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X-ray guided procedures are being performed by an increasing variety of medical specialties. Due to improvements in vascular transcatheter therapies, there is an increasing overlap of imaged anatomy between medical specialties. There is concern that non-radiology fluoroscopic operators may not have sufficient training to be well informed of the potential implications of radiation exposure and mitigation strategies to reduce dose. This was a prospective, observational, single center study to compare occupational and patient dose levels when imaging different anatomical regions during fluoroscopically guided cardiac and endovascular procedures. Occupational radiation dose was measured at the level of the temple of 24 cardiologists and 3 vascular surgeons (n = 1369), 32 scrub nurses (n = 1307) and 35 circulating nurses (n = 885). The patient dose was recorded for procedures (n = 1792) performed in three angiography suites. Abdominal imaging during endovascular aneurysm repair (EVAR) procedures was associated with a comparatively high average patient, operator and scrub nurse dose despite additional table-mounted lead shields. Air kerma was relatively high for procedures performed in the chest, and chest + pelvis. Higher dose area product and staff eye dose were recorded during procedures of the chest + pelvis due to the use of digital subtraction angiography to evaluate access route prior to/during transaortic valve implantation. Scrub nurses were exposed to higher average radiation levels than the operator during some procedures. Staff should be cognizant of the potentially higher radiation burden to patients and exposed personnel during EVAR procedures and cardiac procedures using digital subtraction angiography. [ABSTRACT FROM AUTHOR]

The Computed Tomography Dose Index (CTDI) is an indicator for dose management in computed tomography (CT), but has limited use for patient dosimetry. To evaluate the patient dose, the size-specific dose estimate (SSDE), reported by the American Association of Physics in Medicine task groups 204, 220, and 293, must be calculated by the CTDIvol(z) displayed on the CT console, and the conversion factor f(D(z)) from the effective diameter (DEff) or water equivalent diameter (Dw). However, no reports have verified the appropriateness of using the 320-mm diameter phantom for dose assessment in CT examinations involving the lower limbs. Therefore, we validated a new method for evaluating the SSDE(z) of the lower limbs, using two 160-mm diameter phantoms instead of the 320-mm diameter phantom. The CTDIvol(z) obtained from Monte Carlo (MC) simulation study was reliable because they were almost the same as obtained in a dosimetry study. The conversion factor f (D (zl.l.)) for the lower limbs was evaluated based on the CTDIvol(z) obtained by MC simulation performed using two polymethyl methacrylate cylinder phantoms of 160-mm diameter. The MC simulation was performed by the International Commission on Radiological Protection publication 135 reference adult phantom and was used to evaluate the absorbed dose of the pelvis, thighs, knees, and ankles. The dose showing the greatest difference was the thighs, which was 8.3 mGy (16%) lower than the absorbed dose. Thus, the SSDE (zl.l.) could be estimated from the CTDI vol 320 z displayed on the CT scanner console. [ABSTRACT FROM AUTHOR]

We propose determining the entrance surface air kerma (ESAK) from the kerma area product (PKA) in digital radiology. ESAK values were derived from the X-ray tube outputs and patient exposure factors across five X-ray departments. Using linear regression between ESAK and PKA values, the slope and intercept coefficients were determined for each X-ray equipment and procedure. The method was examined using the data collected from patients who underwent chest PA/LAT, abdomen, pelvic AP, and lumbar spine AP/LAT X-ray examinations. The results showed a highly significant correlation between ESAK and PKA values and correlation coefficients, ranging from 0.77 to 1 with P-value < 0.001 in most studies. This method can be employed by incorporating dose data and related parameters into the X-ray device's software, similar to other dose-displayed information. The online determination of ESAK from PKA could help with quality assurance and patient dose management in digital radiology. [ABSTRACT FROM AUTHOR]

Objectives: The diagnostic reference level (DRL) is a useful tool for the optimisation of medical exposures. Thus, a Working Party coordinated by the Italian National Institute of Health and the National Workers Compensation Authority has been formed to provide Italian DRLs, for both diagnostic and interventional procedures, to be used as appropriate for the implementation of the 2013/59 European Directive into the national regulation. Materials and methods: The multidisciplinary Working Party was formed by professionals involved in diagnostic and interventional radiology medical exposures and started from a critical revision of both the literature and the results of previous Italian surveys. The procedures were divided into five sections for adult (projection radiography, mammography, diagnostic fluoroscopy, CT and interventional radiology) and two sections for paediatric patients (projection radiography and CT). The provided DRL values have been identified for "normal" adult patients and for age-classes of paediatric patients. Results: Some of the DRL values provided by the Working Party are reported in this study as an example, divided by adult/paediatric patients, radiological technique and examination: specifically, DRLs for new radiological practices and new dose quantities as DRLs metric were introduced. The median value (rather than the mean) for each procedure, derived from a sample of patients, has to be compared with the corresponding DRL value, and dosimetric data related to a minimum number of patients should be collected for each examination. Conclusions: The approach to the definition and use of DRLs through guidelines of national Authorities in collaboration with scientific Associations should simplify the periodical updating and could be useful for keeping the optimisation of medical exposures faithful to the development of radiological practice. [ABSTRACT FROM AUTHOR]

Digital radiography is gaining popularity among general dental practitioners. It includes digital intraoral radiography, digital panoramic radiography, digital cephalography, and cone-beam computed tomography. In this study, we focused on the methods to assess image quality of these techniques, except for digital cephalography, in the light of historical issues. We stressed on the importance of the development of a standardized phantom and quantitative analysis of diagnostic image quality using it, especially in the aspect of psychophysical properties of these digital systems. There is no missing link in the image quality assessment in digital intraoral radiography and cone-beam computed tomography in dental use. However, there are missing links between physical and diagnostic image qualities in panoramic radiography. The development of a semi-standardized phantom and the corresponding quantitative analysis method for image quality may be required in digital panoramic radiography. Quantitative image quality assessment using a standardized phantom will also be promising in the future artificial intelligence era. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the patient and the neurointerventionalist radiation dose levels during endovascular treatment of acute ischemic stroke, and to analyze factors affecting doses.Materials and Methods: From October 2017 to January 2019, we prospectively collected patient radiation data and neurointerventionalist data from real-time dosimetry from all consecutive thrombectomies. Multivariate analysis was performed to analyze patient total dose area product (DAP) and neurointerventionalist dose variability in terms of clinical characteristics and the technical parameters of thrombectomies. Local dose reference levels (RL) were derived as the 75th percentile of the patient dose distributions.Results: A total of 179 patients were treated during the study period and included in this study. Local dose RL for thrombectomy was derived for total DAP to 34 Gy cm2, cumulative air kerma of 242 mGy and fluoroscopy time of 12 min. The mean neurointerventionalist dose for thrombectomy was 7.7 ± 7.4 µSv. Height (P = 0.018), weight (P = 0.004), body mass index (P = 0.015), puncture to recanalisation (P < 0.001), fluoro time (P < 0.001), number of passes (P < 0.001), thrombolysis in cerebral infarction 2b/3 recanalisation (P = 0.034) and aspiration thrombectomy (P < 0.001) were independent factors affecting patient total DAP, whereas baseline National Institutes of Health Stroke Scale (P = 0.043), puncture to recanalisation (P = 0.003), fluoroscopy time (P = 0.009) and number of passes (P = 0.009) were factors affecting the neurointerventionalist dose.Conclusion: New reference patient doses lower than those in previously published studies were defined. However, the operator's doses were higher than those in the only available study reporting on operator's dose during cerebral interventions. [ABSTRACT FROM AUTHOR]

Background: There has been a year on year increase in imaging requests at our academic institution. The iRefer guidelines are produced by the Royal College of Radiologists in the UK and are designed to prevent inappropriate imaging and radiation exposure. They have been available to general practitioners and hospital physicians in Ireland since March 2015. Aims: Our aims were to determine the proportion of inappropriate imaging referrals pre- and post-guideline introduction and to calculate the cost and dose estimates for inappropriate scans. Methods: A retrospective review of 1124 radiographs was performed with reference to a validated audit template. Emergency department, in-patient, and general practitioner referrals were reviewed. Cost and cumulative dose estimates were calculated for inappropriate referrals taking into account salaries, average time spent performing/reporting radiographs, and median effective dose values. Results: The introduction of the iRefer guidelines has not significantly affected the proportion of inappropriate radiograph referrals at our institution, 42% pre-introduction and 43% post-introduction. We identified 784 inappropriate referrals across 6 radiograph subtypes, imparting a total median effective dose of 65.1 mSv to patients. The time spent performing inappropriate abdominal and spinal radiographs in 2017 yielded an estimated cost of €8036.40. Conclusion: A significant amount of inappropriate radiographs continue to be requested and performed, exposing patients to needless ionizing radiation and wasting staff members time at a financial cost. Interventions are needed to decrease inappropriate referrals. [ABSTRACT FROM AUTHOR]

Purpose: Technological advancements have greatly expanded the field of cardiac electrophysiology, requiring greater demands on imaging systems and potentially delivering higher radiation doses to patients and operators. With little contemporary research on occupational and patient radiation risk in the electrophysiology laboratory, the aim of this study was to analyze radiation doses, including occupational fetal doses, over approximately the last decade. We benchmarked the occupational data to our patient radiation dose data to allow for comparison and to put into perspective the associated radiation risks.Methods: Occupational radiation dosimetry analyzed included data from an 11-year period for physicians, a 7-year period for nurses, and a 9-year period for fetal doses. Patient-related dose metrics over an 8-year period were also analyzed.Results: In the physician and nursing groups, there was a nearly 70% decrease in the average occupational radiation doses over the given periods. Within the electrophysiology department, the average fetal occupational doses were very low, close to 0 μSv. The average reference point air kerma per patient for all electrophysiology procedures decreased from nearly 600 mGy/procedure in 2010 to just over 100 mGy/procedure in 2017.Conclusions: Patient and occupational radiation doses in our laboratories significantly decreased over the periods analyzed as a result of clinical and technical staff efforts as well as advances in imaging technology. The radiation-related risk to individuals working in our electrophysiology laboratories, including pregnant women, is very low. Data reported herein could be used by other institutions to evaluate their occupational and patient radiation safety practices. [ABSTRACT FROM AUTHOR]

Oxygenated target waters of cyclotron targets contain long-lived contaminants due to (p,n) reactions in the HAVAR target window that are spalled into the target water. These contaminants are largely removed during the synthesis of the final imaging agent. Currently the USP requires that the final drug product be 99.5% pure, so the total activity of the long-lived contaminants can be no more than 0.5% of the final radiopharmaceutical product. A method has been developed to identify and quantify the primary contaminants using high resolution gamma spectroscopy and VRF, a new spectrum analysis tool. Uptake, retention, and excretion functions for each of the contaminating isotopes in a soluble, injected chemical form have also been calculated using International Commission on Radiological Protection (ICRP) Publication 123 models and are presented in the Appendices A and B of Electronic Supplementary Material. In addition, specific organ and effective dose coefficients were also calculated using ICRP Publication 103 tissue weighting factors and are also presented in the Appendices A and B of Electronic Supplementary Material. Typical imaging agents have contaminant loads far below the USP limit and contribute negligible doses to the patients receiving the drugs. [ABSTRACT FROM AUTHOR]

Objectives: To analyse CT use in recent years in a high-density Italian area (±10 million inhabitants, including 1 million children), focusing on developing age.Methods: Retrospective analysis of records from HealthCare IT System, covering >400 hospitals and clinics. Description of CT use between 2004-2014 in emergency and outpatient care and assessment of radiation exposure trend.Results: Over 9 million scans were performed. Emergency procedures showed a global increase of 230 %, mainly head examinations. In the global outpatient setting, the annual number of CT scans/person increased ±19 %. A moderate increase in CT examinations was observed in the developing age population, while a remarkable increase in dental, chest and abdominal procedures occurred for the 10- to 30-year age range. The increase in mean annual dose/capita in the global patient pool was approximately 42 %, increasing from 0.72-1.03 mSv. The population rate receiving an annual CT radiation dose/capita higher than 1 mSv tripled in the 11-year interval, increasing from 16-48 %.Conclusions: The remarkable increase in radiation exposure raises a special concern for teenagers and young adults, whose risk tends to be underestimated. The fivefold increase in dental CTs in the younger age groups requires further investigations.Key Points: • Literature highlights a remarkable increase in CT use over the last decades. • The paediatric age had higher exposure to X-ray risk. • A detailed retrospective analysis of more than 9 million scans was performed. • Dental, chest, abdominal procedures increased remarkably in 10- to 30-year age range. • This study raises concern about exposure for teenagers and young adults. [ABSTRACT FROM AUTHOR]

Background: In a neonatal intensive care unit (NICU), preterm infants are often exposed to a large number of radiographic examinations, which could cause adjacent neonates, family caregivers and staff members to be exposed to a dose amount due to scatter radiation.Objective: To provide information on scatter radiation exposure levels in a NICU, to compare these values with the effective dose limits established by the European Union and to evaluate the effectiveness of radiation protection devices in this setting.Materials and Methods: Radiation exposure levels due to scatter radiation were estimated by passive detectors (thermoluminescent dosimeters) and direct dosimetric measurements (with a dose rate meter); in the latter case, an angular map of the scatter dose distribution was achieved.Results: The dose due to scatter radiation to staff in our setting is approximately 160 μSv/year, which is markedly lower than the effective dose limit for workers established by the European Union (20 mSv/year). The doses range between 0.012 and 0.095 μSv/radiograph. Considering a mean hospitalization period of 3 months and our NICU workload, the corresponding scatter radiation dose to an adjacent patient and/or his/her caregiver is at most 40 μSv.Conclusion: For distances greater than 1 m from the irradiation field, both scatter dose absorbed by a staff member during a year and that by an adjacent patient and/or his/her caregiver during hospitalization is less than 1 mSv, which is the exposure limit for public members in a year. [ABSTRACT FROM AUTHOR]

Objectives: A Working Group coordinated by the Italian National Institute of Health (Istituto Superiore di Sanità) and the National Workers Compensation Authority (Istituto Nazionale per l’Assicurazione contro gli Infortuni sul Lavoro, INAIL) and consisting of 11 Italian scientific/professional societies involved in the fluoroscopically guided interventional practices has been established to define recommendations for the optimization of patients and staff radiation protection in interventional radiology. A summary of these recommendations is here reported.Materials and methods: A multidisciplinary approach was used to establish the Working Group by involving radiologists, interventional radiologists, neuroradiologists, interventional cardiologists, occupational health specialists, medical physicists, radiation protection experts, radiographers and nurses. The Group operated as a “Consensus Conference”. Three main topics have been addressed: patient radiation protection (summarized in ten “golden rules”); staff radiation protection (summarized in ten “golden rules”); and education/training of interventional radiology professionals.Results: In the “golden rules”, practical and operational recommendations were provided to help the professionals in optimizing dose delivered to patients and reducing their own exposure. Operative indications dealt also with continuing education and training, and recommendations on professional accreditation and certification.Conclusions: The “Consensus Conference” was the methodology adopted for the development of these recommendations. Involvement of all professionals is a winning approach to improve practical implementation of the recommendations, thus getting a real impact on the optimization of the interventional radiology practices. [ABSTRACT FROM AUTHOR]

The use of digital radiographic systems has decreased the frequency of image retakes due to over/underexposure in general radiography. However, image retakes owing to patient positioning errors are likely to increase because of the convenience of a real-time image check on a console table. The purpose of the present study is to propose a novel radiographic examination procedure with an ultra-low-dose pre-test exposure that may be utilized to check patient positioning prior to taking an actual image, thereby reducing unnecessary patient exposure owing to image retakes. In this study, examination data from 714 knee joint radiographs, both submitted and retaken images, were included. Twelve radiological technologists (RTs) took all images. The actual total exposure dose for each patient was compared with simulated total doses utilized in the proposed procedure. The simulation assumed that each examination was completed following pre-test exposure. Therefore, this method did not involve retaking images although at least one pre-test exposure had been applied to all patients. Pre-test exposures at four dose levels corresponding to 25, 10, 5, and 2% of the actual exposure dose were evaluated to determine whether each dose level could be used to check patient positioning. The results indicated that when the pre-test exposure dose rate was 10% or lower, the total exposure dose reduction equaled or exceeded 8% for all patients. The use of the proposed procedure reduced the total exposure dose for all patients when compared to the exposure dose calculated from records. [ABSTRACT FROM AUTHOR]

Objectives: A national retrospective survey on patient doses was performed by the French Society of Medical physicists to assess reference levels (RLs) in interventional radiology as required by the European Directive 2013/59/Euratom.Methods: Fifteen interventional procedures in neuroradiology, vascular radiology and osteoarticular procedures were analysed. Kerma area product (KAP), fluoroscopy time (FT), reference air kerma and number of images were recorded for 10 to 30 patients per procedure. RLs were calculated as the 3rd quartiles of the distributions.Results: Results on 4600 procedures from 36 departments confirmed the large variability in patient dose for the same procedure. RLs were proposed for the four dosimetric estimators and the 15 procedures. RLs in terms of KAP and FT were 90 Gm.cm2 and 11 mins for cerebral angiography, 35 Gy.cm2 and 16 mins for biliary drainage, 75 Gy.cm2 and 6 mins for lower limbs arteriography and 70 Gy.cm2 and 11 mins for vertebroplasty. For these four procedures, RLs were defined according to the complexity of the procedure. For all the procedures, the results were lower than most of those already published.Conclusions: This study reports RLs in interventional radiology based on a national survey. Continual evolution of practices and technologies requires regular updates of RLs.Key Points: • Delivered dose in interventional radiology depends on procedure, practice and patient. • National RLs are proposed for 15 interventional procedures. • Reference levels (RLs) are useful to benchmark practices and optimize protocols. • RLs are proposed for kerma area product, air kerma, fluoroscopy time and number of images. • RLs should be adapted to the procedure complexity and updated regularly. [ABSTRACT FROM AUTHOR]

The use of parameters water equivalent diameter ( D ) and size-specific dose estimate (SSDE) are becoming increasingly established as a recognised method to relate patient dose from a CT examination to the dose indicator volume CT dose index (CTDI). However, the role of the attenuation due to the patient table in these estimations requires careful consideration and is the subject of this study. The aim of this study is to investigate the impact of a minimal part of the patient table when calculating the D and SSDE. We investigated 164 patients who had undergone CT examinations for the pelvis, abdomen, thorax and head. We subsequently calculated D and SSDE using two methods: one using a small circular region of interest (ROI) including a minimal part of the patient table and the other using a ROI fitted to the patient border alone. The results showed that the water equivalent diameter calculated with the table included in the ROI ( D ) is greater, compared to that without the consideration of the patient table ( D ), by 1.5-6.2% depending on the anatomy being imaged. On the other hand, the SSDE calculated with inclusion of the patient table (SSDE) is smaller than otherwise (SSDE) by 1.0-5.5% again depending on the anatomy being imaged. The effect of the patient table on D and SSDE in the thorax CT examination was statistically significant, but its effect on D and SSDE in the other examinations of head, pelvis and abdomen was relatively small and not statistically significant. [ABSTRACT FROM AUTHOR]

Purpose: Knowledge of medical radiation exposure permits application of radiation protection principles. In our center, the first dedicated real-time, automated patient and staff dose monitoring system (DoseWise Portal, Philips Healthcare) was installed. Aim of this study was to obtain insight in the procedural and occupational doses.Materials and Methods: All interventional radiologists, vascular surgeons, and technicians wore personal dose meters (PDMs, DoseAware, Philips Healthcare). The dose monitoring system simultaneously registered for each procedure dose-related data as the dose area product (DAP) and effective staff dose (E) from PDMs. Use and type of shielding were recorded separately. All procedures were analyzed according to procedure type; these included among others cerebral interventions (n = 112), iliac and/or caval venous recanalization procedures (n = 68), endovascular aortic repair procedures (n = 63), biliary duct interventions (n = 58), and percutaneous gastrostomy procedure (n = 28).Results: Median (±IQR) DAP doses ranged from 2.0 (0.8-3.1) (percutaneous gastrostomy) to 84 (53-147) Gy cm2 (aortic repair procedures). Median (±IQR) first operator doses ranged from 1.6 (1.1-5.0) μSv to 33.4 (12.1-125.0) for these procedures, respectively. The relative exposure, determined as first operator dose normalized to procedural DAP, ranged from 1.9 in biliary interventions to 0.1 μSv/Gy cm2 in cerebral interventions, indicating large variation in staff dose per unit DAP among the procedure types.Conclusion: Real-time dose monitoring was able to identify the types of interventions with either an absolute or relatively high staff dose, and may allow for specific optimization of radiation protection. [ABSTRACT FROM AUTHOR]

Videofluoroscopic swallowing study (VFSS) is considered the standard diagnostic imaging technique to investigate swallowing disorders and dysphagia. Few studies have been reported concerning the dose of radiation a patient receives and the scattering radiation dose received by a physician during VFSS. In this study, we investigated the dose of radiation (entrance skin dose, ESD) estimated to be received by a patient during VFSS using a human phantom (via a skin-dose monitor sensor placed on the neck of the human phantom). We also investigated the effective dose (ED) and dose equivalent (DE) received by a physician (wearing two personal dosimeters) during an actual patient procedure. One dosimeter (whole body) was worn under a lead apron at the chest, and the other (specially placed to measure doses received by the lens of the eye) outside the lead apron on the neck collar to monitor radiation doses in parts of the body not protected by the lead apron. The ESD for the patient was 7.8 mGy in 5 min. We estimated the average patient dose at 12.79 mGy per VFSS procedure. The physician ED and DE during VFSS were 0.9 mSv/year and 2.3 mSv/year, respectively. The dose of radiation received by the physician in this study was lower than regulatory dose limits. However, in accordance with the principle that radiation exposure should be as low as reasonably achievable, every effort should be made (e.g., wearing lead glasses) to reduce exposure doses. [ABSTRACT FROM AUTHOR]

Objective: To evaluate and compare novel robotic guidance and manual approaches based on procedural accuracy, procedural time, procedural performance, image quality as well as patient dose during image-guided microwave thermoablation. Method: The study was prospectively performed between June 2013 and December 2013 using 70 patients. Forty randomly selected patients (group 1) were treated with manual guidance and 30 patients (group 2) were treated using a novel robotic guidance. Parameters evaluated were procedural accuracy, total procedural time, procedural performance, quantitative/qualitative image quality and patient dose. Two-sided Student's t test and Wilcoxon rank-sum test were used to test the significance of the data and p values less than 0.05 were considered statistically significant. Result: Accuracy parameters were significantly higher in group 2 (all p < 0.05). Total procedural time showed a mean time difference of 3 min (group 2 > group 1; p = 0.0008). Volume CT dose index and dose-length product were significantly lower for group 2 compared to group 1 (all p < 0.05) for CT fluoroscopy imaging. Total procedural performance score was higher for group 2 compared to group 1 ( p = 0.0001). Image quality parameters were insignificant between examined groups. Conclusion: The novel robotic guided approach improved the accuracy of targeting the target tumour, reduced patient dose and increased procedural performance (which influences the procedural safety) during ablation. Key Points: • Few reports are available in the literature regarding robotic- assisted liver microwave ablation. • The robotic guided approach improved accuracy of localizing the target tumour. • Radiation dose on patients was reduced with the robotic guidance. • Numbers of insertions and readjustments were reduced, lowering chances of complications. [ABSTRACT FROM AUTHOR]

Our purpose in this study was to evaluate the potential of dose reduction in general radiography for adult patients by use of a dual-side-reading (DSR) photostimulable phosphor plate in a computed radiography system. The image quality and low-contrast detectability in terms of the contrast-detail diagram of the DSR system with use of the X-ray beam quality of the RQA 5 defined by the International Electrotechnical Commission 61267 were compared with those of a conventional single-side-reading (SSR) system. The radiographic noise of the DSR system was lower compared to that of the SSR system under the same exposure conditions. Although there were no statistical differences in low-contrast detectabilities between the SSR system and the DSR system under the same exposure levels, the DSR system showed superior detectability compared to the SSR system. We conclude that the DSR system for general radiography has the potential to reduce the patient dose. [ABSTRACT FROM AUTHOR]

Since its introduction in 1970s, Computed Tomography (CT) has evolved enormously to achieve fast temporal resolution, improved spatial resolution, better noise performance, and high image quality. While the conventional cone beam CT system provides 16 cm volumetric coverage in a single gantry rotation, large cone angles due to the increased detector size degrade image quality caused by insufficient data sampling. To overcome this, Inverse Geometry CT (IGCT) system was proposed. Instead of using a single focal spot and a large 2D detector array, the IGCT system uses a small 2D detector array and a multiple x-ray source array. Because of its inverted system geometry, the IGCT system can provide several benefits such as reduced scatter, isotropic resolution, improved temporal resolution, and reduced cone beam artifacts. A variant of IGCT system was proposed and in this paper we review three design schemes of the IGCT system; scanned source based IGCT, multiple source based IGCT, and stationary source based IGCT. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the radiation dose in routine multidetector computed tomography (MDCT) examinations in Italian population. Methods: This was a retrospective multicentre study included 5,668 patients from 65 radiology departments who had undergone common CT protocols: head, chest, abdomen, chest-abdomen-pelvis (CAP), spine and cardiac. Data included patient characteristics, CT parameters, volumetric CT dose index (CTDI) and dose length product (DLP) for each CT acquisition phase. Descriptive statistics were calculated, and a multi-regression analysis was used to outline the main factors affecting exposure. Results: The 75th percentiles of CTDI (mGy) and DLP (mGy cm) for whole head were 69 mGy and 1,312 mGy cm, respectively; for chest, 15 mGy and 569 mGy cm; spine, 42 mGy and 888 mGy cm; cardiac, 7 mGy and 131 mGy cm for calcium score, and 61 mGy and 1,208 mGy cm for angiographic CT studies. High variability was present in the DLP of abdomen and CAP protocols, where multiphase examinations dominated (71 % and 73 % respectively): for abdomen, 18 mGy, with 555 and 920 mGy cm in abdomen and abdomen-pelvis acquisitions respectively; for CAP, 17 mGy, with 508, 850 and 1,200 mGy cm in abdomen, abdomen-pelvis and CAP acquisitions respectively. Conclusion: The results of this survey could help in the definition of updated diagnostic reference levels (DRL). Key Points: • Radiation dose associated with multidetector CT (MDCT) is an important health issue. • This national survey assessed dose exposures of 5,668 patients undergoing MDCT. • Dose indices correlate with BMI, voltage, rotation time, pitch and tube current. • These results may contribute to an update of national diagnostic reference levels. [ABSTRACT FROM AUTHOR]

Our aim in this study was to investigate the incident air kerma (IAK) and average glandular dose (AGD) for polymethylmethacrylate (PMMA) phantoms and patient breasts for each thickness by use of digital mammography units, and to determine the correlation between phantom and patient measurements. An additional aim was to calculate the numerical value of the diagnostic reference level (DRL) for digital mammography in Japan based on the AGD from patient measurements. Patient-based IAK and AGD values were calculated for 300 patients who underwent mammographic examinations at three institutions. On examination of a 40-mm PMMA phantom, the IAK and the AGD were 7.89 and 1.84 mGy, respectively. The mean patient breast thickness was 37.6 mm, and the mean IAK and the AGD calculated from actual patient data for breast thicknesses between 40 mm and 50 mm were 8.91 and 2.08 mGy, respectively. Approximately 20 % of the 300 patients had IAK >10 mGy. The distributions of patient-based IAK and AGD values were higher than the IAK and AGD values for the PMMA phantom. The patient dose with use of the PMMA phantom can be underestimated. The DRL was calculated from patient-based AGDs of the regular breast thickness as 2.0 mGy in Japan. [ABSTRACT FROM AUTHOR]

Technetium-99m and iodine-131 are the leading isotopes used in diagnosis and radiotherapy, respectively in Pakistani nuclear medical centers. Both radionuclides are regularly supplied by Isotope Production Division (IPD), PINSTECH to nuclear medical centers in Pakistan. The packages of P, Mo → Tc generators, and I, are prepared at IPD and dispatched by air, rail or road according to the desired activity at reference day to nuclear medical centers. An accurate determination of the activity to be administered to the patient plays key role on the quality of the clinical result of a medical investigation. Activity meters are employed for quantification of radioactivity of radionuclides at supplier site as well as by the users. In order to investigate the performance on the quality of activity measurements and elution efficiency of PAKGEN Tc generators, a pilot program of intercomparison was organized between the supplier and the users. The results of intercomparison of the activity measurements showed a maximum difference of ±13 % between supplier and nuclear medical centers. [ABSTRACT FROM AUTHOR]

Objectives: A national study on patient dose values in interventional radiology and cardiology was performed in order to assess current practice in Bulgaria, to estimate the typical patient doses and to propose reference levels for the most common procedures. Methods: Fifteen units and more than 1,000 cases were included. Average values of the measured parameters for three procedures-coronary angiography (CA), combined procedure (CA + PCI) and lower limb arteriography (LLA)-were compared with data published in the literature. Results: Substantial variations were observed in equipment and procedure protocols used. This resulted in variations in patient dose: air-kerma area product ranges were 4-339, 6-1,003 and 0.2-288 Gy cm for CA, CA + PCI and LLA respectively. Reference levels for air kerma-area product were proposed: 40 Gy cm for CA, 140 Gy cm for CA + PCI and 45 Gy cm for LLA. Auxiliary reference intervals were proposed for other dose-related parameters: fluoroscopy time, number of images and entrance surface air kerma rate in fluoroscopy and cine mode. Conclusions: There is an apparent necessity for improvement in the classification of peripheral procedures and for standardisation of the protocols applied. It is important that patient doses are routinely recorded and compared with reference levels. Key Points: • Patient doses in interventional radiology are high and vary greatly • Better standardisation of procedures and techniques is needed to improve practice • Dose reference levels for most common procedures are proposed [ABSTRACT FROM AUTHOR]

Optimization and standardization of radiographic procedures in a health region minimizes patient exposure while producing diagnostic images. This report highlights the dose variation in common computed radiography (CR) examinations throughout a large health region. The RadChex cassette was used to measure the radiation exposure at the table or wall bucky in 20 CR rooms, in seven hospitals, using CR technology from two vendors. Exposures were made to simulate patient exposure (21 cm polymethyl methacrylate) under standard conditions for each bucky: 81 kVp at 100 cm for anteroposterior abdomen table bucky exposures (180 cm for posteroanterior chest wall bucky exposures), using the left, the right, or the center automatic exposure control (AEC) cells. Protocol settings were recorded. An average of 37% variation was found between AEC chambers, with a range between 4% and 137%. A 60% difference in dose was discovered between manufacturers, which was the result of the manufacture's image processing algorithm and subsequently corrected via software updates. Finally, standardizing AEC cell selection during common chest examinations could reduce patient dose by up to 30%. In a large health region, variation in exam protocols can occur, leading to unnecessary patient dose from the same type of examination. Quality control programs must monitor exam protocols and AEC chamber calibration in CR to ensure consistent, minimal, patient dose, regardless of hospital or CR vendor. Furthermore, this report highlights the need for communication between radiologists, technologists, medical physicist, service engineers, and manufacturers required to optimize CR protocols. [ABSTRACT FROM AUTHOR]

Manual exposure settings for radiographic projections were once based on a points system which assumed that the HVL in soft tissue is 3.0 cm and that each change of 1.0 cm of soft tissue corresponded to a change of 25% in image receptor dose. A set of mAs steps and equivalent kVp steps was estimated that would give appropriate technique factors for changes in patient thickness. With the advent of rare-earth screen-film systems and AEC systems the points system fell into disuse. Screen-film imaging systems have almost entirely been replaced by CR or DR systems and recently, standardised exposure indices have been recommended by the AAPM and IEC to provide exposure guidance for these systems. If the fundamental assumptions on which the points system was based are still valid for modern high-frequency generators and digital imaging systems, then there would be an elegant correspondence between the predictions of the points system and the requirements for correction of exposure errors indicated by the AAPM and IEC indices. This study estimated the HVL and attenuation per cm in soft tissue using computer simulation, finding that practically, the HVL is between 2.0 and 5.0 cm and attenuation per cm ranges from 15 to 25%. The study concluded that agreement between the points system predictions and the true effects of technique factors changes on dose to the image receptor was moderately good, that use of the points system and technique charts based on this system should be encouraged and that use of the IEC or AAPM digital exposure indices should be standardised. [ABSTRACT FROM AUTHOR]

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Copyright of La Radiologia Medica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A videofluoroscopy swallowing study (VFSS) is a major tool in diagnosing swallowing disorders. Like all other medical examinations that involve irradiation, patient dosage is a major concern. Cerebrovascular accident (CVA) and nasopharyngeal carcinoma (NPC) have been two of the most common indicating pathologies for VFSS studies. The goals of this study were to determine the mean dose area product (DAP) value and fluoroscopic time for VFSS examinations in Tuen Mun Hospital, to compare the result with the dose reference level of other similar studies, and to document the results with respect to the various common indicating pathologies for VFSS (i.e., CVA, NPC). Three hundred ninety-eight VFSS exams were performed at our center in a 24-month period; the mean DAP was 2.42 ± 2.04 Gy cm2 for an effective dose of 0.31 ± 0.26 mSv. The mean fluoroscopic time is 4.23 ± 2.56 min. The P value of 0.0034 was obtained using the Kruskal–Wallis test to compare the DAP from various groups of indicating pathologies. It suggests that there are significant differences in dosage between CVA and NPC patients and the entire population. We conclude that the dose of radiation received by a patient undergoing a VFSS examination in our center was comparable to the international standard and that of other similar studies. We can also conclude that there is a significant difference in dosage between NPC and CVA patients and the overall population suggesting that the indicating pathologies for a VFSS have certain effects on the resulting irradiating dose delivered but more studies have to be done to explain such differences. [ABSTRACT FROM AUTHOR]

Copyright of La Radiologia Medica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of La Radiologia Medica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is known that interventional neuroradiology (IN) involves high radiation dose to both patients and staff even if performed by trained operators using modern fluoroscopic X-ray equipment and dose-reducing technology. Therefore, every new technology or imaging tool introduced, such as three-dimensional rotational angiography (3D RA), should be evaluated in terms of radiation dose. 3D RA requires a series with a large number of images in comparison with 2D angiography and it is sometimes considered a high-dose IN procedure. The literature is scarce on the 3D RA radiation dose and in particular there are no data on carotid arteriography (CA). The aim of this study was to investigate patient dose differences between 2D and 3D CA. The study included 35 patients undergoing 2D CA in hospital 1 and 25 patients undergoing 3D CA in hospital 2. Patient technical data collection included information on the kerma area product (KAP), fluoroscopy time (T), total number of series (S), and total number of acquired images (F). Median KAP was 112 Gy cm2 and 41 Gy cm2 for hospitals 1 and 2, respectively, median T was 8.2 min and 5.1 min, median S was 13 and 4, and median F was 247 and 242. Entrance surface air-kerma rate, as measured in “medium” fluoroscopy mode measured in 2D acquisition using a 20 cm phantom of polymethylmethacrylate, was 17.3 mGy/min for hospital 1 and 9.2 mGy/min for hospital 2. 3D CA allows a substantial reduction in patient radiation dose compared with 2D CA, while providing the necessary diagnostic information. [ABSTRACT FROM AUTHOR]

A nationwide survey was launched to investigate the use of fluoroscopy and establish national reference levels (RL) for dose-intensive procedures. The 2-year investigation covered five radiology and nine cardiology departments in public hospitals and private clinics, and focused on 12 examination types: 6 diagnostic and 6 interventional. A total of 1,000 examinations was registered. Information including the fluoroscopy time (T), the number of frames (N) and the dose-area product (DAP) was provided. The data set was used to establish the distributions of T, N and the DAP and the associated RL values. The examinations were pooled to improve the statistics. A wide variation in dose and image quality in fixed geometry was observed. As an example, the skin dose rate for abdominal examinations varied in the range of 10 to 45 mGy/min for comparable image quality. A wide variability was found for several types of examinations, mainly complex ones. DAP RLs of 210, 125, 80, 240, 440 and 110 Gy cm2 were established for lower limb and iliac angiography, cerebral angiography, coronary angiography, biliary drainage and stenting, cerebral embolization and PTCA, respectively. The RL values established are compared to the data published in the literature. [ABSTRACT FROM AUTHOR]

Objectives. This study investigated the effect of the size of the sensitive area of the charge-coupled devices (CCD) used in digital intraoral radiographic systems on the patient effective dose in full-mouth radiographic examinations. Methods. The effective dose was assessed in full-mouth radiographic examinations using the bisecting angle technique, while assuming that CCD sensitivity is equivalent to that of E-speed film. The results were compared with the effective doses obtained using E-speed film. The tube potentials used were 70, 80, and 90kV. The diameter of the circular field at the cone tip was 7 cm, and the length of the spacer cone was 20 cm. Twelve types of CCD devices with sensitive areas ranging from 307 to 1200mm² were assessed in seven digital intraoral radiographic systems. Results. The number of exposures and effective dose using the CCD devices were inversely proportional to the sensitive area of the CCD. Both the number of exposures and the effective dose were increased when using a CCD with a sensitive area smaller than the intraoral film size. Consequently, a reduction in the patient dose did not occur to the extent expected, based on the relative sensitivity of the CCD to film. Conclusions. In order to fully realize the advantages of a CCD, it will be necessary both to reduce the frequency of examinations and to use a rectangular-shaped beam in CCD-based intraoral radiographic systems. [ABSTRACT FROM AUTHOR]

The surface doses to patients during chest, abdomen and pelvis radiography were measured over a period of 3 years, during which time computed radiography (CR) and digital radiography (DR) systems were introduced to replace film–screen systems. For film–screen and CR the surface doses were measured with thermoluminescent dosimeters. For DR the surface doses were calculated from the dose–area product (DAP) meter readings. Measurements were made for each type of examination and detector type on 10 average-size patients. Measurements were made immediately after the new systems were introduced, and subsequently as adjustments were made to optimize dose and image quality. Published diagnostic reference levels were used as target values in this optimization. Initially, CR doses were the same as or higher than for film–screen, and the doses were lower for DR compared to film–screen. Subsequent clinical experience with the systems led to changes in the technique used for chest examinations both for CR and for DR. For CR, it was possible to change the algorithm and decrease the dose to one quarter of the initial value with acceptable image quality. For DR, it was decided to reduce noise by increasing the dose by a factor of two. No changes were made to abdomen or pelvic imaging techniques for either CR or DR. The final patient surface doses using CR were similar to published diagnostic reference doses; for DR, all patient doses were less than published reference levels. [ABSTRACT FROM AUTHOR]

A study was conducted to investigate the effect of increasing x-ray tube voltage on patient dose and image quality during computed radiography (CR) examination of the lumbar spine. Images of a pelvis — lumbar spine phantom were obtained at three different tube voltages using two CR systems. The images were evaluated by image scores (IS) using the image quality criteria proposed by the Commission of the European Communities (CEC), by measuring the signal-to-noise ratio and the contrast-to-noise ratio. The entrance surface dose (ESD) to the phantom was also measured using ionisation chambers and the resulting gonad dose (G) and effective dose (E) were calculated. The CEC recommended tube voltages can be exceeded with CR systems for lumbar spine radiography. The ESD, G and E decreased by 25% –50% with both CR systems when tube voltage was increased. Although the decrease in IS was statistically significant ( P<0.05) the images obtained with the 3 tube voltages were diagnostically acceptable. The balance between image quality and patient dose can be optimised by using higher x-ray tube voltages for lumbar spine CR examinations. [ABSTRACT FROM AUTHOR]

In performing experimental or theoretical studies of the effect of source to image distance on dose to the patient, it is conventional to assume that the dose to the image receptor should remain constant at each SID. However, if the proportion of scattered radiation reaching the image receptor depends on the SID, then this assumption will be invalid. In this paper, the effect of SID on the scatter fraction has been determined using a Monte Carlo simulation, using EGSnrcMP. The Monte Carlo code was first benchmarked against three independent experimental studies, and shown to give excellent agreement. In order to obtain agreement with experiment, it was necessary to include Rayleigh scatter and bound Compton effects and to properly simulate multiple scattering. The scatter fraction was then determined for a range of SIDs from 100 to 300 cm, for a range of conditions, including kVp setting, phantom thickness, field size, object to image distance, collimation to entrance surface, centre of phantom and image receptor, and a range of image receptor materials. The results indicate that the scatter fraction is independent of SID within a few percent, except when there is a large object to image distance. [ABSTRACT FROM AUTHOR]

This article reviews developments in Europe over the past 10 years in the radiation protection of patients undergoing medical X-ray examinations that led to the requirement in the EC Medical Exposure Directive of 1997 that all Member States should establish Diagnostic Reference Levels (DRLs). The purpose of DRLs is explained and methods for deriving national DRLs that comply with the requirements of the Directive are described. Suitable patient dose quantities are defined and dose measurement methods and patient sampling techniques that can be used both by the appropriate authorities for setting national DRLs, and by individual X-ray departments for checking compliance with them, are discussed. Finally, the progress made over the past 5 years in translating the requirements of the Directive into national legislation, including the provision of guidance on the use of DRLs for X-ray departments, is reviewed. It relies heavily on the author’s experience of how these matters are progressing in the UK, but will hopefully be of some practical help to the staff in X-ray departments from all over Europe. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare performance and patient dose of full-field digital mammography units for clinical use. Measurements of linearity and automatic exposure control stability were performed on four units installed in as many Italian sites. The tube output was also obtained by the same ionization chamber, permitting to evaluate ratios mGy/mAs for each available spectrum. The entrance air-kerma was calculated over a sample of 800 cranio-caudal mammograms and the average glandular dose obtained, assuming two mean glandular compositions of 50 and 30%, respectively. Digital systems showed very good linearity and comparable responses. The stability of the automatic exposure control was better than 5% for all systems. Regarding doses, the two mammography units that work mainly in contrast mode deliver, respectively, 17 and 28% more dose compared with those working in standard mode. For the latter mode, the mean average glandular dose was in the range 1.25-1.37 mGy and 1.37-1.49 mGy for the 50 and 30% glandular composition, respectively. Results of this study were compared with those of other surveys, showing that full-field digital mammography allows a significant clinical dose reduction compared with screen/film mammography. [ABSTRACT FROM AUTHOR]

Diagnostic nuclear medicine procedures in a large hospital in northern Greece during 1984-1988 have been surveyed in order to estimate the radiation burden to the patients. The mean effective dose equivalent (EDE) was found to be 1.96 mSv/examination and 2.46 mSv/patient, allowing for the fact that a number of patients underwent more than one examination. Apart from EDE, absorbed dose has been calculated for bone marrow, thyroid, gonads, kidneys and bladder. Patients undergoing multiple examinations have been used to calculate true 'patient dose distribution' as well as 'patient time-weighted dose distribution'. Because of the predominance of renal examinations, 8.5 fatal renal malignancies are expected per 100000 patients. [ABSTRACT FROM AUTHOR]