Evaluation of Methods of Displaying the Real-Time Scattered Radiation Distribution during Fluoroscopically-Guided Interventions for Staff Dose Reduction.

2D and 3D scatter dose display options are evaluated for usefulness and ease of interpretation for real-time feedback to staff to facilitate changes in individual positioning for dose reduction purposes, as well as improving staff consciousness of radiation presence. Room-sized scatter dose 3D matrices are obtained utilizing Monte Carlo simulations in EGSnrc. These distributions are superimposed on either a ceiling-view 2D graphic of the patient and table for reference or a 3D augmented reality (AR) display featuring a real-time video feed of the interventional room.

Investigation of organ dose variation with adult head size and pediatric age for neuro-interventional projections.

The purpose of this study was to evaluate the effect of patient head size on radiation dose to radiosensitive organs, such as the eye lens, brain and spinal cord in fluoroscopically guided neuro-interventional procedures and CBCT scans of the head. The Toshiba Infinix C-Arm System was modeled in BEAMnrc/EGSnrc Monte-Carlo code and patient organ and effective doses were calculated in DOSxynrc/EGSnrc for CBCT and interventional procedures. X-ray projections from different angles, CBCT scans, and neuro-interventional procedures were simulated on a computational head phantom for the range of head sizes in the adult population and for different pediatric ages.

Gantry rotational motion-induced blur in cone-beam computed tomography.

As neuro-endovascular image-guided interventions (EIGIs) make use of higher resolution detectors, gantry rotational motion-induced blur becomes more noticeable in acquired projections as well as reconstructed images by reducing the visibility of vascular and device features whose visualization could be critical in the treatment of vascular pathology. Motion-induced blur in projections views is a function of an object's position in the field-of-view (FOV), gantry rotational speed, and frame capture or exposure time. In this work different frame rates were used to investigate the effects of blurring from individual projections on the reconstructed image.

Use of material decomposition in the context of neurovascular intervention using standard flat panel and a high-resolution CMOS detector.

The imaging of endovascular devices during neurovascular procedures such as the coiling of aneurysms guided with CBCT imaging may be challenging due to the presence of highly attenuating materials such as platinum in the coil and stent marker, nickel-titanium in the stent, iodine in the contrast agent, and tantalum in the embolization agent. The use of dual-energy imaging followed by a basis material decomposition image processing-scheme may improve the feature separation and recognition. Two sets of testing were performed to validate this concept.

3D Printed Cardiovascular Patient Specific Phantoms Used for Clinical Validation of a CT-derived FFR Diagnostic Software.

Purpose: 3D printed patient specific vascular models provide the ability to perform precise and repeatable benchtop experiments with simulated physiological blood flow conditions. This approach can be applied to CT-derived patient geometries to determine coronary flow related parameters such as Fractional Flow Reserve (FFR). To demonstrate the utility of this approach we compared bench-top results with non-invasive CT-derived FFR software based on a computational fluid dynamics algorithm and catheter based FFR measurements.

Developing a database of 3-D scattered radiation distributions for a c-arm fluoroscope as a function of exposure parameters and phantom.

The purpose of this work is to develop a database of 3D scattered radiation dose-rate distributions to estimate the staff dose by location around a C-Arm fluoroscopic system in an interventional procedure room. The primary x-ray beam of a Toshiba Infinix fluoroscopy machine was modeled using EGSnrc Monte Carlo code and the scattered radiation distributions were calculated using 5 × 10 photons per simulation. These 3D distributions were determined over the volume of the room as a function of various parameters such as the beam kVp and beam filter, the size and shape of the field, the angulation of the C-arm, and the phantom size and shape.

Use of a CMOS-based micro-CT system to validate a ring artifact correction algorithm on low-dose image data.

The imaging of objects using high-resolution detectors coupled to CT systems may be made challenging due to the presence of ring artifacts in the reconstructed data. Not only are the artifacts qualitatilvely distracting, they reduce the SNR of the reconstructed data and may lead to a reduction in the clinical utility of the image data. To address these challenges, we introduce a multistep algorithm that greatly reduces the impact of the ring artifacts on the reconstructed data through image processing in the sinogram space.