Energy dependence of the response of lithium fluoride TLD rods in high energy electron fields.

The energy dependence of lithium fluoride dosemeters is a complicated function of energy as well as of cavity size. In the application of TLD to charged particle dosimetry, a cavity perturbation effect may exist even though the ratios of the mass stopping powers are constant over the energies encountered. This effect was investigated for lithium fluoride rods in electron fields ranging in energy from 2-5 to 20 MeV. A 13% change of TL response per unit of absorbed dose was measured over that energy range. A semi-empirical theory was developed to account for the cavity effect, using Burlin cavity theory as a starting point. The agreement between theory and measurement is satisfactory.

Breast thermography. A prognostic indicator for breast cancer survival.

A prognostic classification for thermographic staging of breast cancer has been applied to a cohort of 70 patients from 5040 screenees enrolled in the Albert Einstein Medical Center (AEMC) Breast Cancer Detection Demonstration Project (BCDDP). A diagnosis of breast cancer was established in each case before December 31, 1980. None of the patients have been lost to follow-up which extended from a minimum of 6 to a maximum of 13 years. Survival rates for those with favorable, equivocal, and poor thermographic factors are compared with each other and with results in accordance with tumor-node-metastasis (TNM) classification. As of December 31, 1986, there have been 22 (31.4%) deaths, all attributed to breast cancer. The thermographic scoring system clearly shows shorter survival for patients with poor thermographic prognostic factors, 30% surviving at 5 years and only 20% at 10 years compared with overall survival of 80% at 5 years and 70% at 10 years.