But Guskova’s decades of work in radiation pathology had helped her pioneer a method of biological dosimetry, gauging exposure based on interviews and tests. These included the time taken for the initial onset of vomiting and a count of white blood cells, or leukocytes. Manufactured in the bone marrow, these cells are the foundation of the body’s immune system and among the most reliable biological markers of the effects of ARS. By measuring the patient’s leukocyte count and the rate at which it was falling, the doctors could provide a corresponding estimate of the dose each had received.
