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Fig. 9 | EJNMMI Physics

Fig. 9

From: Comprehensive SPECT/CT system characterization and calibration for 177Lu quantitative SPECT (QSPECT) with dead-time correction

Fig. 9

Observed photopeak (a, 187–226 keV) and wide-spectrum (b, 18–680 keV) count rates vs. XW. The term XW is the product of activity and observed acquisition count rate (photopeak or wide-spectrum), divided by the observed primary photon count rate (Eq. 3). Coloured horizontal dotted lines indicate the maximum usable observed photopeak count rates, which is geometry-dependant (a; that of the CTDI-16 phantom could not be precisely determined due to missing points at high activity). The black horizontal dotted line corresponds to the unique, geometry-independent maximum wide-spectrum count rate (b). Planar data (Air-2D, averaged for both detectors) is shown for comparison

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