safety - To ensure every patient is treated the best way, radiation oncologists have many checks and balances as part of treatment to ensure safety. Patients are encouraged to ask their treatment teams about the quality assurance programs where they are receiving radiation therapy. -

saline - Salt water. -

sarcoma - A malignant or cancerous tumor that occurs in the connective tissues of the body, including the bones, cartilage, tendons and soft tissues. -

scan(s) - To survey by traversing with an active or passive sensing device. , The image, record, or data obtained by scanning, usually identified by the technology or device employed; e.g., CT scan, radionuclide scan, ultrasound scan, etc. , Abbreviated form of scintiscan (scintigraphy), usually identified by the organ or structure examined; e.g., brain scan, bone scan, etc. , -

sciatica - Painful inflammation of the sciatic nerve that sometimes results from a herniated intervertebral disc in the spine. -

scintigraphy - (sin-tig-ru-fE) - A diagnostic procedure consisting of the administration of a radionuclide with an affinity for the organ or tissue of interest, followed by recording the distribution of the radioactivity with a stationary or scanning external scintillation camera. -

sclerosing - Liquid chemicals or alcohols used to destroy blood vessels in an embolization procedure. Sclerosing damages the inner lining of a vessel and causes blood clots (a thickened mass of blood) to form, thus preventing blood flow through the vessel. -

sclerosing cholangitis - Inflammation of the bile ducts. -

sclerotherapy - Treatment involving the injection of a sclerosing (hardening) solution into vessels or tissues. -

scoliosis - A lateral curvature of the spine that usually develops in childhood or adolescence. -

screening mammography - Imaging examination of the breast by means of x-rays, of individuals usually without symptoms to detect those with a high probability of having breast disease.

scrotum - A muscular sac that contains the testes. -

secure sockets layer (SSL) - A cryptographic communications protocol that provides secure transmissions on the Internet by encoding/decoding the data transfers. -

sedation, deep - A deep level of sedation, in which patients will generally sleep during the procedure without responding to painful stimulation. Patients will be able to breathe on their own and in many cases will receive oxygen from a face mask. See sedation, minimal and moderate. -

sedation, minimal and moderate - Levels of sedation in which the patient receives a drug to relax but remains responsive to verbal questions and painful stimulation. Patient is able to breathe independently during a surgical or medical procedure. See sedation, deep. -

sedation, non -pharmacological - Approaches that guide a patient to a state of relaxation by focusing attention on pleasant thoughts. Guidance is provided by specially trained radiology or other medical personnel. This condition may be achieved via distraction techniques or selfhypnotic relaxation.

sedative - A drug that allows you to relax during a procedure like angiography, often without putting you to sleep. -

seed implantation - See permanent brachytherapy. -

seeds - Radioactive pellets, approximately the size of a grain of rice, used in brachytherapy. -

seizure disorders - A condition marked by sudden, uncontrollable waves of electrical activity in the brain, causing involuntary movement or loss of consciousness. -

semen - (sE-men) - A thick white fluid, made and stored in male testicles, that carries sperm out of the body through the penis during ejaculation.

sentinel lymph node - The first lymph node in a lymph node bed to receive drainage from a tumor site. -

serial paracentesis - A minimally invasive procedure in which excess fluids in the abdomen are repeatedly withdrawn, either through a needle inserted directly into the peritoneal cavity or through a catheter connected to a peritoneal port, a small reservoir or chamber surgically implanted under the skin near the abdomen. -

sheath - A short, hollow plastic tube inserted through the skin into a blood vessel or tissue through which other instruments, such as a guide wire and balloon-tipped catheter are advanced.

short -bore MRI system - A type of magnetic resonance imaging (MRI) unit. The traditional MRI unit is a large cylindershaped tube surrounded by a circular magnet. The patient lies on a moveable examination table that slides in the center of the magnet. The short-bore system is designed so that the body part that is being scanned remains in the magnet. The short-bore nature of the magnet allows the body part not being scanned to potentially be "outside" of the magnet. Patients often report the short-bore MRI system is less claustrophobic than a traditional MRI unit. -

sickle -cell anemia - A severe, chronic type of anemia caused by an abnormal form of hemoglobin that distorts the red blood cells.

simulation - The process of planning radiation therapy to allow the radiation to be delivered to the intended location. Use of a radiographic system or computer to plan radiation therapy. See also treatment planning. -

sinus (sinuses) - Hollow, air-filled spaces located within the bones of the face surrounding the nasal cavity. There are four pairs of cavities, called paranasal sinuses, each of which is connected to the nose by small openings.

sinusitis - Infection or inflammation of one or more of the sinuses. -

sloughing - The process in which dead tissue becomes separated from living anatomic structures.

small intestine - The section of the gastrointestinal tract that digests food and absorbs nutrients after they have passed through the stomach. -

smartCards - A device similar to a credit card that contains electronic information or tokens that identify and validate a user in conjunction with biometric or password information. -

social workers - Social workers may be available to provide practical help and counseling to patients or members of their families. They can help a patient and family members cope. They also may help arrange for home health care and other services. Social workers may be licensed. Licensed social workers must have a master's degree. They also must pass an examination. -

sonographer - (so-nog-ru-fer) - An allied health professional who has been specifically trained to perform ultrasound examinations. Many sonographers are certified by a registry of sonographers, provided they meet strict training requirements and pass examinations in basic ultrasound science and clinical applications. -

sonography - (so-nog-ru-fE) - The location, measurement, or delineation of deep structures by measuring the reflection or transmission of high frequency or ultrasonic waves. Computer calculation of the distance to the sound reflecting or absorbing surface plus the known orientation of the sound beam gives a two- or three-dimensional image. Syn: ultrasonography.

sonohysterography - Sonography of the uterus and fallopian tubes using a transvaginal probe following the injection of sterile saline into the uterus. -

spectral Doppler - Instead of displaying Doppler measurements visually as in the color and power Doppler methods, spectral Doppler displays the blood flow measurements graphically, in terms of the distance traveled per unit of time. -

speculum - (spek-yU-lum) - An instrument for enlarging the opening of any canal or cavity in order to facilitate inspection of its interior.

sperm - Sperm (or spermatozoa) is the male reproductive cell carried by semen through the penis when a man ejaculates. -

sphincterotomy - A procedure in which a small incision is made in the opening of the bile duct to allow bile and small gallstones to drain. -

spinal anesthesia - Administration of a local anesthetic into the subarachnoid space, a fluid filled space surrounding the spinal cord. Generally used to prevent pain and movement in areas below the chest and extending to the feet. -

spinal canal - The cavity within the vertebral column through which the spinal cord passes. -

spinal cord - A cylindrical bundle of nerves, lying within the vertebral column, that carries sensory messages from peripheral nerves to the brain, and motor impulses from the brain to the body's muscles. -

spinal fusion - Surgical fixation of an unstable segment of the spine. -

spleen - (splEn) - A large vascular lymphatic organ lying in the upper part of the abdominal cavity on the left side, between the stomach and diaphragm. It is a blood-forming organ in early life and later a storage organ for red corpuscles and platelets; because of the large number of macrophages, it also acts as a blood filter.

splenoportography - (splE-nO-pOr-tog-ru-fE) - Introduction of radiopaque material into the spleen to obtain an x-ray visualization of the portal vessel of the portal circulation.

spot films - X-rays of a localized region, usually under study by fluoroscopy.

squamous Cell Carcinoma - The second most common cancer of the skin. Squamous cell carcinoma develops in the outer layer of the skin (the epithelium). -

stage - Extent or progression of a disease such as cancer. -

staging - Determining the extent or progression of a disease such as cancer. -

stenosis, pl. stenoses - (sten-Osis, sten-OsEs) - A stricture of any canal; especially, a narrowing of one of the cardiac valves., Narrowing of an opening or passageway in the body. Stenosis of an artery may reduce blood flow through the vessel., -

stent - A spacer used to push tissue to a specific position relative to the radiation treatment volume. -

stent - Device used to maintain a bodily orifice or cavity during skin grafting, or to immobilize a skin graft after placement. , Slender thread, rod, or catheter, lying within the space in the interior of a tubular structure, such as an artery or the intestine. Used to provide support during or after opening surgically, or to assure the opening of an intact but contracted lumen. , A semi-rigid tube-like device used to keep an artery open after angioplasty.,

stenting - The act of placing a stent. -

stereotactic biopsy - An x-ray procedure that uses multiple coordinates to precisely determine the location of a tumor or nodule so that a tissue sample may be obtained.

stereotactic Body Radiation Therapy (SBRT) - Refers to one or several stereotactic radiation treatments within the body, excluding the brain or spine. -

stereotactic radiosurgery - A highly precise form of radiation therapy that directs narrow beams of radiation from different angles at a brain tumor or abnormality. Using a device that keeps the head completely still, this treatment minimizes the amount of radiation to healthy brain tissue. For more information see the Stereotactic Radiosurgery page. See also stereotactic radiotherapy. -

stereotactic Radiosurgery (SRS) - Refers to a single or several stereotactic radiation treatments of the brain or spine. SRS is delivered by a team involving a radiation oncologist and a neurosurgeon. -

stereotactic radiotherapy - A form of stereotactic radiosurgery using fractionated radiation dose (smaller dose over a period of days or weeks) or hyperfractioned dose (smaller dose two to three times a day), as opposed to a single large dose, to minimize tissue damage. Also see stereotactic radiosurgery. -

sternum - The long, flat bone that forms the front of the chest cage. -

stones - See gallstones. -

stress test - A heart monitoring test to discover how well the heart works, usually performed via physical exercise, sometimes via pharmaceuticals. -

stroke - The sudden development of localized disturbances in the nervous system, usually related to reduced blood in the brain. -

subarachnoid hemorrhage - Bleeding into the subarachnoid space, or the area between the arachnoid membrane and the pia mater surrounding the brain where cerebrospinal fluid circulates.

subarachnoid space - The space between the membrane covering the spinal cord and the cord itself. -

subclavian vein - A major vein running through the shoulder region which receives blood from the large vein of the upper arm and returns it part of the way to the heart. -

subcutaneous port - A special device used in a vascular access procedure that is inserted inside a major vein for a period of months or years so that blood can be repeatedly drawn or medication and nutrients can be injected into the patient’s bloodstream on regular basis. The subcutaneous implantable port is a permanent device that consists of a catheter, a long, thin, hollow plastic tube, attached to a small reservoir, both of which are placed under the skin. -

superficial - A form of radiation where the radiation penetrates only a short distance below the surface. -

superior vena cava - One of the largest veins in the body, it returns blood from the entire upper half of the body directly to the right atrium, one of the heart chambers. -

surgeon - A medical specialist who practices surgery. -

surgery - The branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. -

surgical Oncologist - A cancer doctor who specializes in operating to cut out cancerous tumors. -

surgical shunt - A surgically created passageway to allow blood or other bodily fluids to flow between two locations. A shunt may be used to move fluid from one part of the body to another or to divert blood flow from one route to another. -

sutures - Stitches used to hold tissue together or to close a wound. -

synchrotron - A cyclic particle accelerator in which the magnetic field (to turn the particles so they circulate) and the electric field (to accelerate the particles) are synchronized with the traveling particle beam. While the cyclotron uses a constant magnetic field and a constant frequency electric field, both are varied in the synchrotron. This allows for construction of large rings that can accelerate particles to much higher energies than a cyclotron which has a limited magnet size. The synchrotron uses multiple separate bending magnets and narrow bore tubes to connect them. It can be used to produce high energy protons and other particles such as carbon ions that are used to treat cancer. In addition the energy of the particles can be varied as needed which is very difficult in a cyclotron. -

syphilis - A venereal disease that can cause lesions of the central nervous and cardiovascular systems. -

systemic Radiation Therapy - The use of radioactive isotopes that can travel throughout the body to treat certain cancers. -