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Radiation Oncology Clinic

Overlake Radiation Oncology is an outpatient clinic offering advanced radiation treatment in a comfortable setting close to home for those on the Eastside. Our specially trained radiation oncologists— Dr. James G. Pelton and Dr. William Brent Reece—develop treatment plans and direct patient care.

What is Radiation Therapy?

Radiation therapy destroys or damages cancer cells by using powerful, targeted X-rays or gamma rays. Because these high-energy rays can be directed to many parts of the body, radiation therapy is used in nearly half of all cancer cases. Radiation therapy may be used alone or combined with surgery or chemotherapy, depending on your individual treatment plan. For most patients, radiation therapy is given five days a week for five to seven weeks.

Advanced Radiation Technologies

Overlake uses highly sophisticated radiation technologies that enable patients to receive faster, more precise treatments with fewer side effects. Radiation therapy is comprised of two treatment types: external and internal radiation.

External Therapies

External Beam Radiation Therapy

External beam radiation, the most common type of therapy, destroys cancer cells with high-energy ionizing radiation. Delivering the strongest dose of radiation possible, this state-of-the art treatment uses pinpoint accuracy to maximize dosage to the cancer, while minimizing damage to surrounding areas. Used to treat many types of malignancies, this treatment is painless and carried out over several weeks.

Stereotactic Radiosurgery (SRS)

SRS delivers large radiation doses to tumors in a single session, or up to five treatment sessions.  The goal of this non-invasive procedure is to destroy or shrink the tumor without harming nearby healthy tissue and without requiring traditional surgery.

Intensity Modulated Radiation Therapy (IMRT)

IMRT, one of the breakthrough achievements in radiation therapy, is used for diseases in which the tumor is close to sensitive areas, such as the bladder or nerves. Combined with Multi-Leaf Collimation (MLC), which uses a series of leaf-like structures to block radiation from healthy tissue, IMRT can be used on virtually any tumor site to protect normal tissue.

3-D Conformal

This approach uses a computer to generate a 3-D image of the tumor, allowing the radiation team to clearly see which areas will be affected by the proposed dose and to what extent (where the radiation beam enters the body, what it passes through and where it leaves the body). This targets the tumor and avoids contact with healthy tissues and organs.

Image Guided Radiation Therapy (IGRT)

Image Guided Radiation Therapy combines imaging and treatment on a single, fully robotic machine to more effectively pinpoint cancer tissue. Knowing the exact location of the tumor allows the radiation oncologist to target only the tumor, thereby sparing the surrounding, healthy tissue.

Internal Therapies


Brachytherapy is an internal radiation treatment that involves implanting radioactive isotopes, or "seeds," into the body near the tumor. These radiation sources can be removed following treatment or, in some cases, may remain in the body. Radioactive implants are used to treat a wide range of malignancies including prostate, breast, lung and cervical cancer.

Prostate Radioactive Seed Implant

Prostate radioactive seed implant is an option that can be offered to many men with early-stage prostate cancer. Overlake's team of urologists, radiation oncologists, physicists, dosimetrists and nurses all work closely in providing this highly successful treatment.


MammoSite is a leading-edge treatment offering many advantages for women diagnosed with early-stage breast cancer. It uses a tiny device that is placed inside the breast where it delivers high doses of radiation to the area where cancer is most likely to recur. Traditional radiation therapy requires six weeks of treatment, while MammoSite can be completed in just five days. And since radiation is delivered from within the breast, it limits the amount of radiation to healthy tissue and reduces possible side effects.

Expert Care and Support

Our philosophy at Overlake Radiation Oncology is to provide treatment in an environment that supports and promotes the highest quality of life, sensitive to your individual physical, psychological and educational needs. Our broad range of care for patients, families and the community includes advanced cancer treatments, as well as support groups, nutritional counseling services, social services, oncology-certified nursing care and an educational resource room.

Our Radiation Oncologists

James Pelton, MD, Brent Reece, MD

Dr. James Pelton
Dr. William Reece

Overlake Radiation Oncology is located in Suite 160 of the Overlake Medical Tower. For more info, contact us at 425-688-5289.

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