| rad ("radiation absorbed dose"): a basic unit of the amount of radiation transferred to an object. This measurement does not take into account the type of radiation, which can influence the effect on different body tissues. The rad has largely been replaced by the gray. |
 |
|
|
| radiation dose: the amount of radiation an object (such as human tissue) receives. There are several units used to describe radiation doses. See also rad ("radiation absorbed dose"), gray, and rem ("roentgen equivalent man"). |
|
|
|
| radiation oncologist: a doctor who specializes in using radiation to treat cancer. |
|
|
|
| radiation therapist: a person with special training to work the equipment that delivers radiation therapy. |
|
|
|
| radiation therapy: treatment with high-energy rays (such as x-rays) to kill cancer cells and shrink tumors. The radiation may come from outside the body (external radiation) or from radioactive materials placed directly in the tumor (brachytherapy or internal radiation). Radiation therapy may be used to shrink the cancer before surgery, to destroy any remaining cancer cells after surgery, or as the main treatment. It may also be used as palliative treatment for advanced cancer. |
|
|
|
| radical prostatectomy: surgery to remove the entire prostate gland, the seminal vesicles, and nearby tissue. |
|
|
|
| radioactive implant: a source of high-dose radiation that is placed directly into or around a tumor to kill the cancer cells. See also brachytherapy. |
|
|
|
| radiocontrast dye: any material used in imaging studies such as x-rays, MRIs and CT scans to help outline the body parts being examined. These may be injected or ingested (drunk). Also called dye, contrast dye, radiocontrast medium. See also imaging studies. |
|
|
|
| radiofrequency ablation:
(ray-dee-oh-free-kwin-see uh-blay-shun):
treatment that uses high-energy radio waves to heat and destroy abnormal tissues. A thin, needle-like probe is guided into the tumor by ultrasound or CT scan. The probe releases a high-frequency current that heats and destroys cancer cells. RFA is sometimes used to treat tumors in the liver, and is being studied for use in several other areas of the body. |
|
|
|
| radioisotope:
(ray-dee-oh-EYE-suh-tope):
a type of atom that is unstable and prone to break up (decay). Decay releases small fragments of atoms and energy. Exposure to certain radioisotopes can cause cancer. But radioisotopes are also used to find and treat cancer. In certain imaging procedures, for example, radioisotopes are injected into the body where they then collect in areas where the disease is active, showing up as brighter areas on the pictures. See also imaging studies. |
|
|
|
| radiologic technologist: a health professional (not a doctor) trained to position patients for x-rays, take the images, and then develop and check the images for quality. The films taken by the technologist are sent to a radiologist to be read. |
|
|
|
| radiologist: a doctor with special training in diagnosis of diseases by interpreting or reading x-rays and other types of diagnostic imaging studies; for example, CT and MRI scans. |
|
|
|
| Radionuclide bone scan:
(ray-dee-oh-NOO-klide):
an imaging test which uses a small amount of radioactive contrast material given in the vein. The radioactive material settles in areas of the bone to which the cancer may have spread ("hot spots"), and shows up on the picture. See also imaging studies. |
|
|
|
| randomized or randomization: a process used in clinical trials that uses chance to assign participants to different groups that compare treatments. a process in clinical trials that uses chance to assign participants to different groups that compare treatments. Randomization means that each person has an equal chance of being in the treatment and comparison groups. This helps reduce bias in the results that might happen, if, for example, the healthiest people all were assigned to a particular treatment group. See also control group and clinical trials. |
|
|
|
| recurrence: the return of cancer after treatment. Local recurrence means that the cancer has come back at the same place as the original cancer. Regional recurrence means that the cancer has come back after treatment in the lymph nodes near the primary site. Distant recurrence is when cancer spreads (metastasizes) after treatment to distant organs or tissues (such as the lungs, liver, bone marrow, or brain). See also primary site, metastasis, and metastasize. |
|
|
|
| red blood cells: blood cells that contain hemoglobin, the substance that carries oxygen to all of the cells of the body. See also anemia. |
|
|
|
| regimen:
(reh-juh-men):
a strict, regulated plan (such as diet, exercise, or medicine schedule) designed to reach certain goals. In cancer treatment, a plan to treat cancer. See also protocol. |
|
|
|
| regional involvement or regional spread: the spread of cancer from its original site to nearby areas such as lymph nodes, but not to distant sites. See also metastasis. |
|
|
|
| rehabilitation: activities to help a person adjust, heal, and return to a full, productive life after injury or illness. This may involve physical restoration (such as the use of prostheses, exercises, and physical therapy), counseling, and emotional support. |
|
|
|
| relapse: reappearance of cancer after a disease-free period. See recurrence. |
|
|
|
| relative 5-year survival rate: the percentage of people with a certain cancer who have not died from it within 5 years. This number is different from the 5-year survival rate in that the relative 5-year survival rate does not include people who have died from unrelated causes. See also 5-year survival rate. |
|
|
|
| rem ("roentgen equivalent man"): a basic unit of radiation exposure which is based on both the dose and the type of radiation. Because of this, it is more commonly used to describe radiation exposure than is the rad. Often reported in units of millirem (mrem), which is one-thousandth of a rem. The rem is sometimes replaced by the sievert (see sievert). |
|
|
|
| remission: complete or partial disappearance of the signs and symptoms of cancer in response to treatment; the period during which a disease is under control. A remission may not be a cure. |
|
|
|
| rescue treatment: procedures or treatments such as bone marrow transplantation that "rescue" a patient's immune system and blood-forming organs from the effects of high-dose chemotherapy. |
|
|
|
| resection: surgery to remove part or all of an organ or other structure. |
|
|
|
| respiratory therapist: under the direction of a doctor, the respiratory therapist gives breathing treatments and helps manage patients on ventilators. |
|
|
|
| retinoids: vitamin A and synthetic compounds similar to vitamin A. |
|
|
|
| ribonucleic acid:
(ri-bo-new-CLEE-ick acid):
a nucleic acid found in all cells that transmits genetic messages between structures in the cell. Usually referred to as RNA. |
|
|
|
| risk factor: anything that is related to a person's chance of getting a disease such as cancer. Different cancers have different risk factors. For example, unprotected exposure to strong sunlight is a risk factor for skin cancer; smoking is a risk factor for lung, mouth, larynx, and other cancers. Some risk factors, such as smoking, can be controlled. Others, like a person's age, can't be changed. |
|
|
|
| RNA: See ribonucleic acid |
|
|
|
