Yttrium, Radioactive

Laboratory

A) Monitor vital signs and repeat every 2 hours for symptomatic patients.
B) Obtain a baseline CBC with differential and absolute lymphocyte count, then every 4 hours for the first 8 hours, then every 6 hours for the subsequent 40 to 48 hours, then daily. Lymphocyte kinetics and neutrophil/lymphocyte ratio are sensitive indicators of radiation dose.
C) Monitor for presence of sepsis or opportunistic infections, particularly in the presence of bone marrow depression and loss of intestinal mucosa.
D) A baseline serum amylase level should be obtained to evaluate for parotitis; repeat in 24 hours. Exposures above 0.5 Gy (50 rads) will result in a significant elevation of serum amylase. Electrolyte levels should be obtained when necessary.
E) Obtain blood and tissue typing, if the examination suggests a high-dose exposure. These patients may need bone marrow, umbilical cord blood, or peripheral stem cells due to pancytopenia.
F) If the history indicated possible inhalation or ingestion of radioactive materials, a 24-hour urine collection should be obtained for analysis, using any properly labeled sealed container. In addition, if inhalation may have occurred, nasal swabs should be obtained from each nostril, the amount of radiation in each should be measured with a handheld counter, and the 2 counts should be added. This amount divided by 0.1 provides a useful approximation of the inhaled dose, and this result can be compared with available tables that indicate the Annual Limit on Intake to determine if treatment is required (www.orise.orau.gov/reacts).
G) Cytogenetic dosimetry, the gold standard method of measurement, should be ordered and obtained after 24 hours to determine the actual dose absorbed by the patient. However, there are only 2 laboratories in the United States that perform cytogenetic dosimetry and results are not available for a few days.
H) Monitor for neurological symptoms, including a steadily deteriorating state of consciousness with coma and/or seizures during the neurovascular syndrome following very high acute radiation doses.
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