Deep inspiration breath-hold

Deep inspiration breath-hold (DIBH) is a method of delivering radiotherapy, whilst limiting radiation exposure to the heart and lungs.

It is used primarily for treating left-sided breast cancer. The technique involves a patient holding their breath during treatment. There are two basic methods of performing DIBH: free-breathing breath-hold, and spirometry-monitored deep inspiration breath hold.

In the DIBH technique, the patient is initially maintained at quiet tidal breathing, followed by a deep inspiration, a deep expiration, a second deep inspiration, and breath-hold. At this point the patient is at approximately 100% vital capacity, and simulation, verification, and treatment take place during this phase of breath-holding.

Patients will have their lung capacity and natural breathing cycle measured so that a comfortable breath-hold capacity can be set. During DIBH, the patient uses a mouth-piece and wears a pair of video goggles which displays their breathing cycle and shows them when they need to inhale and hold their breath.

The DIBH technique provides an advantage to conventional free-breathing treatment by decreasing lung density, reducing normal safety margins, and enabling more accurate treatment. These improvements contribute to the effective exclusion of normal lung tissue from the high-dose region and permit the use of higher treatment doses without increased risks of toxicity.

Treatment of patients with the DIBH technique is feasible in a clinical setting. With this technique, consistent lung inflation levels are achieved in patients, as judged by both spirometry and verification films. Breathing-induced tumor motion is significantly reduced using DIBH compared to free breathing, enabling better target coverage.

There is currently no clear selection criteria to predict which patients will benefit most from the DIBH technique, other than left breast laterality. There is evidence to suggest parasagittal cardiac contact distance is a promising metric for selection and should be assessed in all future DIBH planning studies.

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