Vagus nerve stimulator stability and interference on radiation oncology x-ray beams

Safety and Management of Implanted Epilepsy Devices for Imaging and Surgery

Permanently implanted devices that deliver electrical stimulation are increasingly used to treat patients with drug-resistant epilepsy. Primary care physicians, neurologists, and epilepsy clinicians may encounter patients with a variety of implanted neuromodulation devices in the course of clinical care. Due to the rapidly changing landscape of available epilepsy-related neurostimulators, there may be uncertainty related to how these devices should be handled during imaging procedures and perioperative care. We review the safety and management of epilepsy-related implanted neurostimulators that may be encountered during imaging and surgery. We provide a summary of approved device labeling and recommendations for the practical management of these devices to help guide clinicians as they care for patients treated with bioelectronic medicine.

Radiotherapy for a Patient With Spinal Cord Stimulation: A Case Report

Cancer-related neuropathic pain is prevalent in up to 40% of patients with advanced disease. Spinal cord stimulation (SCS) is used to treat chronic pain when other treatments are ineffective. Radiotherapy is an established treatment modality for patients with oncological diseases. The ionizing radiation from radiotherapy can potentially damage electrical devices, including SCS devices. Additionally, all parts of SCS can potentially interfere with radiotherapy delivery. We present a case of successful administration of radiotherapy to a patient without damaging the SCS device implanted in proximity to the target lesion.

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

Purpose

This review article aims to consolidate information regarding existing and emerging implanted devices used in patients undergoing radiation therapy and to categorize levels of attention needed for each device, including which devices require monitoring throughout treatment.

Methods and Materials

Based on the collective information from scholar searches, manufacturers' technical reports, and institutional experiences in the past years, commonly present devices in patients with cancer are compiled. This work summarizes cardiac pacemaker, implanted cardiac defibrillator, hepatic pump, intrathecal pain pump, neurostimulator, shunt, loop recorder, and mediport. Three different classifications of implanted devices can be made based on the potential effect of radiation: life-dependent, nonlife-dependent but with adverse effects if overdosed, and devices without electronic circuits. Implanted devices that contain electronic circuits that would be life-dependent or have adverse effects if overdosed, include cardiac pacemakers, implanted cardiac defibrillators, programmable hepatic pumps, pain pumps, neurostimulators, and loop recorders.

Results

Dose exposure to these devices need to be calculated or measured in vivo, especially for cardiac implanted devices, and they should be minimized to assure continued healthy functioning. Treatment planning techniques should be chosen to reduce entry, exit and internal scatter dose. Lower energy photon beams should be used to decrease potential neutron contamination. Implanted devices without electronic circuits are less of a concern. If a patient is life-dependent on the implanted device, it is not recommended to treat the patient with proton therapy.

Conclusions

This study reviewed the management of patients with commonly seen implanted devices and summarized a workflow for identifying and planning when a patient has implanted devices. Classifications of implanted devices could help clinicians make proper decisions in regard to patients with specific implanted devices. Lastly, the management of such devices in the era of the pandemic is also discussed in this review article.

Management of radiotherapy patients with implanted cardiac pacemakers and defibrillators: A Report of the AAPM TG-203†

Managing radiotherapy patients with implanted cardiac devices (implantable cardiac pacemakers and implantable cardioverter-defibrillators) has been a great practical and procedural challenge in radiation oncology practice. Since the publication of the AAPM TG-34 in 1994, large bodies of literature and case reports have been published about different kinds of radiation effects on modern technology implantable cardiac devices and patient management before, during, and after radiotherapy. This task group report provides the framework that analyzes the potential failure modes of these devices and lays out the methodology for patient management in a comprehensive and concise way, in every step of the entire radiotherapy process.

Preserved vagus nerve stimulator function after radiation therapy

BACKGROUND

Epilepsy and breast cancer are both prevalent conditions. A subset of women with medically refractory epilepsy and vagus nerve stimulators (VNS) may later develop breast cancer and may require adjuvant radiation as part of their treatment regimen. However, to date, little data are available on the effects of radiation on VNS function.

CASE PRESENTATION

We present a young woman with tuberous sclerosis, developmental delay, and medically refractory epilepsy who developed left-sided breast cancer. Her epilepsy became controlled with a recent addition of a VNS implanted in her left chest wall. She required adjuvant radiation therapy to her left breast, and this raised the novel question of the safety of radiation on the integrity and functioning of the device, which we explore in this article.

CONCLUSION

This case is the first report of a patient with VNS for epilepsy and breast cancer who received radiation therapy proximal to the device. The device continued to function properly despite the exposure.

Radiation Testing of the GERD Stimulation Therapy System Using a Particle Accelerator

OBJECTIVE

This testing was conducted to determine if exposure from a particle accelerator used to treat cancer patients would alter the performance of the EndoStim® neurostimulator when programmed either passively or actively and while being irradiated.

METHODS

A total of 12 EndoStim Lower Esophageal Sphincter (LES) Stimulation System implantable neurostimulators were investigated in this research. Included were six each of the EndoStim I and EndoStim II. Half were used for passive testing, with the remaining half for active testing. Bremsstrahlung x-rays were delivered having a nominal energy of 18 MV at a rate of 6 Gy/min. A total dose of 80 Gy was achieved in testing minimally.

RESULTS

Monitoring of stimulation frequency, amplitude, pulse width, stimulation time, and voltage was conducted using software developed by EndoStim along with an oscilloscope. No observed changes to the intended stimulation were noted and all scheduled parameter magnitudes were achieved with device operation. All functional parameter changes were within ±10% from baseline.

CONCLUSIONS

EndoStim I and EndoStim II implant pulse generators appear to be immune to x-ray radiation from the particle accelerator at energies up to 18 MV, at dose rates of up to 6 Gy/min, and up to cumulative doses of minimally 80 Gy. As there were no observable effects on neurostimulation requirements, the EndoStim LES Stimulation System implantable neurostimulators are capable of withstanding direct radiation. The recommendations of the manufacturer should be followed further regarding the labeling requirements for insured safety to patients.