Radiation detecting device for nuclear medicine diagnosis device and detecting method therefor

Abstract

A nuclear medicine diagnosis device which, when a so-called PET collection is carried out, subjects to a coincidence collection not only a gamma ray imparted with a predetermined energy (for example, energy of higher than Compton edge) but also a gamma ray distinguished as one that has generated a photoelectric effect after going through Compton scattering in a radiation detecting unit. Specifically, if an added value of energies observed at two detection elements is in the vicinity of 511 keV, the presence of the above gamma rays is estimated to permit the collection of them. In addition, one element, out of the two detection elements, at which energy near Compton edge is observed can be specified as a gamma ray incident position on a radiation detecting unit.

Description

technical field [0001] The invention relates to a radiation detection device of a nuclear medicine diagnosis device and a detection method thereof. Background technique [0002] Conventionally, it has been provided that drugs labeled with radioactive isotopes (hereinafter sometimes abbreviated as "RI") are injected into the subject, and based on the detection and measurement results of the gamma rays emitted from the RI by the radiation detection means, the A nuclear medicine diagnostic device for graphing the situation of the RI distribution. In particular, a SPECT (Single Photon Emission Computed Tomography) apparatus is widely known as an apparatus or means for capturing the above-described image as a three-dimensional distribution image (tomographic image). Using such an image, the device user or the operator can check the internal conditions of the subject (such as lesion, blood flow, fatty acid metabolism, etc.) without surgical components. [0003] In addition, it r...

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Problems solved by technology

[0009] However, in the case of using the above-mentioned semiconductor detector, its blocking ability is relatively low compared with the above-mentioned scintillator, and most of the incident gamma rays pass through without interacting with the detection element.

Moreover, not only will it pass through without providing any energy to the detection element, but it will also cause Compton to scatter and then pass through or cause Compton to scatter and then cause photoelectric effect

That is to say, in the case of using a semiconductor detector, it is generally difficult to give the energy of all gamma rays to the detection element, so the quality of the image is also affected due to the low collection efficiency of gamma rays

In addition, if the thickness of the semiconductor detection element is increased to solve this inconvenience and improve the blocking ability, Compton scattering will occur many times, and the incident position cannot be determined.

[0010] In addition, even if the above-mentioned scintillation chamber is used, in the case where the scintillator is made of NaI or the like, since its blocking ability is generally low, the same problems as above may still occur.

[0011] Incidentally, such a situation becomes more of a problem at high gamma ray energies

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