Imaging brain tumors using a multi-wire gamma camera and Thallium-201

Abstract

Gamma cameras based on multi-wire proportional chambers offer much potential as imaging tools in nuclear medicine. Advantages of these detectors over traditional crystal detectors include superior spatial resolution, higher count rate capabilities, portability and low cost. We have developed a gamma camera based on a multi-wire proportional chamber equipped with a high rate, digital electronic read-out system for imaging applications in nuclear medicine. The complete, highly transportable system has been demonstrated to operate reliably and with predictable accuracy in a hospital environment. The camera demonstrates an intrinsic spatial resolution of 1.27 mm and a maximum count rate capability of 1 million cps. Thallium-201 is a radioisotope with a strong affinity for viable tumor tissue owing to its potassium like characteristics. There is substantial uptake in primary and metastatic cerebral tumors with little uptake in the normal brain. It is ideally suited for imaging with a multi-wire proportional chamber due to its relatively low energy photon emission. The gamma camera has been used to image Thallium-201 labeled brain tumors in patients undergoing treatment in order to detect recurrent or residual tumor. The results and images obtained demonstrate the great potential of the gamma camera in the field of neuro-oncology. We present some design features of the camera and results obtained from measurements carried out to assess its performance characteristics. Clinical images obtained using the camera will also be presented.