Patent ID: 6993376

Claim:
A displacement difference dosimetry method for in-vivo measuring of dose rates within a radiation field, the method comprising the steps of: a) providing a scintillating fiber having an insertion end and a coupling end; b) coupling the coupling end of the scintillating fiber to a light intensity measuring device, the light intensity measuring device being located substantially outside of the radiation field and producing a voltage output in accordance with a measured light intensity from the scintillating fiber; c) providing a guide channel having an insertion end and an external end; d) inserting the insertion end of the guide channel into a human body to a region where radiation is to be measured, so as to provide a substantially fixed path into the human body; e) inserting the insertion end of the scintillating fiber into the external end of the guide channel and into the human body along the substantially fixed path; f) subjecting the region of the body at the insertion end of the scintillating fiber to radiation; g) detecting the position Λ of the insertion end of the scintillating fiber along the substantially fixed path within the human body and measuring the light intensity at the light intensity measuring device, with the measured light intensity representing both scintillation light from the scintillating fiber and also Cerenkov light; h) incrementally displacing the insertion end of the scintillating fiber by a small distance ΔΛ to a new detected position Λ+ΔΛ along the substantially fixed path and measuring the light intensity at the light intensity measuring device, with the measured light intensity representing both scintillation light from the scintillating fiber and also Cerenkov light; i) determining a radiation dose rate, substantially free from the effects of Cerenkov light, for an incremental segment from Λ to Λ+ΔΛ along the substantially fixed path according to the expression: Dose Rate= C×ΔV/ΔΛ, where C is a coefficient, ΔV is the change in voltage output of the light intensity measuring device which results from the insertion end of the scintillating fiber being moved between the positions Λ and Λ+ΔΛ, and ΔΛ is the amount of incremental displacement.