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Basic Understanding of Medical Imaging Modalities
Published in Sanjay Saxena, Sudip Paul, High-Performance Medical Image Processing, 2022
Pradeep Kumar, Subodh Srivastava, Rajeev Srivastava
Fluoroscopy is an imaging process which has great real-time visualization of body structures by using x-rays. At the time of fluoroscopy, a real-time dynamic image is generated by emitting x-ray beams constantly and then is captured on a screen [5]. To allow high distinction between structures, a high anatomy density contrast agent will be launched into the patient; this allows the dynamic evaluation of function. Fluoroscopy is typically used for recognizing issues with barium studies, hysterical pornography (HSG), histography, and reduction of fractures under image guidance. Radiation doses from fluoroscopy are higher because of that pregnancy status must be known before the test. Children are more tactful to radiation so x-ray procedure should be performed with caution (Figure 1.2).
Radiation protection in medicine
Published in Alan Martin, Sam Harbison, Karen Beach, Peter Cole, An Introduction to Radiation Protection, 2018
Alan Martin, Sam Harbison, Karen Beach, Peter Cole
Fluoroscopy is also used during interventional procedures so that, for example, a surgeon can view procedures being undertaken inside the body of the patient. A modern fluoroscopic facility is shown in Figure 16.2. From a staff protection viewpoint, an important consideration is that the surgeon's hands may be close to the X-ray beam for appreciable periods of time and the resulting ‘extremity’ doses need to be monitored and controlled. In addition, a significant amount of radiation is backscattered from the patient and medical staff within approximately 2 m of the patient must wear lead aprons and, if required, lead thyroid shields. It may also be necessary for them to make use of lead-glass spectacles or a lead-glass screen to protect their eyes.
X-ray Vision: Diagnostic X-rays and CT Scans
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
A radiograph is a representation of anatomy at a particular moment in time. Fluoroscopy is a form of real-time x-ray imaging used for imaging motions within the body, and for many interventional procedures done under x-ray guidance (Figure 5.21a). For example, fluoroscopy must be used to follow the catheter's progress through the body in the cardiac catheterization techniques discussed earlier (Figure 5.16c). This dynamic imaging technique typically uses fluorescent materials to convert x-rays into visible light on a phosphor screen (Figure 5.21b). However, the dim resulting image is difficult to see when safe radiation exposures are used. Traditional fluoroscopy units employ a device called an image intensifier to increase the brightness of the original dim image (Figure 5.21c). In an image intensifier, the fluorescent screen is placed against a photocathode that converts the visible photons emitted by the screen into photoelectrons. These photoelectrons are accelerated and focused by electrical forces onto a second, smaller phosphor screen, where they form a tiny version of the original x-ray image. The brightness of the original image can be increased by a factor of 1000 to 500 by these two processes: the concentration of light intensity by focusing and the energy added to the photoelectrons. The resulting brighter image can be viewed directly, but it is more common to record it with a video camera and display it on a monitor. The resulting images can also be converted into an electronic format for further analysis by computer. Alternatively, fluoroscopy images can be recorded on detectors like those used for digital radiography.
Deep learning based tracked X-ray for surgery guidance
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2022
K. Bamps, Stijn De Buck, Joris Ector
Augmented reality (AR) systems are systems that combine real and virtual elements, registered in 3-D and with the ability to interact in real-time (Milgram et al. 1995). Estimating the pose of a X-ray device relative to the patient is a key process in many augmented reality (Zhao et al. 2020; Wang et al. 2020). Interventional fluoroscopy images can be fused with preinterventional 3-D patient data to enhance guidance and understand the surrounding structures of interest (Livyatan et al. 2003). This prevents the surgeon to exclusively rely on his mental mapping between the preoperative 3-D images and the 2-D fluoroscopic images. The registration between preoperative 3-D and 2-D fluoroscopy images could improve the clinical outcome of surgical procedures particularly in cardiac and endovascular procedures, radiation therapy, orthopaedics and trauma interventions (Otake et al. 2012; Gendrin et al. 2012; Mitrović et al. 2015; Hammami et al. 2020). However, the lack of fully automated frameworks for prediction of the 3-D pose of the C-arm with respect to the 3-D pre-operative data hinders the implementation of augmented reality applications in the clinic (Sutherland et al. 2019).