Investigation of the influence of ionizing radiation on active implantable medical devices and the development of a standardized test method.
The test method will provide a safety evaluation of AIMDs and their interaction with ionizing radiation with the following features:
Advantages for end-user and patients:
As part of the ever-growing number of medical diagnoses and the improvement of diagnostic possibilities, life expectancy has increased dramatically in recent decades. As a consequence of the increasingly aging population, the incidence of heart disease and the corresponding number of implanted pacemakers or cardioverter defibrillators (ICDs) is increasing [2, 3, 4].
Besides active cardiac implants also implants from neurology and audiology are relevant. In addition, there is an emerging group of patients with cancer relying on different kinds of diagnostic and therapeutic modalities. In modern applied diagnostic and therapeutic procedures (radiology, nuclear medicine, radiotherapy) ionizing radiation is widely used. This can bear an unpredictable risk for the proper function of the active implant.
It is known that electronic circuits are destroyed by direct and scattered photons and electrons, which affects the functionality of the implant temporarily or even permanently [5, 6]. In pacemakers, ICD’s, and other active implants such as cochlear implants this can lead to disastrous consequences for the patient .
A future regulation of the European Parliament will deal in detail with these security risks. A first DEGRO/DKG directive on this subject was published in 2015 by Gauter-Fleckenstein et al. . In the end all medical products should be designed in such a way that any risk of ionizing radiation during diagnostic and therapeutic procedures can be excluded . In order to meet this future regulation test methods are needed in the near future that ensure a safe operation of the implant during an increased radiation dose.
Several previous studies have already investigated the influence of ionizing radiation on active medical implants (e.g., [10, 11, 12]). However, due to different test setups in these publications, no reliable conclusion about the maximum applicable dose could be drawn. Furthermore, many studies were individual case reports, which are difficult to compare due to highly varying conditions [13, 14, 15].
Manufacturers of active medical implants have merely issued sporadic recommendations for the maximum tolerated dose of radiation. Depending on the manufacturer, this cumulative dose for several pacemakers varies between 2-5 Gy. For some implants, malfunction occurred even below this dose .
Besides this, usually only the total dose is taken into account, while the enormous influence of and the dependency of device malfunction on the dose rate, as described in Blamires et al. , often is not included in the results. Moreover, pacemakers manufactured within the last three decades (so-called modern pacemakers) seem to be particularly sensitive to ionizing radiation . This is due to their metal-oxide-semiconductor (CMOS) components. These have the advantage of a low operating voltage and low power consumption, but their disadvantage is a very low resistance to ionizing photons. In contrast, older models (early pacemakers), which are still based on bipolar semiconductor devices, have been proven to be more resistant to ionizing radiation. Due to this, in particular newer models experience a malfunction or device failure under to the influence of high-energy ionizing radiation.
Additionally it should be mentioned that malfunction or device failures were not limited to implant positions within the direct radiation field, but also occurred outside this field. This can be attributed to scattered radiation , which is considered to be less hazardous.
|1||Sundar, S. 2005. Radiotherapy to patients with artificial cardiac pacemakers. Cancer Treatment Reviews. 2005, 31.|
|2||Fachgruppe Herzschrittmacher und AQUA: Jahresbericht 2013 des Deutschen Herzschrittmacher- und Defibrillatorregisters. Teil 1: Herzschrittmacher. 2013.|
|3||Fachgruppe Herzschrittmacher und AQUA: Jahresbericht 2013 des Deutschen Herzschrittmacher- und Defibrillatorregisters. Teil 2: Implantierbare Cardioverter-Defibrillatoren (ICD). 2013.|
|4||Fachgruppe Herzschrittmacher und AQUA: Jahresberichte 2010-2013 des Deutschen Herzschrittmacher- und Defibrillatorregisters. Teile 1 und 2.|
|5||Rodriguez, F., Filimonov A., Henning A., et. al. 1991: Radiation-Induced Effects in Multiprogrammable Pacemakers and Implantable Defibrillators. Pace, Vol. 14, 2005.|
|6||Blamires N. G., Myatt J. 1982: X-Ray Effects on Pacemaker Type Circuits. Pace Vol. 5, 1982.|
|7||Dorenkamp, M. 2013. Strahlentherapie bei Patienten mit Herzschrittmachern oder implantierbaren Kardioverter-Defibrillatoren. Strahlentherapie und Onkologie. 2013, 189.|
|8||Gauter-Fleckenstein B., Isreal C. W., Dorenkamp M., et. al. 2015: DEGRO/DKG guideline for radiotherapy in patients with cardiac implantable electronic devices. Strahlenther Onkol (2015): 393-404.|
|9||Verordnung Europ. Parlament: Vorschlag für eine VERORDNUNG DES EUROPÄISCHEN PARLAMENTS UND DES RATES über Medizinprodukte und zur Änderung der Richtlinie 2001/83/EG, der Verordnung (EG) Nr. 178/2002 und der Verordnung (EG) Nr. 1223/2009 /* COM/2012/0542 final - 2012/0266 (COD) */. Link: http://eur-lex.europa.eu/legal-content/DE/ALL/?uri=CELEX%3A52012PC0542 (letzter Zugriff: 02.08.2016).|
|10||Wilm M., Kronholz HL., Schutz J., Koch T. 1994: The modification of programmable pacemakers by therapeutic irradiation. Strahlenther Onkol. 170(4): 225–31.|
|11||Souliman SK., Christie J. 1994: Pacemaker failure induced by radiotherapy. Pacing Clin Electrophysiol 1994. 17(3 Pt 1): 270–3.|
|12||Ngu SL, O’Meley P, Johnson N, Collins C. 1993: Pacemaker function during irradiation: in vivo and in vitro effect. Australas Radiol 1993; 37(1): 105–7.|
|13||Brooks C., Mutter M. 1988: Pacemaker failure associated with therapeutic radiation. Am J Emerg Med 1988. 6(6):591–3.|
|14||Raitt MH., Stelzer KJ., Laramore GE., et al. 1994: Runaway pacemaker during high-energy neutron radiation therapy. Chest 1994. 106(3): 955–7.|
|15||Lee RW., Huang SK., Mechling E., Bazgan I. 1986: Runaway atrioventricular sequential pacemaker after radiation therapy. Am J Med 1986. 81(5): 883–6.|
|16||Mouton J., Haug R., Bridier A., et. al. 2002: Influence of high-energy photon beam irradiation on pacemaker operation. Physics in Medicine and Biology. 2002. 47: 2879-2893|
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