P H Van der Giessen1. 1. Dr. Bernard Verbeeten Institute for Radiation Oncology and Nuclear Medicine, Department of Clinical Physics, Tilburg, The Netherlands.
Abstract
BACKGROUND AND PURPOSE: Published data to estimate the dose outside the primary beam, i.e. the peripheral dose (PD), are only valid for perpendicularly incident beams. In radiotherapy of breast cancer patients often a tangential beam technique is used, for which the published PD data cannot be applied. MATERIAL AND METHODS: Measurements were made in a water phantom for three sizes of a breast phantom, representing a small, medium, and large breast. Open and wedged beams were used. Photon energies were 60Co gamma radiation and 6- to 25-MV X-rays. The PD was also determined in a humanoid phantom. To check the validity of the phantom measurements, the PD was measured in 50 patients referred to this institute for radiotherapy of the breast. RESULTS: The mean of the ratios of the measured to the estimated PD was 1.12, with a standard deviation of 26%. The data set was used to estimate the fetal dose for a 'standard' patient, as a function of stage of pregnancy. CONCLUSIONS: The measurements have resulted in a data set, which enables calculation of the peripheral dose for the tangential beam technique. The accuracy is considered to be adequate for risk assessment.
BACKGROUND AND PURPOSE: Published data to estimate the dose outside the primary beam, i.e. the peripheral dose (PD), are only valid for perpendicularly incident beams. In radiotherapy of breast cancerpatients often a tangential beam technique is used, for which the published PD data cannot be applied. MATERIAL AND METHODS: Measurements were made in a water phantom for three sizes of a breast phantom, representing a small, medium, and large breast. Open and wedged beams were used. Photon energies were 60Co gamma radiation and 6- to 25-MV X-rays. The PD was also determined in a humanoid phantom. To check the validity of the phantom measurements, the PD was measured in 50 patients referred to this institute for radiotherapy of the breast. RESULTS: The mean of the ratios of the measured to the estimated PD was 1.12, with a standard deviation of 26%. The data set was used to estimate the fetal dose for a 'standard' patient, as a function of stage of pregnancy. CONCLUSIONS: The measurements have resulted in a data set, which enables calculation of the peripheral dose for the tangential beam technique. The accuracy is considered to be adequate for risk assessment.
Authors: Marc D Piroth; Daniela M Piroth; Michael Pinkawa; Seth G Woodruff; Richard Holy; Michael J Eble Journal: Strahlenther Onkol Date: 2009-10-06 Impact factor: 3.621
Authors: Maria Leonardi; Agnese Cecconi; Rosa Luraschi; Elena Rondi; Federica Cattani; Roberta Lazzari; Anna Morra; Santos Soto; Vanna Zanagnolo; Viviana Galimberti; Oreste Gentilini; Fedro Peccatori; Barbara Jereczek-Fossa; Roberto Orecchia Journal: Breast Care (Basel) Date: 2017-12-13 Impact factor: 2.860