Spect ct discovery nm ct 670 system

The Dosimetry Toolkit®, an application of the Xeleris® software provided with the SPECT/CT Discovery NM/CT 670 system (GE Healthcare) [19 ], was used to determine the radiopharmaceutical residence time in segmented organs with the multi-SPECT/CT scenario, as described by Kupitz et al. [20 (link)]. First, the application “Preparation for dosimetry toolkit” was used for SPECT/CT raw data reconstruction and CT data registration. Then, the “Dosimetry Toolkit” application was used to segment the different organs, to create the time activity curves fitted by a mono-exponential function, and to calculate the residence time.
The OLINDA/EXM® V1.0 software [21 (link)] was used to calculate the organ absorbed and effective doses. It contains a large pre-established database of radionuclides and S factors to calculate the absorbed dose per unit of administered activity. Standard or patient-adapted organ masses can be used with this software. The residence times obtained for each organ with Dosimetry Toolkit® were used as input data.

PET/CT images were performed on a time-of-flight PET/CT digital scanner (Discovery MI, GE Healthcare, Waukesha, WI, USA) with a 25 cm axial field of view. A low-dose CT scan (120 kV; automated current modulation; 0.98 pitch; 3.75 mm slice thickness; 0.5-s rotation time) from the vertex of the skull to the mid-thighs was used for anatomic localization and attenuation correction. PET scanning followed at 2 min/bed position with a 27-slice overlap. Images were reconstructed using ordered-subset expectation maximization (OSEM, four iterations, eight subsets, cutoff 6 mm, 256 × 256 matrix) applying all appropriate corrections for dead time, randoms, scatter, coincidence, and detector normalization.
Post therapy images were acquired on a SPECT/CT Discovery NM/CT 670 system (GE Healthcare) equipped with MEGP (medium energy general purpose) collimators and 3/8′′ NaI(Tl) crystal thickness. A 20% energy window centered on the 208 keV photopeak and a 10% scatter correction window centered on 178 keV were applied. Whole-body images were acquired in continuous mode (15 cm/min), with a 1.0 zoom, 2.21 mm pixel size, and an automatic body contour.