Reduce Patient Radiation Dose Research Articles

Optimisation of cone beam CT radiotherapy imaging protocols using a novel 3D printed head and neck anthropomorphic phantom

Objective.This study aimed to optimise Cone Beam Computed Tomography (CBCT) protocols for head and neck (H&N) radiotherapy treatments using a 3D printed anthropomorphic phantom. It focused on precise patient positioning in conventional treatment and adaptive radiotherapy (ART).Approach.Ten CBCT protocols were evaluated with the 3D-printed H&N anthropomorphic phantom, including one baseline protocol currently used at our centre and nine new protocols. Adjustments were made to milliamperage and exposure time to explore their impact on radiation dose and image quality. Additionally, the effect on image quality of varying the scatter correction parameter for each of the protocols was assessed. Each protocol was compared against a reference CT scan. Usability was assessed by three Clinical Scientists using a Likert scale, and statistical validation was performed on the findings.Main results. The work revealed variability in the effectiveness of protocols. Protocols optimised for lower radiation exposure maintained sufficient image quality for patient setup in a conventional radiotherapy pathway, suggesting the potential for reducing patient radiation dose by over 50% without compromising efficacy. Optimising ART protocols involves balancing accuracy across brain, bone, and soft tissue, as no single protocol or scatter correction parameter achieves optimal results for all simultaneously.Significance.This study underscores the importance of optimising CBCT protocols in H&N radiotherapy. Our findings highlight the potential to maintain the usability of CBCT for bony registration in patient setup while significantly reducing the radiation dose, emphasizing the significance of optimising imaging protocols for the task in hand (registering to soft tissue or bone) and aligning with the as low as reasonably achievable principle. More studies are needed to assess these protocols for ART, including CBCT dose measurements and CT comparisons. Furthermore, the novel 3D printed anthropomorphic phantom demonstrated to be a useful tool when optimising CBCT protocols.

Comparative study of image quality and radiation dose in thoracic-abdominal-pelvic CT Enhancement with different tube voltages and reconstruction algorithms

ObjectivesTo evaluate the image quality and radiation dose in thoracic-abdominal-pelvic computed tomography enhancement using ATVM (Automatic Tube Voltage Modulation)coupled with AIIR versus routine tube voltage combined with Karl-3D IR. The optimal noise level for the AIIR in thoracic-abdominal-pelvic CT enhancement was also determined. MethodsGroup A was scanned using ATVM, and images were reconstructed using AIIR with 1–5 noise levels. Group B was scanned and reconstructed using the fixed tube voltage (120 kVp) combined with Karl 3D level 5 IR. The image quality of the reconstructed images of AIIR with 1–5 noise levels were compared and the best image reconstruction noise level for AIIR was preferred. Image quality and radiation dose were statistically analyzed for group A (best image reconstruction noise level for AIIR) and group B. ResultsAIIR level 3 is the optimal noise level for CT-enhanced image reconstruction of the thorax, abdomen, and pelvis. The mean SNR, CNR, and subjective evaluation of AIIR level 3 Group A images were better than those of Karl 3D level 5 Group B images (p < 0.05). The mean SSDE and the mean ED of the AIIR Group A patients were reduced by 46% and 41%, respectively, compared with those of Group B. ConclusionsATVM technology combined with the AIIR algorithm improved image quality and reduced patient radiation dose in thoracic-abdominal-pelvic CT scans. The optimal noise level for the reconstruction of high-quality arterial and venous-phase images was AIIR level 3.

Analyzer-free hard x-ray interferometry

Objective. To enable practical interferometry-based phase contrast CT using standard incoherent x-ray sources, we propose an imaging system where the analyzer grating is replaced by a high-resolution detector. Since there is no need to perform multiple exposures (with the analyzer grating at different positions) at each scan angle, this scheme is compatible with continuous-rotation CT apparatus, and has the potential to reduce patient radiation dose and patient motion artifacts. Approach. Grating-based x-ray interferometry is a well-studied technique for imaging soft tissues and highly scattering objects embedded in such tissues. In addition to the traditional x-ray absorption-based image, this technique allows reconstruction of the object phase and small-angle scattering information. When using conventional incoherent, polychromatic, hard x-ray tubes as sources, three gratings are usually employed. To sufficiently resolve the pattern generated in these interferometers with contemporary x-ray detectors, an analyzer grating is used, and consequently multiple images need to be acquired for each view angle. This adds complexity to the imaging system, slows image acquisition and thus increases sensitivity to patient motion, and is not dose efficient. By simulating image formation based on wave propagation, and proposing a novel phase retrieval algorithm based on a virtual grating, we assess the potential of a analyzer-grating-free system to overcome these limitations. Main results. We demonstrate that the removal of the analyzer-grating can produce equal image contrast-to-noise ratio at reduced dose (by a factor of 5), without prolonging scan duration. Significance. By demonstrating that an analyzer-free CT system, in conjuction with an efficient phase retrieval algorithm, can overcome the prohibitive dose and workflow penalties associated grating-stepping, an alternative path towards realizing clinical inteferometric CT appears possible.

Synthetic CT generation from MRI using 3D transformer-based denoising diffusion model.

Magnetic resonance imaging (MRI)-based synthetic computed tomography (sCT) simplifies radiation therapy treatment planning by eliminating the need for CT simulation and error-prone image registration, ultimately reducing patient radiation dose and setup uncertainty. In this work, we propose a MRI-to-CT transformer-based improved denoising diffusion probabilistic model (MC-IDDPM) to translate MRI into high-quality sCT to facilitate radiation treatment planning. MC-IDDPM implements diffusion processes with a shifted-window transformer network to generate sCT from MRI. The proposed model consists of two processes: a forward process, which involves adding Gaussian noise to real CT scans to create noisy images, and a reverse process, in which a shifted-window transformer V-net (Swin-Vnet) denoises the noisy CT scans conditioned on the MRI from the same patient to produce noise-free CT scans. With an optimally trained Swin-Vnet, the reverse diffusion process was used to generate noise-free sCT scans matching MRI anatomy. We evaluated the proposed method by generating sCT from MRI on an institutional brain dataset and an institutional prostate dataset. Quantitative evaluations were conducted using several metrics, including Mean Absolute Error (MAE), Peak Signal-to-Noise Ratio (PSNR), Multi-scale Structure Similarity Index (SSIM), and Normalized Cross Correlation (NCC). Dosimetry analyses were also performed, including comparisons of mean dose and target dose coverages for 95% and 99%. MC-IDDPM generated brain sCTs with state-of-the-art quantitative results with MAE 48.825±21.491 HU, PSNR 26.491±2.814dB, SSIM 0.947±0.032, and NCC 0.976±0.019. For the prostate dataset: MAE 55.124±9.414 HU, PSNR 28.708±2.112dB, SSIM 0.878±0.040, and NCC 0.940±0.039. MC-IDDPM demonstrates a statistically significant improvement (with p<0.05) in most metrics when compared to competing networks, for both brain and prostate synthetic CT. Dosimetry analyses indicated that the target dose coverage differences by using CT and sCT were within±0.34%. We have developed and validated a novel approach for generating CT images from routine MRIs using a transformer-based improved DDPM. This model effectively captures the complex relationship between CT and MRI images, allowing for robust and high-quality synthetic CT images to be generated in a matter of minutes. This approach has the potential to greatly simplify the treatment planning process for radiation therapy by eliminating the need for additional CT scans, reducing the amount of time patients spend in treatment planning, and enhancing the accuracy of treatment delivery.

Deep-learned generation of renal dual-energy CT from a single-energy scan

To investigate the role of the deep-learning (DL) method in the generation of dual-energy computed tomography (DECT) images from single-energy images for precise diagnosis of kidney stone type. DECT of 23 patients was acquired, and the stone types were investigated based on the DECT software suggestions. The data were divided into two paired groups:120 kVp input and 80 kVp target and 120 kVp input and 135 kVp targets, p2p-UNet-GAN was exploited to generate the different energy images based on the common CT protocols. The images generated of the generative adversarial network (GAN) network were evaluated based on the SSIM, PSNR, and MSE metrics, and the values were estimated as 0.85-0.95, 28-32, and 0.85-0.89 respectively. The attenuation ratio of test patient images were estimated and compared with real patient reports. The network achieved high accuracy in stone region localisation and resulted in accurate stone type predictions. This study presents a useful method based on the DL technique to reduce patient radiation dose and facilitate the prediction of urinary stone types using single-energy CT imaging.

Multiphase photon counting detector CT data sets – Which combination of contrast phase and virtual non-contrast algorithm is best suited to replace true non-contrast series in the assessment of active bleeding?

PurposeAim of this study was to determine which virtual non-contrast (VNC) reconstruction algorithm, applied to which contrast phase of computed tomography angiography, best matches true non-contrast (TNC) images in the assessment of active bleeding. MethodPatients who underwent a triphasic scan (pre-contrast, arterial, portal venous contrast) on a photon-counting detector CT (PCD-CT) (120 kV, image quality level 68) with suspected active (tumor, postoperative, spontaneous or other) bleeding were retrospectively included in this study. Conventional (VNCConv) and a calcium-preserving VNC algorithm (VNCPC) were derived from both arterial (art) and portal venous (pv) contrast scans, and analyzed quantitatively and qualitatively by two independent and blinded raters. Results40 patients (22 female, mean age 76 years) were included. Measurements of CT values showed significant albeit small differences between TNC and VNC for most analyzed tissue regions without clear superiority of a VNC algorithm or contrast phase (e.g. ΔHU fat TNC to VNCPCpv 3.1 HU). However, qualitative analysis showed a preference to VNCPCpv in terms of image quality (on a 5-point Likert scale VNCConvart = 3.5 ± 0.8, VNCPCart = 3.7 ± 0.7, VNCConvpv = 3.7 ± 0.7, VNCPCpv = 3.8 ± 0.7) and residual calcium contrast (VNCConvart = 3.0 ± 0.8, VNCPCart = 3.5 ± 0.7, VNCConvpv = 3.6 ± 0.7, VNCPCpv = 3.9 ± 0.6). ConclusionsWhen multiple post-contrast phases are available, VNCPC series based on portal venous phase are the most suitable replacement for an additional pre-contrast scan, with the prospect of a significant reduction in patient radiation dose.

Diagnostic Validity Of Low Dose CT KUB In Demonstration Of Genitourinary Tract Calculi Compared To Normal Dose Ct Kub: A Provisional Study

Objective: Renal colic is a common clinical condition. Our objective is to evaluate the diagnostic accuracy of low dose CT KUB for detection of urinary stones, to minimize radiation dose to the patients, and to analyze diagnostic accuracy of LDCT KUB in comparison to standard dose CT KUB. We speculate the LDCT KUB may reduce patient radiation dose while maintaining diagnostic value.&#x0D; Materials and Methods: This comparative cross sectional validation study was conducted at Department of Radiology in Benazir Bhutto Hospital, Rawalpindi June 2021 to Feb 2022. After approval of hospital ethical committee, a sample of 49 kidneys of 31 patients was collected by non-probability consecutive sampling technique. Included were the patients diagnosed with renal calculi referred from other departments. All the included patients were scanned by Toshiba Aquilion 16 slices, using automated tube current modulation, without any oral or IV contrast. CT scan started from diaphragm down to pubic symphysis with standard dose CT (SDCT) followed by low dose CT (LDCT). After the data was recorded, statistical package for social sciences, version 20.0 (SPSS Inc., Chicago, Illinois, USA) was used to analyse the data and generate results. Mean + standard deviation was calculated for qualitative data while frequency and percentage for qualitative variables. The means were compared by independent sample t test while the agreement between standard and low dose was depicted by kappa value.&#x0D; Results: A total of 49 kidneys of 31 patients with renal stones was included in this study. The mean age of the patients ranged from 27 years to 48 years with a mean of 36.42 + 9.97 year. In gender distribution, 75.5 % (37) were male while 24.5 % (12) were females. More than half 59 % (29) were right while 41 % (20) were left kidneys.&#x0D; Conclusion: This study demonstrated that LDCT was a productive and effective technique in the detection of urothelial stones despite considerable reduction in radiation dose and exposure as seen in SDCT.

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.

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.

Use of a 2 Dimensional Vessel Navigator Roadmap Decreases Patient Radiation Dose Compared to Standard 3D Mapping for Fenestrated Endovascular Aneurysm Repair

For fenestrated endovascular aneurysm repair (FEVAR), the implementation of the VesselNavigator (Philips Healthcare, Best, The Netherlands) to provide a 3-dimensional vessel roadmap has been shown to reduce patient radiation exposure. Unfortunately, FEVAR radiation doses remain substantial despite utilization of this technology. Traditionally, registration of the live fluoroscopy with the pre-operative CTA is performed via the acquisition of a low-dose cone-beam CT scan. However, this registration can also be accomplished with the acquisition of 2D X-rays using the c-arm in 2 different projection angles. We hypothesized that the 2D image acquisition for vessel roadmap development would result in a significant reduction in patient radiation dose in comparison to the 3D CT registration without compromising image quality or increasing procedural length. This single-center, retrospective study included FEVARs performed from January 2015 to May 2019. For patient data, the cumulative reference air kerma (RAK) was presented as geometric mean and standard deviation. A general linear model with log-normal distribution was used to test the difference in patient RAK between 2D X-ray and 3D CT VesselNavigator registration after adjusting for BMI and the number of vessel fenestrations (1 to 2 vs. 3 to 4). Fluoroscopy time was recorded and used as a surrogate for case complexity. All analyses were done in SAS 9.4 (SAS Institute, Inc., Cary, North Carolina). One hundred and sixty four FEVARs were performed on a Philips Allura Xper FD 20 fluoroscopy system equipped with clarity technology. The VesselNavigator registration was completed using 3D CT mapping in 99 cases and 2D X-rays in 65 procedures. On average, utilization of 2D mapping versus 3D mapping for the VesselNavigator resulted in a 20.4% reduction in patient RAK after controlling for BMI and number of vessel fenestrations, P = 0.0135. There was no significant difference in fluoroscopy time between the 2 study groups (P= 0.81) suggesting that image quality was not compromised by the use of 2D mapping leading to the need for additional fluoroscopy. Acquisition of 2D films rather than a 3D CT scan for VesselNavigator registration allows for a significant reduction in patient radiation dose during FEVAR without increasing the case complexity or compromising image quality.

Eye protection in interventional procedures.

Data suggest that radiation-induced cataracts may form without a threshold and at low-radiation doses. Staff involved in interventional radiology and cardiology fluoroscopy-guided procedures have the potential to be exposed to radiation levels that may lead to eye lens injury and the occurrence of opacifications have been reported. Estimates of lens dose for various fluoroscopy procedures and predicted annual dosages have been provided in numerous publications. Available tools for eye lens radiation protection include accessory shields, drapes and glasses. While some tools are valuable, others provide limited protection to the eye. Reducing patient radiation dose will also reduce occupational exposure. Significant variability in reported dose measurements indicate dose levels are highly dependent on individual actions and exposure reduction is possible. Further follow-up studies of staff lens opacification are recommended along with eye lens dose measurements under current clinical practice conditions.

Technical evaluation of a prototype ratio 29:1 grid for adult patient cardiovascular angiography imaging conditions

The purpose of this work was to assess technical performance of a prototype high-ratio (r29), 80 line cm−1 grid for imaging conditions which mimic those for adult cardiovascular angiography. The standard equipment r15, 80 line cm−1 grid was used as a reference. Plastic Water® LR phantoms with thickness in the range 20–44 cm were used to simulate adult patient attenuation and scatter. Grids were tested using x-ray field of view 20 and 25 cm and x-ray source to detector distance (SID) 107 and 120 cm. The primary transmission fraction (TP ) was measured using both narrow beam geometry and a lead beam stop (BS) technique. Scatter transmission (TS ) was measured with the lead BS technique. The quantum signal to noise ratio improvement factor (K SNR) was used to describe relative grid performance. The experimental conditions required revised theory to assess grid performance. Theory to account for the detector glare and underestimation of scatter intensity by the lead BS method was developed. Also, novel K SNR theory was developed to allow direct comparison of two grids operated at different SID. Mean TP was modestly lower for the r29 versus r15 grid (0.69 versus 0.75). When tested under equivalent scatter condition, TS of the r29 grid was approximately ½ that of the r15 grid (0.18 versus 0.34). K SNR of the r29 grid at SID 120 cm compared to the r15 grid at SID 107 cm increased linearly with phantom thickness (range 1.0 to ∼1.16). Findings of this work indicate that the r29 grid used at SID 120 cm is expected to provide improved image quality (or reduced patient radiation dose) when compared to the r15 grid used at SID 107 cm for adult cardiovascular patients and that the potential benefit of the r29 grid increases with patient thickness >20 cm.

Artificial intelligence in medical imaging: implications for patient radiation safety.

Artificial intelligence, including deep learning, is currently revolutionising the field of medical imaging, with far reaching implications for almost every facet of diagnostic imaging, including patient radiation safety. This paper introduces basic concepts in deep learning and provides an overview of its recent history and its application in tomographic reconstruction as well as other applications in medical imaging to reduce patient radiation dose, as well as a brief description of previous tomographic reconstruction techniques. This review also describes the commonly used deep learning techniques as applied to tomographic reconstruction and draws parallels to current reconstruction techniques. Finally, this paper reviews some of the estimated dose reductions in CT and positron emission tomography in the recent literature enabled by deep learning, as well as some of the potential problems that may be encountered such as the obscuration of pathology, and highlights the need for additional clinical reader studies from the imaging community.

Patient Dose Assessment During Radiological Examination: Case of the Vakinankaratra and Haute Matsiatra Regions of Madagascar

The medical use of ionizing radiation is the largest and a growing man-made source of radiation exposure. The aim of this study is to assess the doses received by patients during radiological examinations in order to standardize the examination procedures and optimize the patient dose. Four most frequented hospitals, located in the Vakinankaratra and Haute Matsiatra regions of Madagascar, were investigated. Patients dose undergoing chest posterior-anterior (PA) and lateral (LAT), skull (PA, LAT), lumbar spine (PA, LAT), spine cervical (PA, LAT), abdomen (AP, LAT) and members (AP, PA, LAT) X-ray examinations were involved in this study. Entrance Skin Dose (ESD) was calculated using the X-ray radiation output and the exposure parameters (high voltage, tube loading, focus-patient distance). Thermoluminescent dosimeters were used to measure the X-rays radiation output. Conversion coefficients were used to relate ESD to the effective dose (ED). A total of 302 radiographic examinations were collected from the four hospitals during two months of 2019. The highest ESD (mGy) was found for the lumbar spine lateral projection, with an average value of 2.66 mGy. The highest value of ED was observed for the abdomen lateral projection with an average of 0.174 mSv. The ESDs and EDs reported in this study are generally lower than reference dose values published by the IAEA. This trend is an indication that the patient radiation protection practices in these four hospitals are already acceptable. The results of this study showed that there is a need to improve the radiodiagnostic procedures for reducing patient radiation dose without affecting the quality of the radiography image. The data of this work will be useful in contributing to the formulation of regional guidance levels.

High filtration in interventional practices reduces patient radiation doses but not always scatter radiation doses.

In fluoroscopy-guided interventional practices, new dose reduction systems have proved to be efficient in the reduction of patient doses. However, it is not clear whether this reduction in patient dose is proportionally transferred to operators' doses. This work investigates the secondary radiation fields produced by two kinds of interventional cardiology units from the same manufacturer with and without dose reduction systems.Methods:Data collected from a large sample of clinical procedures over a 2-year period (more than 5000 procedures and 340,000 radiation events) and the DICOM radiation dose structured reports were analysed. The average cumulative Hp(10) per procedure measured at the C-arm was similar for the standard and the dose reduction systems (452 vs 476 μSv respectively). The events analysis showed that the ratio Hp(10)/KAP at the C-arm was (mean ± SD) 5 ± 2, 10 ± 4, 14 ± 4 and 14 ± 6 μSv·Gy-1·cm-2 for the beams with no added filtration, 0.1, 0.4 and 0.9 mm Cu respectively and suggested that the main cause for the increment of the ratio Hp(10)/KAP vs the "standard system" is the use of higher beam filtration in the "dose reduction" system. Dose reduction systems are beneficial to reduce KAP in patients and their use should be encouraged, but they may not be equally effective to reduce occupational doses. Interventionalists should not overlook their own personal protection when using new technologies with dose reduction systems. Dose reduction technology in interventional systems may increase scatter dose for operators. Personal protection should not be overlooked with dose reduction systems.

TCT CONNECT-187 Characteristics Associated With Reduced Patient Radiation Dose in an Academic Cardiac Catheterization Lab

TCT CONNECT-187 Characteristics Associated With Reduced Patient Radiation Dose in an Academic Cardiac Catheterization Lab

The z-sbDBA, a new concept for a dynamic sheet-based fluence field modulator in x-ray CT.

We present a new concept for dynamic fluence field modulation (FFM) in x-ray computed tomography (CT). The so-called z-aligned sheet-based dynamic beam attenuator (z-sbDBA) is developed to dynamically compensate variations in patient attenuation across the fan beam and the projection angle. The goal is to enhance image quality and to reduce patient radiation dose. The z-sbDBA consists of an array of attenuation sheets aligned along the direction. In neutral position, the array is focused toward the focal spot. Tilting the z-sbDBA defocuses the sheets, thus reducing the transmission for larger fan beam angles. The structure of the z-sbDBA significantly differs from the previous sheet-based dynamic beam attenuator(sbDBA) in two features: (a) The sheets of the z-sbDBA are aligned parallel to the detector rows, and (b)the height of the sheets increases from the center toward larger fan beam angles. We built a motor actuated prototype of the z-sbDBA integrated into a clinical CT scanner. In experiments, we investigated its feasibility for FFM. We compared the z-sbDBA to common CT bowtie filters in terms of the spectral dependency of the transmission and possible image variance distribution in reconstructed phantom images. Additionally, the potential radiation dose saving using z-sbDBA for region-of-interest (ROI) imaging was studied. Our experimental results confirm that the z-sbDBA can realize variable transmission profiles of the radiation fluence by only small tilts. Compared to the sbDBA, the z-sbDBA can mitigate some practical and mechanical issues. In comparison to bowtie filters, the spectral dependency is considerably reduced when using the z-sbDBA. Likewise, more homogeneous image variance distributions can be attained in reconstructed phantom images. The z-sbDBA allows controlling the spatial image variance distribution which makes it suitable for ROI imaging. Our comparison on ROI imaging reveals skin dose reductions of up to 35% at equal ROI image quality by using the z-sbDBA. Our new concept for FFM in x-ray CT, the z-sbDBA, was experimentally validated on a clinical CT scanner. It facilitates dynamic FFM by realizing variable transmission profiles across the fan beam angle on a projection-wise basis. This key feature allows for substantial improvements in image quality, a reduction in patient radiation dose, and additionally provides a technical solution for ROI imaging.

Occupational and Patient Radiation Dose Reduction With a Reduced Frame Rate and Roentgen Protocol Using Fixed Imaging

Occupational and Patient Radiation Dose Reduction With a Reduced Frame Rate and Roentgen Protocol Using Fixed Imaging

Application of DynaCT angiographic reconstruction in balloon pulmonary angioplasty.

To investigate the feasibility and accuracy of balloon pulmonary angioplasty (BPA) using DynaCT angiographic reconstruction guidance. Thirty-four BPAs (23 CTEPH patients) targeting 175 pulmonary arteries were included. Eleven BPAs (2D group) were guided by DSA two-dimensional angiography. Another twenty-three BPAs (3D group) were guided using DynaCT angiographic reconstruction. The volume rendering (VR) method was used to obtain a three-dimensional image of the blood vessels. This image was used as a reference to continue BPA treatment under the guidance of vascular three-dimensional reconstruction technology. Procedure durations and radiation exposure data were compared between the two groups using Mann-Whitney U test. Using the DynaCT angiographic reconstruction technique, more target vessels were treated in a single BPA procedure (5.83 ± 2.33 vs 3.73 ± 1.10 vessels per BPA, p = 0.008) in a shorter operation time (3.58 ± 0.61 vs 4.49 ± 0.91h, p = 0.002). Overall, the dose area product (DAP) was significantly higher for the 2D group than for the 3D group (13,901.82 ± 5549.69 vs 4682.82 ± 1950.64, p < 0.001). The use of the DynaCT angiographic reconstruction technique to guide BPA required a lower dose of contrast agent (225.22 ± 48.70 vs 292.73 ± 76.82mL, p = 0.013) and less radiation exposure. The use of DynaCT angiographic reconstruction guidance in patients undergoing BPA is feasible and accurate. Images of DynaCT angiographic reconstruction may be beneficial for optimizing the operative process in BPA with reduced radiation exposure. • BPA guidance by DynaCT angiographic reconstruction is feasible and accurate. • DynaCT angiographic reconstruction may be beneficial for optimizing the operative process. • DynaCT angiographic reconstruction can reduce patient radiation dose due to multi-times of BPA sessions.

Patient radiation dose reduction using a commercial iterative reconstruction technique package

With 75.4% of the effective doses from imaging estimated to result from computed tomography (CT), it is the leading source of medical radiation. This important observation links with a further estimate that some 2% of all cancers are a result of medical imaging exposures. Acknowledging justification and optimization to be key towards preventing unnecessary radiation exposure, present study aims to investigate radiation exposures reduction for patients undergoing multiphase CT abdomen. Study was made of 111 CT examinations, use being made of two imaging protocols. Of these cases, 55 (49.5%) were obtained using a standard imaging protocol, the remainder being studied using the pure 3D SureExposure™ low-dose technique to obtain a complete abdomen multi-phase examination. Image quality was the subject of blind analysis by two experienced radiologists. For the standard imaging protocol, the mean and standard deviation for CTDIvol and DLP were respectively 7.2 ± 2.3 mGy and 1325 ± 605 mGy cm. For the pure 3D SureExposure™ low-dose technique the respective values were 5.2 ± 1.6 mGy and 812 ± 157 mGy cm. With an achieved mean dose reduction of up to 48%, use of the low dose techniques offers appreciable potential for dose saving without affecting the image quality.