INTRODUCTION

1. INFLUENCE OF RADIOTHERAPY ON THE LATEST GENERATION OF PACEMAKERSEgon Scheepers1, Bob Springorum2, Hans Uiterwaal2 , Coen Hurkmans31 Eindhoven University of technology, Department of biomedical Engineering, Eindhoven, The Netherlands2Onze Lieve Vrouwe Gasthuis, Department of Cardiology, Amsterdam, The Netherlands 3Catharina Hospital, Department of Radiotherapy, Eindhoven, The Netherlands, e-mail: coen.hurkmans@cze.nl, Onze Lieve Vrouwe Gasthuis Catharina Hospital • RESULTS • 14 out of 19 pacemakers reached a point of failure. • One device permanently lost telemetry after 20 Gy. • All other points of failure revealed themselves after more than 80 Gy. • 5 pacemakers showed an Elective Replacement Indication. This warning is a result of a low battery voltage. • 3 pacemakers lost telemetry. • 7 pacemakers lost output, of which all but one recovered after one week. • 2 pacemakers had problems with their sense channel at 120 Gy. • 5 pacemakers did not show any error. All these devices (numbers 10-13 and 15) where from the same manufacturer. • Table 1. Results for all 19 pacemakers. Eight out of 19 pacemakers exhibited inhibitions during irradiation (data not shown). Type of malfunction is indicated together with the dose level(s) at which the malfunction manifested. In the last column the definite point of failure is specified together with the dose level at which this occurred. Pacemakers 8 and 17 were erroneously irradiated to 130 Gy instead of 120 Gy. Final: measurement performed approximately 1-2 weeks after the last irradiation fraction. INTRODUCTION Radiotherapy can influence the functioning of pacemakers. Guidelines for radiotherapy treatment of patients with a pacemaker have been published in 1994 by The American Association of Physicists in Medicine (AAPM), and are based on relatively old data of old pacemaker types. OBJECTIVE to determine the influence of radio- therapy on modern pacemakers. MATERIALS AND METHODS 19 new and modern pacemakers have been irradiated in our department using a 6 MV beam. The given dose was fractionated up to a cumulative dose of 120 Gy. Two to five days were kept between consecutive irradiations. Frequency, output, sensing, telemetry and battery status were monitored. CONCLUSIONS The newest generation of pacemakers exhibit a variety of radiation induced defects. However, most malfunctions were observed at dose levels exceeding 20 Gy. This is comparable to results observed for older pacemaker types. Thus, the AAPM guidelines still seem to be valid. Figure 1. Oscilloscope and Cenelec pulse generator used at measurements Figure 2. pacemaker within irradiation phantom attached to a 510 Ohm resistance to simulate the heart load.