Example DVH Comparison: IMRT-SIB versus 3DCRTfor: (a) PTV1; (b) PTV2; (c) TL-CTV1; (d) cord; (e) liver; (f) heart (same patient as Figure1). IMRT-SIB (thick lines) and 3DCRT (thin lines) are compared directly for a single illustrative case. IMRT-SIB is more conformal about PTV1 than 3DCRT, with a lower mean dose and a more pronounced dose-gradient from PTV1 to PTV2. There is similar coverage of PTV2. For TL-CTV1 and liver, 3DCRT has better dosimetry in the low-dose region but is worse in the higher-dose region. IMRT-SIB delivers consistently better dosimetry to the heart and the cord over the entire range of dose.