Joint EURADOS-EANM initiative for an advanced computational framework for the assessment of external dose rates from nuclear medicine patients.

Background: In order to ensure adequate radiation protection of critical groups such as staff, caregivers and the general public coming into proximity of nuclear medicine (NM) patients, it is necessary to consider the impact of the radiation emitted by the patients during their stay at the hospital or after leaving the hospital. Current risk assessments are based on ambient dose rate measurements in a single position at a specified distance from the patient and carried out at several time points after administration of the radiopharmaceutical to estimate the whole-body retention. The limitations of such an approach are addressed in this study by developing and validating a more advanced computational dosimetry approach using Monte Carlo (MC) simulations in combination with flexible and realistic computational phantoms and time activity distribution curves from reference biokinetic models.

Optimizing the Safety and Efficacy of Bio-Radiopharmaceuticals for Cancer Therapy.

The precise delivery of cytotoxic radiation to cancer cells through the combination of a specific targeting vector with a radionuclide for targeted radionuclide therapy (TRT) has proven valuable for cancer care. TRT is increasingly being considered a relevant treatment method in fighting micro-metastases in the case of relapsed and disseminated disease. While antibodies were the first vectors applied in TRT, increasing research data has cited antibody fragments and peptides with superior properties and thus a growing interest in application.

Heterogeneity of absorbed dose distribution in kidney tissues and dose-response modelling of nephrotoxicity in radiopharmaceutical therapy with beta-particle emitters: A review.

Absorbed dose heterogeneity in kidney tissues is an important issue in radiopharmaceutical therapy. The effect of absorbed dose heterogeneity in nephrotoxicity is, however, not fully understood yet, which hampers the implementation of treatment optimization by obscuring the interpretation of clinical response data and the selection of optimal treatment options. Although some dosimetry methods have been developed for kidney dosimetry to the level of microscopic renal substructures, the clinical assessment of the microscopic distribution of radiopharmaceuticals in kidney tissues currently remains a challenge.

Extremity exposure of nuclear medicine workers: results from an EANM and EURADOS survey.

Background: Extremity exposure during the handling of unsealed radioactive sources is a matter of concern for nuclear medicine workers. Next to Tc and F, other radiopharmaceuticals have seen an increase in their use over the last decade. However, limited information on their impact on extremity dose is available.

A Realistic Multiregion Mouse Kidney Dosimetry Model to Support the Preclinical Evaluation of Potential Nephrotoxicity of Radiopharmaceutical Therapy.

Suborgan absorbed dose estimates in mouse kidneys are crucial to support preclinical nephrotoxicity analyses of α- and β-particle-emitting radioligands exhibiting a heterogeneous activity distribution in the kidneys. This is, however, limited by the scarcity of reference dose factors (S values) available in the literature for specific mouse kidney tissues. A computational multiregion model of a mouse kidney based on high-resolution MRI data from a healthy mouse kidney was developed.

Preclinical Evaluation of 225Ac-Labeled Single-Domain Antibody for the Treatment of HER2pos Cancer.

Human epidermal growth factor receptor type 2 (HER2) is overexpressed in various cancers; thus, HER2-targeting single-domain antibodies (sdAb) could offer a useful platform for radioimmunotherapy. In this study, we optimized the labeling of an anti-HER2-sdAb with the α-particle-emitter 225Ac through a DOTA-derivative. The formed radioconjugate was tested for binding affinity, specificity and internalization properties, whereas cytotoxicity was evaluated by clonogenic and DNA double-strand-breaks assays.

Assessment of mouse-specific pharmacokinetics in kidneys based on I activity measurements using micro-SPECT.

Background: In order to acquire accurate drug pharmacokinetic information, which is required for tissue dosimetry, micro-SPECT must be quantitative to allow for an accurate assessment of radioligand activity in the relevant tissue. This study investigates the feasibility of deriving accurate mouse-specific time-integrated drug pharmacokinetic data in mouse kidneys from activity measurements using micro-SPECT.

Methods: An animal experiment was carried out to evaluate the accuracy of I activity quantification in mouse kidneys (mean tissue volume of 0.

Review of extremity dosimetry in nuclear medicine.

The exposure of the fingers is one of the major radiation protection concerns in nuclear medicine (NM). The purpose of this paper is to provide an overview of the exposure, dosimetry and protection of the extremities in NM. A wide range of reported finger doses were found in the literature.

An international multi-center investigation on the accuracy of radionuclide calibrators in nuclear medicine theragnostics.

Background: Personalized molecular radiotherapy based on theragnostics requires accurate quantification of the amount of radiopharmaceutical activity administered to patients both in diagnostic and therapeutic applications. This international multi-center study aims to investigate the clinical measurement accuracy of radionuclide calibrators for 7 radionuclides used in theragnostics: Tc, In, I, I, I, Lu, and Y.

Methods: In total, 32 radionuclide calibrators from 8 hospitals located in the Netherlands, Belgium, and Germany were tested.

Therapeutic Efficacy of Bi-labeled sdAbs in a Preclinical Model of Ovarian Cancer.

Targeted alpha-particle therapy (TAT) might be a relevant therapeutic strategy to circumvent resistance to conventional therapies in the case of HER2-positive metastatic cancer. Single-domain antibody fragments (sdAb) are promising vehicles for TAT because of their excellent properties, high target affinity, and fast clearance kinetics. This study combines the cytotoxic α-particle emitter bismuth-213 (Bi) and HER2-targeting sdAbs.

OPTIMIZATION OF A RADIOPHOTOLUMINESCENT GLASS DOSEMETER FOR OCCUPATIONAL EYE LENS DOSIMETRY IN INTERVENTIONAL RADIOLOGY/CARDIOLOGY.

Hospital based workers that perform interventional radiology are at risk of reaching the eye lens dose limit of 20 mSv/y. These workers are exposed to the radiation scattered by the patient, which creates a complex field, with low radiation energy reaching the eyes of the medical staff from wide angles. Therefore, the dosemeter used in the assessment of the eye lens dose of interventional radiologists needs to respond accurately in such conditions.

Effect of protective devices on the radiation dose received by the brains of interventional cardiologists.

Aims: This study aimed to evaluate the effectiveness of ceiling suspended screens, lead glasses and lead caps in reducing radiation doses to the brains of interventional cardiologists.

Methods And Results: Interventional procedures where the thorax of the patient is irradiated with different beam projections were modelled. The dose reduction in the white matter and hippocampus of the Zubal head phantom was studied for two sizes of ceiling suspended screens, two types of lead glasses and lead caps of surgical and hood models, which cover different regions of the head.

Skin contamination of nuclear medicine technologists: incidence, routes, dosimetry and decontamination.

Objective: Nuclear medicine technologists are exposed daily to the risk of skin contamination with radiopharmaceuticals. This study deal with the different elements associated with skin contaminations.

Methods: To assess the incidence, routes and contamination activities, a long-term on-site survey was organized using a measurement system built in-house, together with a protocol based on fast detection, localization and quantification.