Table 3. Pearson correlation factors between conventional 2D and dose-volume parameters .

Variable	PCF (P-value)
CLD vs. DVH (ipsilateral lung)
V5Gy (%)	0.504 (< 0.001)
V10Gy (%)	0.593 (< 0.001)
V20Gy (%)	0.651 (< 0.001)
Dmean (Gy)	0.374 (< 0.001)
MLD vs. DVH (ipsilateral lung)
V5Gy (%)	0.492 (< 0.001)
V10Gy (%)	0.556 (< 0.001)
V20Gy (%)	0.637 (< 0.001)
Dmean (Gy)	0.610 (< 0.001)
MHL vs. DVH (heart)
V5Gy (%)	0.298 (0.019)
V10Gy (%)	0.301 (0.018)
V20Gy (%)	0.313 (0.013)
V25Gy (%)	0.402 (0.001)
Dmean (Gy)	0.361 (0.004)
MHD vs. DVH (heart)
V5Gy (%)	0.669 (< 0.001)
V10Gy (%)	0.656 (< 0.001)
V20Gy (%)	0.626 (< 0.001)
V25Gy (%)	0.690 (< 0.001)
Dmean (Gy)	0.668 (< 0.001)
CWS vs. DMax breast	0.103 (0.427)

CLD: Central lung depth; DVH: Dose-volume histogram; MLD:

Maximum lung depth; MHL: Maximum heart length; MHD:

Maximum heart distance; V_x: Volume of lung or heart receiving xGy;

D_mean: Mean dose; CWS: Chest wall separation; D_max: Maximum dose

PCF: Pearson correlation factor

PCF significant if P ≤ 0.01; PCF ≥ 0.7: Good correlation;

PCF ≥ 0.5 and < 0.7: Moderate correlation.

PCF < 0.5: Poor correlation.