Prediction of radiation‐induced malfunction for cardiac implantable electronic devices (CIEDs)

Abstract

Purpose Cardiac implantable electronic devices (CIEDs) were believed to possess a tolerance dose to malfunction during radiotherapy. Although recent studies have qualitatively suggested neutrons as a cause of malfunction, numerical understanding has not been reached. The purpose of this work is to quantitatively clarify the contribution of secondary neutrons from out‐of‐field irradiation to the malfunction of CIEDs as well as to deduce the frequency of malfunctions until completion of prostate cancer treatment as a typical case. Materials and Methods Measured data were gathered from the literature and were re‐analyzed. Firstly, linear relationship for a number of malfunctions to the neutron dose was suggested by theoretical consideration. Secondly, the accumulated number of malfunctions of CIEDs gathered from the literature was compared with the prescribed dose, scattered photon dose, and secondary neutron dose for analysis of their correlation. Thirdly, the number of malfunctions during a course of prostate treatment with high‐energy X‐ray, passive proton, and passive carbon‐ion beams was calculated while assuming the same response to malfunctions, where X‐rays consisted of 6‐MV, 10‐MV, 15‐MV, and 18‐MV beams. Monte Carlo simulation assuming simple geometry was performed for the distribution of neutron dose from X‐ray beams, where normalization factors were applied to the distribution so as to reproduce the empirical values. Results Linearity between risk and neutron dose was clearly found from the measured data, as suggested by theoretical consideration. The predicted number of malfunctions until treatment completion was 0, 0.02 ± 0.01, 0.30 ± 0.08, 0.65 ± 0.17, 0.88 ± 0.50, and 0.14 ± 0.04 when 6‐MV, 10‐MV, 15‐MV, 18‐MV, passive proton, and passive carbon‐ion beams, respectively, were employed, where the single model response to a malfunction of 8.6 ± 2.1 Sv−1 was applied. Conclusions Numerical understanding of the malfunction of CIEDs has been attained for the first time. It has been clarified that neutron dose is a good scale for the risk of CIEDs in radiotherapy. Prediction of the frequency of malfunction as well as discussion of the risk to CIEDs in radiotherapy among the multiple modalities have become possible. Because the present study quantitatively clarifies the neutron contribution to malfunction, revision of clinical guidelines is suggested.

Particle therapy using protons or carbon ions for cancer patients with cardiac implantable electronic devices (CIED): a retrospective multi-institutional study

“…This can be a reason why fewer secondary neutrons are produced in CIT than in PBT. Also, the previous dosimetric studies suggested that CIT produces fewer secondary neutrons than PBT even for the same physical absorbed dose in Gy [20,26].…”

“…There was no institution which used scanning beams in this study. It has been suggested that scanning particle beam therapy can reduce the secondary neutron volume dramatically [16,17,20,26]. Seidansaal et al have reported that there were no device malfunctions among 32 patients (10 PBT and 22 CIT) with CIED in their investigation [27].…”

A Review and Analysis of Managing Commonly Seen Implanted Devices for Patients Undergoing Radiation Therapy

“…17 Therefore, each patient needs to be considered individually and recognition of the patient's dependence on the CIED identified. If the patient is pacing-dependent, it is usually not recommended to treat them with proton therapy, 45 , 46 , 49 especially in standalone centers with limited resources. Likewise, for the pacing independent patient, risks should be evaluated before delivering proton therapy.…”

Implantable cardiac pacemaker failure by cumulative dose effects of flattening filter free beams

“…The wide range of doses that cause failure indicates that there are the differences in dosage depending on the radiation type, the radiation energy, and the radiation quality [ 15 ]. However, the failure that occurs at cumulative dose of ≤1 Gy may be related to neutron-induced disturbances instead of cumulative dose effects [ 16 ]. Therefore, it is considered that CIEDs have a higher risk of failure at cumulative doses >5 Gy, and most guidelines recommend cumulative dose thresholds for CIEDs for patients undergoing radiotherapy [ 4 , 7–10 ].…”