Photoneutron-induced damage reduction for cardiac implantable electronic devices using neutron-shielding sheets in high-energy X-ray radiotherapy: A phantom study

As a base material for semiconductor devices, silicon is more widely used than any other semiconductor. The physical properties, in particular the bandgap which is significantly larger than that of germanium, makes the material extremely important for electronic devices. The world's total annual production of silicon is at present some 2000 t [1]. Compared with this, the 10 kg/year of silicon that is used for detectors is rather modest. However, since work on semiconductor radiation detectors started 25 years ago, silicon in addition to germanium forms the centre of interest as the basis for production of nuclear radiation spectrometers, mainly as high energy particle detectors, but also as X-ray detectors.

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Effect of X-ray dose rates higher than 8 Gy/min on the functioning of cardiac implantable electronic devices

Journal of Radiation Research ◽

10.1093/jrr/rraa016 ◽

2020 ◽

Vol 61 (3) ◽

pp. 419-425 ◽

Cited By ~ 1

Author(s):

Kazuhiko Nakamura ◽

Takahiro Aoyama ◽

Naoki Kaneda ◽

Masashi Otsuji ◽

Yoshitaka Minami ◽

...

Keyword(s):

Dose Rate ◽

Treatment Plan ◽

Electronic Devices ◽

Normal Function ◽

X Ray ◽

Dose Rates ◽

Cardiac Implantable Electronic Devices ◽

Flattening Filter Free ◽

Direct Irradiation ◽

Flattening Filter

Abstract Direct irradiation may cause malfunctioning of cardiac implantable electronic devices (CIEDs). Therefore, a treatment plan that does not involve direct irradiation of CIEDs should be formulated. However, CIEDs may be directly exposed to radiation because of the sudden intrafractional movement of the patient. The probability of CIED malfunction reportedly depends on the dose rate; however, reports are only limited to dose rates ≤8 Gy/min. The purpose of this study was to investigate the effect of X-ray dose rates >8 Gy/min on CIED function. Four CIEDs were placed at the center of the radiation field and irradiated using 6 MV X-ray with flattening filter free (6 MV FFF) and 10 MV X-ray with flattening filter free (10 MV FFF). The dose rate was 4–14 Gy/min for the 6 MV FFF and 4–24 Gy/min for 10 MV FFF beams. CIED operation was evaluated with an electrocardiogram during each irradiation. Three CIEDs malfunctioned in the 6 MV FFF condition, and all four CIEDs malfunctioned in the 10 MV FFF condition, when the dose rate was >8 Gy/min. Pacing inhibition was the malfunction observed in all four CIEDs. Malfunction occurred simultaneously along with irradiation and simultaneously returned to normal function on stopping the irradiation. An X-ray dose rate >8 Gy/min caused a temporary malfunction due to interference. Therefore, clinicians should be aware of the risk of malfunction and manage patient movement when an X-ray dose rate >8 Gy/min is used for patients with CIEDs.

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High-purity Ge x-ray detectors: Sensitivity factors and usefulness

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136350 ◽

1990 ◽

Vol 48 (2) ◽

pp. 548-548

Author(s):

E. B. Steel

Keyword(s):

High Purity ◽

High Energy ◽

Quantitative Chemical Analysis ◽

Detector Performance ◽

X Ray ◽

Detector Sensitivity ◽

Specimen Holder ◽

Many Instruments ◽

Charge Resolution ◽

Sensitivity Factors

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

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Designing high-resolution slow scan CCD-based TEM camera systems

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012936x ◽

1992 ◽

Vol 50 (2) ◽

pp. 946-947

Author(s):

James F. Mancuso ◽

William B. Maxwell ◽

Russell E. Camp ◽

Mark H. Ellisman

Keyword(s):

Fiber Optics ◽

Ccd Camera ◽

High Energy ◽

Phosphor Layer ◽

X Ray ◽

Light Production ◽

Camera Systems ◽

X Ray Imaging ◽

Electron Image ◽

Scintillating Fiber

The imaging requirements for 1000 line CCD camera systems include resolution, sensitivity, and field of view. In electronic camera systems these characteristics are determined primarily by the performance of the electro-optic interface. This component converts the electron image into a light image which is ultimately received by a camera sensor.Light production in the interface occurs when high energy electrons strike a phosphor or scintillator. Resolution is limited by electron scattering and absorption. For a constant resolution, more energy deposition occurs in denser phosphors (Figure 1). In this respect, high density x-ray phosphors such as Gd2O2S are better than ZnS based cathode ray tube phosphors. Scintillating fiber optics can be used instead of a discrete phosphor layer. The resolution of scintillating fiber optics that are used in x-ray imaging exceed 20 1p/mm and can be made very large. An example of a digital TEM image using a scintillating fiber optic plate is shown in Figure 2.

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The Basic Physical Principles of Ion, Electron, and X-Ray Detectors and Their Application to Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117777 ◽

1985 ◽

Vol 43 ◽

pp. 154-157

Author(s):

A.J. Tousimis

Keyword(s):

Ion Beam ◽

Depth Resolution ◽

Sample Surface ◽

High Energy ◽

X Rays ◽

X Ray ◽

Electrons And Ions ◽

Spatial Depth ◽

Minimum Surface Area ◽

Physical Principles

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.

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Recent Advances in Pacing and Defibrillation

Asia Pacific Cardiology ◽

10.15420/apc.2011:3:1:74 ◽

2011 ◽

Vol 3 (1) ◽

pp. 74

Author(s):

Kathy L Lee ◽

Keyword(s):

Cardiac Death ◽

Electronic Devices ◽

Implantable Defibrillators ◽

Cardiac Pacemakers ◽

Cardiac Implantable Electronic Devices ◽

Treatment And Prevention ◽

Recent Advances ◽

Pacing Lead ◽

Leadless Pacing ◽

Device Complications

Cardiac pacemakers have been the standard therapy for patients with bradyarrhythmias for several decades. The pacing lead is an integral part of the system, serving as a conduit for the delivery of energy pulses to stimulate the myocardium. However, it is also the Achilles’ heel of pacemakers, being the direct cause of most device complications both acutely during implant and chronically years afterwards. Leadless pacing with ultrasound-mediated energy has been demonstrated in animals and humans to be safe and feasible in acute studies. Implantable defibrillators revolutionised the treatment and prevention of sudden cardiac death. Subcutaneous implantable defibrillators have been under development for more than 10 years. A permanent implantable system has been shown to be feasible in treating induced and spontaneous ventricular tachyarrhythmias. These developments and recent advances in pacing and defibrillation will arouse further interest in the research and development of leadless cardiac implantable electronic devices.

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Utilisation of High-Energy Heat Sources in Magnesium Alloy Surface Layer Treatment

Archives of Metallurgy and Materials ◽

10.2478/amm-2013-0047 ◽

2013 ◽

Vol 58 (2) ◽

pp. 619-624 ◽

Cited By ~ 2

Author(s):

M. Szafarska ◽

J. Iwaszko ◽

K. Kudła ◽

I. Łegowik

Keyword(s):

Surface Layer ◽

Magnesium Alloy ◽

Physicochemical Properties ◽

Treatment Effectiveness ◽

High Energy ◽

Alloy Surface ◽

Heat Sources ◽

X Ray ◽

Additional Equipment ◽

Alloy Surface Layer

The main aim of the study was the evaluation of magnesium alloy surface treatment effectiveness using high-energy heat sources, i.e. a Yb-YAG Disk Laser and the GTAW method. The AZ91 and AM60 commercial magnesium alloys were subject to surface layer modification. Because of the physicochemical properties of the materials studied in case of the GTAW method, it was necessary to provide the welding stand with additional equipment. A novel two-torch set with torches operating in tandem was developed within the experiment. The effectiveness of specimen remelting using a laser and the GTAW method was verified based on macro- and microscopic examinations as well as in X-ray phase analysis and hardness measurements. In addition, the remelting parameters were optimised. The proposed treatment methodology enabled the achieving of the intended result and effective modification of a magnesium alloy surface layer.

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