[Investigation of 99mTc labeled tumor seeking agents--usefulness of 99mTc-isoniazid].
For the development of 99mTc labeled tumor seeking agents, 273 drugs and chemicals were evaluated. Agents labeled by SnCl2-HCl method were injected to rats bearing Yoshida sarcoma. Scintigrams of the rats 2 hours after injection and the excised tumor and organs placed on a plate were taken and evaluated their affinity to the tumor. Isoniazid (INH) was found to be the most useful agent as a result of this screening study. Intensive study on 99mTc-INH was subsequently performed. Another labeling method, FeSO4-H2SO4 method, was evaluated and shown to be superior in both absolute tumor uptake and tumor to muscle ratio. Uptake of 99mTc-INH to Yoshida sarcoma occurred early after injection and maintained its level until later time. On the other hand, radioactivity in the blood and muscle decreased rapidly; that is, tumor to blood and muscle ratio showed rapid increase. Other animal tumor models, mouse bearing Ehrlich tumor or Sarcoma 180, were also used to evaluate the usefulness of 99mTc-INH. The labeled agent showed good localization in these tumors too. In conclusion 99mTc-INH might be a good tumor seeking agent and further clinical trials would be warrant.
Yamada Clinic Isotope Center, Toyama-Pref. Japan.
N
N
Yamada
H
H
Takashima
F
F
Nohara
T
T
Fujinawa
T
T
Matsumura
K
K
Koizumi
K
K
Hisada
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000000981:diagnostic imaging; D007538:Isoniazid / Q000031:analogs & derivatives* / Q000592:standards; D007928:Lethal Dose 50; D008297:Male; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging*; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D051381:Rats; D011919:Rats, Inbred Strains; D012510:Sarcoma 180 / Q000000981:diagnostic imaging; D012517:Sarcoma, Yoshida / Q000000981:diagnostic imaging
D015609:Organotechnetium Compounds; C054975:technetium TC 99m isoniazid; D007538:Isoniazid