Radiation Therapy Flashcards
What is radiation therapy, also known as?
Radiation therapy is also known as radiotherapy or X-ray therapy.
What does the term “radiation” mean in the context of radiation therapy?
In the context of radiation therapy, “radiation” means to give off energy as waves or particles.
What types of energy beams are commonly used in radiation therapy?
Common energy beams used in radiation therapy include x-rays, gamma rays, electron beams, protons, and neutrons.
What is ionizing radiation, and how does it affect atoms?
Ionizing radiation refers to particle beams that can remove tightly bound electrons from an atom’s orbit, causing the atom to become charged (ionized). The created ions are reactive and give off bursts of energy.
How does radiation therapy affect DNA in cells?
Radiation therapy causes small breaks in the DNA of targeted cells, making them especially vulnerable during replication.
Why are cancer cells more affected by radiation therapy than normal cells?
Cancer cells are more consistently replicating than normal tissue cells, making them more vulnerable to injury from radiation therapy.
What is the primary intent of radiation therapy?
The primary intent of radiation therapy is to damage the DNA of cancer cells so they become unable to reproduce.
How are radiation beams targeted in radiation therapy?
Radiation beams are very precisely targeted to maximize impact on cancerous tissues while minimizing damage to nearby normal cells.
How do normal healthy cells respond to radiation damage compared to cancerous cells?
Healthy normal cells are better able to correct damage or undergo apoptosis and can reconstitute themselves better than cancerous tissues, where the cells do not work together systematically.
What types of normal tissues are most affected by radiation therapy?
Normal tissues that are most affected include the skin, smaller bones, and permanent cell structures such as the heart and nervous system, especially with intense radiation protocols.
What is a potential long-term risk of radiation therapy?
There is a risk of developing a new cancer at the site of radiation therapy in 10-15 years.
How many cancer patients receive radiation therapy?
More than half of cancer patients receive radiation therapy, which is often localized rather than generalized.
What is one use of radiation therapy following surgery?
Radiation therapy is used to ‘clean up’ following surgery, specifically targeting the surgical field and nearby lymph nodes, especially when there are positive margins.
How can radiation therapy assist in making tumors more operable?
Radiation can shrink tumors by killing off part of their cell population, making them smaller and weakening their attachment to host tissues, which creates better conditions for surgical removal.
In what situations might radiation therapy be preferred to preserve structures?
Radiation may be preferentially used when surgery could potentially cause too much damage to critical structures, such as the larynx, brain, esophagus, or major blood vessels.
How does radiation therapy help manage inoperable tumors?
Radiation can slow the progression of inoperable tumors, giving the patient more time, assisting other cancer therapies, and helping reduce symptoms caused by the cancer (e.g., in bones, liver, brain).
When might radiation therapy be considered the most effective or safest choice?
Radiation therapy may be the most effective or safest choice for radiosensitive cancers (e.g., leukemia, lymphoma) or when tumors are located such that high-dose targeted radiation can be used without damaging major structures (e.g., testicular, prostate, cervix, limbs).
How can radiation therapy impact the use of chemotherapy?
The effective use of radiation therapy can mean that chemotherapy can be avoided or used more sparingly, as chemotherapy affects the whole body.
What is the purpose of radiation therapy in palliative care?
In palliative care, radiation therapy is used for the “relief of suffering,” such as radiating locations in the spinal cord to manage pain.
What are the three ways radiation therapy can be delivered?
Radiation therapy can be given through external beam radiation, internal radiation (brachytherapy), and systemic radiation. Substances may also be administered to increase radiosensitivity or protect normal cells.
What is the most commonly used delivery method for radiation therapy?
The most commonly used delivery method is External Beam Radiation.
How is the radiation area determined for external beam radiation?
The treatment area usually includes the whole tumor plus a small amount of normal tissue on all sides to account for microscopic local spread of undetectable cells. In postsurgical cases, the zone is typically the full surgical field and local lymphatics.
What is the common treatment protocol for external beam radiation?
The most common protocol is 5 days per week for 3-5 weeks, used following surgery and for tumor shrinkage. Other options, like once or twice per week, may be used for tumor management or palliation.
Why is it essential for patients to maintain the same position during radiation treatment?
It is essential to ensure accuracy in treatment delivery, accounting for factors like movement during breathing. Simulation sessions are used to get coordinates exactly right.
What aids are used to ensure patient immobility during radiation treatment?
Patients may be fitted for body molds, mesh masks, and other devices to ensure immobility during treatment.
How are beam coordinates often marked on patients’ skin?
The coordinates are commonly tattooed onto the patient’s skin using permanent dark blue markings that resemble small moles.
