Differences in pO2 Peaks of a Murine Fibrosarcoma between Carbon-ion and X-ray Irradiation

Takeshi FUKAWA, Koji TAKEMATSU, Kotaro OKA, Sachiko KOIKE, Koichi ANDO, Hirosuke KOBAYASHI, Kazuo TANISHITA
2004 Journal of Radiation Research  
pO2 profile/Reoxygenation/HIMAC/Fibrosarcoma. We measured and compared the oxygen partial pressure (pO2) profiles in experimental tumors after irradiation with carbon ions and with X-rays. The NFSa fibrosarcomas grown in the hind legs of C3H male mice received isoeffect single doses of carbon ions or X-rays. Coaxial oxygen microelectrodes of high spatial resolution were inserted into the tumor with 20 µm steps by a computerized micromanipulator. The number of pO2 peaks that reached 15 mmHg were
more » ... at least 0.45 per 3,000 µm in unirradiated tumors and significantly increased to 1.55 per 3,000 µm as early as day 1 of carbon-ion irradiation (p < 0.001). The tumors that received X-ray irradiation also significantly increased pO2 peaks, but as late as day 3. The time course of pO2 peak appearance in the present study coincides with a previous report where reoxygenation was measured by paired growth delay assay. The pO2 peaks appeared selectively in peripheral regions of X-ray irradiated tumors, but they appeared rather homogeneously in the tumor after carbon-ion irradiation. It is concluded that carbon-ion irradiation reoxygenated the NFSa fibrosarcomas earlier in time and deeper in space than the Xray irradiation did.
doi:10.1269/jrr.45.303 pmid:15304974 fatcat:naguf3iv3bduhhy67wf7ihtdi4