Radiation Oncology Vocabulary – Flashcards
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Amount of radiation absorbed per unit of mass of irradiated material.
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Absorbed dose
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Device that accelerates charged subatomic particles to great energies.
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Accelerator (particle)
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Four independent x-ray collimators that are used to define radiation treatment field.
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Asymmetric jaws.
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Removal of energy from a beam of radiation when it traverses matter, accomplished by disposition of energy in matter and by deflection of energy out of the beam.
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Attenuation
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Electron accelerator that uses magnetic induction to accelerate electrons in circular path; also capable of producing photons.
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Betatron
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Removal of a small piece of tissue for examination under the microscope.
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Biopsy
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Placement of radioactive nuclide or nuclides in or on a neoplasm to deliver a cancericidal dose.
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Brachytherapy
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Dose of radiation that results in the death of cancer cells.
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Cancericidal dose
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Any cancer producing substance or material, such as nicotine, radiation, or ingested uranium.
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Carcinogen
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Cancer that arises from epithelial tissue- either glandular or squamous epithelium.
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Carcinoma
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Beam shaping device made of a lead alloy that attenuates the beam, preventing exposure of normal tissue.
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Cerrobend Block
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Unit of genetic information that guides cytoplasmic activities of the cell and transmits hereditary information.
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Chromosome
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Radioisotope with half life of 5.26 years, average gamma ray energy of 1.25 MeV, and ability to spare skin with buildup depth in tissue of 0.5 cm.
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Cobalt 60
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Diaphtragm or system of diaphragms made of radiation absorbing material that defines dimension and direction of beam.
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Collimator
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Treatment designed to deliver radiation to the exact target volume as seen on any plane; requires a 3D treatment planning system.
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Conformal radiation
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Reproduction of an external body shape, typically in the transverse plane at the level of the central axis of the beam; facilitates planning of radiation treatment. Other planes of interest may also be obtained.
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Contour
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Usually a 5 year period after completion of treatment during which time the patient exhibits no evidence of disease.
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Cure
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Transformation of radioactive nucleus, resulting in emission of radiation.
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Decay or disintegration
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Acquisition of cellular function and structure that differs from function and structure of original cell type.
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Differentiation
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Radiation that interacts with an organic molecule such as DNA, RNA, or a protein molecule. This interaction may inactivate the cell.
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Direct Effect
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Measurement of radiation dose in an absorbing medium.
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Dosimetry
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Cells that line the surfaces of serous and mucous membranes, including the skin.
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Epithelial tissue
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Study of causes of diseases.
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Etiologyy
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Delivery of radiation to a patient from a unit such as a linear accelerator in which the radiation enters the patient from the external surface of the body.
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External beam treatment
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Geometric area defined by collimator or radiotherapy unit at skin surface.
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Field
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Division of total planned dose into numerous smaller doses to be given over a longer period. Consideration must be given to biologic effectiveness of smaller doses.
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Fractionation
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Electromagnetic radiation that originates from radioactive nucleus and causes ionization in matter; identical properties to x-ray.
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Gamma Ray
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International unit for the quantity of radiation received by the patient; previously rad.
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Gray
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X-rays generated at 20 kVp or less.
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Grenz Rays
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Time required for radioactive material to decay to half its initial activity; types are biologic and physical.
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Half life
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Thickness of attenuating material inserted in beam to reduce beam intensity to half of the original intensity.
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Half value layer
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Use of a high activity radionuclide placed within the body for the treatment of cancer. Delivers more than 1200 cGy per hour.
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High dose rate brachytherapy
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Use of images to verify treatment isocenter, target, and patient positioning before initiating radiation treatment.
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Image guided radiation therapy
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X-ray collimator with four individual blades that can be moved independently of one another.
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Independent jaws
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Interaction of radiation with water molecules within the cell; results in the formation of free radicals OH, H, and HO2, which can damage the cell.
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Indirect effect
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Process in which one or more electrons are added to or removed from atoms, creating ions; can be caused by high temperatures, electrical discharges, or nuclear radiations.
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Ionization
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Energy emitted and transferred through matter that results in the removal of orbital electrons (e.g., x-rays or gamma rays)
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Ionizing radiation
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Modification of beam intensity to deliver nonuniform exposure across radiation field.
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Intensity modulated radiation therapy
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Referring to rotation around a fixed point.
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Isocentric
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Curve or line drawn to connect points of identical amounts of radiation in a given field.
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Isodose line curve
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Atoms that have the same atomic number but different mass number.
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Isotope
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Morbid change in tissue; mass of abnormal cells.
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Lesion
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Device for accelerating charged particles, such as electrons, to produce high energy electron or photon beams.
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Linear accelerator (linac)
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Rate at which energy is deposited as it travels through matter.
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Linear energy transfer (LET)
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Use of a low activity radionuclide placed within the body for treatment of cancer.
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Low dose rate brachytherapy
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Cancerous tumor or lesion.
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Malignany
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person responsible for calculation of proper radiation treatment dose who assists the radiation oncologist in designing individual treatment plans.
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Medical dosimetrist
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Specialist in the study of the laws of ionizing radiation and their interactions with matter.
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Medical physicist
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Transmission of cells or groups of cells from primary tumor to sites elsewhere in the body.
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Metastasis
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Individual collimator rods within the treatment head of the linear accelerator that can slide inward to shape radiation field.
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Multileaf collimator
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Physician specializing in the study of tumors.
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Oncologist
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Study of tumors.
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Oncology
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To relieve symptoms; not for cure.
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Palliation
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Specialist in the study of the microscopic nature of disease.
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pathologist
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Preventive surgical treatment.
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Prophylactic surgery
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Physician specializing in use of radiation in treatment of disease.
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Radiation oncologist
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Medical specialty involving the treatment of cancerous lesions using radiation.
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Radiation oncology
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Person trained to assist and take directions from the radiation oncologist in the use of radiation for treatment of disease.
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Radiation therapist
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Older term used to define medical specialty of treatment with radiation.
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Radiation therapy
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Pertaining to atoms of elements that undergo spontaneous transformation, resulting in emission of radiation.
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Radioactive
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Susceptibility of neoplastic cells to cure (destruction) by radiation.
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Radiocurable
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Responsiveness of cells to radiation.
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Radiosensitivity
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A radionuclide used clinically for radiation therapy. In conjunction with its subsequent transformations, it emits alpha and beta particles and gamma rays. In encapsulated form, it is used for various intravacitary radiation therapy applications.
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Radium (Ra)
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Cubicle in which isotopes are artificially produced.
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Reactor
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Compares radiation beams with different LETs and their ability to produce a specific biologic response. Dose in Gray from 250 kVp beam of x-rays/dose from another type of radiation to produce the same effect.
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Relative Biologic Effectiveness (RBE)
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Diagnostic machine that has the same geometric and physical characteristics as a radiation therapy treatment unit.
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Simulator
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In megavoltage beam therapy, reduced skin injury per centigray exposure because electron equilibrium occurs below skin; occurs 1/4 to 2 inches deep, depending on energy.
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Skin Sparing
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Use of small focused radiation beams to treat small extracranial or intracranial lesions; delivered with conventional fractionation or in two to five treatments instead of a single treatment as in sterotactic radiosurgery. Rigid immobilization of patient is required.
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Stereotactic radiation therapy
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Use of multiple, narrow, highly focused radiation beams to deliver a large dose in a single treatment to a small intracranial lesion. The patient is immobilized with a fixed stereotactic head frame.
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Stereotactic radiosurgery
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Area of excision and adjacent tissues manipulated during surgery.
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Surgical bed
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Throughout the human body.
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Systemic
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Radiation therapy technique for which source of radiation is at some distance from patient.
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Teletherapy
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Anatomic area outlined for treatment.
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Treatment field
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Portion of anatomy that includes tumor and adjacent areas of invasion.
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Tumor/target volume
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Lack of resemblance of cells to cells of origin.
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Undifferentiation
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Wedge shaped beam attenuating device used to absorb beam preferentially to alter the shape of the isodose curve.
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Wedge filter
