Applications of NIST Alanine/EPR Dosimetry to the Irradiation of Blood and Blood Products

At present, gamma irradiation of blood products is the only procedure known to prevent transfusion-associated graft-versus-host disease (TA-GVHD).

The most common irradiation sources used are ⁶⁰Co and ¹³⁷Cs. Most blood centers rely on a nominal dose of 25 Gy with no less than 15 Gy delivered to any area of the bag for these radiation beams to inactivate lymphocytes in cellular products for transfusion. International Specialty Products (ISP) is a commercial manufacturer of a variety of film products that are used for the verification of irradiation of blood or validation of a blood irradiator's performance.

In 2004, NIST was contacted by ISP about the possibility of using alanine dosimetry to provide traceability of the ISP dose-mapping service for blood irradiators to national standards.  Throughout the several years of experience with dosimetry measurements at this relatively low range for the alanine system, adaptations and refinements have led to a protocol that will be incorporated into the existing alanine transfer dosimetry service. On a near weekly basis, NIST continues to provide measurement services of alanine dosimeters that have been co-located with ISP films in blood-irradiator canisters.