Somatom definition flash ct scanner

A SOMATOM Definition Flash CT scanner (Siemens Healthineers, Erlangen, Germany) was utilized for all patients. An a priori performed non-contrast pelvis CT (for pzPC patients) or thoracic CT (for NSCLC patients) was used for planning, in which the prostate or index lesion (for NSCLC patients) was delineated. After i.v. injection of 40 mL of non-ionic iodinated contrast agent at an injection rate of 5 mL/second (Iomeron 400, Bracco Imaging, S.p.A., Rome, Italy), followed by a saline chaser of 40 mL, 26–33 scans of the prostate or 20–30 scans of the tumor in the thorax were acquired. The first 20 examinations were performed at 1.5 s intervals, and the following scans at 3 s intervals, to reduce the radiation dose after the initial arterial influx. A tube voltage of 80 or 90 kVp was used, depending on patient body weight. Slice width was 5 mm for prostate scans and 1.5 mm for lung scans, rotation time 0.25 s, slice collimation 48 × 1.2 mm; and scan length was 114 mm for prostate scans, and 110 or 174 mm for lung scans.

The patient underwent ECG-gated CT imaging preoperatively, 11 days postoperatively and 5.5 months postoperatively. The scans were performed on a Somatom® Definition Flash CT scanner (Siemens Healthcare, Erlangen, Germany) during breath-hold, with the patient in supine, feetfirst position, and administration of 80 mL intravenous contrast agent (Visipaque 320 mg I/mL, GE Healthcare, Chicago, IL, USA) administered at 4 mL/second. The CT rotation time was 0.3 s, with collimation 64 × 0.6 mm, slice thickness 1 mm, slice increment 0.5 mm, reconstruction matrix 512 × 512 pixels, convolution kernel i36f, pixel size ranging 0.6 × 0.6 − 0.8 × 0.8 mm, tube voltage 120 kV with automated tube current modulation and automated pitch factor based on the heart rate. Retrospective gating allowed reconstruction of 10 equally sized CT volumes, representing 10 phases of the cardiac cycle from 0 to 90% of the R–R interval. A previously established image registration algorithm^{5 (link),8 (link)} was used to obtain a phase-averaged CT volume and 10 deformation fields. The deformation fields can be used to translate voxels of the phase-averaged CT volume to the corresponding locations in the 10 cardiac phases. This allowed a single measurement to be translated to each cardiac phase and thereby diminish the observer dependence.