Evaluation of the calibration parameters of radiochromic films for patient dosimetry in interventional radiology.

The study aims to analyse the effects of beam energy, dose fractionation, response homogeneity, long-term fading and response sensitivity of radiochromic films. It also investigates the effect of the scanner, ambient temperature and storage conditions on the response of the films. The radiochromic films were irradiated at various air kerma from 20 mGy to about 8 Gy. Results showed that the response of the films is not energy dependent for low doses ranging from 300 to 700 mGy (coefficient of variation = 5-12%) but starts to show a slight dependence for high doses above 2 Gy (coefficient of variation = 20%). There is no significant difference (4%) in optical densities (OD) and pixel values when doses were fractionated and when using scanner with and without warm-up lamp. The curve fitting of OD and pixel values for the sensitivity test at different kilovolt potential gave an r(2) value of 0.99.

Nova Scotia Breast Screening Program experience: use of needle core biopsy in the diagnosis of screening-detected abnormalities.

PURPOSE: To evaluate a mammography screening program that uses a multidisciplinary team approach and needle core biopsy. MATERIALS AND METHODS: A total of 10,000 asymptomatic women (aged 40-74 years) underwent screening in the Nova Scotia Breast Screening Program between June 1991 and April 1994. Women aged 50-69 years were the target group. All mammograms were read by one of four radiologists. Patients with abnormal screening findings underwent work-up, which included needle core biopsy, at one of two diagnostic centers. RESULTS: Of 10,000 women, 2,794 were aged 40-49 years; 4,097, 50-59 years; 2,941, 60-69 years; and 168, 70-74 years, with 3.9, 6.4, 12.2, and 23.8 cancers detected per 1,000 patients, respectively. The overall rate was 7.7 cancers detected per 1,000 patients. Abnormalities were detected at screening in 838 patients (8.4%), 181 of whom underwent open surgery, with malignancy diagnosed in 77 (42%). Sixty-one (79%) of 77 patients had stage 0 or I cancer. In 43 (72%) of 60 patients in whom node status was assessed, findings were negative. CONCLUSION: A screening program with needle core biopsy and a multidisciplinary team approach to diagnosis is effective.