Development and Clinical Implementation of a Universal Bolus to Maintain Spot Size During Delivery of Base of Skull Pencil Beam Scanning Proton Therapy

被引：35

作者：

Both, Stefan ^{[1
]}

Shen, Jiajian ^{[1
,2
]}

Kirk, Maura ^{[1
]}

Lin, Liyong ^{[1
]}

Tang, Shikui ^{[1
]}

Alonso-Basanta, Michelle ^{[1
]}

Lustig, Robert ^{[1
]}

Lin, Haibo ^{[1
]}

Deville, Curtiland ^{[1
]}

Hill-Kayser, Christine ^{[1
]}

Tochner, Zelig ^{[1
]}

McDonough, James ^{[1
]}

机构：

[1] Univ Penn, Dept Radiat Oncol, Philadelphia, PA 19104 USA

[2] Mayo Clin, Dept Radiat Oncol, Phoenix, AZ USA

来源：

INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS | 2014年 / 90卷 / 01期

关键词：

D O I：

10.1016/j.ijrobp.2014.05.005

中图分类号：

R73 [肿瘤学];

学科分类号：

100214 ;

摘要：

Purpose: To report on a universal bolus (UB) designed to replace the range shifter (RS); the UB allows the treatment of shallow tumors while keeping the pencil beam scanning (PBS) spot size small. Methods and Materials: Ten patients with brain cancers treated from 2010 to 2011 were planned using the PBS technique with bolus and the RS. In-air spot sizes of the pencil beam were measured and compared for 4 conditions (open field, with RS, and with UB at 2- and 8-cm air gap) in isocentric geometry. The UB was applied in our clinic to treat brain tumors, and the plans with UB were compared with the plans with RS. Results: A UB of 5.5 cm water equivalent thickness was found to meet the needs of the majority of patients. By using the UB, the PBS spot sizes are similar with the open beam (P>.1). The heterogeneity index was found to be approximately 10% lower for the UB plans than for the RS plans. The coverage for plans with UB is more conformal than for plans with RS; the largest increase in sparing is usually for peripheral organs at risk. Conclusions: The integrity of the physical properties of the PBS beam can be maintained using a UB that allows for highly conformal PBS treatment design, even in a simple geometry of the fixed beam line when noncoplanar beams are used. (C) 2014 Published by Elsevier Inc.

引用

页码：79 / 84

页数：6