[Measurement of hematocrit of brain tumor using SPECT]

The cerebral-to-large vessel hematocrit ratio (alpha) was measured using single-photon emission computed tomography (SPECT) in patients with brain tumors. SPECT was performed following intravenous injection of 99mTc-labelled red blood cell and 99mTc-labelled human serum albumin with an interval of 72 hr. In a series of seven subjects, the mean value of "alpha" in tumor (0.74 +/- 0.13) was lower than that (0.83 +/- 0.14) in normal brain tissue. This result may be due to the increased flow of red blood cells in tumor.