Objective symmetry detector method for gammaencephalography. IV. Investigation of brain tumours

Sixty-six cases with possible brain tumour were objectively classified as having normal or abnormal 99TcmO4 distribution in the skull recorded by the symmetry detector method for gammaencephalography. The diagnostic accuracy in 37 confirmed tumour cases was about 95 percent. Astrocytomas I-II were seperated from astrocytomas III-IV by the degree of abnormality, and meningiomas were seperated from astrocytomas by diverging time-dependent changes in the pathologic isotope accumulation. The high diagnostic accuracy was obtained in spite of low spatial resolution and simplicity of the method. The careful choice of evaluation parameters and the restriction of their normal variance were necessary and effective in optimizing the method.