The determination of electron density by the dual-energy Compton scatter method.

The intensity of Compton scattered photons is directly proportional to the electron density of a substance; therefore it is possible to detect changes in electron density by this noninvasive method. The source-detector geometry has been varied to study the effects of geometry on the calculated electron density values, using a 90 degrees scattering angle. The dual-energy Compton scatter method provides a determination of electron density in known samples, with an uncertainty of less than 1% for the optimal geometry.

The disposable umbrella catheter: an alternative to the standard balloon enema catheter.

The authors describe the use of a new catheter for barium enema examination that eliminates the hazards of the straight and balloon type catheters.

Wilms' tumor metastatic to the mediastinum.

We report two children with mediastinal metastasis of Wilm's tumor. One case presented with a right hilar mass and the other with a posterior mediastina mass. In each instance, no additional radiologic evidence of metastasis was found.