title: Tissue oxygenation in a murine SCC VII tumor after X-ray irradiation as determined by EPR spectroscopy.
abstract: OBJECTIVE
  The goal of this study was to clarify the dynamics of oxygenation (partial pressure of oxygen, pO(2)) in SCC VII murine tumors in mice after X-ray irradiation.
  
  
  METHODS
  Changes in pO(2) in tumors were measured by 1.2-GHz electron paramagnetic resonance (EPR) spectroscopy after they were exposed to various doses of irradiation. The pO(2) in tumors was followed for up to six days after irradiation at doses of 0, 5, 10, 15, and 20 Gy. 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 20 Gy). After 5 Gy, pO(2) 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 20 Gy, pO(2) increased rapidly by 6h after irradiation, continued to increase until at least 24h (P<0.01), and then gradually decreased.
  
  
  CONCLUSIONS
  In tumors that received 5 Gy, post-irradiation increases in pO(2) at 4h after irradiation were detected by EPR oximetry (P<0.01) noninvasively.
authors: School of Health Sciences, Sapporo Medical University, Sapporo, Japan.
authors: Hirotada
authors: H
authors: Fujii
authors: Koh-Ichi
authors: K
authors: Sakata
authors: Yoshihiro
authors: Y
authors: Katsumata
authors: Rikiya
authors: R
authors: Sato
authors: Makoto
authors: M
authors: Kinouchi
authors: Masanori
authors: M
authors: Someya
authors: Shin-Ichiro
authors: S
authors: Masunaga
authors: Masato
authors: M
authors: Hareyama
authors: Harold M
authors: HM
authors: Swartz
authors: Hiroshi
authors: H
authors: Hirata
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000532:radiotherapy*; D004195:Disease Models, Animal; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051379:Mice; D010092:Oximetry; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000528:radiation effects*; D010313:Partial Pressure; D014965:X-Rays / Q000009:adverse effects*
chemical_list: D010100:Oxygen