C-AD Accelerator Physics Seminar

One of the major uses of radioisotopes is for nuclear molecular imaging using a variety of radiotracers. It is a multidisciplinary science that includes physics, chemistry, biology, computer science, mathematics and medicine with the goal of improving human life. These radiotracers can be used in a PET scanner (or other types of scanners) to generate a three dimensional image of the inside of the human body.

PET scanners are used mainly for brain research and cancer detection. The goal of positron emission tomography (PET) is to generate in-vivo images from patients with a disease or abnormal condition. PET scanners detect the 511 keV annihilation gamma rays that are produced when a positron from a nuclear decay interacts with an electron. The gamma rays are given off at nearly 180° from each other and can be detected as originating along a straight line if they arrive at the detectors within a given time interval known as the coincidence window.

I will describe the development of a very novel PET scanner with very high resolution using CZT solid state detectors. A novel feature of this system design is that the CZT detectors are rotated 90 degrees from their conventional orientation to use the C/A ratio such that the depth direction is oriented tangentially to the circular FOV of the tomograph. Thus the expected ~0.25 ? depth resolution of the detectors can be used to provide ultra-high resolution in the transaxial plane.

The CdZnTe detector PET scanner we developed has a 600 micron FWHM image resolution and an excellent energy resolution of < 2 % FWHM. I will also discuss the development and fabrication of gas phase 11CO2 to 11CO, H11CN, 11CH3I and 11CH3OTf auto synthesis system. These systems are used to generate the radiotracers used with PET. The design and fabrication involve understanding the chemistry, utilizing the physics of flow and transport and engineering a final solution that incorporates these effects.