Development of miniaturized solid state detectors for the measurement of beta and gamma radiation in superficial and deep parts of living tissue

Abstract The construction of two types of miniaturized probes for in-vivo measurement of beta and gamma radiation is described. The probes use cylindrical lithium compensated silicon detectors as sensing elements. The first type is intended for relatively superficial measurements. It consists of a stainless steel tube 50–100 mm long attached to a cylindrical holder. The steel tube contains one or several detectors, fixed or movable inside the tube. Depending on the size of the sensing elements the outer diameter of the steel tube can be chosen in the interval 1.1 to 4.5 mm. Tube wall thickness is normally 50 μm but can be reduced to 15 μm if required (measurements of low-energetic beta radiation). The second type makes it possible to measure deep inside living tissue. It consists of a detector element similar to those described above but contained in a steel tube 13 mm long and attached to a 50–100 cm long, easily flexible coaxial cable. The outer diameter of the structure is of the order of 1.2–1.5 mm.