Blood irradiator dosimetry with BANG polymer gels

Abstract

Transfusion-associated graft-versus-host disease is believed to be a preventable complication of blood transfusion in susceptible high-risk patients. Irradiation of allogeneic blood components is considered to be a safe and effective method inhibiting the proliferative capacity of lymphocytes. Physical factors that influence dose delivery include source and sample geometry, homogeneity of the dose distribution within the irradiation volume, and factors that influence dose absorption within the sample. Polymer gel dosimetry was used to evaluate the three-dimensional dose distribution for blood bags, platelet (PLT) bags, and syringes in typical geometries. The qualitative dose distribution within a cylindrical phantom determined with the polymer gel was in good agreement with the distribution in water determined with a DOSE-MAP film dosimetry system. Dose uniformity in blood bags and syringes was acceptable. Low signal strength and volume averaging hamper determination of the dose in PLT bags. Geometrical considerations in routine blood product irradiation may be evaluated with the use of polymer gel dosimetry. The procedures, however, are highly technical and are susceptible to low signal-to-noise and volume averaging considerations under certain geometrical configurations. Under clinical conditions, a reasonably uniform dose can be delivered to blood and blood components in a freestanding irradiator.