2f:T51e,

The 2007 Recommendations of the Commission introduced the system of radiological protection based on the exposure situations, replacing the former practice-intervention–based system. For graded approaches, three types of exposure situations were specified: the planned exposure situations, the emergency exposure situations, and the existing exposure situations. In addition, three categories of exposure and the corresponding three types of exposed persons are identified, namely, occupational exposure of workers, public exposure of members of the public, and medical exposure of patients. The Commission explains that the new system clarifies and simplifies the system, leading to a unified approach. Experiences of application of the system to practice, however, have revealed several problems. For instance, the Commission's position on the application of the system to certain major occupational exposures, cosmic radiation exposure of aircrew, and radon exposure at workplaces specifically is equivocal. Accordingly, the current system is critically reviewed to propose possible improvements. An alternative approach, based on the autonomy of the exposed person and the degree of informed consent, is also proposed for consideration to make the logic of graded approaches easily understandable.

30:T542,

Although boron neutron capture therapy (BNCT) causes minimal damage to normal cells, accurately estimating the exposure dose based on radiation protection is crucial. This study was aimed at estimating the amount of radionuclides required for radioactivation and the internal exposure dose in BNCT by simulation calculations considering factors that were not taken into account in previous studies. This study was performed with reference to the BNCT clinical studies conducted at a reactor-based BNCT facility. Five irradiated parts of the head and neck regions were selected for estimation. The contribution of each radionuclide to the equivalent dose in each organ indicated that the effects of ²⁴Na, ³²P, and ¹²⁸I were significant. ²⁴Na is uniformly distributed throughout the body. The contribution of ³²P to the bone surface and red marrow was remarkable. Because ¹²⁸I is produced only in the thyroid, its effect was small, depending on the irradiated part. The calculated effective dose was one order of magnitude lower than that of the external exposure. Therefore, internal exposure is not negligible for exposure dose estimation in BNCT, and it is necessary to consider the irradiation component in treatment planning to avoid exposure to certain critical organs.

31:T463,

In the current system of radiological protection, radiation effects are classified as either tissue reactions (also known as deterministic effects) or stochastic effects. The objectives of the system are to manage and control exposures to ionising radiation so that harmful tissue reactions are prevented, and the risks of stochastic effects are reduced to the extent reasonably achievable. Thus, the classification of health effects is a very important pillar of the system of radiological protection. In recent years, there has been debate regarding the adequacy of the current scheme for classifying health effects. Recent publications, including those from ICRP, have highlighted the need for a review of the ICRP scheme for health effects classification. This article outlines the basis for the establishment of ICRP Task Group (TG) 123 and the outlined tasks, the key sources of uncertainties for consideration, the agreed approach and timeline to tackle the above tasks, as well as the links with and dependencies on the other ongoing developments to the system being considered by the other ICRP task groups.

32:T4cc,

When calculating dose rates around an Am–Be source, one typically focuses on the neutron emission. In high activity Am–Be sources, there is a need to consider two additional contributors to the dose: low-energy photon emission from the ²⁴¹Am decay (59.5 keV and an