GRAPHIC RECORDING APPARATUS AND METHOD

摘要

The disclosure describes apparatus for preventing scalloping the photographic film image produced by a scintillation scanner. The described scanner comprises a detector which can be scanned along parallel paths over an area of interest in a patient. The detector is directly coupled to a light-emitting tube that simultaneously is scanned in a similar manner over a photographic film. Gamma rays emitted by the patient are received by the detector and are converted into corresponding electrical event pulses and bits of event information which are sequentially shifted through shift registers in response to periodic clock pulses. A stepping motor moves the detector and light-producing tube a predetermined distance in response to the receipt of each clock pulse so that the concentration of gamma ray events occuring along any particular segment of the detector scan path can be precisely determined. An individual event pulse is transmitted to the light-producing tube after is has been shifted halfway through the shift register, so that the information stored in the shift register represents gamma ray events occurring before and after the gamma ray event resulting in the event pulse. A counter continuously analyzes the information flowing into and out of the shift register so that an accurate count of the information bits stored in the shift register is continuously available. Additional means are provided for controlling the intensity of the light produced by the tube in response to the value of the information stored in the shift register. As a result, the light intensity produced in response to any single gamma ray event depends on the concentration of gamma ray events occurring on either side of the single event along the detector scan path.