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. Author manuscript; available in PMC: 2024 Jul 31.
Published in final edited form as: Int J Radiat Oncol Biol Phys. 2023 Jan 18;116(4):927–934. doi: 10.1016/j.ijrobp.2023.01.007

Figure 4.

Figure 4.

Feasibility of BgRT based on clinical eligibility criteria. Mouse uptake data was rescaled according to body weight and injected dose to derive human-equivalent values. (A) The current X1 system requires the PET image to meet quantitative endpoints for BgRT to proceed. The activity concentration (AC) is the average tumor uptake within the 80% isocontour line, after background subtraction. The metric is shown for individual mice over time, with the 5 kB/cc threshold shows as a dashed line. (B) The normalized tumor signal (NTS) is the ratio of AC to the standard deviation within the background. The threshold for this metric is 2.7. (C) The passing rate represents the fraction of mice that met both AC and NTS criteria, and would theoretically be eligible for BgRT.