IEC 60789-2005 pdf – Medical electrical equipment – Characteristics and test conditions of radionuclide imaging devices – Anger type gamma cameras.
1 Scope This International Standard specifies test methods for declaring the characteristics of Anger type GAMMA CAMERAS . The latter are composed of a collimator, a detector shield and a radiation detector assembly, together with recording and display devices. It is not within the scope of this standard to address the safety requirements to be followed by manufacturers according to IEC 60601-1. 2 Normative references The following referenced documents are for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60788:2004, Medical electrical equipment – Glossary of defined terms 3 Terms and definitions For the purposes of this document, the definitions given in IEC 60788 (see Index of defined terms) and the following apply. 3.1 ENERGY WINDOW range defining the energy signals accepted by the device for further processing 3.2 DETECTOR FIELD OF VIEW FOV region of the detector within which events are included in the display image, and for which all performance specifications are provided 3.3 COLLIMATOR FRONT FACE surface of the COLLIMATOR which is closest to the object being imaged 3.4 COLLIMATOR BACK FACE surface of the COLLIMATOR which is closest to the RADIATION DETECTOR ASSEMBLY 3.5 ENTRANCE FIELD OF A COLLIMATOR area bounded by the shortest line which is tangential to the outside edges of the peripheral COLLIMATOR apertures on the COLLIMATOR FRONT FACE
3.6 EXIT FIELD OF A COLLIMATOR area bounded by the shortest line which is tangential to the outside edges of the peripheral COLLIMATOR apertures on the COLLIMATOR BACK FACE 3.7 COLLIMATOR AXIS straight line which passes through the geometrical centre of the EXIT and ENTRANCE FIELDS of the COLLIMATOR 3.8 PARALLEL HOLE COLLIMATOR COLLIMATOR with a number of apertures, the axes of which are parallel 3.9 PIN – HOLE COLLIMATOR COLLIMATOR with one small aperture in a plane in front of the RADIATION DETECTOR ASSEMBLY 3.10 ADDRESS PILE UP < GAMMA CAMERA > false address calculation of an artificial event which passes the ENERGY WINDOW , but is formed from two or more events by the PILE UP EFFECT 3.11 PILE UP EFFECT false measurement of the pulse amplitude, due to the absorption of two or more gamma rays, reaching the same radiation detector within the RESOLVING TIME [IEC 61675-1, definition 22.214.171.124] 3.12 SYSTEM SENSITIVITY < GAMMA CAMERA > with a specified COLLIMATOR and ENERGY WINDOW , the ratio of the COUNT RATE of the DETECTOR HEAD to the ACTIVITY of a plane source of specific dimensions and containing a specified radionuclide placed perpendicular to and centred on the COLLIMATOR AXIS under specified conditions NOTE See also Figure 2. 3.13 INTRINSIC LINE SPREAD FUNCTION line spread function measured with a collimated line source in front of the DETECTOR HEAD without COLLIMATOR 3.14 DETECTOR HEAD LINE SPREAD FUNCTION line spread function measured with an uncollimated line source at a specified distance Z from the COLLIMATOR FRONT FACE 3.15 EQUIVALENT WIDTH EW width of a rectangle having the same area as the LSF and a height equal to the maximum value of the LSF
3.16 SPATIAL RESOLUTION ability to concentrate the count density distribution in the image of a POINT SOURCE to a point [IEC 61675-1, definition 2.4] 3.17 SYSTEM SPATIAL RESOLUTION < GAMMA CAMERA > SPATIAL RESOLUTION in a scattering medium for a specified COLLIMATOR , or a specified radionuclide, and at a specified distance from the COLLIMATOR FRONT FACE 3.18 INTRINSIC SPATIAL RESOLUTION < GAMMA CAMERA > SPATIAL RESOLUTION in air for a specified radionuclide excluding the COLLIMATOR 3.19 INTRINSIC ENERGY SPECTRUM measured histogram of pulse heights for the DETECTOR HEAD without COLLIMATOR NOTE The pulse height should be expressed as corresponding energy. 3.20 INTRINSIC ENERGY RESOLUTION FULL WIDTH AT HALF MAXIMUM of the full energy absorption peak in the INTRINSIC ENERGY SPECTRUM for a specified radionuclide 3.21 MULTIPLE WINDOW SPATIAL REGISTRATION measured position of a source as a function of the ENERGY WINDOW setting 3.22 INTRINSIC NON – UNIFORMITY OF RESPONSE NON – UNIFORMITY OF RESPONSE of the DETECTOR HEAD without COLLIMATOR 3.23 SYSTEM NON – UNIFORMITY OF RESPONSE NON – UNIFORMITY OF RESPONSE of the DETECTOR HEAD with COLLIMATOR 3.24 SPATIAL NON – LINEARITY deviations of the image of a straight line source from a straight line 3.25 INTRINSIC SPATIAL NON – LINEARITY SPATIAL NON – LINEARITY of the DETECTOR HEAD without COLLIMATOR 3.26 COUNT LOSS difference between measured COUNT RATE and TRUE COUNT RATE , which is caused by the finite RESOLVING TIME of the instrument [IEC 61675-1, definition 2.7.1]