IN-VIVO RESONANT-GAMMA DETECTION/IMAGING OF N AND CA

RESONANT GAMMA ABSORPTION WILL BE USED FOR IN-VIVO DETECTION AND IMAGING OF BODY NITROGEN AND CALCIUM. TWO MAJOR APPLICATIONS ARE NUTRITIONAL ASSESSMENT OF CRITICALLY ILL PATIENTS AND OSTEOPOROSIS SCREENING. REQUIRED RADIATION DOSES FOR WHOLE- BODY MEASUREMENTS ARE 3-4 ORDERS OF MAGNITUDE LOWER THAN MAY BE DONE BY PRESENT TECHNIQUES. A NOVEL, COMPACT ELECTROSTATIC PROTON ACCELERATOR WILL PRODUCE A 1 MA PROTON BEAM OF ENERGY 1.75 MEV (FOR NITROGEN DETECTION) OR 2.04 MEV (FOR CA DETECTION). PROTONS CAPTURED IN A TARGET PRODUCE GAMMA RAYS RESONANT WITH EITHER N OR CA. THE MEASURED TRANSMISSION OF THE RESONANT GAMMAS THROUGH THE BODY IS USED TO DETERMINE THE BODY CONTENT OF THESE ELEMENTS. THE TECHNIQUE REQUIRES NO RADIOACTIVE SOURCE AND A DOSE SO MODEST THAT BODY SCANS WITH 2 CM RESOLUTION ARE ENVISIONED. PHASE I IS A THEORETICAL EFFORT TO QUANTIFY THE TECHNIQUE, DESIGN AN ELECTROSTATIC ACCELERATOR, AND OPTIMIZE THE GEOMETRIC INTERFACING BETWEEN THE ACCELERATOR, TARGET AND DETECTOR SYSTEM.