Evaluating the potential of (188)Re-ECD/lipiodol as a therapeutic radiopharmaceutical by intratumoral injection for hepatoma treatment.
OBJECTIVE
Intratumoral injection of a radiopharmaceutical is a potential modality to treat liver tumors. Rhenium-188 ((188)Re) was used to chelate with ethyl cysteinate dimer (ECD) in lipiodol solution to form (188)Re-ECD/lipiodol, which was then evaluated for its therapeutic potential in a rodent hepatoma model.


METHODS
Male Sprague-Dawley rats were implanted with N1-S1 hepatoma cells orthotopically and randomly divided into two groups. Group 1 (n = 29) and group 2 (n = 10) received (188)Re-ECD/lipiodol (30.4 +/- 21.8 MBq/0.1 mL) and 0.1 mL of normal saline by intratumoral injection, respectively. Three rats in group 1 were imaged by micro-single-photon emission computed tomography/computed tomography scan to evaluate the biodistribution pattern. All rats were monitored for change of tumor size and survival rate after 2 months.


RESULTS
The in vitro stability test showed that (188)Re-ECD was well-retained in the lipiodol phase for 48 hours. The biodistribution image revealed that radioactivity was retained well in hepatomas 24 hours postinjection. Long-term studies demonstrated that rats treated with (188)Re-ECD/Lipiodol had smaller tumor volumes and a better survival rate, compared to the control group. At the end of observation, the survival rates in groups 1 and 2 were 62% and 20%, respectively (p < 0.05).


CONCLUSIONS
(188)Re-ECD/lipiodol via direct intratumoral injection shows potential for treating hepatoma and warrants further clinical trials.
Luo
Tsai-Yueh
TY
Isotope Application Division, Institute of Nuclear Energy Research, Taoyuan, Taiwan.
Shih
Ying-Hsia
YH
Chen
Chiung-Yu
CY
Tang
I-Chung
IC
Wu
Yu-Long
YL
Kung
Hong-Chang
HC
Lin
Wuu-Jyh
WJ
Lin
Xi-Zhang
XZ
D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D006801:Humans; D015552:Injections, Intralesional / Q000379:methods; D007459:Iodized Oil / Q000627:therapeutic use*; D008113:Liver Neoplasms / Q000532:radiotherapy*; D008297:Male; D009368:Neoplasm Transplantation; D011868:Radioisotopes / Q000627:therapeutic use*; D019275:Radiopharmaceuticals / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012211:Rhenium / Q000627:therapeutic use*; D016896:Treatment Outcome
D011868:Radioisotopes; D019275:Radiopharmaceuticals; D012211:Rhenium; D007459:Iodized Oil