AI-powered radiation therapy startup AiRato raises 170 million yen from Mitsui Sumitomo Insurance Venture Capital and SMBC Venture Capital.

AiRato Inc. (Headquarters: Sendai, Miyagi; Co-CEOs: Yuri Kimura and Tomoyuki Kakutani), which develops and commercializes AI-powered radiation therapy planning support services, announced that it has raised 170 million yen in the 2nd close of its Pre-Series A round.

New investors participating in this round include Mitsui Sumitomo Insurance Venture Capital Co., Ltd. and SMBC Venture Capital Co., Ltd.

With this latest funding, AiRato’s total amount raised in the Pre-Series A round (1st and 2nd closes combined) has reached 630 million yen, bringing the company’s total funding since its founding to 750 million yen.

Overview of the Funding

Amount raised in this round: 170 million yen

• New investors (in no particular order): Mitsui Sumitomo Insurance Venture Capital Co., Ltd., SMBC Venture Capital Co., Ltd.

Background and Purpose of the Funding

Currently, it is said that one in two people will develop cancer in their lifetime, and the number of cancer patients is expected to double over the next 20 years.

Among the three major cancer treatment methods, radiation therapy places the least physical burden on patients and is becoming increasingly important as a cancer treatment option in an aging society.

In recent years, Intensity-Modulated Radiation Therapy (IMRT)※1—one of the most advanced forms of radiation therapy—has become widely adopted and has demonstrated high therapeutic effectiveness. However, despite its advantages, IMRT faces challenges such as variability in treatment quality depending on clinician experience, and a shortage of qualified medical professionals (leading to excessive workloads). As a result, IMRT is not yet being administered to as many patients as anticipated.

To address these challenges, AiRato is developing and commercializing AI software for radiation therapy planning, aiming to become a globally competitive Japanese medical device manufacturer.

The funds raised in this round will be used to accelerate the R&D and clinical implementation of “RatoGuide,” AiRato’s AI-based radiation therapy planning support system, as well as to prepare for international expansion (particularly in Asia), expand collaborative research with medical institutions, and strengthen recruitment and organizational structure.

※1 Intensity-Modulated Radiation Therapy (IMRT): A radiation therapy technique that adjusts the intensity of radiation beams from multiple directions to deliver a precise dose distribution.

Comments

Taro Nishijima, Manager, Investment Division, Mitsui Sumitomo Insurance Venture Capital Co., Ltd.

The AI radiation therapy support system developed by AiRato Inc. is an indispensable solution for promoting the wider adoption of Intensity-Modulated Radiation Therapy (IMRT), a highly effective form of cancer treatment. This technology has the potential to significantly improve treatment outcomes and enhance patients’ quality of life.

AiRato is a Tohoku University–origin startup led by Dr. Tomoyuki Kakutani, a global leader in radiation therapy AI research. The company possesses both strong technological expertise and business development capabilities, giving it the potential to expand globally as a Japan-born AI medical device startup.

We are confident that AiRato will achieve regulatory approval in Japan at an early stage and deliver its AI radiation therapy support solutions to numerous patients and medical institutions. As part of an insurance and financial group, we will leverage our full range of resources to help realize AiRato’s vision.

Yuta Watanabe, Deputy General Manager, Investment Business Division I, SMBC Venture Capital Co., Ltd.

We are honored to have the opportunity to invest in AiRato Inc.

The dedicated and talented team led by Co-CEOs Kimura and Kakutani is pursuing a mission that goes beyond simple operational efficiency. Their work contributes meaningfully to expanding treatment options for patients and ultimately to making safe and effective radiation therapy more widely accessible, thereby saving more lives.

As a member of the SMBC Group, we are committed to supporting this remarkable and impactful challenge in every way we can.

About Our Business

As Japan’s first radiation therapy AI startup, AiRato is developing AI-powered software to support radiation therapy planning. By introducing AI into the planning process for Intensity-Modulated Radiation Therapy (IMRT), we have achieved results showing that treatment planning time can be reduced from the conventional six hours to approximately 20 minutes.

Our technology covers a wide range of cancer types — including head and neck, prostate, lung, and cervical cancers — and features both automatic contouring and automatic treatment planning capabilities.