Instrumentation for imaging lesions labeled with beta or conversion electron emitters

Part 1. Coronary artery disease is the leading cause of death in the developed world. Vulnerable plaque, believed to cause 70% of all heart attacks, is not identifiable with currently used diagnostic modalities. It is possible to design beta-emitting radioactive tracers that bind to vulnerable plaque sites. The nature of the beta-tracers is that the detection has to be performed in situ. Several miniature, compact, and flexible intravascular beta-imaging probe designs are investigated. The probes are placed by a guidewire during an angiogram session. A six-detector element probe was designed and built. This probe utilizes scintillating fibers coupled to optical fibers, which are in turn coupled to a position-sensitive photomultiplier tube (PSPMT). A linear image of the beta-distribution inside of the artery is presented on the computer screen. The system resolution is 6.7 mm and the sensitivity is 400 cps/muCi when the beta source is 1 mm from the detector. A higher resolution probe is explored with several scintillating fibers coupled in series, with each scintillating fiber emitting a unique wavelength spectrum. The light components are separated before the PSPMT with a diffraction grating. An optical stimulated luminescence imaging device with Al2O 3 is also explored. An imaging probe with silicon detector arrays with 0.5 x 0.5 mm2 pixels was designed and built. The probe utilizes three 20 x 1 pixel arrays coupled in series through a resistive network. Each end of the pixel-chain is read out with preamplifiers, creating a one-dimensional imaging device.;Part 2. The success of surgical procedures for brain tumor patients depends on the extent to which the neurosurgeon is able to remove all of the tumor cells from the patient. Current imaging modalities do not enable the neurosurgeon to adequately visualize the tumor margins. Brain movement during surgery also invalidates any preoperative images. Two small, compact, and high-resolution intraoperative probes for imaging beta-labeled residual cancer cells have been designed and built. These probes utilize: (1) a scintillator crystal coupled through optical fibers to a multi-channel photomultiplier tube, and (2) a silicon 32 x 32 strip detector. Both setups are read out with a resistive network to create a two-dimensional beta-distribution image.