Symbia t16 spect ct scanner

For the purpose of scintigraphy, 550 MBq of ^99mTc-PYP was administered intravenously. Imaging was performed on a Siemens Symbia T16 SPECT/CT scanner with low-energy high-resolution collimators with a 15% window centered on the 140 keV photo peak of ^99mTc. All acute patients had a whole-body scan 10 min p.i. as described in previous protocols [24 (link)]. All patients and controls underwent SPECT/CT of the thorax (arms along the body except in one case), and all but one acute patient had SPECT/CT of the pelvis and thighs 3 h p.i. SPECT parameters were 64 projections, 128 × 128 matrix, 40 s/frame at the upper body, and 20 s/frame at the lower body; the lower body scan was accomplished as a two-bed acquisition. CT was performed as a low-dose non-contrast-enhanced scan (130 kV, 20 mAs). SPECT data were reconstructed iteratively (four iterations, four subsets) with scatter and attenuation correction as well as resolution recovery and postfiltered with an 8-mm Gaussian filter. Three-dimensional models (maximum intensity projections) were interpreted visually and transaxial slices quantitatively. Since the investigators themselves collected data, they were not blinded at the time of scintigraphy, but data processing was performed later without looking at the clinical data. Unfortunately, the postponement of the processing resulted in a loss of data for some of the participants.

Planar scintigraphic images were acquired in dynamic mode (128 × 128 matrix; 60 frames of 30 s) in anterior–posterior projection, followed by a static mode (256 × 256 matrix; 4 m) in anterior–posterior and lateral projections (30 m and 2 h post-injection). Dynamic and static scintigraphic imaging was supplemented with 30 s flood field images. SPECT/CT was acquired on a 128 × 128 matrix (pixel spacing, 4.8 × 4.8 mm), with 128 angles, 20 s per projection, over a non-circular 360° orbit (CT: 110 kV, 40 mAs eff., slice thickness 1.2 mm). Both scintigraphic and SPECT/CT images were acquired using a Siemens Symbia T16 SPECT/CT scanner with “low- and medium energy” (LME) collimators to limit septal penetration and reduce shine-through [23 (link)]. SPECT/CT images were reconstructed using clinical reconstruction software (Siemens Flash3D, Siemens Healthineers, Erlangen, Germany), with attenuation and scatter correction (6 iterations, 8 subsets, and a 5mm Gaussian filter).

Lymphoscintigraphy including SPECT/CT acquisition were conducted according to EANM guidelines [11 (link)]. Following peritumoral injections of a ^99mTc-labeled radiotracer (i.e., ^99mTc-nanocolloid or ^99mTc-tilmanocept) planar static and dynamic scintigraphy as well as SPECT/CT were acquired the day prior to surgery (2-day protocol) or the day of surgery (single-day protocol) on a Siemens Symbia T16 SPECT/CT scanner; equipped with low-medium energy (LME) collimators to limit septal penetration and reduce shine-through [29 (link)]. SPECT images were reconstructed using clinical reconstruction software (Siemens Flash3D), with attenuation and scatter correction (6 iterations, 8 subsets, 5 mm Gaussian filter). For the 2-day protocol, ~ 120 MBq ^99mTc-nanocolloid or ~ 74 MBq ^99mTc-tilmanocept was administered, whereas for the single-day protocol, ~ 50 MBq ^99mTc-nanocolloid was administered.

Directly, post-injection planar images were acquired in dynamic mode (128 × 128 matrix, 20 frames of 1 min) in anterior-posterior projection followed by static mode (256 × 256 matrix, during 4 min) in anterior-posterior and lateral projections (30 min and 2 h post-injection), on a Siemens Symbia T16 SPECT-CT scanner, using ‘low- and medium energy’ (LME) collimators to limit septal penetration (reducing shine through) [16 (link)]. In addition to the planar imaging 2 h post-injection, SPECT-CT scans were acquired on a 128 × 128 matrix (pixel spacing, 3.9 × 3.9 mm), with 128 angles, 20 s per projection, over a non-circular 360° orbit (CT: 110 kV, 40 mAs eff., 16 × 1.2 mm). SPECT images were reconstructed using clinical reconstruction software (Siemens Flash3D), with attenuation and scatter correction (6 iterations, 8 subsets, 5-mm Gaussian filter). Additionally, quantitative SPECT reconstructions were generated using the Utrecht Monte Carlo System (UMCS), a dedicated SPECT reconstructor [17 (link), 18 (link)] which includes Monte Carlo modelling of scatter and collimator-detector interactions. During lymphoscintigraphy, a source with known radioactivity was scanned in the same frame as the patient, acting as a verification of quantitative accuracy.