Previous studies on pulse-height selection for scintillation cameras have been concerned with static imaging or asymmetric window settings around the photo peak. For count densities typical of those encountered in flow studies and for the customary symmetric window it is shown here, both computationally and experimentally, that a window setting in the range of 25-35% provides the maximum lesion detectability rate for lesions of 0.5- to 2.0-cm diameter.

Liver Diseases↗

PubMedDate not supplied

Backscatter factors in the mammographic energy range.

Backscatter factors for kVps and half-value layers typical of mammographic beams have been determined as a function of beam diameter and half-value layer. The method utilized thin TLD-100 chips with the scattering medium alternately present and absent. Results indicate that the field-size dependence of the backscatter factor for lower half-value layers is less than that shown in the British Journal of Radiology Supplement 11.

Mammography↗

PubMedDate not supplied

Mailed thermoluminescent dosimetry reviews in radiation therapy.

The six Centers for Radiological Physics performed periodic thermoluminescent dosimetry (TLD) reviews for photon beams at 276 facilities across the country. The purpose of the reviews and the techniques in use are briefly described. Results from 2413 mailed reviews of megavoltage units indicate that, in 92% of the reviews, a specified dose was delivered within +/- 5% of the TLD-measured dose. A comparison is made to other mailed TLD review systems.

Postal Service↗