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Optical Nanoprobes for Diagnosis
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
R. G. Aswathy, D. Sakthi Kumar
The advances in bioimaging technology have led to successful clinical diagnosis, resulting in significant progress in healthcare. Commonly employed clinical imaging modalities for diagnosis include magnetic resonance (MR), X-ray computer tomography (X-ray CT), ultrasound (US) imaging, etc. All these imaging modalities offer precise and high quality structural and anatomical data of the diseased tissue or organ. However, for detailed information at molecular and cellular level, optical imaging with superior contrast plays a critical role that is essential for the early detection and progression of several diseases (e.g., cancer), precise diagnosis, and for image-guided treatment of diseases (theranostic applications). The advancement in nanotechnology has led to several varieties of nanomaterials with unique optical properties leading to the development of optical nanoprobes. The versatility of these optical nanoprobes is improved by the integration of specific ligands, which, in turn, transforms the chemical data to optical signals that further enable the detection through various modes. Nanomaterial-based optical nanoprobes have several advantages, including superior sensitivity and specificity, ease of quantitative and qualitative detection of species in analysis, and early detection of several diseases. This chapter discusses different types of optical nanoprobes for diagnosis.
The Scintillation Camera
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
The scintillation camera, commonly referred to as a gamma camera, is a medical device designed to image the distribution of radiopharmaceuticals in vivo. Its invention is attributed to Hal Anger at the Donner Laboratory at the University of California, Berkley, in the early 1950s. The appearance of the modern camera is quite different to that used to produce the first clinical images. However, the fundamentals of the technology used for image acquisition and formation remain largely unchanged. Figure 13.1a is an illustration of a scintillation camera, highlighting the key components required for clinical imaging. The primary components used for photon detection are located within a shielded housing (referred to as the detector or head), supported on a rotating gantry (Figure 13.1b). Gamma cameras usually have two detectors, although single- and triple-headed systems are available. A brief summary of the function of each component is summarized in Table 13.1 and discussed in more detail in this chapter.
Artificial Intelligence Based COVID-19 Detection using Medical Imaging Methods: A Review
Published in S. Prabha, P. Karthikeyan, K. Kamalanand, N. Selvaganesan, Computational Modelling and Imaging for SARS-CoV-2 and COVID-19, 2021
M Murugappan, Ali K Bourisly, Palani Thanaraj Krishnan, Vasanthan Maruthapillai, Hariharan Muthusamy
Diagnosis of COVID-19 relies on the following criteria: (a) clinical symptoms; (b) clinical imaging (i.e., Computed Tomography (CT) and general X-Ray images); (c) nucleic acid test/pathogenic testing; (d) close contact history; (e) contact history with patients with fever; (f) clustering occurrence; and (g) epidemiological history (Sana et al. 2020, Radiology assistant 2020). The standard test recommended by the WHO to diagnose COVID-19 is the Nucleic Acid Amplification Test (NAAT) and RT-PCR (Hao & Li 2020, EUA-COVID-19 2020). Sudden increase in levels of C-reactive protein and ESR is used as an additional tool for diagnosing COVID-19. Significant limitations of RT-PCR testing are: (a) many countries do not have abundant access to sophisticated labs and appropriate laboratory tools to perform this test; (b) the test is supposed to be repeated 2 to 3 times to validate the accuracy of results; (c) limited access to virologists and epidemiologists in many countries slows down the diagnosis process; (d) turnaround time to get the results of RT-PCR can be up to 72 hours for one sample; (e) testing is expensive and could not be afforded by developing countries; and (f) finally, it is minimally invasive (Soon et al. 2020). The above limitations of RT-PCR are also valid for the NAAT test; however, if the viral load is low while testing, the NAAT test results will be negative (Ying et al. 2020). All the above issues significantly delay the diagnosis process. Early isolation stops the spread and allows treatment to start early.
Dimensions of artefacts caused by cochlear and auditory brainstem implants in magnetic resonance imaging
Published in Cochlear Implants International, 2020
Elham Majdani, Omid Majdani, Melanie Steffens, Athanasia Warnecke, Anke Lesinski-Schiedat, Thomas Lenarz, Friedrich Götz
Table 1 gives an overview of the CE approved MRI modalities for different cochlea implant manufacturers, implant series and field strengths (‘http://www.advancedbionics.com/content/dam/ab/Global/en_ce/documents/libraries/Professional%20Library/AB%20Product%20Literature/System_Indications_Precautions/Warnings_and_Precautions.pdf’, ‘http://www.cochlear.com/wps/wcm/connect/intl/home/support/cochlear-implant-systems/global-warnings’, ‘http://www.medel.com/cochxlear-implants-mri-safety/’, ‘http://www.medel.com/isi-cochlear-implant-systems/’). The latest generation of CI from all manufacturers offers the option to surgically remove the magnet for artefact reduction during MRI examination. As most MRI examinations are still using a field strength of 1.5 T (Crane et al., 2010; Migirov and Wolf, 2013; Nospes et al., 2013; Wackym et al., 2004; Walton et al., 2014), we focused our clinical study accordingly. The goal of our study was to analyse artefacts in CI patients. We measured dimensions of observed artefacts and distortion of anatomical structures during clinical imaging.
Evaluating the safety profile of focused ultrasound and microbubble-mediated treatments to increase blood-brain barrier permeability
Published in Expert Opinion on Drug Delivery, 2019
Dallan McMahon, Charissa Poon, Kullervo Hynynen
There have been efforts to develop strategies for determining equivalent MB doses. Song et al. have proposed gas volume to be a unifying parameter, demonstrating a strong correlation between gas volume and Evans blue extravasation following sonication when comparing MBs with mean diameters of 2 and 6 μm [78]. It is unclear if this relationship holds true between MBs with different shell compositions or for MBs with wide size distributions. Another approach has been to use the clinical imaging dose of MBs as a normalizing factor. McDannold et al. found that the probability of increased BBB permeability as a function of pressure amplitude was similar between the clinical imaging doses of Definity and Optison [84]. While these methods may have value in approximating equivalent doses, the development of more robust dose-equivalence strategies remains an unresolved issue, though continued advancement of acoustic control schemes, may alleviate some of this need.
Cochlear helix and duct length identification – Evaluation of different curve fitting techniques
Published in Cochlear Implants International, 2018
Daniel Schurzig, Max Eike Timm, G. Jakob Lexow, Omid Majdani, Thomas Lenarz, Thomas S. Rau
In general, measurement accuracy is dependent on the resolution of the clinical imaging data, which is limited by the capabilities of currently available, clinically applicable imaging devices. Future developments may further improve clinical diagnostics based on the radiological data. If available, it may also be possible to merge preoperative CBCTs with other radiological datasets: the additional visualization of soft tissue by registered magnetic resonance imaging data, for instance, could yield improved visibility of the cochlear partition such that more distinct statements on the geometry of the actual structure of interest for CI surgery, i.e. the ST, can be made. However, it may be necessary to adjust the standard scanning procedure in order to make the imaging data useful for cochlear geometry evaluations such as patient fixation during the increased scanning time and the employment of a modified scanning protocol.