Simple calculation using anatomical features on pre-treatment verification CT for bladder volume estimation during radiation therapy for rectal cancer

Table 3 Comparison between bladder volumes estimated using bladder scan and using anatomical features on cone-beam computed tomography

Estimation tool	Number of data sets	Mean percent difference	95% CI	SD of percent difference	P
V_scan	108	33.2	28.5–37.8	26.7	< 0.001
V_ratio	108	23.4	21.3–29.5	21.4

Abbreviations: CI confidence interval, SD standard deviation, V_scan bladder volume measurement using bladder scan, V_ratio bladder volume measurement using ratio of anatomical features

ISSN: 1471-2407