Radiation Therapy

Overview of Radiation Oncology Program at Mount Sinai

Radiation oncology is an integral part of Mount Sinai’s cancer care, often offered in combination with surgery and/or chemotherapy. Our radiation oncologists work closely with other specialists to offer a multidisciplinary approach to cancer care. Like our specialists in other fields, our radiation oncologists are involved in research and teaching, which keeps them at the forefront of knowledge in the field. The Mount Sinai Comprehensive Cancer Center is the first and only program in South Florida to receive full accreditation for its radiation therapy oncology programs at the main campus as well as Mount Sinai Aventura departments from the American College of Radiology.

Radiation oncology is constantly evolving as scientists explore more effective techniques for delivering radiation therapy. Mount Sinai’s commitment to offering patients the best care ACR accredited facility logomeans that we invest in cutting-edge technology. Our experienced team of radiation oncologists is supported by a professional support staff, all dedicated to providing state-of-the-art treatment in a caring and supportive environment.

About Radiation Therapy

Radiation therapy, or radiotherapy, is the use of various forms of radiation to safely and effectively treat cancer and other diseases. Radiation therapy works by damaging the genetic material within cancer cells and limiting their ability to successfully reproduce. When these damaged cancer cells die, the body naturally eliminates them. Normal cells are also affected by radiation, but they are able to repair themselves in a way that cancer cells cannot. In addition, a radiation oncologist develops a plan to deliver the radiation to the tumor area, shielding as much surrounding normal tissue as possible.

A radiation oncologist may recommend using radiation therapy in a number of different ways. Sometimes the goal is to cure the cancer. In this case, radiation therapy may be used to:

  • Destroy tumors that have not spread to other parts of your body and cure you of disease.
  • Reduce the risk that cancer will return after you undergo surgery or chemotherapy by killing small amounts of cancer that might remain.
  • Shrink the cancer before surgery.
  • Chemotherapy and radiation are sometimes given together to enhance the effectiveness of both treatments.

In other cases, the goal is to reduce the symptoms caused by growing tumors and to improve your quality of life. When radiation therapy is administered for this purpose, it is called palliative care or palliation. In this instance, radiation may be used to:

  • Shrink tumors that are interfering with your quality of life, such as a lung tumor that is causing shortness of breath.
  • Relieve pain by reducing the size of a tumor.

It is important for you to discuss the goal of your treatment with your radiation oncologist.

Radiation therapy has been used safely and effectively to treat diseases for more than 100 years. What are the different kinds of radiation?

The goal of radiation therapy is to get enough radiation into the body to kill the cancer cells while preventing damage to healthy tissue. There are several ways to do this. Depending on the location, size and type of cancer, you may receive one or a combination of techniques. Your treatment team will help you to decide which treatments are best for you.

Radiation therapy can be delivered in two ways, externally and internally. During external beam radiation therapy, the radiation oncology team uses a machine to direct high-energy X-rays at the cancer. Internal radiation therapy, called brachytherapy, involves placing radioactive sources (for example, radioactive seeds) inside your body.
External Beam Radiation Therapy

During external beam radiation therapy, a beam (or multiple beams) of radiation is directed through the skin to the cancer and the immediate surrounding area in order to destroy the main tumor and any nearby cancer cells. To minimize side effects, the treatments are typically given five days a week, Monday through Friday, for several weeks. This allows enough radiation to get into the body to kill the cancer while giving healthy cells time to recover.
Three-Dimensional Conformal Radiation Therapy (3D-CRT)

Tumors are not regular; they come in different shapes and sizes. Three-dimensional conformal radiation therapy, or 3D-CRT, uses computers and special imaging techniques such as CT, MRI, or PET scans to show the size, shape and location of the tumor as well as surrounding organs. At Mount Sinai Medical Center, radiation oncologists precisely tailor the radiation beams to the size and shape of your tumor with multileaf collimators or custom fabricated field-shaping blocks. Because the radiation beams are very precisely directed, nearby normal tissue receives less radiation and is able to heal more quickly.
Intensity Modulated Radiation Therapy (IMRT) and Rapid Arc (RA)

Intensity modulated radiation therapy, or IMRT, is a specialized form of 3D-CRT that allows radiation to be more exactly shaped to fit the tumor. With IMRT, the radiation beam can be broken up into many “beamlets,” and the intensity of each beamlet can be adjusted individually. Using IMRT, it may be possible to further limit the amount of radiation received by healthy tissue near the tumor. In some situations, this may also safely allow a higher dose of radiation to be delivered to the tumor, potentially increasing the chance of a cure. Mount Sinai Medical Center was the first radiation oncology facility in South Florida to use RapidArc technology, an advanced form of IMRT. RA allows IMRT to be delivered to the patient in the shortest amount of time while further improving the accuracy of treatment.
Image Guided Radiation Therapy (IGRT)

Radiation oncologists use image guided radiation therapy, or IGRT, to help better deliver the radiation to the cancer since tumors can move between treatments due to differences in organ filling or movements while breathing. IGRT involves conformal radiation treatment guided by imaging, such as CT, ultrasound or X-rays, taken in the treatment room just before the patient is given the radiation treatment on a daily basis. Our 4D treatment console computer robotically moves the treatment table to the precise position required for accurate treatment delivery.
Stereotactic Radiation Therapy

A specialized type of external beam radiation therapy called stereotactic radiation uses focused radiation beams targeting a well-defined tumor, relying on detailed imaging, computerized three-dimensional treatment planning and precise treatment set-up to deliver the radiation dose with extreme accuracy (i.e., stereotactically).

There are two types of stereotactic radiation:

  • Stereotactic Radiosurgery (SRS) refers to a single or several stereotactic radiation treatments of the brain. SRS is delivered by a team that includes a radiation oncologist and a neurosurgeon.
  • Stereotactic Body Radiation Therapy (SBRT) refers to one or several stereotactic radiation treatments within the body.

SRS/SBRT is best for very small tumors. Doctors use specialized scans to pinpoint exactly where within the body the tumor target is located. Customized immobilization devices will be used to keep the body perfectly still during treatment. Some tumors also require the treatment machine to adjust for breathing motion. These techniques, utilizing the Trilogy at Mount Sinai Medical Center, allow doctors to give a high dose of radiation to the tumor in a short amount of time. SRS/SBRT is a type of external beam radiation therapy that can be completed in one to five days rather than over several weeks.

Brachytherapy is the placement of radioactive sources in or just next to a tumor. During brachytherapy, the radioactive sources may be left in place permanently or only temporarily.

There are two main types of brachytherapy:

Intracavitary treatment and interstitial treatment. With intracavitary treatment, the radioactive sources are put into a space near where the tumor is located, 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 or breast.

High-dose-rate (HDR) brachytherapy involves the remote placement of a high intensity radiation source, accurately directed by your radiation oncologist and team, into the tumor for several minutes using specialized tubes or applicators. It is usually given in multiple doses once or twice daily or once or twice weekly. Using the VariSource high-dose-rate remote afterloader, Mount Sinai Medical Center radiation oncologists can deliver a brachytherapy treatment quickly and accurately, in about 10 to 20 minutes.

Low-dose-rate (LDR) brachytherapy involves the longer placement of the temporary (several days) or permanent radiation sources into the tumor area. Mount Sinai Medical Center radiation oncologists, working with Columbia University urologists at Mount Sinai, have one of the largest office experiences with prostate brachytherapy having performed over 2,000 prostate brachytherapy seed implants.

Depending on the type of brachytherapy you receive, you may need to take some precautions after your treatment, particularly if you plan to be around young children or pregnant women. This impacts only those with permanent implants, not temporary implants as they are removed after treatment. Ask your radiation oncologist or radiation oncology nurse about anything special you should know.

Brachytherapy may be used alone or in conjunction with external radiation treatments. Your radiation oncologist will advise you of the sequencing of these treatments that is appropriate for you.

Brachytherapy techniques are available at Mount Sinai for the treatment of cancers of many different organs including breast, lung, uterus and prostate. Mount Sinai Medical Center was one of the first hospitals in the nation to use balloon-based brachytherapy for the treatment of breast cancer. This treatment allows a full course of radiation to be given in one treatment week as opposed to several weeks for conventional treatment.


The Department of Radiation Oncology uses some of the most advanced technology available to customize treatment plans for each patient.

Varian Trilogy linear accelerator
Varian 2100C/D linear accelerator
Varian 21EX linear accelerator
VariSource High Dose Rate (HDR) Remote Afterloader
Phillips Wide-Bore CT Simulator
3-D conformal treatment planning
IMRT/RA treatment planning
Onboard imager for daily cone-beam ct and MV/kV filming
Intra-operative radiotherapy

The linear accelerators, HDR brachytherapy system, simulators, daily image guidance and computerized treatment planning systems allow for the precision needed to plan and deliver individually tailored treatment required for the many types of cancer patients.

The Trilogy™ system from Varian delivers Image Guided Radiation Therapy (IGRT), intensity modulation radiotherapy (IMRT), RapidArc (RA) and stereotactic radiosurgery (SRS). It represents a major advance in radiation oncology, because it has one of the most accurate systems of targeting tumors available. This results in decreased side effects and lower complication rates.
Radiation Oncology Team at Mount Sinai

In addition to your radiation oncologist, there are a number of other healthcare professionals who help ensure you are getting the best treatment possible.

Medical radiation physicist

Medical radiation physicists measure radiation beams to ensure that the radiation is accurately targeting your tumor and sparing as many normal cells as possible. They work with the radiation oncologist and dosimetrist to make sure that treatments are administered safely and effectively. Medical radiation physicists are also responsible for the quality assurance of all treatment techniques.


Dosimetrists calculate the dose of radiation used to destroy your tumor. They work with the radiation oncologist and medical radiation physicist to develop and choose the treatment plan that is best for each patient.

Radiation therapist

Radiation therapists administer radiation treatments under the radiation oncologist’s supervision. They also maintain daily reports and check the treatment machines to help ensure they work properly.

Radiation oncology nurse

Radiation oncology nurses care for cancer patients during the course of their radiation treatment. They also educate patients and their families about treatment and potential side effects.
Patient Support Services

At Mount Sinai, we understand fighting cancer involves more than treating the disease. It means taking care of the whole person. Click here to learn more about our support services and counseling, including nutritional counseling, psychosocial services, pain management, patient resource center and support groups.
Side Effects

During radiation therapy, every effort is made to minimize the amount of exposure normal cells have to radiation, but some exposure will occur. This exposure may result in side effects. Click here for more information about side effects.

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