Dr. Zimmerman was performing medical X-ray services in the days when Woodrow Wilson was in the White House, when Congress was preparing to enact Prohibition, and before commercial radio broadcasting became a reality.

As increasing numbers of patients came to Dr. Zimmerman, additional radiologists joined him. The group quickly became recognized as the Sacramento Valley’s preeminent radiology practice.

Over the years, RAS has introduced a succession of pioneering diagnostic and therapeutic radiology techniques. For example, RAS installed the first million-volt therapeutic X-ray machine west of the Mississippi in 1947. In the early 1980s we bought the first CT body scanner to Sacramento and established the first intraoperative radiation therapy program in the western United States. As technology advanced in the 1990s, RAS introduced many new procedures to the area, including image-guided breast biopsies, which eliminated the need for a surgical procedure; gamma knife radiosurgery; and positron emission tomography (PET).

RAS continued to forge new ground as the new millennium approached, with prostate seed implants, intensity-modulated radiation therapy (IMRT) for cancer treatment, breast MRI and computer-aided detection on all mammograms.

Today RAS maintains that pioneering spirit with PET/CT fusion, image-guided radiotherapy (IGRT) and outpatient interventional radiology procedures including venous ablation, uterine artery embolization and vertebroplasty.