Proton and ion beams are radiotherapy modalities of increasing importance and interest. Because of the different biological dose response of these radiations as compared with high-energy photon beams, the current approach of treatment prescription is based on the product of the absorbed dose to water and a biological weighting factor, but this is found to be insufficient for providing a generic method to quantify the biological outcome of radiation. It is therefore suggested to define new dosimetric quantities that allow a transparent separation of the physical processes from the biological ones. Given the complexity of the initiation and occurrence of biological processes on various time and length scales, and given that neither microdosimetry nor nanodosimetry on their own can fully describe the biological effects as a function of the distribution of energy deposition or ionization, a multiscale approach is needed to lay the foundation for the aforementioned new physical quantities relating track structure to relative biological effectiveness in proton and ion beam therapy. This article reviews the state-of-the-art microdosimetry, nanodosimetry, track structure simulations, quantification of reactive species, reference radiobiological data, cross-section data and multiscale models of biological response in the context of realizing the new quantities. It also introduces the European metrology project, Biologically Weighted Quantities in Radiotherapy, which aims to investigate the feasibility of establishing a multiscale model as the basis of the new quantities. A tentative generic expression of how the weighting of physical quantities at different length scales could be carried out is presented.

The IAEA is currently coordinating a multi-year project to update the TRS-398 Code of Practice for the dosimetry of external beam radiotherapy based on standards of absorbed dose to water. One major aspect of the project is the determination of new beam quality correction factors, k _Q , for megavoltage photon beams consistent with developments in radiotherapy dosimetry and technology since the publication of TRS-398 in 2000. Specifically, all values must be based on, or consistent with, the key data of ICRU Report 90. Data sets obtained from Monte Carlo (MC) calculations by advanced users and measurements at primary standards laboratories have been compiled for 23 cylindrical ionization chamber types, consisting of 725 MC-calculated and 179 experimental data points. These have been used to derive consensus k _Q values as a function of the beam quality index TPR _20,10 with a combined standard uncertainty of 0.6%. Mean values of MC-derived chamber-specific f c h factors for cylindrical and plane-parallel chamber types in ⁶⁰ Co beams have also been obtained with an estimated uncertainty of 0.4%.

This paper investigates over five decades of work practices in interventional cardiology, with an emphasis on radiation protection. The analysis is based on data from more than 400 cardiologists from various European countries recruited for a EURALOC study and collected in the period from 2014 to 2016. Information on the types of procedures performed and their annual mean number, fluoroscopy time, access site choice, x-ray units and radiation protection means used was collected using an occupational questionnaire. Based on the specific European data, changes in each parameter have been analysed over decades, while country-specific data analysis has allowed us to determine the differences in local practices. In particular, based on the collected data, the typical workload of a European cardiologist working in a haemodynamic room and an electrophysiology room was specified for various types of procedures. The results showed that when working in a haemodynamic room, a transparent ceiling-suspended lead shield or lead glasses are necessary in order to remain below the recommended eye lens dose limit of 20 mSv. Moreover, the analysis revealed that new, more complex cardiac procedures such as chronic total occlusion, valvuloplasty and pulmonary vein isolation for atrial fibrillation ablation might contribute substantially to annual doses, although they are relatively rarely performed. The results revealed that considerable progress has been made in the use of radiation protection tools. While their use in electrophysiology procedures is not generic, the situation in haemodynamic procedures is rather encouraging, as ceiling-suspended shields are used in 90% of cases, while the combination of ceiling shield and lead glasses is noted in more than 40% of the procedures. However, we find that still 7% of haemodynamic procedures are performed without any radiation protection tools.

Exposure to low-doses of ionising radiation can induce biological effects in healthcare professionals, such as DNA damage, genotoxic effects, lens opacities, and risk of cancer. This systematic review aims to assess the current status and identify the health impacts of occupational exposure to ionising radiation. The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Articles were included only if they specifically addressed the adverse biological effects of ionising radiation on healthcare professionals, particularly in medical applications. Studies published between January 2019 and December 2023 were considered, with sources obtained from the Scopus, PubMed, and Web of Science databases. A total of 345 articles were identified through an extensive literature search, and after the complete text screening, 32 articles were deemed suitable for inclusion in the review. Eleven studies reported significantly higher micronuclei (MN) frequencies in workers exposed to ionising radiation compared to unexposed. The MN studies reviewed found a significant correlation between dose or exposure time and MN frequencies. All studies revealed significantly higher chromosomal aberrations (CA) values when exposed to ionising radiation. The occurrence of lens opacities among interventional physicians varied significantly, with rates ranging from 16% to 47%. This review emphasizes the high occurrence of cataracts, increased cancer risk, and the relevant frequency of MN and CA in workers chronically exposed to low doses.