[Tumor imaging using 201Tl chloride and 67Ga citrate in nucleomedical surveys]

Among nucleomedical examinations for cancer, tumor imaging using 201Tl chloride and 67Ga citrate can be easily performed at almost any hospital. However, the planar images usually obtained are not sufficient to detect small tumorous lesions. For more accurate detection, tomographic images particularly single photon emission CT (SPECT) is necessary. SPECT is also indispensable in cancer diagnosis. Whether 201Tl SPECT or 67Ga SPECT is chosen depends upon tumor localization, histological type, and the final purpose of the study. 201Tl accumulates in almost all tumors, but it is not suitable for detection of abdominal lesions, because there is much physiological accumulation in the small intestine and kidney. In contrast, 67Ga does not always accumulate in adenocarcinomas. 201Tl SPECT and 67Ga SPECT are more useful in the functional imaging of cancer than is morphological tumor diagnosis. Both methods are useful in monitoring treatment effectiveness, detecting recurrent lesions after surgery and radiotherapy, and predicting the grade of malignancy of the tumor. Tumor SPECT using 201Tl chloride and/or 67Ga citrate provides clinically useful information not obtained by morphological tumor diagnosis only.