Early in his career, Dr. Timmerman specialized in treating brain tumors and other cranial abnormalities with devices like the Gamma Knife, an extremely precise, noninvasive radiosurgical tool that employs multiple angles to deliver gamma radiation. He was intrigued by the idea of moving this sort of multidirectional, precise treatment to other areas of the body. But there was a major hurdle: tumors inside the head don’t move because the skull is immobilized with a frame during Gamma Knife treatment. By contrast, tumors in the body can move a great deal due to activities like breathing and movement of waste through the intestines. But with more sophisticated image guidance and tracking, Dr. Timmerman and a few others began developing a method (known as SAbR or SBRT) by which it was possible to account for movement and still safely deliver this treatment. Dr. Timmerman became known for his leadership in developing clinical trials to show how well SAbR worked in different parts of the body.

One of Dr. Timmerman’s greatest successes was the development of a trial that demonstrated inoperable lung cancer patients treated with SAbR could have considerably higher tumor control than with conventional radiation while still mostly avoiding toxicity. This provided hope to a whole new class of patients – the elderly, those with multiple health conditions, and others – who previously faced poor odds of beating their cancer. His treatment method has now become the new standard of care for this class of patients.