A prototype of a quasi-monochromatic system for mammography applications.
Improvement in image contrast and dose reduction, in mammographic x-ray imaging, can be achieved using narrow energy band x-ray beams in the 16-24 keV range. As part of an Italian Government funded project, a quasi-monochromatic system for mammography applications has been developed. The system is based on a tunable narrow energy band x-ray source operating in the 16-24 keV energy range. The bremsstrahlung beam is monochromatized via Bragg diffraction by a highly oriented pyrolytic graphite mosaic crystal (HOPG). The scanning system provides a large field (18 x 24 cm2) of quasi-monochromatic x-rays with energy resolution ranging from 10% at 18 keV to 17.2% at 24 keV. The system has been characterized in terms of fluence rate and energy resolution. An x-ray tube developed ad hoc allows us to acquire images in a reasonable time to minimize the motion blur. A qualitative analysis has been performed in order to know if the prototype system performances are far from a clinical application, by evaluating the spatial resolution, the field uniformity and the image quality as a function of the quasi-monochromatic beam energy. Dose evaluation has been performed as a function of the energy and compared to a conventional system for mammography. The quasi-monochromatic prototype system can produce comparable image quality at half the dose.
Baldelli
P
P
Dipartimento di Fisica, Università di Ferrara, Via Paradiso 12, 44100 Ferrara, Italy. baldelli@fe.infn.it
Taibi
A
A
Tuffanelli
A
A
Gilardoni
M C
MC
Gambaccini
M
M
D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D008327:Mammography / Q000295:instrumentation*; D019047:Phantoms, Imaging; D010865:Pilot Projects; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011874:Radiometry; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012680:Sensitivity and Specificity