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Radiation Oncology

John M. Anderson, M.D.


  • Undergraduate: State University of New York, Albany
  • Graduate: University of Virginia, Charlottesville
  • Medical School: University Of Arizona – College Of Medicine, Tucson
  • Residency: Tucson Medical Center, Tucson
  • Fellowship: University of Arizona – College of Medicine, Tucson


Our Radiation Oncology Therapies

3D Radiation Therapy (3D-CRT)

3D radiation therapy (also called three-dimensional radiation therapy) uses computer technology to create a three-dimensional picture of the tumor so that multiple radiation beams can be shaped exactly (conform) to the contour of the treatment area. This is particularly useful when the tumor has an irregular shape. It allows doctors to give the highest possible dose of radiation to the tumor, while sparing the surrounding normal tissue as much as possible.

Intensity Modulated Radiation Therapy (IMRT)

Intensity Modulated Radiation Therapy is a state-of-the-art cancer treatment method that delivers a higher concentration of radiation doses directly to cancer cells with a more precise targeting mechanism than is possible with conventional radiotherapy. This therapy can deliver higher radiation doses directly to cancer cells while sparing more of the surrounding normal tissues. It uses computer-generated images to plan and then deliver tightly focused radiation beams to cancerous tumors. Clinicians use it to exquisitely “paint” the tumor with a precise radiation beam that conforms as closely as possible to the shape of the tumor.

IMRT can be used to treat tumors that might have been considered untreatable in the past due to close proximity of vital organs and structures. Treating such tumors requires tremendous accuracy. For example, in the case of head and neck tumors, IMRT allows radiation to be delivered in a way that minimizes exposure to the spinal cord, optic nerves, salivary glands or other important structures. In the case of prostate cancer, exposure to the nearby bladder or rectum can be minimized.

High Dose Rate Brachytherapy (HDR)

HDR Brachytherapy is a form of internal radiation therapy that places the source of the high-energy x-rays as close as possible to the cancer cells so that fewer normal cells are exposed to radiation. By using HDR Brachytherapy, the doctor can give a higher total dose of radiation in a shorter time than is possible with external treatment. Instead of using a linear accelerator, the radioactive material is placed directly into the affected area. HDR Brachytherapy often is used for cancers of the breast, uterus, cervix and lung.

HDR Brachytherapy allows a person to be treated within a few minutes in inpatient or outpatient clinics. With remote HDR Brachytherapy, a very powerful radioactive source travels by remote control through tubes, or catheters, to the tumor location. The radioactivity remains at the tumor for only a few minutes. This procedure is done by the highly skilled radiation oncology team, who will watch you on a closed-circuit television. They can also talk to you through an intercom if needed. In some cases, several remote treatments may be required. Sometimes, the catheter stays in place between treatments and sometimes it is removed, depending on your condition.

High dose rate treatments are short (usually a few minutes) and result in less discomfort than other types of radiation therapy. Because radioactive materials are not left in your body, you can return home soon after you recover.


Breast conservation therapy (BCT) allows more and more women with early stage breast cancer the ability to treat their breast cancer effectively and preserve their breasts. BCT begins with a lumpectomy, the surgical removal of the cancerous tumor. The lumpectomy is generally followed by seven weeks of External Beam Radiation Therapy, during which radiation is directed at the whole breast. This combination of surgery and radiation works well to treat breast cancer. However, some women aren’t comfortable with the idea of radiation going through healthy breast tissue in order to treat the affected area.

One treatment option for patients undergoing breast conservation therapy is partial breast irradiation. The most widely practiced method of partial breast irradiation is breast brachytherapy. MammoSite is a form of partial breast irradiation.

Brachytherapy treats the breast using a radiation source that is placed inside the body. This has four important advantages:

  • Radiation is delivered from inside the breast directly to the area where cancer is most likely to recur
  • This limits the amount of radiation to healthy tissue, thereby reducing the potential for side effects.
  • Therapy can be completed in five days

MammoSite is a small, soft balloon attached to a thin catheter (tube) that fits inside the lumpectomy cavity (the space left after the tumor is removed). A tiny radioactive source (seed) is placed within the balloon by a computer-controlled machine.

Because the source is inside the balloon, radiation is delivered to the area of your breast where cancer is most likely to recur. When used as a primary therapy – the only form of radiation following a lumpectomy – you would receive treatments twice a day for five days.