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Radiation dose distribution under the area protected using a Cerrobend block during external beam radiotherapy: a film study

Published online by Cambridge University Press:  03 April 2014

Mohammad Mohammadi ,
Amir Taherkhani  and
Mohmmadsaeed Saboori
Mohammad Mohammadi*
Affiliation:
Department of Medical Physics, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Department of Medical Physics, Royal Adelaide Hospital, Adelaide, 5000 South Australia, Australia
Amir Taherkhani
Affiliation:
Department of Proteomics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Department of Microbiology, Islamic Azad University, Hamadan, Iran
Mohmmadsaeed Saboori
Affiliation:
University Hospitals of Erlangen, Radiation Oncology, Erlangen, Germany
*
Correspondence to: Mohammad Mohammadi, Department of Medical Physics, Faculty of Medicine, Hamadan University of Medical Sciences, 65178-38678 Hamadan, Iran. Tel: +98 8381037; Fax: +98 8381017. E-mail: Mohammadi@umsha.ac.ir
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Abstract

Background

In radiation therapy, to spare normal surrounding tissues, either Multileaf Collimators or Cerrobend blocks are used.

Purpose

The current study focuses on the relative dose distribution under the areas protected by Cerrobend blocks.

Materials and methods

A dual-energy linear accelerator and a Cobalt-60 machine were utilised as radiation sources. Several blocks were designed using commercially available materials to shield radiation fields. The relative dose distribution was then evaluated using extended dose range 2 films.

Results

Results showed that the dose distribution under protected areas depends on several parameters including the width and height of protecting blocks, incident photon beam energy, radiation field size and source to surface distance. An increase in Cerrobend block height from 80 to 95 mm significantly decreases the dose at the protected areas.

Conclusion

An increase in the block width and photon energy decreases the relative dose deposition at the protected area. However, electron and neutron contaminations should also be taken into consideration.

Keywords

Cerrobend blocksdose distributionfilm dosimetryradiation protection
Type
Original Articles
Information
Journal of Radiotherapy in Practice , Volume 13 , Issue 4 , December 2014 , pp. 456 - 464
Copyright
Copyright © Cambridge University Press 2014 

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