In vivo comparison of PET and SPECT radiopharmaceuticals in detecting breast cancer.
Various radiopharmaceuticals for breast cancer detection have been used for scintimammography and PET. However, few comparative studies have described the uptake of radiopharmaceuticals as a method of detecting breast cancer. The aim of this study was to assess the radiopharmaceuticals for breast cancer imaging in experimental mice implanted with breast cancer cells.


METHODS
Six radiopharmaceuticals were studied: three for PET [18F-fluorodeoxyglucose (FDG), L-18F-alpha-methyltyrosine (FMT) and 11C-methionine (C-Met)] and three for scintimammography [99mTc-tetrofosmin (TF), 99mTc-sestamibi (MIBI) and 201Tl-chloride (Tl)]. Biodistributions of six different tracers in mice implanted with MCF-7 breast cancer cells were studied 1 and 3 hr after injection.


RESULTS
Tumor uptake 1 hr after injection was FMT = C-Met > FDG = TF > MIBI = Tl. Thallium-201-chloride showed the highest tumor-to-blood ratio (T/B) among all radiopharmaceuticals because of its fast clearance from circulation. The T/B of the six radionuclides used in this study ranged from 1.26 for C-Met to 12.83 for Tl. Tumor-to-muscle ratio (T/M) revealed FMT = C-Met > FDG > MIBI > TF = Tl. The T/M ranged from 0.20 for TF to 2.29 for FMT. Tumor-to-lung ratio (T/L) varied from 0.45 for TF to 2.41 for FMT. FMT revealed the highest T/L of all six radiopharmaceuticals.


CONCLUSIONS
Among radiopharmaceuticals for PET, FMT seemed to be suitable in detecting MCF-7 tumor; whereas for scintimammography, MIBI, TF and Tl appeared to have almost the same detectability of MCF-7 tumor. The results of this study strongly suggest that FMT may have a potential in breast cancer imaging.
Department of Diagnostic Radiology and Nuclear Medicine, Gunma University School of Medicine, Maebashi, Japan.
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Amano
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Inoue
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Tomiyoshi
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Ando
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Endo
D000818:Animals; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed; D015899:Tomography, Emission-Computed, Single-Photon; D019805:alpha-Methyltyrosine / Q000493:pharmacokinetics
D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D019805:alpha-Methyltyrosine