Stereotactic body radiation therapy planning for liver tumors using functional images from dual-energy computed tomography

Shingo Ohira; Naoyuki Kanayama; Masayasu Toratani; Yoshihiro Ueda; Yuhei Koike; Tsukasa Karino; Ono Shunsuke; Masayoshi Miyazaki; Masahiko Koizumi; Teruki Teshima

doi:10.1016/j.radonc.2019.12.002

Stereotactic body radiation therapy planning for liver tumors using functional images from dual-energy computed tomography

Radiother Oncol. 2020 Apr:145:56-62. doi: 10.1016/j.radonc.2019.12.002. Epub 2020 Jan 7.

Authors

Affiliations

¹ Department of Radiation Oncology, Osaka International Cancer Institute, Japan; Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan. Electronic address: oohira-si@mc.pref.osaka.jp.
² Department of Radiation Oncology, Osaka International Cancer Institute, Japan.
³ Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan.
⁴ Department of Radiation Oncology, Osaka International Cancer Institute, Japan; Department of Radiology, Hyogo College of Medicine, Hyogo, Japan.
⁵ Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan.

PMID: 31923710
DOI: 10.1016/j.radonc.2019.12.002

Abstract

Purpose: This study aimed to generate a functional image of the liver using dual-energy computed tomography (DECT) and a functional-image-based stereotactic body radiation therapy plan to minimize the dose to the volume of the functional liver (V_fl).

Material and methods: A normalized iodine density (NID) map was generated for fifteen patients with liver tumors. The volume of liver with an NID < 0.46 was defined as V_fl, and the ratio between V_fl and the total volume of the liver (FLR) was calculated. The relationship between the FLR and Fibrosis-4 (FIB-4) was assessed. For patients with 15% < FLR < 85%, functional volumetric modulated-arc therapy plans (F-VMAT) were retrospectively generated to preserve V_fl, and compared to the clinical plans (C-VMAT).

Results: FLR showed a significantly strong correlation with FIB-4 (r = -0.71, p < 0.01). For ten generated F-VMAT plans, the dosimetric parameters of D_99%, D_50%, D_1% and the conformity index were comparable to those of the C-VMAT (p > 0.05). For V_fl, F-VMAT plans achieved lower V_5Gy (122.4 ± 31.7 vs 181.1 ± 57.3 cc), V_10Gy (44.4 ± 22.2 vs 98.2 ± 33.3 cc), V_15Gy (22.6 ± 20.3 vs 49.8 ± 33.7 cc), V_20Gy (11.6 ± 14.1 vs 24.9 ± 25.1 cc), and D_mean (3.9 ± 2.3 vs 5.8 ± 3.0 Gy) values than the C-VMAT plans (p < 0.01).

Conclusions: The functional image derived from DECT was successfully used, allowing for a reduction in the dose to the V_fl without compromising target coverage.

Keywords: DECT; Fibrosis; Function; Liver; SBRT.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Humans
Liver Neoplasms* / diagnostic imaging
Liver Neoplasms* / radiotherapy
Radiosurgery*
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted
Radiotherapy, Intensity-Modulated*
Retrospective Studies
Tomography