Before starting treatment using an accelerator-based boron neutron capture therapy (BNCT) system, acceptance tests by medical device manufacturers and commissions by medical staff are performed at medical institutions. In addition to the action items common to radiotherapy systems, there are items that should be considered specifically for an accelerator-based BNCT system. Since the accelerator-based BNCT system generates high-intensity neutrons, the safety of the system and the performance of the neutron beam are confirmed in the acceptance test. Data necessary for clinical practice are mainly acquired in commissioning. In this chapter, in addition to the dosimeters and phantoms used in the BNCT irradiation field, the acceptance test and commissioning required at the medical institution with the accelerator BNCT system are presented.