X-ray phase contrast imaging (XPCI) is widely regarded as one of the most exciting techniques to have emerged in x-ray physics, and has potential to significantly change the face of biomedical imaging. XPCI, which is based on the refraction of X-rays rather than their absorption, can provide up to 1000 times greater contrast in soft tissues than absorption contrast, which is the current method employed by x-ray equipment. The technique offers enormous potential for earlier diagnosis of diseases and visualization of features currently not visible through conventional techniques, as well as dramatic reduction in dosage to enable safer screening for cancer. Of the several approaches to XPCI, Talbot interferometry is considered to have the most potential for clinical use, as it does not require a synchrotron source. However, the current approach to Talbot phase contrast requires a grating placed near a conventional laboratory X-ray source (the addition of the source grating is called the Talbot-Lau technique). This has led to limits on the X-ray energies used in Talbot-Lau interferometers of less than <20 keV, which has restricted its use (35-80 keV being more optimal for clinical applications), in addition to reduced source efficiency. We propose to develop a high brightness X-ray source that is optimized to enable clinical Talbot interferometers at the higher energies that are relevant to clinical applications. The source employs a novel microstructured anode, which is comprised of an array of tungsten micron-sized X-ray emitters embedded in a material of excellent thermal conductivity and low density (diamond). These micro-emitters act as an array of small sources, which would remove the need for the source grating, and the inclusion of diamond provides superior thermal properties for high brightness. The proposed Phase I 9-month project is a proof-of-principle demonstration that the novel microstructured anode can be manufactured and would provide the desired thermal benefits and x-ray output, and the proposed Phase II 24-month project would produce two working prototypes of the source.
This project proposes to develop a high brightness X-ray source that is optimized to enable clinical x-ray phase contrast imaging (XPCI), which provides up to 1000X more contrast than the current x-ray imaging technique of absorption contrast. Bringing phase contrast capabilities to hospitals and clinics would have a dramatic impact on diagnosis and treatment, as it has the potential to provide accurate diagnosis of the early stages of many soft tissue diseases (which is important for higher survival rates and better treatment plans) and can reduce radiation dosage for much safer cancer screening techniques. Among the many potential applications that have been envisioned for XPCI, osteoarthritis (impacting 1 in 2 Americans) and breast cancer (impacting 1 in 8 American women) are considered as two extremely high potential applications that would benefit from clinical XPCI immensely and in the short term.