B dot Medical: Successful Proof of Concept for Ultra-compact Proton Therapy System

Proof of feasibility of downsizing to the world's smallest size, and moved to final confirmation for application for PMDA approval

The ultra-compact proton therapy system used in the POC (Photo: Business Wire)

TOKYO--()--B dot Medical Inc. and Research Center for Nuclear Physics, Osaka University (RCNP) have conducted a Proof of Concept (POC) of the ultra-compact proton therapy system under development and confirmed that the proton beam generated by an accelerator was bent inside the superconducting bending magnet in the system and irradiated to the isocenter (*1). That proves the feasibility of the development concept of downsizing the device and is a major step forward in improving access to cancer treatment with fewer side effects.

This POC was conducted as part of the International Joint Usage/Research Center program promoted by the Research Center for Nuclear Physics (RCNP) at Osaka University and is also the first experimental research using the upgraded AVF cyclotron beam at the Accelerator Facility of the RCNP. In the POC, the proton beam generated by the accelerator was passed through a superconducting bending magnet (*2) developed in-house, and it was confirmed that the proton beam was irradiated to the isocenter by being bent to an arbitrary angle in the bending magnet.


The Isocenter is the intersection of each mechanical rotation axis.


In radiation therapy, it refers to the area where the radiation is most concentrated.


(by “Guidelines of Physical and Technological Quality Assurance for Particle Beam Therapy”)




Press release, June 25, 2021


B dot Medical Successfully Develops Compact Bending Magnet for Proton Beam Using Superconducting Technology”



About B dot Medical

B dot Medical Inc. is a start-up that originated at the National Institute of Radiological Sciences (NIRS) and is developing an ultra-compact proton therapy system by utilizing the advanced technology and experience cultivated at NIRS. We are challenging the world with Japanese technological innovation power.
By using a technology that bends the proton beam to an arbitrary angle, which is completely different from the conventional system structure, the system can be made as compact and affordable as X-ray therapy systems. We aim to improve access to proton therapy by making it possible to install proton therapy in hospitals where it has been difficult due to space and cost constraints.

About RCNP

The Center is an International Joint Usage/Research Center with accelerator facilities consisting of an AVF cyclotron and a ring cyclotron. It is the largest accelerator facility in Japan among university-affiliated accelerator facilities, and it promotes cutting-edge research in nuclear physics and its applications while taking advantage of its unique characteristics. In addition to providing a unique place for research and education within Osaka University, the center promotes experimental and theoretical research in fundamental physics through collaboration with researchers not only in Japan but also around the world as an International Joint Usage/Research Center for subatomic science.

Company Information



B dot Medical Inc.


5-10-10 Harue-cho, Edogawa-ku, Tokyo 134-0003 JAPAN


Takuji Furukawa, President and CEO


March 1, 2017

Business activity:

1) Consulting support of particle therapy


2) Developing proton therapy systems

Web site:




Name: Miyuki Takei
Department: Corporate Planning Office
TEL: +81-3-6808-8731
Email: info@bdotmed.co.jp

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Name: Miyuki Takei
Department: Corporate Planning Office
TEL: +81-3-6808-8731
Email: info@bdotmed.co.jp