MPRI — Glossary

Accelerated Therapy: Radiation treatment in which the total dose is given over a shorter period of time.

Adjuvant Therapy: A treatment used in addition to the main therapy.

Anesthesia: A drug administered for medical or surgical purposes that induces partial or total loss of sensation and may be topical, local, regional, or general, depending on the method of administration and area of the body affected.

Anesthesiologist: Medical doctor who specializes in administering anesthesia.

Aperture: A custom-made hole through which a proton beam that is contoured to the exact shape of the tumor in order to achieve greater accuracy passes.

Arch System/Bite Block: A device designed and constructed by a dentist to ensure immobility of a patient's head and neck region.

Benign Tumor: A non-cancerous tumor.

BID Treatment: Treatment that occurs twice daily. BID is an abbreviation for "bis in die," which means twice a day in Latin.

Biopsy: The removal of a tissue sample that is examined for the presence of cancerous cells.

Brachytherapy: Radiation therapy in which the radioactive material is placed in or close to the tumor being treated.

Bragg Peak: The burst of energy released by protons when they reach the tumor site.

Cancer: A term used to describe many different diseases, all of which involve the uncontrolled, abnormal growth of cells.

Catheter: A flexible or rigid tube used to drain fluids from body cavities or to distend body passages, especially one for passing into the bladder through the urethra to draw off urine or into the heart through a leg or arm vein for diagnostic examination.

Chemotherapy: The treatment of cancer using specific chemical drugs that are selectively destructive to malignant cells and tissues.

Compensator: A beam modifier that changes radiation output over a patient's changing contour.

Conformal Radiation Therapy: Treatment that uses a computer to contour the proton beam to the shape of the tumor to deliver the radiation dose more accurately.

Consultation: Initial evaluation by a physician.

Critical Structures: Healthy tissues or organs near the tumor that must be protected from high doses of radiation.

CT scan: Computed Tomography scan. A computerized procedure that produces images of the body that offer more detailed information than traditional X-ray images.

Cyclotron: An accelerator in which charged particles are propelled in spiral paths by the use of a constant magnetic field.

Dosimetrist: Radiation therapy practitioner responsible for production of the patient's treatment plan and any associated quality assurance components.

Endorectal Coil MRI: Involves the placement of a probe into the patient's rectum to allow technicians better visualization and detection of the spread of prostate cancer than with a conventional MRI.

Entrance Dose: A dose of radiation deposited near the surface of the body before the beam reaches the tumor.

Exit Dose: A dose of radiation deposited in healthy tissue after the tumor site is reached.

Fractionation: Division of the total treatment dose into smaller amounts to limit the body's exposure to radiation.

Gamma Knife: A medical device using the intercepting beams of gamma rays to treat brain tumors and lesions.

Gantry: A structure that rotates the proton beam delivery nozzle around the patient in order to treat him or her from different angles.

Gleason Score: Used to help evaluate the prognosis of men with prostate cancer. Together with other parameters, the Gleason score is incorporated into a strategy of prostate cancer staging, which predicts prognosis and helps guide therapy.

Gray: A measure of absorbed radiation dose. Also, one Gray equals 100 centiGray(cGy).

Immobilization Device: A custom-made device, such as a mold or mask, that keeps the patient stationary during treatment to ensure precise delivery of radiation doses.

Magnetic Resonance Imaging (MRI): A diagnostic procedure that uses a scanner to obtain detailed sectional images of the internal structure of the body.

Malignant: Progressive and uncontrolled growth, especially of a tumor.

Medical Physics: A branch of applied physics concerning the application of physics to medicine. It generally concerns physics as applied to medical imaging and radiotherapy, although a medical physicist may also work in many other areas of health care.

Medical Oncologist: A physician who uses chemotherapy to treat cancer.

Medical Physicist: Performs or supervises the pertinent procedures necessary to ensure the safe and effective delivery of radiation to achieve a diagnostic or therapeutic result as prescribed in patient care.

Metastasis: Spreading of cancerous cells from an original site to other places in the body.

Mixed Modality: A modality is a type of radiation treatment: X-rays, protons, etc. A treatment that consists of partly one modality followed by another is called a mixed modality.

Modulator Wheel: A device made of Lucite that is used to spread out the proton dose in depth by modulating the distribution of energies in the photon beam as the blades of the modulator rotate through it.

Nozzle: A piece of equipment through which the proton beam is delivered to the tumor.

Oncologist: A doctor who specializes in treating cancer.

Photon: A particle used in traditional X-ray radiation therapy.

Positron Emission Tomography (PET): A nuclear medicine imaging scan that can identify cancerous tissue that may not be visible on CT or MRI scans.

Prostate-Specific Antigen (PSA): A protein in the blood that can be measured to detect or monitor prostate cancer.

Protocol: A course of treatment designed to eradicate cancer.

Protons: Positively charged particles used in proton therapy to treat cancerous cells.

Proton Therapy: A pinpoint-accurate form of radiation therapy that uses protons instead of X-rays to target tumors more precisely.

Radiation: Energy transmitted as rays or waves that is used to treat cancer. Types of radiation include visible light, X-rays, and a proton beam.

Radiation Oncologist: A doctor who specializes in the use of radiation to treat cancerous or non-cancerous tumors. A radiation oncologist reviews the medical findings with the patient and discusses treatment options and the benefits of radiation as well as the possible side effects.

Radiation Therapist (RTT): A medical practicioner that sees the patient daily and is responsible for treatment delivery and daily assessment of patient tolerance to treatment.

Radiation Therapy: Radiation therapy uses high-energy, penetrating waves, or particles, to treat cancer cells.

Radiotherapy: Another term for radiation therapy (see above).

Registered Nurse (RN): A graduate nurse who has passed a state board examination and has been registered and licensed to practice nursing.

Robot Positioner: A robot that is adapted for the positioning of patients for radiotherapy treatments.

Side Effects: A peripheral or secondary effect.

Simulation: The use of X-rays to plan treatment through locating and marking the area to be treated.

Snout: The final extendable component of the nozzle that contains different beam-shaping devices.

Stationary Beam Line: Also called a fixed beam line. A beam line that cannot move around the patient (as opposed to a gantry, which is a moveable beam line).

Synchrotron: An accelerator in which charged particles are accelerated around a fixed circular path by an electric field and held to the path by an increasing magnetic field.

Targeting Markers (Fiducials/Seed Implant): Markers placed internally or at the skin surface to document location.

Tomotherapy: A modality of photon radiation treatment that combines the use of computer-controlled radiation beam collimation with an on-board computed tomography (CT) scanner to image the treatment site.

Treatment Field: The area in the body to be treated by the radiation beam.

Treatment Planning: The process by which beam delivery is optimized for a given patient and clinical situation.

Tumor: An abnormal growth of tissue resulting from the uncontrolled, progressive multiplication of cells.

Verification Simulation (V-Sim): A final check that each of the planned treatment beams covers the tumor or target volume and does not irradiate normal tissue.