A fast non-invasive beam check for mammography x-ray units.

A prototype instrument is presented for the indirect evaluation of the main physical parameters characterizing a mammographic x-ray beam. The instrument consists of an x-ray probe with four filtered solid-state detectors connected to a signal-conditioning electronic circuitry and a high-speed digitizer interfaced to a portable personal computer. The system, governed by an ad hoc developed software, can measure kVp, kV waveform, ripple, HVL, exposure time and exposure in a single shot of the x-ray beam with good accuracy. The system should prove very useful to any quality-control programme for mammography.

[The Dosage and Quality of Imaging program and quality assurance in mammography]. / Il programma DQM e la garanzia della qualità nella mammografia.

The aim of the optimization program for mammography (DQM) in Italy is to achieve the best compromise between image quality and dose to patient. 272 centers agreed to the second phase of the program, from February 1987 to January 1990. Exposure, half-value layer (HVL) and focal spot size were measured according to the same methods employed in the first phase of the DQM program (1985), while image quality was evaluated by means of a new performance phantom. The average exposure was 0.96 R (2.48 x 10(-4) C/kg); in 173 (64.3%) centers exposure was less than 1 R (2.58 x 10(-4) C/kg), and only in 3 centers, where a direct X-ray film was employed, was exposure greater than 5 R (12.9 x 10(-4) C/kg). In every center the average whole-breast dose to a reference organ (5 cm thick, composed of 50% fat + 50% water) was calculated on the basis of entrance exposure, HVL, and focus-skin distance; in 63.2% of the centers doses less than 0.15 cGy were employed. The results allowed dose and image quality to be correlated in order to divide the centers (using a film-screen system) into groups with a different efficiency level: in 101 centers dose and image quality were good, in 64 centers too high a dose was employed, in 66 centers image quality was poor, and in 38 centers dose was too high and image quality was poor. It must be stressed that the DQM program can play its role only if each center carries out its Quality Assurance activity after the methods recommended by the World Health Organization.

Radiation probe for indirect evaluation of the high-voltage waveform of a Mo anode mammography unit.

A radiation probe was designed for indirectly determining the high voltage of a Mo anode mammography unit. The real time processing of the probe outputs yields exposure time, voltage waveform, kVp, and ripple in the range 24-40 kVp useful for screen-film mammography. The probe, connected to a portable computer, will be employed in a survey of radiation dose and image quality in mammography as part of an ongoing program in Italy.

A survey of radiation dose and image quality in mammography: an ongoing program in Italy.

A program for mammography optimization in individual x-ray units, named Dose and Quality in Mammography (DQM), is now underway in Italy. The project has three stages: measurement of the parameters that affect dose and image quality by means of devices that are practical to use (specifically designed for the purpose), analysis of data to evaluate dose and image quality and suggestion of possible improvements to each unit operator. Instruments and methods employed in our survey are described. Our results, like those of the American survey (Je78) Breast Exposure: Nationwide Trends (BENT), show widespread variations of exposure, half value layer (HVL), optical density, dose and resolution. Facilities using the same type of x-ray apparatus (Mo target-Mo filter) and film-screen combinations present very different exposure values, ranging from 1.6 X 10(-4) to 27.6 X 10(-4) C kg-1. The causes of these variations--ascribable to the individual units, radiologist preferences, processing condition, kVp indicator and timer accuracy--are being explored.

[A program devoted to dose and quality in mammography (DQM)]. / Programma finalizzato dose e qualità in mammografia (DQM).

Radiological units present different exposure values, (even by a factor 100), for the same radiological examination unless special programs are performed in order to optimize the examinations and to reduce variations. The program named DQM, mentioned in the Circular n. 62 of the Ministry of Health, is planned for mammographic optimization. The steps of the programme are: a) collection of the working parameters in each unit, b) dose and image quality evaluation, c) communication of the results and suggestion for corrective actions. The practical aspects of the program and the results of measurements in 65 mammographic units are presented and discussed. The importance of the Quality Assurance, performed by radiologists and physicists is underlined.