Process and apparatus for scanning sections of radiation

Abstract

The process of this invention includes detecting gamma radiation with a radiation sensing device, converting the gamma radiation to light radiation, viewing the light radiation with photomultiplier tubes and giving electrical impulses in response thereto. The impulses are operated on to correct for any distortion and to give an indication of the relation to location of the radiation. An area of interest, for the purpose of scanning, is selected and electronically masked. During a first pass, initial scanning is done electronically without physical movement of the radiation sensing device head. After initial electronic scanning, a detector head passes over the radiation of interest while sensing radiation. At the end of the mechanical movement, an area of radiation is again electronically scanned. A cot supporting the section of radiation is moved transverse to the longitudinal movement of the head after the first pass. A scan in the opposite direction occurs similar to that in the first direction. The radiation is correlated between the first scan and the second scan. In order to reduce artifacts, the perimeters of the areas under consideration are oscillated with a saw-tooth wave. The apparatus includes a radiation sensing device for scanning a section of radiation, normally an irradiated patient. The radiation sensing device includes a camera detection head and has a collimator which channels radiation, normally gamma radiation, from the patient to a scintillation crystal operatively attached thereto. The scintillation crystal converts gamma radiation to light radiation which is noted by photomultiplier tubes viewing the scintillation crystal. Electrical responses given by the photomultiplier tubes are operatively attached to means for operating on the electrical impulses to create a signal which gives an indication of the relative location of the radiation. A drive means moves the camera head in a longitudinal direction along a cot supporting the patient. At each end of the mechanical movement of the head, an electronic scanner views the ends of the section of radiation under consideration. Appropriate mechanical drive means moves or indexes the table supporting the patient in a direction transverse to the longitudinal movement of the detector head. A means for blending the radiation received from multiple passes of the detector head includes an electronic mask with oscillating sides. In this manner, multiple passes can be blended without substantial artifacts. A means for sequencing events governs the proper order of events.