Objective symmetry detector method for gammaencephalography. III. Diagnosis of abnormal 99TcmO4 distribution in the skull

Clinical experience with the objective symmetry detector method for gammaencephalography

The objective symmetry detector method for gammaencephalography previously described has been further developed. A rapid micro-computerized automatic measuring device has been constructed and the method used in screening of neurologic patients. The previously chosen classification boundaries between normal and pathologic isotope distributions were not entirely satisfactory for clinical screening of patients with neurologic symptoms. By use of new classification boundaries, 87 per cent of patients with brain tumours could be separated from patients with neurologic symptoms but without gross brain lesions and from neurologically healthy subjects.

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.