Photon counting detectors in medical imaging

by Mats Danielsson (Medical Imaging group, department of physics, KTH)

Thursday 12 Nov 2009, 10:00 → 11:00 Europe/Stockholm

FA32

Mammography and Computed Tomography (CT) are two very common medical imaging procedures with more than one million examinations per year only in Sweden.We will discuss state-of-the-art as well as new developments in terms of photon counting instrumentation. The requirement on spatial resolution as well as contrast resolution is very high, for exampe to detect and diagnose cancer. Because of the large number of patients going through these procedures it also becomes very important to minimize the radiation dose. Photon counting may be one way to meet the demands and mammography is the first modality in x-ray imaging to implement photon counting detectors in clinical practise, currently in routine clinical use in more than 15 countries.

The photon counting enables a discrimination of all electronic noise and a more optimum use of the information in each x-ray. The absence of electronic noise is particularly important in low dose applications. Using the spectral information for each x-ray it is in principle possible to deduce the elemental composition of an object in the breast. This could for example be used to enhance the object of interest, such as a contrast agent relative to soft tissue and bone and improved visualization of vascular structure. For example, a photon counting detector gives a unique opportunity to image Iodine based contrast agents through spectral imaging by adjusting one of the thresholds to its K-edge.