Nuclear and radiological emergencies: Building capacity in medical physics to support response

Low-dose brain radiation: lowering hyperphosphorylated-tau without increasing DNA damage or oncogenic activation

Brain radiation has been medically used to alter the metabolism of cancerous cells and induce their elimination. Rarely, though, brain radiation has been used to interfere with the pathomechanisms of non-cancerous brain disorders, especially neurodegenerative disorders. Data from low-dose radiation (LDR) on swine brains demonstrated reduced levels of phosphorylated-tau (CP13) and amyloid precursor protein (APP) in radiated (RAD) versus sham (SH) animals. Phosphorylated-tau and APP are involved in Alzheimer's disease (AD) pathogenesis. We determined if the expression levels of hyperphosphorylated-tau, 3R-tau, 4R-tau, synaptic, intraneuronal damage, and DNA damage/oncogenic activation markers were altered in RAD versus SH swine brains. Quantitative analyses demonstrated reduced levels of AT8 and 3R-tau in hippocampus (H) and striatum (Str), increased levels of synaptophysin and PSD-95 in frontal cortex (FCtx), and reduced levels of NF-L in cerebellum (CRB) of RAD versus SH swine. DNA damage and oncogene activation markers levels did not differ between RAD and SH animals, except for histone-H3 (increased in FCtx and CRB, decreased in Str), and p53 (reduced in FCtx, Str, H and CRB). These findings confirm the region-based effects of sLDR on proteins normally expressed in larger mammalian brains and support the potential applicability of LDR to beneficially interfere against neurodegenerative mechanisms.

Basic concepts of radiation emergency medicine

Nuclear and radiological accidents are not frequent but may lead to major consequences in the population. For the health systems, the need to handle a large number of victims will probably remain as an exception. However, a high number of affected victims can be expected in some terrorist scenarios. In addition, medical accidents in radiotherapy, fluoroscopy and diagnostic radiology have increased the number of patients with severe radiation injuries considerably, especially in developed countries. Given the increased use of ionising radiation for industrial and medical purposes and new technological applications emerging, the number of accidents may increase in the future. Consequently, the early identification and adequate management of these emergencies is a priority, as well as the need for medical preparedness, requiring knowledge about various emergency scenarios and planning appropriate responses to them before they occur. Unfortunately, medical professionals have a substantial knowledge gap in identifying and treating injured persons affected by ionising radiation. As managing radiation accidents is a very challenging process, exercises must be carried out to organise a well-trained multidisciplinary group of professionals to manage any radiation accident properly. Efforts on a continuously updated guidance system should be developed. In addition, new approaches to foster sustainable interdisciplinary and international cooperative networks on radiation injuries are necessary. Lessons learned from past nuclear and radiological emergencies have significantly contributed to strengthening scientific knowledge and increasing the available medical information on the effects of ionising radiation in the human body. In this context, radiation emergency medicine has emerged as a discipline that contributes to the diagnosis, treatment, medical follow-up and prognosis of persons affected by radiation injuries in a nuclear or a radiological emergency. In this paper, we review some relevant concepts related to the medical preparedness and multidisciplinary response required to attend to persons affected by these emergencies.

Reduction of pTau and APP levels in mammalian brain after low-dose radiation

Brain radiation can occur from treatment of brain tumors or accidental exposures. Brain radiation has been rarely considered, though, as a possible tool to alter protein levels involved in neurodegenerative disorders. We analyzed possible molecular and neuropathology changes of phosphorylated-Tau (pTau), all-Tau forms, β-tubulin, amyloid precursor protein (APP), glial fibrillary acidic protein (GFAP), ionized calcium binding adaptor molecule 1 (IBA-1), myelin basic protein (MBP), and GAP43 in Frontal Cortex (FC), Hippocampus (H) and Cerebellum (CRB) of swine brains following total-body low-dose radiation (1.79 Gy). Our data show that radiated-animals had lower levels of pTau in FC and H, APP in H and CRB, GAP43 in CRB, and higher level of GFAP in H versus sham-animals. These molecular changes were not accompanied by obvious neurohistological changes, except for astrogliosis in the H. These findings are novel, and might open new perspectives on brain radiation as a potential tool to interfere with the accumulation of specific proteins linked to the pathogenesis of various neurodegenerative disorders.

Medical physics workforce: A global perspective

PURPOSE

The International Organization for Medical Physics (IOMP) performed a detailed study following the first survey published in 2015 with the particular objectives: 1) gather data on global medical physicists (MPs) workforce, 2) identify differences between geographical regions and, 3) investigate whether there is a gender dimension in higher hierarchy positions.

METHODS

An online questionnaire was send to IOMP members and contact points in countries where no professional MPs society existed. Information requested: total number (N) of MPs (men and women), N of current elected executive board (EB) of societies and women proportion in the board, president gender and number of women presidents for the last 10 years. IOMP archives were also investigated for data on gender composition related to chairs of committees, officers and IOMP awardees.

RESULTS

Ninety three countries reported 29,179 MPs, from which 8702 were women (29.8%) and 20,477 men. The most dense MPs population was in Europe (34%), followed by North America (33%) and Asia/Oceania (24%). Societies EB women members constitute 21-40%, but rarely reach the presidential position. The IOMP archived data show that women MP representation decreases in higher hierarchy positions.

CONCLUSIONS

Global MPs production does not meet clinical needs especially in Latin America/Caribbean and Africa (6% of total MPs workforce and small number of MPs/million of population). Rough estimations showed that approximately 58,950 MPs will be required by 2035. Women representation is away from the United Nations and European Commissions goals. Women representation in higher hierarchy position is low.