Standard Practice for Blood Irradiation Dosimetry

Importancia y uso:

4.1 Blood and blood components are irradiated to predetermined absorbed doses to inactivate viable lymphocytes to help prevent transfusion-induced graft-versus-host disease (GVHD) in certain immunocompromised patients and those receiving related-donor products (1, 2).9

4.2 The assurance that blood and blood components have been properly irradiated is of crucial importance for patient health. This shall be demonstrated by means of accurate absorbed-dose measurements on the product, or in simulated product.

4.3 Blood and blood components are usually irradiated using gamma radiation from ¹³⁷Cs or ⁶⁰Co sources, or X-radiation from X-ray units.

4.4 Blood irradiation specifications include a lower limit of absorbed dose, and may include an upper limit or central target dose. For a given application, any of these values may be prescribed by regulations that have been established on the basis of available scientific data (see 2.5).

4.5 For each blood irradiator, an absorbed-dose rate at a reference position within the canister is measured as part of irradiator acceptance testing using a reference-standard dosimetry system. That reference-standard measurement is used to establish operating parameters so as to deliver specified dose to blood and blood components.

4.6 Absorbed-dose measurements are performed within the blood or blood-equivalent volume for determining the absorbed-dose distribution. Such measurements are often performed using simulated product (for example, polystyrene is considered blood equivalent for ¹³⁷Cs photon energies).

4.7 Dosimetry is part of a measurement management system that is applied to ensure that the radiation process meets predetermined specifications (see ASTM Practice 52628).

4.8 Blood and blood components are usually irradiated in chilled or frozen condition. Care should be taken, therefore, to ensure that the dosimeters and radiation-sensitive indicators can be used under such temperature conditions.

4.9 Proper documentation and record keeping are critical components of a radiation process. Documentation and record keeping requirements may be specified by regulatory authorities or may be given in the corporation’s quality policy.

4.10 Response of most dosimeters has significant energy dependence at photon energies of less than 100 keV, so proper care must be exercised when measuring absorbed dose in that energy range.

Subcomité:

E61.04

Volúmen:

12.02

Número ICS:

11.040.20 (Transfusion, Infusion), 17.240 (Radiation measurements)

Palabras clave:

absorbed dose; absorbed-dose mapping; blood; blood components; blood products; blood irradiation; bremsstrahlung; dosimeter; dosimetry system; gamma radiation; irradiator; ionizing radiation; measurement quality assurance plan; measurement uncertainty; radiation-sensitive indicators; reference-standard dosimeter; routine dosimeter; transfer-standard dosimeter; ICS 17.240; X-radiation;