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.

A gallium scan uses a small amount of radioactive gallium-67 to show areas of infection and inflammation as well as certain types of cancer.

See also Abscess Scintigraphy and Gallium Scintigraphy.

Radiation can ionize matter caused by the high energy which displaces electrons during interactions with atoms. In the electromagnetic spectrum higher frequency ultraviolet radiation begins to have enough energy to ionize matter.
Examples of ionizing radiation include alpha particles, beta particles, gamma rays, x-rays, neutrons, high-speed electrons, high-speed protons, and other particles capable of producing ions by direct or secondary processes in passage through tissues.
Damage of living tissue results from the transfer of energy to atoms and molecules in the cellular structure. Ionized cells have to repair themselves to remain alive. Generally, healthy cells have a higher capability to repair themselves than cancer cells.

Biological effects of ionizing radiation exposure:
Ionizing radiation are used in a wide range of facilities, including health care, research institutions, nuclear reactors and their support facilities, and other manufacturing settings. These radiation sources can pose a serious hazard to affected people and environment if not properly controlled.

See also Radiation Safety, Controlled Area, Radiotoxicity and As Low As Reasonably Achievable.

(LINAC) [Linear Particle Accelerator]
An electrical device that creates high-energy radioactive materials to treat cancers. It uses electricity to form a fast-moving linear stream of subatomic particles to collide with the target. LINACs for medical use produce a beam of 6-30 MeV energy.

The term malign (malignant) is used to describe cancerous cells.