Auditing mammographic dose and image quality in the UK breast screening programme

摘要

A national audit of image quality and dose has been conducted across 267 mammography X rya sets in the UK Breast Screening Programme, repeating a previous survey in 1991. The main parameters were film density, film contrast, mean Glandular dose to the standard breast (MGD) and image quality (IQ) measured with a TOR(MAM) test object. Film density has Increased from a mean of 1.33 in 1991 to a mean of 1.61 in 1996 as a result of national guidelines. Over the same period the Average MGD has increased form 1.28 to 1.36 mGy. Average film gradient ranged form 2.2 to 3.9 with a mean of 3.2. IQ ranged From 48 to 86 with a mean of 69. Causes of reduced IQ were low film densities, medium screens and older designs of mammo- Graphy X ray set. Although film density and MGD were generally satisfactory, there apears to be room for further optimisation Of film contrast and IQ.