Cryotherapy (also called cryoablation or cryosurgery) uses extreme cold for the treatment of disease. A cryoprobe applies the cold to the selected anatomic area, for example the prostate.

See also Brachytherapy, RF Thermal Ablation, High Intensity Focused Ultrasound and Prostate Ultrasound.

(CTA) A computed tomographic angiography or computerized tomography angiogram is a diagnostic imaging test that combines conventional CT technique with that of traditional angiography to create images of the blood vessels in the body - from brain vessels to arteries of the lungs, kidneys, arms and legs.
High resolution CT scans with thin slices and intravenous injection of iodinated contrast material provide detailed images of vascular anatomy and the adjacent bony structures. CTA requires rapid scanning as the imaging data are typically acquired during the first pass of a bolus of contrast medium. The selection of acquisition timing is important to optimize the contrast enhancement, which is dependent on contrast injection methods, imaging techniques and patient variations in weight, age and health. CT angiography is less invasive compared to conventional angiography and the data can be rendered in three dimensions.

CTA techniques are commonly used to:
See also Cardiovascular Imaging, Magnetic Resonance Angiography MRA, Coronary Angiogram, Computed Tomography Dose Index and Computed or Computerized Axial Tomography.

CAT/CT guided biopsies and other minimally invasive interventions are well established medical procedures. Since the beginning of computed tomography, conventional CAT/CT imaging studies has been used to guide an interventional procedure such as a tissue biopsy of a suspected tumor or metastases.
Advanced interventional CT scanners provide fluoroscopic techniques allowing additionally the guidance of minimally invasive surgery or micro-therapy. Fluoro CT allows the continuous monitoring of the needle trajectory or inserted surgical instrument. A wide gantry opening, external tilting laser for needle guidance and special software ease the intervention.
CT images are also used to plan radiotherapy cancer treatment and determine how the disease is responding to the treatment.

(Computed tomography number) The CT number is a selectable scan factor based on the Hounsfield scale. Each elemental region of the CT image (pixel) is expressed in terms of Hounsfield units (HU) corresponding to the x-ray attenuation (or tissue density).
CT numbers are displayed as gray-scale pixels on the viewing monitor. White represents pixels with higher CT numbers (bone). Varying shades of gray are assigned to intermediate CT numbers e.g., soft tissues, fluid and fat. Black represents regions with lower CT numbers like lungs and air-filled organs.

A computed tomography (CT) power injector (also named pressure injector) is used to deliver contrast agents during CT imaging procedures with high-flow, high-volume, fixed-rate injection at relatively high pressures. The use of power injectors allows precise administration of contrast agent to obtain consistent high quality CT images. A dual-head CT power injector permits loading of contrast and saline onto the same injector. Contrast injection systems manage injector protocol data, improve patient safety, and workflow efficiency. When combined with pressure monitoring systems and hardware to prevent extravasation (accidental leakage of IV material into the surrounding tissue) these CT injectors can simultaneously mitigate risk.

See also Contrast Media Injector, Single-Head CT Power Injector, Multi-Head Contrast Media Injector, Syringeless CT Power Injector.