Cerenkov luminescence imaging
Cerenkov light is produced when positrons (β+) or electrons (β-) travel through matter faster than the speed of light within that matter. Optical imaging can be used to assess the distribution of positron emitting radiopharmaceuticals such as [18F]FDG (Robertson et al., 2009; Spinelli et al., 2010).
PET imaging is limited to detecting the gamma rays emitted from annihilation events, which leads to relatively poor image resolution limited by the distance the positron travels in tissue before the annihilation. The higher the energy of the positron, the larger the average distance is. In contrast, the amount of Cerenkov light is larger with high-energy positrons, and the source of Cerenkov light is closer to the position of the original decay event, providing better resolution images of the distribution of the radiopharmaceutical. On the other hand, Cerenkov luminescence imaging is limited by the high attenuation and scatter of light in tissues, while gamma rays that are detected by PET pass much better through tissues allowing better imaging of locations deep inside the body. Therefore Cerenkov luminescence imaging is most useful in studies of small animals, but applications in clinical human studies are still possible (Thorek et al., 2014; Grootendorst et al., 2017).
Red blood cells absorb the red and infrared Cerenkov light, causing reduced signal in blood vessels. Negative contrast Cerenkov luminescence imaging takes advantage of this in imaging of blood vessels (Steinberg et al., 2014).
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Updated at: 2022-01-18
Created at: 2022-01-18
Written by: Vesa Oikonen