Knowing how to count breathing can help detect pneumonia quickly and accurately to have a treatment plan, timely intervention, and prevent dangerous complications that may occur. Especially for newborns who often have periodic breathing, monitoring their breathing to detect pneumonia is very necessary.

Breathing is an important activity to maintain life. Because this is the process of providing oxygen to the brain and other organs of the body. When the breathing frequency is affected by disease or risk factors, it can bring many disadvantages to people, even threatening their lives.

Objective: Evaluation daily setting error using 3D-CBCT image data to determine Setupmargin in 4D-DIBH radiotherapy (end-inspiratory hold) for left breast cancer.