ADVANCED IMAGING STRATEGIES FOR PREVENTION AND EARLY DETECTION
Orhan Nalcioglu, PhD, FIEEE, FAAPM, FISMRM
Professor & Director
Tu & Yuen Center for Functional Onco-Imaging
University of California
Irvine, CA 92697
Medical imaging could be used to perform non-invasive and spatially resolved anatomic and metabolic measurements in living systems. Performance of anatomical measurements is a lot easier than the metabolic ones since the later is strongly limited by measurement sensitivity. The early applications of any imaging technique is usually focused towards diagnosis of a disease such as cancer but may later evolve towards early diagnosis or screening if it has adequate sensitivity and specificity. Obviously the next step in this type of evolution is to use imaging in cancer prevention monitoring when successful cancer prevention strategies are introduced.
Computed tomography systems introduced during the early 1970s have enhanced the impact of imaging in medicine greatly. After the introduction of x-ray computed tomography (XCT), other tomographic imaging techniques such as PET, SPECT, and MRI followed and have become part of the arsenal of imaging tools used clinically and in research. During the past few decades there has been significant developments in the application of optical imaging techniques as well. These include diffuse optical tomography (DOT), fluorescence tomography (FT), optical coherence tomography (OCT), and bioluminescence imaging or tomography (BLI/BLT). Some of techniques are now becoming mature enough to be translated into clinical practice. There are also other novel imaging techniques such as electrical impedance tomography (EIT) that is based on the differences in electrical conductivity of normal and diseased tissues.
Although the general notion earlier was that single modality imaging techniques were competing modalities this has changed greatly with the development of PET-CT technology during the last decade after realizing that acquisition of spatially co-registered complementary information was more than just the sum of its individual components. In the case of PET-CT, unlike the previous approaches using software based image fusion techniques, such a system offers the possibility of more accurate image co-registration and hence improved diagnosis for the first time. In addition to the advantage of co-registration of information from two different imaging devices, multi-modality systems also offer another unique advantage. This is due to the fact that in multi-modality systems one of the devices usually provides higher resolution images than the other. For example, in the case of PET-CT systems, CT offers high-resolution anatomic information whereas PET provides lower resolution metabolic images. Then the question arises whether the information from the high-resolution system could be used to improve the image resolution or quantification in the lower resolution modality.
In this presentation we will discuss several multi-modality imaging technologies that are either being commercialized or under development at several academic institutions. These will include several MR based dual imaging modalities such as MR- PET, MR- SPECT, MR- DOT, MR- EIT, and MR- FT as well as other combinations such as CT- FT.
Citation Information: Cancer Prev Res 2008;1(7 Suppl):ED08-03.
Seventh AACR International Conference on Frontiers in Cancer Prevention Research-- Nov 16-19, 2008; Washington, DC