Tl-201 SPECT for assessing tumor viability in recurrent malignant neoplasma of the brain and soft tissues

This paper evaluates the usefulness of Tl-201 SPECT imaging in the detection of viable tumor vs necrosis and/or inflammation in brain and soft tissue tumors. Tl-201 SPECT, F-18-FDG PET, and CT with contrast medium were done 6 weeks prior to biopsy confirmation in 11 patients with suspected recurrent tumor (nine brain and two soft-tissue tumors). Tumor-nontumor ratios were obtained on attenuation-corrected transaxial images. The CT scans were reviewed prior to reading the SPECT and FDG PET scans. Seven of 11 patients had recurrent tumors (five brain and two soft tissue) on biopsy and all were positive on SPECT (mean ratio, 4.0 ± 0.8) and hypermetabolic on FDG PET scans. Two of seven had equivocal findings on CT