EN IEC 63073-1 pdf free download
EN IEC 63073-1 pdf free download.Dedicated radionuclide imaging devices – Characteristics and test conditions – Part 1: Cardiac SPECT.
4.2.6 Non-uniformity for each CARDIAC DETECTOR HEAD
NON-UNIFORMITY OF RESPONSE is assessed for each CARDIAC DETECTOR HEAD according to manufacturer specified procedures. The manufacturer specified procedure is described and the values determined by the procedure are reported.
4.2.7 SCATTER FRACTION
4.2.7.1 General
The scattering of primary gamma rays results in events with false information for radiation source localization. Variations in design and implementation cause emission tomographs to have different sensitivities to scattered radiation. The purpose of this procedure is to measure the relative SYSTEM SENSITIVITY to scattered radiation, expressed by the SCATTER FRACTION (SF).
It is recognized that access to PROJECTION data is not available on all systems. If PROJECTION data are unavailable, the SCATTER FRACTION should be estimated according to the man ufacturerspecified protocol and the exact protocol used is reported along with the SCATTER FRACTION.
4.2.7.2 Purpose
Unscattered events are assumed to lie within a 2 x FWHM wide strip centred on the image of the LINE SOURCE. This region width is chosen because the scatter value is insensitive to the exact width of the region, and a negligible number of unscattered events lie more than one FWHM from the line image.
4.2.7.3 RADIONUCLIDE
The RADIONUCLIDE used for this measurement is 99mTc and the ENERGY WINDOW is 140 keV±10%.
4.2.7.4 RADIOACTIVE SOURCE distribution
A cylindrical phantom (Figure 2) with a LINE SOURCE insert is used. The phantom is filled with non-radioactive water as a scatter medium. The LINE SOURCE of at least 7 cm in length is inserted and positioned on the central axis of the cylinder. The LINE SOURCE is centred on the REFERENCE POINT of the system and aligned with the patient inferior-superior axis.
4.2.7.5 Data collection
The measurement is performed by imaging the LINE SOURCE within a water-filled test phantom using a standard clinical protocol for cardiac tomographic imaging. A total of 10 million counts are acquired in the PROJECTION data.
4.3 Characteristics of tomographic images
4.3.1 CENTRE OF ROTATION (COR)
Measurement of COR is critical to tomographic performance of cardiac cameras with rotating gantries. For cameras with rotating gantries, the COR shall be specified and tested in accordance with IEC 61 675-2.
4.3.2 REFERENCE POINT localization in the reconstructed FOV
4.3.2.1 General
The REFERENCE POINT defines a reproducible spatial location within the FOV of the system.
NOTE Accurate knowledge of the REFERENCE POINT location in the reconstructed image space is crucial for reproducible measurement of system performance.
4.3.2.2 Purpose
To measure the precision of positioning a POINT SOURCE at the REFERENCE POINT.
4.3.2.3 Method
A POINT SOURCE is placed in the camera FOV and the manufacturer specified procedure is used to position the POINT SOURCE at the REFERENCE POINT. The position of the POINT SOURCE in the reconstructed image volume is measured. The procedure is repeated 10 times. Prior to each repetition, the POINT SOURCE is removed and replaced in the FOV, and the camera is reset to its starting position.
4.3.3 Accuracy of tomographic system sensitivity modelling
4.3.3.1 General
Image reconstruction requires knowledge of the system geometry. The system geometry of dedicated cardiac cameras may be complex. Inconsistencies between the assumed and actual system geometry can lead to artefacts affecting the uniformity of reconstructed images.
4.3.3.2 Purpose
The accuracy of tomographic system sensitivity modelling measurements provide information about the consistency, over the FOV of the camera, of the counts in the reconstructed image of a small source.EN IEC 63073-1 pdf donwload.
