The UC Davis Department of Radiation Oncology provides a number of unique treatment modalities for cancer. The faculty, physicians and physicists responsible for treatment programs and planning for individual patients are well published and experts in their fields.

Contents
Brachytherapy programs
Gamma Knife radiosurgery
Intensity modulated radiation therapy (IMRT)
Image guided radiotherapy (IGRT)
Stereotactic body radiation therapy (SBRT)
High dose rate (HDR) brachytherapy
Low dose rate (LDR) brachytherapy: prostate cancer*

Gamma Knife surgery is recognized worldwide as the preferred treatment for arteriovenous malformations, certain brain tumors, and brain dysfunctions such as trigeminal neuralgia. Over 2,500 peer-reviewed research articles primarily published in neurosurgery journals support its use. Since our Gamma Knife machine was commissioned in October 2003, the Department of Radiation Oncology at UC Davis has treated over 300 patients utilizing this state-of-the-art technology. 

For more information please see stereotactic surgery at the UC Davis Cancer Center.

IMRT is a new and advanced form of  radiation therapy that delivers  higher doses of radiation to the tumor and lower doses to nearby healthy tissue. With IMRT, your treatment plan may allow you to receive a higher dose of radiation each day, potentially shortening the overall treatment time and improving treatment success. Some patients also experience fewer side effects during IMRT than more conventional treatment.

The radiation is delivered by a linear accelerator equipped with a multileaf collimator which helps to shape or sculpt the beams of radiation. The machine producing radiation can be rotated around the patient so that beams can be delivered from the best angles. Carefully planned and precisely manipulated beams conform as closely as possible to the shape of the tumor. Although IMRT is being used to treat tumors in the brain, head and neck, nasopharynx, breast, liver, lung, prostate and uterus, this new technology is not always appropriate or necessary for every patient and/or type of cancer.

If you are a patient and have more questions about IMRT at UC Davis see our FAQS under IMRT or ask your radiation oncologist.

IGRT brings scanning and radiation equipment together to permit the doctor to see the area of the body almost simultaneously while treating. Combining imaging and treating equipment provides views of the patient's organs in the treatment position at the time of treatment.

Traditionally, patients receive radiotherapy five days a week for six to nine weeks. Prior to treatment, radiation oncologists do formal imaging called simulation, and plan where, how and with what doses to treat. In the past, after this planning session, we did not image everyday to know the status of the tumor or the position of the normal tissues. However, IGRT enables us to be more precise. With IGRT, more frequent imaging just prior to daily treatment enables us to determine the position of the tumor and the surrounding normal tissues just as they are at time of treatment. As more precise targeting becomes possible, we can deliver higher doses of radiation for better control of cancer and minimize the doses to critical normal tissues.

Stereotactic body radiation therapy (SBRT)  is a similar procedure to brain stereotactic radiosurgery and radiotherapy (see Gamma Knife), except it is used on tumors outside the brain (extracranial), generally in the lungs, liver and spine. Like radiosurgery, it is an ablative therapy, meaning it is given to fully eradicate the cancer cells. We use the new Elekta_S linear accelerator as it safely and effectively delivers highly focal radiation treatments to a larger target. SBRT involves anatomically accurate imaging and restriction of target motion, in other words, the ability to delivery highly precise, high dose radiation (either in a single dose or in a small number of high-dose fractions) to areas with substantial normal organ motion inside the body. With better target localization via image guided planning and delivery, and patient immobilization, more healthy tissue near the tumor is unharmed.

Our department offers HDR brachytherapy , a technically advanced form of cancer treatment, as an option to patients with gynecologic and other cancers (e.g., breast, head and neck, esophagus, lung, anorectal, bile duct or sarcoma). High-dose localized radiation is inserted temporarily, delivering the treatment quickly to the tumor and limiting the dose on adjacent body organs. HDR can often be done on an outpatient basis, and can reduce treatment time from six to eight weeks of daily external radiation therapy to as little as three to 10 days, depending on the type of cancer being treated. If patients also need chemotherapy, HDR brachytherapy allows them to start that treatment sooner, possibly improving their chances for a cure. Unlike low dose rate brachytherapy, physicians know what the final doses will be before any radiation treatment is given. Compared to conventional treatments, there can be fewer side effects as well.  After treatment, the radiation source is removed from the patient and the patient is no longer radioactive.

UC Davis is the only hospital in Sacramento offering HDR brachytherapy.  Call us to learn more at (916) 734-8252.

*Please note: The following discussion is included for educational purposes only as we do not yet offer brachytherapy for prostate cancer at UC Davis.

Brachytherapy, also called radioactive seed implant therapy, puts radiation right where the cancer is. The radioactive seeds are placed close to or directly in the tumor. Your radiation oncologist and urologist would work together to perform this procedure.

Up to 125 tiny radioactive seeds about the size of a sesame seed are implanted into the prostate. The radiation kills the cancer cells over a period of a few months. How long the seeds remain radioactive depends on the radioactive material used and its dose. The seeds can safely remain in the prostate for the rest of a person’s life. These seeds are so small that patients do not feel them. The radioactive isotopes used are iodine or palladium.

Because the seeds are so close to the cancer cells, the cancer cells get inundated with radiation while the rectum, bladder, penis and other tissues receive minimal radiation. With seeds, a higher equivalent radiation dose may be delivered to the prostate than with external beam radiation.

In contrast, other radiation therapy techniques, including conformal therapy, penetrate radiation from outside the body to the inside; thus, the radiation must first go through normal tissue before it reaches the prostate located deep inside the body. With seed implant treatment, radiation hits the prostate first, and only then strikes normal tissues, when the radiation has weakened.

Is seed implant therapy a new technique?  Why has it become more common in recent years?

Before computers enabled us to see inside the body, doctors could only estimate where a man’s prostate was and where the radioactive seeds should be implanted. Thus, early results with implant therapy were not good, and the approach was abandoned for years.  Now trans-rectal ultrasound (TRUS) enables us to view the prostate more clearly. Using ultrasound to see the prostate gland better, physicians can place each seed in the prostate more carefully. Excellent results are obtained by experienced physicians using ultrasound-guided radioactive implantation. Computed tomography is also used.

What is the downside to consider?

Using radioactive seed implants creates a dilemma.  Because vital structures in this area of the body are so close to each other, it is difficult to affect one part without also affecting neighboring structures.

Imagine the prostate, rectum and bladder as three rooms next to each other, with a common wall between them.  To treat cancer in the prostate one has to put the seeds very close to the wall between the rectum and prostate, and the wall between the prostate and bladder. If the seeds are not close to these walls, the cancer may not be adequately treated. If the seeds are too close to these walls, the rectum or bladder may receive high doses of radiation.

Seed implantation is a type of surgery.  Needles are inserted into the prostate through the patient’s perineum between the scrotum and anus. Therefore, the results depend upon the experience and skill of the operators,  the radiation oncologist and urologist. This is considered minor surgery as it mostly uses local or regional anesthesia athough sometimes general anesthesia is used. It is usually performed as a one day, outpatient procedure, with little disruption of normal work or other activities and a short recovery time.

Like conformal radiation therapy, the modern ultrasound-guided implant therapy is new, and practitioners are still learning or perfecting their techniques. Long-term results are not yet available at many institutions. However, numerous studies have shown that five-year recurrence-free survival rates with brachytherapy are the same as with radical prostatectomy or external beam radiation. This makes selecting a treatment a difficult and personal choice.

What are the side effects of brachytherapy?

• Fatigue after the procedure.
• Temporary need for distance from children and pregnant women — because you are mildly radioactive, you will need to avoid being close to children and pregnant women for a few weeks.  Although the seeds continue to emit radiation for some time, most of the dose is absorbed by the surrounding tissue and very little penetrates the body. 
• Temporary urinary symptoms immediately after implantation.
• Impotence in up to half of men treated — this occurs gradually. The incidence is less than with either radical prostatectomy or external beam radiation therapy. Products such as Viagra can help treat this.  How potent a patient is before the treatment affects potency afterwards.
• Bowel problems, such as diarrhea, cramps, rectal pain and burning, sometimes occur immediately after the procedure. However, severe bowel problems are rare and occur less frequently than with external beam radiation. Up to five percent of patients may have more permanent bowel side effects (burning, pain and diarrhea).
• Catheterization for about 10 percent to 15 percent of patients after the procedure.

How will I know if the brachytherapy is working?

Your doctor will monitor your prostate specific antigen (PSA) levels, which should reach their low point and stay there.  If your PSA has three consecutive rises over an 18-month period, that is considered treatment failure, the same as it is with external beam radiation therapy.  This definition of PSA progression is from the American Society of Therapeutic Radiology and Oncology (ASTRO).

Another definition of treatment failure may be applied to your treatment: a PSA-based definition of treatment failure, rather than just tracking PSA rises.  Waiting for three rising PSA values may be too stringent when two large consecutive rises clearly indicate treatment failure or when the interval between determinations is long.  This low-point definition correlates more closely with clinical outcomes than the standard ASTRO definition..