Prevention of Transfusion-Associated Graft-versus-Host Disease by Irradiation: Technical Aspect of a New Ferrous Sulphate Dosimetric System

Abstract

Irradiation of whole blood and blood components before transfusion is currently the only accepted method to prevent Transfusion-Associated Graft-Versus-Host-Disease (TA-GVHD). However, choosing the appropriate technique to determine the dosimetric parameters associated with blood irradiation remains an issue. We propose a dosimetric system based on the standard Fricke Xylenol Gel (FXG) dosimeter and an appropriate phantom. The modified dosimeter was previously calibrated using a 60Co teletherapy unit and its validation was accomplished with a 137Cs blood irradiator. An ionization chamber, standard FXG, radiochromic film and thermoluminescent dosimeters (TLDs) were used as reference dosimeters to determine the dose response and dose rate of the 60Co unit. The dose distributions in a blood irradiator were determined with the modified FXG, the radiochromic film, and measurements by TLD dosimeters. A linear response for absorbed doses up to 54 Gy was obtained with our system. Additionally, the dose rate uncertainties carried out with gel dosimetry were lower than 5% and differences lower than 4% were noted when the absorbed dose responses were compared with ionization chamber, film and TLDs.

Technical Note: Fricke dosimetry for blood irradiators

“…Furthermore, only the canister central plane was considered in the analysis of the mean doses. Although they did not find a significant difference between the dosimeters, the results for relative final uncertainty are not described 6 . The Fricke solution dosimetry can be considered an alternative to TLD or FXG, due its low associated uncertainties, and lower costs, even when working with a primary level dosimeter.…”

“…Studies already claim that the dose delivered to the entire blood bag must have at least 25 Gy. This recommendation takes into account changes in the recovery of transfused cells derived from irradiated bags, the erthrocyte, granulocyte and platelet functions, and changes in biochemistry 6,25 . The design of the developed phantom allowed the verification that the dose inside the canister is not uniformly distributed, because of this, some of the irradiated blood bags will not receive the recommended dose of 25 Gy.…”

“…Thus, the associated control of blood irradiation is necessary to guarantee the quality of the transfused product. Current articles show that 25 Gy, no less, is the ideal minimum dose for inactivating more than 90% of lymphocytes, and <25 Gy may have been the cause of death of some patients 5‐7 …”

Characterization of Sarcoptes scabiei cofilin gene and assessment of recombinant cofilin protein as an antigen in indirect-ELISA for diagnosis

“…As a measure of potential diagnostic performance, sensitivity and specificity were calculated: Sensitivity = ELISA positive samples/ S. scabiei infected samples × 100 %; Specificity = ELISA negatives samples/ S. scabiei non-infected samples × 100 % [ 27 , 28 ]. The cut-off value between negative and positive results was calculated as the average measurement of the mange negative animals plus three times the standard deviation [ 29 – 31 ].…”

Young donor white blood cell immunotherapy induces extensive tumor necrosis in advanced-stage solid tumors

“…In addition, leukocytes should be non-irradiated. While irradiation helps to minimize the risk of GVHD [13] , Stehle Jr. et al and other studies showed that irradiation of donor leukocytes had a profound suppressive effect on the CKA and survival of irradiated compared to non-irradiated granulocytes [ 11 , 14 ].…”