Mouton J, Haug R, Bridier A, Dodinot B, Eschwege F
Commissariat a l'Energie Atomique, Bruyères-le-Châtel, France.
Phys Med Biol. 2002 Aug 21;47(16):2879-93. doi: 10.1088/0031-9155/47/16/304.
In this paper, we determine the influence of high-energy photon beam irradiation used for external radiotherapy on pacemakers, at different doses and dose rates. Ninety-six pacemakers of various origins and ages underwent in vitro high-energy photon irradiation under technical conditions close to external radiotherapy, using a linear accelerator delivering photons of high energy (18 MV). Various dose levels (up to 200 Gy for certain particularly resistant pacemakers) were delivered to pacemakers located in a water-equivalent phantom with several dose rates (from 0.05 to 8 Gy min(-1)). Observed failures were sorted into eight classes of progressive harmfulness, some of them possibly lethal. One irradiated pacemaker exhibited an important defect at a dose rate of 0.2 Gy min(-1), for a cumulative dose of 0.15 Gy. Two pacemakers showed an important defect at a cumulative dose of 1 Gy, while nine pacemakers failed at a cumulative dose lower than or equal to 2 Gy and 13 failed at a cumulative dose lower than or equal to 5 Gy. The most important failure probability (70% of irradiated pacemakers) is observed for 8 Gy min(-1), whereas no pacemakers failed at a dose rate lower than or equal to 0.2 Gy min(-1). In conclusion, warnings given by manufacturers about the maximum tolerable cumulative radiation doses for safe operation of irradiated pacemakers (5 Gy), even reduced to 2 Gy, are not reliable. The spread of cumulative doses inducing failures is very large since our observations show an important failure at 0.15 Gy, while ten pacemakers withstood more than 140 Gy of cumulative dose. The safe operation of pacemakers under irradiation depends mainly on type and model. It depends also on dose rate. From our observations, for the safe operation of pacemakers, a recommendation of a maximum dose rate of 0.2 Gy min(-1) rejecting direct irradiation of the pacemaker at a standard dose rate for tumour treatment (2 Gy min(-1)) is made.
在本文中，我们确定了用于体外放射治疗的高能光子束照射在不同剂量和剂量率下对起搏器的影响。96个不同产地和使用年限的起搏器在接近体外放射治疗的技术条件下，使用一台能产生高能（18兆伏）光子的直线加速器进行了体外高能光子照射。将不同剂量水平（某些特别抗辐射的起搏器可达200戈瑞）以几种剂量率（从0.05至8戈瑞·分钟⁻¹）施加于置于水等效体模中的起搏器上。观察到的故障被分为八类，危害程度逐渐增加，其中一些可能是致命的。一个受照射的起搏器在剂量率为0.2戈瑞·分钟⁻¹、累积剂量为0.15戈瑞时出现了严重故障。两个起搏器在累积剂量为1戈瑞时出现严重故障，而九个起搏器在累积剂量低于或等于2戈瑞时出现故障，13个在累积剂量低于或等于5戈瑞时出现故障。在剂量率为8戈瑞·分钟⁻¹时观察到最高的故障概率（70%的受照射起搏器），而在剂量率低于或等于0.2戈瑞·分钟⁻¹时没有起搏器出现故障。总之，制造商给出的关于受照射起搏器安全运行的最大可耐受累积辐射剂量（5戈瑞）的警告，即使降至2戈瑞，也是不可靠的。导致故障的累积剂量范围非常大，因为我们的观察显示在0.15戈瑞时出现了严重故障，而十个起搏器承受了超过140戈瑞的累积剂量。起搏器在照射下的安全运行主要取决于型号和款式。它还取决于剂量率。根据我们的观察，为确保起搏器安全运行，建议最大剂量率为0.2戈瑞·分钟⁻¹，避免以肿瘤治疗的标准剂量率（2戈瑞·分钟⁻¹）直接照射起搏器。
