69. Clinical application of autoactivation PET imaging derived from C-12 ion radiotherapy.

Kyosan Yoshikawa, Takehiro Tomitani, Mitsutaka Kanazawa, Tatsuaki Kanai, Masahiro Endo, Masahiko Koga, Hirotoshi Katoh, Susumu Kandatsu, Hiroshi Yoshioka¹, Junetsu Mizoe, Hirohiko Tsujii, Katsuya Yoshida², Kazutoshi Suzuki, Fumio Shishido³, and Hiroshi Fukuda⁴
(¹Tsukuba Univ.; ²Chiba Univ.; ³Fukushima Medical Univ.; ⁴Tohoku Univ.)

Keywords: HIMAC, C-12 ion radiotherapy, autoactivation, patient fixation system

Clinical application of PET imaging of autoactivation derived from C-12 ion radiotherapy was studied. For investigation of how the tissue metabolism would affect the RI distribution in the tissue, live and dead rabbits were irradiated using C-11 beam. When live rabbit was irradiated, the RI in the irradiated field decreased rapidly than when dead rabbit was irradiated. It calculated that the tissue metabolism reduced the RI activity about 50% less than non-metabolism. This mean that the estimation of the irradiated dose should be strongly concern about the regional metabolism, and this kind of examination should give us the important data to the analysis of clinical autoactivation PET image.

We also studied and designed the patient fixation system for autoactivation PET measuring. It is very important to perform the PET measurement under exactly same positioning of patient as HIMAC therapy. By this, it is possible to compare RI distribution with therapy planning. Now we have finished to design the fixation system, and it is under construction. The system will be available at the end of march in 1999.