Radiation Therapy

MRI-guided radiation therapy is a non-invasive radiation therapy that can image and treat cancer patients simultaneously. By combining high-strength magnetic resonance imaging (MRI) with a linear accelerator, the MRI-LINAC targets and tracks the position and shape of a patient’s tumor while radiation is delivered in real-time. This allows for enhanced precision and accuracy compared to conventional radiation therapy.

Click here to learn more about MRI-Guided Radiation Therapy.

External beam radiation therapy (EBRT) refers to radiation that is delivered from outside the body through a machine, often called a linear accelerator. It carefully aims high-powered X-rays or particles directly at the tumor. At Northside Hospital Cancer Institute, external beam radiation therapy may include delivery through any one of the various methods below:

• Conventional Radiation Therapy – One or more radiation beams are positioned around the patient to deliver the prescribed therapeutic dose of radiation to the targeted area. A team of physicians, medical dosimetrists, and medical physicists work together using various forms of imaging to create a treatment plan to accurately deliver the dose where intended.
• Intensity-Modulated Radiation Therapy (IMRT) – Intensity-modulated radiation therapy (IMRT) employs multiple small radiation beams of varying intensities to radiate a tumor with great precision. IMRT involves computed tomography (CT) images and computerized dose calculations to modulate the intensity of the radiation beams so that they conform to the tumor’s three-dimensional shape. Advantages of IMRT include the safe delivery of higher and more effective radiation doses with fewer side effects, as well as reduced treatment toxicity.
• Volumetric Modulated Arc Therapy (VMAT) – Volumetric modulated arc therapy takes conventional IMRT a step further, delivering radiation with remarkable precision over a shorter treatment time. The treatment machine rotates 360 degrees around the patient to deliver the radiation to the tumor from multiple angles. This precision reduces the chance of tumor movement during treatment and preserves surrounding healthy tissue.
• Image-Guided Radiation Therapy (IGRT) – Image-guided radiation therapy (IGRT) uses frequent imaging during radiation therapy to provide real-time positioning and targeting of select tumor(s). This added accuracy allows radiation to be delivered to a tumor based on its exact location in the body which keeps nearby normal tissues protected and allows for reduced treatment-related side effects

Frameless stereotactic radiosurgery (SRS) is a highly precise form of radiation therapy that delivers focused external beam radiation therapy with an accuracy of within one-to-two millimeters. SRS is a non-surgical radiation therapy that can be used as an alternative to invasive surgery. This method allows providers to treat very small tumors, located in hard-to-reach places in shorter treatment times than traditional radiation therapy.

Stereotactic body radiotherapy (SBRT) employs the same principles of SRS to deliver precise radiation for treatment of malignant or benign small-to-medium size tumors in the body. SBRT is usually prescribed for one-to-five sessions over the course of one-to-two weeks.

At Northside Hospital Cancer Institute, we offer Gamma Knife^® Icon™, a form of stereotactic radiosurgery and is an advanced form of radiation therapy. Though the name sounds like a surgical procedure, Gamma Knife^® is actually a non-invasive alternative to traditional brain surgery that does not involve any scalpels or incisions. Instead, it uses up to 192 of focused beams of radiation to treat malignant and benign brain tumors, vascular normalities and functional disorders without harming surrounding healthy tissue. The thousands of radiation beams can be generated from these sources with a level or accuracy of better than 0.15 mm. By using so many beams, this allows the optimal treatment plan to be generated to treat the target and at the same time minimize the amount of radiation to the surrounding healthy tissue. Due to the accuracy of the Gamma Knife^® Icon™ and the ability to use either a frame or a mask for patient immobilization the full dose of radiation can be delivered during a single session, or using multiple smaller doses. Treatments are delivered in the outpatient setting and the patient can return home the same day after the treatment is completed.

High dose-rate (HDR) brachytherapy is an internal radiation therapy that delivers doses of radiation from implants placed inside or very close to the tumor. It allows for delivery of the maximum dose of radiation to the cancerous tissues, with minimal exposure to the healthy surrounding tissues. This technique allows a maximum dose of radiation to be delivered to the cancerous tissues while limiting the radiation exposure to the healthy surrounding tissues. Upon completion of the treatment, the radioactive source and the applicator are removed. Brachytherapy is a quick, effective therapy used for partial breast, gynecologic, lung and prostate cancers.

Prostate seed implantation is a low-dose form of brachytherapy in which radioactive seeds are implanted directly into the prostate gland. This treatment allows the prostate gland to receive a high dose, while limiting that dose to surrounding structures and tissue. This treatment is often combined with external radiation for optimum treatment outcomes and disease control. It is an outpatient procedure that is performed by a radiation oncologist and urologist.

Image-Guided Radiation Therapy (IGRT) uses frequent imaging during radiation therapy to provide real-time positioning and targeting of select tumor(s). This added accuracy allows radiation to be delivered to a tumor based on its exact location in the body. Images are obtained of the patient while on the treatment table and in their treatment position. The treatment machine is equipped with special imaging technology that allows imaging immediately before and during the time the radiation is delivered. Using specialized computer software, the images are compared to reference images taken during simulation. Any necessary adjustments are made to the patient’s position or radiation beam in order to achieve precise and accurate treatment delivery to the treatment area while avoiding surrounding healthy tissues.

At NHCI, we use AlignRT^® surface-guided radiation therapy (SGRT) technology to ensure patients are positioned correctly before and during treatment. Using three cameras to monitor thousands of points on a patient’s skin, it can automatically signal for the treatment delivery system to pause radiation if the patient moves out of the desired position.

While it can be used to assist with the treatment of a majority of radiation patients, there are certain procedures offered at Northside where the technology is an essential tool for treatment. For example, Deep Inspiration Breath Hold, or DIBH is a technique designed to minimize radiation dose to the heart for patients receiving radiation to their left breast. By taking a deep breath during treatment the patient’s heart moves away from the breast tissue therefore reducing the heart dose.

Accelerated partial breast irradiation (APBI) is a form of brachytherapy used to treat breast cancer after a lumpectomy. Because the treatment works from inside the breast, a higher daily dose of radiation can be used for a shorter period of time (five days) and has fewer side effects than other radiation therapies that are done over the course of several weeks. The procedure involves inserting a small balloon inside the lumpectomy cavity; the balloon is attached to a catheter through which the high dose radiation treatment is delivered. Once treatment is completed, the catheter and balloon are removed and the patient can return to normal daily activities.

CT simulation with 4D Gating assists the radiation oncologist with planning for the delivery of radiation to tumors that move when the patient breathes. Using an infrared camera connected to a CT scanner, four-dimensional images are generated in a clear video sequence that shows exactly how the tumor moves during the patient’s normal breathing cycle. Clinicians are then able to determine how to deliver the desired radiation dose to the tumor with the most precision and with minimal risk of damaging healthy surrounding tissue.

Total body irradiation (TBI) involves irradiation of the entire body and is used primarily to prepare patients who are undergoing stem cell transplantation for hematologic conditions such as leukemia or lymphoma. TBI suppresses the immune system and kills diseased bone marrow cells, which helps reduce the risk of the patient’s body later rejecting transplanted tissue and increases the likelihood of a successful transplant.

During the consultation visit, you will first meet with a member of our nursing staff, who will review your medical history, medications and current health issues. This information will be shared with the radiation oncologist, who will explain to you how radiation works and discuss your treatment options. The physician will discuss a proposed course of treatment (what type of radiation and how many treatments you will receive) and the potential side effects that you might experience due to your radiation treatments.

If the decision is made to proceed with radiation treatments, the next step will be a CT simulation. During CT simulation, you are placed in a specific treatment position (depends on what part of the body is being treated) and CT images are obtained. The images are used by the radiation oncologist to determine the exact size and location of your treatment area.

It is very important that the position of your body during your CT scan be reproduced during each treatment. Often custom masks, body molds and other immobilization devices are used to assist in maintaining that position during treatment. Temporary skin marks are made on your body to help the radiation therapist position you correctly on the treatment machine. It will be necessary for you to maintain these marks until your first treatment appointment.

The treatment planning process is done without you (the patient) being present and can take several days depending on the complexity of your radiation treatment plan.

In this step, the radiation oncologist will use the CT images that were obtained during your CT simulation as well as other imaging including MRI’S and Nuclear Imaging that may be beneficial to developing a robust treatment plan. The radiation oncologist works with a dosimetrist and physicist to design a computer-generated treatment plan. This involves identifying the tumor and anatomical structures that are located near the tumor or could be included in the treatment area. These structures are outlined, also known as contouring, on each of the CT images, which are loaded into a special treatment planning computer. Once the contouring is complete, the treatment fields are designed. The treatment fields represent the shape of the radiation and the angle of the treatment machine in which the radiation will be delivered. The treatment plan specifies the amount of radiation to be delivered and the number of treatment sessions needed to deliver the prescribed treatment plan.

The treatment plan is then reviewed by your radiation oncologist and physicist to verify that the treatment plan is meeting the physician’s prescribed course of treatment. This review and approval of the treatment plan must be completed prior to the computer plan being used in the delivery of your radiation treatments.

Your first day on the treatment machine is often referred as your treatment verification visit and will take more time than your daily treatment visit. Due to the amount of time needed for this visit (at least 30 minutes), patients often do not receive an actual treatment until day two.

Prior to entering the treatment room, you might be asked to change into a gown. The radiation therapist will then escort you into the treatment room and position you on the treatment couch. If an immobilization device was used during your CT simulation, it will be placed on the patient at this time. The skin marks (you received during your CT simulation) and the alignment lasers will be used to place you in the correct treatment position. At this time, X-ray images will be taken with the treatment machine of your treatment fields and reviewed by the radiation oncologist. These X-ray images will be compared to images created during the design of your treatment plan in order to confirm the correct area and radiation dose will be delivered during your treatment. Adjustments will be made to your skin marks as needed based on these X-ray images and will need to be maintained throughout your course of treatment. You will then be assisted off the treatment table.

On day two and for your remaining treatment days, you will be placed on the treatment table and placed in your treatment position. The treatment machine, or linear accelerator, will deliver the radiation by moving around you at the appropriate angles based on your treatment plan. Radiation is not visible so you will not see or feel anything while the machine is on. X-ray images will be taken throughout your course of treatment. X-ray frequency will be determined by your radiation oncologist. These images are used to verify that your treatment is being delivered as prescribed by your treatment plan.

During your course of treatment you will be seen weekly by the nursing staff and your radiation oncologist, which provides you with the opportunity to ask questions and discuss any treatment-related problems you might be experiencing.

On the last day of treatment, you will be given an appointment to return to see your radiation oncologist to continue to monitor the results of your treatment. The frequency of these follow-up appointments will be determined by your radiation oncologist.

You may also receive information on surveillance, managing potential late or long-term effects, and maintaining or improving overall health with a survivorship care plan and “Finding your True North: A Survivor’s Guide to Living Well.” Learn more about our radiation oncology survivorship program.

Radiation kills cancer cells by destroying their ability to reproduce. Radiation also affects normal cells. Therefore, the prescribed course of radiation is given over many days or weeks, which allows your normal cells to have the necessary time to repair themselves between treatments.

You will not experience any pain or discomfort from the radiation during your treatment. You will be required to hold very still during your treatment to ensure the radiation is being delivered to the correct area. A custom immobilization device is used to assist you in maintaining the correct position during treatment.

Radiation treatments are given daily, usually Monday thru Friday. The number of treatments that are prescribed by the radiation oncologist will depend on the type and stage of your cancer. The amount of time that you will spend on the actual treatment machine will depend upon the complexity of your treatment. The majority of the time spent will be to ensure you are in the correct treatment positon before we turn on the treatment machine. The actual delivery of the radiation treatment only takes a few minutes.

When patients receive external radiation, once the treatment machine is turned off, there is no lingering radiation and you are not radioactive. However if you should receive internal radiation (brachytherapy) and radioactive sources are implanted into the disease site, low levels of radiation can be emitted from your body for a limited time following treatment. During this time, you will receive special instructions on what to do to reduce exposure to others.

Our treatment rooms and machines are very open and spacious and patients do not usually experience claustrophobia. For our rare patients who do experience claustrophobia, it is typically during the CT scan or if an immobilization mask is needed during treatment when there is a problem. Often the mask can be modified so that it is not so confining. Ativan, a medication that helps to reduce anxiety, often is given to patients that experience claustrophobia prior to treatment. Communication and visual monitoring of the patient is maintained throughout the treatment delivery in the event that the patient should experience any problems.

The actual radiation treatment will not impair your ability to drive. Most of our patients are able to drive themselves for their daily treatments and continue their normal work routine while receiving their treatments. Your radiation oncologist will speak to you in more detail regarding your unique circumstances. Individual physical limitations or medications that could impair your ability to drive should be discussed with your physician.