Radiation oncology, or radiation therapy as
it is sometimes called, may be used as the primary
treatment for malignancies, or it may be administered
in conjunction with chemotherapy or surgery.
It is administered either externally or internally.
External beam radiation is similar to the X-rays, but are of higher energy and higher doses. Radiation treatments are usually given daily, Monday through Friday, over several weeks so that side effects are minimized and normal tissues exposed to radiation are allowed to recover. As with X-rays, the patient has no sensation when receiving radiation.
Radioactive implants can be surgically placed near or in the area of the cancerous growth. Most implants are removed after a few days, but some implants remain permanently to destroy tumors deep within the body, such as those used for prostate cancers.
Radiation therapy may have side effects, depending on the area being treated and the total dosage prescribed. Side effects can usually be controlled or minimized through medication or modification of the treatment method. If radiation therapy is recommended, a radiation oncologist will discuss the possible side effects of the treatment program and how to overcome them successfully.
Working in conjunction with a multidisciplinary
team specializing in cancer, John
a radiation oncologist, provides treatment of
malignancies with high energy x-rays, electrons,
or radioactive isotopes. Treatment planning begins
with imaging done on a CT
(computerized tomographic) virtual simulator.
This dedicated machine facilitates the accurate
delineation of the tumor and normal tissue structures,
enhancing the individualized plan of care. Actual
treatments are delivered on the linear accelerator
best suited to treat a particular tumor site.
The Varian 2100 linear accelerator has 6 and 18 MV photons and electron energies ranging from 6 MeV to 18 MeV. High-energy photons are appropriate for deep-seeded malignancies, while electrons are useful for more superficial malignant disease. The Siemens Oncor linear accelerator has 6 and 10 MV photons and electron energies ranging from 6 MeV to 21 MeV.
It has the added capability of delivering Intensity Modulated Radiation Therapy (IMRT). With IMRT, normal tissues are protected, not with customized lead alloy shields, but through the dynamic use of multileaf collimators (1 cm square metal strips). Computerized instructions to the collimators direct high, homogenous doses to tumors, while sparing normal tissue. The combination of CT planning with 3-D radiation and IMRT should further reduce any side effects experienced by patients.
The staff continues to use brachytherapy for
prostate, soft tissue tumors and gynecologic
tumors. For the treatment of breast cancer, Mammosite® may be an option for select patients. Non-oncologic
diagnoses treated with radiation include Grave's
disease, heterotopic bone formation, keloids and cardiac instent restenosis.
The Department of Radiation Oncology participates in national cooperative trial studies with the Gynecologic Oncology Group (GOG), the Eastern Cooperative Oncology Group (ECOG), and the Radiation Therapy Oncology Group (RTOG) through the Abramson Cancer Center of the University of Pennsylvania.