Types of Radiation Therapy
Radiation is given either externally, through external beam radiation, or increasingly through internal radiation, also called brachytherapy. Like surgery, radiation therapy is a local treatment; it affects cancer cells only in the treated area. Radiation can come from a machine (external radiation). It can also come from an implant (a small container of radioactive material) placed directly into or near the tumor (internal radiation). Some patients receive both kinds of radiation therapy.
External Radiation Therapy
External beam radiation therapy is administered just like a normal X-ray. The radiation used for external beam radiation treatments comes from special machines, such as linear accelerators, cobalt machines, or orthovoltage x-ray machines. They deliver intense treatments with pinpoint accuracy. External radiation therapy is usually given on an outpatient basis in a hospital or clinic 5 days a week for a number of weeks. Patients are not radioactive during or after the treatment.
External Beam Radiation Therapy Treatment
|Type of Radiation||Area of Maximum Dose||Indications|
Skin surface (higher than bone absorption)
|Superficial skin lesions
|Gamma Ray Therapy
(cobalt or cesium)
|0.5 cm below skin surface||Most malignant conditions|
(x-rays or electrons)
6 MV machines
15 MV machines
|1.5 cm below skin surface
3.0 cm below skin surface
|Most malignant conditions especially if deep seated in the body|
|Particle beam therapy
(neutron beam therapy)
|Increased uptake in fatty tissue||Late stage malignant disease, tumors that are large, anoxic, necrotic, and resistant to treatment|
Source: Brunner and Suddarth’s Medical-Surgical Nursing by Smeltzer and Bane
Internal Radiation Therapy
Internal radiation therapy involves placing radioactive substances such as cesium, iridium, and iodine near or into cancerous cells within the body. Patients usually remain in the hospital for at least one day. Because the level of radiation is highest during the hospital stay, patients may not be able to have visitors or may have visitors only for a short time. Once an implant is removed, there is no radioactivity in the body. The amount of radiation in a permanent implant goes down to a safe level before the patient leaves the hospital.
Internal Radiation can be implanted by way of:
- Catheters into body cavities or interstitial compartments
Implants may be permanent or temporary. Implants can be placed:
- Within the tumor within a body cavity such as the abdomen, called intracavitary
- Directly into the cancerous area, called interstitial
- By mouth or by injection
Types of Implants in Internal Radiation
- Intracavitary Radioisotope – this is frequently used in gynecologic malignancies. These isotopes are in placed for a prescribed period of time and then are removed.
Nursing care and management when a patient is implanted with intracavitary radioisotope:
- The patient should be maintained on bed rest.
- To prevent the displacement of the implant, logroll the patient when transfer or moving is necessary.
- To ensure that the urinary bladder is empty, an indwelling catheter should be inserted.
- To prevent the isotopes from being dislodged, bowel movements should be avoided. Low residue diets and administration of antidiarrheal agents such as Lomotil will prevent bowel movement.
- Interstitial implants – these implants may be temporary or permanent depending on the type of radioisotopes that are used. Usually this type of implant is composed of seeds, needles, wires or small catheters positioned to provide a local radium source and are less frequently dislodged.
Nursing care and management when a patient is implanted with interstitial implants:
- The nurse should keep in mind that patients with internal radiation emit radiation while the implant is in place. Thus, principles of time, distance and shielding should be implemented while caring for the patient.
- Distance: a distance of at least 3 feet should be maintained when the nurse is not performing nursing procedures.
- Time: contact should be limited to for 5 minutes each time, a total of 30 minutes per shift.
- Shielding: lead shield should be used during client contact.
- Minimize the exposure of the personnel to radiation.
- Assign the patient to a private room.
- Provide appropriate notices about radiation safety precautions.
- Make sure that the staff members are wearing dosimeter badges.
- Pregnant staff should NEVER be assigned to this patient.
- Visits by children or pregnant visitors are prohibited.
- Visits should be limited to 30 minutes per day.
- Make sure that the visitors maintain a 6 foot distance from the isotope source.