For example, given MLD = 33 Gy for the XRT plan versus 20 Gy for the PBT plan in patients with HCC, CP-A and negative hepatitis status, the estimated NTCP33 Gy is 39.6% (95% CI 23.4–57.0), NTCP20 Gy is 26.5% (95% CI 17.2–37.9) and ∆NTCP is 13.1% (95% CI 3.0–24.8). The gene discussed is CPA1; the disease is hepatocellular carcinoma.