Radiation Therapy: A Complete Patient and Family Guide

At a glance: Radiation therapy—also called radiotherapy—uses carefully measured high-energy radiation to damage cancer-cell DNA, destroy cancer cells, or prevent them from continuing to grow. It may be used alone or with surgery, chemotherapy, immunotherapy, targeted therapy, hormone therapy, or stem-cell transplantation.

Important: Radiation therapy is not one treatment or one standard experience. The radiation type, dose, schedule, treatment area, expected benefit, and possible side effects are individually planned according to the cancer, treatment goal, previous therapy, and patient’s health.

Personalized-care reminder: Never assume that a radiation schedule used for another person—or for another cancer—is appropriate for you. Radiation doses are carefully calculated for a particular tumor and nearby organs. Treatment should be directed by a qualified radiation-oncology team.

Quick Jump: Radiation Therapy Topics

• What Is Radiation Therapy?
• How Radiation Works
• Goals of Radiation Therapy
• Who May Benefit?
• When Radiation May Not Be Recommended
• The Radiation-Oncology Team
• Main Types of Radiation Therapy
• External-Beam Radiation
• Modern External-Beam Techniques
• Brachytherapy
• Systemic Radiopharmaceutical Therapy
• Dose, Fractions and Schedules
• Simulation and Treatment Planning
• Masks, Molds, Marks and Preparation
• What Happens During Treatment?
• Monitoring and Treatment Reviews
• How Doctors Know It Is Working
• Common Side Effects
• Side Effects by Treatment Area
• Skin and Hair Care
• Fatigue and Daily Function
• Urgent Warning Signs
• Will I Be Radioactive?
• Pregnancy, Fertility and Sexual Health
• Pacemakers and Implanted Devices
• Radiation with Other Treatments
• Previous Radiation and Re-Irradiation
• Long-Term and Late Effects
• Nutrition and Physical Activity
• Supportive and Integrative Care
• Questions to Ask the Care Team
• Radiation Myths and Facts
• Clinical Trials and New Directions
• Costs and Financial Planning
• Treatment Checklist
• Trusted Resources

Radiation therapy is a cancer treatment that uses high-energy rays or particles to damage cancer cells. Depending on the treatment, radiation may come from:

• A machine outside the body
• A radioactive source placed inside or near a tumor
• A radioactive medicine swallowed or injected into the bloodstream

Most external-beam radiation and brachytherapy are considered local treatments because they treat a defined body area. Systemic radiopharmaceutical therapy travels through the bloodstream and targets cells or tissues with particular biological characteristics.

Radiation therapy is used in the treatment of many cancers, including cancers of the brain, breast, cervix, head and neck, lung, prostate, rectum, skin, uterus, bladder, thyroid, blood and lymphatic system, bone, soft tissues, and other organs.

Learn more from the National Cancer Institute’s radiation-therapy overview.

Important distinction: Radiation therapy used to treat cancer is different from diagnostic imaging such as ordinary x-rays, mammograms, and CT scans. Treatment radiation generally uses substantially higher, carefully calculated doses directed at a defined target.

Radiation damages DNA inside cells. Cancer cells with enough DNA damage may stop dividing or die. The body then breaks down and removes damaged cells over time.

Radiation does not always destroy cancer cells immediately. Its biological effects can continue after a treatment session, and tumor shrinkage may occur gradually over days, weeks, or months.

Healthy cells near the treatment area may also receive some radiation. Modern planning techniques are designed to:

• Concentrate the prescribed dose in the tumor
• Reduce radiation exposure to nearby healthy organs
• Account for tumor shape, depth, and movement
• Allow healthy tissues time to repair between treatments
• Remain within established dose limits for sensitive structures

The balance between tumor control and protection of normal tissue is one of the central principles of radiation oncology.

1. Curative or Definitive Radiation

Radiation may be used as the main treatment with the goal of eliminating the cancer or producing long-term control. It may be given alone or with chemotherapy, immunotherapy, hormone therapy, or another treatment.

2. Neoadjuvant Radiation

Radiation is given before surgery to shrink a tumor, improve the possibility of complete removal, reduce recurrence risk, or make organ-preserving surgery more feasible. Chemotherapy may be given at the same time for selected cancers.

3. Adjuvant Radiation

Radiation is given after surgery to destroy cancer cells that may remain in the surgical area or nearby lymph nodes and reduce the risk of local or regional recurrence.

4. Chemoradiation

Chemotherapy is given during radiation therapy. Certain medicines make cancer cells more sensitive to radiation. The combination can improve cancer control in selected diseases but may also increase side effects.

5. Intraoperative Radiation Therapy

Radiation is delivered during surgery directly to an exposed tumor bed or high-risk area. Nearby organs may be moved or shielded when appropriate. This approach is available only for selected cancers and situations.

6. Consolidation Radiation

Radiation may be given after chemotherapy or another systemic treatment to strengthen the response in an original tumor site, involved lymph nodes, or another high-risk area.

7. Prophylactic or Preventive Radiation

In selected cancers, radiation may be directed at an area where microscopic cancer is considered especially likely to develop, even when visible disease has not been detected there.

8. Ablative Radiation

Highly focused radiation may deliver a strong biological dose to a small tumor or limited number of tumors. It may be used as a curative local treatment or to control selected metastatic sites.

9. Palliative Radiation

Palliative radiation is used to reduce pain, bleeding, pressure, airway narrowing, spinal-cord compression, brain symptoms, obstruction, or other cancer-related problems. Treatment may consist of one session or a short course, depending on the situation.

Radiation therapy may be considered when one or more of the following apply:

• The cancer is localized or concentrated in a defined region.
• Radiation offers a possibility of cure or long-term local control.
• Microscopic cancer may remain after surgery.
• A tumor needs to shrink before surgery.
• The cancer involves lymph nodes that require local treatment.
• Surgery would cause unacceptable loss of function or is not medically possible.
• Radiation can preserve an organ or avoid a more extensive operation.
• A small tumor or limited number of metastatic tumors can be targeted precisely.
• Cancer is causing pain, bleeding, pressure, obstruction, or neurologic symptoms.
• A radioactive medicine can target a biological feature of the cancer.

Radiation may not be the preferred treatment when:

• The cancer is unlikely to respond adequately to radiation.
• Surgery, chemotherapy, immunotherapy, targeted therapy, hormone therapy, or surveillance is expected to provide greater benefit.
• The target cannot be treated safely without exposing a critical organ to unacceptable risk.
• The area has previously received radiation near its safe tissue tolerance.
• The patient cannot safely maintain the required treatment position.
• Serious medical instability or infection must be addressed first.
• Pregnancy creates unacceptable fetal risk for the proposed treatment.
• The expected benefit is very small compared with the likely burden or harm.
• The patient decides that the treatment does not match their goals or preferences.

A recommendation against one radiation technique does not mean that every form of cancer treatment has been ruled out. A different radiation method, systemic treatment, surgery, clinical trial, or symptom-focused plan may be appropriate.

Radiation Oncologist

A physician who evaluates the patient, recommends radiation when appropriate, prescribes the dose and treatment area, approves the treatment plan, manages side effects, and coordinates radiation with other cancer treatments.

Radiation Therapist

A specially trained professional who positions the patient, operates the radiation-delivery equipment, performs treatment imaging, and carries out the approved treatment plan.

Medical Physicist

A specialist who helps ensure that radiation equipment is calibrated, dose calculations are accurate, treatment plans are technically sound, and safety and quality-assurance procedures are followed.

Medical Dosimetrist

A professional who works with the radiation oncologist and physicist to design a treatment plan that delivers the prescribed dose to the target while limiting exposure to nearby organs.

Radiation-Oncology Nurse

A nurse who provides education, symptom assessment, skin and nutrition guidance, medication support, and coordination during treatment.

Other Team Members

Depending on the treatment, the team may include surgeons, medical oncologists, nuclear-medicine physicians, radiologists, pathologists, anesthesiologists, dietitians, dentists, speech therapists, rehabilitation professionals, social workers, psychologists, fertility specialists, and palliative-care clinicians.

1. External-Beam Radiation Therapy

Radiation is generated by a machine outside the body and directed toward the cancer. External-beam radiation is the most commonly used form of radiation therapy.

2. Internal Radiation Therapy or Brachytherapy

A sealed radioactive source is placed inside the body, within or near the tumor. It may remain temporarily or permanently, depending on the treatment.

3. Systemic Radiation Therapy

A radioactive medicine is swallowed or injected. It travels through the bloodstream and is taken up by particular tissues or targeted cancer cells.

External-beam radiation comes from a machine—most commonly a linear accelerator—that aims radiation at the treatment area. The machine may rotate around the patient and deliver radiation from several angles.

The radiation beams are invisible. Patients generally do not feel the radiation entering the body. The machine may make clicking, humming, or whirring sounds, but it does not normally touch the patient.

External-beam treatments may use:

• Photons: High-energy x-rays that can reach tumors deep inside the body
• Electrons: Particles used mainly for tumors on or near the body surface
• Protons: Charged particles that can reduce radiation deposited beyond the target in selected situations

The best beam type depends on the tumor’s depth, shape, location, nearby organs, available evidence, and patient factors. Proton therapy is not automatically better than photon therapy for every cancer.

National Cancer Institute: External-Beam Radiation Therapy

Three-Dimensional Conformal Radiation Therapy

Three-dimensional conformal radiation therapy, or 3D-CRT, uses CT and other imaging to define the tumor and shape several radiation beams around it.

Intensity-Modulated Radiation Therapy

Intensity-modulated radiation therapy, or IMRT, divides radiation into many smaller beam segments. The intensity can vary across each beam, allowing the treatment to conform closely to complex targets while reducing dose to selected normal structures.

Volumetric-Modulated Arc Therapy

Volumetric-modulated arc therapy, or VMAT, is a form of modulated radiation delivered while the machine rotates around the patient. It can deliver complex dose patterns efficiently.

Image-Guided Radiation Therapy

Image-guided radiation therapy, or IGRT, uses imaging before or during treatment to verify the tumor and patient position. Adjustments may be made before radiation is delivered.

Stereotactic Radiosurgery

Stereotactic radiosurgery, or SRS, delivers highly focused radiation to a small target in the brain or central nervous system, usually in one or a few treatments. Despite its name, it does not involve an incision.

Stereotactic Body Radiation Therapy

Stereotactic body radiation therapy, also called SBRT or SABR, delivers highly focused radiation to selected tumors outside the brain in a small number of treatments. Careful motion management and image guidance are often required.

Proton-Beam Therapy

Proton therapy can limit radiation deposited beyond the tumor. It may offer meaningful normal-tissue protection for selected pediatric cancers, tumors near highly sensitive structures, and other carefully chosen cases. Comparative benefit depends on the individual treatment plan.

Electron-Beam Therapy

Electron beams do not travel deeply through tissue and are commonly used for selected skin tumors, scars, lymph nodes, or other superficial targets.

Total-Body Irradiation

Total-body irradiation delivers radiation to the entire body, usually as part of preparation for selected stem-cell or bone-marrow transplants.

Total-Skin Electron Therapy

Total-skin electron therapy treats much of the skin surface and may be used for selected widespread skin lymphomas.

Intraoperative Radiation Therapy

Intraoperative radiation is delivered during surgery to a visible tumor bed or high-risk area. It may be used as the full local treatment or as a boost combined with external-beam therapy.

Technology is not the treatment goal: A newer or more complex machine is not automatically safer or more effective. The appropriate technique is the one that meets the cancer-treatment objective while protecting normal tissue and following evidence-based quality standards.

Brachytherapy places a sealed radioactive source inside the body, within or close to the tumor. Because the source is close to the cancer, a high dose can be delivered to a limited area while radiation decreases rapidly farther away.

Brachytherapy may be used for selected cancers of the:

• Prostate
• Cervix
• Uterus or vagina
• Breast
• Head and neck
• Eye
• Skin
• Other carefully selected locations

Interstitial Brachytherapy

The radioactive source or applicator is placed directly into tissue within or near the tumor. Prostate implants are one example.

Intracavity Brachytherapy

An applicator is placed inside a body cavity, such as the vagina or uterus, to treat nearby tissues.

Surface or Plaque Brachytherapy

A radioactive applicator is positioned on or near a surface. An eye plaque used for selected ocular tumors is an example.

High-Dose-Rate Brachytherapy

A high-activity source is temporarily placed through an applicator or catheter for a short period, often minutes. The source is then removed. Several sessions may be required.

Low-Dose-Rate Brachytherapy

The source remains in place for a longer period, sometimes one or more days. Hospital precautions may be required while the active source is present.

Permanent Implants

Small radioactive seeds may remain permanently in the body. Their radiation becomes weaker over time. Temporary distance or visitor precautions may be recommended, especially around pregnant people and young children.

Placement may require local anesthesia, sedation, regional anesthesia, or general anesthesia. Imaging may be used to guide applicators and verify source position.

National Cancer Institute: Brachytherapy to Treat Cancer

Systemic radiation therapy uses a radioactive substance that is swallowed or given through a vein. The substance circulates in the body and is taken up by particular tissues or targeted cancer cells.

Examples include:

• Radioactive iodine: Used for selected thyroid cancers
• Targeted radionuclide therapy: Used for selected neuroendocrine tumors and advanced prostate cancers
• Bone-targeting radiopharmaceuticals: Used in selected cancers involving bone
• Radioimmunotherapy: A radioactive substance linked to an antibody that targets selected cancer cells
• Radioembolization: Radioactive microspheres delivered through arteries supplying selected liver tumors

Eligibility may depend on imaging that confirms the target is present, kidney and bone-marrow function, previous treatment, extent of disease, pregnancy status, and other medical factors.

After systemic radioactive treatment, urine, saliva, sweat, stool, blood, or other body fluids may contain radiation for a period. Patients receive written precautions explaining bathroom use, laundry, hydration, sleeping arrangements, contact with children or pregnant people, travel, and handling of bodily waste.

Follow the exact precautions provided for the specific radioactive medicine. Safety instructions and their duration differ substantially among treatments.

What Is a Gray?

The absorbed radiation dose is measured in a unit called the gray, abbreviated Gy. A centigray, abbreviated cGy, is one-hundredth of a gray. Treatment records may use either unit.

What Is a Fraction?

A fraction is one radiation-treatment session. The total prescribed dose may be divided into several fractions to protect healthy tissue and take advantage of biological differences between cancer cells and normal cells.

Conventional Fractionation

A moderate dose is delivered once daily, commonly five days per week, over several weeks. The schedule depends on the cancer and treatment purpose.

Hypofractionation

A larger dose is given in each session, reducing the total number of treatment visits. Hypofractionated schedules are well established for several cancers but are not suitable for every tumor or nearby organ.

Ultra-Hypofractionation or Stereotactic Treatment

Very precise, high-dose treatment is delivered in a small number of sessions, often one to five, for carefully selected targets.

Hyperfractionation

A smaller dose is given more than once per day, with a required interval between sessions. This schedule may be used for selected cancers.

Palliative Schedules

Symptom-relieving radiation may be delivered in one session or a short series of treatments, depending on the location, expected benefit, previous radiation, and patient needs.

Do not compare total dose numbers across different cancers without expert interpretation. Biological effect depends on the dose per fraction, total dose, tissue type, treatment technique, and other therapies.

Simulation is a planning session used to reproduce the position in which treatment will be delivered. It is not usually the first radiation-treatment session.

During simulation, the team may:

• Review the treatment plan and consent
• Place the patient in a specific treatment position
• Create a mask, cradle, mold, cushion, or other immobilization device
• Perform a planning CT scan
• Use contrast material when appropriate
• Combine CT images with MRI or PET images
• Place temporary marks or small permanent tattoos on the skin
• Record breathing or internal-organ movement
• Provide bladder-filling or bowel-preparation instructions
• Establish a baseline for treatment-position verification

After simulation, the radiation oncologist identifies:

• The visible tumor or known disease area
• Areas at risk for microscopic cancer
• A margin that accounts for movement and positioning
• Nearby organs that should be protected

The dosimetrist and medical physicist help create and verify the plan. The team evaluates how much radiation reaches the target and nearby structures before treatment begins.

Planning may take several days or longer because the treatment must be individualized and pass technical and safety reviews.

Immobilization Devices

Masks, molds, cushions, cradles, vacuum bags, bite blocks, or body frames help the patient remain in a reproducible position. They are positioning tools and are not meant as restraints.

Skin Marks and Tattoos

Small marks may help align the body with the treatment equipment. Some are temporary ink marks; others are tiny permanent tattoos. Do not scrub off temporary marks unless the team says they are no longer needed.

Bladder and Bowel Preparation

Pelvic or abdominal treatments may require a comfortably full bladder, an empty bladder, bowel preparation, dietary changes, or consistent timing. Reproducing internal-organ position can improve treatment accuracy.

Breathing and Motion Management

The team may use breath-hold, respiratory gating, abdominal compression, motion tracking, or repeated imaging when breathing moves the tumor or nearby organs.

Dental Evaluation

Before radiation to the head or neck, a dental assessment may be needed. Dental infection, extractions, fluoride care, dry-mouth prevention, and long-term jawbone protection should be addressed before treatment whenever possible.

Medicines and Supplements

Provide a complete list of prescription medicines, nonprescription products, vitamins, herbs, supplements, cannabis products, and other substances. Do not apply unapproved creams, oils, herbal mixtures, or topical products to the treatment area.

Identity and Treatment Verification

The team confirms the patient’s identity, treatment area, prescription, and setup. Multiple safety checks are built into the radiation-delivery process.

Positioning

The radiation therapist positions the patient using the same devices and reference marks established during simulation.

Imaging

X-ray, CT, surface imaging, MRI, or another image-guidance method may be used to verify alignment. Small adjustments can be made before treatment.

Radiation Delivery

The therapists leave the room during beam delivery but continuously observe and communicate with the patient through cameras and an intercom. The patient must remain still but can breathe normally unless instructed otherwise.

The machine may rotate around the treatment table. It may stop at several angles or move continuously. The radiation itself is usually delivered for only part of the total appointment time.

Communication During Treatment

Tell the therapist about pain, coughing, panic, nausea, breathing difficulty, or the need to move. The machine can be stopped when necessary.

After the Session

Most patients receiving external-beam radiation leave the treatment center shortly afterward. Sedation, anesthesia, combined chemotherapy, or serious illness may require additional monitoring or transportation assistance.

Patients commonly meet with the radiation oncologist, nurse, or another clinician at regular intervals during the treatment course. These visits may be called on-treatment visits or weekly treatment reviews.

The team may assess:

• Skin changes
• Fatigue
• Pain
• Eating, drinking, weight, and hydration
• Swallowing or mouth symptoms
• Bowel and bladder changes
• Breathing or neurologic symptoms
• Medication needs
• Emotional well-being
• Ability to continue treatment safely

Blood tests may be required when a large body area, bone marrow, blood cancer, or combined chemotherapy is involved.

Repeat imaging may show that the tumor or body shape has changed. In selected cases, the treatment plan may be adjusted through a process known as adaptive radiation therapy.

Report side effects between scheduled visits. Do not wait for the next weekly review when symptoms are severe, rapidly worsening, or interfering with eating, drinking, breathing, movement, or medication use.

Treatment response may be assessed through:

• Changes in symptoms
• Physical examinations
• Blood tests or tumor markers
• CT, MRI, PET, ultrasound, or other imaging
• Endoscopy or other procedures
• Pathology after surgery
• Long-term surveillance

Imaging is not always performed immediately after radiation. Radiation-related inflammation can temporarily make an area look enlarged or active. The appropriate timing depends on the cancer and treatment.

Side effects do not prove whether treatment is working. Severe skin changes, fatigue, or other effects do not mean the tumor is responding better, and having few side effects does not mean radiation has failed.

Radiation side effects depend mainly on:

• The body area treated
• The organs included in or near the radiation field
• The total dose and dose per fraction
• The number and timing of treatments
• Previous radiation or surgery
• Chemotherapy or other treatment given at the same time
• Age, health, nutrition, smoking, and individual sensitivity

Frequently reported effects include:

• Fatigue
• Skin irritation in the treated area
• Hair loss limited mainly to the treatment area
• Swelling or tenderness
• Appetite or weight changes
• Area-specific bowel, bladder, swallowing, breathing, or neurologic effects
• Temporary inflammation of tissues receiving radiation

Brain and Head

• Fatigue
• Hair loss in the treated area
• Scalp changes
• Headache
• Nausea or vomiting
• Temporary swelling
• Memory, concentration, vision, hormone, or neurologic changes depending on the area treated

Head and Neck

• Mouth sores
• Dry mouth or thick saliva
• Taste changes
• Difficulty chewing or swallowing
• Skin irritation
• Weight loss or dehydration
• Dental problems
• Hoarseness
• Reduced thyroid function later
• Jaw stiffness or tissue tightening

Breast and Chest Wall

• Skin redness, darkening, dryness, itching, or peeling
• Breast or chest-wall tenderness
• Swelling
• Fatigue
• Temporary hair loss in the treated area
• Later tissue firmness or breast-size changes
• Rare heart or lung effects, depending on the area treated

Lung and Chest

• Fatigue
• Cough
• Shortness of breath
• Chest discomfort
• Difficulty or pain with swallowing
• Skin changes
• Radiation-related lung inflammation that may occur after treatment

Upper Abdomen

• Nausea or vomiting
• Loss of appetite
• Fatigue
• Diarrhea
• Abdominal discomfort
• Skin changes
• Organ-specific effects involving the liver, kidneys, stomach, or bowel

Pelvis, Prostate, Rectum and Gynecologic Areas

• Diarrhea, urgency, cramping, or rectal irritation
• Frequent, urgent, or uncomfortable urination
• Fatigue
• Pelvic skin irritation
• Menstrual or hormonal changes
• Fertility changes
• Vaginal dryness, narrowing, or discomfort
• Erection or ejaculation changes
• Later bowel, bladder, bone, or sexual effects

Bone and Soft Tissue

• Temporary pain flare
• Skin irritation
• Fatigue
• Swelling
• Muscle or joint stiffness
• Later weakening of bone or soft-tissue changes in selected cases

Bone Marrow or Large Treatment Areas

• Low white blood cells
• Anemia
• Low platelets
• Increased infection or bleeding risk
• Greater fatigue

Area-specific care matters: A person receiving radiation to the breast will not have the same expected effects as a person receiving radiation to the brain, throat, lung, abdomen, or pelvis. Ask for a written list specific to your treatment field.

Skin in the treatment area may become dry, red, darker, itchy, tender, swollen, or sensitive. In some cases it may peel or become moist and painful. Changes commonly build gradually during treatment and may continue to worsen briefly after the final session before improving.

General skin-care principles include:

• Wash gently with lukewarm water and mild products approved by the team.
• Pat the area dry rather than rubbing.
• Use only creams, moisturizers, deodorants, dressings, or topical medicines approved for the treatment area.
• Avoid heating pads, ice packs, hot-water bottles, and extreme temperatures.
• Avoid tight clothing, friction, and scratching.
• Protect the area from sunlight.
• Do not place adhesive tape over fragile treated skin unless instructed.
• Do not scrub off treatment marks.
• Report blistering, open skin, drainage, increasing pain, or signs of infection.

Hair loss generally occurs only where radiation enters or exits the body. Hair may regrow after treatment, but regrowth can be thinner or absent after higher doses.

Ask when products may be applied before treatment. Instructions differ among centers and treatment areas.

Fatigue is one of the most common effects of radiation therapy. It may increase gradually as treatment continues and can persist for weeks or longer afterward.

Fatigue may also be influenced by:

• The cancer itself
• Daily travel for treatment
• Poor sleep
• Pain
• Anemia
• Reduced food or fluid intake
• Chemotherapy or other medicines
• Stress, anxiety, or depression
• Infection or another medical problem

Helpful strategies may include:

• Prioritizing essential activities
• Accepting help with transportation, meals, children, or household tasks
• Using brief planned rest periods
• Maintaining a regular sleep schedule
• Participating in safe, appropriately paced physical activity
• Addressing pain, nausea, nutrition, mood, and sleep problems
• Requesting work or school accommodations

Do not drive when affected by severe fatigue, dizziness, sedating medicines, vision changes, weakness, confusion, or another condition that makes driving unsafe.

Follow the emergency instructions provided by your own oncology team. Contact the team promptly for:

• New or rapidly worsening trouble breathing
• Chest pain
• Severe headache, confusion, fainting, seizure, or new weakness
• Loss of bowel or bladder control
• New severe back pain with weakness, numbness, or difficulty walking
• Persistent vomiting or inability to keep liquids down
• Severe diarrhea, blood in stool, or signs of dehydration
• Inability to swallow liquids or medicines
• Rapid weight loss or inability to eat
• Uncontrolled bleeding
• Fever or signs of infection, especially during combined chemotherapy
• Blistered, open, draining, or severely painful skin
• Marked swelling of the face, neck, arm, or leg
• Severe urinary pain, inability to urinate, or blood in urine
• Sudden worsening pain after treatment
• Unexpected problems involving a brachytherapy applicator or implant
• Loss, movement, or suspected expulsion of a radioactive seed or source
• A possible radiation-safety incident after systemic treatment
• Any symptom specifically listed as urgent in the treatment instructions

Seek emergency medical care for severe breathing difficulty, signs of stroke, uncontrolled bleeding, loss of consciousness, severe chest pain, or another immediately life-threatening problem.

External-Beam Radiation

No. External-beam radiation does not leave a radioactive source inside the body. Patients are not radioactive after treatment and can ordinarily be around family members, children, pregnant people, and pets.

Temporary Brachytherapy

While an active source is inside the body, hospital or visitor restrictions may be required. Once a temporary source has been removed, the patient is generally no longer radioactive from that source.

Permanent Brachytherapy Seeds

Permanent seeds emit decreasing amounts of radiation over time. Temporary distance and contact precautions may apply. Patients may receive a treatment card describing the implant.

Systemic Radiopharmaceutical Therapy

The body and body fluids may emit radiation for a period. Written safety instructions may cover distance from others, sleeping, bathroom hygiene, laundry, sexual activity, pregnancy avoidance, travel, and handling spills or waste.

Do not use general internet instructions in place of the written precautions supplied by the treating center. The radiation type, dose, and clearance rate determine the required precautions.

Pregnancy Testing and Disclosure

Tell the radiation team immediately if you are pregnant, could be pregnant, or become pregnant during treatment. Radiation exposure to an embryo or fetus depends on the treatment area, dose, technique, and stage of pregnancy. Pregnancy testing may be required before simulation or treatment.

Pregnancy Prevention

Patients who could become pregnant or cause a pregnancy should ask which contraception is recommended and how long pregnancy should be avoided during and after therapy.

Fertility

Radiation involving the ovaries, uterus, testes, pituitary gland, or other reproductive structures may temporarily or permanently affect fertility and hormone production. Total-body irradiation and combined treatments may carry additional risk.

Fertility-preservation options should be discussed before treatment whenever possible. Options may include sperm banking, egg or embryo freezing, ovarian-tissue preservation in selected cases, or moving reproductive organs away from the treatment field through specialized procedures.

Sexual Health

Pelvic radiation may affect vaginal tissue, erections, ejaculation, lubrication, comfort, hormones, and body image. Head, brain, and total-body treatments may also affect hormone production. Ask about preventive care, pelvic-floor therapy, vaginal dilators, erectile-function treatment, counseling, and other rehabilitation.

Breastfeeding

Breastfeeding recommendations depend on the treatment area and whether radioactive medicines are used. Systemic radionuclide treatments may require breastfeeding to stop temporarily or permanently for that child. Obtain exact instructions before treatment.

Tell the radiation team before simulation if you have:

• A pacemaker
• An implanted cardiac defibrillator
• A neurostimulator
• A cochlear implant
• An insulin pump or continuous glucose monitor
• An implanted medication pump
• Metal hardware or prosthetic material
• A prior radioactive implant
• Any other electronic or implanted medical device

Radiation can affect certain devices depending on the dose, beam energy, and distance from the treatment field. The radiation team may coordinate with cardiology, the device manufacturer, or another specialist and arrange device checks before, during, or after treatment.

Do not remove, disable, or alter a medical device without instructions from the appropriate clinical team.

Radiation Before Surgery

Radiation may shrink a tumor, treat microscopic extension, improve the likelihood of complete removal, or support organ-preserving surgery.

Radiation During Surgery

Intraoperative radiation allows treatment of a visible high-risk area while selected normal structures are moved or shielded.

Radiation After Surgery

Postoperative radiation may reduce recurrence risk when pathology shows close or positive margins, lymph-node involvement, aggressive features, or another reason for additional local treatment.

Chemotherapy and Radiation

Chemotherapy may be given before, during, or after radiation. Concurrent chemoradiation can increase effectiveness in selected cancers but may also intensify fatigue, blood-count changes, mouth sores, swallowing problems, bowel symptoms, and other effects.

Immunotherapy and Targeted Therapy

These treatments may be given before, during, or after radiation in selected circumstances. The sequence and combination require careful planning because benefits and toxicities vary by medicine and cancer type.

Hormone Therapy

Hormone therapy may be combined with radiation for selected prostate, breast, and other hormone-sensitive cancers.

Healthy organs have limits on the amount of radiation they can safely receive. Previous treatment to the same or an overlapping area can affect whether additional radiation is possible.

Re-irradiation may still be considered in carefully selected situations. The team evaluates:

• The original treatment area
• The previous total dose and fraction size
• The dose received by individual organs
• The time since previous treatment
• The current tumor’s location and treatment goal
• Available modern targeting techniques
• The expected benefit compared with tissue-injury risk

Tell the radiation oncologist about every previous radiation course, including treatment received many years earlier or at another facility.

Whenever possible, obtain the original radiation plan, dose summary, treatment dates, and facility information. A general statement that radiation was given may not provide enough information for safe planning.

Many short-term radiation effects improve after treatment. Some effects can persist, and others may begin months or years later.

Possible late effects depend on the treatment area and may include:

• Fibrosis, stiffness, or reduced tissue flexibility
• Lymphedema
• Dry mouth, dental damage, or swallowing problems
• Thyroid or other hormone changes
• Heart or lung effects
• Bowel or bladder changes
• Sexual or fertility effects
• Bone weakening or fracture risk
• Cognitive or neurologic changes
• Changes in growth and development in children
• Rare radiation-related second cancers

The possibility of a late effect does not mean it will occur. Risk depends on age, dose, fractionation, organ exposure, genetics, smoking, other cancer treatments, and individual health.

Ask for a radiation-treatment summary and survivorship plan listing the treated area, technique, dates, total dose, fraction schedule, possible late effects, and recommended follow-up.

Nutrition

Nutrition needs depend on the treatment area. Radiation to the brain, head and neck, chest, abdomen, or pelvis may affect appetite, taste, swallowing, nausea, bowel function, or weight.

Tell the team about:

• Unplanned weight loss
• Difficulty chewing or swallowing
• Mouth or throat pain
• Persistent nausea or vomiting
• Diarrhea or constipation
• Loss of appetite
• Difficulty obtaining or preparing food
• Use of supplements or restrictive diets

Hydration

Adequate fluid intake may help prevent dehydration, but recommendations differ for people with kidney, liver, heart, or electrolyte problems. Ask for an individualized target.

Physical Activity

Safe, appropriately paced movement may support strength, function, mood, sleep, and fatigue management. Activity may need modification for anemia, balance problems, bone metastases, pain, heart or lung conditions, neurologic symptoms, or fall risk.

Supportive and integrative care may help manage fatigue, anxiety, pain, sleep problems, nausea, reduced mobility, and emotional distress while the patient continues evidence-based cancer treatment.

Depending on medical approval, services may include:

• Oncology nutrition
• Physical and occupational therapy
• Speech and swallowing therapy
• Pelvic-floor rehabilitation
• Lymphedema therapy
• Supervised exercise
• Mindfulness and relaxation practices
• Psychological counseling
• Support groups
• Spiritual care according to patient preference
• Massage adapted for oncology patients
• Acupuncture for selected symptoms
• Palliative care for symptom control and quality of life

Complementary care should support—not replace—medically indicated radiation therapy.

Do not place herbs, oils, black salve, caustic substances, unapproved creams, or home remedies on irradiated skin. Avoid unverified cancer cures, detox programs, restrictive fasting regimens, or high-dose supplements promoted as substitutes for oncology treatment.

National Center for Complementary and Integrative Health: Cancer and Complementary Approaches

Radiation schedules are designed to produce a particular biological effect. Unplanned treatment gaps can matter for some cancers.

Contact the treatment center as soon as possible if you:

• Cannot attend an appointment
• Are admitted to another hospital
• Develop an infection or new medical problem
• Have transportation difficulties
• Experience side effects that make treatment attendance difficult

The radiation oncologist will decide whether the schedule should remain unchanged, be extended, or be adjusted.

Do not discontinue treatment without discussing the decision with the radiation-oncology team.

Bring a written list, take notes, and consider bringing a trusted support person. Useful questions include:

1. What is the exact name and stage of my cancer?
2. What is the goal of radiation in my situation?
3. How likely is radiation to achieve that goal?
4. What alternatives are available?
5. What may happen without radiation treatment?
6. Will radiation be used alone or with surgery, chemotherapy, hormone therapy, immunotherapy, or targeted therapy?
7. What type of radiation do you recommend?
8. Why is this technique preferred for me?
9. Will I receive photons, electrons, protons, brachytherapy, or a radioactive medicine?
10. What body areas and lymph nodes will be treated?
11. Which nearby organs require protection?
12. What is the total dose?
13. How many fractions or treatment sessions are planned?
14. How long will the entire course take?
15. Will I need a mask, mold, tattoo, applicator, catheter, or implant?
16. Do I need bladder, bowel, fasting, breathing, or medication preparation?
17. What side effects are most likely for my treatment area?
18. Which effects could be permanent?
19. What symptoms require an urgent call?
20. Whom should I contact after hours?
21. How should I care for the treated skin?
22. Which creams, soaps, deodorants, or dressings may I use?
23. Can I continue working, attending school, exercising, driving, or traveling?
24. Could radiation affect fertility, hormones, pregnancy, or sexual function?
25. Should fertility preservation occur before treatment?
26. Are contraception or breastfeeding restrictions necessary?
27. Will I be radioactive after treatment?
28. Do I need to limit contact with children, pregnant people, family members, or pets?
29. Do my pacemaker, defibrillator, pump, or other implanted devices require special monitoring?
30. How will you know whether treatment is working?
31. When should follow-up imaging be performed?
32. What would cause the plan to be changed?
33. Could previous radiation affect this treatment?
34. Would a second opinion or plan comparison be helpful?
35. Could a clinical trial be appropriate?
36. Can I meet with an oncology dietitian, rehabilitation professional, social worker, fertility specialist, counselor, dentist, or financial navigator?
37. Will I receive a written treatment summary when radiation is complete?

Myth: External-beam radiation makes the patient radioactive.

Fact: External-beam treatment does not leave a radioactive source in the body. Patients are not radioactive afterward.

Myth: Radiation treatment is painful while the beam is on.

Fact: Patients generally cannot see or feel the radiation beam. Discomfort may come from positioning, the cancer, inflammation, or side effects rather than the beam itself.

Myth: Radiation always causes hair loss over the entire body.

Fact: Radiation-related hair loss generally occurs only in the treated area.

Myth: Radiation burns the body in the same way as fire.

Fact: Radiation can cause inflammatory skin reactions, but it does not heat or burn tissue like an open flame.

Myth: More side effects mean radiation is working better.

Fact: Side-effect severity does not determine treatment effectiveness.

Myth: Having few side effects means the radiation dose is too weak.

Fact: Response is evaluated through examinations, imaging, laboratory testing, pathology, and long-term cancer control—not by side-effect intensity.

Myth: Proton therapy is always better than photon therapy.

Fact: Proton therapy can reduce normal-tissue exposure in selected cases, but it does not offer a proven advantage for every cancer or patient.

Myth: Stereotactic radiosurgery is an operation.

Fact: Stereotactic radiosurgery is highly focused radiation treatment and does not involve a surgical incision.

Myth: Radiation is used only when cancer cannot be cured.

Fact: Radiation may be curative, reduce recurrence risk, preserve an organ, strengthen another treatment, control metastatic sites, or relieve symptoms.

Myth: Natural creams and herbs are always safe on irradiated skin.

Fact: Some products irritate skin, trap heat, interfere with dressings, or contain substances that are unsafe during treatment. Use only products approved by the radiation team.

Radiation-oncology research includes:

• Shorter evidence-based treatment schedules
• Online adaptive radiation planning
• MRI-guided radiation therapy
• Improved motion tracking and respiratory management
• Artificial intelligence for planning and image analysis
• Proton and other particle therapies
• New brachytherapy techniques
• Targeted radiopharmaceuticals
• Theranostics that pair diagnostic imaging with targeted radioactive treatment
• Radiation combined with immunotherapy or targeted therapy
• Methods to predict radiation sensitivity and resistance
• Strategies to reduce normal-tissue injury
• Re-irradiation methods
• FLASH radiation and other investigational delivery approaches

Some approaches are well established for selected cancers; others remain investigational. Availability alone does not prove that a technology improves survival, cancer control, quality of life, or side effects.

Questions to ask about a trial include:

• What is the study designed to learn?
• How does it differ from standard radiation?
• Is the treatment randomized?
• What are the known and uncertain risks?
• Could participation change the treatment schedule?
• What additional imaging, biopsies, costs, or travel are required?
• What happens if I choose not to participate?

National Cancer Institute Clinical Trials Search

A second opinion may confirm the recommendation, identify a shorter schedule, suggest another technique, clarify whether radiation is necessary, or provide access to specialized brachytherapy, proton therapy, stereotactic treatment, radiopharmaceutical therapy, or re-irradiation expertise.

A second opinion may be especially useful when:

• The cancer is rare.
• The tumor is close to the brainstem, spinal cord, optic structures, heart, bowel, or another sensitive organ.
• The patient previously received radiation.
• Several reasonable schedules or technologies are available.
• The proposed treatment may cause major permanent changes.
• There is uncertainty about whether radiation is needed.
• A highly specialized form of radiation is being considered.

Avoid unnecessary treatment delays. Ask the current team how quickly another review should occur.

Find an NCI-Designated Cancer Center

Radiation costs vary according to the treatment type, planning complexity, number of sessions, facility, imaging, anesthesia, implanted sources, radioactive medicines, and insurance coverage.

Potential expenses include:

• Radiation-oncology consultations
• Simulation and treatment planning
• Daily radiation delivery
• Image guidance
• Medical-physics and dosimetry services
• Brachytherapy procedures and anesthesia
• Hospital stays
• Radiopharmaceutical medicines
• Laboratory and imaging tests
• Supportive medicines and wound care
• Nutrition and rehabilitation services
• Transportation, parking, lodging, or child care
• Reduced work hours or medical leave

Before treatment, ask:

• Is prior authorization required?
• Are the physician and treatment facility in network?
• Is the recommended technology covered?
• Would another evidence-based technique have a different cost?
• Are transportation or lodging resources available?
• Can a financial navigator estimate out-of-pocket costs?
• Does the facility offer financial assistance or payment plans?

National Cancer Institute: Tracking and Managing Cancer-Care Costs

• □ I know the goal of radiation therapy.
• □ I know the exact treatment area.
• □ I understand the recommended radiation technique.
• □ I know the total number of planned treatments.
• □ I understand the simulation process.
• □ I know whether I need a mask, mold, tattoo, applicator, catheter, or implant.
• □ I understand bladder, bowel, fasting, breathing, or medication instructions.
• □ I have provided a complete list of medicines and supplements.
• □ I told the team about all previous radiation treatment.
• □ I told the team about pacemakers, pumps, implants, and electronic devices.
• □ Pregnancy, fertility, contraception, and breastfeeding concerns were discussed.
• □ I know which side effects are expected for my treatment area.
• □ I understand skin-care instructions.
• □ I know which products may be used on treated skin.
• □ I know which symptoms require an immediate call.
• □ I have daytime and after-hours contact numbers.
• □ I know whether I will be radioactive after treatment.
• □ I understand any household or visitor precautions.
• □ Transportation and work or school arrangements have been considered.
• □ I know when response testing and follow-up will occur.
• □ I will request a radiation-treatment summary when therapy is complete.

• National Cancer Institute — Radiation Therapy for Cancer
• National Cancer Institute — External-Beam Radiation Therapy
• National Cancer Institute — Brachytherapy
• National Cancer Institute — Radiation Therapy Side Effects
• National Cancer Institute — Cancer Types and Treatment Summaries
• National Cancer Institute — Radiation Therapy and You
• American Cancer Society — Radiation Therapy
• American Cancer Society — External-Beam Radiation Therapy
• American Cancer Society — Internal Radiation and Brachytherapy
• American Cancer Society — Radiation Side Effects by Body Area
• Cancer Research UK — Radiotherapy
• Canadian Cancer Society — Radiation Therapy
• MedlinePlus — Radiation Therapy
• American Society for Radiation Oncology — Radiation Therapy Patient Resources
• American Society for Radiation Oncology — Quality and Safety
• National Center for Complementary and Integrative Health — Cancer and Complementary Approaches
• National Cancer Institute — Find an NCI-Designated Cancer Center
• National Cancer Institute — Find Cancer Clinical Trials

Radiation therapy is not one machine, one dose, or one treatment schedule. It includes external-beam radiation, brachytherapy, systemic radiopharmaceuticals, and highly specialized techniques designed for different cancers and treatment goals.

For some patients, radiation offers a realistic possibility of cure. For others, it reduces recurrence risk, preserves an organ, strengthens surgery or systemic treatment, controls limited metastatic disease, or relieves pain and other serious symptoms.

Safe radiation care depends on precise simulation, individualized dose calculation, accurate positioning, imaging, quality assurance, protection of nearby organs, early side-effect reporting, and coordination across the cancer-care team.

Patients and families deserve a clear explanation of the treatment goal, expected benefit, alternatives, radiation type, dose and schedule, possible short- and long-term effects, safety precautions, costs, and the plan for evaluating treatment response.