Imagine being told that a tumor has been found on your lung or breast and that you will require radiation therapy. While it’s devastating news, the best thing you can do to limit your radiation exposure to other organs is, quite simply, take a deep breath.
Deep Inspiratory Breath Hold (DIBH) is a technique employed in radiation therapy when a patient is instructed to take a deep breath and hold it while receiving treatment. By utilizing DIBH, radiation oncologists enhance the accuracy of treatment delivery, reduce radiation exposure to healthy tissue and improve patient outcomes.
“During the time of radiation simulation, which is when we scan patients in order to plan their radiation treatment, we ask them to take a moderate breath and hold it,” said Dr. Jean-Pierre Obeid, a radiation oncologist with Cleveland Clinic Indian River Hospital. “We also have them hold their breath at the time of treatment while they are on the table. The purpose of this exercise is to help inflate the lungs to change the physiology of the patient in such a way to improve normal tissue sparing, reduce the dose of radiation, and to improve the accuracy and reproducibility of the target treatment.
“We shoot for a minimum breath hold of 20 seconds, although some patients can hold their breath longer,” Dr. Obeid continued. “This inflates lungs so that whenever we radiate a certain volume, there’s less density of lung tissue, which in turn reduces the dose to the whole lung in general. The breath hold pushes the heart backwards and down out of the field for breast and other lung tumors, giving us the ability to measure precisely and target the treatment more accurately. Not only does it reduce the dose that goes to normal structures like the lung and heart, but it also benefits us by being more precise and having to treat less of a volume since we don’t have to cover a larger area. Smaller tumors that sometimes get smeared out when we image a patient who is breathing normally, are more easily detected.”
DIBH is used for early-stage lung cancer and left-sided breast cancers.
In lung cancer treatment, DIBH causes the lungs to expand, creating a better separation between the target tumor and critical structures such as the heart and healthy lung tissues.
This increased separation reduces the chance of radiation-induced damage to healthy tissues and reduces the risk of long-term lung damage.
Lung tumors can move during breathing due to respiratory motion. By utilizing DIBH, tumor motion is reduced, leading to increased accuracy in target localization and minimizing the need for larger target margins. This reduction in tumor motion helps to spare nearby organs like the heart and esophagus, and reduces potential complications.
“With this technique we can catch lung tumors that wouldn’t even show on a simulation CT scan,” Dr. Obeid implored. “Without DIBH, the tumor would be smeared to oblivion or simply present as a haziness. The breath hold allows for a better snapshot, identifying the tumor and allowing us to treat the cancer earlier.”
For left-sided breast cancer patients, the proximity of the heart to the treatment area presents a challenge in radiation therapy. DIBH allows for greater separation between breast tissue and the heart by expanding the lungs and pushing the heart away from the radiation field. This reduces the radiation dose to the heart, minimizing the risk of cardiovascular complications.
The use of DIBH in breast cancer patients also spares healthy lung tissue from unnecessary radiation exposure by pushing the breast tissue away from the lungs and lowering the risk of long-term lung damage. The physician can better define target volume and treatment fields, ensuring that the radiation is delivered precisely to the intended area while sparing nearby normal tissue.
“DIBH is typically not utilized for right-sided breast cancer patients because the heart is positioned farther away and the radiation is already so accurate that it’s not necessary,” said Dr. Obeid. “If a patient presents with bilateral breast cancer, then we would treat both sides with DIBH.”
When asked what happens if a patient can’t hold their breath for the specified amount of time, Dr. Obeid said that they treat across the respiratory breath cycle with continuous inhalation and exhalation as the lungs inflate and deflate. Respiratory gating is a process that uses advanced computer software to guide the delivery of the radiation as the patient breathes. “Instead of treating in just one breath hold, we treat in in four or five accounting for subtle changes that can occur over the course of seconds.
“The key concept behind the entire process is reproducibility,” he continued. “I need to be sure that I’m treating the same region and space so the breaths need to be similar. We track this using surface imaging. Sometimes it’s a challenge to make sure that the patient is getting into the threshold correctly.
“The main thing that is impacted by DIBH is decreased toxicity and not long-term survival rates. Even though the chance of curing cancer is about the same whether we use DIBH or not, the amount of future heart and lung disease is decreased. It really is amazing that with the right technology to read the scans, something as simple as holding your breath can make such a dramatic difference.”
Dr. Obeid received his medical degree at the University of Miami Miller School of Medicine in Miami, Florida; completed his internship in internal medicine at Beth Israel Deaconess Medical Center in Boston; and served his residency in radiation oncology at Stanford Health Care in Stanford, California. His office is located in the Scully-Welsh Cancer Center at Cleveland Clinic Indian River Hospital, 3555 10th Court, Vero Beach. You can call 772-794-3333 to schedule an appointment.
