ABSTRACT
Objective To compare the dose distribution between three dimensional conformal radiothera -py(3DCRT) and simplified intensity modulated radiotherapy ( sIMRT) for middle-third esopheagal cancer .Meth-ods Twenty middle-third esopheagal cancer patients were enrolled in this study .Dosimetric values for sIMRT and 3DCRT were calculated for total dose of 66 Gy using 2 Gy/day.The parameters included the conformal index (CI),homogeneity index(HI),mean dose and hot spot(V105%)for the planned target volume(PTV)as well as the monitor units(MUs)for plan efficiency,the mean dose(Dmean)for the organs at risk(OAR).The percentage of the normal lung volume receiving≥30,>20 and >5 Gy(V30 Gy,V20 Gy and V5 Gy)were evaluated to deter-mine lung toxity.Results sIMRT achieved significant better Dmin ,Dmean,V105%,HI,CI and spinal cord than 3DCRT(P<0.05).The normal lung V30 Gy and V20 Gy of 3DCRT and sIMRT were 11.61 ±3.68 vs.10.33 ± 3.02(P=0.010)and 23.37 ±8.38 vs.18.89 ±4.45(P=0.001),respectively.Comparable sparing of normal tissue including heart and the normal lung V 5 Gy with both two plans .The number of MU was 542 .24 ±76 .32 for 3DCRT and 530.8 ±97.13 for sIMRT(P=0.677).Conclusion sIMRT provides favorable tumor coverage , homogeneity and conformity and can get better normal lung sparing than 3DCRT.However sIMRT is not superior to 3DCRT in terms of treatment efficiency .
ABSTRACT
European countries have long history of medical education.Medical colleges have their independence in comprehensive universities and have high degree of standardization ad systematization in management.Besides,long schooling and high cost,small-size class teaching,good matrabulate quality and the combination of professional and part-time clinic teachers are the characteristics in their talent cultivation,which guarantee the medical education quality and can be used by us for reference.