Clinical Radiation Oncology (RAD-102A)

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

Treatment with drugs that kill cancer cells.

Having to do with the examination and treatment of patients.

A procedure that uses a computer to create a picture of a tumor to help guide the radiation beam during radiation therapy. The pictures are made using CT, ultrasound, X-ray, or other imaging techniques. Image-guided radiation therapy makes radiation therapy more accurate and causes less damage to healthy tissue. Also called IGRT.

Intensity-modulated radiation therapy is a 3-dimensional conformal radiation therapy planning and delivery tool that shapes the radiation dose distribution and minimizes the dose to normal structures. Intensity-modulated radiation therapy implies inverse planning algorithms (i.e., the physician determines radiation treatment parameters to maximize dose to the target and minimize dose to normal tissues, and the planning algorithm maximizes the adherence to these parameters by modifying the beam spatially and/or temporally). Spatial and temporal beam modification is often achieved by dynamically moving multi-leaf collimators. Intensity-modulated radiation therapy can also be achieved via custom-made beam compensators, which are derived from inverse planning algorithms. A novel way to deliver intensity-modulated radiation therapy is tomotherapy, in which a bank of collimated leaves shutter open and closed while rotating around the patient in a spiral manner. The unifying principle of all intensity-modulated radiation therapy planning and delivery methods is inverse planning. Intensity-modulated radiation therapy results in a greater deposition of low doses to normal tissue, which may increase the risk of second malignancies. Also called IMRT.

A measure of volume for a liquid, using the metric system. One L is equal to 1,000 cubic centimeters (cc), 1,000 milliliters (mm), or 1.0567 quarts (qt). Also called liter.

A machine that uses electricity to form a stream of fast-moving subatomic particles. This creates high-energy radiation that may be used to treat cancer. Also called linac, mega-voltage linear accelerator, and MeV linear accelerator.

Refers to the practices and procedures used for the prevention, treatment, or relief of symptoms of a diseases or abnormal conditions. This term may also refer to a legal drug used for the same purpose.

The study of cancer.

Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).

Radiosurgery implies the delivery of a single, high dose of radiation using stereotactic techniques. Classically, for cranial radiosurgery, a rigid neurosurgical frame is attached to the patient’s skull, and a stereotactic localizing device is attached to the frame to allow for improved targeting accuracy. Commercial radiosurgery systems are available in which immobilization is achieved without a rigid neurosurgical frame. While there are innumerable commercial radiosurgery and stereotactic radiation therapy systems, all of these systems utilize the same underlying principles: (1) patient immobilization, (2) targeting accuracy, (3) delivery of high doses of radiation, and (4) heterogeneous dose distribution with a steep dose gradient. Commercial radiosurgery systems include Gamma Knife, which utilizes 201 radioactive cobalt sources positioned in a semispherical array, and Cyberknife, which utilizes robotics technology allowing the linear accelerator (LINAC) to track the patient position in real time during treatment. A standard LINAC can be equipped with cones attached to its head, allowing for circular collimation of the beam. The dose distribution from Gamma Knife, Cyberknife, or a standard LINAC equipped with cones is spherical, and thus treating nonspherically shaped targets requires the superposition of multiple spherical dose distributions. A LINAC equipped with multi-leaf collimators can also be used for radiosurgery, which allows more conformal beam shaping. Also called radiation surgery, stereotactic radiosurgery, and stereotaxic radiosurgery.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiotherapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiation therapy.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

Treatment.

A legal document in which a person states what is to be done with his or her property after death, who is to carry out the terms of the will, and who is to care for any minor children.