Treat the Untreatable: AiRato’s AI Cuts Radiation Treatment Planning from 6 Hrs to 20 Mins

This article is presented in collaboration with the Startup Support Section, Economic Affairs Bureau, Sendai City Government. The featured startup won the pitch contest at DATERISE! 2025, a global startup event hosted by Sendai City on August 23, 2025. As part of their prize, they will visit Singapore in November 2025 to pursue business development opportunities in the region.

AiRato, a healthtech startup spun out from Tohoku University, is revolutionizing radiation therapy. The company’s flagship product, RatoGuide, is an AI-powered radiation treatment planning support software that slashes the time required to create treatment plans from a typical six hours down to just 20 minutes. In the field of radiation therapy—one of the three major cancer treatment modalities—AiRato is dramatically streamlining the planning process for IMRT (Intensity-Modulated Radiation Therapy), which demands particularly advanced expertise. The company aims to simultaneously advance digital transformation in healthcare and elevate the quality of treatment.

CTO and co-founder Noriyuki Kadoya (right in photo above) is a medical practitioner and researcher who has spent years conducting research in clinical radiation oncology as a lecturer in the Department of Radiation Oncology at Tohoku University Graduate School of Medicine. To bring the technology he had developed in his laboratory over a decade into practical use, he decided to launch the company in March 2022 together with CEO and co-founder Yuto Kimura (left in photo above). Because it was such a niche field, licensing the technology to large corporations proved difficult, and a strong sense of mission—”I have to do this myself”—became the driving force behind the founding.

Three and a half years after founding, in June 2025, AiRato completed the first close of its Pre-Series A funding round, raising 460 million yen (about $3 million US). In August of the same year, the company won the pitch contest at DATERISE! 2025, a global startup event hosted by Sendai City, clearly demonstrating its ambition to challenge the world from Sendai. Currently, the company has completed its medical device approval application for its first-generation product and aims to begin sales in January 2026.

The Niche Market Big Companies Ignored

Behind Kadoya’s decision to found AiRato lay deep expertise in radiation therapy and a strong desire to implement that knowledge in society. As a lecturer at Tohoku University, he worked as a medical practitioner while also running his own research laboratory, where he spent about ten years developing radiation therapy technology. He had been continuously building the foundational technology that now underlies RatoGuide throughout that period.

Initially, he considered licensing to large corporations, but the specialized nature of radiation therapy proved to be a barrier. There were few companies dealing with radiation therapy, and despite searching for partners who could handle the social implementation, none were found. He ultimately concluded that he had to do it himself.

Co-founder and CEO Yuto Kimura was Kadoya’s student in the doctoral program at his laboratory. The two had worked together developing technology in the lab and shared a common vision: to truly implement world-class technology in society and take it global.

Kimura had previously worked as a medical physicist at a regional hospital, where he experienced firsthand how treatment planning quality varied from person to person, and how difficult it was to improve quality when there were no nearby facilities with extensive radiation therapy experience.

He later entered Tohoku University’s doctoral program and began researching AI for radiation therapy. From his clinical experience, he was convinced that the next wave of change would inevitably come. Much of the data handled in radiation therapy consists of images and electronic data, making it highly compatible with AI, which excels at image recognition. He judged that it could work as a viable business.

Treatment Plans That Surpass Human Physicians

AiRato’s product strategy is divided into three phases to be completed by 2032, with planned staged evolution (note: these three phases differ from Phase I, II, and III clinical trials—they represent functional version upgrades of the developed system). Behind this staged approach lies a clear vision.

We’re not aiming for just a workflow improvement tool. We’re aiming to maximize radiation therapy performance by creating plans that surpass human capability, to treat those who couldn’t be treated before. (Kadoya)

What exactly is the radiation treatment planning process? When physicians create treatment plans, they have relied on their experience to determine how and where to apply radiation and where the cancer is located. This treatment planning broadly consists of three processes:

1. Tumor delineation work
2. determining the irradiation field—deciding from where to deliver approximately 100 radiation beam shots
3. Verifying that the planned treatment can be accurately delivered to the patient. AiRato aims to realize treatment plans that “surpass human capability” by progressively implementing AI across all three processes.

The first-generation entry model is nearly complete after about three years from founding and may begin sales early in 2026. In this first generation, AI automatically generates treatment plans at the level typically performed by experienced physicians.

In the second generation, AI will autonomously optimize these processes. Why some patients actually don’t respond to treatment, or conversely why they do, hasn’t been sufficiently clarified in current practice. So after analyzing the results from launching the first generation, they’ll take an approach of independently building up to a level that surpasses human capability from the second generation onward. The company is currently developing the second generation in parallel.

The biggest difference from competing products is that we’ve implemented AI across all three major processes of treatment planning. (Kadoya)

Let’s examine these three major processes.

First, the automatic organ contouring (segmentation) function. For approximately 200 CT images, AI automatically outlines normal tissues such as the liver and lungs. Normally, this requires manually drawing on each image at the millimeter level, like using painting software, but AI automates this work. Compared to other companies’ products, AiRato has developed coverage for almost all organs.

The second function is called Good Plan—automation of irradiation design. Based on data considered to have truly high therapeutic efficacy, AI appropriately determines the irradiation design of where to apply radiation. While many products allow facilities to input their own data for workflow improvement, AiRato has built a higher-concept software that enables any facility to create high-quality plans.

Third is the safety verification function. Normally, radiation technologists spend about an hour measuring whether radiation will actually be delivered as planned using detectors. They’ve developed an AI that, based on past data, determines whether a plan can be safely implemented. Other companies haven’t reached this point yet, so the company’s strength lies in having fully automated all three main processes of treatment planning to the point where everything can be done automatically.

This comprehensive approach delivers significant impact to clinical practice. For IMRT treatment, treatment planning that normally takes six hours is reduced to about 20 minutes, with support for a wide range of applications including head and neck cancer, prostate cancer, lung cancer, and cervical cancer. This is highly valued for addressing variations in treatment outcomes based on physician experience and solving medical staff shortages.

Finding “True Partners” for Sales Expansion

AiRato’s market strategy is to first build solid results domestically, then use that as leverage for overseas expansion. Currently, there are approximately 900 radiation therapy facilities in Japan, and the company is advancing market development through direct sales leveraging its own network. For facilities beyond the reach of direct sales, they’re also considering expansion through a distributor system.

Because it’s such a specialized product, if we just ask distributors to knock on doors and then we still have to go explain ourselves, the effort would be no different from direct sales. With each company that could become a distributor, we’re at the stage of exploring whether we can create additional synergies—truly valuable partnerships. (Katodani)

There are two product lineups. The flagship RatoGuide requires medical device certification and is currently under PMDA application. Meanwhile, RatoCheck, which was released earlier, doesn’t require certification and has already been introduced to the market, with about four units deployed at large medical institutions including university hospitals and cancer centers.

RatoCheck has a checking function where, after a medical institution manually creates a treatment plan as usual, the AI evaluates that plan and shows “what AI would plan.” However, due to its nature as a non-medical device, there are limitations. Even if AI indicates “this is a better plan,” that plan cannot actually be adopted for treatment—it remains only as reference information for comparison.

Asian and North American Expansion

In July 2025, AiRato signed an exclusive overseas distributor agreement with Sumitomo Corporation, establishing a framework for full-scale expansion into the Asian market. Sumitomo Corporation’s Life Science Business Sector has been engaged in pharmaceutical-related business since the 1970s, providing support for drug discovery research and development for pharmaceutical companies, supplying raw materials, and offering services such as sales, marketing, and contract manufacturing.

This partnership is part of a strategy to make medical technology support services for medical institutions a new pillar. Following its investment in AOI Biosciences, a Japanese startup conducting infertility and recurrent pregnancy loss testing, this is Sumitomo’s second project combining the advanced technology of Japanese medical startups with its global network to expand medical support business worldwide.

The regulatory strategy is also clear. Japan’s PMDA (Pharmaceuticals and Medical Devices Agency) and U.S. FDA (Food and Drug Administration) are the strictest regulatory authorities, and they anticipate that obtaining approval from these two will likely enable approval in most other countries. They recognize that obtaining Japanese and U.S. approvals is key to expansion in other countries for global deployment.

While accelerating global expansion, AiRato is also working to strengthen its organizational structure. For rapidly growing startups, talent acquisition is always one of the most critical issues.

Because the main product, a medical device, hasn’t yet obtained regulatory approval, they’re not conducting sales activities. Therefore, the talent most needed at this stage is in development, especially AI engineers. While the company has hired various personnel, they still don’t have enough and are constantly searching.

Another challenge is CxO-level talent who can oversee sales strategy. Currently, Kadoya himself is conceiving the sales strategy, but they’re looking for someone with strong global expansion experience who can formulate clear strategies.

In the June 2025 Pre-Series A funding round, Nissay Capital led the investment, with Sumitomo Corporation and 77 Capital joining as new investors, while existing investors mint, Central Japan Seed Fund, and GxPartners LLP continued their support. They plan to use these funds to strengthen their organizational structure.

The company is currently recruiting members to co-create their business and services—including development engineers (AI, UI), technical sales, and board members—to realize their mission of “saving all cancer patients through radiation therapy.” They’re recruiting both full-time employees and contractors and are seeking talent with a global perspective.

The Right Approach for Deep Tech

On August 23, 2025, “DATERISE! 2025,” the first large-scale global startup event hosted by Sendai City, was held. Under the theme “SENDAI to Global!”, the event featured diverse programs supporting startups, student entrepreneurs, and future challengers aiming to take flight from Sendai and Tohoku to the world.

As the main program, a pitch contest was held for startups targeting overseas expansion, with 11 companies selected from numerous applicants presenting their business content and passion for their challenges. The winner was offered a support program in Singapore, providing opportunities for overseas expansion.

The judges told us that while many other deep tech startups have technology but it’s unclear what to use it for, our product is clear, and there’s a strong sense that we can win globally. (Kadoya)

In fierce competition, AiRato emerged victorious. The judging evaluated the social impact of reducing the burden on medical sites and improving treatment access through automation and advancement of radiation treatment planning. Additionally, they recognized the continuous improvement of AI algorithms based on clinical data and operational know-how in medical settings, as well as contributions to medical challenges in markets including Asia and strategic policies toward commercialization.

Behind this evaluation lies the fact that AiRato managed to avoid the “deep tech pitfall.” Many deep tech startups have excellent technology but struggle with unclear specific applications. However, AiRato had a clear application from the university research stage. Even during development, it was clear what it would be used for.

We can’t beat U.S. in AI technology itself. That’s precisely why we focused on the specific field of radiation therapy from the start, developed specialized AI tailored to it, and built it in a state where it could be loaded onto that application. (Kadoya)

This clear direction has become AiRato’s major strength. By winning DATERISE!, the company secured a three-day overseas expansion support program in Singapore. They plan to visit Singapore in November, visit hospitals through the network of partner Sumitomo Corporation, and meet with Asian medical device manufacturers and venture capitalists.

I’m confident that I’m the strongest in Japan for going global in this field. I’ve given invited lectures together with researchers from Stanford and Harvard on the global academic stage. (Kadoya)

In the highly specialized field of radiation therapy, Kadoya’s academic achievements and network serve as the greatest weapon for competing in the global market.

As Citizens, Not Patients

In Japan, approximately one million people are diagnosed with cancer each year, and that number continues to grow. As working lifespans extend, the proportion of patients continuing treatment while working is also increasing, driving demand for radiation therapy, which enables minimally invasive cancer treatment.

Under the mission of “saving all cancer patients through radiation therapy,” AiRato is tackling this social issue head-on. The company’s vision is “a world where we cure as many cancers as possible, allowing people to live as citizens rather than patients.”

Our ultimate goal is to treat those who couldn’t be treated. The first generation still has strong aspects of workflow improvement, but from the second generation onward, we’ll create treatment plans that truly surpass human capability and enable treatment of patients who couldn’t be cured before. We want to realize that with machines. (Kadoya)

Regarding Japan’s position in the medical AI market, Kadoya is optimistic. He believes there’s great potential in AI utilization in healthcare. From his experience working overseas, he notes that while challenges exist everywhere, there are also challenges that only Japanese people have noticed. His view is that there’s still plenty of room for development there.

AiRato is currently conducting multiple collaborative research projects with major medical institutions nationwide, including Hokkaido University Hospital, Tohoku Medical and Pharmaceutical University Hospital, Fujieda Municipal General Hospital, and Kumamoto University. Through these studies, they’re advancing support for a wide range of cancer types including head and neck cancer, prostate cancer, lung cancer, esophageal cancer, and brain tumors.

Particularly noteworthy is that they’re conducting multi-center collaborative trials at nine medical institutions of varying scales and characteristics, quantitatively evaluating implementation effects such as operational efficiency, burden reduction, and increased medical reimbursements. This scientific approach provides a foundation for enhancing reliability as a medical device and accelerating adoption.

Domestic sales beginning in January 2026, full-scale expansion into the Asian market from 2026 onward, and FDA approval and North American market expansion in the early 2030s—AiRato’s roadmap is clear. The strategic partnership with Sumitomo Corporation will drive Asian expansion in earnest. Thorough preparations for FDA approval are also underway, with the second-generation product already being developed with coding compliant with FDA standards.

The technology that Kadoya and Kimura cultivated over ten years in their laboratory is now entering the final stage of practical application as a weapon to save cancer patients worldwide. A world where cancer patients can live as “citizens” rather than “patients”—AiRato’s challenge toward realizing that vision has only just begun.

Deeply specializing in the specific field of radiation therapy while keeping an eye on the global market—this strategy is AiRato’s strength. Rather than competing on AI technology itself, they focused on radiation therapy from the start and developed specialized AI tailored to it. Through this clear differentiation strategy, they maintain advantages even against U.S. competitors.

AiRato’s challenge as a global healthtech startup will serve as an important litmus test showing that Japanese medical technology can compete globally. The trajectory of technology born in a Tohoku University laboratory spreading from the local base of Sendai to Asia and then the world holds the potential to become a model case for global expansion by regional startups.