Recently, carbon fiber (CF) has prevailed as the primary material used in radiotherapy couchtops. Modern couchtops incorporate the CF sandwich design, in which 2 thin CF plates sandwich an air-equivalent polymeric foam. Developments in radiotherapy necessitate irradiation from posterior angles through the couchtop.
View Article and Find Full Text PDFThis study establishes typical Diagnostic Reference Levels (DRL) values and assesses patient doses in computed tomography (CT)-guided biopsy procedures. The Effective Dose (ED), Entrance Skin Dose (ESD), and Size-Specific Dose Estimate (SSDE) were calculated using the relevant literature-derived conversion factors. A retrospective analysis of 226 CT-guided biopsies across five categories (Iliac bone, liver, lung, mediastinum, and para-aortic lymph nodes) was conducted.
View Article and Find Full Text PDFRadiat Prot Dosimetry
February 2024
In this study, the effect of patient- and procedure-related parameters on organ doses (ODs), peak skin dose (PSD) and effective dose (E) during anterior cervical discectomy and fusion (ACDF) was evaluated. Patient- and procedure-related parameters, as well as fluoroscopy time, kerma-area product (KAP), cumulative air-kerma (Kair) and incident Kair, were analysed for 50 ACDF procedures performed with a mobile C-arm. These parameters were inserted in VirtualDose-IR software implementing sex-specific and body mass index (BMI)-adjustable anthropomorphic phantoms to calculate OD, PSD and E.
View Article and Find Full Text PDFBiomed Phys Eng Express
September 2023
. To establish institutional diagnostic reference levels (IDRLs) based on clinical indications (CIs) for three- and four-phase computed tomography urography (CTU)..
View Article and Find Full Text PDFThis work aimed to develop and validate software that calculates the shielding thickness required for a radiotherapy room with a linear accelerator utilising geometric and dosimetric data. The software "Radiotherapy Infrastructure Shielding Calculations" (RISC) was developed using MATLAB programming. It does not require the installation of the MATLAB platform, and the user only needs to download and install the application, which displays a graphical user interface (GUI).
View Article and Find Full Text PDFThe GORE EXCLUDER Conformable abdominal aortic aneurysm (AAA) Endoprosthesis (CEXC), is currently the newest stent-graft system for treating patients with AAA. CEXC is approved for patients with proximal aortic neck angles ≤90° with a ≥15 mm aortic neck length or proximal aortic neck angles ≤60° with ≥10 mm aortic neck length. The present study describes a clinical series of 5 males with AAA, one of whom had a ruptured infrarenal AAA and a 90° proximal aortic neck angle.
View Article and Find Full Text PDFIn this study, the effect of patient- and procedure-related parameters on organs' dose (OD), peak skin dose (PSD) and effective dose (ED) during lumbar discectomy and fusion (LDF) was assessed. Intra-operative parameters obtained from 102 LDFs were inserted into VirtualDose-IR software implementing sex-specific and BMI-adjustable anthropomorphic phantoms for dosimetric calculations. Fluoroscopy time (FT), kerma-area product (KAP), cumulative and incident air-kerma (K) were also recorded from the dosimetric report of the mobile C-arm.
View Article and Find Full Text PDFIn this study, the effect of body-mass-index (BMI) on organ doses (ODs) during infrarenal endovascular-aneurysm-repair (EVAR) procedures was evaluated. Patient- and intra-operative data from fifty-nine EVAR procedures were inserted into VirtualDose-IR software to calculate ODs. For overweight, obesity class-I and obesity class-II, ODs were up to 147%, 412% and 775% higher than those for normal weight-patients, respectively.
View Article and Find Full Text PDFPatients who undergo endovascular aortic aneurysm repair (EVAR) may require prolonged radiation exposure affected by several factors. The objectives of this study were to document fluoroscopy time (FT) during EVAR and identify possible factors that influence it. A retrospective analysis of a 180 patients' database with abdominal infrarenal aortic aneurysms submitted to EVAR during a 7-y period was performed.
View Article and Find Full Text PDFAutomatically measuring a muscle’s cross-sectional area is an important application in clinical practice that has been studied extensively in recent years for its ability to assess muscle architecture. Additionally, an adequately segmented cross-sectional area can be used to estimate the echogenicity of the muscle, another valuable parameter correlated with muscle quality. This study assesses state-of-the-art convolutional neural networks and vision transformers for automating this task in a new, large, and diverse database.
View Article and Find Full Text PDFDeep learning (DL) is a well-established pipeline for feature extraction in medical and nonmedical imaging tasks, such as object detection, segmentation, and classification. However, DL faces the issue of explainability, which prohibits reliable utilisation in everyday clinical practice. This study evaluates DL methods for their efficiency in revealing and suggesting potential image biomarkers.
View Article and Find Full Text PDFIntroduction: Our purpose was to review the scientific literature and collect information regarding clinical and technical parameters of different single- or multiphase CT protocols, their diagnostic performance and patient dose during parathyroid imaging.
Evidence Acquisition: PubMed and Scopus databases were searched for studies investigating the diagnostic performance of CT in detecting parathyroid lesions and the corresponding patients' dose. The following information was retrieved for each article: CT system, number, combination and time interval between phases, scanning length, sensitivity, specificity, accuracy, positive and negative predictive values, contrast enhancement in Hounsfield Units (HUs), technical and exposure parameters, and dose indices.
Automatically delineating the deep and superficial aponeurosis of the skeletal muscles from ultrasound images is important in many aspects of the clinical routine. In particular, finding muscle parameters, such as thickness, fascicle length or pennation angle, is a time-consuming clinical task requiring both human labour and specialised knowledge. In this study, a multi-step solution for automating these tasks is presented.
View Article and Find Full Text PDFObjective: To estimate organs' absorbed dose from the two-phase CT of parathyroid glands, effective dose (ED) based on three different methods, and compare the dose values with those reported by other published protocols.
Methods: Volumetric-computed-tomography-dose-index (CTDI), dose-length-product (DLP), and the corresponding scan length during each phase of a parathyroid protocol were recorded, for seventy-six patients. One k-factor, and two different k-factors for the neck and chest area were used to estimate the ED from DLP.
Purpose: This paper reviews recent applications of Generative Adversarial Networks (GANs) in Positron Emission Tomography (PET) imaging. Recent advances in Deep Learning (DL) and GANs catalysed the research of their applications in medical imaging modalities. As a result, several unique GAN topologies have emerged and been assessed in an experimental environment over the last two years.
View Article and Find Full Text PDFThis study evaluates the patient radiation dose from the two-phase protocols of two different computed tomography (CT) systems and compares this with that delivered by the other similar protocols previously published. Two hundred and fourteen patients with primary hyperparathyroidism were included in the study with a two-phase CT scan between 2008 and 2020 by using a Toshiba Aquilion Prime 80 and a GE Light Speed 16. The standard 'neck' or a modified 'parathyroid' protocol was used.
View Article and Find Full Text PDFThis study aims to evaluate patient radiation dose during fluoroscopically guided endovascular aneurysm repair (EVAR) procedures. Fluoroscopy time (FT) and kerma-area product (KAP) were recorded from 87 patients that underwent EVAR procedures with a mobile C-arm fluoroscopy system. Effective dose (ED) and organs' doses were calculated utilising appropriate conversion coefficients based on the recorded KAP values.
View Article and Find Full Text PDFEarly and automatic diagnosis of Solitary Pulmonary Nodules (SPN) in Computed Tomography (CT) chest scans can provide early treatment for patients with lung cancer, as well as doctor liberation from time-consuming procedures. The purpose of this study is the automatic and reliable characterization of SPNs in CT scans extracted from Positron Emission Tomography and Computer Tomography (PET/CT) system. To achieve the aforementioned task, Deep Learning with Convolutional Neural Networks (CNN) is applied.
View Article and Find Full Text PDFPurpose: Accurate detection and treatment of Coronary Artery Disease is mainly based on invasive Coronary Angiography, which could be avoided provided that a robust, non-invasive detection methodology emerged. Despite the progress of computational systems, this remains a challenging issue. The present research investigates Machine Learning and Deep Learning methods in competing with the medical experts' diagnostic yield.
View Article and Find Full Text PDFPatient dose values varied significantly during interventional procedures, mainly due to the patient size, operators' choices and clinical complexity. In this study, the effect of applying a previously described and validated size-correction method to normalise kerma-area product (KAP) and average KAP rate values of the whole procedure (KAP rate) and isolate variations in dose due to the patient size and complexity, during lumbar discectomy and fusion (LDF) procedures, was investigated. Fluoroscopy time (FT), KAP, KAP rate and patient size data (weight, height and equivalent diameter) were recorded, for 96 patients who underwent single or multilevel LDF procedures by three senior neurosurgeons, defining three different patient groups (surgeon 1, surgeon 2, surgeon 3).
View Article and Find Full Text PDFBackground: Radiation exposure during endovascular repair (EVAR) of abdominal aortic aneurysms (AAAs) is a potential issue. Several studies have identified factors affecting radiation exposure, although they are limited. The aim of this study was to identify independent factors affecting radiation exposure in patients with AAA undergoing standard EVAR.
View Article and Find Full Text PDFA method for the theoretical estimation of the MTF of columnar phosphors with a homogeneous part at the end used in X-ray imaging has been developed. This method considers the light transport inside the scintillator through an analytical modelling, the optical photon beams distribution on the scintillator-optical sensor interface, and uses the definition of the PSF and a Gauss fitted LSF to estimate the MTF of an indirect detector. This method was applied to a columnar CsI:Tl scintillator and validated against experimental results found in literature, and a good agreement was observed.
View Article and Find Full Text PDFBackground: Sarcopenia is a common disease in the elderly. Although extensive research has been conducted on muscle mass and quality assessment tools, there are still certain drawbacks preventing their universal use.
Aim: The aim of this study was the evaluation of the thickness of head, neck, upper and lower limb muscles measured with ultrasonography, as a potential predictory tool in sarcopenia.
In this study, the radiation dose received by 364 low body mass index (BMI) adult patients undergoing chest, abdomen, lumbar spine, kidneys and urinary bladder (KUB) and pelvis X-ray examinations in an X-ray room with a digital radiography system was evaluated. The patients' kerma area product (KAP) values were recorded, and the entrance surface air kerma (ESAK) was calculated based on the X-ray tube output, exposure parameters and technical data. The 75th percentiles of the distribution of ESAK and KAP values were also estimated.
View Article and Find Full Text PDFThis study aims to clarify some of the issues associated with the reliable measurement of muscle thickness on ultrasonographic images of the musculoskeletal system, namely the repeatability of measurements in different time frames, the effect of body side selection, and the effect of scan orientation. Ultrasound scans were performed on muscles associated with essential daily activities: geniohyoid, masseter, anterior arm muscles, rectus femoris, vastus intermedius, tibialis anterior, and gastrocnemius. Measurements of the muscle thickness were performed and repeated after 1, 6, and 24 h, on both dominant and nondominant side, using both transverse and longitudinal scans.
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