Medical Dosimetry
Volume 36, Issue 1 , Pages 10-13, Spring 2011

A Low-Dose Ipsilateral Lung Restriction Improves 3-D Conformal Planning for Partial Breast Radiation Therapy

Presented in part at the 2007 Canadian Association of Radiation Oncology Annual Meeting, October 9–13, 2007, Toronto, Ontario, Canada.

Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre, University of British Columbia, University of Victoria, Victoria, British Columbia, Canada

Received 15 December 2008; accepted 21 October 2009. published online 25 January 2010.

Abstract 

In trials of 3D conformal external beam partial breast radiotherapy (PBRT), the dosimetrist must balance the priorities of achieving high conformity to the target versus minimizing low-dose exposure to the normal structures. This study highlights the caveat that in the absence of a low-dose lung restriction, the use of relatively en-face fields may meet trial-defined requirements but expose the ipsilateral lung to unnecessary low-dose radiation. Adding a low-dose restriction that ≤20% of the ipsilateral lung should receive 10% of the prescribed dose resulted in successful plans in 88% of cases. This low-dose lung limit should be used in PBRT planning.

Key Words: Partial breast irradiation, Treatment planning, Dose restriction, Lung exposure, Secondary malignancies

 

PII: S0958-3947(09)00122-8

doi:10.1016/j.meddos.2009.10.003

Medical Dosimetry
Volume 36, Issue 1 , Pages 10-13, Spring 2011