Eurados review of retrospective dosimetry techniques for internal exposures to ionising radiation and their applications

Abstract

This work presents an overview of the applications of retrospective dosimetry techniques in case of incorporation of radionuclides. The fact that internal exposures are characterized by a spatially inhomogeneous irradiation of the body, which is potentially prolonged over large periods and variable over time, is particularly problematic for biological and electron paramagnetic resonance (EPR) dosimetry methods when compared with external exposures. The paper gives initially specific information about internal dosimetry methods, the most common cytogenetic techniques used in biological dosimetry and EPR dosimetry applied to tooth enamel. Based on real-case scenarios, dose estimates obtained from bioassay data as well as with biological and/or EPR dosimetry are compared and critically discussed. In most of the scenarios presented, concomitant external exposures were responsible for the greater portion of the received dose. As no assay is available which can discriminate between radiation of different types and different LETs on the basis of the type of damage induced, it is not possible to infer from these studies specific conclusions valid for incorporated radionuclides alone. The biological dosimetry assays and EPR techniques proved to be most applicable in cases when the radionuclides are almost homogeneously distributed in the body. No compelling evidence was obtained in other cases of extremely inhomogeneous distribution. Retrospective dosimetry needs to be optimized and further developed in order to be able to deal with real exposure cases, where a mixture of both external and internal exposures will be encountered most of the times.

The role of dosimetry and biological effects in metastatic castration–resistant prostate cancer (mCRPC) patients treated with 223Ra: first in human study

“…Internal exposures are generally more complex to manage than external exposures. As highlighted by a recent review [ 30 ], the local absorbed dose rates (generally higher in the tumor and lower in the OARs) follow complex patterns which depend on the physical, chemical and metabolic properties of the radionuclide(s) and on patients’ anatomical characteristics. The irradiation of the body is spatially inhomogeneous, potentially prolonged over large periods and variable over time; thus, internal exposures become particularly problematic for biological dosimetry methods.…”

Eurados Strategic Research Agenda 2020: Vision for the Dosimetry of Ionising Radiation

“…New equipment and methods for in vivo and in vitro monitoring of radionuclides incorporated in the body are required ( 52 ) . These include the development of validated MC methods using age-scaled computational phantoms (voxel or mesh phantoms) for the calibration of body counters, assessment of internal doses, particularly for children and the improvement of emergency in vitro radiobioassay.…”

Contribution of Biological and EPR Dosimetry to the Medical Management Support of Acute Radiation Health Effects

“…These studies examined the intake of 239,240 Pu, 137 Cs and 98,90 Sr by the populations living around the Semipalatinsk test site [75][76][77] as well as the intake of 89,90 Sr and 137 Cs by the population living near the Techa River [78,79]. However, EPR was shown to be most applicable when radionuclides are distributed homogenously in the body [80].…”