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Title: Backscatter Correction Algorithm for TBI Treatment Conditions

Abstract

The accuracy requirements in target dose delivery is, according to ICRU, ±5%. This is so not only in standard radiotherapy but also in total body irradiation (TBI). Physical dosimetry plays an important role in achieving this recommended level. The semi-infinite phantoms, customarily used for dosimetry purposes, give scatter conditions different to those of the finite thickness of the patient. So dose calculated in patient’s points close to beam exit surface may be overestimated. It is then necessary to quantify the backscatter factor in order to decrease the uncertainty in this dose calculation. The backward scatter has been well studied at standard distances. The present work intends to evaluate the backscatter phenomenon under our particular TBI treatment conditions. As a consequence of this study, a semi-empirical expression has been derived to calculate (within 0.3% uncertainty) the backscatter factor. This factor depends lineally on the depth and exponentially on the underlying tissue. Differences found in the qualitative behavior with respect to standard distances are due to scatter in the bunker wall close to the measurement point.

Authors:
; ; ;  [1];  [2]
  1. Dpto. Fisiología Médica y Biofísica, Universidad de Sevilla, Avda. Sánchez Pizjuán, 4. E-41009, Sevilla (Spain)
  2. Servicio Oncología Radioterápica, Hospital Univ.V. Macarena. Dr. Fedriani, s/n. E-41009, Sevilla (Spain)
Publication Date:
OSTI Identifier:
22577821
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Dosimetry; Journal Volume: 18; Journal Issue: 3; Other Information: Copyright (c) 1993 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; 62 RADIOLOGY AND NUCLEAR MEDICINE; ACCURACY; ALGORITHMS; CORRECTIONS; DOSIMETRY; PATIENTS; PHANTOMS; RADIATION DOSES; RADIOTHERAPY; THICKNESS; WHOLE-BODY IRRADIATION

Citation Formats

Sanchez-Nieto, B., Sanchez-Doblado, F., Arrans, R., Terron, J.A., and Errazquin, L. Backscatter Correction Algorithm for TBI Treatment Conditions. United States: N. p., 2015. Web. doi:10.1016/S0958-3947(06)80003-8.
Sanchez-Nieto, B., Sanchez-Doblado, F., Arrans, R., Terron, J.A., & Errazquin, L. Backscatter Correction Algorithm for TBI Treatment Conditions. United States. doi:10.1016/S0958-3947(06)80003-8.
Sanchez-Nieto, B., Sanchez-Doblado, F., Arrans, R., Terron, J.A., and Errazquin, L. Thu . "Backscatter Correction Algorithm for TBI Treatment Conditions". United States. doi:10.1016/S0958-3947(06)80003-8.
@article{osti_22577821,
title = {Backscatter Correction Algorithm for TBI Treatment Conditions},
author = {Sanchez-Nieto, B. and Sanchez-Doblado, F. and Arrans, R. and Terron, J.A. and Errazquin, L.},
abstractNote = {The accuracy requirements in target dose delivery is, according to ICRU, ±5%. This is so not only in standard radiotherapy but also in total body irradiation (TBI). Physical dosimetry plays an important role in achieving this recommended level. The semi-infinite phantoms, customarily used for dosimetry purposes, give scatter conditions different to those of the finite thickness of the patient. So dose calculated in patient’s points close to beam exit surface may be overestimated. It is then necessary to quantify the backscatter factor in order to decrease the uncertainty in this dose calculation. The backward scatter has been well studied at standard distances. The present work intends to evaluate the backscatter phenomenon under our particular TBI treatment conditions. As a consequence of this study, a semi-empirical expression has been derived to calculate (within 0.3% uncertainty) the backscatter factor. This factor depends lineally on the depth and exponentially on the underlying tissue. Differences found in the qualitative behavior with respect to standard distances are due to scatter in the bunker wall close to the measurement point.},
doi = {10.1016/S0958-3947(06)80003-8},
journal = {Medical Dosimetry},
number = 3,
volume = 18,
place = {United States},
year = {Thu Jan 15 00:00:00 EST 2015},
month = {Thu Jan 15 00:00:00 EST 2015}
}