Safety Is Key in Use of Radiopharmaceuticals
Radiopharmaceuticals, or radioactive drugs, are playing an increasing role in cancer diagnosis and treatment and thus are an increasingly relevant area of practice for oncology nurses, Paul Searfoss, BS, CNMT, ARRT (N, CT), of Vanderbilt Medical Center in Nashville, TN, said during a session on Saturday, April 13, 2019, at the ONS 44th Annual Congress in Anaheim, CA (https://congress.ons.org/).
Searfoss provided a comprehensive overview of the process of administering a range of radiopharmaceuticals, including patient preparation prior to procedures and necessary post-treatment precautions to prevent exposure to or contamination from radioactivity. Nursing staff involved in a patient’s care must be trained in radiation safety prior to the patient’s admission, he said.
Oncology nurses will encounter three basic types of radiopharmaceuticals:
- Alpha radiation (e.g., radium-223) consists of heavy, short-range particles. It is used in treatment because of its ability to destroy cells.
- Beta radiation (e.g., yttrium-90) consists of light, short-range particles. Like alpha radiation, beta radiation is used in treatment.
- Gamma radiation (e.g., technetium-99m, thalium-201, xenon-133) is highly penetrating and is used for diagnostic imaging.
Patient preparation for studies or treatment involving radiopharmaceuticals varies with the drug being used. For example, for fluorodeoxyglucose studies to diagnose, stage, or evaluate the progression of cancer, patients must do no strenuous exercise for 24 hours and take nothing by mouth and no insulin injections for four to six hours prior to the study.
Patients receiving iodine-131 treatment for thyroid cancer must consume a low-iodine diet for at least one week and nothing but clear liquids for four hours prior to the procedure. Women of child-bearing age should have a negative pregnancy test within 24 hours before therapy. Pregnancy is a contraindication to iodine-131 treatment. Women who are breastfeeding should discontinue doing so two weeks before treatment.
Yttrium-90 microspheres are used to treat unresectable malignant hepatic neoplasms and are classified into two types: sirspheres (composed of biocompatible resin) and theraspheres (glass particles). Radiation safety personnel must be involved in the administration of microspheres because of the serious contamination hazard they present.
The safe use of radiopharmaceuticals is based on the As Low As Reasonably Achievable (ALARA) principle. Other general guidelines for controlling exposure to radioactivity are minimizing exposure time, maximizing distance from the radiation source, and using shielding to provide protection from the radiation source.
Patients and their family members should receive simple, clear written instructions on minimizing radiation exposure to other individuals after treatment. For example, patients receiving iodine-131 treatment should be aware that for several days after treatment their urine will be radioactive and they should avoid contact with small children, among other precautions.
The level of post-treatment precautions required varies depending on the radiopharmaceutical’s pattern of elimination from the body. Iodine-131 is eliminated via the salivary and sweat glands as well as the kidneys, necessitating extensive post-treatment precautions. By contrast, radium-223 is eliminated in urine and feces, so post-treatment adherence to good personal hygiene practices (e.g., showering daily, washing hands frequently) should be sufficient to prevent exposure.