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Spectral CT Imaging Using MARS Scanners
Published in Katsuyuki Taguchi, Ira Blevis, Krzysztof Iniewski, Spectral, Photon Counting Computed Tomography, 2020
Aamir Y. Raja, Steven P. Gieseg, Sikiru A. Adebileje, Steven D. Alexander, Maya R. Amma, Fatemeh Asghariomabad, Ali Atharifard, Benjamin Bamford, Stephen T. Bell, Srinidhi Bheesette, Anthony P. H. Butler, Philip H. Butler, Pierre Carbonez, Alexander I. Chernoglazov, Shishir Dahal, Jérôme Damet, Niels J. A. de Ruiter, Robert M. N. Doesburg, Brian P. Goulter, Joseph L. Healy, Praveen K. Kanithi, Stuart P. Lansley, Chiara Lowe, V. B. H. Mandalika, Emmanuel Marfo, Aysouda Matanaghi, Mahdieh Moghiseh, Raj K. Panta, Hannah M. Prebble, Nanette Schleich, Emily Searle, Jereena S. Sheeja, Rayhan Uddin, Lieza Vanden Broeke, V. S. Vivek, E. Peter Walker, Michael F. Walsh, Manoj Wijesooriya
Other current molecular imaging modalities, especially positron-emission tomography (PET), single photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), and optical, have strengths for viewing biological processes at the molecular and cellular levels but are still far from capturing the whole picture in a majority of cases. PET-CT is the principal spectroscopic imaging modality in current use. It has an exquisite sensitivity (ng/mL) due to the radioactive isotopes used, but in general is not chemically or tissue specific; the nature of the tissue identified has to be inferred from an anatomical or clinical context. MRI has excellent soft tissue contrast but is slow, has poor spatial resolution, and cannot be used for patients with either claustrophobia or metallic implants. Optical molecular imaging is sensitive and specific but its limited penetration depth prevents it from being translated for most clinical tasks.
Pet/Ct
Published in George C. Kagadis, Nancy L. Ford, Dimitrios N. Karnabatidis, George K. Loudos, Handbook of Small Animal Imaging, 2018
Mohammad Reza Ay, Nafiseh Ghazanfari
In the last decades, advanced demand in biomedical research and interest in knowing more about the base function of the human body, like functional operation of the cells’ system or their organism, has increased the interest in understanding pathophysiologic and physiological processes that advent a new field of research as molecular imaging. Utilizing different imaging modalities accelerate the advancement of investigation for new imaging markers and procedure of probing disease. Different molecular imaging systems and techniques such as positron emission tomography (PET), single photon emission computed tomography (SPECT), computed tomography (CT), magnetic resonance imaging (MRI) in its various forms such as magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI), functional MRI (fMRI), and ultrasound (US), optical bioluminescence/fluorescence have been developed in the past few years for animal studies purposes (Figure 12.1). Applications of the mentioned imaging techniques vary accordingly to their ability in detecting the structure of considered tissue (Sossi 2011; Levin 2012).
Molecular image guided radiotherapy
Published in Michael C. Joiner, Albert J. van der Kogel, Basic Clinical Radiobiology, 2018
Vincent Grégoire, Karin Haustermans, John Lee
Molecular imaging, also referred to as biological imaging or functional imaging, is the use of non-invasive imaging techniques that enable the visualization of various biological pathways and physiological characteristics of tumours and/or normal tissues. In short, it mainly refers (but not only) to positron emission tomography (PET) and magnetic resonance imaging (MRI). In clinical oncology, molecular imaging offers the unique opportunity to allow an earlier diagnosis and staging of the disease to contribute to the selection and delineation of the optimal target volumes before and during (i.e. adaptive treatment) radiotherapy and to a lesser extent before surgery, to monitor the response early on during the treatment or after its completion, and to help in the early detection of recurrence. From the viewpoint of experimental radiation oncology, molecular imaging may bridge radiobiological concepts such as tumour hypoxia, tumour proliferation, tumour stem cell density and tumour radiosensitivity by integrating tumour biological heterogeneity into the treatment planning equation (Figure 22.1). From the viewpoint of experimental oncology, molecular imaging may also facilitate and speed up the process of drug development by allowing faster and cheaper pharmacokinetic and biodistribution studies.
Molecular imaging in management of colorectal metastases by the interventional oncologist
Published in International Journal of Hyperthermia, 2022
Stephen Hunt, Alireza Zandifar, Abass Alavi
Real-time PET-CT can also be utilized for more accurate targeting during tumor ablation, however several considerations must be made. First, ablation does not get rid of the FDG tracer activity, and intraprocedural post-thermal ablation imaging can continue to demonstrate tracer activity in the tumor [35]. This persistence, however, can be utilized to examine post-ablation margins by combining intraprocedural FDG-PET-CT imaging with post-ablation contrast-enhanced CT or a PET perfusion agent such as nitrogen-13 ammonia PET [36]. An FDG split-dose technique has been described which uses a small initial dose of FDG for tumor localization and targeting, and a larger post-ablation dose for immediate assessment of residual viable tumor (Figure 2) [37]. This allows for additional targeting of the lesion, and post ablation FDG activity has been demonstrated to correlate with biopsy-positive tumor margins and recurrence [38]. Most recently, a split-dose technique has been described which combines an initial pre-ablation FDG-PET dose for tumor localization followed by a second FDG-PET dose used as a perfusion agent for post-ablation margin assessment [39]. Of course, any benefits to the use of intraprocedural molecular imaging must be balanced against the cost in procedural resources, time, personnel, and additional radiation dose to the treatment team [24].
Emerging theranostics to combat cancer: a perspective on metal-based nanomaterials
Published in Drug Development and Industrial Pharmacy, 2022
Tejas Girish Agnihotri, Shyam Sudhakar Gomte, Aakanchha Jain
Molecular imaging (MI) is the field that deals with monitoring and measuring the biological processes in living subjects with the aid of spectral data. It is a similar technique to biopsy; however, it is performed in a noninvasive manner, in real-time imaging for stepwise and longitudinal monitoring. In the clinic, molecular imaging allows clinicians to look within the body to detect diseases, track their progression, and treat diverse types of disorders on a molecular level. With the introduction of specific molecular probes, molecular imaging offers early detection of cancer-related abnormalities and considers novel targeted therapeutics [20]. Conventional approaches such as computed tomography (CT) and, X-ray generate the anatomical image. On the other hand, MI tools like single-photon emission CT (SPECT), positron emission tomography (PET), magnetic resonance spectroscopy (MRI), optical techniques, and contrast-enhanced CT techniques not only provide us with anatomical images but also give images based on physiological functions [13].
Potential application of mass spectrometry imaging in pharmacokinetic studies
Published in Xenobiotica, 2022
Chukwunonso K. Nwabufo, Omozojie P. Aigbogun
Several molecular imaging platforms that can be used to visualise and quantify drugs at disease target tissues are available, but each has its disadvantages as previously described (Willmann et al. 2008). Optical imaging has limited clinical translation, low depth of penetration, and the probes utilised (e.g. fluorescent probe) could affect the drug PK profile. Magnetic resonance imaging (MRI) is costly and has a high imaging time while imaging using ultrasound technique is limited to the vasculature. Other sophisticated imaging modalities such as positron emission tomography and single-photon-emission computed tomography are limited by the high cost and low spatial resolution (Nwabufo and Aigbogun 2022). On the other hand, computed tomography lacks target specificity and has low soft-tissue contrast. Similarly, autoradiography is costly, has a long imaging time, and suffers from specificity issues due to challenges with distinguishing the radioactivity coming from parent compound and their associated degradation products or metabolites (Spruill et al. 2022). Given that many of these molecular imaging techniques including positron-emission tomography and single-photon-emission computed tomography require the use of radioactive isotopes, it is prone to numerous health and environmental hazards.