The Radiation Oncology service at the Flint Animal Cancer Center is known for breaking new ground. They were the first veterinary oncology service in the U.S. to employ a linear accelerator to treat companion animals and the first in the world to offer stereotactic radiation therapy for pets.

Under the direction of Dr. Del Leary, medical physicist, they are at it again. Over the last year, Leary has worked with radiation oncologists to develop 3-D-printed molds, known as boluses, that contour to patient bodies to improve radiation dose delivery to tumors. According to Leary, this novel approach currently is used in 10-20 percent of human radiation oncology services worldwide.

Until recently, the Flint Animal Cancer Center used conventional bolus sheets made of a gel-like substance. However, the sheets are limited in their ability to contour over irregular surfaces leaving air gaps that reduce the functionality of the bolus.

Traditional Bolus 3-D Printed Bolus
Patient with traditional bolus                                                                                                                                Patient with personalized 3-D printed bolus

To create a custom bolus, Leary uses the patient’s CT image and sends the data to the 3-D printer. The CT image provides a blueprint to create a unique mold that hugs curves and crevices.

“Using custom 3-D printed molds, we’ve found there’s a better agreement between what we have in the planning system and the dose delivered to the patient,” said Leary. “The molds minimize the air gaps so  we can increase the dose to the tumor.”

Putting the new technology to the test, radiation oncologist Dr. Tiffany Martin found significant improvement to tumor coverage when using the custom mold compared to traditional bolus for head and neck cases. She has submitted her findings for publication.

“While this is a novel approach today,” said Leary, “I think this quickly will become mainstream in both human and veterinary practice.”