ABSTRACT
Objective To investigate the differences in dosimetry between conformal radiotherapy (CRT),field-in-field intensity-modulated radiotherapy (FIF-IMRT),and intensity-modulated radiotherapy (IMRT) after breast-conserving surgery for left-sided breast cancer.Methods A total of 31 patients who underwent breast-conserving surgery for left-sided breast cancer were randomly selected,and the plans for CRT,FIF-IMRT,and IMRT were developed.The dose-volume histogram (DVH) was used for self-control study,and the non-parametric test was used to compare the differences in target volume and doses to organs at risk (OARs).Results All the three methods met the requirements of the prescribed doses.The CRT group had a higher V105 of the target volume and higher heart V30 and Dmax (P=0.000,0.000,0.000).The IMRT group had higher V5 and Dmean (P=0.000,0.000),as well as a higher lung V5 and a lower lung V40 (P=0.000,0.000).The FIF-IMRT group had the lowest Dmean (P=0.000),and the IMRT group had significantly higher Dmean and Dmax of the right lung and the spinal cord than the other two groups (P=0.000,0.000,0.000,0.000).The FIF-IMRT group had a significantly lower single hop count than the other two groups (P=0.000).Conclusions CRT has a good dose distribution in the target volume,but greatly injures the surrounding tissues.FIF-IMRT can well protect OARs and cause less damage to the device.