An evaluation of planning techniques for stereotactic body radiation therapy in lung tumors

Wu, Jianzhou; Li, Huiling; Shekhar, Raj; Suntharalingam, Mohan; D’Souza, Warren

doi:10.1016/j.radonc.2008.02.010

« Previous Next »Radiotherapy & Oncology
Volume 87, Issue 1 , Pages 35-43, April 2008

An evaluation of planning techniques for stereotactic body radiation therapy in lung tumors☆

Jianzhou Wu
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Diagnostic Radiology, University of Maryland School of Medicine, Baltimore, MD, USA
Huiling Li
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
Raj Shekhar
- Department of Diagnostic Radiology, University of Maryland School of Medicine, Baltimore, MD, USA
Mohan Suntharalingam
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
Warren D’Souza
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
- Corresponding author. Warren D’Souza, Department of Radiation Oncology, University of Maryland School of Medicine, 22 South Greene Street, Baltimore, MD 21201, USA.

Received 5 October 2007; received in revised form 8 February 2008; accepted 10 February 2008. published online 25 March 2008.

Abstract

Purpose

To evaluate four planning techniques for stereotactic body radiation therapy (SBRT) in lung tumors.

Methods and materials

Four SBRT plans were performed for 12 patients with stage I/II non-small-cell lung cancer under the following conditions: (1) conventional margins on free-breathing CT (plan 1), (2) generation of an internal target volume (ITV) using 4DCT with beam delivery under free-breathing conditions (plan 2), (3) gating at end-exhale (plan 3), and (4) gating at end-inhale (plan 4). Planning was performed following the RTOG 0236 protocol with a prescription dose of 54Gy (3 fractions). For each plan 4D dose was calculated using deformable-image registration.

Results

There was no significant difference in tumor dose delivered by the 4 plans. However, compared with plan 1, plans 2–4 reduced total lung BED by 1.9±1.2, 3.1±1.6 and 3.5±2.1Gy, reduced mean lung dose by 0.8±0.5, 1.5±0.8, and 1.6±1.0Gy, reduced V20 by 1.5±1.0%, 2.7±1.4%, and 2.8±1.8%, respectively, with p<0.01. Compared with plan 2, plans 3–4 reduced lung BED by 1.2±1.0 and 1.6±1.5Gy, reduced mean lung dose by 0.6±0.5 and 0.8±0.7Gy, reduced V20 by 1.2±1.1% and 1.3±1.5%, respectively, with p<0.01. The differences in lung BED, mean dose and V20 of plan 4 compared with plan 3 were insignificant.

Conclusions

Tumor dose coverage was statistically insignificant between all plans. However, compared with plan 1, plans 2–4 significantly reduced lung doses. Compared with plan 2, plan 3–4 also reduced lung toxicity. The difference in lung doses between plan 3 and plan 4 was not significant.

Keywords: Image registration, 4D dose, SBRT, Lung tumor