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Single-Photon Emission Computed Tomography
Published in George C. Kagadis, Nancy L. Ford, Dimitrios N. Karnabatidis, George K. Loudos, Handbook of Small Animal Imaging, 2018
In the arena of reconstruction, a variety of problems still need to be tackled. While there is little attenuation in the mouse at 141 keV, a significant fraction of photons from iodine-125 will scatter once before leaving the mouse model. By migrating back to transport models, effective reconstruction strategies may be possible in situations where energy resolution is useless (Gallas and Barrett 1998). Another interesting area of exploration is synergistic image formation in dual-modality imaging systems. One particularly attractive approach is the utilization of a priori information from a high-registration MR image when performing a limited-FOV SPECT reconstruction (Lee et al. 2011). Lee and colleagues reported that the root-mean-square error due to out-of-field artifacts could be reduced by at least 50% in this approach. Other groups have also reported the development of MR-compatible SPECT systems (Hamamura et al. 2010; Meier et al. 2011). Optical imaging and SPECT are also routinely combined in the same platform (Wang et al. 2012; van Oosterom et al. 2014), particularly if some component of the optical contrast agent can be radiolabeled (Culver et al. 2008; Tian et al. 2008; Liu et al. 2011; Lu et al. 2014; Lutje et al. 2014). The U-SPECT system has successfully integrated with both bioluminescence and fluorescence imaging (van Oosterom et al. 2014), although the optical imaging modalities were not fully tomographic. As described in Chapter 10 in this handbook, Cerenkov luminescence imaging, the optical imaging of certain radiotracers, may complement limited-view single-photon nuclear medicine imaging. As with other imaging modalities, compressive sensing strategies also present opportunities for “doing more with less” (Wolf et al. 2011; Mukherjee et al. 2014).
Determination of experimental Cherenkov spectrum (200–1050 nm) of 18F and its implications on optical dosimetry: murine model
Published in Radiation Effects and Defects in Solids, 2022
Eugenio Torres-García, Hansel Torres-Velazquez, Luis E. Díaz-Sánchez, Liliana Aranda-Lara, Keila Isaac-Olivé
Currently, optical imaging (OI) technique represents a challenge that is being addressed worldwide. This technique uses light to obtain detailed images of organs and smaller structures such as cells and even molecules (1,2). In addition, light has been used as a treatment for disease through photodynamic therapy (3). The Cherenkov effect is the production of light by electrons or beta particles when they pass through a dielectric medium (such as tissue) at a speed greater than that of light in the same medium (4). Cherenkov radiation has been useful to perform OI for Positron Emission Tomography (PET) radionuclides as Fluor-18 (18F), Carbon-11 (11C), Copper-64 (64Cu), Gallium-68 (68Ga), Zirconium-89 (89Zr), etc. (5–7). Also, Cherenkov luminescence imaging modality takes advantage of optical Cherenkov photons, since this light might be used for photoactivation, photodynamic therapy, photothermal therapy, excited fluorophores, etc. (8–10).