Radiation safety considerations with therapeutic 90Y Zevalin

ABSTRACT Radioimmunotherapy with the 90Y-labeled Zevalin radioimmunoconjugate is a new and promising modality in cancer treatment that combines the targeting power of monoclonal antibodies with the cytotoxicity of localized radiation. 90Y is a pure beta emitter, with different physical characteristics than traditional therapeutic radionuclides such as 131I. It is important that radiation safety professionals understand the characteristics of this radionuclide so that effective radiation safety procedures can be implemented with the Zevalin regimen. Because 90Y is a pure beta emitter, the Zevalin regimen is routinely administered as an outpatient procedure and is administered by using plastic shielding. Once the radioimmunoconjugate has been administered, the risk of radiation exposure to healthcare workers and family members is minimal. The primary route of biologic elimination of 90Y Zevalin is through the urinary system, with approximately 7% of the total activity administered eliminated over the course of 1 wk. Standard universal precautions, which should already be in place in healthcare facilities, should be sufficient to prevent radiation exposure to personnel working with patients who have been treated with Zevalin. Written radiation safety instructions for patients are not required, but basic instructions to the patient and his or her family may help further minimize the risk of radiation exposure and help alleviate patient and family concerns.