Feasibility of using a novel pulsed neutron source for in vivo: prompt gamma analysis

This paper outlines the characteristics of a system which incorporates the convenience and availability of isotope neutron sources with the reduction in detection limit achieved by pulsed accelerator beams. The proposed technique involves the high speed rotation under shielding of one or more 252Cf neutron sources around the circumference of a circle containing an aperture which directs the neutron beam towards the organ of interest. The resulting sequence of collimated neutron pulses are thermalized in the body to induce the emissions of capture gamma rays from a particular element. The emitted radiation is monitored using a detection system which is gated off during the presence of a neutron pulse. Limitations on neutron pulse length and detector count time require the attainment of a threshold rotational speed which depends on the duty cycle of the system. Analysis of the system characteristics indicates that, in comparison with the corresponding continuous irradiation system, a tenfold reduction in patient dose would result in an increase in detection limit of only 40%