Ct scanners

For this study, we retrospectively obtained patient data for 10 patients with histologically verified NSCLC. The Institutional Review Board (IRB) at the University of Texas MD Anderson Cancer Centers approved the present retrospective study, and the requirement for informed consent was waived. The lung tumors included in this study had volumes ranging from 1.15 cm³ to 10.53 cm³. For each patient, breath-hold helical computed tomography (CT) scans were acquired with intravenous contrast. The CT scans were acquired on General Electric Healthcare CT scanners with a peak tube voltage of 120 kVp and tube currents ranging from 320 mAs to 570 mAs. Each scan was reconstructed with a slice thickness of 2.5 mm and pixel spacing between 0.635 mm and 0.977 mm. Fig 1 shows a coronal slice of each tumor to display the variety of tumor presentations and locations of this patient cohort.

All CT scans were performed prior to any treatment for lung cancer using two CT scanners (GE Healthcare, Milwaukee, WI, USA; United Imaging, Shanghai, China). The scanning parameters were as follows: the tube voltage, 120 kVp; tube current, 160–300 mA; detector collimation, 64 or 128 × 0.625 mm; field of view, 350 × 350 mm; the pitch, 0.992:1; and matrix of 512 × 512. All images were reconstructed with a section thickness of 2 mm and subsequently stored in DICOM format in the Picture Archiving and Communication Systems (PACS) using mediastinal (width, 360 HU; level, 50 HU) and lung (width, 1500 HU; level, -650 HU) window settings.

This section describes the scanning protocol.
Before scanning, we informed the patient and family members of the precautions during scanning and the risk of contrast injection. The scan will only be performed after the patient or family members have signed the informed consent form. Before the start of the scan, we will perform breathing exercises on the patient to reduce the influence of scanning motion artifacts. The patient took a supine position during the scan, with his hands raised above the top of his head, and was scanned from the entrance of the thorax to the bottom of the lung.
All contrast-enhanced chest CT images were acquired (on two GE Healthcare CT scanners) with the following parameters: 120 kV tube voltage, 300 mA effective power of tube, 1.375 pitch, 0.6 s/cycle rotation speed, 5 mm reconstruction slice thickness, 5 mm reconstruction slice interval, and 512 × 512 matrix. All images were scanned in a craniocaudal sense. Intravenous contrast media (1 mL/kg) was injected at a rate of 3.5 mL/s. The iodine contrast medium concentration used during CT scanning was 300 mg/mL. During the CT scanning, the bolus tracking was used, and the ROI was positioned on the descending aorta.
According to the position and size of the chest in the image, the field of view was uniformly set to 400 × 300.