Radiation Protection Research Articles

Colorectal cancer screening with virtual colonography

Since 2003, adecline in the age-standardized incidence rates of colorectal cancer (CRC) has been observed in Germany. Nonetheless, one in eight cancer cases still affects the colon or rectum. The prognosis has improved, with the relative 5‑year survival rate for CRC being approximately 65%. This positive trend is probably aresult of preventive measures introduced over the last 20years. This could be further improved, however, as CRC can not only be detected early but in almost all cases also prevented through the identification of benign precursors. Less than half of all eligible individuals participate in screening via colonoscopy. This implies that further, possibly even imaging, screening test methods should be explored and offered. Studies have reported that virtual colonography techniques have acomparable accuracy to endoscopy of about 90% for polyp sizes larger than 5 mm. The data for computed tomography (CT) is more extensive than for magnetic resonance imaging (MRI). Significant challenges are posed however by the fact that in Germany CT colonography (CTC) is not considered aviable screening option due to radiation protection concerns, and MRI screening is not an established screening method. Radiologists should be familiar with classification using the CT Colonography Reporting and Data System (C-RADS), which uses criteria such as CT density, morphology, size, and location for classification. C‑RADS classification follows the categories: C0 (inadequate study), C1 (normal), C2a (indeterminate), C2b (benign), C3 (suspicious), and C4 (malignant), as well as extracolonic categories E1/2 (no clinically significant findings), E3 (likely insignificant findings), and E4 (likely significant findings).

Synthesis of the European ALARA network 20th workshop ‘ALARA for interventional radiology and nuclear medicine’

The European as low as reasonably achievable(ALARA) network regularly organises workshops on topical issues in radiation protection (RP). The topic of the 20th workshop was: ‘ALARA for interventional radiology (IR) and nuclear medicine (NM)’. The objective was to examine the challenges faced when applying the optimisation principle (ALARA) in IR and NM and to consider how ALARA could be better implemented for patient and staff exposures. This memorandum provides a synthesis of the workshop sessions, and recommendations coming from the working groups discussion. Parallels are drawn with the recommendations arising from the 13th EAN workshop on ‘ALARA and the medical sector (2011)’ to consider how the optimisation challenges in IR and NM have evolved over the past decade. Current levels of exposure are presented along with operational practice and the challenges and opportunities for improvement, both in monitoring and practice. Whilst RP challenges remain, the application of ALARA appears more established in IR compared with experiences reported in 2011. The application of ALARA to emerging technologies in the NM setting is in need of further development to ensure that RP is considered at all stages in the development process of new radiopharmaceuticals. Besides the obvious technical and operational aspects, the importance of education and training, human factors and broadly the RP ‘culture’ were deemed fundamental to the success of the application of ALARA and where further emphasis is needed. All concerned parties, medical physics experts (MPEs), radiation protection experts, clinical staff, manufacturers and regulators have a role to play in the application of ALARA and this is discussed in the memorandum. Many of the recommendations from the 13th EAN workshop remain applicable today and overlap with the recommendations arising from the 20th workshop. This should prompt attention given that the use of IR and the development of novel radiopharmaceuticals for NM is only anticipated to increase with time.

In-depth exploration of the radiation exposure to staff performing endoscopic retrograde cholangiopancreatography procedures (ERCP) through RANDO phantom and TLDs.

This study provides a comprehensive evaluation of the occupational radiation exposure faced by healthcare professionals during Endoscopic Retrograde Cholangiopancreatography (ERCP) procedures. Utilizing an anthropomorphic RANDO phantom equipped with Thermoluminescent Dosimeters (TLDs), we replicated ERCP scenarios to measure radiation doses received by medical staff. The study meticulously assessed radiation exposure in various corresponding body regions typically occupied by medical staff during ERCP, with a focus on eyes, thyroid, hands, and reproductive corresponding organ regions. The findings revealed significant variations in radiation doses across different body parts, highlighting areas of higher exposure and underscoring the need for improved protective measures and procedural adjustments. The effective radiation doses were calculated using standard protocols, considering the varying levels of protection offered by lead aprons and thyroid shields. The results demonstrate the substantial radiation exposure experienced by healthcare staff, particularly in regions not adequately shielded. This study emphasizes the necessity for enhanced radiation safety protocols in clinical settings, advocating for advanced protective equipment, training in radiation safety, and the exploration of alternative imaging modalities. The findings have crucial implications for both patient and staff safety, ensuring the continued efficacy and safety of ERCP and similar interventional procedures. This research contributes significantly to the field of occupational health and safety in interventional radiology, providing vital data for the development of safer medical practices.

Medical staff dose estimation during pediatric cardiac interventional procedures.

The purpose of this study is to evaluate the occupational doses (eye lens, extremities and whole body) in paediatric cardiac interventional and diagnostic catheterization procedures performed in a paediatric reference hospital located in Recife, Pernambuco. For eye lens dosimetry, the results show that the left eye receives a higher dose than the right eye, and there is a small difference between the doses received during diagnostic (D) and therapeutic (T) procedures. The extrapolated annual values for the most exposed eye are close to the annual limit. For doses to the hands, it was observed that in a significant number of procedures (37 out of 45 therapeutic procedures, or 82%) at least one hand of the physician was exposed to the primary beam. During diagnostic procedures, the physician's hand was in the radiation field in 11 of the 17 catheterization procedures (65%). This resulted in a 10-fold increase in dose to the hands. The results underscore the need for optimization of radiation safety and continued efforts to engage staff in a radiation safety culture.&#xD.

Relationship between assistant's lens exposure and dose information during computed tomography examinations.

According to International Commission of Radiological Protection (ICRP), the equivalent dose limit for the eye lens for occupational exposure is recommended to be 20 mSv/y, averaged over 5 years, with no single year above 50 mSv. Some studies reported the measurement of assistant's lens exposure in diagnostic computed tomography (CT) examinations, but further investigation is still required in the association between the lens dose for assistants and various dose parameters. Therefore, we measured the assistant's lens exposure using small optically stimulated luminescence dosimeters. The type of occupation, type of assistance, total scan time, total mAs, total scan length, and dose-length product (DLP) were recorded and analyzed in association with air kerma at the lens position. The assistance was classified into four types: "assisted ventilation," "head holding," "body holding," and "raising patient's arm." The air kerma of lens position was not significantly different for each assistance type (p < 0.05, Kruskal-Wallis test). Further, the lens doses for assistants correlated with DLP, but with various strengths of correlation with the assistance type and were influenced by the distance from the CT gantry. In conclusion, lens dose during assistance and DLP demonstrated the strongest correlation. "Raising patient's arm" and "head holding" exhibited stronger correlations, which required less table movement during the CT scan than "assisted ventilation" and "body holding."

Dosimetric Considerations for 177Lu-DOTATATE Therapy in a Patient With Chronic Renal Failure Under Hemodialysis

Abstract This case report explores the use of 177Lu-DOTATATE in a hemodialysis patient. For the first time, this study assesses the average dose received by the bone marrow, the primary organ at risk, using an original double estimation method through independently acquired imaging and biological samples counting data. Despite elevated doses, the absorbed doses to the bone marrow (0.662–0.740 Gy) were within safe limits. Radiation protection measurements for staff were also compliant. This work supports that effective early dialysis and systematic personalized dosimetry are crucial for hemodialysis patients undergoing 177Lu-PRRT due to their variability (residual excretion, treatment history, etc).

Whole-body SAR measurements of millimeter-wave base station in reverberation chambers

Abstract This paper presents a method for measuring whole-body specific absorption rate (WBSAR) of millimeter-wave base stations (BSs) in a reverberation chamber (RC). The absorbed power in the phantom from the equipment under test (EUT) and hence WBSAR is determined as the difference between the total radiated power with and without the phantom. A chamber transfer function is determined and used to include only the absorption in the phantom due to direct illumination from the EUT, i.e., excluding absorption due to the RC multipath reflections. The measurement method was evaluated at 28 GHz using a horn antenna and a commercial massive multi-input–multi-output BS. The experimental results are in good agreement with simulations. The proposed method allows for measurements of WBSAR within 3 minutes, which is much shorter than traditional approaches. The method is suitable for compliance assessments of BS products with the International Commission on Non-Ionizing Radiation Protection 2020 electromagnetic field exposure guidelines, which extend the applicability of WBSAR as basic restrictions up to 300 GHz.

Dynamic model of changes in the trophic structure of an ecosystem affected by chronic radiation exposure

The conceptual dynamic ecosystem model was developed to evaluate the self-organization of trophic structure in ecosystems during the course of biogenic succession. This model was applied to analyze the possible changes in the ecosystem under impact of the anthropogenic physical stressor – chronic exposure to ionizing irradiation. The model predicts that amount of the limiting biogenic nutrient in the environment can modify the ecological effects of ionizing radiation. Negative effects of the chronic exposure are less significant in ecosystems with high food supply. The model does not show presence of any ecological effect of radiation at the exposure rates less than the derived consideration reference levels, obtained by International Commission on Radiological Protection for individual nature organisms. If the dose rates are higher than those levels, radiation exposure can affect ecological interactions between species. The model shows that environmental hormesis can exist in the ecosystems, impacted by the chronic radiation exposure. The reason of this effect is change of the ecological coefficients (for example, decrease of the predation rate), which in the certain range of parameters leads to the increase of biomasses of all species at the same amount of the limiting biogenic nutrient in ecosystem. Trigger regimes exist in the model ecosystem with mixed-feeding consumers. Within the trigger area, the realization of a particular trophic structure depends on initial species biomasses. A hysteresis phenomenon exists in such ecosystems, which means that the successive changes in the trophic structures realized following the increase of the influencing factor are not reproduced in the same order if the influencing factor was gradually decreased back to its previous values. The model predicts for this case, that the radioactively contaminated ecosystem does not necessarily return to its initial trophic structure, despite the dose rate decreases to the initial levels.

Thermal expansion, lattice vibration, and isotope effect on hydrogen diffusion in BCC Fe, Cr, and W from first-principles calculations.

Fe, Cr, and W are important elements in the alloys of in-reactor materials and operate in high-temperature environments with thermal expansion. Their tritium-impeding abilities are crucial to the radiation safety of various nuclear reactors. In this study, first-principles density functional theory is combined with quasi-harmonic approximation to evaluate factors that can affect the interstitial formation energy and diffusion coefficient of hydrogen isotopes in body-centered cubic (BCC) Fe, Cr, and W, including thermal expansion, metal host lattice vibrations, phonon density-of-states (pDOS) coupling diffusing atoms, and isotope effects. Calculation results indicate that the interstitial formation energy decreases as lattice expansion increases, whereas the jump barriers remain almost constant. Thermal expansion, host lattice vibration, and pDOS coupling minimally affect the diffusion coefficients of hydrogen isotopes in Fe, Cr, and W. The diffusion coefficient ratios between hydrogen isotopes are higher than the inverse ratio of the square root of the isotope mass at low temperatures. However, they decrease to the inverse ratio of the square root of the isotope mass at temperatures exceeding 800K. This study comprehensively investigates factors that affect the diffusion coefficients of hydrogen isotopes in BCC Fe, Cr, and W, thus providing a firm theoretical foundation for predicting the diffusion coefficients of tritium at different temperatures using protium/deuterium diffusion coefficients.

Radiation Exposure and Safety Considerations in Interventional Radiology: Comparison of a Twin Robotic X-ray System to a Conventional Angiography System

Background/Objectives: To evaluate radiation exposure in standard interventional radiology procedures using a twin robotic X-ray system compared to a state-of-the-art conventional angiography system. Methods: Standard interventional radiology procedures (port implantation, SIRT, and pelvic angiography) were simulated using an anthropomorphic Alderson RANDO phantom (Alderson Research Laboratories Inc. Stamford, CT, USA) on an above-the-table twin robotic X-ray scanner (Multitom Rax, Siemens Healthineers, Forchheim, Germany) and a conventional below-the-table angiography system (Artis Zeego, Siemens Healthineers, Forchheim, Germany). The phantom’s radiation exposure (representing the potential patient on the procedure table) was measured with thermoluminescent dosimeters. Height-dependent dose curves were generated for examiners and radiation technologists in representative positions using a RaySafe X2 system (RaySafe, Billdal, Sweden). Results: For all scenarios, the device-specific dose distribution differs depending on the imaging chain, with specific advantages and disadvantages. Radiation exposure for the patient is significantly increased when using the Multitom Rax for pelvic angiography compared to the Artis Zeego, which is evident in the dose progression through the phantom’s body as well as in the organ-related radiation exposure. In line with these findings, there is an increased radiation exposure for the performing proceduralist, especially at eye level, which can be significantly minimized by using protective equipment (p &lt; 0.001). Conclusions: In this study, the state-of-the-art conventional below-the-table angiography system is associated with lower radiation dose exposures for both the patient and the interventional radiology physician compared to an above-the-table twin robotic X-ray system for pelvic angiographies. However, in other clinical scenarios (port implantation or SIRT), both devices are suitable options with acceptable radiation exposure.

Effects of cell parameters on accurate calculation of activation dose after DT explosion for local hot spots in laser-driven ICF facilities

Instruments placed in the target chamber will be highly activated after DT explosion in laser-driven ICF experiments, especially for the part near the chamber center. Operations near those local hot spots are the main concern for radiation protection due to its high contribution to the occupation exposure dose, therefore it becomes very important to calculate the dose during the operating process accurately. Cell-based rigorous two-step (R2S) method has been introduced to deal with the activated objects with highly heterogeneous distribution, and the effects of cell size, materials as well as radiation source have also been specified to improve the accuracy of simulations. Results for a typical model sample show that with a given distribution of radiation source, cell size in the simulations placed a significant influence on the accuracy of the radiation field. A cell size of 50 cm for a 100 cm cone-shaped sample will lead to the inaccuracy of the radiation field as large as an order in magnitude within the location 50 cm from the surface of the sample. While for the same sample model, cell size should be limited to smaller than 2 cm to ensure an accuracy lower than ±10 %. In addition, the effects of the material and source energy on the calculation accuracy for the radiation field could be neglected if the cell size is limited to smaller than 5 cm. Furthermore, the influence of cell size increased as the distance from the sample surface decreased, which indicates that appropriate cell size must be chosen to ensure the accuracy of dose estimation, especially for surface contact operations. Besides, a significant difference between the effective dose and skin-equivalent dose has been observed for the typical mode used in the calculations.

Radiation Safety Assessment in Prostate Cancer Treatment: A Predictive Approach for I-125 Brachytherapy

This study uses Monte Carlo simulation and experimental measurements to develop a predictive model for estimating the external dose rate associated with permanent radioactive source implantation in prostate cancer patients. The objective is to estimate the accuracy of the patient’s external dose rate measurement. First, I-125 radioactive sources were implanted into Mylar window water phantoms to simulate the permanent implantation of these sources in patients. Water phantom experimental measurement was combined with Monte Carlo simulation to develop predictive equations, whose performance was verified against external clinical data. The model’s accuracy in predicting the external dose rate in patients with permanently implanted I-125 radioactive sources was high (R2 = 0.999). A comparative analysis of the experimental measurements and the Monte Carlo simulations revealed that the maximum discrepancy between the measured and calculated values for the water phantom was less than 5.00%. The model is practical for radiation safety assessments, enabling the evaluation of radiation exposure risks to individuals around patients with permanently implanted I-125 radioactive sources.

A survey of the radiation safety practices of veterinary practitioners during portable equine radiography in Ireland.

Veterinary practitioners and other personnel involved in the examination are exposed to ionizing radiation while performing portable radiographs on horses. An online survey was distributed to all Veterinary Council of Ireland-registered practices where the self-reported practice profile is at least 20% equine work. The survey contained questions relating to radiation safety training, protocols, personal dosimetry and lead protection usage, repeat exposures, sedation, and personnel roles during the examination. The aim of the survey was to document the current radiation safety practices of equine veterinary practitioners during portable radiography. The results showed that although adherence to guidance set out by the Environmental Protection Agency (EPA) is reasonably good, compliance rates can be improved. Personal dosemeter usage and repeat rate reduction could particularly benefit from further improvement. This is of the utmost importance in ensuring that occupational radiation exposure to veterinary practitioners is kept to an absolute minimum during their daily practice.

An experimental and theoretical study to evaluate Al2O3–PbO–B2O3–SiO2–BaO radiation shielding properties

This study's objective is to evaluate an Al2O3–PbO–B2O3–SiO2–BaO glass system's radiation shielding characteristics. The composition of the glasses is 15Al2O3–25PbO–(60-x)B2O3–10SiO2–xBaO, with x in the 5–20 mol% range. Experimental results were used to determine the samples' linear attenuation coefficients (LAC), which were then confirmed by Phy-X program. Utilizing narrow beam transmission geometry, the experimental LAC values were determined. According to the results there was high agreement when comparing the theoretical and experimental values. The LAC values were used to calculate the prepared glasses' mass attenuation coefficients (MAC) and other relevant properties. The mean free path (MFP) values of the sample with 5 mol% BaO were 0.079, 2.549, 3.944 and 4.273 cm at 0.0595, 0.662, 1.173, and 1.332 MeV, thus demonstrating that raising the glass system's BaO enhances the prepared glasses' shielding capacity. According to radiation protection efficiency (RPE), the glasses' capacity to shield the photon is enhanced when their BaO content rises.

Radiation Safety for Women in Cardiology: Myths and Important Messages

Accurate fertility-based radiation safety data, education and knowledge is important for all staff exposed to occupational radiation. Women are under-represented in all medical fields with increased exposure to occupational radiation, to achieve better equity in our medical workforces evidence-based radiation safety knowledge is essential to overcoming perceived career barriers. This review of radiation safety policy and data focuses on providing health professions working in cardiology with accurate contemporary information about potential radiation exposure with respect to fetal risk for pregnant health professionals. The data summarized within this review shows when women continue to work in cardiac catheterization laboratories through pregnancy their expected occupational radiation exposure with appropriate shielding, will not meaningfully change pregnancy outcomes, nor will it significantly increase risk to the fetus. The review also summarizes international workplace policy for radiation exposure and monitoring and provides recommendations for ongoing safe practice.

Managing radiation safety and protection in gastroenterology in Japan: insights from the REX-GI study.

Fluoroscopy-guided gastrointestinal procedures, including gastrointestinal stenting, balloon-assisted endoscopy (BAE), endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound (EUS), are essential for diagnosis and treatment in gastroenterology. Such procedures involve radiation exposure that necessitates strict safety measures to protect patients, doctors, and medical staff. The April 2020 update to Japan's Ionizing Radiation Injury Prevention Regulations for occupational exposure reduced the lens exposure dose limit to approximately one-seventh of its previous level. This change highlights the need for improved safety protocols. Without adaptation, the sustainability of fluoroscopy-based endoscopic techniques could be at risk due to the potential to exceed these new limits. This review examines the current state of medical radiation exposure in the field of gastroenterology in Japan and discusses the findings of the REX-GI study.

An approach to assess the consequence of a hypothetical radionuclide release in Singapore - a densely populated urban setting

This study is to demonstrate an approach to investigate the consequence of a hypothetical radionuclide release scenario in Singapore, a typical urban setting with high population density. To this end, we made use of MACCS 4.1, a Gaussian-based atmospheric dispersion model to compute the peak dose and the population health effects. We developed the meteorological and site files from data provided by local government agencies. Our investigation showed that the chosen scenario poses very little to negligible risk to the health of local population as the peak dose received across the country is below the radiation safety level recommended by ICRP.

Investigation of red clay and waste glass composite bricks for ionizing radiation shielding

Ionizing radiation is valuable for healthcare, industry, and agriculture. However, excessive exposure to ionizing radiation is detrimental to humans and the environment. Radiation protection aims at protecting people and the environment from the harmful effects of ionizing radiation. This work aimed to study the effectiveness of composites of red clay and waste glass for ionizing radiation shielding. Five samples of different mix ratios of red clay to waste glass were fabricated into different dimensions using hand molding, dried, and burnt. The samples were characterized for ionizing radiation shielding. Monte-Carlo simulation was done using the GEANT4 toolkit and web-based NIST-XCOM photon attenuation database. The findings show that the measured half value layer (HVL) for the composite bricks showed a linear decrease from (6.13± 0.10) cm for the CNT sample that had 0 % waste glass to (4.62± 0.12) cm for the RCG11 sample that had 50 % waste glass. The GEANT4 simulated HVL values for CNT and RCG11 samples were (6.05±0.01) cm and (4.79±0.01) cm respectively. The NIST-XCOM values were (6.09±0.09) cm and (4.81± 0.01) cm for CNT and RCG11 respectively. The measured and simulated results were in good agreement. The findings of this study indicate an improvement in the shielding properties of red clay with the addition of waste glass and will promote radiation safety by providing an environmentally friendly alternative shielding material.•Proper shielding is key in promoting radiation safety and protection. There is a need for alternative shielding materials that can be used for walling during the construction of structures that house radioactive materials.•Red clay and waste glass composite bricks can provide alternative ionizing radiation shielding material.•This study will promote environmentally friendly practices in radiation safety and protection.

NCRP commentary no. 33—recommendations for stratification of equipment use and radiation safety training for fluoroscopy

National Council on Radiation Protection and Measurements Commentary No. 33 ‘Recommendations for Stratification of Equipment Use and Radiation Safety Training for Fluoroscopy’ defines an evidence-based, radiation risk classification for fluoroscopically guided procedures (FGPs), provides radiation-related recommendations for the types of fluoroscopes suitable for each class of procedure, and indicates the extent and content of training that ought to be provided to different categories of facility staff who might enter a room where fluoroscopy is or may be performed. For FGP, radiation risk is defined by the type and likelihood of radiation hazards that could be incurred by a patient undergoing a FGP. The Commentary also defines six training groups of facility staff based on their role in the fluoroscopy room. The training groups are based on a combination of job descriptions and the procedures in which these individuals might be involved. The Commentary recommends the extent and content of training that should be provided to each of these training groups. It also provides recommendations on training formats, training frequency, and methods for demonstrating that the learner has acquired the necessary knowledge.

High-radiation-exposure tasks in Korean pressurized heavy-water reactors.

This study analysed the occupational dose in Korean pressurized heavy-water reactors (PHWRs) and identified tasks involving high radiation exposure. The average individual dose was sufficiently low to be below the annual effective dose limit for radiation workers and is even lower than the dose limit for the general public. However, some workers received relatively higher doses than others. Furthermore, most PHWR workers are exposed to radiation during planned maintenance periods. In this study, the radiation dose was normalized (radiation dose per unit time) to determine the high-radiation-exposure tasks in Korean PHWRs. Consequently, end-fitting lapping, delayed neutron tube work and fuel channel fixed-end change tasks were identified as high-radiation-exposure tasks in Korean PHWRs. If appropriate radiation protection measures are prioritized for the identified high-dose exposure tasks, optimization of radiological protection will be effectively achieved by reducing the dose that is relatively higher than the average.