Cancer Treatment Modalities: Radiation Flashcards
Radiation therapy =
The medical use of ionizing radiation (IR) as part of cancer treatment to control malignant cells
How does RT kill cancer cells?
By damaging their DNA directly or create charged particles (free radicals) within the cells that can also damage -> stops cancer division, causing cell death
Classes of RT (3)
External beam RT Internal RT (brachytherapy) Systemic RT (radioactive iodine travels in blood to kill cancer cells)
Goals of RT can be (3)
1) Curative
2) Control
(even when CT/MRI show no tumors, used prophylactically for some types of cancer ex) brain radiation fro lung CA)
3) Palliative
(to relieve sx of pain, mobility, ability to eat/drink such as brain mets, spine mets, tumor near esophagus)
External beam RT is most _____, generated by a ____ _____ (a machine that accelerates electrons to produce x-rays or gamma rays)
Common
Linear accelerator
A form of EBRT that uses cyclotrons or synchrotrons to produce charged atoms that destroy tumors
Proton therapy
A type or radiation therapy common for tx or prostate, uterus, cervical, breast CA
Brachytherapy
Type of radiation that is put inside the pt, sealed in needles, seeds, wires, catheters, or implanted directly into or near a tumor
Brachytherapy
Cancers only treated with radiation and not chemo (2)
Prostate
Larynx
Radiation used after surgery =
Adjuvant RT
Radiation used before surgery
Neoadjuvant or induction RT
Combined modality therapy
Chemo and RT used simultaneously without surgery
An advanced form of three dimensional (3D) conformal radiation that precisely conforms the dose to tumors, allows safer delivery of higher than conventional doses
Intensity modulated RT (IMRT)
Intensity modulated RT commonly combined with what type of RT?
Image guided RT (IGRT)
RT that used 3D imaging to determine exact coordinates of tumor
Stereotactic radiosurgery
Ex) Gamma knife (uses radioactive cobalt sources to focus multiple beams of RT on a small area)
Radiation used to cut off blood flow to a tumor in vascular organs -> starvation
Radioembolization
The basic unit of light and other forms of electromagnetic radiation
Photon
EBRT is often delivered in _____
Photons
1) X rays
2) Gamma rays
Which type of photon has higher energy? Gamma rays or x rays
Gamma rays have the highest energy, followed by photons in x rays
Commonly used machine that delivers EBRT
Linear Accelerator (LINAC)
One of the most common types of EBRT that uses very sophisticated computer software and advanced treatment machines to deliver radiation to very precisely shaped targets
3D conformal RT (3D-CRT)
A type of 3D RT that reduces damage to healthy tissues
IMRT (intensity modulated RT)
Tomotherapy
A type of IMRT
(Helical tomotherapy)
RT aimed at tumor from many diff directions (pt put through a donut shaped machine)
Type of external RT that uses special equipment to position pt and precisely give a single large dose of radiation to a tumor (often used to treat brain tumors)
Stereotactic radiosurgery
Type of external RT that uses special equipment to position a pt and precisely deliver radiation to tumors in the body (except in brain)
Stereotactic body radiation therapy (SBRT)
Type of RT that uses streams of protons to kill tumor cells
Diff than X-ray radiation
Reduces amount of radiation damage to health tissue near tumor
Tx for head and neck, brain, eye, lung, spine, prostate
Proton therapy
Type of beams used to irradiate superficial tumors, such as skin cancer or tumors near surface of body - cannot travel far in tissue
Electron beams
Radioactive iodine (oral cocktail) classifies as what type of radiation?
Tx of what type of CA?
Systemic RT
Thyroid - thyroid cells naturally take up radioactive iodine
Ibritumomab tiuxetan (Zevalin) is a monoclonal antibody that classifies as what type of RT?
How does it work?
Tx for what type of CA?
Systemic RT
The antibody joined to the radioactive substance travels through blood, locating and killin tumor cells
B cell non-Hodgkin Lymphoma (NHL) - the antibody binds to protein found on surface of B lymphocytes
Samarium 153 Lexidronam (Quadramet)
And Strontium-89 chloride (Metastron) are examples of what type of radiation?
Used to treat what?
Radiopharmaceuticals (Systemic radiation)
Pain from bone Mets
Acute SE of Radiation
Think of damage to rapidly dividing normal cells
Skin irritation
Damage to salivary glands
Hair loss
Urinary or bowel problems
Only FDA approved drug that helps protect salivary glands from radiation damage =
Amifostine (Ethyol)
Systemic SE of Radiation
Fatigue
N/V
Ibritumomab tiuxetan (Zevalin) is a monoclonal antibody that classifies as what type of RT?
How does it work?
Tx for what type of CA?
Systemic RT
The antibody joined to the radioactive substance travels through blood, locating and killin tumor cells
B Lymphocytes
Samarium 153 Lexidronam (Quadramet)
And Strontium-89 chloride (Metastron) are examples of what type of radiation?
Used to treat what?
Radiopharmaceuticals (Systemic radiation)
Pain from bone Mets
Acute SE of Radiation
Think of damage to rapidly dividing normal cells
Skin irritation
Damage to salivary glands
Hair loss
Urinary or bowel problems
A radioprotector that is the only FDA approved drug that helps protect salivary glands from radiation damage =
Amifostine (Ethyol)
Late SE of Radiation
Fibrosis (replacement of normal tissue w scar tissue -> restricts movement of affected area)
Damage to bowels -> diarrhea or bleeding
Memory Loss
Infertility
Secondary cancer (rare)
Radiation safety Acronym
ALARA
ALARA means
As low as reasonably achievable
3 main principles of radiation safety
Time
Distance
Shielding
Education points for pts receiving Brain radiation
Short term SE -> hair loss, n/v, hearing loss, scalp changes, trouble w memory and speech, seizures
Advise pts to only to only use recommended moisturizers and shampoos to decrease irritation
Use sunscreen to protect scalp
Pt education points for those receiving breast radiation
Avoid bras with underwire, nylon, or lace
Wear breathable cotton bra
Can use deodorant but
Don’t shave armpits to prevent skin irritation
Pt education points for those receiving head or neck radiation
Dry mouth -> suggest oral mouthwash
Advise pt to see dentist before RT to check for decayed teeth or oral infection
Pt education for those receiving pelvic radiation
For young male and female pts, provide info about sexuality and possible infertility before RT
Banking sperm, egg harvesting options
Symptom management for RT SE
1) Fatigue
2) Anorexia
3) Mucositis
4) Xerostomia (dry mouth)
5) Alopecia
6) N/V
7) Bone marrow suppresssion
1) encourage pt to prioritize and delegate responsibilities, gentle exercise
2) eat small, frequent meals, appetite stimulant, eat nutritious high protein snacks, avoid fat and grease, take nutritional supplements
3) Avoid oral irritants -> alcohol, tobacco, spicy, acidic food, hot drinks. Eat soft or liquid diet. Oral care w saline or water frequently
4) Moisten foods, use artificial saliva, avoid dry foods, soak foods in coffee, milk, warm drinks
5) Gently brush, decrease frequency of shampoo, avoid hair dye, chemicals, psych support -> wig?
6) small frequent meals, drinking clear cold drinks, avoid overly sweet, greasy, high fat foods. Elevate HOB, Antiemetics
7) weekly blood count monitoring, educate pt to observe s/s of bleeding and infection, let them know blood transfusions might be necessary
Type of radiation that uses a computer to create a picture of a tumor to help guide the radiation beam during RT
Pictures made using CT, US, Xray
Also more accurate and less damage to healthy tissue
IGRT (Image guided radiation therapy)
Type of radiation where radiation materials are placed inside the body =
Brachytherapy
Type of brachytherapy where the radiation source is placed within tumor tissue =
Interstitial brachytherapy
ex) prostate tumor
Type of brachytherapy where source is placed within a surgical cavity, or body cavity =
Intracavitary brachytherapy
Type of brachytherapy used to treat melanoma inside the eye (attaches to the eye) =
Episcleral brachytherapy
Brachytherapy uses radioactive _______ that are sealed into tiny pellets or _____.
How do the isotopes work?
How is it inserted into the patient?
Isotopes, seeds
Isotopes naturally decay, so give off radiation that damages nearby cancer cells
Catheters, needs, etc
What happens if you leave the isotopes in the body?
They decay completely and no longer give off radiation -> not harmful if left in body
Brachytherapy
1) Low dose rate =
2) High dose rate =
1) cancer cells receive continuous low dose radiation from the source over a few days
2) robotic machine attached to delivery tubes placed inside body guides radioactive sources into or near tumor, then removes the sources at end of treatment session
Mammosite =
Type of intracavity brachytherapy used for Breast CA after lumpectomy, small balloon filled with liquid and left in place, catheter places radioactive seeds into balloon twice a day for 5 days then removed each time (balloon catheter radiation)
Type of radiation where pt swallows or receives injection of radioactive substance such as radioactive iodine or radioactive substance bound to monoclonal antibody =
Systemic Radiation Therapy
