The calcium score reflects the degree and extent of calcium deposits in the walls of the coronary arteries. The calcium score can be measured by cardiac computed tomography.

A calibration is a correction procedure that determines the relationship between the measured output of a system and the reference standard. Calibration procedures include scanning air or an appropriate test phantom.
The calibration of a CT system takes account of variations in beam intensity or detector efficiency in order to achieve best homogeneity within the field of view and the accuracy of CT numbers.

See also Calibration Factor and Acceptance Checking.

The calibration factor helps to convert between the measured value of a parameter and the actual value of that parameter in a system.
This normalization is necessary in cases where detectors and sensors do not directly sample a parameter, for example the radiation energy is measured by a detector that produces an electrical pulse whose total charge is proportional to the supplied radiation.

Cancer is a general term related to the abnormal (malignant) growth of cells (tumor) which tend to proliferate uncontrolled and destroy healthy tissues. If not controlled by effective treatment, cancer can spread out into other regions of the body (metastasize).
Ductal carcinoma in situ (DCIS): A form of breast carcinoma in situ confined to the breast ducts. DCIS (also called noninvasive breast cancer or intraductal breast carcinoma) is often associated with microcalcification on mammography.

The cardiac catheterization requires the passage of a small catheter through an arm or leg vessel into the heart, in order to permit the securing of blood samples, determination of intracardiac pressure, detection of cardiac anomalies, and injection of contrast media for angiography.