Radiology software maker Sirona raises $40M Series D led by Avidity Partners

The round was led by Avidity Partners with 8VC, GreatPoint Ventures, KLT Holdings, Rose Park Advisors and other new and existing investors, bringing total venture funding to about $150M. As of September 30, 2026, Sirona said revenue was up 2.5x year over year and contracted ARR up 2.7x, though it gave no dollar totals. Mean new-customer contracted ARR reached $1.07M and mean total contract value $5.10M, and the company is under contract to onboard more than 1,000 additional radiologists over 12 months. Sirona's RadOS platform combines PACS, reporting, diagnostic viewing, worklist and workflow AI in one cloud system, with an agentic AI layer called Cortex. Proceeds go to client services and US implementation, led by a new hire from Sectra. For founders, Sirona is an example of an AI product replacing a legacy incumbent category rather than adding a feature to it. Seven-figure average contracts and a staffing shortage on the customer side are what let a vertical AI platform justify a platform swap.