IEC 63073-1-2020 pdf download.Dedicated radionuclide imaging devices – Characteristics and test conditions – Part 1: Cardiac SPECT.
Unless otherwise specified, SPECT characterization shall be provided for an acquisition covering the minimal rotation required to obtain a complete set of data (e.g. 1 20° for a three- headed rotating-gantry system). If a rotating-gantry tomograph is specified to operate in a non- circular orbiting mode influencing the performance parameters, test results for the non-circular orbiting mode shall be reported in addition. Unless otherwise specified, measurements are carried out at COUNT RATES not exceeding 40 000 counts per second on each CARDIAC DETECTOR HEAD and not exceeding 1 20 000 counts per second for the system.
4.2 Detector characteristics
4.2.1 General Evaluation of detector characteristics for cardiac systems are performed extrinsically (with COLLIMATORS in place). Additionally, for systems that allow the removal of the COLLIMATOR , intrinsic detector characteristics shall be specified and tested in accordance with IEC 61 675-2.
4.2.2 Energy resolution and LOW – ENERGY – TAIL RATIO measurement
4.2.2.1 General Energy resolution describes the ability of the detector to properly identify the energy of the detected photons. Due to incomplete charge collection, the detector material in some cardiac systems may have an increased fraction of photons detected with reduced energy. The effect is characterized by measuring the LOW – ENERGY – TAIL RATIO . An energy spectrum is determined for each CARDIAC DETECTOR HEAD .
4.2.2.2 Purpose The energy resolution is measured to characterize the ability of a GAMMA CAMERA to separate photons with different energies.
4.2.2.3 Method Measure an energy spectrum in low scatter configuration using an irradiation of the entire CARDIAC DETECTOR HEAD . This measurement is performed separately for each CARDIAC DETECTOR HEAD .
4.2.2.4 R ADIONUCLIDE The sources are 99m Tc and 57 Co.
4.2.2.5 R ADIOACTIVE SOURCE DISTRIBUTION A LINE SOURCE with internal diameter of < 1 ,2 mm is placed so as to illuminate the entire CARDIAC DETECTOR HEAD . The COUNT RATE shall not exceed 40 000 counts per second.
4.2.2.6 Data collection For each CARDIAC DETECTOR HEAD , the pulse height spectrum is obtained with a channel width less than or equal to 5 % of the expected photopeak FWHM. The number of counts in the peak channel is greater than 1 0 000. The spectrum is obtained over the entire usable energy range of the detector.
4.2.2.7 Data processing
For the energy spectrum, the channel numbers are expressed in terms of energy by scaling the channel number by the difference in peak energies of the two RADIONUCLIDES divided by the difference in their measured peak channel positions.
4.2.2.8 Data analysis
For each CARDIAC DETECTOR HEAD , the energy resolution, E FWHM , is the FWHM of the full energy absorption peak with a peak energy, E peak , closest to the expected photopeak energy.IEC 63073-1 pdf download.