Dosimetric comparison of CT-guided iodine-125 seed stereotactic brachytherapy and stereotactic body radiation therapy in the treatment of NSCLC.

Ranran Li,Jianjian Dai,Mingyong Han,Ruicai Xu,Ying Zhang,Xudong Hu,Yuan Yuan,Qi Lin,Gabriele Multhoff

doi:10.1371/journal.pone.0187390

Abstract

This study aimed to assess the dosimetric differences between iodine-125 seed stereotactic brachytherapy (SBT) and stereotactic body radiation therapy (SBRT) in the treatment of non-small cell lung cancer (NSCLC). An SBT plan and an SBRT plan were generated for eleven patients with T1-2 NSCLC. Prescription of the dose and fractionation (fr) for SBRT was 48Gy/4fr. The planning aim for SBT was D90 (dose delivered to 90% of the target volume)≥120Gy. Student’s paired t test was used to compare the dosimetric parameters. The SBT and SBRT plans had comparable PTV D90 (104.73±2.10Gyvs.107.64±2.29Gy), and similar mean volume receiving 100% of the prescription dose (V100%) (91.65% vs.92.44%, p = 0.410). The mean volume receiving 150% of the prescribed dose (V150%) for SBT was 64.71%, whereas it was 0% for SBRT. Mean heterogeneity index (HI) deviation for SBT vs. SBRT was 0.73 vs. 0.19 (p<0.0001), and the mean conformity index (CI) for SBT vs. SBRT was 0.77 vs. 0.81 (p = 0.031). The mean lung doses (MLD) in SBT were significantly lower than those in SBRT (1.952±0.713 vs. 5.618±2.009, p<0.0001). In conclusion, compared with SBRT, SBT can generate a comparable dose within PTV, while the organs at risk (OARs) only receive a very low dose. But the HI and CI in SBT were lower than in SBRT.

Highlights

Lung cancer is the leading cause of cancer death in China[1]
Prescription doses for Stereotactic body radiation therapy (SBRT) and stereotactic brachytherapy (SBT) were 48Gy and 120Gy respectively
To compare different treatment plans, doses were converted to the biologically equivalent dose (BED) with an α/β ratio of 10Gy for planning target volume (PTV)

Summary

Introduction

Surgery is usually the standard option for the treatment of localized cancers, but not all patients with operable non-small cell lung cancer (NSCLC) are candidates for surgery[2]. Stereotactic body radiation therapy (SBRT), which delivers an ablative dose of radiation over a short period of time, has emerged to become a major noninvasive option for the treatment of early stage NSCLC[3,4,5,6,7]. This therapy is noninvasive and well-studied, and has high local control rates.

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Conclusion