1994 Fiscal Year Final Research Report Summary
Development of tumor seeking radiopharmaceuticals for monitoring of photodynamictherapy
| Project/Area Number |
04670660
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Radiation science
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| Research Institution | CHIBA UNIVERSITY |
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Principal Investigator |
UNO Kimiichi Chiba Univ.School of Medicine, Dept.of Radiology, Associate professor, 医学部, 助教授 (30010565)
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| Co-Investigator(Kenkyū-buntansha) |
SAITOH Masayoshi Institute for Training Radiological Technicians.Chiba Univ.School of Medicine, I, 医学部・附属放射線技師学校, 講師
IMAZEKI Keiko Chiba Univ.School of Medicine, Dept.of radiology, Assistant, 医学部, 助手 (50009750)
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| Project Period (FY) |
1992 – 1994
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| Keywords | In-111-tropolone / In-111-TSPC / Tumor Imaging / Photodynamic Therapy / Animal Study |
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| Research Abstract |
The photodynamictherapy (PDT) has attracted considerable interest because it offers the possibility of a selective treatment for cancer For this therapy numerous sensitisers have been studied since 1960s. Clinical trials with one of hematoporphyrin derivatives which is a di-hematoporphirin ester (Photofrin II) were finished in my country. Phthalocyanine as photosensitiser resenbles hematoporphirin and is less toxic for skin than it. We proposed tetra-sulfophthalocyanine (TSPC) as possible tumor affinic carriers for gamma emitting radioisotope. For selection of radioisotopes, we tried to label TSPC with In-111 tropolone and Tc-99m-tropolone. The labeling efficiency and radiochemical purity were assessed by TLC and In-111 was higher labeling efficiency than Tc-99m (95% and 84%, respectively). In-111 has also longer half life. Then we chose In-111-TSPC for studying the distributions in animals which were normal mice, tumor bearing ones, normal rabbits and tumor bearing ones with radioactivity concentration of organ and gamma camera imaging. On our results of animal studies, there was no difference between normal mice and tumor bearing ones. NF sarcoma uptake had the maximum uptake at 24 hours after injection of In-111-TSPC.Images generated at 1,12,24,48 hours after injection were evaluated using normal rabbits and tumor bearing ones. Images at 12-24 hours after injection demonstrate higher resolution. Tumor/mustle ratio of bearing rabbits was 5.56.
Our results demonstrated the feasibility of monitoring TSPC uptake by gamma camera. We optimized the radiolabeling procedure to quantitatively label this agent with In-111-tropolone for the purose of establishing an optimal time window for photoactivation. Further study will be needed to compare to In-111-photofrin-II.
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