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Cardiovascular nuclear medicine (NM) imaging examinations expose patients to extremely high absorbed doses of ionizing radiation, which necessitates extensive efforts to reduce the doses without compromising the quality of images. This study aims to assess patients' radiation doses to patients and public exposure in Cardiac rest and stress single photon emission computed tomography (SPECT) scans. The patients' exposure was calculated for 21 patients using the administered activity (AA, MBq). (GE SPECT) was the device used for all patients. AA (MBq) mean and range were 370 for Rest and 1110 for Stress. The average range of the dose rate was 1.59 (0.67–2.34) mR/h for rest and 7.29 (4.2–9.98) mR/h for stress when computed at 30 cm from the patient's chest level after injection. At 100 cm from the patient, the mean dose rate values were 0.37 (0.16–0.73) mR/h for rest and 1.39 (1.01–2.0) mR/h for stress. The overall effective dose is 12.1 mSv per rest and stress SPECT procedure. The mean effective dose for cardiac rest is comparable with previously published studies while the effective dose from cardiac stress is higher than previously published studies. The variation in the effective dose depends on several factors, including the department's clinical indication imaging protocols and radiation safety measures. • The patient's effective dose and dose were quantified during cardiac rest and stress SPECT procedures. • The mean effective dose for cardiac rest is comparable with previously published studies. • The effective dose from cardiac stress is higher than previously published studies. • The current AA activity for rest and stress is lower than the DRL and the previous studies. [ABSTRACT FROM AUTHOR]

Synthetic dyes were considered harmful due to their toxic, carcinogenic, and nonbiodegradable chemicals. Anionic (congo red (CR) and methyl orange (MO)) and cationic (methylene blue (MB) and Janus green B (JGB)) dyes are used in this study due to their ability to restrict oxygen and sunlight dispersion. The discharge of dyes can degrade aquatic systems. This study has investigated the potential of dyes' adsorption behaviour in silica nanocapsules (SiNCs) adsorbents. Silica nanocapsules (SiNCs) were synthesized using oil-in-water (o/w) emulsion by employing different solvents (ethanol (SiNC E), ethyl ether (SiNC EE), and toluene (SiNC T) to understand the effect of solvents on SINCs' structure and effective dye adsorption. Which found that toluene and ethyl ether were effective solvents to produce silica nanocapsules. SiNC T and SiNC EE were both hollow cores, while the SiNC E structure was spherical. SiNC T adsorbent had high selectivity removal of CR > MO and JGB > MB, in which the adsorption capacity was 0.102 mmol/g at pH 2, 0.029 mmol/g at pH 2, 0.0999 mmol/g at pH 10, and 0.0944 mmol/g at pH 12 for 24 h for CR, MO, JGB, and MB, respectively. The kinetic study shows that the adsorption of dyes follows pseudo-second-order. The experimental data followed the Langmuir isotherm model and gave maximum adsorption capacities of 0.0979 and 0.4147 mmol/g for CR and JGB, respectively. SiNC T was recycled and reused for six consecutive cycles. Developed adsorbents are low-cost, highly efficient, and viable materials to be used in wastewater treatment. [Display omitted] • Silica nanocapsules was successfully synthesized via oil-in-water emulsion. • SiNC T exhibited outstanding dye adsorption capacity. • SiNC T showed remarkable adsorption capacities of 95 mmol/g for JGB, 10.9 mmol/g for CR. • SiNC T 's adsorption behaviour fit Langmuir and pseudo-second kinetics. [ABSTRACT FROM AUTHOR]

Abstract: An idea that improves the wettability over the surfaces of a cylindrical dehumidifier channel was proposed and experimentally proved. Fibrous sheets were attached to the inner surfaces of the channel. The capillary effect of fibers sustains the complete wetting of the heat and mass transfer surfaces. The air to be dehumidified and cooled flows upward in the annulus space between the two layers of fibrous sheets, which are saturated with the downward flowing desiccant solution. The permeability of the fibrous sheet was determined experimentally. It was 2.43×10−10 m2. The measured solution flow rate due to the capillary suction of the sheets was Γin,min =1.12kg/h m. The liquid desiccant tested was H2O/CaCl2 with salt concentration ratios ranging from 35 to 40%. The measured distribution of the solution flow rate along the circumference of the sheets at the outlet showed 5% deviation from the average flow rate. This is a good indication for the good wettability of walls inside the dehumidifier. Feeding the solution by this mechanism has many advantages over spray feeding. Beside sustaining complete surface wetting, it also prevents channel blockage with solution, which is a main factor in increasing the air pressure drop. About 95% of the air pressure drop is saved in this study by avoiding these problems. A simple theoretical model for the heat and mass transfer processes inside the dehumidifier was developed and experimentally validated. In general, there is good agreement between the predicted and measured data. The developed model was utilized to study the effect of the different parameters on the dehumidifier performance. For a 1m height dehumidifier with an inlet specific humidity and air temperature of 0.0234kgv/kga, and 35°C, respectively, the predicted outlet air specific humidity was 0.0102kgv/kgk and the corresponding outlet air temperature was 27.4°C. The inlet solution temperature and salt concentration were 25°C and 40%, respectively. [Copyright &y& Elsevier]

In the present study, patient exposures Evaluations herein concern patient exposures (positron and gamma-rays) that result from fluoro-D-g1ucose PET and CT were investigated and radio-carcinogenic risks estimated. The six-month study, conducted at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, included a total of 636 patients (lymphoma = 187, nasopharyngeal carcinoma = 82, thyroid = 30 and others = 337). Patient effective dose estimations were made from administered radioactivity (AA) and CT exposures (General Electric (GE) PET/CT VCT), the mean and range of AA (in MBq) and effective dose (in mSv) were respectively: lymphoma 433.9 ± 70.6 (297.5–735.9) and 8.2 ± 1.3 (5.7–13.9); nasopharyngeal carcinoma 417.7 ± 55.9 (325.6–547.6) and 7.9 ± 1.1 (6.2–10.4); thyroid 450.1 ± 71.4 (344.1–566.1) and 8.6 ± 1.4 (6.5–10.8). In the same units, the mean and range of AA and effective dose for other procedures were 421.6 ± 58.3 (283.4–606.8) and 8.0 ± 1.1 (5.4–11.5), respectively. The mean and range of the tube current-time product (mAs) for the CT procedures were 30 (8.2–42.4). A constant tube voltage of 120 kVp was used for all patient procedures. On average, CT contributed 73% to patient effective doses, suggesting that optimisation of CT acquisition parameters are vital in seeking effective dose reduction. Patient effective doses were found to be a little above that of previous studies. • Radiation dose was measured for patients undergoing PET/CT procedures. • Patient doses from PET/CT procedures are higher compared to those reported in previous studies. • CT contributed 73% to patient effective doses while (18F-FDG, PET) contributed 27%. • Patients were exposed to avoidable radiation dose from CT in PET/CT imaging. [ABSTRACT FROM AUTHOR]

The capacities, abilities and potential of Ni–C 36 , Ni–Al 18 P 18 , Co–C 54 , Co–Ge 54 , Co-CNT(7, 0), Co-GeNT(7, 0), Ni-CNT(10, 0) and Ni-AlPNT(10, 0) to use as catalysts of OER and ORR are examined by theoretical models. The adsorption energy, free Gibbs adsorption energy, overpotential and Gibbs free energy values of ORR and OER on used catalysts are compared with other metal catalysts. The Ni and Co atoms which are doped on nanotubes and nanocages are catalytic positions to adsorb ORR and OER species the and to process the reaction steps of OER and ORR. The Co-GeNT(7, 0) and Ni-AlPNT(10, 0) have lower overpotential than Ni–C 36 , Ni–Al 18 P 18 , Co–C 54 and Co–Ge 54. Finally, the Co-GeNT(7, 0) and Ni-AlPNT(10, 0) are suggested as catalysts with acceptable stability, high capacity to adsorb the species, lower over-potential and high performances by theoretical models. [Display omitted] • Capacity of metal doped nano-catalysts for OER and ORR are investigated. • Metal doped nano-catalysts have acceptable potential to adsorb the ORR and OER species. • Reaction of *OH separation is potential-determining steps of ORR. • Nanotubes has lower overpotential than nanocages for ORR and OER. • Co-GeNT(7, 0) and Ni-AlPNT(10, 0) are proposed to catalyze the ORR and OER. [ABSTRACT FROM AUTHOR]

About 70% of all collective doses from medical tests come from computed tomography (CT), the primary public radiation exposure source. Patients received higher doses during contrast-enhanced CT procedures (Angiography) than routine CT procedures. The current research aims to quantify the patients' radiation doses, estimate the cancer risk probability, and establish institutional diagnostic reference level (IDRL) during lower extremity angiography. One hundred eleven patients (61.3% male and 38.7% female) underwent contrast-enhanced CT procedures. A 160-Slice CT scanner was used for image acquisition for all patient populations. IDRL values were quantified based on the 3rd quartile value of the CT dose descriptors. All procedures were carried out at Al-Moaallim Medical City, Khartoum, Sudan. A computer software (CT-Expo, ImPACT) was used to extrapolate the effective dosage per extremity CTA examination was estimated. The mean patient age (years) was 56.1 ± 18 (18–82). The patient's radiation doses was quantified using volume CTDI and dose length product (DLP) to 7.3 ± 2 (2.9–16.8) (mGy) and 3712 ± 126 (279–8374) (mGy.cm), respectively. The average effective doses were 22 mSv (range: 1.7–50) per lower CT angiography for the lower extremity. The proposed IDRL for the VCTA procedure was 3562 mGy cm and 17 mGy for DLP and CTDIvol, respectively. The proposed IDRL is higher than the previously published studies; therefore, patient dose optimization is recommended. • Radiation doses were determined for patients undergoing VCTA procedure. • A 160-Slice CT scanner with iterative reconstruction techniques was used for examining the patients. • The average effective doses were 22 mSv (range: 1.7–50) per VCTA. • The proposed LDRL for the VCTA procedure was 3562 mGy cm and 17 mGy for DLP and CTDIvol, respectively. [ABSTRACT FROM AUTHOR]

With the rapid increase in computed tomography (CT) examinations among pediatric patients, the concern about the effects of radiation exposure in this population has increased. Therefore, it is necessary to measure and regulate radiation exposure, which can be done using diagnostic reference levels (DRLs). This study aimed to calculate typical values for common pediatric studies at the radiology department of King Abdulaziz University Hospital Jeddah, Saudi Arabia. For a single institute, these are calculated as the median of computed tomography dose index (CTDIvol, mGy) or dose length product (DLP, mGy.cm) values. Pediatric patient data from January 2015 to December 2020 were collected, including CT examinations, dose descriptors, imaging protocols, and scanning parameters. A total of 8717 radiological studies were included in the sample. They were categorized into three age groups; more than half of the 5102 (58.5%) belonged to Group 1 (0–5 years), 1790 (20.5%) were in Group 2 (6–10 years), and 1826 (20.9%) were in Group 3 (11–15 years). Brain CT angiogram, non-enhanced brain CT, and Internal Auditory Canal (IAC) CT had the highest mean CTDI Vol and DLP, while virtual bronchoscopy contrast-enhanced chest and neck CT angiography had the lowest mean CTDI Vol. The values of DRLs in the current study were approximately lower than and comparable with those reported in other studies. • This study quantified pediatric doses during common CT procedures. • A total of 8717 radiological studies were included in the sample. • Local DRLs were established for common CT procedures. • The values of DRLs in the current study were lower than other studies. [ABSTRACT FROM AUTHOR]

The objective of present study is estimation of the radioactivity held within the urinary bladder and kidneys 3 h post radiopharmaceutical (99mTc-MDP) administration, comparison being made via use of MIRDose. Using the conjugate-view method and built-in camera software Mediso XP Interview, urinary bladder and kidney radionuclide activities were calculated using patient clinical data acquired at the aforesaid 3 h post 99mTc-MDP injection juncture. The study was of a cohort of 40 patients attending for staging and cancer follow-up at the Nuclear Medicine Department, Royal Care International Hospital (RCIH), Sudan, Ethical and Research Committee approval for the study having been obtained. The radioisotope biokinetics were simulated using the Medical Internal Radiation Dose (MIRD) biokinetics model, specifically in regard to radionuclide activity in the kidneys and bladder. The results were compared with the data achieved via clinical study, showing the experimentally estimated radionuclide activity in the kidney to be greater by some 50% compared to that of simulation while the bladder radionuclide activity was found to be just 2% of the simulation result. The study also found that 0.9% of the administered radioactivity remained in the urinary bladder and kidneys 3 h post administration of the radionuclide, suggestive of low radiation dose to the urinary bladder and kidneys post 99mTc-MDP bone scans. • 99mTc-MDP radionuclide biokinetics were simulated using MIRD biokinetics model. • Radionuclide activities for Urinary bladder and kidney were calculated. • The experimentally estimated radionuclide activity in the kidney to be greater by some 50%. • 0.9% of the administered radioactivity remained in the urinary bladder and kidneys 3 h. • Low radiation dose to the urinary bladder and kidneys post 99mTc-MDP bone scans. [ABSTRACT FROM AUTHOR]

Lutetium-177 (DOTATATE) (177Lu; T 1/2 6.7 days), a labelled β− and Auger-electron emitter, is widely used in treatment of neuroendocrine tumours. During performance of the procedure, staff and other patients can potentially receive significant doses in interception of the gamma emissions [113 keV (6.4%) and 208 keV (11%)] that are associated with the particle decays. While radiation protection and safety assessment are required in seeking to ensure practices comply with international guidelines, only limited published studies are available. The objectives of present study are to evaluate patient and occupational exposures, measuring ambient doses and estimating the radiation risk. The results, obtained from studies carried out in Riyadh over an 11 month period, at King Faisal Specialist Hospital and Research Center, concerned a total of 33 177Lu therapy patients. Patient exposures were estimated using a calibrated Victoreen 451P survey meter (Fluke Biomedical), for separations of 30 cm, 100 cm and 300 cm, also behind a bed shield that was used during hospitalization of the therapy patients. Occupational and ambient doses were also measured through use of calibrated thermoluminescent dosimeters and an automatic TLD reader (Harshaw 6600). The mean and range of administered activity (in MBq)) was 7115.2 ± 917.2 (4329–7955). The ambient dose at corridors outside of therapy isolation rooms was 1.2 mSv over the 11 month period, that at the nursing station was below the limit of detection and annual occupational doses were below the annual dose limit of 20 mSv. Special concern needs to be paid to comforters (carers) and family members during the early stage of radioisotope administration. • Occupational and ambient doses were monitored for nuclear medicine personnel over eleven months. • The dose was quantified using thermluminecent dosimeters. • Occupational doses were below the annual dose limits for whole body and extremities. • Patient isolation is necessary in order to ensure that family members and members of the public receive optimally low doses. [ABSTRACT FROM AUTHOR]

During the preparation of radioisotopes, during their administration and during patient imaging nuclear medicine personnel are routinely exposed to ionising radiation. With radiation risks increasing with dose, safety assessment is required in seeking to ensure practice complies with international guidelines and dose limits. A particular aim herein is to measure staff exposures during certain molecular imaging procedures including through use of positron emission tomography with computed tomography (PET/CT) and single photon emission computed tomography (SPECT) procedures. Over a one-year period occupational doses were monitored for 30 nuclear medicine personnel at King Faisal Specialist Hospital and Research Center (KFSH&RC) in Riyadh. Dose equivalent values were measured in terms of Hp (10) (deep dose) and Hp (0.07) (skin dose), extremity doses also being measured via ring dosimeters. The measurements were made using calibrated thermoluminescent dosimeters, type LiF:Mg, Ti (TLD-100). In mSv, the respective mean annual dose and range for H p (10), H p (0.07) and extremities were 3.05 ± 2.1 (0.23–0.91), 3.15 ± 2.2 (0.1–9.1) and 28.25 (0.1–298.0). In all cases, extremity dose values were well below the annual dose limit (500 mSv). Nevertheless, with personnel doses varying significantly, careful assessment of working conditions is recommended in efforts to ensure occupational exposures remain below annual dose limits. • Occupational doses were monitored for 30 nuclear medicine personnel over one year using thermoluminescent dosimeters. • The dose was quantified in terms of Hp (10) and Hp (0.07) and extremity doses. • Occupational doses were below the annual dose limits for whole body and extremities. • Careful assessment of working conditions are recommended in seeking to reduce gender differences in occupational exposures. [ABSTRACT FROM AUTHOR]

This article presents the physical, mechanical, optical, and radiation shielding properties of several articles discussing BaO-based glass systems prepared by the melt-quench technique. Specifically, the article discussed is an article that reports experimentally the effectiveness of BaO-based glass systems as shielding gamma-ray radiation at an energy of 0.662 MeV published since 2019. In addition, we also compare the theoretical effectiveness of several glass systems by recalculating using Phy- X/PSD based on the respective compositions reported by previous studies at several energies, namely: 0.284, 0.347, 0.662, 0.826, 1.173, 1.333, and 2.506 MeV. Based on the analysis, the Bi 2 O 3 –BaO–B 2 O 3 glass system is the best in terms of absorbing radiation. But it still needs to be developed to get the best physical, mechanical, and optical properties. With this article, scholars can more easily determine the composition of a BaO-based glass system to be applied as a more effective and high-quality radiation shield. • Evolution of gamma-ray radiation at an energy of 0.662 MeV published since 2019. • The theoretical effectiveness were calculated using Phy- X/PSD. at various energies. • The Bi2O3–BaO–B2O3 glass system is the best in terms of absorbing radiation. • Scholars easily determine composition BaO-based for effective radiation shield. • Physical, mechanical, and optical properties important in for BaO-based glass. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive bibliometric analysis to better understand the evolution of concrete composite as a radiation shielding research from when it was first published in 1949 to October 26, 2022. This study was conducted based on the Scopus database, and the publications analyzed a total of 541 documents. The data in this paper is visualized using the VOSviewer and Tableau to perform bibliometric analysis and scientific mapping. The analysis results show that published documents have continued to increase in recent years and are dominated by articles. Some countries show productivity and influence in their country/region with the broadest range of partners. This study presents the most contributed journals and the most frequently cited documents. In addition, keyword analysis was carried out to find the hotspots on this research topic. This paper helps scholars to understand the evolution of concrete composite as a radiation shielding research from a bibliometric perspective and inspires them to develop new concrete composite with high stability absorption properties from waste or natural material to replace concrete Lead (Pb)-based. • Evolution concrete composite as shielding research from 1949 to October 26, 2022. • Data perform using bibliometric analysis and scientific mapping. • To helps scholars, understand evolution of concrete composite as a radiation shield. • Bibliometric perspective help to develop new high absorption of concrete composite. • High stability from waste or natural material to replace concrete Lead (Pb)-based. [ABSTRACT FROM AUTHOR]

Occupational radiation exposure can occur due to various human activities, including the use of radiation in medicine. Occupationally exposed personnel surpassing 7.4 millions, and respresent the biggest single group of employees who are exposed to artificial radiation sources at work. This study compares the occupational radiation dose levels for 145 workers in four different hospitals located in the Aseer region in Saudi Arabia. The occupational exposure was quantified using thermoluminescence dosimeters (TLD-100). The levels of annual occupational exposures in targeted hospitals were calculated and compared with the levels of the international atomic energy agency (IAEA) Safety Standards. An average yearly cumulative dose for the two consecutive years. The average, highest and lowest resulted occupational doses under examination in this work is 1.42, 3.9 mSv and 0.72 for workers in various diagnostic radiology procedures. The resulted annual effective dose were within the IAEA approved yearly dose limit for occupational exposure of workers over 18, which is 20 mSv. Staff should be monitored on a regular basis, according to current practice, because their annual exposure may surpass 15% of the annual effective doses. • Annual occupational dose (Hp(10) were evaluated at four diagnostic radiology department. • Staff doses represent approximately 15% of the annual effective dose. • Students and trainees should be monitored on a regular basis, according to current practice. • Occupational exposure is comparable with the most previously published studies. [ABSTRACT FROM AUTHOR]

CT scanning deliver much higher radiation doses than planar radiological procedures, which puts patients to high risks. This study measures and evaluates patient doses during chest and abdomen computed tomography procedures. Particular attention is given to measuring the dose to the equivalent breast (mSv) and to estimate the associated risks of breast cancer to young female patients (15–35 years). Data was obtained from standard examinations from three hospitals. The measured values of CT dose indexes, CTDI (mGy) as well as exposure-related parameters were used for assessment. Breast and effective doses were extrapolated using a software. The results showed remarkable variations of the mean organ equivalent doses for similar CT examinations in the studied hospitals. This could be attributed to the variation in CT scanning imaging technique, and clinical indications. The average effective dose to the chest was 7.9 mSv (2.3–47.0 mSv) and for the abdomen the mean dose was 6.6 mSv, ranging from (3.3–27 mSv). The breast received equivalent doses from chest and abdomen procedures as follows: 10.2 (1.6–33 mSv) and 10.1(2.3–19 mS) Sv respectively. Each procedure yielded high risks of breast cancer for young females. Implementation of accurate referral criteria is recommended to avoid unnecessary breast radiation exposure. • Breast radiation doses for young females were evaluated during CT chest and abdomen procedures. • CT chest and abdomen procedures yielded high risks of breast cancer for young females. • Breast doses varied from 1.6 to 33 mSv during chest CT procedure. • Proper justification and optimization are recommended to save young females from potential radiogenic risks. [ABSTRACT FROM AUTHOR]

A significant source of ionizing radiation for medical use is computed tomography (CT). According to estimates, more than 84 million CT scans are carried out yearly in the US. Because the neck area contains several organs and tissues that are very sensitive to ionizing radiation, such as the thyroid gland, CT for the neck region is commonly done for a variety of clinical causes. This study's goal is to assess the patient doses to radiosensitive organs and effective doses received during the CT neck surgery in the pastAt Riyadh Care Hospital, a multislice CT (MSCT) system (Siemens Somatom Sensation, 64 slices/detector) was used to perform improved CT treatments on a total of 54 patients. Patient ages were 41.5–15.5 years old on average, with a wide variation (21–73). Using computer software based on Monte Carlo simulation, organ and effective dosages were assessed. The International Commission of Radiological Protection (ICRP) risk variables were used to calculate the patient's radiogenic risk for a particular organ. The patients' dose length product (DLP, mGy.cm) for CT neck examination were 993.3 ± 539.5 (267.3–2441.7). The mean and range of volume CT dose per slice (CTDIvol (mGy)) were 1.5 ± 3.9 (3.91–22.55). The overall effective dose (mSv) per procedure is ranged from 1.3 to 11.7 with a mean value 2.8 mSv. Patients' CT neck procedures have been repeated the procedure up to 7 times during the treatment course. The risk of malignancy is 1x10-6 CT procedure. The study showed that patients received wide discrepancies in patients' doses up to 9 times. Optimization of image acquisition protocol and scan length is necessary to reduce the unnecessary risk. • The effective and organ equivalent doses during neck CT procedure were studied. • Lens of the eye, salivary gland and thyroid gland received a high radiation dose. • The overall effective dose (mSv) per procedure is ranged from 1.3 to 11.7 • Patients' CT neck procedures have been repeated the procedure up to 7 times during the treatment course. [ABSTRACT FROM AUTHOR]

Artificial radiation is the primary radiogenic risk source to the general population. Medical field has been growing in Sudan. This study aims to estimate effective doses for adult patients from nuclear medicine examinations. The study involved 685 patients from five different hospitals in Sudan. In total, 300, 196, and 189 patients underwent renal, thyroid, and bone scans. All procedures were carried out using the Tc-99m radionuclide. Effective dose has been estimated using computer software depending on conductive activity. The results show that dose information for patients from thyroid, renal, and bone scan, for thyroid scan the patients' age was 42.82 ± 16.46 years, the patient's weight 68.58 ± 12.82 kg, the activity 4.75 ± 0.543 mCi and the effective dose for thyroid was 2.28 ± 0.26 mSv. For renal scan, the patients' age 45.19 ± 16.36 years, the weight 65.96 ± 13.78 kg, the activity 5.21 ± 1.166 mCi, and the effective dose 0.94 ± 0.211 mSv. For a bone scan, the patients' age was 57.59 ± 14.92 years, the patient's weight was 69.48 ± 13.71 kg, the activity 19.96 ± 2.11 mCi, and the effective dose for bone was 4.208 ± 0.443 mSv. The study revealed that the administered activity is independent of patient weight. Patients received unjustified exposure due to the high amount of administered activity. Implementation of national guidelines is necessary to improve the practice and patient safety. • Effective dose has been estimated for thyroid, renal and bone scan procedures. • Patients received the least effective dose during renal scan procedures. • The study revealed that the administered activity is independent of patient weight, according to the current protocol. • Proper optimization are recommended to save young from potential radiogenic risks. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) are often used for adult and pediatric patients. This is basically due to its powerful diagnostic capabilities in providing the tiniest details of pathologies in the body. Nevertheless, this detailed and accurate imaging occurs at the expense of the high doses received by the patients, although in general, the benefits outweighs the risks precisely of malignancy. Pediatrics are radiosensitive more than adults due to their longer life expectancy and their rapidly dividing cells. This study aims at measuring and evaluating pediatric patient doses in four hospitals equipped with 16, 20 and 128 CT detectors. Forty-eight pediatric patients who underwent brain (72.7%) and abdomen (36.3%) Computed Tomography are included in this study. Data includes CTDI vol (mGy) and DLP (mGy.cm). CTDOSE computer software which is based on Monte Carlo simulations was used to calculate the effective and organ equivalent doses (mSv). The CTDIvol (mGy) per procedure range was 11.0–95.0 mGy for brain CT and 3.0–30.0 mGy for abdomen CT. DLP on the other hand ranged between 129.0 and 2510.0 mGy cm for brain CT and 84.0–1604.0 for abdomen CT. The high doses were attributed to the fact that the protocols used for pediatric patients were the adult protocols, not bearing in mind the high radio-sensitivity of the pediatrics. Establishing a protocol for pediatric CT is hence of great importance to prevent them from receiving unnecessary high doses which may eventually cause cancer. • The radiation doses during specific pediatric CT examinations in four hospitals were evaluated. • Patient dose per CT procedure ranged from 84.0 to 2510.0 mGy cm. • Adults protocols used for pediatric patients resulted in unnecessary exposure. • Standardizing imaging protocols during pediatric CT imaging is recommended. [ABSTRACT FROM AUTHOR]

Staff occupational radiation exposure is limited to 20 mSv annually to preclude tissue reaction and lower risk of cancer effect. Staff occupational exposure arises during the preparation, injection, and scanning of the patients. Recent studies reported that nuclear medicine personnel might exceed the annual dose limit in high workload and poor radiation protection circumstances. Therefore, an accurate estimation of the annual dose limit is recommended. The goal of this research is to calculate the cumulative external effective dose (mSv) per year for nuclear medicine physicians, technologists, and nurses at SPECT/CT department. A total of 15 staff worked in the nuclear medicine department at King Saud Medical City (KSMC), Riyadh, Saudi Arabia were evaluated for the last six years. 99mTc is used more frequently for most of the patients. The procedures include renal, cardiac scintigraphy procedures. Staff dose was quantified using calibrated thermoluminecnt dosimeters (TLD-100) with an automatic TLD reader (Harshaw 6600). Exposure to ionizing radiation was evaluated in terms of deep doses (Hp(10) were evaluated. The overall average and standard deviation of the external doses for nuclear medicine physicians, technologists' and nurses were 1.8 ± 0.7, 1.9 ± 0.6, 2.0 ± 0.9, 2.2 ± 0.8, 6.0 ± 2.8, and 3.6 ± 1.3 for the years 2015,2016,2017,2018,2019, and 2020, respectively. Technologists and nurses received higher doses of compared to the nuclear medicine physicians. Technologists and nurses involved in radionuclide preparation, patients' injection, and image acquisition. Staff annual exposure is below the annual dose limits; however, this external dose is considered high compared to the current workload. • Staff annual effective dose was estimated at nuclear medicine department equipped with two SPECT/CT systems. • External effective dose in terms of Hp(10) was monitored for six consecutive years. • Occupational exposure was quantified with thermoluminecnt dosimeters (TLD-100). • Technologists and nurses received higher doses than the nuclear medicine physicians. • Staff annual radiation from external exposure is 50% below the annual dose limits. [ABSTRACT FROM AUTHOR]

In interventional radiology attendant staff can be exposed to significant doses from the radiation scattered from the patient, giving rise to heterogeneous energy distribution, exposure occurring over extended periods of time. Protection of staff is a prime concern, also including reducing the risk of carcinogenesis. With only limited published studies available, as in for instance in regard to lens opacifications, further evaluation of staff exposures and assessment of radiation protection techniques and measures are crucial. Present study has sought to evaluate staff radiation exposure in a radiology department that performs interventional procedures. Annual occupational exposures were obtained for 32 personnel (6 females and 26 males) in a radiology department at a tertiary hospital. Personal dose equivalent H p (d) was measured in terms of H p (0.07) (shallow dose) and H p (10) (deep dose). The measurements were made over a period of two consecutive years, 2017 and 2018, use being made of TLD-100 thermoluminescent dosimeters. In units of mSv, the corresponding average annual dose equivalent and range for H p (10) and H p (0.07) were 4.6 ± 7.0 (0.1–25.5) and 5.1 ± 7.3 (0.1–25.5). Notably, 16% of staff received doses that were greater than the annual dose limit. Since H p (10) offers a conservative evaluation of effective dose, evaluation of the working environment is necessary in seeking to ensure dose values remain below annual dose limits. • Occupational exposure was measured at interventional radiology department. • Personal dose equivalent (H p (d) were measured in terms of H p (0.07) (shallow dose) and H p (10) (deep dose) were evaluated. • Staff exposures were measured using TLD-100 thermoluminecent dosimeters. • 16% of the staff received doses that were greater than the annual dose limit. • Variation in staff dose is due to workload and type of the procedure. [ABSTRACT FROM AUTHOR]