Average Effective Dose Research Articles

Chest CT at X-Ray Dose Using a Noise-Mitigating Weighted Projection: The Thoracic Tomogram. Diagnostic Performance for Pneumonia Detection in Hemato-Oncology Patients.

To compare the diagnostic performance of a thick-slab reconstruction obtained from an ultra-low-dose CT (termed thoracic tomogram) with standard-of-care low-dose CT (SOC-CT) for rapid interpretation and detection of pneumonia in hemato-oncology patients. Hemato-oncology patients with a working diagnosis of pneumonia underwent an SOC-CT followed by an ultra-low-dose CT, from which the thoracic tomogram (TT) was reconstructed. Three radiologists evaluated the TT and SOC-CT in the following categories: (I) infectious/inflammatory opacities, (II) small airways infectious/inflammatory changes, (III) atelectasis, (IV) pleural effusions, and (V) interstitial abnormalities. The TT interpretation time and radiation dose were recorded. Sensitivity, specificity, diagnostic accuracy, ROC, and AUC were calculated with the corresponding power analyses. The agreement between TT and SOC-CT was calculated by Correlation Coefficient for Repeated Measures (CCRM), and the Shrout-Fleiss intra-class correlations test was used to calculate interrater agreement. Forty-seven patients (mean age 58.7 ± 14.9 years; 29 male) were prospectively enrolled. Sensitivity, specificity, accuracy, AUC, and Power for categories I/II/III/IV/V were: 94.9/99/97.9/0.971/100, 78/91.2/86.5/0.906/100, 88.6/100/97.2/0.941/100, 100/99.2/99.3/0.995/100, and 47.6/100/92.2/0.746/87.3. CCRM between TT and SOC-CT for the same categories were .97/.81/.92/.96/.62 with an interobserver agreement of .93/.88/.82/.96/.61. Mean interpretation time was 18.6 ± 5.4 seconds. The average effective radiation dose of TT was similar to a frontal and lateral chest X-ray (0.27 ± 0.08 vs 1.46 ± 0.64 mSv for SOC-CT; P < .01). Thoracic tomograms provide comparable diagnostic information to SOC-CT for the detection of pneumonia in immunocompromised patients at one-fifth of the radiation dose with high interobserver agreement.

A preliminary study on determination of radioactivity levels and estimation of the annual effective dose in dried fruits consumed in Albania.

This work aimed to support Albania's food safety monitoring regime. In this context, the natural and artificial radioactivity was measured in 20 samples of dried fruits collected randomly in different markets of Tirana. The activity concentration of 40K, 226Ra, 232Th and 137Cs was determined by using the high-purity germanium detector. The maximum values of activity concentration in dried fruits were calculated as 517±22Bqkg-1 for 40K, 11.10±0.93Bqkg-1 for 226Ra, 4.38±0.26Bqkg-1 for 232Th and 0.83±0.14Bqkg-1 for 137Cs. The average values of activity concentration of 40K and 226Ra were 269and 6.05Bqkg-1 and the average effective dose to individuals from the intake of the dried fruits was 44μSv y-1. All average values in this study were lower than recommended values by reports United Nations Scientific Committee on the Effect of Atomic Radiation, World Health Organization and International Commission on Radiological Protection for all age groups. Therefore, all dried fruit samples in this study are safe for consumption with acceptable radiological risk and none of them pose any significant radiological impact. The obtained data in this paper and information for levels of radioactivity and ingestion absorbed dose from dried fruits can be used to be the basic data for future comparative analysis of the other studies.

Evaluation of Natural Radioactivity Level in Surface Soil from Bambasi District in Benishangul Gumuz Region, Ethiopia.

The study assessed the concentration of natural radionuclides in soil samples from the Bambasi district in Ethiopia's Benishangul Gumuz region using a gamma-ray spectrometer equipped with a high-purity germanium (HPGe) detector. The measured activity concentrations of 238U, 232Th, and 40K in soil samples varied from 46.2 ± 2.25 to 88.49 ± 5.73 Bq/kg, 73.4 ± 4.12 to 119.65 ± 8.45 Bq/kg, and 176.78 ± 8.63 to 396.71 ± 25.39 Bq/kg, respectively. The average concentration of 238U and 232Th exceeded the recommended worldwide population weighted average values of 32.0 and 45.0 Bq/kg, respectively, while the average concentration of 40K was below the recommended value of 420.0 Bq/kg. The mean absorbed dose rate was calculated to be 91.6 ± 5.1 nGy/h, which is above the recommended safe value of 59 nGy/h. The average annual effective dose equivalents for indoor and outdoor exposure were determined to be 2.65 ± 0.14 mSv/y and 0.66 ± 0.1 mSv/y, respectively. The calculated mean values of the internal hazard index, external hazard index, and gamma index across all soil samples were 0.72 ± 0.05, 0.55 ± 0.02, and 0.72 ± 0.02, respectively, all below the recommended safe threshold of one. These findings suggest that the activity concentrations observed in the soil samples exceed safe levels, indicating the necessity for further investigation into radioactivity levels and epidemiological studies regarding potential hazards from high background radiation.

Результаты контроля радона в жилых домах вблизи разработки Шкурлатовского месторождения гранита

The presence of acting granite quarrying near the residential area may cause increase in indoor radon concentration. The paper presents results of estimating the level of radiation and carcinogenic danger for residents living near the acting Shkurlatov granite deposit. To assess average annual equivalent equilibrium volume activity (EEVA), Bq/m3, and the average annual individual effective radiation doses from radon isotopes presented in the indoor air, mSv/year, the data of the unified system for individual doses monitoring from 2017 through 2022 were used. Results of voluntary in-situ examination and 42 measures of radon volume activity in 17 residential buildings the closest to the granite quarry, were carried out in 2023. The above measures were used for calculation of EEVA of radon isotopes (Bq/m3) and the average annual individual effective radiation dose to the residents inhalated indoor radon (mSv/year). According to the data on radon monitoring in the dwellings situated near the Shkurlatov granite deposit the EEVA in wooden houses varied from 9.2 to 35.5 Bq/m3, EEVA in stone houses varied from 9.4 to 41.4 Bq/m3, average values are 21.22.0 and 21.91.8. The quoted values do not differ from the monitoring data in the Pavlovsk district of the Voronezh Region. Statistic data on malignant neoplasms incidence from 2017 through 2022 were investigated. As for the incidence of trachea, bronchus and lung cancer, no statistically significant difference between average multiyear cancer incidence in the area close to the Shkurlatov granite deposit in Pavlovsk district, Voronezh region, and in the more favorable district. The comparison was based on annual radiation doses due to radon isotopes inhalation. The results of the study suggest that radon at the registered indoor concentration does not affect cancer incidence among people living near the Shkurlatov granite deposit.

Evaluating internal exposure due to intake of 131I at a nuclear medicine centre of Dhaka using bioassay methods

Handling of radioisotopes may cause external and internal contamination to occupational workers while using radiation for medical purposes. This research aims to monitor the internal hazard of occupational workers who handle 131I. Two methods are used: in vivo or direct method and in vitro or indirect method. The in vivo or direct method was performed by assessing thyroid intake with a thyroid uptake monitoring machine. The in vitro or indirect method was performed by assessing urine samples with the help of a gamma-ray spectroscopy practice using a High-Purity Germanium (HPGe) Detector. In this study, fifty-nine thyroid counts and fifty-nine urine samples were collected from seven occupational workers who were in charge of 131I at the National Institute of Nuclear Medicine and Allied Sciences (NINMAS), Dhaka. The result showed that the average annual effective dose of seven workforces from thyroid counts were 0.0208 mSv/y, 0.0180 mSv/y, 0.0135 mSv/y, 0.0169 m Sv/y, 0.0072 mSv/y, 0.0181 mSv/y, 0.0164 mSv/y and in urine samples 0.0832 mSv/y, 0.0770 mSv/y, 0.0732 mSv/y, 0.0693 mSv/y, 0.0715 mSv/y, 0.0662 mSv/y, 0.0708 mSv/y.The total annual effective dose (in vivo and in vitro method) was found among seven workers in average 0.1039 mSv/y, 0.0950 mSv/y, 0.0868 mSv/y, 0.0862 mSv/y, 0.0787 mSv/y, 0.0843 mSv/y, 0.0872 mSv/y. Following the rules of the International Commission on Radiological Protection (ICRP), the annual limit of effective dose for occupational exposure is 20 mSv per year and the finding values from this research work are lesser than this safety boundary.

Examining External Dose Rates in Mamuju Regency, Indonesia: A Personal Radiation Dosimetry Approach

This study aimed to quantify the individual external radiation exposure in Mamuju, Indonesia. A SmartRad portable personal dosimeter was utilized for this purpose, and data was collected over a period of 30 days. The findings indicate that the dose rate varies from 0.152 to 4.200 μSv/h and cumulatively ranges from 0.1 to 8.4 μSv/day based on an average measurement duration of 160 minutes. The average dose rate in areas with mineral deposits is 11.02 mSv per year. In contrast, the average effective dose in areas without radioactive mineral deposits is 2.6493 mSv per year. The annual average effective dose for individuals was measured at 6.8347 mSv. These findings imply that personal exposure to radiation among the public in Mamuju exceeds the threshold recommended by the International Commission of Radiological Protection.

Assessing the parameters of electromagnetic fields and microclimate in the radionuclide department of the positron emission tomography centre

Currently, in the Russian Federation there is an increase in the number of positron emission tomography scans. As a result, the collective dose from radionuclide diagnostics in 2021 compared to 2020 increased by 62.0%, the average effective dose per one study in positron emission tomography (PET) centres of Moscow from 2015 to 2019. increased from 1.71 to 4.41 mSv. This leads to an increase in radiation doses not only for patients, but also for medical workers, and makes it urgent to develop modern effective measures to prevent the adverse effects of ionizing radiation.&#x0D; The aim of the study is to evaluate the parameters of electromagnetic fields and microclimate in the premises of the radionuclide department of the PET centre.&#x0D; During the study, in the main working areas of the radionuclide department, the following levels were assessed: the strength levels of electric and magnetic fields of industrial frequency, relative humidity, temperature and air speed using generally accepted measures in occupational hygiene.&#x0D; zThe main parameters of electromagnetic fields and microclimate (temperature, humidity, air speed) comply with hygienic standards in industrial workplaces. At the same time, in certain working areas of the radionuclide department, higher levels of electromagnetic fields were recorded, as well as a decrease in relative humidity and air velocity.&#x0D; Monitoring the parameters of electromagnetic fields and microclimate is important for improving the working conditions of medical workers in the radionuclide department of the PET centre, which helps maintain the functional state of workers at a high level, increases concentration and accuracy of movements, increases the speed of work manipulations, and reduces the time of contact with radionuclides when administered to patients and thereby reduce the dose load on health workers.&#x0D; Ethics. The study does not require the opinion of this committee.

Lifetime Attributable Breast Cancer Risk Related to Lung CT Scan in Women with Covid19

Abstract&#x0D; Purpose: Organ, effective dose, and Lifetime Attributable Risk (LAR) of breast cancer incidence related to lung Computed Tomography (CT) scans were evaluated. Seven hundred thirty-five female patients (20-50 years old) with Coronavirus (COVID-19) in four medical imaging centers in Tehran, Iran, were surveyed. Patients’ data, including age, sex, and exposure information (Kilovoltage (KVp), milliampere-second (mAs), pitch factor, Computed Tomography Dose Index (CTDIvol), and Dose Length Product (DLP)) were extracted from dose report pages in picture archiving and communication systems (PACS).&#x0D; Materials and Methods: Patients were divided into six age groups of 20-25, 25-30, 30-35, 35–40, 40-45, and 45–50 years. Breast, thyroid, lung, and heart absorbed doses, and also effective doses, were calculated by National Cancer Institute (NCICT) software, and LAR of breast cancer incidence has been evaluated by the Biological Effect of Ionizing Radiation (BEIR) VII in phase 2 report.&#x0D; Results: The average doses of breast, thyroid, lung, the heart were 3.97, 4.75, 4.10, and 3.37 mGy, respectively. Also, the average effective dose was 2.56 mSv. The average LAR of breast cancer in female patients was 7.45 per 100,000 exposures, decreasing dramatically with age. It was clear that exposure parameters and organ absorbed dose were significantly different between medical imaging centers (P value&lt;0.05).&#x0D; Conclusion: Although the CT scan is a useful instrument in the diagnosis of Corona disease, it should be suggested with caution due to the increased risk of breast cancer, especially in younger women and pediatrics. Also, low-dose CT scan protocols are recommended to minimize radiation effective and absorbed doses.

Analysis of radon concentrations in drinking water in coastal regions of Karnataka, South India.

The measurements of radon activity in water samples from several parts of Karnataka were studied. Drinking water quality is a routine tool in health and environmental research. Radon exposure puts the entire public at risk for radiological damage through inhalation and ingestion. Radon concentrations were measured using the emanometry technique. Estimated 222Rn activity concentration in water has been found to vary from 2.05 to 28.02Bql-1 with an average value of 7.38Bql-1. For all samples under study, the total average annual effective doses are much less than the safe limit of 100μSv y-1.

Estimation of natural radioactivity in the soil samples around the uranium site, royal village, Khandela, Sikar district, Rajasthan.

The measurements of activity concentration of radium ( 226Ra ), thorium ( 232Th) and potassium ( 40K ) natural radionuclides using high purity germanium ( HPGe ) detector to assess harmful effects on people residing around Royal Uranium Site, Sikar, Rajasthan, India. The activity concentrations range from 29.03±3.72 to 69.95±4.07Bq/kg for 226Ra with a mean value of 47.01Bq/kg, 57.99±6.13 to 113.94±6.54Bq/kg with a mean value of 86.56Bq/kg for 232Th,678.19±76.36 to 1426.55±81.32Bq/kg for 40K with a mean value of 1195Bq/kg. Average Radium Equivalent Activity was measured 261.59±35.48Bq/kg. The total outdoor absorbed gamma dose rate ranged from 78.42 to 157.91 nGy/h with a mean value of 122.12 nGy/h.The average annual effective dose equivalent outdoors and indoors was found 0.75mSv.Mean external (Hex) and internal (Hin) hazard indices are measured 0.70 and 0.82, respectively, for the study area.

Comparison of effective doses for personnel performing flaw detection in stationary conditions and &lt;i&gt;in situ&lt;/i&gt;

Official data on radiation doses for flaw detectors do not take into account working conditions. In the reporting forms, there is no division between personnel performing flaw detection in stationary conditions and in situ, which roughly averages the values of effective doses towards underestimating the values for personnel working in site radiography. In this work, comparison of our own data on radiation doses of flaw detectors was performed. It has been shown that the difference in the mean and median values of effective doses reaches 10 times. When performing flaw detection in stationary conditions, the personnel are at a sufficient distance from the source of ionizing radiation and are well shielded by engineering protective equipment, so the exposure is fairly uniform. In such cases, one individual thermoluminescent dosimeter located at chest level is sufficient to estimate the effective dose. The average annual effective dose for personnel conducting flaw detection in stationary conditions is 0.87 mSv (median – 0.88 mSv, maximum value – 0.99 mSv). During individual radiation monitoring of personnel performing flaw detection in situ using portable roentgen flaw detectors, cases of neglect in the use of individual dosimeters were identified, which requires more stringent measures to comply with existing requirements for ensuring radiation safety and operating rules for individual dosimeters. The average annual effective dose for flaw detectors working with portable roentgen flaw detectors is 9.03 mSv (median – 8.85 mSv, maximum value – 12.37 mSv).

Establishment of an institutional diagnostic reference level for vascular lower extremity computed tomography angiography

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.

Establishment of a local diagnostic reference level for computed tomography chest and abdomen in two different cities in Saudi Arabia

Background and aimSpiral computed tomography (CT) scans, which are considered a high-contrast resolution, quick and cross-sectional imaging technique, have grown in popularity as a result of technological advancements. However, these advancements have brought with them the potential for significantly increased radiation doses to the patient. Consequently, many organizations recommended optimization and establishing diagnostic reference levels. The aim of the current study was to assess CT radiation dose and propose a local diagnostic reference level (LDRL) for the adult trunk [chest and abdomen] using CT dose parameters such as CT dose index volume (CTDIvol) and dose length product (DLP) as well as to compare the practices for aforementioned examinations between two hospitals in Taif and Abha cities in Saudi Arabia. Materials and methodsData from 428 patients (216 for abdomen and 212 for chest) who were examined in two hospitals in Taif and Abha City in Saudi Arabia from December 2022 to March 2023, are used in this study. The data for hospitals in Taif and Abha are presented as ‘T’ and ‘A’ throughout this manuscript. The parameters of exposure and slice thickness were recorded in a specially designed data sheet together with the gender, age and patients morphometric. Microsoft Excel version 2010 was used to analyze results and plot the figures. The LDRL was achieved from the third quartile of CTDIvol and DLP for each hospital and examination. ResultsThe average DLP (mGy-cm) and CTDIvol (mGy) for the chest and abdomen were 243 mGy cm, 5.8 mGy and 549 mGy cm, 8.6 mGy respectively. The average effective dose (ED) for chest and abdomen were 5.10 and 21.10 mSv, respectively. The proposed LDRL for the chest and abdomen were 6.9 mGy (CTDIvol), 375 mGy-cm (DLP), 7.8 mGy (CTDIvol), and 747 (DLP) mGy-cm, respectively. ConclusionHospital ‘A’ irradiated patients with a higher dose for the abdomen exam than Hospital ‘T’, but both hospitals agreed on the amount of radiation dose received by patients for chest imaging. The proposed LDRL for two examinations was less than the DRL obtained from the literature.

The activity of 210Pb in cigarette smoked in Kazakhstan.

The radon decay product 210Pb is a known component of tobacco. In this study, the activity concentration of 210Pb in the most popular cigarette brands (six samples) for Kazakhstan consumers was determined by beta spectrometry. The activity levels of 210Pb ranged between 2.69 ± 0.27 and 27.42 ± 2.74mBq per cigarette. Higher activity concentrations for 210Pb were found in Sample No.4 and showed an excess of the world average by 1.8 times. The average activity concentrations of 210Pb in cigarette tobacco were 10.42 ± 1.04mBq cig-1. The daily activities inhaled in the lungs of a smoker, and the resulting effective doses due to cigarette smoking were calculated. Effective doses per year due to cigarette smoking were calculated assuming that 42.13% of the 210Pb in tobacco were retained in the lungs of the smokers. It is concluded that for a smoker in Kazakhstan, the average effective dose ranges from 9.1 ± 0.9 μSv/year to 92.8 ± 9.3 μSv/year for a cigarette consumption of one pack of cigarettes per day. The results indicate that the annual effective doses from inhalation of 210Pb due to smoking one pack of cigarettes per day are from 7 to 58 times (for different types of cigarettes) greater than the annual effective doses from ingestion of radionuclides via the diet.

Comparison of screw placement guided by O-arm navigation and ultrasound volume navigation in minimally invasive transforaminal lumbar interbody fusion

To compare the effectiveness of O-arm navigation and ultrasound volume navigation (UVN) in guiding screw placement during minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery. Sixty patients who underwent MIS-TLIF surgery for lumbar disc herniation between June 2022 and June 2023 and met the selection criteria were included in the study. They were randomly assigned to group A (screw placement guided by UVN during MIS-TLIF) or group B (screw placement guided by O-arm navigation during MIS-TLIF), with 30 cases in each group. There was no significant difference in baseline data, including gender, age, body mass index, and surgical segment, between the two groups ( P>0.05). Intraoperative data, including average single screw placement time, total radiation dose, and average single screw effective radiation dose, were recorded and calculated. Postoperatively, X-ray film and CT scans were performed at 10 days to evaluate screw placement accuracy and assess facet joint violation. Pearson correlation and Spearman correlation analyses were used to observe the relationship between the studied parameters (average single screw placement time and screw placement accuracy grading) and BMI. The average single screw placement time in group B was significantly shorter than that in group A, and the total radiation dose of single segment and multi-segment and the average single screw effective radiation dose in group B were significantly higher than those in group A ( P<0.05). There was no significant difference in the total radiation dose between single segment and multiple segments in group B ( P>0.05), while the total radiation dose of multiple segments was significantly higher than that of single segment in group A ( P<0.05). No significant difference was found in the accuracy of screw implantation between the two groups ( P>0.05). In both groups, the grade 1 and grade 2 screws broke through the outer wall of the pedicle, and no screw broke through the inner wall of the pedicle. There was no significant difference in the rate of facet joint violation between the two groups ( P>0.05). In group A, both the average single screw placement time and screw placement accuracy grading were positively correlated with BMI ( r=0.677, P<0.001; r=0.222, P=0.012), while in group B, neither of them was correlated with BMI ( r=0.224, P=0.233; r=0.034, P=0.697). UVN-guided screw placement in MIS-TLIF surgery demonstrates comparable efficiency, visualization, and accuracy to O-arm navigation, while significantly reducing radiation exposure. However, it may be influenced by factors such as obesity, which poses certain limitations.

Assessment of extremity dose for medical staff involved in positron emission tomography/computed tomography imaging: Retrospective study.

There has been an increase in positron emission tomography (PET)/computed tomography (CT) imaging procedures, and medical workers involved in PET/CT are at increased risk of occupational exposure. Data on extremity dose exposure are limited globally. The current study aimed to evaluate the occupational radiation dose for extremities for medical workers (nurses, radiographers/radiologic technologists, and nuclear medicine physicians) working in PET/CT scanners at 5 large hospitals in Turkey. Optically stimulated luminescence (OSL) and Thermoluminescent dosimeter (TLD) ring dosimeters were used to measure equivalent dose values. Hospitals 1, 2, and 5 used OSL, and 3 and 4 used TLD. A total of 502 readings were obtained from 55 workers. In millisievert (mSv), the average annual effective dose for all workers was 14.5 ± 17.7 (0.2-157.2). A radiography technologist received a maximum dose of 157.21. Nurses received the highest average annual effective dose (15.2 ± 19.46) (0.32-65.58), followed by radiography technologists (14.7 ± 18.03) (0.4-157.2), and nuclear medicine physicians demonstrated the least dose (8.6 ± 10.5) (1.2-24.4). The results show that the extremity dose is well below the annual dose limit of 500 mSv. However, there is a wide variation in dose among the workers, underlining a need for careful assessment of working conditions to ensure safe practices for all workers.

Assessment of the Radiation Situation and the Presence of Heavy Metals in the Soil in the Poleski National Park

The aim of the research in the Poleski National Park was to determine the concentration of radionuclides and heavy metals in the soil and to evaluate the absorbed dose and the average annual effective dose as a result of external exposure to ground-based radiation sources. The spread of anthropogenic radionuclide concentration in the Poleski National Park was the highest. This is a first-of-its-kind study in Poland. The annual effective dose calculated for the Poleski National Park was over three times higher than the average worldwide value. Soil samples were subjected to mineralization using a TITAN MPS with a rotor. Subsequently, the metals in the obtained solutions were determined using the atomic absorption spectrometry method with flame atomization (AAS FM). The content of copper Cu, nickel Ni, lead Pb, cadmium Cd, and chromium Cr did exceed the average content neither in Europe nor around the world. The soils of the Poleski National Park are characterized by pollution with the tested heavy metals, especially cadmium Cd.

PEMANTAUAN DOSIS RADIASI PADA CT SCAN UNTUK MENGETAHUI PERSENTASE POTENSI KANKER DI RSUD DR. MOH SALEH PROBOLINGGO

CT Scan is a diagnostic tool that helps identify body disorders without surgery. It works by using X-ray radiation to create images of the body. However, X-rays can be harmful to the human body. This study aims to determine the amount of radiation exposure associated with a CT scan and the potential cancer risk from this exposure. The study analyzed 1396 scans, including 1046 scans of the head, 128 scans of the thorax, and 221 scans of the abdomen, using contrast and non-contrast techniques. The effective dose was calculated by multiplying the Dose Length Product (DLP) by the organ weight factor. The study found that the abdomen had the highest average effective dose of radiation exposure, at 18.78 mSv, followed by the thorax at 5.72 mSv and the head at 2.20 mSv. The study also found a positive, strong, and significant relationship (p=0.000) between effective dose and the potential risk of cancer, with a ratio of 0.9966. The highest risk of cancer was associated with exposure in the abdomen, at 0.094%. The effective dose information can help patients, healthcare workers, and families understand the potential risks associated with CT scans and can be used as a tool for education. Keywords: CT Scan, DLP, effective dose, radiation risk, cancer potential.

Evaluation of effective dose for gamma-rays of terrestrial gamma-ray flashes in aviation: spectral- and atmosphere-effects

Terrestrial Gamma-ray Flashes (TGFs) are intense and fast gamma-ray emissions, energy up to 100 MeV, generated within the Earth's atmosphere at altitudes below 20 km. Satellite observations indicate the TGFs are not a rare phenomenon, being produced on average at one per thunderstorm, yielding a global production rate of ≈35 TGFs/min within a latitude band of ±38°. Furthermore, the TGFs may coincide with the flight altitudes for several commercial aircraft routes, typically within the 10−14 km range, and thus cause passengers/crews unexpected exposure to large fluxes of high-energy ionizing radiation, namely for distances of the order of km.Herein, we introduce a novel approach based on a simple analytic/numeric methodology to estimate the TGFs gamma-ray emissions effective doses based on the differential fluence of photons at aircraft altitude and tabulated effective dose conversion coefficients versus the photon energy. For the first time, we examine the effective dose dependence on TGF's gamma-ray energy spectrum models found in literature and the atmosphere mass thickness crossed by the gamma-rays. Additionally, since the real irradiation geometry of the whole body in aircraft might be a combination of the several idealized geometries used in radiation protection, we considered beyond the typical anteroposterior (AP), the posteroanterior (PA), and the rotational (ROT) geometries as representative irradiation geometries in exposure to TGF gamma-ray's emissions.We calculated the effective dose versus the distance between the TGF site and the aircraft altitude (12.5 km) within the 0.1−5.0 km range and atmosphere mass thickness within the 3.3−213 g cm−2 range. Additionally, we calculated the average effective dose per fluence versus the atmosphere mass thickness crossed by the gamma-rays. At a distance of 1 km (34 g cm−2) and for the typical exponential cut-off power-law model (α = 1, EC = 7.3 MeV), the effective dose was within the 0.18−0.19 mSv range, being the respective average effective dose per fluence within the 10.8−11.6 pSv cm2 range. Moreover, for the variant of the exponential cut-off power-law model (α = 1, EC = 7.3 MeV, Emin = 1 MeV), the effective dose was within the 0.42−0.46 mSv range, being the respective average effective dose per fluence at 34 g cm−2 within the 12.7−13.6 pSv cm2 range.Generally, the data obtained agree with the scarce data found in the literature for similar conditions, evidencing the effect of the parameterization of the TGFs gamma-rays energy models, which may result in a 2- to 10-fold effective dose escalation. For the typical exponential cut-off power-law model (α = 1, EC = 7.3 MeV), the data obtained for an aircraft that passes through the vicinity of one TGF, with a distance of 1 km, points to an increase of the aircraft crew and passengers' doses of few tenths mSv over the cosmic radiation dose of few tens μSv along a typical flight of 6 h duration, representing ≈20% and ≈1% of the ICRP-2007 annual reference levels for passengers (1 mSv) and aircraft crew (20 mSv), respectively. More, with a distance of 0.5 km, the effective dose value is comparable with the annual dose for the aircraft crew due to the cosmic radiation for a typical yearly flight time of 500 h, representing ≈130% and ≈7% of the ICRP-2007 annual reference levels for passengers and aircraft crew, respectively.

99mTc-Labeled FAPI SPECT Imaging in Idiopathic Pulmonary Fibrosis: Preliminary Results.

Idiopathic pulmonary fibrosis (IPF) is associated with a poor prognosis, presenting the most aggressive form of interstitial lung diseases (ILDs). Activated fibroblasts are crucial for pathological processes. Fibroblast activation protein (FAP) inhibitor (FAPI) tracers would be promising imaging agents for these diseases. The purpose of this study was to evaluate a 99mTc-labeled FAPI tracer, 99mTc-HFAPI imaging in IPF patients. Eleven IPF patients (nine males and two females; age range 55-75 year) were included in this pilot study. 99mTc-HFAPI serial whole-body scintigraphy at 5 min, 20 min, 40 min, 1 h, 2 h, 3 h, 4 h, and 6 h was acquired for dynamic biodistribution and dosimetry estimation in seven representative patients. SPECT/CT tomography fusion imaging of the chest region was performed in all patients at 4 h post-injection, which was considered as the optimal acquisition time. Dosimetry was calculated using OLINDA/EXM software (version 2.0; HERMES Medical Solutions). The quantified or semi-quantified standardized uptake values (SUVs) and lesion-to-background ratios (LBRs) of affected lung parenchyma were also calculated. The high-resolution CT (HRCT) stage was determined with visual evaluation, and the total HRCT score of each patient was measured using a weighting factor formula. Pulmonary function tests (PFTs) were recorded as well. Then, the relationships between the 99mTc-HFAPI results, disease extent on HRCT, and PFT results were investigated. Normal physiological uptake of 99mTc-HFAPI was observed mainly in the liver, intestinal tract, pancreas, gallbladder, and to a lesser extent in the spleen, kidneys, and thyroid, with no apparent retention in the blood circulation at the late time point. The mean injected activity of 99mTc-HFAPI was 813.4 MBq (range 695.6-888.0 MBq). No subjective side effects were noticed. The average whole-body effective dose was 0.0041 mSv/MBq per patient. IPF patients exhibited elevated pulmonary 99mTc-HFAPI uptake in abnormal lung regions, which was correlated with fibrotic regions on HRCT. Among different HRCT stage groups, both SUVmax and LBR showed significant differences (p < 0.001). The higher HRCT stage demonstrated significantly higher SUVmax and LBR. A linear correlation between 99mTc-HFAPI uptake and total HRCT score was observed for SUVmax (r = 0.7839, F = 54.41, p = 0.0094) and LBR (r = 0.7402, F = 56.33, p = 0.0092). 99mTc-HFAPI uptake also had moderate correlations with PFT results. Our preliminary data show that the 99mTc-HFAPI SPECT imaging is a promising new imaging modality in IPF patients. Investigations of its clinical value in monitoring disease progression and treatment response are needed in the future.