scholarly journals BRAIN AND EYE AS POTENTIAL TARGETS FOR IONIZING RADIATION IMPACT: PART II – RADIATION CEREBRO-OPHTALMIC EFFECTS IN CHILDREN, PERSONS EXPOSED IN UTERO, ASTRONAUTS AND INTERVENTIONAL RADIOLOGISTS

Author(s):  
K. Loganovsky ◽  
◽  
P. Fedirko ◽  
D. Marazziti ◽  
K. Kuts ◽  
...  

Background. Ionizing radiation (IR) can affect the brain and the visual organ even at low doses, while provoking cognitive, emotional, behavioral, and visual disorders. We proposed to consider the brain and the visual organ as potential targets for the influence of IR with the definition of cerebro-ophthalmic relationships as the «eye-brain axis». Objective. The present work is a narrative review of current experimental, epidemiological and clinical data on radiation cerebro-ophthalmic effects in children, individuals exposed in utero, astronauts and interventional radiologists. Materials and methods. The review was performed according to PRISMA guidelines by searching the abstract and scientometric databases PubMed/MEDLINE, Scopus, Web of Science, Embase, PsycINFO, Google Scholar, published from 1998 to 2021, as well as the results of manual search of peer-reviewed publications. Results. Epidemiological data on the effects of low doses of IR on neurodevelopment are quite contradictory, while data on clinical, neuropsychological and neurophysiological on cognitive and cerebral disorders, especially in the left, dominant hemisphere of the brain, are nore consistent. Cataracts (congenital – after in utero irradiation) and retinal angiopathy are more common in prenatally-exposed people and children. Astronauts, who carry out longterm space missions outside the protection of the Earth’s magnetosphere, will be exposed to galactic cosmic radiation (heavy ions, protons), which leads to cerebro-ophthalmic disorders, primarily cognitive and behavioral disorders and cataracts. Interventional radiologists are a special risk group for cerebro-ophthalmic pathology – cognitive deficits, mainly due to dysfunction of the dominant and more radiosensitive left hemisphere of the brain, and cataracts, as well as early atherosclerosis and accelerated aging. Conclusions. Results of current studies indicate the high radiosensitivity of the brain and eye in different contingents of irradiated persons. Further research is needed to clarify the nature of cerebro-ophthalmic disorders in different exposure scenarios, to determine the molecular biological mechanisms of these disorders, reliable dosimetric support and taking into account the influence of non-radiation risk factors. Key words: ionizing radiation, brain, eye, cerebro-ophthalmic effects, radiation emergencies, prenatal irradiation, space flights, interventional radiology.

1984 ◽  
Vol 23 (02) ◽  
pp. 87-91 ◽  
Author(s):  
K. Flemming

SummaryIn the beginning of medical radiology, only the benefit of ionizing radiation was obvious, and radiation was handled and applied generously. After late effects had become known, the radiation exposure was reduced to doses following which no such effects were found. Thus, it was assumed that one could obtain an optimal medical benefit without inducing any hazard. Later, due to experimental findings, hypotheses arose (linear dose-effect response, no time factor) which led to the opinion that even low and lowest radiation doses were relevant for the induction of late effects. A radiation fear grew, which was unintentionally strengthened by radiation protection decrees: even for low doses a radiation risk could be calculated. Therefore, it was believed that there could still exist a radiation hazard, and the radiation benefit remained in question. If, however, all presently known facts are considered, one must conclude that large radiation doses are hazardous and low doses are inefficient, whereas lowest doses have a biopositive effect. Ionizing radiation, therefore, may cause both, hazard as well as benefit. Which of the two effects prevails is determined by the level of dose.


Dose-Response ◽  
2007 ◽  
Vol 5 (4) ◽  
pp. dose-response.0 ◽  
Author(s):  
R. E. J. Mitchel

The Linear No Threshold (LNT) hypothesis states that ionizing radiation risk is directly proportional to dose, without a threshold. This hypothesis, along with a number of additional derived or auxiliary concepts such as radiation and tissue type weighting factors, and dose rate reduction factors, are used to calculate radiation risk estimates for humans, and are therefore fundamental for radiation protection practices. This system is based mainly on epidemiological data of cancer risk in human populations exposed to relatively high doses (above 100 mSv), with the results linearly extrapolated back to the low doses typical of current exposures. The system therefore uses dose as a surrogate for risk. There is now a large body of information indicating that, at low doses, the LNT hypothesis, along with most of the derived and auxiliary concepts, is incorrect. The use of dose as a predictor of risk needs to be re-examined and the use of dose limits, as a means of limiting risk needs to be re-evaluated. This re-evaluation could lead to large changes in radiation protection practices.


2020 ◽  
Vol 3 ◽  
pp. 36-39
Author(s):  
Samson O. Paulinus ◽  
Benjamin E. Udoh ◽  
Bassey E. Archibong ◽  
Akpama E. Egong ◽  
Akwa E. Erim ◽  
...  

Objective: Physicians who often request for computed tomography (CT) scan examinations are expected to have sound knowledge of radiation exposure (risks) to patients in line with the basic radiation protection principles according to the International Commission on Radiological Protection (ICRP), the Protection of Persons Undergoing Medical Exposure or Treatment (POPUMET), and the Ionizing Radiation (Medical Exposure) Regulations (IR(ME)R). The aim is to assess the level of requesting physicians’ knowledge of ionizing radiation from CT scan examinations in two Nigerian tertiary hospitals. Materials and Methods: An 18-item-based questionnaire was distributed to 141 practicing medical doctors, excluding radiologists with work experience from 0 to >16 years in two major teaching hospitals in Nigeria with a return rate of 69%, using a voluntary sampling technique. Results: The results showed that 25% of the respondents identified CT thorax, abdomen, and pelvis examination as having the highest radiation risk, while 22% said that it was a conventional chest X-ray. Furthermore, 14% concluded that CT head had the highest risk while 9% gave their answer to be conventional abdominal X-ray. In addition, 17% inferred that magnetic resonance imaging had the highest radiation risk while 11% had no idea. Furthermore, 25.5% of the respondents have had training on ionizing radiation from CT scan examinations while 74.5% had no training. Majority (90%) of the respondents were not aware of the ICRP guidelines for requesting investigations with very little (<3%) or no knowledge (0%) on the POPUMET and the IR(ME)R respectively. Conclusion: There is low level of knowledge of ionizing radiation from CT scan examinations among requesting physicians in the study locations.


2021 ◽  
Vol 231 ◽  
pp. 189-197
Author(s):  
Jalmar Teeuw ◽  
Anil P.S. Ori ◽  
Rachel M. Brouwer ◽  
Sonja M.C. de Zwarte ◽  
Hugo G. Schnack ◽  
...  

iScience ◽  
2021 ◽  
pp. 102313
Author(s):  
Yusuke Matsuno ◽  
Mai Hyodo ◽  
Mafuka Suzuki ◽  
Yosuke Tanaka ◽  
Yasunori Horikoshi ◽  
...  

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1058
Author(s):  
Sebastiano Mercadante ◽  
Marco Maltoni ◽  
Domenico Russo ◽  
Claudio Adile ◽  
Patrizia Ferrera ◽  
...  

The aim of this study was to assess the prevalence and characteristics of breakthrough cancer pain (BTcP) in patients receiving low doses of opioids for background pain. A consecutive sample of advanced cancer patients receiving less than 60 mg/day of oral morphine equivalent (OME) was selected. Epidemiological data, background pain intensity, and current analgesic therapy were recorded. The presence of BTcP was diagnosed according to a standard algorithm. The number of BTcP episodes, intensity of BTcP, its predictability and triggers, onset duration, interference with daily activities, BTcP medications, satisfaction with BTcP medication, and time to meaningful pain relief were collected. A total of 126 patients were screened. The mean intensity of background pain was 2.71 (1.57), and the mean OME was 28.5 mg/day (SD15.8). BTP episodes were recorded in 88 patients (69.8%). The mean number/day of BTP episodes was 4.1 (SD 7.1, range 1–30). In a significant percentage of patients, BTcP was both predictable and unpredictable (23%). The BTcP onset was less than 20 min in the majority of patients. The mean duration of untreated episodes was 47.5 (SD 47.6) minutes. The mean time to meaningful pain relief after taking a BTcP medication was >20 min in 44.5% of patients. The efficacy of BTcP medication was not considered good in more than 63% of patients. Gender (females) (OR = 4.16) and lower Karnofsky (OR = 0.92) were independently associated with BTcP. A higher number of BTcP episodes/day was associated with gender (females) (p = 0.036), short duration of BTcP (p = 0.005), poorer efficacy of BTcP medication (none or mild) (p = 0.001), and late meaningful pain relief (p = 0.024). The poor efficacy of BTcP medication was independently associated with a higher number of episodes/day (OR = 0.22). In patients who were receiving low doses of opioids, BTcP prevalence was 69.8%. Many patients did not achieve a sufficient level of satisfaction with BTcP medications, particularly with oral morphine. Data also suggest that better optimization of background analgesia, though apparently acceptable, may limit the number of BTcP episodes.


Hypertension ◽  
2014 ◽  
Vol 63 (5) ◽  
pp. 894-903 ◽  
Author(s):  
Christophe Tzourio ◽  
Stéphane Laurent ◽  
Stéphanie Debette
Keyword(s):  

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