RT Journal Article
SR Electronic
T1 Prediction of therapeutic effect of tumor photo dynamic therapy
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1613
OP 1613
VO 50
IS supplement 2
A1 Yasuhiro Magata
A1 Le Biao
A1 Hiroshi Yamaguchi
A1 Takeshi Fuchigami
A1 Harumi Sakahara
YR 2009
UL http://jnm.snmjournals.org/content/50/supplement_2/1613.abstract
AB 1613 Objectives Usefulness of Tc-99m-MIBI for prediction of therapeutic effect of tumor photo dynamic therapy (PDT) was studied by in vitro experiments. It is reported that apoptosis of tumor cells is induced by PDT using photophrin which is widely used as a PDT drug, and mitochondria functional disorder induces apoptosis. It is expected that Tc-99m-MIBI can be used for evaluation of mitochondria functional alteration by photophrin-PDT therapy since it is reported that retention of radioactivity post-injection of Tc-99m-MIBI in tumor cells depends on mitochondria membrane potential. Methods Tumor cells SCC7 or Hela, 1x105 dish were cultured in 35 mm dishes for 24 hours before experiments. After exposure of the tumor cells with photophrin (10 uM) for 3hrs, laser irradiation (10J/cm2) on each dish was carried out. A mixture of 40kBq of Tc-99m-MIBI and 40kBq of F-18-FDG was added in each dish at 0, 1, 3 and 6 hr post-irradiation. Then, uptake of radioactivity and viable cell number were evaluated after more 10 min incubation and twice washing medium. Results Viable cell number decreased up to around 40% compared with control study. At 3hr post-irradiation, the remaining F-18 and Tc-99m radioactivity in each dish decreased up to 40% and 30%, respectively. On the other hand, only Tc-99m radioactivity remained for viable cells decreased up to 30% compared with before irradiation. Moreover, similar results were observed by addition of apoptosis inducing agent, staurosporin instead of PDT treatment. Conclusions These results suggest that in vivo FDG uptake post photophrin-PDT shows viable cell number and alteration of Tc-99m-MIBI uptake indicates mitochondria functional disorder in addition. Verification studies in in vivo experiments are now underway.