Dose Course 2018_Flipping book

27

Summary

❑ The dose discrepancy could be up to 10-15% due to the large difference between the stopping powers of water and these higher-density materials i.e. bone. o vertebrae, mandible, femoral heads…

❑ For soft tissues and lung, the dose discrepancy is only about 1 to 2%

❑ For air the discrepancy could be around 10-12% o air cavities in PTV, trachea, air cavities in intestines, rectum

o Do we need to define air, is it OK with very low density soft tissue/water???

Slide inspired by N Reynaerts from his ESTRO 35 lecture

Dublin 2018