QUASI-MONOCHROMATIC X-RAY SOURCE FOR MAMMOGRAPHY

Description (provided by applicant): The objective of the proposed research is to construct a prototype narrow-bandwidth x-ray source for mammography using a
thin, efficient hybrid radiator driven by a relativistic electron beam of
moderate energy and current. The high x-ray yield (photons/electron) of the
source permits the use of modest electron-beam currents, preventing thermal
damage to the radiator itself. The radiator is thin, permitting the electron
beam to pass through it many times, thereby proportionally increasing the
emitted x-ray flux. Since the source is inherently collimated and
quasi-monochromatic, it will produce higher quality radiographic images while
lowering the dose to the patient. Phase I experiments have demonstrated intense
quasi-monochromatic x-rays in the range optimum for mammography (15 to 25 keV).
Calculations of the x-ray yield and the average current passing through the
radiator have demonstrated that there is adequate flux for imaging. The
research will proceed by improving the design of the thin hybrid radiator and
experimentally demonstrating its feasibility by producing images of inanimate
phantoms. The potential for successful development of the prototype imaging
system is very high because our Phase I research has already experimentally
demonstrated, both electron recycling and narrow bandwidth, tunable x-ray
generation. These results indicate that a high quality mammogram can be
generated in less than 3 seconds.