Patient Resources – Speed of Light

Abscopal effect

A hypothesis in the treatment of metastatic cancer whereby shrinkage of untreated tumors occurs concurrently with shrinkage of tumors within the scope of the localized treatment.

Active Surveillance

Also known as watchful waiting or observation, it simply means that a physician and a patient are working together to monitor the status of the disease with no treatment to be undertaken immediately. Together, the doctor and patient will decide when and if treatment is necessary.

Adjuvant Therapy

A treatment that is given in addition to the primary treatment to enhance its effectiveness and reduce the chance of the tumor recurring.

Applicator

A device used to hold a radioactive source in place during brachytherapy.

Axillary lymph node dissection (ALND)

A surgery to remove lymph nodes from the underarm (armpit or axilla). Also called axillary dissection, axillary node dissection or axillary lymphadenectomy.

Beam Films

Images created by the radiation beams themselves. They are used to verify the position of the beams to confirm that treatment is accurately delivered to the right place. Also known as port films.

Biologic Therapy

Also called targeted therapy, biologic therapy works with your immune system to fight cancer. Biologic therapy is like chemotherapy. The difference is that chemotherapy attacks the cancer directly and biologic therapy helps your immune system fight the disease better.

Biopsy

A medical procedure where a sample of cells, tissues, or fluids are removed from the body for examination by a medical pathologist (a type of doctor that specializes in evaluating tissue samples). Most often, a biopsy is used to determine the presence of disease (including cancer) or other abnormalities. A biopsy can be performed by many different types of doctors, depending on where in the body the biopsy is performed.

Blocks

Pieces of metal alloy that can be used to shape the radiation beam from a linear accelerator.

Bolus

Additional material placed on the patient's skin to intentionally pull the radiation dose more superficially.

Boost

An additional dose of radiation delivered after an initial course of radiation. A boost is usually a smaller treatment in volume and is used to enhance tumor control.

Brachytherapy

A radiation therapy treatment that involves the placement of radioactive sources in or just next to a tumor or tissue. Two main forms of brachytherapy are intracavitary treatment and interstitial treatment. With intracavitary treatment, the radioactive sources are put into a space near where the tumor islocated, such as the cervix, the vagina or the windpipe. With interstitial treatment, the radioactive sources are put directly into the tissues, such as the prostate.

Cancer

Cancer develops when cells in the body begin to grow out of control. Normal cells grow, divide and die naturally. Instead of dying, cancer cells continue to grow and form new abnormal cells. Cancer cells often travel to other body parts where they grow and replace normal tissue.

Catheter

A thin, flexible hollow tube used to insert temporary radioactive sources into tumors, as in breast brachytherapy or high dose rate prostate brachytherapy.

Centigray (cGy)

Abbreviated form of centigray, a unit of radiation dose equal to 0.01 gray. Equivalent to rad, the older term for radiation dose.

Chemotherapy

Treatment with drugs to destroy cancer cells. Chemotherapy is often used alone or with surgery or radiation to treat cancer.

Clinical trial

A research study conducted to test methods of screening, prevention, diagnosis or treatment of cancer. Clinical trials try to determine if a new approach is safe and potentially effective, often comparing more commonly used treatments with a new treatment that researchers think might be better. See Phase I, II, III, IV for further details.

Computed Tomography (CT) Scan

An imaging study that uses X-rays and sophisticated computer calculations to create cross-sectional pictures of the body. These pictures can show details of the inside of the body, including bones, muscles, blood vessels, and internal organs. CT scans can be used as part of the CT simulation but also to help diagnose cancer and follow a patient after cancer treatment is complete. CT scans focus on the density of tissues, which often provides different and/or complementary information than an MRI.

Cone

A linear accelerator attachment for electron beam treatment.

Cryosurgery

Treatment performed with an instrument that freezes and destroys abnormal tissue.

CT or CAT Scan

An imaging study using X-rays and a computer to create cross-sectional pictures of the body.

CT Simulation

A specialized procedure in radiation oncology where a CT scan is performed to create a 3-D digital image of a patient’s internal anatomy. This process helps the radiation oncology team precisely map the location of the cancer and nearby structures that are sensitive to radiation. This allows the radiation oncologist to create an accurate treatment plan. While the CT scanner uses some radiation to create the images, no therapeutic radiation is delivered during this session. 

De-escalation

In cancer treatment, the reduction of exposure to treatment therapy and its negative effects. Treatment de-escalation is usually considered as a way to improve quality of life for the patient.

Distantrecurrence

Cancer that comes back but in different areas of the body.

DNA

The molecules inside cells that carry genetic information. Also known as deoxyribonucleic acid.

Dosimetrist

A member of the radiation oncology team skilled in translating the physician's radiation therapy prescription into detailed instructions for the radiation therapists treating the patient. Dosimetry work involves extensive calculations and computer modeling to arrive at the optimal treatment plan for the patient. Dosimetrists are certified by the Medical Dosimetrist Certification Board.

Electrodesiccation

The use of an electric current to destroy cancerous tissue and control bleeding.

Electrons

Subatomic particles with mass and negative charge used in radiation therapy to treat superficially located tumors due to their physics properties.

External Beam Radiation Therapy (EBRT)

Radiation therapy that uses a machine to generate a beam of high-energy radiation that travels from the machine and directed towards specific parts of the body. There are many different types of radiation therapy machines that are made from different companies that can all deliver external beam treatments.

FASTRO

Fellow of the American Society for Radiation Oncology. This designation is awarded to members of ASTRO based on service to ASTRO and contributions to the field of radiation oncology.

Gy (gray)

A measure of radiation dose by how much radiation is absorbed by the tissues.

Gynecologic Oncologist

A cancer doctor who specializes in surgically removing gynecologic cancers.

Hematologist

A physician who is specially trained in the diagnosis, treatment, and prevention of diseases of the blood and bone marrow as well as the immunologic, hemostatic (blood clotting) and vascular systems.

High Dose Rate Remote Afterloading Brachytherapy (HDR)

Brachytherapy treatment employing a very small but intense radioactive source on the end of a flexible, computer-controlled cable. By inserting this radioactive source through one or more hollow applicators placed into or near a tumor, a precisely planned amount of radiation may be delivered over a short period of time.

Hippocampus

A part of the brain structure located in the temporal lobe. This section of the brain is part of the system responsible for emotion, learning and memory.

Hodgkins Lymphoma

Also called Hodgkin's disease, this is a cancer of the lymphatic system. It most often begins in the larger, most central lymph nodes of the body -- those along the largest blood vessels of the neck, chest, abdomen, spine, and armpit and groin areas where the vessels return from the arms and legs. It is named for the British doctor Thomas Hodgkin who first described the disease in 1832.

Hormone-suppression Therapy

Slows or stops the growth of hormone-sensitive tumors by blocking the body’s ability to produce hormones or interfering with the effects of hormones on cancer cells.

Hormone Therapy

A type of cancer treatment that uses drugs to alter the body’s hormonal systems. This type of treatment is important for some types of cancers that use the body’s natural hormones, such as estrogen and testosterone, to help tumors grow. Hormonal therapy drugs interrupt these hormonal signals in various ways, resulting in damage to cancer cells.

Hyperfractionated Radiation Therapy

A type of radiation therapy in which the radiation doses are divided into smaller amounts and patients undergo treatment more than once a day.

Hypofractionated Radiation Therapy

A type of radiation therapy in which patients undergo one or just a few treatments.

Hypofractionation

Delivering the optimal amount of radiation over fewer sessions.

Image Guided Radiation Therapy (IGRT)

A radiation treatment guided by imaging equipment, such as CT, ultrasound or X-rays, taken in the treatment room just before radiation is given. During IGRT, the images are used as a final check to ensure accurate placement of the radiation treatment.

Immobilization Device

A device that is used to help a patient remain in the same position during every treatment.

Immune system

Protectsthe body against disease; identifies and attacksforeign bodiesincluding viruses, bacteria or parasites.

Immunotherapy

A treatment that uses the patient’s own immune system to help fight the cancer. Treatment will either stimulate the immune system to attack cancer cells or provide the immune system with what it needs, such as antibodies, to fight the cancer cells.

Institutional Review Board

Also known as an independent ethics committee (IEC) or ethical review board (ERB), a committee that has been formally designated to approve, monitor and review biomedical and behavioral research involving humans with the aim to protect the rights and welfare of the participants in the study.

Intensity modulated radiation therapy (IMRT)

A technique that adjusts the radiation beam to the shape of a tumor, allowing for higher, more effective doses of radiation to be delivered while minimizing exposure to surrounding healthy tissue.

Internal Radiation Therapy

A procedure in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called brachytherapy, implant radiation or interstitial radiation therapy.

Interstitial Brachytherapy

A form of seed implant where radioactive sources are placed directly into the tumor (such as the prostate).

Intracavitary Brachytherapy

A type of brachytherapy where the radioactive sources are placed into a space where the tumor is located, such as the cervix or windpipe.

Intraoperative Radiation Therapy (IORT)

Radiation therapy given during surgery. It is helpful when vital normal organs are too close to the tumor because it allows your radiation oncologist to avoid exposing those organs to radiation. This form of radiation therapy can be given as external beam therapy or as brachytherapy. It is currently being studied for breast cancer.

Inverted-Y Field Radiation

Treatment below the diaphragm to the abdomen, spleen and/or pelvis.

Involved Field Radiation

Treatment below the diaphragm to the abdomen, spleen and/or pelvis.

Irradiation

Also called radiation therapy or radiotherapy, it is the careful use of various forms of radiation to treat cancer and other diseases.

Isocenter

The single point in space where a linear accelerator's beam is aimed regardless of the orientation of the machine.

KeV

Abbreviation for thousand electron volts, a measure of radiation beam energy.

Laser Surgery

A procedure where the cancer cells are killed by laser beams.

Lasers

As used in radiation therapy, devices mounted on the walls and ceiling of the treatment room pointing to the treatment machine's isocenter to allow accurate positioning of the patient from day to day.

Linear Accelerator or Linac

The most common type of machine used to deliver external radiation therapy.

Low-Dose-Rate Brachytherapy

Brachytherapy in which sources are left in place for the duration of treatment. This includes temporary LDR in which patients are hospitalized for several days of temporary brachytherapy. It also includes permanent LDR in which seeds are permanently placed.

Lumpectomy

A surgery in which only the tumor and some surrounding tissue is removed from the breast. It is also known as breast-conserving surgery.

Lymph nodes

Small glands that filter a clear fluid called lymph through the lymphatic system.

Lymphatic system

Part of the immune system, the lymphatic system is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials. The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body.

Lymphedema

A long-term condition where excess fluid (lymph) collects in tissues causing swelling.

Lymphoma

A tumor found in the lymphatic system. The two main types of lymphomas are Hodgkin’s and non-Hodgkin’s lymphomas.

Malignant

A cancerous growth with a tendency to invade and destroy nearby tissue and spread to other parts of the body.

Mantle Field Radiation

Radiation therapy to the parts of the body above the diaphragm to the neck, chest and/or underarm areas.

Mask

An immobilization device fitting over a patient's head and face to allow accurate repositioning from day to day.

Mastectomy

Breast cancer surgery that removes the entire breast.

Medical Oncologist

A cancer doctor who specializes in giving drugs (called chemotherapy or targeted agents) to kill cancer cells or slow down their growth. Some medical oncologists are also hematologists, meaning they have experience treating blood disorders.

Melanocytes

Cells located in the epidermis responsible for the production of melanin. The can suffer malignant transformation giving rise to a tumor known as malignant melanoma.

Metastases (Metastasis)

The spread of cancer from one part of the body to another.

Mohs Surgery

Also known as chemosurgery, created by a general surgeon, Dr. Frederic E. Mohs, microscopically controlled surgery that is highly effective for common types of skin cancer and squamous cell carcinoma.

Monoclonal Antibodies

Monoclonal antibodies target certain cells in the body by attaching themselves to those molecules. This causes some cancer cells to die and makes other cells more likely to be killed by radiation and chemotherapy.

MR or MRI Scan

An imaging study using a magnetic field, radiowaves, and sophisticated computer calculations to create cross-sectional pictures of the body. Similar to a CT scan, an MRI scan can show the internal anatomy of the body. MRI scans focus on the density of hydrogen atoms, which often provides different and/or complementary information than a CT scan.

Multileaf Collimator (MLC)

Located in the head of the linear accelerator, it is used to shape the radiation beam.

MV or MeV

Abbreviation for million electron volts, a measure of radiation beam energy.

Neuroblastoma

A cancerous tumor that begins in nerve tissue of infants and very young children, often younger than five years of age.

Neurosurgeon

A physician trained in surgery of the nervous system and who specializes in surgery on the brain and other parts of the nervous system. Sometimes called a brain surgeon.

Neutron Beam Therapy

A specialized type of external beam radiation therapy using neutrons to treat tumors.

Non-Hodgkin's Lymphoma

Also called NHL, it is a cancerous growth of the cells that make up the lymph nodes. It is eight times more common than Hodgkin's lymphoma.

Oligometastatic

A type of metastasis in which cancer cells from the original tumor travel through the body and form a small number of new tumors in one or two other parts of the body.

Oncologist

A doctor who specializes in treating cancer. Some oncologists specialize in a particular type of cancer treatment. For example, a radiation oncologist specializes in treating cancer with radiation.

Organ at Risk (OAR)

A healthy organ or tissue located near a tumor (cancer) that could be damaged by radiation therapy. These organs are outlined during the process of creating a radiation plan. The radiation oncologist ensures these areas are protected against significant injury.

Organ Preservation

The principle that using radiation therapy and chemotherapy achieves the same local control and survival that aggressive surgery in the definitive treatment of some malignancies without the need to sacrifice the organ and the function. It is widely used in larynx, head and neck in general, esophageal, anal canal and other organs.

Overall Survival (OS)

The length of time from either the date of diagnosis or the start of treatment that patients diagnosed with the disease are still alive. In a clinical trial, measuring the overall survival is one way to see how well a new treatment works.

Palliative

A type of care, also known as supportive care. The goal of this care is to improve the quality of life of cancer patients by relieving distressing symptoms such as pain, shortness of breath, loss of appetite, problemssleeping, fatigue and many more. Many cancer patients undergo palliative care while maintaining their other cancer treatments.

Palliative Care or Palliation

Also known as supportive care, palliative care strives to improve the quality of life of people with serious illnesses, including cancer. 

Partial Breast Irradiation After Lumpectomy (PBI)

Partial Breast Irradiation After Lumpectomy is a treatment strategy where selected patients can receive radiation treatment to only the part of the breast (the part of the breast that had the tumor) instead of the whole breast) over a shorter period of time.

Patient Navigator

A patient navigator is a social worker, nurse or other knowledgeable individual who can assist you in finding your way within the complex health care system. Patient navigators know who to call and where to go so your care can be most efficiently provided.

Perometry

A non-invasive technique that usesinfrared light to measure limb circumference and volume of fluid and is more accurate than a simple limb circumference measurement. The measurement tool is called a perometer.

PET Scan

A positron emission tomography (PET) scan is an imaging study using a very small dose of a radioactive tracer attached to a sugar molecule and injected into the patient. These sugar molecules are taken up by areas of the body that are very active, including cancer tissues. The scanner is able to detect where the radioactive sugar molecules are in the body, which is used to create an image of the body showing areas of cancer activity.

Phase I, II, III, IV

Clinical trials are broken down into four phases of study.

Phase I often looks at combining radiation therapy with other treatments such as surgery or drugs to evaluate new ways to deliver radiation therapy.
Phase II tries to establish if the new treatment determined in Phase I is effective in controlling the tumor
Phase III compares the new treatment against the current standard treatment. Patients are randomly assigned to one of two groups; one group receives the standard treatment, the other receives the new treatment and results are compared. If the new treatment results are better than standard treatment, researchers will reconsider the standard of care treatment.
Phase IV is the final step in the process and tests to make sure the new treatment is safe and effective over a long period of time

Photodynamic Therapy

A treatment for cancer involving three key components: a photosensitizer, light, and tissue oxygen.

Photons

Radiation therapy particle, composed exclusively of energy, with no mass or charge, that is used in radiation therapy. They can be produced in the nucleus of the atom (Gamma Radiation) or in the superficial shell (X-rays). In general, they penetrated in depth and they are used to treat deeply seated tumors.

Primary Care Physician (PCP)

A medical doctor that provides definitive care for patients as a first point of contact with the medical system. Additionally, they provide ongoing and comprehensive care for health needs, including new (acute), long-standing (chronic), and preventative care needs. When patients are seen by specialists, PCPs also help to coordinate the care received by the patient.

Primary Tumor

A tumor that is at the original site where it first arose.

Progression Free survival (PFS)

The length of time during and after treatment that a patient lives with cancer, but the cancer does not get worse. In a clinical trial, measuring the progression-free survival is one way to see how well a new treatment works.

Proton Beam Radiation Therapy (also called Proton Therapy)

A type of external beam radiation therapy that uses protons (tiny particles with a positive charge) to damage tumor cells. In certain situations, proton therapy can improve outcomes by reducing the amount of radiation received by nearby healthy tissues. This is accomplished as a result of how protons travel differently through the body.

Protons

Radiation therapy particle, with mass and a positive charge that has a very particular penetration properties called in general Bragg Peak. Because of that, it can be used to treat deep tumors or tumors close to very critical structures, with minimal irradiation of those otherwise organs at risk.

Quality Assurance (QA) Programs

The policies and procedures radiation therapy centers follow to make sure the treatment team works together to make the treatments as safe as possible. QA programs are usually created by the medical physicist. An important part of the QA program is taking precise measurements of the radiation beam and performing other safety tests on a regular basis. Patients and caregivers are encouraged to ask about the QA program at the center where they are receiving radiation treatment.

Radiation Oncologist

A doctor who specializes in treating cancer and other diseases with radiation therapies. The radiation oncologist leads the radiation therapy treatment team.

Radiation Oncology Nurse

A member of the radiation oncology treatment team, the radiation oncology nurse works together with the radiation oncologist and radiation therapists to care for you and your family during your radiation treatments.

Radiation Physicist

A person who makes sure that the radiation machine or implant delivers the right amount of radiation to the correct site in the body. The physicist works with the radiation oncologist to choose the treatment schedule and dose that has the best chance of killing the most cancer cells.

Radiation Therapist

A health professional who gives radiation treatment.

Radiation Therapy

Also called radiotherapy or irradiation, it is the careful use of various forms of radiation to treat cancer and other diseases.

Radioimmunotherapy

The use of radiolabeled antibodies to deliver radiation directly to a tumor.

Radiolabeled Antibodies

Monoclonal antibodies that have had a radioactive isotope attached to them in a process called radiolabeling. These antibodies are designed to attach themselves directly to diseased cells and damage them with small amounts of radiation without hurting nearby healthy cells.

Radiologist

A medical doctor who specializes in diagnosing and treating diseases using medical imaging techniques like X-rays, CT scans, MRIs and ultrasounds. When your cancer care team orders a scan, a radiologist reviews the scan and provides a report of the findings to your doctors so they can make better decisions about your medical care.

Radiopharmaceutical Therapy (RPT)

A treatment that uses injected or ingested radioactive material to target and treat certail types of cancer. Also called theranostics or radiogland therapy.

Radioprotector

A type of drug that protects normal tissues in the area being treated.

Radioresistant

A term used to describe a tumor that does not respond well to radiation therapy.

Radiosensitizer

A type of drug that can make a tumor respond better to radiation therapy.

Radiosurgery

A technique that allows your radiation oncologist to precisely focus beams of radiation to destroy certain types of tumors. It is most often called stereotactic radiotherapy.

Radiotherapy

Also called radiation therapy or irradiation, it is the careful use of various forms of radiation to treat cancer and other diseases.

Randomized study

A study in which the participants (patients) are divided at random into separate groups to compare different treatments.

Regional lymph node radiation (RLNR)

Radiation treatment to nearby lymph nodes, which is commonly used after mastectomy in women with node-positive breast cancer. Also termed regional nodal irradiation (see below).

Regional nodal irradiation (RNI)

Radiation treatment to nearby lymph nodes, which is commonly used after mastectomy in women with node-positive breast cancer. Also termed regional lymph node radiation (see above).

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.

Seeds

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

Sentinel lymph node biopsy (SLNB)

A biopsy that does minimal sampling of lymph nodes most likely to be involved with cancer.

Side Effects

An effect of a drug or other type of treatment that is not planned but occurs in addition to or beyond its desired effect. Typically, when determining whether a treatment should be used, the benefit of the treatment is thought to outweigh the risks, including the side effects.

Simulation (radiation simulation)

In cancer treatment, a process used to plan radiation therapy so that the target area is precisely located and marked.

Simulation

The process of planning radiation therapy to allow the radiation to be delivered to the intended location.

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 1, 2, 3 cancers

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

Stent

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

Stereotactic ablative radiotherapy (SABR)

A treatment that delivers one to five stereotactic radiation treatments to tumors within the body, excluding brain orspine. Also known as stereotactic body radiation therapy (SBRT).

Stereotactic body radiation therapy (SBRT)

A type of external radiation therapy that uses special equipment to position a patient and precisely deliver radiation to tumorsin the body. The total dose of radiation is divided into smaller doses given over several days. Also called SABR, (see above).

Stereotactic radiosurgery (SRS)

A treatment that delivers one to five stereotactic radiation treatments to the brain or spine. This treatment does not involved surgery, an incision is not made, and tissue is not surgically removed.

Stereotactic Radiotherapy

A technique that allows your radiation oncologist to precisely focus beams of radiation to destroy certain types of tumors. It is sometimes called radiosurgery.

Superficial

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

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.

Systemic Radiation Therapy

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

Targeted Therapy

A type of cancer treatment that targets proteins that control how cancer cells grow, divide, and spread. These treatments are often given intravenously (through the veins) under the guidance of a medical oncologist. These treatments often target proteins that are mainly present within cancer cells, leading to more specific treatments with less side effects. These treatments are not available for every type of cancer.

Three Dimensional Conformal Partial Breast Irradiation

A type of external beam radiation therapy where only part of the breast receives external beam radiation.

Three-Dimensional Conformal Radiotherapy (3-D CRT)

This type of external beam radiation therapy combines multiple radiation treatment fields to deliver precise doses of radiation to the affected area. Tailoring each of the radiation beams to focus on the tumor delivers a high dose of radiation to the tumor and avoids nearby healthy tissue.

Total Body Irradiation

Delivering radiation to the entire body. In the case of lymphoma, it is often done before chemotherapy and a stem cell or bone marrow transplant.

Total Nodal Irradiation

Delivering radiation to all the lymph nodes in the body.

Toxicity

The degree to which something is harmful to a patient.

Treatment Plan

A radiation oncologist’s prescription describing how a patient should be treated with radiation therapy. The radiation oncology team uses special software to maximize radiation to the tumor while sparing healthy tissue and organs.

Tumor

An abnormal lump or mass of tissue.

Tumor Board

A tumor board is a group of specialists that meets regularly as a team to discuss individual cancer cases and provide multiple expert opinions. They contribute their knowledge and perspective to create and coordinate a tailored treatment plan that gives the best outcome for an individual patient.

Urologist

A surgeon who specializes in the genital and urinary systems.

Watchful Waiting

Also known as active surveillance or observation, it is the least invasive treatment strategy that simply means that a physician and a patient are working together to actively observe the progression of the cancer or tumor.

Wedge

A metal filter of triangular cross-section placed within a radiation beam to intentionally feather the radiation intensity from one side of the beam to the other.

X-rays

A type of high-energy radiation. In low doses, X-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, X-rays are used to treat cancer.

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