Luceil B. North

Thoracoscopy: Technique and Results in Eighteen Patients with Pleural Effusion

Eighteen patients with pleural effusion were examined. Nine patients had malignant neoplasm and in one the pleura was diffusely involved. Nine patients had pleural effusion of inflammatory origin. One of these was due to tuberculosis, one to trichinosis and the other seven were nonspecific. Thoracotomy in three of these seven failed to add additional information. All patients tolerated pneumothorax well with equilibration of pleural space and atmospheric pressure.

Dosimeter placement in the Rando phantom

Each section of the Alderson Rando phantom contains a tissue-equivalent plastic coating layer approximately 2 mm thick, applied to both faces. This compensates for material removed in the sawing process. Conventional use of thermoluminescent dosimeters positions them totally or partially within the coating layer. Analysis shows that, in the lung region, dosimeters placed in this layer received a dose averaging 39% lower than those placed at midsection. Where bony structures interfere, some dosimeters in the coating layer received an 18% higher dose than those at midsection. Therefore, positioning dosimeters at the center of a section is recommended.

Bone Marrow Dose in Chest Radiography: The Posteroanterior vs. Anteroposterior Projection

The dose to active bone marrow resulting from anteroposterior (AP) and posteroanterior (PA) chest examinations was estimated using an Alderson Rando phantom and extruded lithium fluoride dosimeters. The AP projections resulted in a mean marrow dose range of 1.9-2.6 mrad (0.019-0.026 mGy) as compared to doses for PA projections of 3.4-3.8 mrad (0.034-0.038 mGy) for optimally diagnostic exposure taken at 70, 90, and 120 kVp.

Radiation Lethality in the Opossum

Groups of male opossum (Didelphis virginiana) at 6 months of age were exposed to 350, 500, 550, 600, 650, 700, and 750 rad of whole-body60 Co radiation at a midline dose rate of 125 rad/min. The 30...