Deep inspiration breath hold

Active Breathing Coordinator (ABC)

A major challange in radiotherapy is the breathing motion during the treatment. One option to reduce motion is repeated computer controlled deep inspiration breathhold (DIBH) with the Active Breathing Coordinator™ (Figure 1) .


Active Breathing Coordiantor 

Figure 1: Active Breathing Coordinator (ABC)


The systems allows the reduction of breathing motion during therapy. By blocking the airway preciseley when a predefined lung volume is reached anatomical immobilisation is achieved during irradiation. Utilizing this technique organs at risks (lung) can be spared better while aplying the full dose to the tumor with small safety margins (Figure 2).




Figure 2: Increased lung volume with DIBH CT (green) compared to free breathing CT (grey)



During the planning CT the whole procedure is explained to the patient and DIBH is trained multiple times. The achievable lung volume are set individually for each patient as well as the time for each realxing period inbetween consecutive breath holds. Because of the static situation relatively small safety margins can be utilized during the planing process. Before each fraction a cone beam CT (CBCT) is taken under DIBH to facilitate a high precision image guided radiation therapy. The irradiation is usually done with Flattening Filter Free (FFF) mode with dose rates of up to 2500 MU/min. Furthermore the treatment is done via a gating interface at the machine (Response™) to automatically stop and start the beam when the tumor is in the correct position. Using this technique a stereotactic body irradiation of 5 to 12 Gy per fraction can be treated in a few minutes.

The ABC can also be used for liver, breast and pancreas cancer.

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last modified: 17-Apr-15
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