How Radiation Therapy is Administered to Patients
Radiation therapy involves the use of ionizing radiation to treat various malignant cancers and certain benign conditions. There are a variety of conditions and cancers that can be treated with radiation therapy.
Because cancer treatment can be complex and at times feel overwhelming, understanding the different types of radiation therapy can be helpful before beginning an individualized course of treatment. There are multiple types of radiation therapy, including:
- External beam radiation therapy
- Internal radiation therapy
- Systemic radiation therapy
- Intracoronary radiation therapy
External beam radiation therapy
External beam radiation therapy is the most common type of radiation therapy, in which invisible beams are delivered from outside the body to kill tumors and malignant cells. External beam radiation therapy involves the use of ionizing radiation, including photons (X-rays), gamma rays or protons (charged particles).
There are several types and delivery methods:
- Conventional radiation therapy is used to treat many cancers and can usually be started sooner than other treatment techniques. After an initial course of conventional radiation therapy, additional “boosts” may be given to a smaller treatment area.
- Electron beams are used to treat superficial tumors such as skin cancers or other tumors near the surface of the body.
- 3-D conformal radiation therapy allows treatment teams to visualize a patient’s anatomy in 3-D using specialized software that matches radiation doses to the size and shape of a tumor and thereby minimizes exposure to nearby tissues and organs. Scripps uses industry-leading equipment from Varian.
- Intensity modulated radiation therapy (IMRT) is an advanced form of 3-D conformal radiation therapy used most often to treat tumors near critical organs and sensitive regions such as areas of the prostate, as well as the head and neck. Scripps uses industry-leading IMRT systems, including TrueBeam, from Varian.
- Image-guided radiation therapy (IGRT) uses real-time imaging to ensure that any patient movement is accounted for during treatment for cancers in the body where motion occurs continuously (such as the lungs) when doses are delivered. Scripps radiation therapy equipment includes image-guided capabilities.
- Stereotactic radiosurgery (SRS) is delivery of a single high-dose in an extremely precise volume to minimize exposure to healthy tissues surrounding the cancer. SRS is used to treat lesions and brain tumors. It can be delivered through a Linear accelerator-based system (LINAC), a CyberKnife system (robotic frameless SRS with real-time tracking) or a Gamma Knife system (frame-based SRS used for brain tumors). Scripps uses leading-edge SRS equipment including systems from global leader, Varian.
- Stereotactic body radiation therapy/stereotactic ablative radiotherapy (SBRT/SABR) is used to treat tumors in nearly any part of the body, including the lungs, spine and prostate — and most often in two to five treatments. The number of treatments varies by site, size and location. SBRT/SABR can be delivered through a Linear accelerator-based system (LINAC), or a CyberKnife system (robotic frameless SBRT/SABR with real-time tracking).
- Total body irradiation (TBI) is a radiation therapy technique to treat the whole body at once and is an essential part of bone marrow or stem cell transplant treatment for cancers of the blood (leukemia) and some types of lymphoma.
- Proton therapy uses charged particles (protons) to kill tumors and cells of many types of adult and pediatric cancers with unprecedented accuracy. Scripps uses a ProBeam system featuring pencil-beam technology from Varian.
- Gamma Knife is a proprietary form of SRS to treat malignant and benign tumors of the brain with a single dose through the use of gamma rays. Despite its name, no surgical incision is required. The treatment is often recommended for patients who are not candidates for surgery or who want a non-invasive option to surgery. Scripps has a partnership with the San Diego Gamma Knife Center, which uses advanced equipment from Elekta.
- CyberKnife is a robotic frameless proprietary type of SRS/SBRT leveraging image-guided technology and is used to treat cancerous and non-cancerous tumors nearly anywhere in the body, including the prostate, lungs, brain, spine, liver, pancreas and kidneys. Cyberknife uses real-time tumor tracking during treatment to maximize accurate treatment delivery. Scripps uses leading-edge equipment from Accuray.
- Intraoperative electron radiation therapy (IOERT) is a mobile self-shielded, LINAC-based system used to treat breast cancer patients during surgery with a single dose that reduces the number of radiation therapy treatments post-surgery. Scripps is the first in San Diego to introduce this treatment and uses a Mobetron system from IntraOp.
- AccuBoost is a non-invasive form of accelerated partial breast irradiation (APBI) that is used as part of a breast conservation treatment approach following surgery.
Internal radiation therapy
- Brachytherapy is an internal form of radiation therapy in which radioactive substances are either temporarily or permanently placed inside the body near a cancer. Special radioactive seeds are designed to treat tumors and cancer cells at the source. It is primarily used for treatment of prostate cancer and breast cancer.
- SAVI is a brachytherapy delivery system for breast-conservation treatment.
Systemic radiation therapy
- Radioactive iodine is a systemic radiation therapy administered following surgery for thyroid cancer to eliminate any remaining cancer cells invisible to the human eye. It can also be used to treat a non-cancerous condition known as hyperthyroidism where the thyroid produces too much thyroid hormone.
Intracoronary radiation therapy
- Endovascular brachytherapy is a specific heart treatment for in-stent restenosis, a condition in which an artery that had been narrowed or blocked and was opened up with the placement of a stent has become narrowed again.
- Novoste Sr90 Beta-Cath System is a brachytherapy system for treating in-stent restenosis.