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August 1965

Photoscanning in the Diagnosis of Intracranial Lesions

Author Affiliations


From the Department of Internal Medicine, St. Louis University School of Medicine, and the Radioisotope Laboratory, St. Louis Veterans Administration Hospital. Assistant Director (Dr. Donati), Research Chemist (Mrs. Nelson), Chief (Dr. Gallagher), the Radioisotope Laboratory.

Arch Intern Med. 1965;116(2):205-211. doi:10.1001/archinte.1965.03870020045011

IMPROVEMENTS in instrumentation and the utilization of radioactive mercury have made brain scanning available as a clinical diagnostic tool. The basis of differential counting and scanning procedures is a selective increase in the concentration of radioactive materials in brain lesions compared to normal brain tissue.1 Many isotopes and scanning procedures have been previously utilized; however, the development of sensitive detection devices and the use of radioactive mercury has led to increased accuracy of this technique in the localization of intracranial lesions.2-6

203Mercury has biologic and physical properties which make it suitable for photoscanning. The physical half-life is 45 days. When incorporated into a mercurial diuretic, excretion is enhanced and one half of the administered dose is excreted in eight hours.3 Approximately 10% of the labeled diuretic remains bound to the kidneys with a biologic half-life of 28 days. The usual kidney dose of 35 to 40 rads is further reduced