Proton beam therapy interference with implanted cardiac pacemakers.
OBJECTIVE
To investigate the effect of proton beam therapy (PBT) on implanted cardiac pacemaker function.


METHODS
After a phantom study confirmed the safety of PBT in patients with cardiac pacemakers, we treated 8 patients with implanted pacemakers using PBT to a total tumor dose of 33-77 gray equivalents (GyE) in dose fractions of 2.2-6.6 GyE. The combined total number of PBT sessions was 127. Although all pulse generators remained outside the treatment field, 4 patients had pacing leads in the radiation field. All patients were monitored by means of electrocardiogram during treatment, and pacemakers were routinely examined before and after PBT.


RESULTS
The phantom study showed no effect of neutron scatter on pacemaker generators. In the study, changes in heart rate occurred three times (2.4%) in 2 patients. However, these patients remained completely asymptomatic throughout the PBT course.


CONCLUSIONS
PBT can result in pacemaker malfunctions that manifest as changes in pulse rate and pulse patterns. Therefore, patients with cardiac pacemakers should be monitored by means of electrocardiogram during PBT.
Department of Radiation Oncology, University of Tsukuba, Ibaraki, Japan.
Yoshiko
Y
Oshiro
Shinji
S
Sugahara
Mio
M
Noma
Masato
M
Sato
Yuzuru
Y
Sakakibara
Takeji
T
Sakae
Yasutaka
Y
Hayashi
Hidetsugu
H
Nakayama
Koji
K
Tsuboi
Nobuyoshi
N
Fukumitsu
Ayae
A
Kanemoto
Takayuki
T
Hashimoto
Koichi
K
Tokuuye
D000368:Aged; D000369:Aged, 80 and over; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D004562:Electrocardiography; D004867:Equipment Design; D005260:Female; D006327:Heart Block / Q000209:etiology*; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000532:radiotherapy*; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D019047:Phantoms, Imaging; D061766:Proton Therapy; D011522:Protons / Q000009:adverse effects; D011878:Radiotherapy / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage; D012542:Scattering, Radiation; D016896:Treatment Outcome
D011522:Protons