A Medical Device Daily

Lung tumors have been difficult to treat with radiation therapy because patient breathing causes tumors to move around. This uncertainty about the tumor’s exact position has made it challenging to target the tumor with radiation beams while simultaneously avoiding normal tissues with these same treatment beams.

The National Institutes of Health (NIH) has funded a study by William Beaumont Hospital (WBH, Royal Oak, Michigan) investigators to examine how lung tumors move and to refine ways to compensate for breathing-induced tumor motion.

WBH researchers, led by clinical physicist Geoffrey Hugo, PhD, are using two Elekta (Stockholm, Sweden) technologies — Elekta Synergy, a cancer treatment delivery system with intensity modulated radiation therapy (IMRT) and image-guided radiation treatment (IGRT) system using a patient breathing control device (Elekta Active Breathing Coordinator) — to conduct the study.

“This study attempts to measure lung tumor movement in patients with different stages of non-small cell lung cancer and also tumor motion in the same patients during their treatment course,” said Hugo.

He continued: “The ultimate goals are to better target lung tumors and allow use of smaller treatment margins based on how each patient’s tumor moves during the breathing cycle and even adapt the patient’s treatment throughout the treatment course.”

Strategies that improve the ability to target cancer and avoid normal tissues also enable clinicians to employ more aggressive treatments, such as using higher doses over fewer treatment sessions, he adds. Both Elekta’s IMRT and IGRT system, Elekta Synergy, and Elekta’s Active Breathing Coordinator have been used individually to improve the effectiveness of radiation therapy through better targeting, the company said.

The WBH study presents an opportunity to combine both technologies to improve lung cancer treatments, Elekta said.

Elekta Synergy is a multifunctional linear accelerator equipped with imaging equipment that enables doctors to acquire images of the patient with the patient in the treatment position. Clinicians can then use the imaging data to fine-tune the patient’s position immediately prior to treatment. Elekta’s Active Breathing Coordinator is designed to help patients suspend their breathing at a precise point, thereby freezing the target’s motion to facilitate radiation therapy.

In the William Beaumont study, Elekta’s Active Breathing Coordinator will be used to measure respiratory-induced tumor motion and what sort of breath hold (i.e., shallow, deep, on exhalation, on inhalation) will result in the least variability in tumor position.