US-based medtech company Calidar has completed its first-in-human clinical study evaluating Eidos Prism, a modular add-on device that brings Volumetric X-Ray Diffraction (VXD), also known as 4D Mammography, to existing 3D mammography systems.
Designed to improve breast cancer diagnostics, Calidar’s 4D Mammography system leverages X-ray diffraction to measure molecular-level signals within breast tissue — a capability not available in conventional 3D mammography.
The first-in-human study, conducted in collaboration with Baptist Health Hardin in Elizabethtown, Kentucky, was initiated in August 2025, and enrolled 61 patients. Following completion of the study, clinical investigators submitted two manuscripts for peer review – one detailing the technology’s performance in the first-in-human cohort, and a second covering results of an accompanying reader study. Both manuscripts are currently under review, with publication expected later this year.
Calidar is now preparing for a multi-site pivotal study scheduled to begin in 2027. The company is in discussions with potential clinical sites as it works to expand the evaluation to a broader and more diverse patient population.
The study is expected to involve five to seven sites across four US regions — Northeast, Southeast, Southwest and Northwest — including rural and community health systems, large academic medical centres and independent imaging centres.
“As lead investigator for the first clinical application of Volumetric X-Ray Diffraction, the team at Calidar was a pleasure to work with. They made it easy for me to bridge the needs of my clinical practice with the expectations of our local institutional review board in addressing the potential complexities that can arise with any patient research, ” said Dr. Craig Kamen, principal investigator of the study.
Calidar said its collaboration with Baptist Health provided an opportunity for both teams to learn from each other to inform future studies, including the pivotal trial planned for 2027.
Thomas Blum, VP Clinical, Calidar, said, “Dr. Kamen and the entire team at Baptist Health treated this study as a true collaboration, built upon a shared commitment to providing clearer information to patients earlier in the diagnostic process. This is exactly the kind of partnership we aim to build with each site joining us for the pivotal study.”
Breast cancer diagnostics remain a significant clinical challenge. According to Calidar, approximately 1.8 million breast biopsies are performed each year in the United States, with 70-80% ultimately diagnosed as benign. These unnecessary procedures contribute to more than $7.4 billion in annual healthcare costs and add to the workload of radiologists and pathologists. At the same time, inconclusive imaging results contribute to delayed diagnoses for an estimated 60,000 breast cancer patients annually.
By measuring the structure and composition of tissue — rather than relying solely on its shape or density — Calidar’s 4D Mammography system aims to provide a new dimension of diagnostic clarity.
After completion of the planned pivotal study, Calidar anticipates using the results to support a submission to the US Food and Drug Administration (FDA) for approval of its 4D Mammography system.
The system remains investigational and has not been cleared or approved by the FDA. It is not available for commercial sale and is limited to investigational use in the US under the FDA’s abbreviated IDE requirements.
