Yes, boron can be used to protect the walls of a treatment room against neutrons. Boron is a chemical element that has the ability to absorb neutrons, which makes it useful as a radiation shielding material. Boron is commonly used in the form of borated polyethylene, which is a type of plastic that contains boron atoms. This material is used to shield rooms and equipment in nuclear facilities, as well as in medical facilities for radiation therapy. The effectiveness of boron as a shielding material depends on the density and thickness of the borated material used. If you have any questions, you let me know in the comment box..