Understanding Radiation Therapy Le By i f A

Understanding Radiation Therapy Le By i f A d e m a h o e c M n e i c Dr: S l a c i g o l o di a R r e r ctu

Introduction to Radiation Oncology Ø Radiation has been an effective tool for treating cancer for more than 100 years. Ø About two-thirds of all cancer patients will receive radiation therapy as part of their treatment.

What Is Radiation Therapy? Ø Radiation therapy works by damaging the DNA within cancer cells and destroying their ability to reproduce. Ø When the damaged cancer cells are destroyed by radiation, the body naturally eliminates them.

Ø Normal cells can be affected by radiation, but they are able to repair themselves. Ø Sometimes radiation therapy is the only treatment a patient needs. Ø Other times, it is combined with other treatments, like surgery and chemotherapy.

Methods of Delivering Radiation Therapy Early 1950 s Today

How Is Radiation Therapy Used? Radiation therapy is used two different ways. q. To cure cancer: Ø Destroy tumors that have not spread to other body parts. Ø Reduce the risk that cancer will return after surgery or chemotherapy.

q. To reduce symptoms: ØShrink tumors affecting quality of life, like a lung tumor that is causing shortness of breath. ØAlleviate pain by reducing the size of a tumor.

Types of Radiation Therapy q Radiation therapy can be delivered two ways: v External beam radiation therapy Ø delivers radiation using a linear accelerator.

v. Internal radiation therapy, called brachytherapy, involves placing radioactive sources inside the patient. Ø The type of treatment used will depend on the location, size and type of cancer.

Planning Radiation Therapy Simulation q Each treatment is mapped out in detail using treatment planning software. q Doctors use several devices to do this: Ø Skin markings or tattoos. Ø Immobilization devices – casts, molds, headrests.

External Radiation Therapy q. Specialized types of external beam radiation therapy ØThree-dimensional conformal radiation therapy (3 D-CRT) § Uses CT or MRI scans to create a 3 -D picture of the tumor. ØIntensity modulated radiation therapy (IMRT) • Radiation is broken into many “beamlets” and the intensity of each can be adjusted individually.

External Radiation Therapy Techniques q. Proton Beam Therapy ØUses protons rather than X-rays to treat certain types of cancer. q. Neutron Beam Therapy ØA specialized form of radiation therapy that can be used to treat certain tumors that are very difficult to kill using conventional radiation therapy. q. Stereotactic Radiotherapy Øallows the radiation oncologist to precisely focus beams of radiation to destroy certain tumors, sometimes in only one treatment.

Internal Radiation Therapy q. Places radioactive material into tumor or surrounding tissue. Ø called brachytherapy Ø Radiation sources placed close to the tumor so large doses can hit the cancer cells. Ø Allows minimal radiation exposure to normal tissue. Ø Radioactive sources used are thin wires, ribbons, capsules or seeds.

Side Effects of Radiation Therapy Ø Side effects, like skin tenderness, are generally limited to the area receiving radiation.

Gamma interaction with matter q. Radiation treatment is based on different kind of radiation and depends on the different kind of interaction between the radiation and matter (body tissue).

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