Computed Tomography Dose Reduction Using Sequential or Fast Pitch Sprial Technique (CT DOSE)

• Radiation dose [ Time Frame: Time of CT scan ] [ Designated as safety issue: Yes ]
  The primary endpoint is radiation dose, measured as dose-length-product (DLP, in mGy∙cm) and effective radiation dose, calculated as DLP x 0.014 (in mSv).
  
  

• Assessment of Image Quality [ Time Frame: Time of CT Scan ] [ Designated as safety issue: No ]
  Signal noise (standard deviation of attenuation in Hounsfield units) will be determined in regions of interest in: A) air anterior to the chest wall, B) mid-LV septum and C) mid thoracic aorta or main PA. This will be done in a sequential sample of every 5th case (approximately 600 cases total).
  
  

The development of a novel CT scanner capable of sequential or fast-pitch spiral techniques in most patients (Siemens Definition Flash) represents a potentially crucial technical innovation at a particularly critical juncture. National healthcare systems are under pressure to deliver accurate and cost-effective diagnosis of an increasing number of patients and CT angiography in various settings is a proven, highly accurate technique that has been shown to improve diagnostic efficiency and reduce the cost of care.

However, there has been increasing concern about the lifetime attributable risk of cancer from radiation related to diagnostic procedures. Such concern extends to other radiation-based procedures that contribute to the cumulative lifetime radiation exposure of patients. The Flash scanner holds the promise of substantially reducing exposure resulting from a variety of examinations.

The CT DOSE multicenter trial is therefore designed to validate the extent of dose reduction attendant to the use of the Flash scanner in cardiothoracic scanning, and to determine whether image quality is preserved in spite of significant dose reduction.