sodium-pertechnetate-tc-99m and Thoracic-Diseases

It has been reported that the inhalation of pertechnegas (TGO3) generated under an atmosphere of 3% oxygen (O2) in argon (Ar) instead of 100% Ar without O2 in the technegas generator, offers a simple but accurate quantification of clearance from the lungs, permitting it to be used in place of 99Tcm-diethylenetriamine pentaacetic acid (DTPA). The disappearance from the lungs of inhaled TGO3 was so similar to that of inhaled pertechnetate aerosol (TcO4) in this study, that there was neither a statistically significant difference in the clearance half-time (t1/2), nor a difference in the lung images between them. Neither TGO3 nor TcO4 inhalation could distinguish smokers from non-smokers using t1/2. When inhaled, TGO3 appears to behave in a similar manner to TcO4 in the lungs and hence cannot be used in place of 99Tcm-DTPA in clinical practice.

Topics: Administration, Inhalation; Adult; Aerosols; Graphite; Humans; Lung; Metabolic Clearance Rate; Middle Aged; Pilot Projects; Radionuclide Imaging; Reference Values; Smoking; Sodium Pertechnetate Tc 99m; Thoracic Diseases

Radionuclide parathyroid scans are widely used to localize abnormal parathyroid glands. They are especially valuable for identifying ectopic glands, including those in the mediastinum. Two patients with hyperparathyroidism who had mediastinal glands that were not identified because only the neck was scanned prompted our review of the technique of parathyroid scanning at hospitals in our region and of the frequency of mediastinal parathyroid glands identified by scanning at our own institution. The nuclear medicine departments at 72 area hospitals were surveyed. Parathyroid scans were performed at 51 of these hospitals but only 13 (25%) routinely scanned the mediastinum and chest. At our institution 480 parathyroid scans were performed during a 9-year period. Twenty-six mediastinal parathyroid glands were identified by routine scanning of both the neck and mediastinum. Most of these glands could be removed through a cervical incision. However, four required formal thoracotomy and two thoracoscopy.. A radionuclide parathyroid scan limited to the neck is an incomplete study. Scans that do not include the thorax will miss mediastinal glands that occurred in 5 per cent of the patients in our series. Despite this, radionuclide parathyroid scanning was limited to the neck in 75 per cent of surveyed hospitals. This practice increases the chance for failed surgical exploration and increases potential patient morbidity.

Topics: Adenoma; Adult; Choristoma; Female; Humans; Hyperparathyroidism; Male; Mediastinal Diseases; Neck; Nuclear Medicine Department, Hospital; Organizational Policy; Parathyroid Glands; Parathyroid Neoplasms; Radionuclide Imaging; Recurrence; Retrospective Studies; Sodium Pertechnetate Tc 99m; Thallium Radioisotopes; Thoracic Diseases; Thoracostomy; Thoracotomy