FIG. 6.
(a) Contrast-to-noise ratio (CNR) vs. noise level in phantom from (σ) 0 to 0.04. No tumor motion was introduced, and the radius of the tumor was fixed at 5 mm. (b) CNR vs phantom tumor size, with the radius varying from 2 to 30 mm, compared with the radius under zero motion and the radius fixed at 5 mm (bottom). (c) CNR vs phantom tumor motion, simulated from 0 to 5 mm for tumor size, with a radius of 5 mm. The noise level and radius of the tumor were kept at 0.01 and 5 mm, respectively.