Fabrication and Evaluation of HgI2 Miniature Probes for in-Vivo Medical Applications

Tiny nuclear detector mercuric iodide probes which fit into a syringe needle of 0.9 mm diameter have been fabricated. Spectroscopic evaluation of the nuclear response shows im roved energy resolution of less than 10% for 57Co and 241Am. The probes show long term stability. One of the still unsolved problems of these probes is the lower energy anisotropic spatial response. Single sources of 137Cs and 125I were placed in a water phantom and counted with the probes. Calibration of the probes against the calculated dose rates for these sources, was carried out, and plotted.