Extraosseous accumulation of 99mTc phosphonate complexes in primary brain tumor evaluated with SPECT

Although extraosseous accumulations of 99mTc phosphate complexes are phenomena which can often be seen, no case showing extraosseous accumulation to brain tumor on SPECT has been reported. We report here two cases of primary brain tumor showing extraosseous accumulation of 99mTc phosphate in bone SPECT. 201Tl SPECT also showed increased 201Tl uptake by the tumor. Comparing bone SPECT with 201Tl SPECT, the regions of abnormality of both SPECTs were very similar in the case of glioblastoma, but in the case of malignant lymphoma the region showing intense uptake of 99mTc-MDP was smaller than that on 201Tl SPECT. It was revealed that bone SPECT is more useful in the assessment of extraosseous accumulation to a primary brain tumor than conventional bone scintigraphy.