Page 120 - Cellular Imaging in Regenerative Medicine, Cancer and Osteoarthritis

Chapter 5
allows for gross tumor localization by detection of γ-photons outside of the body, but this method is not suited for accurate tumor delineation during surgery [44]. On the other hand, fluorescence imaging is limited by the penetration depth of fluorescent light, which can only be detected when at close distance. However, fluorescence imaging does allow exact tumor delineation and can provide real-time intra-operative visualization [44]. Combining the strengths of radio-guided and fluorescence guided surgery can therefore be of benefit.
SPECT/MR imaging resulted in successful identification of tumor lesions on scans and, as expected, higher radioactivity uptake was visualized when [111In] SB3 was co-administered with PA. Time activity curves obtained with ex vivo biodistribution studies and ROI analysis on SPECT/MR images demonstrated similar patterns, indicating the SPECT/MRI platform to correctly depict the pharmacokinetics of the radiotracer.
With respect to the commercially available NEP inhibitor PA, to date preclinical studies evaluating its potential in potentiating the use of radiotracers have not indicated any adverse events [5, 28]. For application in patients NEP inhibitors that are already approved for clinical use such as Sacubitril and Racecadotril might be applied [45].
Furthermore, depending on the cancer type for which [111In]SB3 + PA will be used for tumor detection pre- and intra-operatively, the application should be compared to that using other radiotracers under investigation or applied for similar purposes, e.g. lymphoscintigraphy for sentinel lymph node biopsy in breast cancer patients and PSMA radio-guided surgery in prostate cancer patients [21, 46].
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