Patent ID: 7427761

Claim:
A visualizing apparatus utilizing a gamma ray source, the apparatus comprising: a collimator which is arranged around a measurement object including a gamma ray source, and which permits gamma rays in a specific incoming direction from the gamma ray source to pass through the collimator; a gamma ray detector which performs a relative rotational movement or a relative linear movement together with the collimator with respect to the measurement object including the gamma ray source and which detects the gamma rays passing through the collimator; a gamma ray detection signal processing device which processes a gamma ray detection signal detected by the gamma ray detector to measure energy and counted value of the gamma rays; an energy discrimination processing device which performs discrimination and intensity analysis of radioactive nuclides by performing spectrum analysis of gamma ray energy and gamma ray intensity measured for each unit time or unit position; an imaging calculation processing device which forms images of concentration and space distribution of the gamma ray source in the measurement object for each discriminated radioactive nuclide; and an image display device which performs visual display based on calculation processing results from the imaging calculation processing device, wherein the energy discrimination processing device performs discrimination and intensity analysis of radioactive nuclides by taking into account position and time signals of the rotational movement or the linear movement; and wherein the imaging calculation processing device forms an image as an aggregation of discrete pixels by performing repetitive calculation of pixel values showing the gamma ray intensity, using a formula: λ j n + 1 = λ j n ⁢ ∑ k = 1 K ⁢ ⁢ P k n + 1 · c j , k R k n ∑ k = 1 K ⁢ c j , k wherein: λ j : j-th pixel value =gamma ray intensity; P k : gamma ray energy and intensity data measured by the k-th gamma ray detector; R k : data of gamma rays incident on the k-th detector based on the pixel value λ n j after the n-th repetitive calculation; k: serial number indicating the position of the gamma ray detector (total K in the case of T directions); j: the j-th pixel; n: repeat count; and C jk : probability that gamma rays emitted from the pixel j are detected at the k-th detector position (contribution rate to the pixel).