Department of Radiology, Aichi Medical University Hospital, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195 Japan.
Department of Radiation Oncology, Aichi Cancer Center, 1-1 Kanokoden, Chikusa-Ku, Nagoya, Aichi, 464-8681 Japan.
J Radiat Res. 2020 May 22;61(3):419-425. doi: 10.1093/jrr/rraa016.
Direct irradiation may cause malfunctioning of cardiac implantable electronic devices (CIEDs). Therefore, a treatment plan that does not involve direct irradiation of CIEDs should be formulated. However, CIEDs may be directly exposed to radiation because of the sudden intrafractional movement of the patient. The probability of CIED malfunction reportedly depends on the dose rate; however, reports are only limited to dose rates ≤8 Gy/min. The purpose of this study was to investigate the effect of X-ray dose rates >8 Gy/min on CIED function. Four CIEDs were placed at the center of the radiation field and irradiated using 6 MV X-ray with flattening filter free (6 MV FFF) and 10 MV X-ray with flattening filter free (10 MV FFF). The dose rate was 4-14 Gy/min for the 6 MV FFF and 4-24 Gy/min for 10 MV FFF beams. CIED operation was evaluated with an electrocardiogram during each irradiation. Three CIEDs malfunctioned in the 6 MV FFF condition, and all four CIEDs malfunctioned in the 10 MV FFF condition, when the dose rate was >8 Gy/min. Pacing inhibition was the malfunction observed in all four CIEDs. Malfunction occurred simultaneously along with irradiation and simultaneously returned to normal function on stopping the irradiation. An X-ray dose rate >8 Gy/min caused a temporary malfunction due to interference. Therefore, clinicians should be aware of the risk of malfunction and manage patient movement when an X-ray dose rate >8 Gy/min is used for patients with CIEDs.
直接照射可能导致心脏植入式电子设备（CIED）发生故障。因此，应制定不涉及直接照射 CIED 的治疗计划。然而，由于患者在分次内的突然移动，CIED 可能会直接暴露于辐射下。据报道，CIED 发生故障的概率取决于剂量率，但报告仅局限于剂量率≤8 Gy/min。本研究旨在探讨剂量率>8 Gy/min 的 X 射线对 CIED 功能的影响。将四个 CIED 放置在辐射场的中心，并用不带平坦化滤波器的 6 MV X 射线（6 MV FFF）和不带平坦化滤波器的 10 MV X 射线（10 MV FFF）进行照射。6 MV FFF 的剂量率为 4-14 Gy/min，10 MV FFF 的剂量率为 4-24 Gy/min。在每次照射过程中，使用心电图评估 CIED 运行情况。在 6 MV FFF 条件下，当剂量率>8 Gy/min 时，三个 CIED 发生故障，而在 10 MV FFF 条件下，四个 CIED 全部发生故障。所有四个 CIED 均观察到起搏抑制的故障。故障与照射同时发生，停止照射后同时恢复正常功能。X 射线剂量率>8 Gy/min 会因干扰而导致暂时故障。因此，当为 CIED 患者使用剂量率>8 Gy/min 的 X 射线时，临床医生应意识到发生故障的风险，并管理好患者的移动。
