Analyzing the influence of ionizing radiation on active implants and developing a standardized test method.
A joint project by MR:comp GmbH & Ostbayerische Technische Hochschule Amberg-Weiden (OTH-AW). This work is supported by the German Federal Ministry of Education and Research (BMBF), grant # ZF4205702AW6.

About us

OTH

The X-Ray & Molecular Imaging Laboratory is a research laboratory which is located at the Institute of Medical Technology (IfMZ) of Eastern Bavarian Technical Colleges Amberg-Weiden (OTH). Prof. Dr. Ralf Ringler and his team are mainly engaged in Medical Physics (radiology, nuclear medicine and radiotherapy) and imaging in medical diagnosis and therapy.
The existing facilities of laboratories with CT, SPECT and PET as well as cooperation to clinics Nordoberpfalz AG , Amberg and Nürnberg makes it possible to have access to other equipment such as linear accelerators. The interdisciplinary nature and wide-ranging expertise of the institute is the basis for an implementation of the IIIRay project that is both scientifically based and application oriented.
The task and the challenge of the team is the investigation of the influence of ionizing radiation on active implants from a purely scientific, nonmonetary point of view. The project will be conducted both theoretically and experimentally in a systematic and standardized way and includes the publication and discussion of the results in a scientific context, e.g. at conferences and scientific meetings.



MR:comp

MR:comp GmbH was founded in 2004 by Mr. Gregor Schaefers and has established itself within a few years as a special service provider for MR safety testing of implants and other medical devices. These are tested for various hazardous interactions with the different field types of the MR system (static magnetic field, radio frequency field, gradient magnetic field). The tests comply with methods of the relevant ASTM and ISO/TS standards and are conducted under consideration of quality management according to ISO 17025.
In addition to passive implants and accessories, various types of active implants like cochlear implants, ICDs, and neurostimulators of manufacturers around the world are tested. While interactions of medical devices with the MR environment have been extensively studied and described, available data for active implants under the influence of ionizing radiation is significantly less. Therefore, this project will investigate basic interactions and identify essential hazards of these implants with ionizing radiation.
Our experience in MR safety with the implementation and execution of the necessary functional tests can be transferred to the new field of ionizing radiation and will allow us to rapidly develop a reliable standardized test method.

Our goals

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:

  • Reproducibility and reliability of results using a standardized in-vitro measurement setup
  • Practice-oriented tests to match clinical conditions
  • Variability for different radiation sources and energies
  • Universally applicable for all kinds of active implants
  • Individually customizable to match your needs

Advantages for end-user and patients:

  • New standardized method for safety evaluation of AIMDs
  • Dose limits for safe use during radiotherapy or imaging
  • Increased patient safety
  • Independently proven safety

Background

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 [7].
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. [8]. 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 [9]. 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.

Current research

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 [16].
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. [6], 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 [1]. 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 [1], which is considered to be less hazardous.

Quellen:

Ziffer Beschreibung
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

Contact

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Support us with your experience, knowledge or providing test objects for research and development purposes for this project and receive benefit from the results!

Supported by: Federal Ministry for Economic Affairs and Energy on the basis of a decision by the German Bundestag, grant # ZF4205702AW6.



Imprint

MR:comp GmbH
Buschgrundstr. 23 (mailing address)
Buschgrundstr. 33 (registered office)
45894 Gelsenkirchen
Germany


fon +49 209-1497730-0
fax +49 209-1497730-88
info@mrcomp.com


Managing Director
Dipl.-Ing. (FH) Gregor Schaefers


Amtsgericht Gelsenkirchen HRB 7676