Step-by-Step Guide to Radiation Therapy

Posted on July 11, 2022 in Radiation Therapy

Written by Dr. McCall

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In the wake of a cancer diagnosis, your doctor will begin discussing your cancer treatment plan. Your cancer treatment plan is a roadmap to recovery. This roadmap is designed with the help of many different medical professionals — from radiation oncologists to pathologists — and may include one or more therapies like chemotherapy, immunotherapy, surgery, and radiation therapy.  Track your cancer treatment effectively with our free downloadable Cancer Treatment Plan.

Though radiation therapy, also called radiotherapy, is a localized and typically painless treatment option, it can still be unnerving. To provide our patients with some peace of mind, the radiation oncologists at SERO have created a detailed step-by-step guide to radiation therapy. 

In this guide, you will find more information about the radiation therapy process, tips for preparing for radiotherapy treatment sessions, and more.   

What Is Radiation Therapy?

Radiation Therapy graphic

Radiation therapy is a form of cancer treatment that uses beams of high-energy waves called radiation. Special physicians called radiation oncologists design, oversee, and sometimes deliver the radiation with advanced machines or radioactive substances. Over weeks of treatment, the radiation damages the DNA of the cancer cells. This kills cancer cells and prevents them from spreading (metastasizing). 

Unlike chemotherapy, which affects the entire body, radiotherapy allows doctors to target specific sites while minimizing damage to noncancerous cells. Because of this, radiation therapy is a very popular cancer treatment option. In fact, more than half of cancer patients receive some form of radiotherapy.   

What To Expect From Radiation Therapy

For most patients, radiotherapy is divided into three phases:

  1. Before treatment 
  2. During treatment
  3. After treatment

The duration of each phase depends on the cancer type and stage as well as the type of radiation therapy recommended by your care team. 

However, the before-treatment stage generally lasts a few weeks. This stage is followed by one to ten weeks of radiotherapy sessions. Typically, a patient receives radiation treatments five days per week.  

After you successfully finish your course of radiotherapy, you can expect to remain in the post-treatment phase for two to five years. During this time, your oncology team will monitor for recurrent cancer and lasting side effects of the radiation.

Phase 1: Before Treatment

Treatment begins with two appointments with your radiation oncologist: consultation and simulation

During the initial appointment, or the consultation, he or she will determine if radiotherapy is an appropriate treatment modality for you. If radiation has been recommended, your radiation oncologist will schedule a CT simulation simulation. 

No radiation is actually delivered during simulation. Rather, this preliminary appointment helps your treatment team map the exact area of your body that will be treated. 



The first appointment with your radiation oncologist is critical. During this one- to two-hour meeting, he or she will evaluate your need for radiation therapy by conducting a physical exam and reviewing your medical history. 

Depending on which tests were conducted prior to diagnosis, your doctor may request additional diagnostic imaging tests, including:

  • CT scans
  • MRI scans
  • X-rays
  • Mammograms
  • Ultrasounds 
  • Fluoroscopies
  • PET scans

Your doctor may also request blood work to look for tumor markers and certain blood proteins.

Questions To Ask During Your Radiation Therapy Consultation

Though this consultation can be intimidating, it is important to remember that doctors can only make recommendations — you ultimately choose your cancer treatment plan. Therefore, view this meeting as an opportunity to ask questions about the risks and benefits of radiation therapy. 

Questions you might consider asking include:  

  • How effective is radiation therapy in treating my specific cancer type and stage?
  • Can I continue working throughout my treatment?
  • How frequently will I need to receive radiation and for how long?
  • Will I experience side effects? If so, how soon after radiation?
  • What can I do to mitigate or lessen these side effects?

Consider writing your questions down ahead of time and taking notes throughout the meeting. You may also ask that a friend or family member come to the appointment with you. This person may think of additional questions during the consultation. They can also provide emotional support.

Preparing for Your Radiotherapy Consultation

Preparing your radiotherapy consultation will ensure that the appointment goes smoothly. Besides writing a list of questions, you should also complete any required patient forms and compile other needed documentation before your appointment. 

Other important documents may include:

  • Health insurance card
  • Photo ID
  • Referral authorization letter
  • Referring physician’s name, address, and phone number
  • List of medications (including over-the-counter); note strength and dosage

Finding your radiation oncologist’s office can be difficult, especially if it is located in a hospital. To avoid unneeded frustration, call the front desk and ask for directions ahead of time. You should also ask about parking.



If your radiation oncologist recommends radiotherapy and you decide to move forward with treatment, a second appointment will be scheduled. This appointment is a treatment planning session, also called a simulation. 

Simulation ensures that:

  • Your treatment site is identified and mapped for proper targeting
  • Your are properly positioned for the type of treatment you will receive
  • Damage to healthy tissues is minimized 

You will not receive radiation treatment during this appointment. Rather, your radiation oncologist will use a CT scanner — a piece of equipment similar to an X-ray machine — to identify the area of your body that will receive treatment in the future. You will be positioned in the most optimal way for treatment. Sensitive parts of your body may be exposed for your simulation and treatment. You may have small marks drawn or tattooed on your skin, and stickers are often used. 

Though every patient’s experience is different, simulation usually takes about an hour.

Preparing for Simulation

Oftentimes, patients will receive very specific instructions prior to simulation. These instructions vary depending on the area of the body being treated. 

For example, your care team may ask that you:

  • Complete a bowel preparation
  • Fill or empty your bladder
  • Follow specific dietary restrictions (not eating after a certain time)
  • Take medications prior to the appointment
  • Practice breathing exercises
  • Practice holding certain positions 

Women of childbearing age are often asked to take a pregnancy test prior to simulation. Patients may also be asked to remove their continuous glucose monitor or insulin pump. However, be sure to speak with your radiation oncologist before removing any medical device. 

During simulation, you will likely be lying in one position for an extended period of time. If you think this will cause pain or discomfort, consider taking an over-the-counter pain reliever like Tylenol prior to your appointment. If you think you will become anxious during simulation, your radiation oncologist may prescribe an anti-anxiety medication.  

What To Expect Before Simulation

On the day of your simulation, you should arrive at least 15 minutes early and be prepared to complete additional patient paperwork. You should also be prepared to sit in the waiting room for a short period of time. To help yourself relax, bring a book, a crossword puzzle, or even download a game onto your phone.  

When the radiation therapist calls your name, they will walk you to the simulation room. He or she will then explain the simulation to you and answer any questions you may have. You will then be asked to change into a gown.

What To Expect During Simulation

After changing, your radiation therapist will help you lie down onto a table in the simulation room. This table will be covered by a sheet or paper-like protector, but it is not cushioned. If you think you may need pain medication, let your radiation therapist know before the simulation begins. 

Throughout your simulation, the table will move in different positions. Red laser lights will also be projected onto the walls. These lights help the radiation therapist position you on the table. Since these laser beams can damage your eyes, do not look directly at them. 

Depending on which area of your body is being treated, your radiation therapist may position you on your stomach, back, or side. If you are ever uncomfortable, let your radiation therapist know. Though your radiation therapist may walk in and out of the room during simulation, a microphone allows them to hear and speak to you.

Simulation Imaging

During simulation, the radiation therapist will perform a CT scan of your body. This scan will create images that help your radiation therapy team map out treatment.  

Your CT scan should take about 45 minutes. Though holding certain positions may be uncomfortable, you should never experience any pain. If you do, tell your radiation therapist right away. They will be able to hear you over the machine, which makes very loud clicking and whirring noises.

Skin Markings

After this procedure, the radiation therapist will define your treatment area with a felt marker or small permanent tattoos. These tattoos are the size of a pinhead and are created using a sterile needle and ink. Visual markers help doctors deliver radiation to the same spot during treatment. 

Immobilization Devices

Some patients also require an immobilization device. An immobilization device is a mold, cast, or headrest that holds your body in the same position during each radiation session. If you are getting radiation to the head or neck area, for example, you may be fitted for a mask. This mask is made of mesh and keeps your head from moving during treatment. 

Phase 2: During Treatment

After simulation, your radiation oncologist will use the images obtained during the CT scan to determine an effective treatment plan. Depending on the severity of your cancer, your radiation may begin one to ten days after simulation

Many patients fear radiation therapy simply because of uncertainty; they are unsure of what to expect. Fortunately, radiotherapy is a typically painless and localized cancer treatment option.


What To Expect Before Radiation Therapy

When you check-in for your first radiation therapy session, you will again be asked to sit in the waiting room. You may feel more nervous now than you did before your simulation. If so, try relaxing with some funny videos on your phone or with breathing exercises. 

Some other tips for relaxing include:

  • Bringing headphones to listen to your favorite music
  • Focusing on positive thoughts — finding your “happy place”
  • Meditating or praying
  • Speaking with a fellow patient
  • Scheduling something fun after treatment, like a picnic or movie 

You can also bring a friend or family member to your treatment sessions. Loved ones can provide much-needed support during these stressful times. However, they will be asked to stay in the waiting area during your treatment.


What To Expect During Radiation Therapy

After the radiation therapist calls your name, you will change into a gown. Much like during simulation, you will be moved to a room where your radiation therapy team will explain your treatment plan. They will also answer any questions you may have. 

From there, your radiation therapist will help you lie down on a treatment table. They will then position you on the table and set up the equipment. If needed, the radiation therapist will also place you in immobilization devices like headrests or casts. This entire process takes five to 15 minutes. 

Once you are positioned correctly, the radiation therapist will leave the room and go into an adjoining room. They will then begin the radiation therapy session. Treatment typically lasts between five and 30 minutes. 

It is painless, though you may be asked to hold your body in certain positions for extended periods of time. The machine may also make loud whirring, clicking, and vacuum-like noises. If you ever feel uncomfortable during treatment, let your radiation therapist know.


What To Expect After Your First Radiation Treatment

Most patients receive radiation therapy five days per week for three to ten weeks. Your radiation oncologist will monitor your daily treatment and may modify the intensity, duration, or frequency of radiation based on your progress. 

Your progress will be tracked using blood tests, X-rays, and other imaging tests. Since radiation therapy works very slowly, you may not notice any changes in your body at first. Side effects can develop over time and your doctor will talk with you about what to expect. 

Regardless, you must continue your course of radiation treatment. Skipping treatment sessions makes treatment less effective. It also increases the likelihood that your cancer returns. 

Phase 3: After Treatment

Cancer care does not end after you complete a course of radiation therapy. In most cases, your cancer care team will create a follow-up plan that calls for regular medical checkups with either your radiation oncologist or regular oncologist. 

The first checkup is typically scheduled four to six weeks after you finish radiation treatment. From there, appointments are often scheduled every three to four months for the first two to three years after treatment. 

During these appointments, your doctor may order specific blood tests or imaging tests like CT scans and MRIs. The goal of these appointments is to monitor side effects caused by radiation and to monitor for recurrent cancer.     

What to Expect From Brachytherapy

So far, we have discussed what happens during the most common type of radiotherapy — external beam radiation therapy. During this treatment, a machine directs beams of radiation at your cancer. 

However, the process differs for patients receiving internal radiation therapy (brachytherapy). During brachytherapy, radioactive pellets are placed inside or next to cancerous lesions, either temporarily or for an extended period of time.  

What Happens Before Brachytherapy?

Regardless of the type of radiotherapy, all patients must schedule an initial consultation. During this consultation, your radiation oncologist will determine if radiotherapy is appropriate for your cancer type and stage. He or she will also answer any questions you may have.  

Since internal radiation therapy involves placing a radiation source inside the body, there is no need for a simulation appointment.

What Happens During Brachytherapy?

There are two types of brachytherapy: low dose rate (LDR) and high dose rate (HDR). Which type your radiation oncologist recommends will determine what your treatment sessions look like.


LDR Brachytherapy

During LDR brachytherapy, radioactive seeds are placed inside the body. To implant these seeds, the patient is typically placed under general anesthesia. The procedure is outpatient, meaning you can go home the same day.   

In most cases, the radioactive pellets remain inside the body forever. However, they only give off radiation for a few months. 


HDR Brachytherapy

During HDR brachytherapy, a radioactive source is placed inside the body for a few minutes and then removed. 

For example, during HDR prostate brachytherapy, a patient is placed under general anesthesia and thin tubes are inserted into the prostate. Later, during treatment sessions, wires containing radioactive sources are fed through the tubes and left inside the prostate for a few minutes at a time. 

This process is repeated several times, depending on the cancer’s severity. The tubes are later removed.

What Happens After Brachytherapy?

After brachytherapy, your cancer care team will create a follow-up plan. This plan will call for regular medical checkups, either with your radiation oncologist or regular oncologist. 

The first follow-up appointment will be scheduled four to six weeks after you finish treatment. From there, appointments are typically scheduled every three to four months for several years. 

There are two primary goals of follow-up care: to monitor lasting side effects and to watch for recurrent cancer. To accomplish these goals, your doctor may order imaging tests like ultrasounds and MRIs. He or she may also order blood tests. 

Questions To Ask Your Radiation Oncologist

Since internal radiation therapy procedures can vary, patients must ask their radiation oncologists the right questions. 

Some questions you may consider asking include:

  • Will my treatment require outpatient surgery? Will it require local anesthetics?
  • Will I have to be hospitalized during my treatment?
  • What will the implantation process feel like? Will there be any pain during or after?
  • How many HDR brachytherapy sessions will I receive?
  • How long will the LDR brachytherapy pellets release radiation? 

As you receive treatment, your radiation oncologist will monitor your progress and make modifications as needed. Additional imaging tests like CT scans and ultrasounds may be ordered in the weeks following your treatment.

How To Prepare for Radiation Therapy

Cancer diagnosis and treatment affect all aspects of a patient’s life, not just their health. Depending on your cancer type and stage, you may have to take a break from work or move in with a family member. You may not be able to enjoy your favorite hobbies, like mountain biking or fly fishing, and you may not have the energy to hang out with close friends. 

Though these are challenging changes, proper planning can make radiation therapy less stressful. At SERO, we advise patients to prepare physically, emotionally, and financially for the treatment ahead.



Radiation therapy works by delivering high doses of radiation to cancer cells. Unfortunately, healthy cells can be affected too. This can lead to fatigue, skin blistering, and even infertility. Quitting smoking can be one way to lessen these unwanted side effects. Eating healthy, drinking enough water, and staying active can also help. 



In cancer patients, mental health problems are often under-diagnosed. However, anxiety and depression should not be ignored. In the wake of your diagnosis, consider exploring healthy ways to relax like meditating and exercising. 

You should also turn to your support system — a group of people you can trust and rely on. You may need to ask these individuals for travel assistance or help with household chores. 

If you begin experiencing panic attacks, insomnia, or troubling thoughts, you should consult a medical professional. Your doctor can prescribe helpful medications or refer you to a psychologist.



In cancer patients, mental health problems are often under-diagnosed. However, anxiety and depression should not be ignored. In the wake of your diagnosis, consider exploring healthy ways to relax like meditating and exercising. 

Navigating the financial impact of cancer can be overwhelming, especially since the average cost of cancer treatment is $150,0002. If you have health insurance for cancer treatment, become familiar with your policy to understand what is covered. You should also call your insurance company to determine if medical treatments and procedures require prior approval. 

If you are not insured, begin exploring financial assistance programs. Many national and regional organizations help defray the costs associated with cancer treatment. Certain hospitals also provide charity care to low- to moderate-income patients. Your SERO doctor may be able to connect you with social workers who can help navigate options to help with costs.

Tips for Caregivers

Depending on a patient’s cancer type and stage, they may require a cancer caregiver to provide regular support, such as transportation to radiation therapy sessions or help cleaning. 

In most cases, this role is filled by a spouse, child, parent, family member, or friend. These individuals often juggle full-time employment with caregiving, a duty that typically requires more than 30 hours of work per week3. Though caregiving can be fulfilling, it can also be demanding and stressful. 

To avoid caregiver burnout, a state in which a caregiver becomes physically, emotionally, and mentally exhausted, SERO suggests:

  • Asking for help from other friends or family members
  • Giving yourself permission to leave the house and have fun
  • Making time for yourself, even just 15 minutes to read or meditate
  • Researching family leave benefits
  • Considering hospice respite care for your loved one

Treat Cancer With SERO

Radiation therapy is an effective, localized, and often painless cancer treatment option. However, like all cancer treatment modalities, radiotherapy can still be physically and emotionally taxing. That is why SERO’s providers are dedicated to providing compassionate care and support when you and your family need it most. 

To learn more about the radiation therapy process, contact us to schedule an appointment at one of our cancer treatment centers. We offer convenient radiation oncology services at dozens of locations in the Charlotte area.