dose of radiation (0, 5, 10 and 15 Gray [Gy]) delivered directly to the heart and the molecular evaluations were performed at various times post-irradiation (two days, 15 days and four months). The expression of ACE, AT1, proc-I and TGF-ß1 were analysed using Real Time-Polymerase Chain Reaction (RT-PCR) and/or Western blotting.

Air kerma standard for calibration of well-type chambers in Brazil using 192Ir HDR sources and its traceability.

In Brazil there are over 100 high dose rate (HDR) brachytherapy facilities using well-type chambers for the determination of the air kerma rate of 192Ir sources. This paper presents the methodology developed and extensively tested by the Laboratorio de Ciencias Radiologicas (LCR) and presently in use to calibrate those types of chambers. The system was initially used to calibrate six well-type chambers of brachytherapy services, and the maximum deviation of only 1.