Evaluation Of Radiation Dose Research Articles

Weight-bearing cone-beam CT with extensive coverage for volumetric imaging in adolescent idiopathic scoliosis: system implementation and initial validation.

The study aimed to introduce a novel imaging method that generates large-coverage, weight-bearing, and 3D images of the whole spine. The proposed system comprises an X-ray tube, a flat panel detector, and a standing platform. The standing platform rotates the imaged subject, allowing for the acquisition of serial fluoroscopic images from different angles which can be used to create 3D images. To increase the longitudinal coverage, we apply a segmental scanning pattern in which the imaged region is scanned in segments and stitched. To address the issue of data inaccuracy between the segments, redundant areas are set at margins of the segmental images, and registration and stitching algorithms are applied. We conducted validation experiments to evaluate radiation dose and image quality. The dose was evaluated using the volume CT dose index (CTDIvol). For image quality evaluation, we measured the low-contrast and spatial resolution. Additionally, we conducted a clinical study consisting of 30 volunteers with adolescent idiopathic scoliosis who were imaged by our method, and the images were subjectively assessed based on image noise, artifacts, anatomical coverage, diagnostic confidence, and overall quality. The CTDIvol was 1.23 mGy, and the low-contrast resolution was 0.6% at 4 mm and thespatial resolution was 8 lp/cm. The clinical images were generally of good quality, with high scores for all factors evaluated. Our method successfully generates large-coverage, weight-bearing, and 3D images of the whole spine with high image quality and low radiation dose. It shows potential for wider clinical applications for various musculoskeletal conditions.

Evaluation of institutional whole-body and extremity occupational radiation doses in nuclear medicine.

This study evaluated nuclear medicine occupational radiation doses at Sultan Qaboos University Hospital, a 700-bed tertiary care teaching hospital in Oman. Personal effective whole-body doses, Hp(10), and extremity doses, Hp(0.07), were collected for 19 medical radiation workers over a 7-year period (2015-2021). Personal doses for four professional groups were measured using calibrated thermo-luminescence dosemeters ((LiF:Mg,Ti) TLD-100). The average, median and maximum cumulative doses were compared against the annual whole-body and extremity dose limits (20mSv and 500mSv y-1, respectively) and local dose investigation level (DIL; 6mSv y-1). Personal whole-body doses (average:median:maximum) for technologists, medical physicists, nuclear medicine physicians and nurses were 1.8:1.1:7.8, 0.3:0.3:0.4, 0.1:0.1:0.2 and 0.1:0.1:0.2mSv, respectively. Personal extremity doses for left and right hand (average and maximum doses) follow similar trends. Average annual effective whole-body and extremity doses were well below the recommended annual dose limits. The findings suggest lowering local DIL for all staff except for technologists.

Assessment of soil-soil solution distribution coefficients of global fallout 237Np and 239Pu in Japanese upland soils

Neptunium-237 and 239Pu are important radionuclides in the safety assessment related to geological disposal of radioactive waste because of the possibility of long-term exposure to humans. Mobilities of these radionuclides in the environment are of particular importance for their radiation dose evaluation; therefore, in this study, we have made the assessment of the soil-soil solution distribution coefficient (Kd, L/kg) using global fallout 237Np and 239Pu in Japanese upland soils. The Kd values were determined by extracting these radionuclides from 24 soil samples using a laboratory batch method. The desorption Kd values of 237Np ranged from 3.3 × 102 to 1.0 × 104 L/kg, and their geometric mean (GM) and arithmetic mean (AM) were 1.7 × 103 L/kg and 2.6 × 103 L/kg, respectively. The desorption Kd values of 239Pu were found to vary from 9.4 × 103 to 7.1 × 104 L/kg, and their GM and AM were 3.3 × 104 L/kg and 4.0 × 104 L/kg, respectively. In Japanese upland soils, the Kd value of 239Pu was one order of magnitude higher than that of 237Np.

Fighting against COVID‐19: Innovations and applications

Fighting against <scp>COVID</scp>‐19: Innovations and applications

Investigation of the dosimetric properties of potassium hydrogen tartrate using EPR

Use of electron paramagnetic resonance (EPR) in radiation dosimetry means more accurate and reliable evaluation of radiation doses. The search for new dosimeter material is continuing to overcome some drawbacks of available ones. In current work potassium hydrogen tartrate is presented as a new EPR dosimeter material where its radiation dose dependency, effects of the change in microwave power and modulation amplitude on the peak-to-peak intensity were studied. Response of potassium hydrogen tartrate to gamma radiation was studied in two ranges: the first starts at 1.4 Gy and ends at 84.2 Gy, and the second from 42.1 Gy to 2415.6 Gy. Calibration curves were obtained with associated combined uncertainties range from 0.5% and up to 27.4% for the first peak and from 0.5% up to 10.2%, for the second peak. Calibration curves were plotted and compared to alanine. Time dependence of the EPR spectra of the radiation-induced radicals was monitored over short term (10 h) and long-term (28 days) following irradiation.

Evaluation of Radiation Dose in Close Proximity to the Patients after Myocardial Perfusion Scan and Related Factors

Evaluation of Radiation Dose in Close Proximity to the Patients after Myocardial Perfusion Scan and Related Factors

Evaluation of Radiation Dose to the Thyroid Gland on Infant Patients Undergoing Anteroposterior Chest X-Ray at a Tertiary Hospital in North-Western Nigeria

The study aims at measuring the entrance surface dose (ESD) of the thyroid gland of infant patients undergoing anterior-posterior (AP) chest x-ray in Usmanu Danfodiyo University Teaching Hospital Sokoto (UDUTHS). The study further determines the effective dose to the thyroid on infant patients undergoing AP chest x-ray. Also, compare the entrance surface dose of infant patients obtained from the study with other similar studies and diagnostic reference levels (DRLs) recommended by the International Commission on Radiological Protection ICRP. This is a prospective cross-sectional study and the primary source of data was obtained. Pediatric patients used for the study who are referred to the radiology department for an anteroposterior chest x-ray, UDUTH, Sokoto state, Nigeria. A non-probability sampling technique was adopted for the patient who came in for a chest x-ray (AP) and as recommended by ICRP that a minimum of 10 patients should be used to determine the ESD for each projection, therefore 15 patients were adopted for this study. The result of the ESD obtained for the thyroid on infant patients undergoing chest x-ray (AP) was averaged and the mean of the ESD was 1.38 mGy. This result was compared to similar studies done within the country and outside the country and with the European Commission on radiological protection as seen in Table 6 and Figure 3. The ESD obtained in this study is much higher than those obtained in similar studies as well as the recommended Diagnostic Reference Levels (DRLs). The method adopted in the study was recommended by the international commission on radiological protection, as a result of this, comparisons were reliably made with the reference values and similar studies. The result has shown that entrance surface doses and radiation doses to the thyroid exceed the permissible value in Usmanu Danfodiyo University Teaching Hospital (UDUTH) Sokoto.

Radiation dose during interventional cardiology procedures: portable C-arm vs. a new generation fluoroscopy system

IntroductionOccupational exposure to ionizing radiation poses health risks for veterinary interventionalists. There are limited veterinary studies evaluating radiation dose in the cardiac catheterization laboratory. The purpose of this study was to report direct radiation dose exposure to patients during common interventional cardiology procedures and compare these doses between two fluoroscopy units. AnimalsOne hundred and fifty-four client-owned dogs. Materials and MethodsPatient dose during procedures using a portable C-arm were retrospectively analyzed and compared to those performed in a contemporary interventional suite. Fluoroscopy equipment, procedure type, operator, patient weight, fluoroscopy time, dose area product, and air kerma were recorded and statistically modeled using univariable and multivariable linear regression to evaluate the effect of each factor. ResultsPatient dose population (154 dogs), comprised 61 patent ductus arteriosus occlusions, 60 balloon pulmonary valvuloplasties, and 33 pacemaker implantations. Patient dose was significantly lower in the group utilizing a newer generation fluoroscopy unit vs. the group utilizing an older portable C-arm, positively correlated with patient weight, and highest during balloon pulmonary valvuloplasties compared to patent ductus arteriosus occlusions or pacemaker implantations (all P<0.010). DiscussionNewer fluoroscopy systems can be equipped with technologies that improve image quality while reducing patient dose and radiation exposure to interventional personnel. ConclusionsWe documented a significant reduction in patient radiation dose using a newer fluoroscopy system as compared to an older portable C-arm for interventional cardiology procedures in animals. Improved knowledge of patient radiation dose factors may promote better radiation safety protocols in veterinary interventional cardiology.

Dose measurement study of the chest during a CT scan using a fabricated phantom

The purpose of this study was to evaluate radiation doses during computer tomography (CT) scans of the whole body and organs using a fabricated phantom. The Weighted Computer Tomography Dose Index (CTDIw) was evaluated and measured using a fabricated phantom, and five CT scanners were used for chest examinations from four hospitals in Najran, Saudi Arabia. The heart, lungs, esophagus, and spinal cord doses were measured with clinical whole body CT acquisition protocol using Thermoluminescent Dosimeters (TLDs). The TLDs used for measurements were selected for an accuracy of 5% and calibrated for the X-ray radiation field. The CTDIw and organ doses reported in this study were compared with results of ImPACT software for calculating organ doses. The results show good agreement with the calculations and the literature. The measured specific organ doses ranged between 1.33 mGy (lung marrow) and 1.65 mGy (esophagus). The model is easy to produce and useful for evaluating the organ doses and CTDIw.

Evaluation of Image Quality and Radiation Dose according to Use of the Tin Filter during CT Examination

The Tin Filter used in CT scans in medical field has the effect of reducing patient exposure without deteriorating the image quality by block in low-energy X-rays (ranging 30-50 keV) generated from CT scanners. In this study, chest low-dose CT scans were performed with the lungman phantom and various low-dose scan protocol. Then, the image quality of acquired images were evaluated by comparing the radiation dose as to the use of tin filter. The performed evaluation showed that when performing CT scans with a Tin filter installed, the exposure dose was considerably reduced by removing low energy X-rays, but SNR and CNR decreased slightly. Therefore, it is significantly considered that the use of a tin filter in CT scans will help reduce the exposure dose as well as the patient dose while maintaining image quality.

Comparing Radiation Dose of Cerebral Angiography Using Conventional and High kV Techniques: A Retrospective Study on Intracranial Aneurysm Patients and a Phantom Study.

Evaluation of patient radiation dose after the implementation of a high kV technique during a cerebral angiographic procedure is an important issue. This study aimed to determine and compare the patient radiation dose of intracranial aneurysm patients undergoing cerebral angiography using the conventional and high kV techniques in a retrospective study and a phantom study. A total of 122 cases (61 cases with conventional technique and 61 cases with high kV technique) of intracranial aneurysm patients, who underwent cerebral angiographic procedure and met the inclusion criteria, were recruited. The radiation dose and the angiographic exposure parameters were reviewed retrospectively. The radiation dose in the phantom study was conducted using nanoDotTM optically stimulating luminescence (OSLD), which were placed on the scalp of the head phantom, the back of the neck, and the phantom skin at the position of the eyes. The standard cerebral angiographic procedure using the conventional and high kV techniques was performed following the standard protocol. The results showed that the high kV technique significantly reduced patient radiation dose and phantom skin dose. This study confirms that the implementation of a high kV technique in routine cerebral angiography for aneurysm diagnosis provides an effective reduction in radiation dose. Further investigation of radiation dose in other interventional neuroradiology procedures, particularly embolization procedure, should be performed.

AAPM Task Group Report 238: 3D C-arms with volumetric imaging capability.

This report reviews the image acquisition and reconstruction characteristics of C-arm Cone Beam Computed Tomography (C-arm CBCT) systems and provides guidance on quality control of C-arm systems with this volumetric imaging capability.The concepts of 3D image reconstruction, geometric calibration, image quality, and dosimetry covered in this report are also pertinent to CBCT for Image-Guided Radiation Therapy (IGRT). However, IGRT systems introduce a number of additional considerations, such as geometric alignment of the imaging at treatment isocenter, which are beyond the scope of the charge to the task group and the report. Section 1 provides an introduction to C-arm CBCT systems and reviews a variety of clinical applications. Section 2 briefly presents nomenclature specific or unique to these systems. A short review of C-arm fluoroscopy quality control (QC) in relation to 3D C-arm imaging is given in Section 3.Section 4 discusses system calibration, including geometric calibration and uniformity calibration.A review of the unique approaches and challenges to 3D reconstruction of data sets acquired by C-arm CBCT systems is give in Section 5. Sections 6 and 7 go in greater depth to address the performance assessment of C-arm CBCT units. First, Section 6 describes testing approaches and phantoms that may be used to evaluate image quality (spatial resolution and image noise and artifacts) and identifies several factors that affect image quality.Section 7 describes both free-in-air and in-phantom approaches to evaluating radiation dose indices. The methodologies described for assessing image quality and radiation dose may be used for annual constancy assessment and comparisons among different systems to help medical physicists determine when a system is not operating as expected. Baseline measurements taken either at installation or after a full preventative maintenance service call can also provide valuable data to help determine whether the performance of the system is acceptable. Collecting image quality and radiation dose data on existing phantoms used for CT image quality and radiation dose assessment, or on newly developed phantoms, will inform the development of performance criteria and standards. Phantom images are also useful for identifying and evaluating artifacts. In particular, comparing baseline data with those from current phantom images can reveal the need for system calibration before image artifacts are detected in clinical practice. Examples of artifacts are provided in Sections 4, 5, and 6.

Vertical distributions of radionuclides along the tourist-attractive Marayon Tong Hill in the Bandarban district of Bangladesh.

This is the first attempt in the world to depict the vertical distribution of radionuclides in the soil samples along several heights (900 feet, 1550 feet, and 1650 feet) of Marayon Tong hill in the Chittagong Hill Tracts, Bandarban by HPGe gamma-ray spectrometry. The average activity concentrations of 232Th, 226Ra, and 40K were found to be 37.15 ± 3.76 Bqkg-1, 19.69 ± 2.15 Bqkg-1, and 347.82 ± 24.50 Bqkg-1, respectively, where in most cases, 232Th exceeded the world average value of 30 Bqkg-1. According to soil characterization, soils ranged from slightly acidic to moderately acidic, with low soluble salts. The radium equivalent activity, outdoor and indoor absorbed dose rate, external and internal hazard indices, external and internal effective dose rates, gamma level index, and excess lifetime cancer risk were evaluated and found to be below the recommended or world average values; but a measurable activity of 137Cs was found at soils collected from ground level and at an altitude of 1550 feet, which possibly arises from the nuclear fallout. The evaluation of cumulative radiation doses to the inhabitants via periodic measurement is recommended due to the elevated levels of 232Th.This pioneering work in mapping the vertical distribution of naturally occurring radioactive materials (NORMs) can be an essential factual baseline data for the scientific community that may be used to evaluate the variation in NORMs in the future, especially after the commissioning of the Rooppur Nuclear Power Plant in Bangladesh in 2024.

Optimisation of the CT pulmonary angiogram (CTPA) protocol using a low kV technique combined with high iterative reconstruction (IR): A phantom study

IntroductionThis study aims to optimise the current CTPA protocol at a public general hospital in Malta using lower kV combined with high Iterative Reconstruction (IR) (>50%). MethodsThe research consisted of a 2-phase anthropomorphic phantom study. Phase 1: radiation dose evaluation of 6 experimental protocols consisting of the low kV technique and high IR values and comparison with the current protocol. Phase 2: image evaluation. Objective image quality was evaluated in terms of contrast to noise ratio (CNR) and signal to noise ratio (SNR). Subjective image quality evaluation was performed by 3 radiologists undertaking Absolute Visual Grading Analysis (VGA). Resultant image quality scores were analysed using Visual Grading Characteristics (VGC). ResultsAll experimental protocols achieved significant (p < 0.05) dose reductions. SNR and CNR improved in almost all protocols, however, differences were not significant (p > 0.05). In subjective image quality analysis, the current protocol provided significant superior image quality (AUC > 0.5; p < 0.05) when compared to the experimental protocols consisting of 80 kV with 70%, 80%, 90% and 100% IR. The only two experimental protocols yielding comparable image quality to the current protocol were 80 kV with 50% IR (AUC: 0.195; p: 0.137) and 80 kV with 60% IR (AUC: 0.554; p: 0.624). The protocol yielding the greatest decrease in radiation dose being 80 kV with 60% IR. ConclusionsThe optimal IR value was 60%. When applying the optimal experimental protocol (80 kV combined with 60% IR), a significant dose reduction was achieved while maintaining diagnostic image quality. Implications for practiceThe low kV technique combined with high IR parameter is easily implemented and involves no additional cost and equipment.

Evaluation of radiation dose for inferior vena cava filter placement during pregnancy: A comparison of dosimetry and dose calculation software.

Numerous medical conditions are associated with pregnancy in women, including pulmonary thromboembolism, which can be fatal. An effective treatment of this condition is the positioning of an inferior vena cava filter (IVC-F) under the guidance of X-ray imaging. However, this procedure involves the risk of high radiation exposure to pregnant women and fetuses. Moreover, there are no published reports comparing the values of fetal dose, received during IVC-F placement in pregnant women, determined using dose calculation software and actual measurements. To address this issue, we compared the fetal radiation dose and entrance surface dose (ESD) for pregnant women for gestation periods of 6 and 9months based on software calculations and actual measurements. The ESD and fetal doses were estimated for a pregnant woman for gestation periods of 6 and 9months during IVC-F placement. For actual measurements, one pregnant model phantom was constructed using an anthropomorphic phantom, and two custom-made different-sized abdomen phantoms were used to simulate pregnancy. The custom-made abdomen phantoms were constructed using polyurethane. For software calculations, the software utilized a set of anatomically realistic pregnant patient phantoms. The ESD estimated using the software was consistent with the measured ESD, but the fetal dose estimations were more complicated due to fetal positioning. During fetal dose evaluation using software calculations, the user must carefully consider how much of the fetal length is in the irradiation field to prevent underestimation or overestimation. Despite the errors, the software can assist the user in identifying the magnitude of the dose approaching critical limits.

Evaluation of Radiation Dose in Computed Tomography Angiography before Transcatheter Aortic Valve Implantation

Objective: To investigate the effective radiation dose and image quality of computed tomography angiography (CTA) before transcatheter aortic valve implantation (TAVI). Material and Methods: This study involved 65 participants, diagnosed with aortic valve stenosis and examined with CTA before TAVI. The total mAs, kVp, volume CT dose index (CTDIvol), and dose–length product (DLP) in each scanning phase were recorded. The effective dose was calculated by multiplying the DLP by the conversion coefficient (k=0.015 mSv/[mGy.cm]). For quantitative image analysis, circular regions of interest were placed on six levels of the aorta in the axial images. The CT attenuation value, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured. For qualitative analysis, two radiologists rated the image quality of the aortic root and aortoiliac pathway. Results: The mean CTDIvol and DLP were 23.59±5.19 mGy and 881.01±193.41 mGy.cm., respectively. The mean effective dose was 13.22±2.90 mSv; the whole-aorta CTA phase received the highest dose, followed by the coronary CTA and coronary artery calcium scoring phases (9.62±2.60, 2.44±1.13, and 1.16±0.55 mSv, respectively). Image quality ranged from good to excellent in all segments of the aorta. Conclusion: The mean effective radiation dose of the pre-TAVI CT examination using 256-multidetector CT was 22.91± 5.03 mSv. The image quality in the aorta was good to excellent. The main factors that affected the radiation dose were: body mass index, total mAs, and kVp.

Evaluation of radiation doses of the 18FDG PET/CT hybrid imaging in adult and paediatric oncologic patients

Positron emission tomography associated with computed tomography (PET/CT) with 18 Fluoro-2-deoxy-D-glucose (18FDG) plays a key role in the management of oncological patients. Nevertheless, this hybrid PET/CT imaging exposes patients to dual irradiation: PET radiopharmaceuticals and CT X-rays.The aim of this study was to estimate and compare the contributions of 18FDG-PET and CT to the effective dose of this hybrid imaging, in oncologic patients. This study included 394 patients (357 adults and 37 children) aged 4–81 years.For the adult patients, the mean effective doses were 4 ± 1 mSv and 13 ± 5 mSv for PET and CT, respectively. The total effective dose was 17 ± 5 mSv. For the paediatric patients, the mean effective doses were 4.3 ± 1.1 mSv and 7 ± 3 mSv for PET and CT, respectively. The total effective dose was 11.5 ± 3.5 mSv. The mean contributions of CT to the effective dose of PET/CT examination were 75% for adults and 61% for children, respectively.Despite the importance of hybrid imaging, the percentage of contribution of CT remains very high. It is therefore essential to optimize the dose of the PET/CT protocol to keep the dose as low as reasonably achievable (ALARA).

Evaluation of Radiation Dose according to Aneurysm Size and Location during Cerebral Aneurysm Coil Embolization

Evaluation of Radiation Dose according to Aneurysm Size and Location during Cerebral Aneurysm Coil Embolization

관상동맥 CT 혈관조영술에서 ECG Window Acquisition 단위 변환을 통한 선량 및 화질 평가에 관한 연구

The purpose of this study was to evaluate radiation dose and image quality compared to those of the relative delay scan when using an absolute delay scan after converting the ECG window acquisition unit in coronary CT angiography. We used chest phantom and ECG simulator through the phantom study. Patient study was conducted on 90 sinus rhythm patients and 76 atrial fibrillation patients. The absolute delay scan was performed after unit conversion based on the average heart rate. After setting the region of interest, quantitative evaluation of image quality was made, qualitative evaluation was made by two observers. The dose was evaluated using the CTDIvol and DLP. There were no significant differences in quantitative values in terms of the phantom study. At an irregular heart rate 79, the CTDIvol of the experimental group decreased by 18% compared to the control group, the DLP decreased by 17.4% compared to the control group.(P&lt;0.05) As a result of patient study, there were no significant differences in quantitative values in terms of the patient study. The CTDIvol of the artrial fibrillation experimental group decreased by 33% compared to the control group, the DLP decreased by 30% compared to the control group.(P&lt;0.05) As a result, when examining coronary CT angiography of patients with atrial fibrillation, it will help reduce the patient’s dose without affecting the image quality if the scan range is set after converting the ECG window acquisition unit to milliseconds based on the average heart rate.

Pregnancy and medical radiation

IntroductionA non-negligible number of pregnant patients and radiation professionals are exposed to ionizing radiation for diagnostic and therapeutic purposes, each year. The lack or even the wrong information results in excessive stress and, in many cases unjustified termination of the pregnancy. Materials and methodsInternational Commission on Radiological Protection (ICRP) Publication 84 concerns the management of pregnant patients as well as pregnant workers in medical establishments where ionizing radiation is used. Based on the above report and the recent literature, this work discusses how to deal with these matters which are: Medically necessary radiation exposure of a pregnant woman, radiation-induced malformations, pre-conception radiation, handling of pregnant or probably pregnant patient in the hospital, absorbed dose to the fetus in Conventional and Interventional Radiology, Nuclear Medicine and Radiation Therapy, dose limits for pregnant workers, research involving pregnant women, termination of pregnancy. Results & discussionWe have shown that, the vast majority of conventional radiographic procedures and the majority of diagnostic procedures in nuclear medicine are at doses much lower than the exposure associated with fetal harm. In contrast, Radiation Therapy, multiple CT scans, certain therapies in nuclear medicine, and Invasive Radiology can potentially cause serious damage to the fetus. Termination of pregnancy depends on many medical, psychological and social factors.Specific goals of this work are to outline and evaluate the risks to the conceptus when exposed to radiodiagnostic and radiotherapeutic procedures during the various stages of pregnancy, to manage and evaluate radiation doses, to recommend means to control, and to evaluate communication issues with the pregnant patients.