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Saudi Medical Journal Sep 2022To evaluate the radiation metrics from frequently carried out vascular and interventional radiology (VIR) procedures at a tertiary care institution and compare them to...
OBJECTIVES
To evaluate the radiation metrics from frequently carried out vascular and interventional radiology (VIR) procedures at a tertiary care institution and compare them to international diagnostic reference levels (DRLs).
METHODS
A retrospective study of the radiation metrics of VIR-procedures carried out from January 2015 to December 2019. The collected data included age, gender, height and weight, reference point air kerma (mGy), dose area product (DAP; Gy.cm2), and fluoroscopy time (min.) The body mass index (BMI) and peak skin dose were calculated. The study cohort included 8942 adult patients (54.4% male, 45.6% female) with a mean age of 56.96 years and mean BMI of 26.86.
RESULTS
Transjugular intrahepatic portosystemic shunt (TIPS) creation recorded the highest mean fluoroscopy time of 69.41 min., followed by central venous recanalization 39.67min. TIPS creation had the highest mean DAP (1161.16 Gy.cm2), followed by trans arterial chemoembolisation (TACE) (500.63Gy.cm2). TIPS creation was associated with the highest peak skin dose (2766.81mGy), followed by TACE (1588.29mGy). Compared to other studies, TIPS creation and TACE are associated with significantly higher DAP.
CONCLUSION
Majority of VIR-procedures demonstrate no significant institutional variations in dosimetry compared to other studies. Using these studied values as reference levels may help identifying procedures that need quality control to minimize unnecessary exposures.
Topics: Adult; Female; Humans; Male; Middle Aged; Radiation Dosage; Radiography, Interventional; Radiology, Interventional; Retrospective Studies; Tertiary Healthcare
PubMed: 36104049
DOI: 10.15537/smj.2022.43.9.20220194 -
Journal of Medical Radiation Sciences Mar 2022The incidence of obesity has been steadily rising over the last few decades and is having a significant impact upon the health system. In radiography, a particular...
INTRODUCTION
The incidence of obesity has been steadily rising over the last few decades and is having a significant impact upon the health system. In radiography, a particular challenge of imaging obese patients is implementing the as low as reasonably achievable (ALARA) principle when determining radiation dose, and technical and patient-care adaptations. This study aimed to better understand the decision-making strategies of experienced radiographers in determining imaging and exposure factor selection in the context of imaging obese patients.
METHODS
This study employed a 'think-aloud,' methodology, and eight experienced diagnostic radiographers working in clinical education were recruited to perform routine AP abdominal X-ray projections on an anthropomorphic phantom. They were asked to simultaneously verbalise emerging thoughts as they considered positioning, exposure selection and image evaluation. This process was repeated with three different phantom sizes, each representing an increased BMI from 'healthy,' to, 'morbidly obese.' Audio recordings were transcribed and interpreted via Bowman's (1997) theory of radiographic judgement and decision-making.
RESULTS
Analysis of interview transcripts identified 12 key concepts considered by experienced radiographers. Differences in radiographic concepts were considered when imaging phantoms of different sizes was demonstrated. A shift from segmental (e.g. positioning) to more environmental factors (e.g. patient comfort) and an increase in the number of verbal considerations with increasing phantom size were identified. The shift in focus of decision-making stages identified the greater need to consider contextual factors such as patient comfort and repeatability when imaging obese patients.
CONCLUSION
Experienced radiographers find imaging obese patients challenging and alter their perception of image quality to accommodate for patient presentation. The findings will help inform future research, practice guidelines and learning resources to provide optimal imaging and care for obese patients, especially for student education.
Topics: Humans; Obesity, Morbid; Phantoms, Imaging; Radiation Dosage; Radiography, Abdominal
PubMed: 34496140
DOI: 10.1002/jmrs.543 -
Life Sciences in Space Research Nov 2021Energetic ion beam experiments with major space radiation elements, H, He, O, Si and Fe, have been conducted to investigate the radiation shielding properties of...
Energetic ion beam experiments with major space radiation elements, H, He, O, Si and Fe, have been conducted to investigate the radiation shielding properties of composite materials. These materials are expected to be used for parts and fixtures of space vehicles due to both their mechanical strength and their space radiation shielding capabilities. Low Z materials containing hydrogen are effective for shielding protons and heavy ions due to their high stopping power and large fragmentation cross section per unit mass. The stopping power of the composite materials used in this work is intermediate between that of aluminum and polyethylene, which are typical structural and shielding materials used in space. The total charge-changing cross sections per unit mass, σ, of the composite materials are 1.3-1.8 times larger than that of aluminum. By replacing conventional aluminum used for spacecraft with commercially available composite (carbon fiber / polyether ether ketone), it is expected that the shielding effect is increased by ∼17%. The utilization of composite materials will help mitigate the space radiation hazard on future deep space missions.
Topics: Cosmic Radiation; Heavy Ions; Polyethylene; Radiation Dosage; Radiation Protection; Space Flight; Spacecraft
PubMed: 34689952
DOI: 10.1016/j.lssr.2021.08.004 -
Spine Deformity Jul 2023Children are exposed to significant radiation doses during the investigation and treatment phases of scoliosis. EOS is a new form of low-dose radiation scan which also...
PURPOSE
Children are exposed to significant radiation doses during the investigation and treatment phases of scoliosis. EOS is a new form of low-dose radiation scan which also yields great image quality. However, currently its use is discouraged in the UK due to higher costs. We aimed to quantify the additional radiation dose and cancer risk.
METHODS
We retrospectively reviewed all paediatric cases who received both standing whole spine roentgenograms and EOS scans as part of their investigations for scoliosis during a six-month period. We compared the radiation doses between the two modalities and estimated the additional mean lifetime cancer risk per study.
RESULTS
We identified 206 children (mean age 14.4) who met the criteria of having both scans. Dose area products (dGycm) were converted to estimated effective doses (mSv). The total mean doses were 0.68 mSv (PA 0.49 + Lat 0.19) for plain films, and 0.13 mSv (PA 0.08 + Lat 0.04) for EOS scans (p < 0.001). Additional lifetime cancer risk of a plain film was 543% greater than EOS for both sexes (1/10727 versus 1/5827 in males, 1/34483 versus 1/6350 in females).
CONCLUSION
There is approximately 5.4-fold increase in risk of cancer for both boys and girls with roentgenograms over EOS, with girls being the most impacted. This carries a significant impact when considering the need for repeat imaging on additional lifetime malignancy risk in children. In our opinion, EOS dual planar scanning is the new gold standard when X-ray of the whole spine is required.
LEVEL OF EVIDENCE
III.
Topics: Male; Female; Child; Humans; Adolescent; Scoliosis; Retrospective Studies; Radiation Dosage; Neoplasms; Radiation Exposure
PubMed: 36947393
DOI: 10.1007/s43390-023-00653-6 -
Radiological Physics and Technology Mar 2023The COVID-19 pandemic has resulted in a large increase in the number of patients admitted to hospitals. Radiological technologists (RTs) are often required to perform...
The COVID-19 pandemic has resulted in a large increase in the number of patients admitted to hospitals. Radiological technologists (RTs) are often required to perform portable chest X-ray radiography on these patients. Normally, when performing a portable X-ray, radiation protection equipment is critical as it reduces the scatter radiation dose to hospital workers. However, during the pandemic, the use of a lead shield caused a heavy weight burden on workers who were responsible for a large number of patients. This study aimed to investigate scatter radiation doses received at various distances, directions, and positions. Radiation measurements were performed using the PBU-60 whole body phantom to determine scatter radiation doses at 100-200 cm and eight different angles around the phantom. The tests were conducted with and without lead shielding. Additionally, the doses were compared using the paired t test (p < 0.005) to determine suitable positions for workers who did not wear lead protection that adhered to radiation safety requirements. Scatter radiation doses of all 40 tests showed a highest and lowest value of 1285.5 nGy at 100 cm in the anteroposterior (AP) semi upright position and 134.7 nGy at 200 cm in the prone position, respectively. Correlation analysis between the dosimeter measurement and calculated inverse square law showed good correlation, with an R value of 0.99. Without lead shielding, RTs must stay at a distance greater than 200 cm from patients for both vertical and horizontal beams to minimize scatter exposure. This would allow for an alternative way of performing portable chest radiography for COVID-19 patients without requiring lead shielding.
Topics: Humans; Pandemics; COVID-19; Radiography; Radiation Protection; Radiation Dosage; Scattering, Radiation; Phantoms, Imaging
PubMed: 36656425
DOI: 10.1007/s12194-023-00698-2 -
Dento Maxillo Facial Radiology Feb 2023To present patient dose levels for different CBCT scanners, acquired by a dose monitoring tool in a University Hospital, as a function of field of view (FOV), operation...
OBJECTIVE
To present patient dose levels for different CBCT scanners, acquired by a dose monitoring tool in a University Hospital, as a function of field of view (FOV), operation mode, and patient age.
METHODS
An integrated dose monitoring tool was used to collect radiation exposure data [type of CBCT unit, dose-area product (DAP), FOV size, and operation mode] and patient demographic information (age, referral department) performed on a 3D Accuitomo 170 and a Newtom VGI EVO unit. Effective dose conversion factors were calculated and implemented into the dose monitoring system. For each CBCT unit, the frequency of examinations, clinical indications, and effective dose levels were obtained for different age and FOV groups, and operation modes.
RESULTS
A total of 5163 CBCT examinations were analyzed. Surgical planning and follow-up were the most frequent clinical indications. For the standard operation mode, effective doses ranged from 35.1 to 300 µSv and 9.26-117 µSv using 3D Accuitomo 170 and Newtom VGI EVO, respectively. In general, effective doses decreased with increasing age and FOV size reduction.
CONCLUSIONS
Effective dose levels varied notably between systems and operation modes.Operation mode selection and FOV size were indication-oriented, with larger FOV sizes election serving surgical planning and follow-up. Seeing the influence of FOV size on effective dose levels, manufacturers could be advised to move toward patient-specific collimation and dynamic FOV selection. Systematically monitoring patient doses could be recommended for steering future CBCT optimization.
Topics: Humans; Radiography, Dental; Phantoms, Imaging; Radiation Dosage; Cone-Beam Computed Tomography; Hospitals
PubMed: 36802857
DOI: 10.1259/dmfr.20220213 -
Journal of Radiation Research Mar 2022Intestinal organoids are an in vitro cultured tissue model generated from intestinal stem cells, and they contain a mixture of epithelial cell types. We previously...
Intestinal organoids are an in vitro cultured tissue model generated from intestinal stem cells, and they contain a mixture of epithelial cell types. We previously established an efficient 'one cell/well' sorting method, and defined organoid-forming potential (OFP) as a useful index to evaluate the stemness of individual cells. In this study, we assessed the response to radiation dose and dose-rate by measuring both OFP and the percentage of stem cells in the crypts. After high-dose-rate (HDR, 0.5 Gy/min) irradiation in vivo, the percentage of stem cells in the harvested crypt cells decreased, and the replenishment of cycling stem cells originating from dormant cells was enhanced, but OFP increased in cells irradiated with a total dose of >1 Gy. In contrast, at a total dose of 0.1 Gy the percentage of stem cells reduced slightly, but neither replenishment rate nor OFP changed. Furthermore, the response to 1 Gy of low-dose-rate (LDR) irradiation was similar to the response to 0.1 Gy HDR irradiation. These results suggest that 0.1 Gy HDR irradiation or 1 Gy LDR irradiation does not alter stemness. Additionally, the OFP increase in the colon in response to irradiation was smaller than that in the duodenum, similar to the percentage of stem cells. Understanding the differences in the response of stem cells between the colon and the duodenum to radiation is important to clarify the mechanisms underlying the development of radiation-associated intestinal cancers.
Topics: Dose-Response Relationship, Radiation; Intestines; Organoids; Radiation Dosage; Radiation, Ionizing; Stem Cells
PubMed: 34977948
DOI: 10.1093/jrr/rrab120 -
Asian Pacific Journal of Cancer... Aug 2023The use of relatively narrow fields has become necessary with the advent of intricate and accurate radiation therapy delivery dose to patients; therefore, small-field...
BACKGROUND
The use of relatively narrow fields has become necessary with the advent of intricate and accurate radiation therapy delivery dose to patients; therefore, small-field dosimetry faces several difficulties. Both dose calculations and measurements require to be performed with extra care, due to the uncertainty that might be increased by using such small field sizes.
MATERIAL AND METHODS
In this study, we investigated the effect of detectors size on the dosimetry of small fields [starting with radiation fields from (1cm x 1cm), (2cm x 1cm), and (3cm x 1cm)...etc., up to (4cm x 5cm) and (5cm x 5cm)]. We used the linear accelerator and different types of ionization chambers i.e. [Farmer FC65-P, CC13, and CC01 (pinpoint)] an addition to semiconductors i.e. (IBA Razor diode)], and we investigated all detectors to read the absorbed dose in water under the reference conditions (field 10cm x10cm, SSD 100cm and depth 10cm).
RESULTS
While measuring the absolute dose under reference conditions, all detectors had a non-significant difference of less than ±2%, except for the Razor diode, which showed a significant difference of ± 5%. On the other hand, when small fields were measured, we discovered a significant difference of 48%, compared to the Razor diode.
CONCLUSION
The Razor diode is more stable in small-field dosimetry than other detectors. Also, the Razor Diode is intended for relative dosimetry but, it shall not be used for absolute dose measurements.
Topics: Humans; Particle Accelerators; Water; Radiation Dosage; Radiotherapy
PubMed: 37642062
DOI: 10.31557/APJCP.2023.24.8.2757 -
Japanese Journal of Radiology Oct 2021To inspect personal dose as an interventional radiologist for 40 years, to assess the enforcement number of interventional radiology (IR), and to check for radiation...
OBJECTIVE
To inspect personal dose as an interventional radiologist for 40 years, to assess the enforcement number of interventional radiology (IR), and to check for radiation cataract.
MATERIALS AND METHODS
I evaluated my own effective dose, an equivalent dose to the lens of the eye (EDL), and the number of IR procedures between March 2019 and June 1979. I examined the lens in June 2019 as a radiologist for 40 years.
RESULTS
The accumulation dose was 0 mSv in 1979-88. During 1989-93, the right crystalline lens equivalence of the value dose was measured. During 1993-96, two badge items for the head, neck, and abdomen were present. Both were distributed, but attaching to the same part and reversing occurred frequently. The EDL of the recent 5 years has exceeded 100 mSv. No association with the number of IR procedures was recognized. Posterior subcapsular vacuoles (PSV) as the early changes of the radiation cataract were recognized as four on the left and one on the right.
CONCLUSION
It is important to get accustomed to film badge wearing, and the cancelation of making a mistake in the wearing part. Radiologists should check the PSV at a stage beyond a certain constant dose.
Topics: Lens, Crystalline; Occupational Exposure; Radiation Dosage; Radiation Exposure; Radiology, Interventional
PubMed: 34117984
DOI: 10.1007/s11604-021-01147-z -
Zeitschrift Fur Medizinische Physik Feb 2024The International Partner Agencies of the International Space Station (ISS) present a comparison of the ionizing radiation absorbed dose and risk quantities used to... (Comparative Study)
Comparative Study Review
The International Partner Agencies of the International Space Station (ISS) present a comparison of the ionizing radiation absorbed dose and risk quantities used to characterize example missions in lunar space. This effort builds on previous collaborative work that characterizes radiation environments in space to support radiation protection for human spaceflight on ISS in low-Earth orbit (LEO) and exploration missions beyond (BLEO). A "shielded" ubiquitous galactic cosmic radiation (GCR) environment combined with--and separate from--the transient challenge of a solar particle event (SPE) was modelled for a simulated 30-day mission period. Simple geometries of relatively thin and uniform shields were chosen to represent the space vehicle and other available shielding, and male or female phantoms were used to represent the body's self-shielding. Absorbed dose in organs and tissues and the effective dose were calculated for males and females. Risk parameters for cancer and other outcomes are presented for selected organs. The results of this intracomparison between ISS Partner Agencies itself provide insights to the level of agreement with which space agencies can perform organ dosimetry and calculate effective dose. This work was performed in collaboration with the advisory and guidance efforts of the International Commission on Radiological Protection (ICRP) Task Group 115 and will be presented in an ICRP Report.
Topics: Female; Humans; Male; Cosmic Radiation; Radiation Dosage; Radiometry; Space Flight; Spacecraft
PubMed: 38030484
DOI: 10.1016/j.zemedi.2023.10.005