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Improvement of dose homogeneity with irregular surface compensator in whole brain radiotherapy

Published online by Cambridge University Press:  02 May 2016

H. Fujita ,
N. Kuwahata ,
H. Hattori ,
H. Kinoshita  and
H. Fukuda
H. Fujita*
Affiliation:
Department of Radiation Oncology, Osaka Saiseikai Nakatsu Hospital, Kita-ku, Osaka, Japan
N. Kuwahata
Affiliation:
Department of Radiation Oncology, Osaka Saiseikai Nakatsu Hospital, Kita-ku, Osaka, Japan
H. Hattori
Affiliation:
Department of Radiation Oncology, Osaka Saiseikai Nakatsu Hospital, Kita-ku, Osaka, Japan
H. Kinoshita
Affiliation:
Department of Radiation Oncology, Osaka Saiseikai Nakatsu Hospital, Kita-ku, Osaka, Japan
H. Fukuda
Affiliation:
Department of Radiation Oncology, Osaka Saiseikai Nakatsu Hospital, Kita-ku, Osaka, Japan
*
Correspondence to: Hideki Fujita, Department of Radiation Oncology, Osaka Saiseikai Nakatsu Hospital, 2-10-39 Shibata, Kita-ku, Osaka 580-0012, Japan. Tel: 81(6)6372-0333. Fax: 81(6)6105-1360. E-mail: hima71f@zeus.eonet.ne.jp
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Abstract

Purpose

The aim of this study was to evaluate the dosimetric aspects of whole brain radiotherapy (WBRT) using an irregular surface compensator (ISC) in contrast to conventional radiotherapy techniques.

Methods

Treatment plans were devised for 20 patients. The Eclipse treatment planning system (Varian Medical Systems) was used for dose calculation. For the ISC, a fluence editor application was used to extend the range of optimal fluence. The treatment plan with the ISC was compared with the conventional technique in terms of doses in the planning target volume (PTV), dose homogeneity index (DHI), three-dimensional (3D) maximum dose, eye and lens doses and monitor unit (MU) counts required for treatment.

Results

Compared with conventional WBRT, the ISC significantly reduced the DHI, 3D maximum dose and volumes receiving 105% of the prescription dose, in addition to reducing both eye and lens doses (p<0·05 for all comparisons). In contrast, MU counts were higher for the ISC technique than for conventional WBRT (828 versus 328, p<0·01).

Conclusion

The ISC technique for WBRT considerably improved the dose homogeneity in the PTV. As patients who receive WBRT have improved survival, the long-term side effects of radiotherapy are highly important.

Keywords

dose homogeneity indexfluence editorirregular surface compensatormultileaf collimatorwhole brain radiotherapy
Type
Original Articles
Information
Journal of Radiotherapy in Practice , Volume 15 , Issue 3 , September 2016 , pp. 269 - 275
Copyright
© Cambridge University Press 2016 

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