A 13-person, Dartmouth-born medical device company using supine MRI and 3D printing to give breast surgeons something they have never had: a precise, patient-specific map of the tumor before the first incision.
In breast conserving surgery, the hardest part is invisible - knowing exactly where a tumor begins and ends. CairnSurgical builds a physical answer.
Eight years before it had an FDA filing, CairnSurgical was an idea in an operating room at Dartmouth-Hitchcock Medical Center. A cancer surgeon, Dr. Richard Barth, and colleagues at the Thayer School of Engineering kept circling the same problem: when a surgeon performs a lumpectomy, the tumor is buried in soft tissue, and the tools for finding it - a thin wire, or a small implanted seed - point to a single spot. They say almost nothing about the tumor's true size, shape, depth, or edges.
That gap has a cost. Roughly one in five breast conserving surgeries fails to remove all of the cancer at the margins, sending the patient back for a second operation. CairnSurgical's founders decided the surgeon should have a map, not a dot.
The result is the Breast Cancer Locator, or BCL, System. It starts with a supine MRI - the patient scanned lying face-up, in the same position she will be on the operating table. From that scan, the company generates an interactive 3D model of the tumor and 3D-prints a plastic, bra-like form molded to that one patient's anatomy. Placed on the breast in the operating room, the form lets the surgeon bracket the entire tumor volume with markers, guided by a precise blueprint rather than a guess.
Spun out of Dartmouth College and Dartmouth-Hitchcock in 2015, the company operates out of an office park in Lebanon, New Hampshire, with about 13 employees. Its logo is a cairn - the stack of stones hikers use to mark a trail so the next person does not get lost. It is an unusually honest description of the product.
The re-excision problem is why CairnSurgical exists. The pitch is not to replace the surgeon - it is to remove the guesswork.
The workflow is built to match the reality of the OR - imaging the patient in the exact position she will be on the table.
The patient is scanned lying face-up so the model matches operating-table position.
The Visualizer builds an interactive 3D image showing tumor size, shape, depth and a 1cm margin.
A patient-specific, bra-like plastic form is 3D-printed to that individual's anatomy.
In the OR, the surgeon uses the form and Visualizer to bracket and remove the full tumor volume.
CairnSurgical sells a single-use, patient-specific hardware guide paired with visualization software.
A patient-specific, 3D-printed, bra-like plastic form molded to each patient's breast. It lets a surgeon place markers that bracket the entire tumor volume, offering volume-based guidance rather than a single point - and eliminating the need for painful wire or seed localization.
An interactive, web-based 3D model of the tumor derived from supine MRI. It displays tumor dimensions, distance from chest wall and skin, and a 1cm margin boundary - serving as both a planning tool before surgery and a reference during it.
By giving breast cancer surgeons detailed and critical information that they don't have today, we intend to transform the surgical experience.
CairnSurgical is a B2B medical device manufacturer. Its customers are breast surgeons and surgical oncologists, and the hospitals and cancer centers where they operate. Because each BCL guide is printed for one patient and used once, the model is fundamentally per-procedure - a manufacturing business as much as a software one. Clinical study sites have included Women & Infants Hospital in Rhode Island, Moffitt Cancer Center, and St. Peter's Health Partners in Albany, New York.
The competitive field is tumor localization. Traditional wire-guided localization and wireless markers - radioactive seeds, SAVI SCOUT radar reflectors, Endomag's Magseed, and RFID tags - all share one limitation: they mark a point. CairnSurgical's differentiator is volumetric, patient-specific, 3D guidance derived from the patient's own imaging. Whether that advantage justifies the added MRI-and-printing workflow is exactly what its clinical trials are meant to answer.
Commercialization is gated on regulation. The company pursued a limited launch in select European markets while running its US pivotal trial, and in 2026 filed an FDA De Novo 510(k) submission - the pathway for a genuinely novel device without an existing equivalent. It is the slow, unglamorous arc of real medical technology: eleven years from founding to an FDA request.
Includes a $4.5M Series A2 (2024) led by Morningside Ventures, an earlier Morningside-led round (2019), and non-dilutive support from the National Cancer Institute, the New Hampshire Innovation Research Center, and the NIH-funded DRIVEN Accelerator Hub - where CairnSurgical was the first participant company.
Co-founded by Dr. Richard Barth (surgery), Venkat Krishnaswamy, PhD, and Keith Paulsen, PhD (engineering) out of Dartmouth. David "Dave" Danielsen serves as Chief Executive Officer, leading the company through its pivotal trial and commercialization.
Founded as a spinout of Dartmouth College and Dartmouth-Hitchcock Medical Center, built on Dr. Barth's image-guided surgery concept.
Morningside Group leads an investment; CairnSurgical becomes the first company in the NIH-funded DRIVEN Accelerator Hub.
The Breast Cancer Locator System is named the NH Tech Alliance's Product of the Year.
An early 14-patient pilot study achieves 100% negative margins.
Closes financing led by Morningside Ventures to fund the US pivotal trial and a limited European launch.
A European multi-institutional study reports 94% margin-negative resections in Annals of Surgical Oncology.
Completes US pivotal trial enrollment and files an FDA De Novo 510(k) submission for the BCL System.
CEO David Danielsen presents the patient-specific Breast Cancer Locator at LSI Europe '24.
The Breast Cancer Locator (BCL) System - a patient-specific, 3D-printed surgical guide plus an interactive 3D Visualizer that help surgeons precisely locate and remove breast tumors during lumpectomy.
In breast conserving surgery, roughly 20 to 25 percent of operations fail to remove all cancer at the margins, requiring a second surgery. CairnSurgical aims to reduce that re-excision rate and remove less healthy tissue.
Traditional wire and seed methods mark a single point and say little about tumor size, shape, or edges. CairnSurgical provides a full 3D map of the tumor volume derived from supine MRI.
As of 2026 the company filed an FDA De Novo 510(k) submission and completed US pivotal trial enrollment, and pursued a limited commercial launch in select European markets. US clearance was pending.
It is based in Lebanon, New Hampshire, was spun out of Dartmouth, and is led by CEO David (Dave) Danielsen. Co-founders include Dr. Richard Barth, Venkat Krishnaswamy, and Keith Paulsen.