Tissue oxygenation in a murine SCC VII tumor after X-ray irradiation as determined by EPR spectroscopy

Fujii, Hirotada; Sakata, Koh-ichi; Katsumata, Yoshihiro; Sato, Rikiya; Kinouchi, Makoto; Someya, Masanori; Masunaga, Shin-ichiro; Hareyama, Masato; Swartz, Harold M.; Hirata, Hiroshi

doi:10.1016/j.radonc.2007.11.020

« Previous Next »Radiotherapy & Oncology
Volume 86, Issue 3 , Pages 354-360, March 2008

Tissue oxygenation in a murine SCC VII tumor after X-ray irradiation as determined by EPR spectroscopy

Hirotada Fujii
- School of Health Sciences and
Koh-ichi Sakata
- Department of Radiology, Sapporo Medical University, Sapporo, Japan
Yoshihiro Katsumata
- Graduate Program of Human Sensing and Functional Sensor Engineering, and
Rikiya Sato
- Graduate Program of Human Sensing and Functional Sensor Engineering, and
Makoto Kinouchi
- Department of Bio-System Engineering, Yamagata University, Yonezawa, Japan
Masanori Someya
- Department of Radiology, Sapporo Medical University, Sapporo, Japan
Shin-ichiro Masunaga
- Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, Osaka, Japan
Masato Hareyama
- Department of Radiology, Sapporo Medical University, Sapporo, Japan
Harold M. Swartz
- EPR Center for Viable Systems, Department of Radiology, Dartmouth Medical School, Hanover, NH, USA
Hiroshi Hirata
- Graduate Program of Human Sensing and Functional Sensor Engineering, and
- Department of Electrical Engineering, Yamagata University, Yonezawa, Japan
- Corresponding author. Hiroshi Hirata, Department of Electrical Engineering, Yamagata University, Yonezawa, Yamagata 992-8510, Japan.

Received 3 July 2007; received in revised form 19 November 2007; accepted 19 November 2007. published online 12 December 2007.

Abstract

Purpose

The goal of this study was to clarify the dynamics of oxygenation (partial pressure of oxygen, pO₂) in SCC VII murine tumors in mice after X-ray irradiation.

Materials and methods

Changes in pO₂ in tumors were measured by 1.2-GHz electron paramagnetic resonance (EPR) spectroscopy after they were exposed to various doses of irradiation. The pO₂ in tumors was followed for up to six days after irradiation at doses of 0, 5, 10, 15, and 20Gy. Paramagnetic crystals were used as an oximetry probe and implanted into normal or tumor tissues in mice for prolonged periods.

Results

The pattern of tumor oxygen after a single dose of radiation with the 5-Gy dose was different from those with other doses (10, 15, and 20Gy). After 5Gy, pO₂ increased rapidly (P<0.01, Student’s t test) and then returned to the level observed before irradiation by 12h (P<0.01). In contrast, after 10, 15, or 20Gy, pO₂ increased rapidly by 6h after irradiation, continued to increase until at least 24h (P<0.01), and then gradually decreased.