Computed tomography appearance of high-dose-irradiated hepatic parenchyma surrounding small tumors after stereotactic radiotherapy

Hitoshi Wada, Kenji Nemoto, Kazuhiro Majima, Shin Hitachi, Akihiro Sato, Kunihiko Tominaga, Shogo Yamada

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Introduction: The purpose of this study was to demonstrate the computed tomography (CT) appearance of high-dose-irradiated hepatic parenchyma surrounding small tumors after stereotactic radiotherapy (SRT). Materials and Methods: Thirteen patients were enrolled between September 1999 and August 2001. We treated 15 lesions [six hepatocellular carcinomas (HCC)and nine liver metastases] with SRT using a linear accelerator. We used two SRT protocols of 45 Gy/3 fractions or 60 Gy/8 fractions. Hepatic CT examinations were performed at 3- to 4-month intervals after SRT. Results: We classified the appearance of high-dose-irradiated hepatic parenchyma on CT into three types: Type 1: eight lesions (53.3%) showed low attenuation areas on non-contrast CT and high attenuation areas on contrast CT; Type 2: five lesions (33.3%) showed low attenuation areas on non-contrast and contrast CT; Type 3: two lesions (13.3%) showed no change. The CT appearance of Type 1 after SRT was similar to that of preirradiated HCC, but the other types were easily differentiated from the primary tumors. These changes were observed and continued for 6 to 22 months after treatment. In two cases of Type 1, we performed histological examinations of the regions of high attenuation on contrast CT. These specimens revealed only radiation-induced hepatic injury. Conclusion: This study showed three types of CT appearance in high-dose-irradiated hepatic parenchyma. We suggest that other examinations be considered to distinguish between radiation hepatitis and local recurrences for HCC after SRT.

Original languageEnglish
Pages (from-to)549-556
Number of pages8
JournalNippon Acta Radiologica
Volume62
Issue number10
Publication statusPublished - 2002 Sep 1
Externally publishedYes

Keywords

  • Computed Tomography
  • Liver
  • Radiation hepatitis
  • Stereotactic radiotherapy

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Oncology

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