射波刀附属加速器非预期电离辐射防护研究OA

Objective To test the unexpected ionizing radiation level of the cyberknife accessory accelerator and provide a reference basis for the protection against unexpected ionizing radiation of the cyberknife accessory accelerator.Methods The assessment points around the cyberknife accessory accelerator and the permanent area of the cyberknife machine room were designed.Under the condition that the cyberknife accessory accelerator provided high voltage without emitting rays,the radiation monitoring detectors were used to measure the ambient dose equivalent rate of each assessment point respectively.The changes and distributions of the ambient dose equivalent rate of the cyberknife accessory accelerator and the permanent area of the cyberknife machine room around the assessment points were analyzed to put forward specific protective suggestions for radiotherapy patients and radiotherapy staff.Results The ambient dose equivalent rate of the assessment points around the cyberknife accessory accelerator was 33.15-86.77 µSv/h,and the unexpected ionizing radiation of the cyberknife accessory accelerator exceeded the standard of general medical electron accelerators by at least five times.The unexpected ionizing radiation of the cyberknife accessory accelerator was mainly concentrated in the middle and bottom of the accelerator,and the ambient dose equivalent rate range of it was 79.10-86.77 µSv/h.The ambient dose equivalent rate of the background of the machine room at the outer opening and midpoint of the labyrinth of the wave knife machine room were comparable,and the maximum did not exceed 0.28 µSv/h.During cyberknife radiotherapy,the unexpected ionizing radiation in the body area of the cyberknife accessory accelerator was the main factor causing additional radiation doses for patients.Conclusion Unexpected ionizing radiation protection against the cyberknife accessory accelerator should be given full attention in radiotherapy clinical practice.For radiotherapy patients,radiation protection should be carried out by reducing the planned treatment time and the patient positioning time under high pressure without reducing the quality of radiotherapy.When necessary,lead shielding protection should be provided for radiation-sensitive organs such as the lens,thyroid gland and sex gland.For radiotherapy staff,machine operation under high pressure should be avoided or reduced,and distance radiation protection measures should be adopted when necessary.