Radiation Therapy Extra Vocabulary

A complete set of vocabulary flashcards covering terms, techniques, and compositions used in radiation therapy planning and delivery.

AP/PA

A 2-field treatment with two parallel opposed beams entering from the anterior surface and posterior surface of the patient.

Boost fields

Fields that are used to deliver a high dose to a small volume, generally delivered to the gross tumor volume only, excluding regional lymph nodes and organs at risk (OAR).

Cerrobend

A form of Lipowitz metal used for designing custom shielding blocks and electron cut-outs and consists of $50.0\%$ bismuth, $26.7\%$ lead, $13.3\%$ tin, and $10.0\%$ cadmium.

Collimator field size

Unblocked or open field size as defined by the collimator setting and projected at the reference distance, usually the isocenter of the linear accelerator.

Elapsed days

Total time over which radiation treatment is delivered (protracted).

Isocentric technique

Approach to three-dimensional treatment using multiple imaging modalities, including fluoroscopy, CT, MRI, PET, SPECT, and ultrasound, planning where the isocenter is placed in or near the target volume.

Metastases

Spread of cancer beyond the primary site.

Metastasize

Process of tumors spreading to a site in the body distant from the primary site.

Shielding

Material that is used to limit the exposure to ionizing radiation.

Shrinking fields

Technique that reduces the treated field area one or more times during the course of treatment in response to a tumor that reduces in size and/or the need to limit doses to normal structures.

Simulation

In cancer treatment, a process used to plan radiation therapy so that the target area is precisely located and marked, commonly performed with CT simulation.

Staging

The process of determining the anatomic extent of the disease after a histologic diagnosis is made.

Tangent

The value equal to the length of the opposite side divided by the length of the adjacent side, expressed as $\tan(\theta) = \frac{\text{opposite}}{\text{adjacent}}$.

Tissue Tolerance

The dose point that tissues can tolerate which if exceeded will lead to serious side effects or consequences.

Treatment console

Operating center where timers and system-monitoring indicators are displayed.

Treatment field (portal)

Volume exposed to radiation from a single radiation beam.

Treatment technique

Defined method by which a treatment is delivered to the patient.

X-ray

Electromagnetic radiation produced when a fast electron stream hits a target, where the synergy of the resultant beam increases with the voltage that accelerates the electrons.