Study of Low Dose CT in Sarcoma Patients

Surveillance Low Dose Computed Tomography of the Thorax in Patients With High Grade Extremity Soft Tissue Sarcoma

The primary outcome of this study is the detection of lung metastases comparing Low dose CT (LDCT) and Minimum dose CT (MnDCT) with CXR. Hypothesis LDCT and MnDCT have similar sensitivity for the detection of lung nodules (metastases). MnDCT of the thorax detects a larger number of nodules (metastases) than CXR.

A 3-year prospective phase II non-randomized study commenced May 2003 enrolling 60 high-risk patients with Intermediate and High Grade STS. Each patient is kept under radiological surveillance for 3 years unless lung metastases are detected. Conventional thoracic imaging for staging and surveillance of STS patients is shown in Figure 1. In the trial, LDCT and MnDCT are added to each imaging visit (Figure 1). A 2-view CXR (CR) is performed (Direct View, Kodak, Rochester) followed by thoracic CT scans performed on a Siemens 16 row MDCT (Sensation 16, Siemens, Erlangen), CT acquisition; 120kVp, 5/2.5/2.5mm. Images are reconstructed with high and low spatial frequency filters and soft copy viewing is performed on a standalone PACS workstation using standard mediastinal (w 350, l 40) and lung (w 1500, l -600) settings. Examinations are performed with varying mAs; SDCT 120 mAs, LDCT 40 mAs and MnDCT 20 mAs. The examinations are evaluated, blinded to the results of the alternative and previous studies, for the presence of nodules (defined as a non-calcified focal opacity ≥3 mm < 3 cm). Surveillance imaging is commenced 3 months post surgery.