Imaging in Pleural Mesothelioma Diagnosis

Mesothelioma News

Gamma Camera Coincidence Imaging May Aid Pleural Mesothelioma Diagnosis

September 13, 2002 — Researchers recently studied the use of gamma camera coincidence imaging in pleural mesothelioma diagnosis (J. Nucl Med 2002 Sept; 43(9): 1144–1149). Patients were given the radioactive tracer compound (18)F–FDG (fluorodeoxyglucose) to measure the extent of cancer cells. The substance collects in cancerous areas, giving off gamma rays. The gamma camera records the distribution of the chemical. “Coincidence imaging” makes use of different detectors in opposing directions, recording an overall picture of the diseased areas.

Fifteen patients had irregular thickening of the pleura (the thin covering that protects and cushions the lungs) or pleural calcifications (mineral deposits), according to standard computed tomography or CT scans. These patients were given injections of (18)F–FDG, then subjected to gamma camera coincidence imaging 1.5 hours later. The results of the gamma coincidence imaging were compared to data obtained from routine microscopic examination of tissue.

According to the microscopic analysis, 11 of the 15 patients had pleural mesothelioma. The gamma coincidence imaging detected primary tumors in all 11 cases; and confirmed that the other four patients did not have the disease. Twenty–nine out of 34 lesions were positive for tumors. The gamma coincidence imaging detected 28 of these. Overall sensitivity, specificity, and accuracy of detection using gamma coincidence imaging was 97%, 80%, and 94%, respectively, compared with 83%, 80%, and 82% for CT scans. The researchers concluded that these preliminary results showed that gamma camera coincidence imaging may be an accurate method to diagnose the extent of disease in patients with pleural mesothelioma.