Low Z total reflection X-ray fluorescence analysis — challenges and answers

NASA Astrophysics Data System (ADS)

Streli, C.; Kregsamer, P.; Wobrauschek, P.; Gatterbauer, H.; Pianetta, P.; Pahlke, S.; Fabry, L.; Palmetshofer, L.; Schmeling, M.

1999-10-01

Low Z elements, like C, O, ... Al are difficult to measure, due to the lack of suitable low-energy photons for efficient excitation using standard X-ray tubes, as well as difficult to detect with an energy dispersive detector, if the entrance window is not thin enough. Special excitation sources and special energy dispersive detectors are required to increase the sensitivity and to increase the detected fluorescence signal and so to improve the detection limits. Synchrotron radiation, due to its features like high intensity and wide spectral range covering also the low-energy region, is the ideal source for TXRF, especially of low-Z elements. Experiments at a specific beamline (BL 3-4) at SSRL, Stanford, designed for the exclusive use of low-energy photons has been used as an excitation source. Detection limits <100 fg for Al, Mg and Na have been achieved using quasimonochromatic radiation of 1.7 keV. A Ge(HP) detector with an ultra-thin NORWAR entrance window is used. One application is the determination of low-Z surface contamination on Si-wafers. Sodium, as well as Al, are elements of interest for the semiconductor industry, both influencing the yield of ICs negatively. A detection capacity of 10 10 atoms/cm 2 is required which can be reached using synchrotron radiation as excitation source. Another promising application is the determination of low-Z atoms implanted in Si wafers. Sodium, Mg and Al were implanted in Si-wafers at various depths. From measuring the dependence of the fluorescence signal on the glancing angle, characteristic shapes corresponding to the depth profile and the relevant implantation depth are found. Calculations are compared with measurements. Finally, aerosols sampled on polycarbonate plates in a Battelle impactor were analyzed with LZ-TXRF using multilayer monochromatized Cr-Kα radiation from a 1300-W fine-focus tube for excitation. Results are presented.

Electromagnetic Radiation Efficiency of Body-Implanted Devices

NASA Astrophysics Data System (ADS)

Nikolayev, Denys; Zhadobov, Maxim; Karban, Pavel; Sauleau, Ronan

2018-02-01

Autonomous wireless body-implanted devices for biotelemetry, telemedicine, and neural interfacing constitute an emerging technology providing powerful capabilities for medicine and clinical research. We study the through-tissue electromagnetic propagation mechanisms, derive the optimal frequency range, and obtain the maximum achievable efficiency for radiative energy transfer from inside a body to free space. We analyze how polarization affects the efficiency by exciting TM and TE modes using a magnetic dipole and a magnetic current source, respectively. Four problem formulations are considered with increasing complexity and realism of anatomy. The results indicate that the optimal operating frequency f for deep implantation (with a depth d ≳3 cm ) lies in the (108- 109 )-Hz range and can be approximated as f =2.2 ×107/d . For a subcutaneous case (d ≲3 cm ), the surface-wave-induced interference is significant: within the range of peak radiation efficiency (about 2 ×108 to 3 ×109 Hz ), the max-to-min ratio can reach a value of 6.5. For the studied frequency range, 80%-99% of radiation efficiency is lost due to the tissue-air wave-impedance mismatch. Parallel polarization reduces the losses by a few percent; this effect is inversely proportional to the frequency and depth. Considering the implantation depth, the operating frequency, the polarization, and the directivity, we show that about an order-of-magnitude efficiency improvement is achievable compared to existing devices.

TH-C-19A-09: Quantification of Transmission and Backscatter Factors as a function of Distance to Inhomogeneity Interface for Three Types of Surgical Implant Plates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, D; Mills, M; Wang, B

Purpose: Carbon fiber materials have been increasingly used clinically, mainly in orthopedics, as an alternative to metallic implants because of their minimal artifacts on CT and MRI images. This study characterizes the transmission and backscatter property of carbon fiber plates (CarboFix Orthopedics, Herzeliya, Israel) with measurements for radiation therapy applications, and compares them to traditional Stainless Steel (SS) and Titanium (Ti) metal materials. Methods: For the transmission measurements, 1-mm-thick test plate was placed upstream from a plane parallel Markus chamber, separated by various thicknesses of polystyrene plates in 0.5 cm increments between 0 and 5 cm. With this setup, wemore » quantified the radiation transmission as a function of distance to the inhomogeneity interface. The LINAC source to detector distance was maintained at 100 cm and 200 MU was delivered for each measurement. Two 3-cm solid water phantoms were placed at the top and bottom to provide build up. All the measurements were performed for 6 MV and 18 MV photons. The backscatter measurements had the identical setup, except that the test plate was downstream of the chamber from radiation. Results: The carbon fiber plates did not introduce any measureable inhomogeneity effect on the transmission and backscatter factor because of its low atomic number. In contrast, traditional metal implant materials caused up to 15% dose difference at upstream and 25% backscatter at downstream from radiation. Such differences decrease as the distance to the inhomogeneity interface increases and become unmeasurable at distance of 3 cm and 1 cm for upstream and downstream, respectively. Conclusion: A new type of carbon fiber implant plate was evaluated and found to have minimal inhomogeneity effect in MV radiation beams. Patients would benefit from a carbon based implant over metal for radiation therapy due to their minimal backscatter and imaging artifacts.« less

Strength estimation of a moving 125Iodine source during implantation in brachytherapy: application to linked sources.

PubMed

Tanaka, Kenichi; Endo, Satoru; Tateoka, Kunihiko; Asanuma, Osamu; Hori, Masakazu; Takagi, Masaru; Bengua, Gerard; Kamo, Ken-Ichi; Sato, Kaori; Takeda, Hiromitsu; Hareyama, Masato; Sakata, Koh-Ichi; Takada, Jun

2014-11-01

This study sought to demonstrate the feasibility of estimating the source strength during implantation in brachytherapy. The requirement for measuring the strengths of the linked sources was investigated. The utilized sources were (125)I with air kerma strengths of 8.38-8.63 U (μGy m(2) h(-1)). Measurements were performed with a plastic scintillator (80 mm × 50 mm × 20 mm in thickness). For a source-to-source distance of 10.5 mm and at source speeds of up to 200 mm s(-1), a counting time of 10 ms and a detector-to-needle distance of 5 mm were found to be the appropriate measurement conditions. The combined standard uncertainty (CSU) with the coverage factor of 1 (k = 1) was ∼15% when using a grid to decrease the interference by the neighboring sources. Without the grid, the CSU (k = 1) was ∼5%, and an 8% overestimation due to the neighboring sources was found to potentially cause additional uncertainty. In order to improve the accuracy in estimating source strength, it is recommended that the measurment conditions should be optimized by considering the tradeoff between the overestimation due to the neighboring sources and the intensity of the measured value, which influences the random error. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Subcutaneous Photovoltaic Infrared Energy Harvesting for Bio-Implantable Devices.

PubMed

Moon, Eunseong; Blaauw, David; Phillips, Jamie D

2017-05-01

Wireless biomedical implantable devices on the mm-scale enable a wide range of applications for human health, safety, and identification, though energy harvesting and power generation are still looming challenges that impede their widespread application. Energy scavenging approaches to power biomedical implants have included thermal [1-3], kinetic [4-6], radio-frequency [7-11] and radiative sources [12-14]. However, the achievement of efficient energy scavenging for biomedical implants at the mm-scale has been elusive. Here we show that photovoltaic cells at the mm-scale can achieve a power conversion efficiency of more than 17 % for silicon and 31 % for GaAs under 1.06 μW/mm 2 infrared irradiation at 850 nm. Finally, these photovoltaic cells demonstrate highly efficient energy harvesting through biological tissue from ambient sunlight, or irradiation from infrared sources such as used in present-day surveillance systems, by utilizing the near infrared (NIR) transparency window between the 650 nm and 950 nm wavelength range [15-17].

Subcutaneous Photovoltaic Infrared Energy Harvesting for Bio-Implantable Devices

PubMed Central

Moon, Eunseong; Blaauw, David; Phillips, Jamie D.

2017-01-01

Wireless biomedical implantable devices on the mm-scale enable a wide range of applications for human health, safety, and identification, though energy harvesting and power generation are still looming challenges that impede their widespread application. Energy scavenging approaches to power biomedical implants have included thermal [1–3], kinetic [4–6], radio-frequency [7–11] and radiative sources [12–14]. However, the achievement of efficient energy scavenging for biomedical implants at the mm-scale has been elusive. Here we show that photovoltaic cells at the mm-scale can achieve a power conversion efficiency of more than 17 % for silicon and 31 % for GaAs under 1.06 μW/mm2 infrared irradiation at 850 nm. Finally, these photovoltaic cells demonstrate highly efficient energy harvesting through biological tissue from ambient sunlight, or irradiation from infrared sources such as used in present-day surveillance systems, by utilizing the near infrared (NIR) transparency window between the 650 nm and 950 nm wavelength range [15–17]. PMID:29056754

Long-term success of dental implants in patients with head and neck cancer after radiation therapy.

PubMed

Curi, M M; Condezo, A F B; Ribeiro, K D C B; Cardoso, C L

2018-06-01

The purpose of this study was to analyze the long-term success and factors potentially influencing the success of dental implants placed in patients with head and neck cancer who underwent radiation therapy with a minimum total dose of 50Gy during the years 1995-2010. Thirty-five patients (169 dental implants) were included in this study. Data on demographic characteristics, tumour type, radiation therapy, implant sites, implant dimensions, and hyperbaric oxygen therapy (HBOT) were obtained from the medical records and analyzed. Implant survival was estimated using Kaplan-Meier survival curves. Seventy-nine dental implants were placed in the maxilla and 90 in the mandible. The mean follow-up after implant installation was 7.4 years (range 0.3-14.7 years). The overall 5-year survival rate for all implants was 92.9%. Sex (P<0.001) and the mode of radiation therapy delivery (P=0.005) had a statistically significant influence on implant survival. Age, time of implantation after irradiation, implant brand and dimensions, and HBOT had no statistically significant influence on implant survival. Osseointegrated dental implants can be used successfully in the oral rehabilitation of patients with head and neck cancer with a history of radiation therapy. Risk factors such as sex and the mode of radiation therapy delivery can affect implant survival. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Imaging method for monitoring delivery of high dose rate brachytherapy

DOEpatents

Weisenberger, Andrew G; Majewski, Stanislaw

2012-10-23

A method for in-situ monitoring both the balloon/cavity and the radioactive source in brachytherapy treatment utilizing using at least one pair of miniature gamma cameras to acquire separate images of: 1) the radioactive source as it is moved in the tumor volume during brachytherapy; and 2) a relatively low intensity radiation source produced by either an injected radiopharmaceutical rendering cancerous tissue visible or from a radioactive solution filling a balloon surgically implanted into the cavity formed by the surgical resection of a tumor.

Dosimetric measurement of scattered radiation from dental implants in simulated head and neck radiotherapy.

PubMed

Wang, R; Pillai, K; Jones, P K

1998-01-01

The purpose of this study was to examine the dose enhancement at bone-implant interfaces from scattered radiation during simulated head and neck radiotherapy. Three cylindric implant systems with different compositions (pure titanium, titanium-aluminum-vanadium alloy, titanium coated with hydroxyapatite) and a high gold content transmandibular implant system (gold-copper-silver alloy) were studied. Extruded lithium fluoride single crystal chips were used as thermoluminescent material to measure radiation dose enhancement at 0, 1, and 2 mm from the bone-implant interface. The relative doses in buccal, lingual, mesial, and distal directions were also recorded and compared. The results indicated that the highest dose enhancement occurred at a distance of 0 mm from the bone-implant interface for all the implant systems studied. The transmandibular implants had higher scattered radiation than other groups at 0 mm and at 1 mm from the bone-implant interface. There was no significant difference of dose enhancement between buccal, lingual, mesial, and distal directions. Titanium implants coated with hydroxyapatite demonstrated the best results under the simulated irradiation.

Survival of dental implants in native and grafted bone in irradiated head and neck cancer patients: a retrospective analysis.

PubMed

Buddula, Aravind; Assad, Daniel A; Salinas, Thomas J; Garces, Yolanda I

2011-01-01

To study the long-term survival of dental implants placed in native or grafted bone in irradiated bone in subjects who had received radiation for head and neck cancer. A retrospective chart review was conducted for all patients who received dental implants following radiation treatment for head and neck cancer between May 1, 1987 and July 1, 2008. Only patients irradiated with a radiation dose of 50 Gy or greater and those who received dental implants in the irradiated field after head and neck radiation were included in the study. The associations between implant survival and patient/implant characteristics were estimated by fitting univariate marginal Cox proportional hazards models. A total of 48 patients who had prior head and neck radiation had 271 dental implants placed during May 1987-July 2008. There was no statistically significant difference between implant failure in native and grafted bone (P=0.76). Survival of implants in grafted bone was 82.3% and 98.1% in maxilla and mandible, respectively, after 3 years. Survival of implants in native bone in maxilla and mandible was 79.8% and 100%, respectively, after 3 years. For implants placed in the native bone, there was a higher likelihood of failure in the maxilla compared to the mandible and there was also a tendency for implants placed in the posterior region to fail compared to those placed in the anterior region. There was no significant difference in survival when implants were placed in native or grafted bone in irradiated head and neck cancer patients. For implants placed in native bone, survival was significantly influenced by the location of the implant (maxilla or mandible, anterior or posterior).

A low-frequency versatile wireless power transfer technology for biomedical implants.

PubMed

Jiang, Hao; Zhang, Junmin; Lan, Di; Chao; Liou, Shyshenq; Shahnasser, Hamid; Fechter, Richard; Hirose, Shinjiro; Harrison, Michael; Roy, Shuvo

2013-08-01

Implantable biomedical sensors and actuators are highly desired in modern medicine. In many cases, the implant's electrical power source profoundly determines its overall size and performance . The inductively coupled coil pair operating at the radio-frequency (RF) has been the primary method for wirelessly delivering electrical power to implants for the last three decades . Recent designs significantly improve the power delivery efficiency by optimizing the operating frequency, coil size and coil distance . However, RF radiation hazard and tissue absorption are the concerns in the RF wireless power transfer technology (RF-WPTT) , . Also, it requires an accurate impedance matching network that is sensitive to operating environments between the receiving coil and the load for efficient power delivery . In this paper, a novel low-frequency wireless power transfer technology (LF-WPTT) using rotating rare-earth permanent magnets is demonstrated. The LF-WPTT is able to deliver 2.967 W power at  ∼ 180 Hz to an 117.1 Ω resistor over 1 cm distance with 50% overall efficiency. Because of the low operating frequency, RF radiation hazard and tissue absorption are largely avoided, and the power delivery efficiency from the receiving coil to the load is independent of the operating environment. Also, there is little power loss observed in the LF-WPTT when the receiving coil is enclosed by non-magnetic implant-grade stainless steel.

Phase contrast tomography of the mouse cochlea at microfocus x-ray sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartels, Matthias; Krenkel, Martin; Hernandez, Victor H.

2013-08-19

We present phase contrast x-ray tomography of functional soft tissue within the bony cochlear capsule of mice, carried out at laboratory microfocus sources with well-matched source, detector, geometry, and reconstruction algorithms at spatial resolutions down to 2 μm. Contrast, data quality and resolution enable the visualization of thin membranes and nerve fibers as well as automated segmentation of surrounding bone. By complementing synchrotron radiation imaging techniques, a broad range of biomedical applications becomes possible as demonstrated for optogenetic cochlear implant research.

Radiation Issues Surrounding Very High Energy Ion Implantation

NASA Astrophysics Data System (ADS)

White, Nicholas R.; Tokoro, Nobuhiro; Bell, Edward

2008-11-01

The requirements for doping of semiconductor device layers have pushed the boundaries of implanter energy, for example, with the use of >5 MeV energies for fabrication of optical sensory arrays. With the higher energy comes the need to understand associated radiation risks. This paper presents original measured data quantifying the range in which safe commercial implantation can be accomplished without radiation hazards.

Etude microdosimetrique de l'influence des materiaux sur l'efficacite biologique d'une source d'iode-125

NASA Astrophysics Data System (ADS)

Taschereau, Richard

Cette these concerne les implants permanents pour la prostate. Les isotopes employes, le 103Pd et l'125I, semblent produire les memes resultats cliniques: le premier a cause d'une radiation plus efficace et le second a cause de sa demi-vie plus longue. La recherche utilise le cadre theorique de la microdosimetrie et des simulations Monte Carlo. Elle propose d'employer le spectre d'ejection dans le calcul de l'efficacite; ce changement fait passer l'efficacite relative du 103Pd de 10% a 5%. Elle montre ensuite qu'il est possible d'ameliorer l'efficacite de la radiation de 125I par l'exploitation des rayons X caracteristiques de la capsule. Une source amelioree faite de molybdene et d'yttrium est donnee en exemple. Elle procure une radiation de 5--7% plus efficace, ce qui surclasse les deux sources existantes. Les applications ne se limitent pas au traitement de la prostate; le traitement du melanome oculaire et la curietherapie endovasculaire pourraient en beneficier.

An angle-resolved, wavelength-dispersive x-ray fluorescence spectrometer for depth profile analysis of ion-implanted semiconductors using synchrotron radiation

NASA Astrophysics Data System (ADS)

Schmitt, W.; Hormes, J.; Kuetgens, U.; Gries, W. H.

1992-01-01

An apparatus for angle-resolved, wavelength-dispersive x-ray fluorescence spectroscopy with synchrotron radiation has been built and tested at the beam line BN2 of the Bonn electron stretcher and accelerator (ELSA). The apparatus is to be used for nondestructive depth profile analysis of ion-implanted semiconductors as part of the multinational Versailles Project of Advanced Materials and Standards (VAMAS) project on ion-implanted reference materials. In particular, the centroid depths of depth profiles of various implants is to be determined by use of the angle-resolved signal ratio technique. First results of measurements on implants of phosphorus (100 keV, 1016 cm-2) and sulfur (200 keV, 1014 cm-2) in silicon wafers using ``white'' synchrotron radiation are presented and suggest that it should be generally possible to measure the centroid depth of an implant at dose densities as low as 1014 cm-2. Some of the apparative and technical requirements are discussed which are peculiar to the use of synchrotron radiation in general and to the use of nonmonochromatized radiation in particular.

Dosimetric considerations and early clinical experience of accelerated partial breast irradiation using multi-lumen applicators in the setting of breast augmentation.

PubMed

Akhtari, Mani; Pino, Ramiro; Scarboro, Sarah B; Bass, Barbara L; Miltenburg, Darlene M; Butler, E Brian; Teh, Bin S

2015-12-01

Accelerated partial breast irradiation (APBI) is an accepted treatment option in breast-conserving therapy for early stage breast cancer. However, data regarding outcomes of patients treated with multi-lumen catheter systems who have existing breast implants is limited. The purpose of this study was to report treatment parameters, outcomes, and possible dosimetric correlation with cosmetic outcome for this population of patients at our institution. We report the treatment and outcome of seven consecutive patients with existing breast implants and early stage breast cancer who were treated between 2009 and 2013 using APBI following lumpectomy. All patients were treated twice per day for five days to a total dose of 34 Gy using a high-dose-rate (192)Ir source. Cosmetic outcomes were evaluated using the Harvard breast cosmesis scale, and late toxicities were reported using the Radiation Therapy Oncology Group (RTOG) late radiation morbidity schema. After a mean follow-up of 32 months, all patients have remained cancer free. Six out of seven patients had an excellent or good cosmetic outcome. There were no grade 3 or 4 late toxicities. The average total breast implant volume was 279.3 cc, received an average mean dose of 12.1 Gy, and a maximum dose of 234.1 Gy. The average percentage of breast implant volume receiving 50%, 75%, 100%, 150%, and 200% of the prescribed dose was 15.6%, 7.03%, 4.6%, 1.58%, and 0.46%, respectively. Absolute volume of breast implants receiving more than 50% of prescribed dose correlated with worse cosmetic outcomes. Accelerated partial breast irradiation using a multi-lumen applicator in patients with existing breast implants can safely be performed with promising early clinical results. The presence of the implant did not compromise the ability to achieve dosimetric criteria; however, dose to the implant and the irradiated implant volume may be related with worse cosmetic outcomes.

Dosimetric considerations and early clinical experience of accelerated partial breast irradiation using multi-lumen applicators in the setting of breast augmentation

PubMed Central

Akhtari, Mani; Pino, Ramiro; Scarboro, Sarah B.; Bass, Barbara L.; Miltenburg, Darlene M.; Butler, E. Brian

2015-01-01

Purpose Accelerated partial breast irradiation (APBI) is an accepted treatment option in breast-conserving therapy for early stage breast cancer. However, data regarding outcomes of patients treated with multi-lumen catheter systems who have existing breast implants is limited. The purpose of this study was to report treatment parameters, outcomes, and possible dosimetric correlation with cosmetic outcome for this population of patients at our institution. Material and methods We report the treatment and outcome of seven consecutive patients with existing breast implants and early stage breast cancer who were treated between 2009 and 2013 using APBI following lumpectomy. All patients were treated twice per day for five days to a total dose of 34 Gy using a high-dose-rate 192Ir source. Cosmetic outcomes were evaluated using the Harvard breast cosmesis scale, and late toxicities were reported using the Radiation Therapy Oncology Group (RTOG) late radiation morbidity schema. Results After a mean follow-up of 32 months, all patients have remained cancer free. Six out of seven patients had an excellent or good cosmetic outcome. There were no grade 3 or 4 late toxicities. The average total breast implant volume was 279.3 cc, received an average mean dose of 12.1 Gy, and a maximum dose of 234.1 Gy. The average percentage of breast implant volume receiving 50%, 75%, 100%, 150%, and 200% of the prescribed dose was 15.6%, 7.03%, 4.6%, 1.58%, and 0.46%, respectively. Absolute volume of breast implants receiving more than 50% of prescribed dose correlated with worse cosmetic outcomes. Conclusions Accelerated partial breast irradiation using a multi-lumen applicator in patients with existing breast implants can safely be performed with promising early clinical results. The presence of the implant did not compromise the ability to achieve dosimetric criteria; however, dose to the implant and the irradiated implant volume may be related with worse cosmetic outcomes. PMID:26816499

Does the presence of an implant including expander with internal port alter radiation dose? An ex vivo model.

PubMed

Strang, Barbara; Murphy, Kyla; Seal, Shane; Cin, Arianna Dal

2013-01-01

There is a lack of literature examining the dosimetric implications of irradiating breast implants and expanders with internal ports inserted at the time of mastectomy. To determine whether the presence of breast expanders with port in saline or silicone implants affect the dose uniformity across the breast when irradiated with various photon and electron energies. One tissue-equivalent torso phantom with overlying tissue expanders in saline or silicone implants were irradiated using tangential fields with 6 MV and 18 MV photons and 9 MeV and 12 MeV electrons. All dose measurements were performed using thermoluminescent dosimeters (TLDs). The TLDs were arranged around the port and the perimeters of either the expander, or saline or silicone implant. Comparisons of measured radiation doses, and between the expected and measured doses of radiation from the TLDs on each prosthesis, were performed. Data were analyzed using two-tailed t tests. There were no differences in TLD measurements between the expander and the saline implant for all energy modalities, and for the expected versus actual measurements for the saline implant. Higher than anticipated measurements were recorded for a significant number of TLD positions around the silicone implants. Radiation doses around saline implants or expanders with internal port were unaltered, whereas dose recordings for silicone implants were higher than predicted in the present laboratory/ex vivo study.

Malfunction of cardiac devices after radiotherapy without direct exposure to ionizing radiation: mechanisms and experimental data.

PubMed

Zecchin, Massimo; Morea, Gaetano; Severgnini, Mara; Sergi, Elisabetta; Baratto Roldan, Anna; Bianco, Elisabetta; Magnani, Silvia; De Luca, Antonio; Zorzin Fantasia, Anna; Salvatore, Luca; Milan, Vittorino; Giannini, Gianrossano; Sinagra, Gianfranco

2016-02-01

Malfunctions of cardiac implantable electronical devices (CIED) have been described after high-energy radiation therapy even in the absence of direct exposure to ionizing radiation, due to diffusion of neutrons (n) causing soft errors in inner circuits. The purpose of the study was to analyse the effect of scattered radiation on different types and models of CIED and the possible sources of malfunctions. Fifty-nine explanted CIED were placed on an anthropomorphous phantom of tissue-equivalent material, and a high-energy photon (15 MV) radiotherapy course (total dose = 70 Gy) for prostate treatment was performed. All devices were interrogated before and after radiation. Radiation dose, the electromagnetic field, and neutron fluence at the CIED site were measured. Thirty-four pacemakers (PM) and 25 implantable cardioverter-defibrillators (ICD) were analysed. No malfunctions were detected before radiation. After radiation a software malfunction was evident in 13 (52%) ICD and 6 (18%) PM; no significant electromagnetic field or photon radiations were detected in the thoracic region. Neutron capture was demonstrated by the presence of the (198)Au((197)Au + n) or (192)Ir((191)Ir + n) isotope activation; it was significantly greater in ICD than in PM and non-significantly greater in damaged devices. A greater effect in St Jude PM (2/2 damaged), Boston (9/11), and St Jude ICD (3/6) and in older ICD models was observed; the year of production was not relevant in PM. High-energy radiation can cause different malfunctions on CIED, particularly ICD, even without direct exposure to ionizing radiation due to scattered radiation of neutrons produced by the linear accelerator. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Definition of medical event is to be based on the total source strength for evaluation of permanent prostate brachytherapy: A report from the American Society for Radiation Oncology.

PubMed

Nag, Subir; Demanes, D Jeffrey; Hagan, Michael; Rivard, Mark J; Thomadsen, Bruce R; Welsh, James S; Williamson, Jeffrey F

2011-10-01

The Nuclear Regulatory Commission deems it to be a medical event (ME) if the total dose delivered differs from the prescribed dose by 20% or more. A dose-based definition of ME is not appropriate for permanent prostate brachytherapy as it generates too many spurious MEs and thereby creates unnecessary apprehension in patients, and ties up regulatory bodies and the licensees in unnecessary and burdensome investigations. A more suitable definition of ME is required for permanent prostate brachytherapy. The American Society for Radiation Oncology (ASTRO) formed a working group of experienced clinicians to review the literature, assess the validity of current regulations, and make specific recommendations about the definition of an ME in permanent prostate brachytherapy. The working group found that the current definition of ME in §35.3045 as "the total dose delivered differs from the prescribed dose by 20 percent or more" was not suitable for permanent prostate brachytherapy since the prostate volume (and hence the resultant calculated prostate dose) is dependent on the timing of the imaging, the imaging modality used, the observer variability in prostate contouring, the planning margins used, inadequacies of brachytherapy treatment planning systems to calculate tissue doses, and seed migration within and outside the prostate. If a dose-based definition for permanent implants is applied strictly, many properly executed implants would be improperly classified as an ME leading to a detrimental effect on brachytherapy. The working group found that a source strength-based criterion, of >20% of source strength prescribed in the post-procedure written directive being implanted outside the planning target volume is more appropriate for defining ME in permanent prostate brachytherapy. ASTRO recommends that the definition of ME for permanent prostate brachytherapy should not be dose based but should be based upon the source strength (air-kerma strength) administered.

SU-E-T-570: Management of Radiation Oncology Patients with Cochlear Implant and Other Bionic Devices in the Brain and Head and Neck Regions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, F.Q; Chen, Z; Nath, R

Purpose: To investigate the current status of clinical usage of cochlear implant (CI) and other bionic devices (BD) in the brain and head and neck regions (BH and N) and their management in patients during radiotherapy to ensure patient health and safety as well as optimum radiation delivery. Methods: Literature review was performed with both CIs and radiotherapy and their variants as keywords in PubMed, INSPEC and other sources. The focus was on CIs during radiotherapy, but it also included other BDs in BHȦN, such as auditory brainstem implant, bionic retinal implant, and hearing aids, among others. Results: Interactions betweenmore » CIs and radiation may cause CIs malfunction. The presence of CIs may also cause suboptimum dose distribution if a treatment plan was not well designed. A few studies were performed for the hearing functions of CIs under irradiations of 4 MV and 6 MV x-rays. However, x-rays with higher energies (10 to 18 MV) broadly used in radiotherapy have not been explored. These higher energetic beams are more damaging to electronics due to strong penetrating power and also due to neutrons generated in the treatment process. Modern CIs are designed with more and more complicated integrated circuits, which may be more susceptible to radiation damage and malfunction. Therefore, careful management is important for safety and treatment outcomes. Conclusion: Although AAPM TG-34, TG-63, and TG-203 (update of TG-34, not published yet) reports may be referenced for management of CIs and other BDs in the brain and H and N regions, a site- and device-specified guideline should be developed for CIs and other BDs. Additional evaluation of CI functions under clinically relevant set-ups should also be performed to provide clinicians with better knowledge in clinical decision making.« less

Does the presence of an implant including expander with internal port alter radiation dose? An ex vivo model

PubMed Central

Strang, Barbara; Murphy, Kyla; Seal, Shane; Cin, Arianna Dal

2013-01-01

BACKGROUND: There is a lack of literature examining the dosimetric implications of irradiating breast implants and expanders with internal ports inserted at the time of mastectomy. OBJECTIVE: To determine whether the presence of breast expanders with port in saline or silicone implants affect the dose uniformity across the breast when irradiated with various photon and electron energies. METHODS: One tissue-equivalent torso phantom with overlying tissue expanders in saline or silicone implants were irradiated using tangential fields with 6 MV and 18 MV photons and 9 MeV and 12 MeV electrons. All dose measurements were performed using thermoluminescent dosimeters (TLDs). The TLDs were arranged around the port and the perimeters of either the expander, or saline or silicone implant. Comparisons of measured radiation doses, and between the expected and measured doses of radiation from the TLDs on each prosthesis, were performed. Data were analyzed using two-tailed t tests. RESULTS: There were no differences in TLD measurements between the expander and the saline implant for all energy modalities, and for the expected versus actual measurements for the saline implant. Higher than anticipated measurements were recorded for a significant number of TLD positions around the silicone implants. CONCLUSIONS: Radiation doses around saline implants or expanders with internal port were unaltered, whereas dose recordings for silicone implants were higher than predicted in the present laboratory/ex vivo study. PMID:24431935

Characterization of simple wireless neurostimulators and sensors.

PubMed

Gulick, Daniel W; Towe, Bruce C

2014-01-01

A single diode with a wireless power source and electrodes can act as an implantable stimulator or sensor. We have built such devices using RF and ultrasound power coupling. These simple devices could drastically reduce the size, weight, and cost of implants for applications where efficiency is not critical. However, a shortcoming has been a lack of control: any movement of the external power source would change the power coupling, thereby changing the stimulation current or modulating the sensor response. To correct for changes in power and signal coupling, we propose to use harmonic signals from the device. The diode acts as a frequency multiplier, and the harmonics it emits contain information about the drive level and bias. A simplified model suggests that estimation of power, electrode bias, and electrode resistance is possible from information contained in radiated harmonics even in the presence of significant noise. We also built a simple RF-powered stimulator with an onboard voltage limiter.

Herbert M. Parker: Publications and contributions to radiological and health physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kathren, R.L.; Baalman, R.W.; Bair, W.J.

For more than a half century, Herbert M. Parker was a leading force in radiological physics. As a scientist, he was codeveloper of a systematic dosimetry scheme for implant therapy and the innovative proposer of radiological units with unambiguous physical and biological bases. He made seminal contributions to the development of scientifically based radiation protection standards and, as an administrator and manager as well as scientist, helped the Hanford Laboratories to achieve preeminance in several areas, including radiation biology, radioactive waste disposal, and environmental radioactivity. This volume brings together, sometimes from obscure sources, his works.

Radiation Damage Formation And Annealing In Mg-Implanted GaN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whelan, Sean; Kelly, Michael J.; Yan, John

2005-06-30

We have implanted GaN with Mg ions over an energy range of 200keV to 1MeV at substrate temperatures of -150 (cold) and +300 deg. C (hot). The radiation damage formation in GaN was increased for cold implants when compared to samples implanted at elevated temperatures. The increase in damage formation is due to a reduction in the dynamic defect annealing during ion irradiation. The dopant stopping in the solid also depends upon the implant temperature. For a fixed implant energy and dose, Mg ions have a shorter range in GaN for cold implants when compared to hot implants which ismore » caused by the increase in scattering centres (disorder)« less

Positron and nanoindentation study of helium implanted high chromium ODS steels

NASA Astrophysics Data System (ADS)

Veternikova, Jana Simeg; Fides, Martin; Degmova, Jarmila; Sojak, Stanislav; Petriska, Martin; Slugen, Vladimir

2017-12-01

Three oxide dispersion strengthened (ODS) steels with different chromium content (MA 956, MA 957 and ODM 751) were studied as candidate materials for new nuclear reactors in term of their radiation stability. The radiation damage was experimentally simulated by helium ion implantation with energy of ions up to 500 keV. The study was focused on surface and sub-surface structural change due to the ion implantation observed by mostly non-destructive techniques: positron annihilation lifetime spectroscopy and nanoindentation. The applied techniques demonstrated the best radiation stability of the steel ODM 751. Blistering effect occurred due to high implantation dose (mostly in MA 956) was studied in details.

Impact of new X-ray technology on patient dose in pacemaker and implantable cardioverter defibrillator (ICD) implantations.

PubMed

van Dijk, Joris D; Ottervanger, Jan Paul; Delnoy, Peter Paul H M; Lagerweij, Martine C M; Knollema, Siert; Slump, Cornelis H; Jager, Pieter L

2017-01-01

New X-ray technology providing new image processing techniques may reduce radiation exposure. The aim of this study was to quantify this radiation exposure reduction for patients during pacemaker and implantable cardioverter defibrillator (ICD) implantation. In this retrospective study, 1185 consecutive patients who had undergone de novo pacemaker or ICD implantation during a 2-year period were included. All implantations in the first year were performed using the reference technology (Allura Xper), whereas in the second year, the new X-ray technology (AlluraClarity) was used. Radiation exposure, expressed as the dose area product (DAP), was compared between the two time periods to determine the radiation exposure reduction for pacemaker and ICD implantations without cardiac resynchronization therapy (CRT) and with CRT. Procedure duration and contrast volume were used as measures to compare complexity and image quality. The study population consisted of 591 patients who had undergone an implantation using the reference technology, and 594 patients with the new X-ray technology. The two groups did not differ in age, gender, or body mass index. The DAP decreased with 69 % from 16.4 ± 18.5 to 5.2 ± 6.6 Gy cm 2 for the non-CRT implantations (p < 0.001). The DAP decreased with 75 % from 72.1 ± 60.0 to 17.8 ± 17.4 Gy cm 2 for the CRT implantations (p < 0.001). Nevertheless, procedure duration and contrast volume did not differ when using the new technology (p = 0.09 and p = 0.20, respectively). Introduction of new X-ray technology resulted in a radiation exposure reduction of more than 69 % for patients during pacemaker and ICD implantation while image quality was unaffected.

Effects of estrogen and gender on cataractogenesis induced by high-LET radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, M.A.; Rusek, A.; Valluri, S.

2010-02-01

Planning for long-duration manned lunar and interplanetary missions requires an understanding of radiation-induced cataractogenesis. Previously, it was demonstrated that low-linear energy transfer (LET) irradiation with 10 Gy of {sup 60}Co {gamma} rays resulted in an increased incidence of cataracts in male rats compared to female rats. This gender difference was not due to differences in estrogen, since male rats treated with the major secreted estrogen 17-{beta}-estradiol (E2) showed an identical increase compared to untreated males. We now compare the incidence and rate of progression of cataracts induced by high-LET radiation in male and female Sprague-Dawley rats. Rats received a singlemore » dose of 1 Gy of 600 MeV {sup 56}Fe ions. Lens opacification was measured at 2-4 week intervals with a slit lamp. The incidence and rate of progression of radiation-induced cataracts was significantly increased in the animals in which estrogen was available from endogenous or exogenous sources. Male rats with E2 capsules implanted had significantly higher rates of progression compared to male rats with empty capsules implanted (P = 0.025) but not compared to the intact female rats. These results contrast with data obtained after low-LET irradiation and suggest the possibility that the different types of damage caused by high- and low-LET radiation may be influenced differentially by steroid sex hormones.« less

Assessment of the Survival of Dental Implants in Irradiated Jaws Following Treatment of Oral Cancer: A Retrospective Study

PubMed Central

Rana, Meenakshi Chauhan; Solanki, Swati; Pujari, Sudarshan C; Shaw, Eisha; Sharma, Swati; Anand, Abhishek; Singh, Harkanwal Preet

2016-01-01

Background: In patients undergoing head and neck surgery for various pathologic conditions, implants are one of the best restorative options and are increasing widely used. Therefore, we evaluated the success of dental implants in the irradiated jaws of patients following treatment of oral cancer oral cancer treated patients. Materials and Methods: Data of oral cancer treated patients was collected retrospectively from 2002 to 2008. We took 46 oral cancer treated patients in which implants were placed in irradiated jaws for rehabilitation. Results: It was found that out of 162 dental implants placed, 52 failed. Furthermore, there was no variation in the implant survival rate in between both the jaws. Radiation dose of <50 Gy units also showed significantly increased amount of implant survival rate. Conclusions: Implant survival is multifactorial and depends upon a number of factors like level of radiation exposure in that area, time gap between last radiation doses etc., Further research is required in this field to improve the esthetics and quality of life of cancer treated patients. PMID:27843270

3D silicone rubber interfaces for individually tailored implants.

PubMed

Stieghorst, Jan; Bondarenkova, Alexandra; Burblies, Niklas; Behrens, Peter; Doll, Theodor

2015-01-01

For the fabrication of customized silicone rubber based implants, e.g. cochlear implants or electrocortical grid arrays, it is required to develop high speed curing systems, which vulcanize the silicone rubber before it runs due to a heating related viscosity drop. Therefore, we present an infrared radiation based cross-linking approach for the 3D-printing of silicone rubber bulk and carbon nanotube based silicone rubber electrode materials. Composite materials were cured in less than 120 s and material interfaces were evaluated with scanning electron microscopy. Furthermore, curing related changes in the mechanical and cell-biological behaviour were investigated with tensile and WST-1 cell biocompatibility tests. The infrared absorption properties of the silicone rubber materials were analysed with fourier transform infrared spectroscopy in transmission and attenuated total reflection mode. The heat flux was calculated by using the FTIR data, emissivity data from the infrared source manufacturer and the geometrical view factor of the system.

Optical path of infrared neural stimulation in the guinea pig and cat cochlea

NASA Astrophysics Data System (ADS)

Rajguru, Suhrud M.; Hwang, Margaret; Moreno, Laura E.; Matic, Agnella I.; Stock, Stuart R.; Richter, Claus-Peter

2011-03-01

It has been demonstrated previously that infrared neural stimulation (INS) can be used to stimulate spiral ganglion cells in the cochlea. With INS, neural stimulation can be achieved without direct contact of the radiation source and the tissue and is spatially well resolved. The presence of fluids or bone between the target structure and the radiation source may lead to absorption or scattering of the radiation and limit the efficacy of INS. To develop INS based cochlear implants, it is critical to determine the beam path of the radiation in the cochlea. In the present study, we utilized noninvasive X-ray microtomography (microCT) to visualize the orientation and location of the optical fiber within the guinea pig and cat cochlea. Overall, the results indicated that the optical fiber was directed towards the spiral ganglion cells in the cochlea and not the nerve fibers in the center of the modiolus. The fiber was approximately 300 μm away from the target structures. In future studies, results from the microCT will be correlated with physiology obtained from recordings in the midbrain.

Plastic optical fibre sensor for in-vivo radiation monitoring during brachytherapy

NASA Astrophysics Data System (ADS)

Woulfe, P.; Sullivan, F. J.; Lewis, E.; O'Keeffe, S.

2015-09-01

An optical fibre sensor is presented for applications in real-time in-vivo monitoring of the radiation dose a cancer patient receives during seed implantation in Brachytherapy. The sensor is based on radioluminescence whereby radiation sensitive scintillation material is embedded in the core of a 1mm plastic optical fibre. Three scintillation materials are investigated: thallium-doped caesium iodide (CsI:Tl), terbium-doped gadolinium oxysulphide (Gd2O2S:Tb) and europium-doped lanthanum oxysulphide (La2O2S:Eu). Terbium-doped gadolinium oxysulphide was identified as being the most suitable scintillator and further testing demonstrates its measureable response to different activities of Iodine-125, the radio-active source commonly used in Brachytherapy for treating prostate cancer.

Effect of reversal of double-implantation schedule of boron in mercury cadmium telluride

NASA Astrophysics Data System (ADS)

Kumar, Rakesh; Dutt, M. B.; Nath, R.; Gopal, Vishnu; Khosla, Y. P.; Sharma, K. K.

1992-02-01

Radiation damage due to B+ ion implantation in p-type HgCdTe has been found to create Hg interstitials giving rise to n-type conversion. The implantation energies were kept at 50 and 100 keV with a dose of 1 X 1013 cm-2 each. The effect of implantation with ascending and descending orders of energies were found to be quite different from each other. Radiation enhanced diffusion is thought to be responsible for this anomaly.

[Electromagnetic interference in the current era of cardiac implantable electronic devices designed for magnetic resonance environment].

PubMed

Ribatti, Valentina; Santini, Luca; Forleo, Giovanni B; Della Rocca, Domenico; Panattoni, Germana; Scali, Marta; Schirripa, Valentina; Danisi, Nicola; Ammirati, Fabrizio; Santini, Massimo

2017-04-01

In the last decades we are observing a continuous increase in the number of patients wearing cardiac implantable electronic devices (CIEDs). At the same time, we face daily with a domestic and public environment featured more and more by the presence and the utilization of new emitters and finally, more medical procedures are based on electromagnetic fields as well. Therefore, the topic of the interaction of devices with electromagnetic interference (EMI) is increasingly a real and actual problem.In the medical environment most attention is paid to magnetic resonance, nevertheless the risk of interaction is present also with ionizing radiation, electrical nerve stimulation and electrosurgery. In the non-medical environment, most studies reported in the literature focused on mobile phones, metal detectors, as well as on headphones or digital players as potential EMI sources, but many other instruments and tools may be intentional or non-intentional sources of electromagnetic fields.CIED manufacturers are more and more focusing on new technological features in order to make implantable devices less susceptible to EMI. However, patients and emitter manufacturers should be aware that limitations exist and that there is not complete immunity to EMI.

The Simulation of the Recharging Method Based on Solar Radiation for an Implantable Biosensor.

PubMed

Li, Yun; Song, Yong; Kong, Xianyue; Li, Maoyuan; Zhao, Yufei; Hao, Qun; Gao, Tianxin

2016-09-10

A method of recharging implantable biosensors based on solar radiation is proposed. Firstly, the models of the proposed method are developed. Secondly, the recharging processes based on solar radiation are simulated using Monte Carlo (MC) method and the energy distributions of sunlight within the different layers of human skin have been achieved and discussed. Finally, the simulation results are verified experimentally, which indicates that the proposed method will contribute to achieve a low-cost, convenient and safe method for recharging implantable biosensors.

The Simulation of the Recharging Method Based on Solar Radiation for an Implantable Biosensor

PubMed Central

Li, Yun; Song, Yong; Kong, Xianyue; Li, Maoyuan; Zhao, Yufei; Hao, Qun; Gao, Tianxin

2016-01-01

A method of recharging implantable biosensors based on solar radiation is proposed. Firstly, the models of the proposed method are developed. Secondly, the recharging processes based on solar radiation are simulated using Monte Carlo (MC) method and the energy distributions of sunlight within the different layers of human skin have been achieved and discussed. Finally, the simulation results are verified experimentally, which indicates that the proposed method will contribute to achieve a low-cost, convenient and safe method for recharging implantable biosensors. PMID:27626422

Ion implantation reduces radiation sensitivity of metal oxide silicon /MOS/ devices

NASA Technical Reports Server (NTRS)

1971-01-01

Implanting nitrogen ions improves hardening of silicon oxides 30 percent to 60 percent against ionizing radiation effects. Process reduces sensitivity, but retains stability normally shown by interfaces between silicon and thermally grown oxides.

Design and optimization of a brachytherapy robot

NASA Astrophysics Data System (ADS)

Meltsner, Michael A.

Trans-rectal ultrasound guided (TRUS) low dose rate (LDR) interstitial brachytherapy has become a popular procedure for the treatment of prostate cancer, the most common type of non-skin cancer among men. The current TRUS technique of LDR implantation may result in less than ideal coverage of the tumor with increased risk of negative response such as rectal toxicity and urinary retention. This technique is limited by the skill of the physician performing the implant, the accuracy of needle localization, and the inherent weaknesses of the procedure itself. The treatment may require 100 or more sources and 25 needles, compounding the inaccuracy of the needle localization procedure. A robot designed for prostate brachytherapy may increase the accuracy of needle placement while minimizing the effect of physician technique in the TRUS procedure. Furthermore, a robot may improve associated toxicities by utilizing angled insertions and freeing implantations from constraints applied by the 0.5 cm-spaced template used in the TRUS method. Within our group, Lin et al. have designed a new type of LDR source. The "directional" source is a seed designed to be partially shielded. Thus, a directional, or anisotropic, source does not emit radiation in all directions. The source can be oriented to irradiate cancerous tissues while sparing normal ones. This type of source necessitates a new, highly accurate method for localization in 6 degrees of freedom. A robot is the best way to accomplish this task accurately. The following presentation of work describes the invention and optimization of a new prostate brachytherapy robot that fulfills these goals. Furthermore, some research has been dedicated to the use of the robot to perform needle insertion tasks (brachytherapy, biopsy, RF ablation, etc.) in nearly any other soft tissue in the body. This can be accomplished with the robot combined with automatic, magnetic tracking.

Mechanical stresses and amorphization of ion-implanted diamond

NASA Astrophysics Data System (ADS)

Khmelnitsky, R. A.; Dravin, V. A.; Tal, A. A.; Latushko, M. I.; Khomich, A. A.; Khomich, A. V.; Trushin, A. S.; Alekseev, A. A.; Terentiev, S. A.

2013-06-01

Scanning white light interferometry and Raman spectroscopy were used to investigate the mechanical stresses and structural changes in ion-implanted natural diamonds with different impurity content. The uniform distribution of radiation defects in implanted area was obtained by the regime of multiple-energy implantation of keV He+ ions. A modification of Bosia's et al. (Nucl. Instrum. Meth. B 268 (2010) 2991) method for determining the internal stresses and the density variation in an ion-implanted diamond layer was proposed that suggests measuring, in addition to the surface swelling of a diamond plate, the radius of curvature of the plate. It is shown that, under multiple-energy implantation of He+, mechanical stresses in the implanted layer may be as high as 12 GPa. It is shown that radiation damage reaches saturation for the implantation fluence characteristic of amorphization of diamond but is appreciably lower than the graphitization threshold.

Evaluation of a Proposed Biodegradable 188Re Source for Brachytherapy Application

PubMed Central

Khorshidi, Abdollah; Ahmadinejad, Marjan; Hamed Hosseini, S.

2015-01-01

Abstract This study aimed to evaluate dosimetric characteristics based on Monte Carlo (MC) simulations for a proposed beta emitter bioglass 188Re seed for internal radiotherapy applications. The bioactive glass seed has been developed using the sol-gel technique. The simulations were performed for the seed using MC radiation transport code to investigate the dosimetric factors recommended by the AAPM Task Group 60 (TG-60). Dose distributions due to the beta and photon radiation were predicted at different radial distances surrounding the source. The dose rate in water at the reference point was calculated to be 7.43 ± 0.5 cGy/h/μCi. The dosimetric factors consisting of the reference point dose rate, D(r0,θ0), the radial dose function, g(r), the 2-dimensional anisotropy function, F(r,θ), the 1-dimensional anisotropy function, φan(r), and the R90 quantity were estimated and compared with several available beta-emitting sources. The element 188Re incorporated in bioactive glasses produced by the sol-gel technique provides a suitable solution for producing new materials for seed implants applied to brachytherapy applications in prostate and liver cancers treatment. Dose distribution of 188Re seed was greater isotropic than other commercially attainable encapsulated seeds, since it has no end weld to attenuate radiation. The beta radiation-emitting 188Re source provides high doses of local radiation to the tumor tissue and the short range of the beta particles limit damage to the adjacent normal tissue. PMID:26181543

Effect of Brain Tumor Presence During Radiation on Tissue Toxicity: Transcriptomic and Metabolic Changes.

PubMed

Zawaski, Janice A; Sabek, Omaima M; Voicu, Horatiu; Eastwood Leung, Hon-Chiu; Gaber, M Waleed

2017-11-15

Radiation therapy (RT) causes functional and transcriptomic changes in the brain; however, most studies have been carried out in normal rodent brains. Here, the long-term effect of irradiation and tumor presence during radiation was investigated. Male Wistar rats ∼7 weeks old were divided into 3 groups: sham implant, RT+sham implant, and RT+tumor implant (C6 glioma). Hypofractionated irradiation (8 or 6 Gy/day for 5 days) was localized to a 1-cm strip of cranium starting 5 days after implantation, resulting in complete tumor regression and prolonged survival. Biopsy of tissue was performed in the implant area 65 days after implantation. RNA was hybridized to GeneChip Rat Exon 1.0 ST array. Data were analyzed using significant analysis of microarrays and ingenuity pathway analysis. 1 H magnetic resonance spectroscopy ( 1 H-MRS) imaging was performed in the implantation site 65 to 70 days after implantation using a 9.4 T Biospec magnetic resonance imaging scanner with a quadrature rat brain array. Immunohistochemical staining for astrogliosis, HMG-CoA synthase 2, γ-aminobutyric acid (GABA) and taurine was performed at ∼65 days after implantation. Eighty-four genes had a false discovery rate <3.5%. We compared RT+tumor implant with RT+sham implant animals. The tumor presence affected networks associated with cancer/cell morphology/tissue morphology. 1 H-MRS showed significant reduction in taurine levels (P<.04) at the implantation site in both groups. However, the RT+tumor group also showed significant increase in levels of neurotransmitter GABA (P=.02). Hippocampal taurine levels were only significantly reduced in the RT+tumor group (P=.03). HMG-CoA synthase 2, GABA and taurine levels were confirmed using staining. Glial fibrillary acidic protein staining demonstrated a significant increase in inflammation that was heightened in the RT+tumor group. Our data indicate that tumor presence during radiation significantly affects long-term functional transcriptomics landscape and neurotransmitter levels at the tumor implantation site/normal tissue, accompanied by increased inflammation (astrogliosis). Copyright © 2017 Elsevier Inc. All rights reserved.

Metal artifacts in computed tomography for radiation therapy planning: dosimetric effects and impact of metal artifact reduction.

PubMed

Giantsoudi, Drosoula; De Man, Bruno; Verburg, Joost; Trofimov, Alexei; Jin, Yannan; Wang, Ge; Gjesteby, Lars; Paganetti, Harald

2017-04-21

A significant and increasing number of patients receiving radiation therapy present with metal objects close to, or even within, the treatment area, resulting in artifacts in computed tomography (CT) imaging, which is the most commonly used imaging method for treatment planning in radiation therapy. In the presence of metal implants, such as dental fillings in treatment of head-and-neck tumors, spinal stabilization implants in spinal or paraspinal treatment or hip replacements in prostate cancer treatments, the extreme photon absorption by the metal object leads to prominent image artifacts. Although current CT scanners include a series of correction steps for beam hardening, scattered radiation and noisy measurements, when metal implants exist within or close to the treatment area, these corrections do not suffice. CT metal artifacts affect negatively the treatment planning of radiation therapy either by causing difficulties to delineate the target volume or by reducing the dose calculation accuracy. Various metal artifact reduction (MAR) methods have been explored in terms of improvement of organ delineation and dose calculation in radiation therapy treatment planning, depending on the type of radiation treatment and location of the metal implant and treatment site. Including a brief description of the available CT MAR methods that have been applied in radiation therapy, this article attempts to provide a comprehensive review on the dosimetric effect of the presence of CT metal artifacts in treatment planning, as reported in the literature, and the potential improvement suggested by different MAR approaches. The impact of artifacts on the treatment planning and delivery accuracy is discussed in the context of different modalities, such as photon external beam, brachytherapy and particle therapy, as well as by type and location of metal implants.

Metal artifacts in computed tomography for radiation therapy planning: dosimetric effects and impact of metal artifact reduction

NASA Astrophysics Data System (ADS)

Giantsoudi, Drosoula; De Man, Bruno; Verburg, Joost; Trofimov, Alexei; Jin, Yannan; Wang, Ge; Gjesteby, Lars; Paganetti, Harald

2017-04-01

A significant and increasing number of patients receiving radiation therapy present with metal objects close to, or even within, the treatment area, resulting in artifacts in computed tomography (CT) imaging, which is the most commonly used imaging method for treatment planning in radiation therapy. In the presence of metal implants, such as dental fillings in treatment of head-and-neck tumors, spinal stabilization implants in spinal or paraspinal treatment or hip replacements in prostate cancer treatments, the extreme photon absorption by the metal object leads to prominent image artifacts. Although current CT scanners include a series of correction steps for beam hardening, scattered radiation and noisy measurements, when metal implants exist within or close to the treatment area, these corrections do not suffice. CT metal artifacts affect negatively the treatment planning of radiation therapy either by causing difficulties to delineate the target volume or by reducing the dose calculation accuracy. Various metal artifact reduction (MAR) methods have been explored in terms of improvement of organ delineation and dose calculation in radiation therapy treatment planning, depending on the type of radiation treatment and location of the metal implant and treatment site. Including a brief description of the available CT MAR methods that have been applied in radiation therapy, this article attempts to provide a comprehensive review on the dosimetric effect of the presence of CT metal artifacts in treatment planning, as reported in the literature, and the potential improvement suggested by different MAR approaches. The impact of artifacts on the treatment planning and delivery accuracy is discussed in the context of different modalities, such as photon external beam, brachytherapy and particle therapy, as well as by type and location of metal implants.

Favorable toxicity and biochemical control using real-time inverse optimization technique for prostate brachytherapy.

PubMed

Raben, Adam; Rusthoven, Kyle E; Sarkar, Abrihup; Glick, Andrew; Benge, Bruce; Jacobs, Dayee; Raben, David

2009-01-01

Favorable dosimetric results have been reported using intraoperative inverse optimization (IO) for permanent prostate brachytherapy. The clinical implications of these improvements in dosimetry are unclear. We review toxicity and early biochemical outcomes for patients implanted using IO technique. Between 2001 and 2007, 165 patients received permanent prostate implants using real-time IO and had >/=3 months of followup. Dose constraints for inverse planning were: the prostate volume receiving 100% of the prescription dose [prostate V(100)] was >95%; the dose received by 90% of the gland [prostate D(90)] was within the 140-180 by dose range; the volume of urethra receiving 150% of the prescription dose [urethra V(150)] was <30%; and the volume of rectal wall receiving 110% of the prescription dose [rectal V(110)] was <1.0 cc. Toxicity was prospectively scored using the Radiation Therapy Oncology Group toxicity scale and the International Prostate Symptom Score questionnaire. Biochemical control was determined using the nadir + 2 ng/mL definition. Mean followup was 30 months (range, 6-63 months). Risk classification was low risk in 89% and intermediate risk in 11%. Iodine-125 sources were used for 161 implants and palladium-103 sources for four implants. The median number of seeds and total activity implanted were 61 and 999 MBq, respectively, for a median prostate volume of 33.6 cc. Late GU and GI morbidity was uncommon. Among patients with at least 24 months followup, 16% had persistent Grade 2-3 urinary morbidity. Grade 2 rectal bleeding occurred in 1 patient (0.6%). Biochemical failure has occurred in only 4 patients at last followup. IO technique for prostate brachytherapy is associated with low rates of late morbidity and excellent early biochemical control. Additionally, the number of seeds and total implanted activity required to achieve a high-quality implant are lower compared with historical controls.

Developing A Directional High-Dose Rate (d-HDR) Brachytherapy Source

NASA Astrophysics Data System (ADS)

Heredia, Athena Yvonne

Conventional sources used in brachytherapy provide nearly isotropic or radially symmetric dose distributions. Optimizations of dose distributions have been limited to varied dwell times at specified locations within a given treatment volume, or manipulations in source position for seed implantation techniques. In years past, intensity modulated brachytherapy (IMBT) has been used to reduce the amount of radiation to surrounding sensitive structures in select intracavitary cases by adding space or partial shields. Previous work done by Lin et al., at the University of Wisconsin-Madison, has shown potential improvements in conformality for brachytherapy treatments using a directionally shielded low dose rate (LDR) source for treatments in breast and prostate. Directional brachytherapy sources irradiate approximately half of the radial angles around the source, and adequately shield a quarter of the radial angles on the opposite side, with sharp gradient zones between the treated half and shielded quarter. With internally shielded sources, the radiation can be preferentially emitted in such a way as to reduce toxicities in surrounding critical organs. The objective of this work is to present findings obtained in the development of a new directional high dose rate (d-HDR) source. To this goal, 103Pd (Z = 46) is reintroduced as a potential radionuclide for use in HDR brachytherapy. 103Pd has a low average photon energy (21 keV) and relatively short half -life (17 days), which is why it has historically been used in low dose rate applications and implantation techniques. Pd-103 has a carrier-free specific activity of 75000 Ci/g. Using cyclotron produced 103Pd, near carrier-free specific activities can be achieved, providing suitability for high dose rate applications. The evolution of the d-HDR source using Monte Carlo simulations is presented, along with dosimetric parameters used to fully characterize the source. In addition, a discussion on how to obtain elemental palladium, Pd(0), will be discussed in detail. Directional HDR has the potential to improve upon current treatments, providing better dose conformality to the target volume, while maintaining the benefits of HDR applications.

Goserelin Implant

MedlinePlus

Goserelin implant is used in combination with radiation therapy and other medications to treat localized prostate cancer ... and other symptoms) and to help with the treatment of abnormal bleeding of the uterus. Goserelin implant ...

Dual-modal photoacoustic and ultrasound imaging of dental implants

NASA Astrophysics Data System (ADS)

Lee, Donghyun; Park, Sungjo; Kim, Chulhong

2018-02-01

Dental implants are common method to replace decayed or broken tooth. As the implant treatment procedures varies according to the patients' jawbone, bone ridge, and sinus structure, appropriate examinations are necessary for successful treatment. Currently, radiographic examinations including periapical radiology, panoramic X-ray, and computed tomography are commonly used for diagnosing and monitoring. However, these radiographic examinations have limitations in that patients and operators are exposed to radioactivity and multiple examinations are performed during the treatment. In this study, we demonstrated photoacoustic (PA) and ultrasound (US) combined imaging of dental implant that can lower the total amount of absorbed radiation dose in dental implant treatment. An acoustic resolution PA macroscopy and a clinical PA/US system was used for dental implant imaging. The acquired dual modal PA/US imaging results support that the proposed photoacoustic imaging strategy can reduce the radiation dose rate during dental implant treatment.

Compact Radiative Control Structures for Millimeter Astronomy

NASA Technical Reports Server (NTRS)

Brown, Ari D.; Chuss, David T.; Chervenak, James A.; Henry, Ross M.; Moseley, s. Harvey; Wollack, Edward J.

2010-01-01

We have designed, fabricated, and tested compact radiative control structures, including antireflection coatings and resonant absorbers, for millimeter through submillimeter wave astronomy. The antireflection coatings consist of micromachined single crystal silicon dielectric sub-wavelength honeycombs. The effective dielectric constant of the structures is set by the honeycomb cell geometry. The resonant absorbers consist of pieces of solid single crystal silicon substrate and thin phosphorus implanted regions whose sheet resistance is tailored to maximize absorption by the structure. We present an implantation model that can be used to predict the ion energy and dose required for obtaining a target implant layer sheet resistance. A neutral density filter, a hybrid of a silicon dielectric honeycomb with an implanted region, has also been fabricated with this basic approach. These radiative control structures are scalable and compatible for use large focal plane detector arrays.

The difference of scoring dose to water or tissues in Monte Carlo dose calculations for low energy brachytherapy photon sources.

PubMed

Landry, Guillaume; Reniers, Brigitte; Pignol, Jean-Philippe; Beaulieu, Luc; Verhaegen, Frank

2011-03-01

The goal of this work is to compare D(m,m) (radiation transported in medium; dose scored in medium) and D(w,m) (radiation transported in medium; dose scored in water) obtained from Monte Carlo (MC) simulations for a subset of human tissues of interest in low energy photon brachytherapy. Using low dose rate seeds and an electronic brachytherapy source (EBS), the authors quantify the large cavity theory conversion factors required. The authors also assess whether ap plying large cavity theory utilizing the sources' initial photon spectra and average photon energy induces errors related to spatial spectral variations. First, ideal spherical geometries were investigated, followed by clinical brachytherapy LDR seed implants for breast and prostate cancer patients. Two types of dose calculations are performed with the GEANT4 MC code. (1) For several human tissues, dose profiles are obtained in spherical geometries centered on four types of low energy brachytherapy sources: 125I, 103Pd, and 131Cs seeds, as well as an EBS operating at 50 kV. Ratios of D(w,m) over D(m,m) are evaluated in the 0-6 cm range. In addition to mean tissue composition, compositions corresponding to one standard deviation from the mean are also studied. (2) Four clinical breast (using 103Pd) and prostate (using 125I) brachytherapy seed implants are considered. MC dose calculations are performed based on postimplant CT scans using prostate and breast tissue compositions. PTV D90 values are compared for D(w,m) and D(m,m). (1) Differences (D(w,m)/D(m,m)-1) of -3% to 70% are observed for the investigated tissues. For a given tissue, D(w,m)/D(m,m) is similar for all sources within 4% and does not vary more than 2% with distance due to very moderate spectral shifts. Variations of tissue composition about the assumed mean composition influence the conversion factors up to 38%. (2) The ratio of D90(w,m) over D90(m,m) for clinical implants matches D(w,m)/D(m,m) at 1 cm from the single point sources, Given the small variation with distance, using conversion factors based on the emitted photon spectrum (or its mean energy) of a given source introduces minimal error. The large differences observed between scoring schemes underline the need for guidelines on choice of media for dose reporting. Providing such guidelines is beyond the scope of this work.

Fast GPU-based Monte Carlo simulations for LDR prostate brachytherapy.

PubMed

Bonenfant, Éric; Magnoux, Vincent; Hissoiny, Sami; Ozell, Benoît; Beaulieu, Luc; Després, Philippe

2015-07-07

The aim of this study was to evaluate the potential of bGPUMCD, a Monte Carlo algorithm executed on Graphics Processing Units (GPUs), for fast dose calculations in permanent prostate implant dosimetry. It also aimed to validate a low dose rate brachytherapy source in terms of TG-43 metrics and to use this source to compute dose distributions for permanent prostate implant in very short times. The physics of bGPUMCD was reviewed and extended to include Rayleigh scattering and fluorescence from photoelectric interactions for all materials involved. The radial and anisotropy functions were obtained for the Nucletron SelectSeed in TG-43 conditions. These functions were compared to those found in the MD Anderson Imaging and Radiation Oncology Core brachytherapy source registry which are considered the TG-43 reference values. After appropriate calibration of the source, permanent prostate implant dose distributions were calculated for four patients and compared to an already validated Geant4 algorithm. The radial function calculated from bGPUMCD showed excellent agreement (differences within 1.3%) with TG-43 accepted values. The anisotropy functions at r = 1 cm and r = 4 cm were within 2% of TG-43 values for angles over 17.5°. For permanent prostate implants, Monte Carlo-based dose distributions with a statistical uncertainty of 1% or less for the target volume were obtained in 30 s or less for 1 × 1 × 1 mm(3) calculation grids. Dosimetric indices were very similar (within 2.7%) to those obtained with a validated, independent Monte Carlo code (Geant4) performing the calculations for the same cases in a much longer time (tens of minutes to more than a hour). bGPUMCD is a promising code that lets envision the use of Monte Carlo techniques in a clinical environment, with sub-minute execution times on a standard workstation. Future work will explore the use of this code with an inverse planning method to provide a complete Monte Carlo-based planning solution.

Fast GPU-based Monte Carlo simulations for LDR prostate brachytherapy

NASA Astrophysics Data System (ADS)

Bonenfant, Éric; Magnoux, Vincent; Hissoiny, Sami; Ozell, Benoît; Beaulieu, Luc; Després, Philippe

2015-07-01

The aim of this study was to evaluate the potential of bGPUMCD, a Monte Carlo algorithm executed on Graphics Processing Units (GPUs), for fast dose calculations in permanent prostate implant dosimetry. It also aimed to validate a low dose rate brachytherapy source in terms of TG-43 metrics and to use this source to compute dose distributions for permanent prostate implant in very short times. The physics of bGPUMCD was reviewed and extended to include Rayleigh scattering and fluorescence from photoelectric interactions for all materials involved. The radial and anisotropy functions were obtained for the Nucletron SelectSeed in TG-43 conditions. These functions were compared to those found in the MD Anderson Imaging and Radiation Oncology Core brachytherapy source registry which are considered the TG-43 reference values. After appropriate calibration of the source, permanent prostate implant dose distributions were calculated for four patients and compared to an already validated Geant4 algorithm. The radial function calculated from bGPUMCD showed excellent agreement (differences within 1.3%) with TG-43 accepted values. The anisotropy functions at r = 1 cm and r = 4 cm were within 2% of TG-43 values for angles over 17.5°. For permanent prostate implants, Monte Carlo-based dose distributions with a statistical uncertainty of 1% or less for the target volume were obtained in 30 s or less for 1 × 1 × 1 mm3 calculation grids. Dosimetric indices were very similar (within 2.7%) to those obtained with a validated, independent Monte Carlo code (Geant4) performing the calculations for the same cases in a much longer time (tens of minutes to more than a hour). bGPUMCD is a promising code that lets envision the use of Monte Carlo techniques in a clinical environment, with sub-minute execution times on a standard workstation. Future work will explore the use of this code with an inverse planning method to provide a complete Monte Carlo-based planning solution.

Variation of mechanical properties and oxidation with radiation dose and source in highly crosslinked remelted UHMWPE.

PubMed

Fung, Mitchell; Bowsher, John G; Van Citters, Douglas W

2018-06-01

Ultra-high molecular weight polyethylene (UHMWPE) is the current gold standard for bearing materials used in total joint arthroplasty. High-dose radiation is commonly used to crosslink UHMWPE, thereby improving its wear resistance. A subsequent remelting step eliminates trapped residual free radicals to promote oxidative stability on the shelf, and to prevent material degradation over the long term. Assessment of clinically retrieved, highly crosslinked UHMWPE devices shows signs of unanticipated oxidation occurring in vivo, despite the absence of free radicals prior to implantation. These findings warrant further investigation into possible factors impacting this phenomenon along with its clinical implications. The overall objective of this work is to quantify the influence of irradiation dose and source on UHMWPE's oxidative stability, along with the effects of oxidation on the ultimate mechanical properties, including strength, ductility, and toughness. The results showed a strong positive correlation between maximum oxidation and initial transvinylene content. Critical oxidation levels in the context of mechanical property loss were determined for e-beam and gamma treatments at various radiation doses. Further, it was shown that critical oxidation was more dependent on radiation dose and less dependent on source. If in vivo oxidation persists in these devices, this can potentially lead to mechanical failure (e.g. fatigue damage) as observed in terminally gamma-sterilized devices. Copyright © 2018 Elsevier Ltd. All rights reserved.

A new tritium monitor design based on plasma source ion implantation technique

NASA Astrophysics Data System (ADS)

Nassar, Rafat Mohammad

Tritium is an important isotope of hydrogen. The availability of tritium in our environment is manifest through both natural and artificial sources. Consequently, the requirement for tritium handling and usage will continue to increase in the future. An important future contributor is nuclear fusion power plants and facilities. Essential safety regulations and procedures require effective monitoring and measurements of tritium concentrations in workplaces. The unique characteristics of tritium impose an important role on the criteria for its detection and measurement. As tritium decays by the emission of soft beta particles, maximum 18 keV, it cannot be readily detected by commonly used detectors. Specially built monitors are required. Additional complications occur due to the presence of other radioactive isotopes or ambient radiation fields and because of the high diffusivity of tritium. When it is in oxidized form it is 25000 times more hazardous biologically than when in elemental form. Therefore, contamination of the monitor is expected and compound specific monitors are important. A summary is given of the various well known methods of detecting tritium-in-air. This covers the direct as well as the indirect measuring techniques, although each has been continually improved and further developed, nevertheless, each has its own limitations. Ionization chambers cannot discriminate against airborne P emitters. Proportional counters have a narrow operating range, 3-4 decades, and have poor performance in relatively high humid environments and require a dry counting gas. Liquid scintillation counters are sensitive, but inspection of the sample is slow and they produce chemical liquid waste. A new way to improve the sensitivity of detecting tritium with plastic scintillators has been developed. The technique is based on a non-line-of-sight implantation of tritium ions into a 20 mum plastic scintillator using a plasma source ion implantation (PSII) technique, This type of source is different, superior to the line-of-sight implantation and requires no additional beam handling. It is capable of implanting ion species in a broad beam configuration into the entire surface of a target. The technique requires a special ion source with special characteristics of the type obtained from a surfatron plasma source. This ion source has a large high ion density plasma with minimum contamination and produces ions of low temperature. It was constructed to ionize the sampled air and to produce a plasma over a wide range of pressure, 4-0.1 mTorr. A plasma source ion implantation cell was designed and constructed using mathematical modeling with personal computer, to optimize the essential variables of the design and to estimate the implantation rate under different operation conditions. Also, a high voltage pulse modulator was designed and constructed to produce a series of 10 musec pulses (up to 2 MHz) with a maximum magnitude of -60 kV. The developed device was capable of ionizing air samples and implanting the resulting ions into a plastic scintillator. Two different methods to enhance the collection and deposition of the tritium ions, have been proposed and assessed. A movable prototype device for monitoring environmental tritium in air has been designed and constructed. Although this prototype was not fully tested, the primary calculations have shown that measurable concentrations of tritium ions can be collected from an air sample, with tritium activity ranging from 0.3 Bq/cm3 down to 0.03 mBq/cm3, in a short time, to the order of seconds, on-line. This sensitivity fulfills the requirement for environmental monitoring.

Processing of silicon solar cells by ion implantation and laser annealing

NASA Technical Reports Server (NTRS)

Minnucci, J. A.; Matthei, K. W.; Greenwald, A. C.

1981-01-01

Methods to improve the radiation tolerance of silicon cells for spacecraft use are described. The major emphasis of the program was to reduce the process-induced carbon and oxygen impurities in the junction and base regions of the solar cell, and to measure the effect of reduced impurity levels on the radiation tolerance of cells. Substrates of 0.1, 1.0 and 10.0 ohm-cm float-zone material were used as starting material in the process sequence. High-dose, low-energy ion implantation was used to form the junction in n+p structures. Implant annealing was performed by conventional furnace techniques and by pulsed laser and pulsed electron beam annealing. Cells were tested for radiation tolerance at Spire and NASA-LeRC. After irradiation by 1 MeV electrons to a fluence of 10 to the 16th power per sq cm, the cells tested at Spire showed no significant process induced variations in radiation tolerance. However, for cells tested at Lewis to a fluence of 10 to the 15th power per sq cm, ion-implanted cells annealed in vacuum by pulsed electron beam consistently showed the best radiation tolerance for all cell resistivities.

Investigation of radiation hardened SOI wafer fabricated by ion-cut technique

NASA Astrophysics Data System (ADS)

Chang, Yongwei; Wei, Xing; Zhu, Lei; Su, Xin; Gao, Nan; Dong, Yemin

2018-07-01

Total ionizing dose (TID) effect on Silicon-on-Insulator (SOI) wafers due to inherent buried oxide (BOX) is a significant concern as it leads to the degradation of electrical properties of SOI-based devices and circuits, even failures of the systems associated with them. This paper reports the radiation hardening implementation of SOI wafer fabricated by ion-cut technique integrated with low-energy Si+ implantation. The electrical properties and radiation response of pseudo-MOS transistors are analyzed. The results demonstrate that the hardening process can significantly improve the TID tolerance of SOI wafers by generating Si nanocrystals (Si-NCs) within the BOX. The presence of Si-NCs created through Si+ implantation is evidenced by high-resolution transmission electron microscopy (HR-TEM). Under the pass gate (PG) irradiation bias, the anti-radiation properties of H-gate SOI nMOSFETs suggest that the radiation hardened SOI wafers with optimized Si implantation dose can perform effectively in a radiation environment. The radiation hardening process provides an excellent way to reinforce the TID tolerance of SOI wafers.

Bilateral implant reconstruction does not affect the quality of postmastectomy radiation therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, Alice Y., E-mail: hoa1234@mskcc.org; Patel, Nisha; Ohri, Nisha

To determine if the presence of bilateral implants, in addition to other anatomic and treatment-related variables, affects coverage of the target volume and dose to the heart and lung in patients receiving postmastectomy radiation therapy (PMRT). A total of 197 consecutive women with breast cancer underwent mastectomy and immediate tissue expander (TE) placement, with or without exchange for a permanent implant (PI) before radiation therapy at our center. PMRT was delivered with 2 tangential beams + supraclavicular lymph node field (50 Gy). Patients were grouped by implant number: 51% unilateral (100) and 49% bilateral (97). The planning target volume (PTV)more » (defined as implant + chest wall + nodes), heart, and ipsilateral lung were contoured and the following parameters were abstracted from dose-volume histogram (DVH) data: PTV D{sub 95%} > 98%, Lung V{sub 20}Gy > 30%, and Heart V{sub 25}Gy > 5%. Univariate (UVA) and multivariate analyses (MVA) were performed to determine the association of variables with these parameters. The 2 groups were well balanced for implant type and volume, internal mammary node (IMN) treatment, and laterality. In the entire cohort, 90% had PTV D{sub 95%} > 98%, indicating excellent coverage of the chest wall. Of the patients, 27% had high lung doses (V{sub 20}Gy > 30%) and 16% had high heart doses (V{sub 25}Gy > 5%). No significant factors were associated with suboptimal PTV coverage. On MVA, IMN treatment was found to be highly associated with high lung and heart doses (both p < 0.0001), but implant number was not (p = 0.54). In patients with bilateral implants, IMN treatment was the only predictor of dose to the contralateral implant (p = 0.001). In conclusion, bilateral implants do not compromise coverage of the target volume or increase lung and heart dose in patients receiving PMRT. The most important predictor of high lung and heart doses in patients with implant-based reconstruction, whether unilateral or bilateral, is treatment of the IMNs. Refinement of radiation techniques in reconstructed patients who require comprehensive nodal irradiation is warranted.« less

Clinical use of isotope cardiac pacemakers (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, J.; Kreutzberg, B.

1973-01-01

Plutoninm-235 having a half-life of 86.4 yrs has proved suitable as a long-life energy source for a cardiac pacemaker. The radiation dose of this pacemaker is below the I. C. R. P.-recommended values. As the isotope pacemaker costs three times as much as a conventional pacemaker, the merits of implanting an isotope pacemaker vs. the conventional kind are discussed. A survey is given of the cases in which an isotope pacemaker has been used. (GE)

Dosimetric evaluation of the effect of dental implants in head and neck radiotherapy.

PubMed

Ozen, Julide; Dirican, Bahar; Oysul, Kaan; Beyzadeoglu, Murat; Ucok, Ozlem; Beydemir, Bedri

2005-06-01

The aim of the study was to examine the dose enhancement from scattered radiation at bone-dental implant interfaces during simulated head and neck radiotherapy. Four cylindrical titanium dental implants with 3 different sizes and lengths were implanted into a human mandible in 4 different positions. Ionization measurements for 6 MV X, 25 MV X, and Co-60 gamma rays were done. Thermoluminescent dosimeter (TLD 100 ) chips were used to measure radiation dose enhancement due to the scattered electrons from titanium and electronic disequilibrium at the tissue-metal interface. The results showed that for Co-60, there is a 21% maximum increase in dose to alveolar mandibular bone at the close proximity to the titanium. For 6-MV x-rays the dose enhancement increase was almost the same or slightly lower than for Co-60, while for 25-MV high-energy x-rays, dose enhancement was lower than that of others. This increase in dose enhancement fell off rapidly and became insignificant at 2 mm from the interface. Total dose that may lead to osteoradionecrosis risk of the mandible is slightly but not significantly affected by the scattered dose of the dental implants of lower jaw in the radiation field exposed to 3 different radiation beams.

Radiation exposure to operator and patients during cardiac electrophysiology study, radiofrequency catheter ablation and cardiac device implantation procedures

NASA Astrophysics Data System (ADS)

Lee, C. H.; Cho, J. H.; Park, S. J.; Kim, J. S.; On, Y. K.; Huh, J.

2015-10-01

The purpose of this study was to measure the radiation exposure to operator and patient during cardiac electrophysiology study, radiofrequency catheter ablation and cardiac device implantation procedures and to calculate the allowable number of cases per year. We carried out 9 electrophysiology studies, 40 radiofrequency catheter ablation and 11 cardiac device implantation procedures. To measure occupational radiation dose and dose-area product (DAP), 13 photoluminescence glass dosimeters were placed at eyes (inside and outside lead glass), thyroids (inside and outside thyroid collar), chest (inside and outside lead apron), wrists, genital of the operator (inside lead apron), and 6 of photoluminescence glass dosimeters were placed at eyes, thyroids, chest and genital of the patient. Exposure time and DAP values were 11.7 ± 11.8 min and 23.2 ± 26.2 Gy cm2 for electrophysiology study; 36.5 ± 42.1 min and 822.4 ± 125.5 Gy cm2 for radiofrequency catheter ablation; 16.2 ± 9.3 min and 27.8 ± 16.5 Gy cm2 for cardiac device implantation procedure, prospectively. 4591 electrophysiology studies can be conducted within the occupational exposure limit for the eyes (150 mSv), and 658-electrophysiology studies with radiofrequency catheter ablation can be carried out within the occupational exposure limit for the hands (500 mSv). 1654 cardiac device implantation procedure can be conducted within the occupational exposure limit for the eyes (150 mSv). The amounts of the operator and patient's radiation exposure were comparatively small. So, electrophysiology study, radio frequency catheter ablation and cardiac device implantation procedures are safe when performed with modern equipment and optimized protective radiation protect equipment.

Complications After Mastectomy and Immediate Breast Reconstruction for Breast Cancer: A Claims-Based Analysis

PubMed Central

Jagsi, Reshma; Jiang, Jing; Momoh, Adeyiza O.; Alderman, Amy; Giordano, Sharon H.; Buchholz, Thomas A.; Pierce, Lori J.; Kronowitz, Steven J.; Smith, Benjamin D.

2016-01-01

Objective To evaluate complications after post-mastectomy breast reconstruction, particularly in the setting of adjuvant radiotherapy. Summary-Background Data Most studies of complications after breast reconstruction have been conducted at centers of excellence; relatively little is known about complication rates in radiated patients treated in the broader community. This information is relevant for breast cancer patients' decision-making. Methods Using the claims-based MarketScan database, we described complications in 14,894 women undergoing mastectomy for breast cancer from 1998-2007 who received immediate autologous reconstruction (n=2637), immediate implant-based reconstruction (n=3007), or no reconstruction within the first two postoperative years (n=9250). We used a generalized estimating equation to evaluate associations between complications and radiotherapy over time. Results Wound complications were diagnosed within the first two postoperative years in 2.3% of patients without reconstruction, 4.4% with implants, and 9.5% with autologous reconstruction (p<0.001). Infection was diagnosed within the first two postoperative years in 12.7% of patients without reconstruction, 20.5% with implants, and 20.7% with autologous reconstruction (p<0.001). 5219 (35%) women received radiation. Radiation was not associated with infection in any surgical group within the first six months but was associated with an increased risk of infection in months 7-24 in all three groups (each p<0.001). In months 7-24, radiation was associated with higher odds of implant removal in patients with implant reconstruction (OR 1.48, p<0.001) and fat necrosis in those with autologous reconstruction (OR=1.55; P=0.01). Conclusions Complication risks after immediate breast reconstruction differ by approach. Radiation therapy appears to modestly increase certain risks, including infection and implant removal. PMID:25876011

Effect of polychromatic visible light on proliferation of tumor cells under conditions in vitro and in vivo—after implantation to experimental animals

NASA Astrophysics Data System (ADS)

Knyazev, N. A.; Samoilova, K. A.; Filatova, N. A.; Galaktionova, A. A.

2009-06-01

The question of the character of effect of visible and near infrared (IR) radiation of Sun and artificial sources on growth of malignant tumors remains open due to controversy and a relatively small amount of available data, which restricts use of this most important environmental and the efficient physiotherapeutic factors at various human pathological states and first of all at the rehabilitation of oncological patients after radical methods of cancer treatment (surgical removal of tumor, intensive medication and radiation therapy), when immunomodulatory antiinflamatory, wound-healing and analgesic properties of visible and near IR light can be drawn. In the present work, using polychromatic visible light, close to this dominant component of the terrestrial solar radiation (380-750 nm, 40 mW/cm2) we irradiated tumor cells of the murine hepatoma (MH-22a line) under conditions in vitro (the monolayer of cells in Petri dishes) and in vivo (after subcutaneous implantation of these cells to mice of the C3HA line). A high resistance of the MH-22a cells to polychromatic visible radiation has been established under conditions in vitro: irradiation at dose 24 J/cm2 did not inhibit their proliferation whereas a dose of 9.6 J/cm2, stimulated statistically significantly proliferation of the cells (by 24-40%). However, stimulation of the tumor cell proliferation, did not develop under conditions in vivo, when mice were irradiated (9.6 J/cm2)—daily for 5 days before the implantation of tumor cells and for 5 days after implantation (in the latter case there was a probability of transcutaneous irradiation of tumor cells). By implanting to the animals of tumor cells at various concentrations (from 2ṡ105 to 25ṡ103 cells per mouse), we did not revealed at any of 10 terms of observations for 41-45 days both an increase of incidence of the tumor development and acceleration of tumor growth as well as a decrease of the animals survival as compared with group of non-irradiated animals. Moreover, there was recorded a decrease of incidence of the tumor development—by 16-24%, downregulation of the tumor growth rate—on average, by 40% and an increase of survival of the animals (by 20%). Thus, for the first time, an antitumor effect of polychromatic visible light has been shown at its application on the body surface of experimental animals.

Optical fibre luminescence sensor for real-time LDR brachytherapy dosimetry

NASA Astrophysics Data System (ADS)

Woulfe, P.; O'Keeffe, S.; Sullivan, F. J.

2018-02-01

An optical fibre sensor for monitoring low dose radiation is presented. The sensor is based on a scintillation material embedded within the optical fibre core, which emits visible light when exposed to low level ionising radiation. The incident level of ionising radiation can be determined by analysing the optical emission. An optical fibre sensor is developed, based on radioluminescence whereby radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 700μm of a 1mm plastic optical fibre. The sensor is designed for in-vivo monitoring of the radiation dose during radio-active seed implantation for low dose rate (LDR) brachytherapy, in prostate cancer treatment, providing radiation oncologists with real-time information of the radiation dose to the target area and/or nearby organs at risk (OARs). The radiation from the brachytherapy seeds causes emission of visible light from the scintillation material through the process of radioluminescence, which penetrates the fibre, propagating along the optical fibre for remote detection using a multi-pixel photon counter. The sensor demonstrates a high sensitivity to 0.397mCi of Iodine125, the radioactive source most commonly used in brachytherapy for treating prostate cancer.

ASPS clinical practice guideline summary on breast reconstruction with expanders and implants.

PubMed

Alderman, Amy; Gutowski, Karol; Ahuja, Amy; Gray, Diedra

2014-10-01

After reading this article, participants should be able to: 1. Understand the evidence regarding the timing of expander/implant breast reconstruction in the setting of radiation therapy. 2. Discuss the implications of a patient's risk factors for possible outcomes and complications of expander/implant breast reconstruction. 3. Implement proper prophylactic antibiotic protocols. 4. Use the guidelines to improve their own clinical outcomes and reduce complications. In March of 2013, the Executive Committee of the American Society of Plastic Surgeons approved an evidence-based guideline on breast reconstruction with expanders and implants, as developed by a guideline-specific work group commissioned by the society's Health Policy Committee. The guideline addresses ten clinical questions: patient education, immediate versus delayed reconstruction, risk factors, radiation therapy, chemotherapy, hormonal therapy, antibiotic prophylaxis, acellular dermal matrix, monitoring for cancer recurrence, and oncologic outcomes associated with implant-based reconstruction. The evidence indicates that patients undergoing mastectomy should be offered a preoperative referral to a plastic surgeon. Evidence varies regarding the association between postoperative complications and timing of postmastectomy expander/implant breast reconstruction. Evidence is limited regarding the optimal timing of expand/implant reconstruction in the setting of radiation therapy but suggests that irradiation to the expander or implant is associated with an increased risk of postoperative complications. Evidence also varies regarding the association between acellular dermal matrix and surgical complications in the setting of postmastectomy expander/implant reconstruction. Data support the use of an appropriate preoperative antibiotic, but antibiotics should be discontinued within 24 hours of the procedure, unless a surgical drain is present. Furthermore, postmastectomy expander/implant breast reconstruction does not adversely affect oncologic outcomes.

A tool to automatically analyze electromagnetic tracking data from high dose rate brachytherapy of breast cancer patients.

PubMed

Götz, Th I; Lahmer, G; Strnad, V; Bert, Ch; Hensel, B; Tomé, A M; Lang, E W

2017-01-01

During High Dose Rate Brachytherapy (HDR-BT) the spatial position of the radiation source inside catheters implanted into a female breast is determined via electromagnetic tracking (EMT). Dwell positions and dwell times of the radiation source are established, relative to the patient's anatomy, from an initial X-ray-CT-image. During the irradiation treatment, catheter displacements can occur due to patient movements. The current study develops an automatic analysis tool of EMT data sets recorded with a solenoid sensor to assure concordance of the source movement with the treatment plan. The tool combines machine learning techniques such as multi-dimensional scaling (MDS), ensemble empirical mode decomposition (EEMD), singular spectrum analysis (SSA) and particle filter (PF) to precisely detect and quantify any mismatch between the treatment plan and actual EMT measurements. We demonstrate that movement artifacts as well as technical signal distortions can be removed automatically and reliably, resulting in artifact-free reconstructed signals. This is a prerequisite for a highly accurate determination of any deviations of dwell positions from the treatment plan.

A tool to automatically analyze electromagnetic tracking data from high dose rate brachytherapy of breast cancer patients

PubMed Central

Lahmer, G.; Strnad, V.; Bert, Ch.; Hensel, B.; Tomé, A. M.; Lang, E. W.

2017-01-01

During High Dose Rate Brachytherapy (HDR-BT) the spatial position of the radiation source inside catheters implanted into a female breast is determined via electromagnetic tracking (EMT). Dwell positions and dwell times of the radiation source are established, relative to the patient’s anatomy, from an initial X-ray-CT-image. During the irradiation treatment, catheter displacements can occur due to patient movements. The current study develops an automatic analysis tool of EMT data sets recorded with a solenoid sensor to assure concordance of the source movement with the treatment plan. The tool combines machine learning techniques such as multi-dimensional scaling (MDS), ensemble empirical mode decomposition (EEMD), singular spectrum analysis (SSA) and particle filter (PF) to precisely detect and quantify any mismatch between the treatment plan and actual EMT measurements. We demonstrate that movement artifacts as well as technical signal distortions can be removed automatically and reliably, resulting in artifact-free reconstructed signals. This is a prerequisite for a highly accurate determination of any deviations of dwell positions from the treatment plan. PMID:28934238

Interference between active implanted medical devices and electromagnetic field emitting devices is rare but real: results of an incidence study in a population of physicians in France.

PubMed

Hours, Martine; Khati, Inès; Hamelin, Joel

2014-03-01

Assessing the behavior of active implanted medical devices (AIMDs) in response to electromagnetic field (EMF) transmitters is a current issue of great importance. Given the numerous telecommunication systems and our lack of knowledge as to the impact of electromagnetic effects, this study investigated the reality of possible AIMD disturbance by EMFs by interviewing health professionals. A self-administered postal questionnaire was sent to almost 5,000 physicians in five specialties: cardiology; endocrinology; ears, nose, and throat; urology; and neurology. It collected data on the existence and annual number of incidents observed and the conditions under which they occurred, the EMF sources involved, and the means of managing the malfunctions. A total of 1,188 physicians agreed to participate. Sixteen percent of participants reported cases of implant failure, three-quarters of whom, mainly in cardiology, reported rates of at least one incident per year-amounting to more than 100 incidents per year in all. Severity appeared to be moderate (discomfort or transient symptoms), but frequently required resetting or, more rarely, replacing the device. Some serious incidents were, however, reported. The sources implicated were basically of two types: electronic security systems (antitheft and airport gates) and medical electromagnetic radiation devices. These incidents were poorly reported within the public health system, preventing follow-up and effective performance of alert and surveillance functions. Although minor, the risk of interference between EMF sources and AIMDs is real and calls for vigilance. It particularly concerns antitheft and airport security gates, though other sources may also cause incidents. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

Nano-size defects in arsenic-implanted HgCdTe films: a HRTEM study

NASA Astrophysics Data System (ADS)

Bonchyk, O. Yu.; Savytskyy, H. V.; Swiatek, Z.; Morgiel, Y.; Izhnin, I. I.; Voitsekhovskii, A. V.; Korotaev, A. G.; Mynbaev, K. D.; Fitsych, O. I.; Varavin, V. S.; Dvoretsky, S. A.; Marin, D. V.; Yakushev, M. V.

2018-02-01

Radiation damage and its transformation under annealing were studied with bright-field and high-resolution transmission electron microscopy for arsenic-implanted HgCdTe films with graded-gap surface layers. In addition to typical highly defective layers in as-implanted material, a 50 nm-thick sub-surface layer with very low defect density was observed. The main defects in other layers after implantation were dislocation loops, yet after arsenic activation annealing, the dominating defects were single dislocations. Transport (from depth to surface), transformation and annihilation of radiation-induced defects were observed as a result of annealing, with the depth with the maximum defect density decreasing from 110 to 40 nm.

Reduction in Susceptibility of MOS Devices to Radiation- and Electrically-Induced Defects

DTIC Science & Technology

2012-05-01

current density of 150 nA/cm2 for a time varying between 5 and 60 sec. Following implantation , the PMMA was etched off, and circular Al dots (2.67 x 10...calculations showing location of He ions implanted at 5.2 keV through 70 nm of PMMA on 35.6 nm SiO2. We have done TRIM calculations for energies...Instability (NBTI) and to radiation damage could be reduced. To that end, two techniques were attempted. In the first attempt, helium ions were implanted

WE-FG-BRA-06: Systematic Study of Target Localization for Bioluminescence Tomography Guided Radiation Therapy for Preclinical Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, B; Reyes, J; Wong, J

Purpose: To overcome the limitation of CT/CBCT in guiding radiation for soft tissue targets, we developed a bioluminescence tomography(BLT) system for preclinical radiation research. We systematically assessed the system performance in target localization and the ability of resolving two sources in simulations, phantom and in vivo environments. Methods: Multispectral images acquired in single projection were used for the BLT reconstruction. Simulation studies were conducted for single spherical source radius from 0.5 to 3 mm at depth of 3 to 12 mm. The same configuration was also applied for the double sources simulation with source separations varying from 3 to 9more » mm. Experiments were performed in a standalone BLT/CBCT system. Two sources with 3 and 4.7 mm separations placed inside a tissue-mimicking phantom were chosen as the test cases. Live mice implanted with single source at 6 and 9 mm depth, 2 sources with 3 and 5 mm separation at depth of 5 mm or 3 sources in the abdomen were also used to illustrate the in vivo localization capability of the BLT system. Results: Simulation and phantom results illustrate that our BLT can provide 3D source localization with approximately 1 mm accuracy. The in vivo results are encouraging that 1 and 1.7 mm accuracy can be attained for the single source case at 6 and 9 mm depth, respectively. For the 2 sources study, both sources can be distinguished at 3 and 5 mm separations at approximately 1 mm accuracy using 3D BLT but not 2D bioluminescence image. Conclusion: Our BLT/CBCT system can be potentially applied to localize and resolve targets at a wide range of target sizes, depths and separations. The information provided in this study can be instructive to devise margins for BLT-guided irradiation and suggests that the BLT could guide radiation for multiple targets, such as metastasis. Drs. John W. Wong and Iulian I. Iordachita receive royalty payment from a licensing agreement between Xstrahl Ltd and Johns Hopkins University.« less

On the use of particle filters for electromagnetic tracking in high dose rate brachytherapy.

PubMed

Götz, Th I; Lahmer, G; Brandt, T; Kallis, K; Strnad, V; Bert, Ch; Hensel, B; Tomé, A M; Lang, E W

2017-09-12

Modern radiotherapy of female breast cancers often employs high dose rate brachytherapy, where a radioactive source is moved inside catheters, implanted in the female breast, according to a prescribed treatment plan. Source localization relative to the patient's anatomy is determined with solenoid sensors whose spatial positions are measured with an electromagnetic tracking system. Precise sensor dwell position determination is of utmost importance to assure irradiation of the cancerous tissue according to the treatment plan. We present a hybrid data analysis system which combines multi-dimensional scaling with particle filters to precisely determine sensor dwell positions in the catheters during subsequent radiation treatment sessions. Both techniques are complemented with empirical mode decomposition for the removal of superimposed breathing artifacts. We show that the hybrid model robustly and reliably determines the spatial positions of all catheters used during the treatment and precisely determines any deviations of actual sensor dwell positions from the treatment plan. The hybrid system only relies on sensor positions measured with an EMT system and relates them to the spatial positions of the implanted catheters as initially determined with a computed x-ray tomography.

Effect of different sterilization modes on the surface morphology, ion release, and bone reaction of retrieved micro-implants.

PubMed

El-Wassefy, Noha; El-Fallal, Abeer; Taha, Mahasen

2015-01-01

To compare as-received and sterilized micro-implants in order to assess the prospects of reusing them. Forty micro-implants from a single manufacturing lot were used in the study. Thirty were retrieved from patients after successful service in their mouth and with no signs of failure. The retrieved micro-implants were divided into three groups, according to method of sterilization: autoclave, gamma radiation, or ultraviolet radiation. All groups were subjected to scanning electron microscope analysis for surface morphology assessment. The specimens were immersed in a standard simulated body-fluid solution kept at 37°C in an incubator; the solution was then withdrawn at 24 hours and 30 days to evaluate aluminum and vanadium ion release by atomic absorption spectrophotometer in parts per billion. The micro-implants were then surgically implanted into the tibia of rabbits for a 1-month healing period, and the bone-implant blocks were processed for routine histologic examination. This study revealed that sterilized micro-implants had altered surface topography, different ion release values, and different histologic cell reactions than the as-received micro-implants. Within the limitations of this study, it can be concluded that retrieved self-drilling micro-implants have tip sharpness variations that require correction before insertion by bone drilling. The autoclave-sterilized micro-implants showed better histologic results than micro-implants sterilized by gamma or ultraviolet rays.

Optical fibre luminescence sensor for real-time LDR brachytherapy dosimetry

NASA Astrophysics Data System (ADS)

Woulfe, P.; Sullivan, F. J.; O'Keeffe, S.

2016-05-01

An optical fibre sensor for monitoring low dose radiation is presented. The sensor is based on a scintillation material embedded within the optical fibre core, which emits visible light when exposed to low level ionising radiation. The incident level of ionising radiation can be determined by analysing the optical emission. An optical fibre sensor is presented, based on radioluminescence whereby radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 250μm of a 500μm plastic optical fibre. The sensor is designed for in-vivo monitoring of the radiation dose during radio-active seed implantation for brachytherapy, in prostate cancer treatment, providing oncologists with real-time information of the radiation dose to the target area and/or nearby critical structures. The radiation from the brachytherapy seeds causes emission of visible light from the scintillation material through the process of radioluminescence, which penetrates the fibre, propagating along the optical fibre for remote detection using a multi-pixel photon counter. The sensor demonstrates a high sensitivity to Iodine-125, the radioactive source most commonly used in brachytherapy for treating prostate cancer.

Prostate brachytherapy

MedlinePlus

Implant therapy - prostate cancer; Radioactive seed placement; Internal radiation therapy - prostate; High dose radiation (HDR) ... CT scan to plan and then place the seeds that deliver radiation into your prostate. The seeds ...

Application of high resolution synchrotron micro-CT radiation in dental implant osseointegration.

PubMed

Neldam, Camilla Albeck; Lauridsen, Torsten; Rack, Alexander; Lefolii, Tore Tranberg; Jørgensen, Niklas Rye; Feidenhans'l, Robert; Pinholt, Else Marie

2015-06-01

The purpose of this study was to describe a refined method using high-resolution synchrotron radiation microtomography (SRmicro-CT) to evaluate osseointegration and peri-implant bone volume fraction after titanium dental implant insertion. SRmicro-CT is considered gold standard evaluating bone microarchitecture. Its high resolution, high contrast, and excellent high signal-to-noise-ratio all contribute to the highest spatial resolutions achievable today. Using SRmicro-CT at a voxel size of 5 μm in an experimental goat mandible model, the peri-implant bone volume fraction was found to quickly increase to 50% as the radial distance from the implant surface increased, and levelled out to approximately 80% at a distance of 400 μm. This method has been successful in depicting the bone and cavities in three dimensions thereby enabling us to give a more precise answer to the fraction of the bone-to-implant contact compared to previous methods. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

DTI and pathological changes in a rabbit model of radiation injury to the spinal cord after 125I radioactive seed implantation

PubMed Central

Cao, Xia; Fang, Le; Cui, Chuan-yu; Gao, Shi; Wang, Tian-wei

2018-01-01

Excessive radiation exposure may lead to edema of the spinal cord and deterioration of the nervous system. Magnetic resonance imaging can be used to judge and assess the extent of edema and to evaluate pathological changes and thus may be used for the evaluation of spinal cord injuries caused by radiation therapy. Radioactive 125I seeds to irradiate 90% of the spinal cord tissue at doses of 40–100 Gy (D90) were implanted in rabbits at T10 to induce radiation injury, and we evaluated their safety for use in the spinal cord. Diffusion tensor imaging showed that with increased D90, the apparent diffusion coefficient and fractional anisotropy values were increased. Moreover, pathological damage of neurons and microvessels in the gray matter and white matter was aggravated. At 2 months after implantation, obvious pathological injury was visible in the spinal cords of each group. Magnetic resonance diffusion tensor imaging revealed the radiation injury to the spinal cord, and we quantified the degree of spinal cord injury through apparent diffusion coefficient and fractional anisotropy. PMID:29623940

Step-by-step full mouth rehabilitation of a nasopharyngeal carcinoma patient with tooth and implant-supported prostheses: A clinical report

PubMed Central

Alikhasi, Marzieh; Kazemi, Mahmood; Nokar, Saeed; Khojasteh, Arash; Sheikhzadeh, Sedigheh

2011-01-01

This clinical report presents a 46-year-old man diagnosed with nasopharyngeal carcinoma with the chief complaint of masticatory and speech deficiency because of radiation therapy. After a period of controlling post radiation caries, the patient was rehabilitated with tooth and implant supported metal ceramic restorations following surgical and endodontic intervention. PMID:22090777

Design of radiation resistant metallic multilayers for advanced nuclear systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhernenkov, Mikhail, E-mail: zherne@bnl.gov, E-mail: gills@bnl.gov; Gill, Simerjeet, E-mail: zherne@bnl.gov, E-mail: gills@bnl.gov; Stanic, Vesna

2014-06-16

Helium implantation from transmutation reactions is a major cause of embrittlement and dimensional instability of structural components in nuclear energy systems. Development of novel materials with improved radiation resistance, which is of the utmost importance for progress in nuclear energy, requires guidelines to arrive at favorable parameters more efficiently. Here, we present a methodology that can be used for the design of radiation tolerant materials. We used synchrotron X-ray reflectivity to nondestructively study radiation effects at buried interfaces and measure swelling induced by He implantation in Cu/Nb multilayers. The results, supported by transmission electron microscopy, show a direct correlation betweenmore » reduced swelling in nanoscale multilayers and increased interface area per unit volume, consistent with helium storage in Cu/Nb interfaces in forms that minimize dimensional changes. In addition, for Cu/Nb layers, a linear relationship is demonstrated between the measured depth-dependent swelling and implanted He density from simulations, making the reflectivity technique a powerful tool for heuristic material design.« less

Metal artifact suppression in megavoltage computed tomography

NASA Astrophysics Data System (ADS)

Schreiner, L. John; Rogers, Myron; Salomons, Greg; Kerr, Andrew

2005-04-01

There has been considerable interest in megavoltage CT (MVCT) imaging associated with the development of image guided radiation therapy. It is clear that MVCT can provide good image quality for patient setup verification with soft tissue contrast much better than noted in conventional megavoltage portal imaging. In addition, it has been observed that MVCT images exhibit considerably reduced artifacts surrounding metal implants (e.g., surgical clips, hip implants, dental fillings) compared to conventional diagnostic CT images (kVCT). When encountered, these artifacts greatly limit the usefulness of kVCT images, and a variety of solutions have been proposed to remove the artifacts, but these have met with only partial success. In this paper, we investigate the potential for CT imaging in regions surrounding metal implants using high-energy photons from a Cobalt-60 source and from a 4 MV linear accelerator. MVCT and kVCT images of contrast phantoms and a phantom containing a hip prosthesis are compared and analysed. We show that MVCT scans provide good fidelity for CT number quantification in the high-density regions of the images, and in the regions immediately adjacent to the metal implants. They also provide structural details within the high-density inserts and implants. Calculations will show that practical clinical MVCT imaging, able to detect 3% contrast objects, should be achievable with doses of about 2.5cGy. This suggests that MVCT not only has a role in radiotherapy treatment planning and guidance, but may also be indicated for surgical guidance and follow-up in regions where metal implants cannot be avoided.

Dosimetric comparison between model 9011 and 6711 sources in prostate implants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hualin, E-mail: zhang248@iupui.edu; Arizona Oncology Services, Phoenix, AZ; Beyer, David

2013-07-01

The purpose of this work is to evaluate the model 9011 iodine-125 ({sup 125}I) in prostate implants by comparing dosimetric coverage provided by the 6711 vs 9011 source implants. Postimplant dosimetry was performed in 18 consecutively implanted patients with prostate cancer. Two were implanted with the 9011 source and 16 with the 6711 source. For purposes of comparison, each implant was then recalculated assuming use of the other source. The same commercially available planning system was used and the specific source data for both 6711 and 9011 products were entered. The results of these calculations are compared side by sidemore » in the terms of the isodose values covering 100% (D100) and 90% (D90) of prostate volume, and the percentages of volumes of prostate, bladder, rectum, and urethra covered by 200% (V200), 150% (V150), 100% (V100), 50% (V50), and 20% (V20) of the prescribed dose as well. The 6711 source data overestimate coverage by 6.4% (ranging from 4.9% to 6.9%; median 6.6%) at D100 and by 6.6% (ranging from 6.2% to 6.8%; median 6.6%) at D90 compared with actual 9011 data. Greater discrepancies of up to 67% are seen at higher dose levels: average reduction for V100 is 2.7% (ranging from 0.6% to 7.7%; median 2.3%), for V150 is 14.6% (ranging from 6.1% to 20.5%; median 15.3%), for V200 is 14.9% (ranging from 4.8% to 19.1%; median 16%); similarly seen in bladder, rectal, and urethral coverage. This work demonstrates a clear difference in dosimetric behavior between the 9011 and 6711 sources. Using the 6711 source data for 9011 source implants would create a pronounced error in dose calculation. This study provides evidence that the 9011 source can provide the same dosimetric quality as the 6711 source, if properly used; however, the 6711 source data should not be considered as a surrogate for the 9011 source implants.« less

Prospective study of direct radiation exposure measurements for family members living with patients with prostate (125)I seed implantation: Evidence of radiation safety.

PubMed

Hanada, Takashi; Yorozu, Atsunori; Shinya, Yukiko; Kuroiwa, Nobuko; Ohashi, Toshio; Saito, Shiro; Shigematsu, Naoyuki

2016-01-01

To broaden the current understanding of radiation exposure and risk and to provide concrete evidence of radiation safety related to (125)I seed implantation. Direct radiation exposure measurements were obtained from dosimeters provided to 25 patients who underwent (125)I seed implantation, along with their family members. The estimated lifetime exposure dose and the precaution time for holding children near the patient's chest were calculated in two study periods. During the first and second study period, the mean estimated lifetime exposure doses were, respectively, 7.61 (range: 0.45, 20.21) mSv and 6.84 (range: 0.41, 19.20) mSv for patients, and 0.19 (range: 0.02, 0.54) mSv and 0.25 (range: 0.04, 1.00) mSv for family members. The mean ratios of first and second period measurements were 1.05 (range: 0.44, 3.18) for patients and 1.82 (range: 0.21, 7.04) for family members. The corresponding absolute differences between first and second period measurements were -0.77 (range: -11.40, 7.63) mSv and 0.06 (range: -0.26, 0.79) mSv, respectively. Assuming a dose limit of 1 mSv, the precaution times for holding a child every day of the first and second periods were 250.9 (range: 71.3, 849.4) min and 275.2 (range: 75.0, 883.4) min, respectively. Assuming a dose limit of 0.5 mSv, the corresponding precaution times were 179.0 (range: 35.6, 811.5) min and 178.9 (range: 37.5, 1131.8) min, respectively. Our study demonstrated low radiation exposures to family members of patients undergoing (125)I prostate implantation. It was clear that (125)I seed implantation did not pose a threat to the safety of family members. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Defect evolution in ZnO and its effect on radiation tolerance.

PubMed

Lv, Jinpeng; Li, Xingji

2018-05-03

The origin of ZnO radiation resistance is fascinating but still unclear. Herein, we found that radiation tolerance of ZnO can be tuned by engineering intrinsic defects into the ZnO. The role played by native defects in the radiation tolerance of ZnO was systematically explored by carrying out N+ implantation on a set of home-grown ZnO nanocrystals with various lattice defect types and concentrations. Interestingly, decreasing the VO and Zni concentration significantly aggravated N+ radiation damage, indicating the presence of O-deficient defects to be the potential cause of the radiation hardness of ZnO. A similar phenomenon was also observed for H+-implanted ZnO. This work offers a new way to manipulate ZnO and endow it with desired physicochemical properties, and is expected to pave the way for its application in radiative environments.

Neuro-oncology update: radiation safety and nursing care during interstitial brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Randall, T.M.; Drake, D.K.; Sewchand, W.

Radiation control and safety are major considerations for nursing personnel during the care of patients receiving brachytherapy. Since the theory and practice of radiation applications are not part of the routine curriculum of nursing programs, the education of nurses and other health care professionals in radiation safety procedures is important. Regulatory agencies recommend that an annual safety course be given to all persons frequenting, using, or associated with patients containing radioactive materials. This article presents pertinent aspects of the principles and procedures of radiation safety, the role of personnel dose-monitoring devices, and the value of additional radiation control features, suchmore » as a lead cubicle, during interstitial brain implants. One institution's protocol and procedures for the care of high-intensity iridium-192 brain implants are discussed. Preoperative teaching guidelines and nursing interventions included in the protocol focus on radiation control principles.« less

An in vitro verification of strength estimation for moving an 125I source during implantation in brachytherapy.

PubMed

Tanaka, Kenichi; Kajimoto, Tsuyoshi; Hayashi, Takahiro; Asanuma, Osamu; Hori, Masakazu; Kamo, Ken-Ichi; Sumida, Iori; Takahashi, Yutaka; Tateoka, Kunihiko; Bengua, Gerard; Sakata, Koh-Ichi; Endo, Satoru

2018-04-11

This study aims to demonstrate the feasibility of a method for estimating the strength of a moving brachytherapy source during implantation in a patient. Experiments were performed under the same conditions as in the actual treatment, except for one point that the source was not implanted into a patient. The brachytherapy source selected for this study was 125I with an air kerma strength of 0.332 U (μGym2h-1), and the detector used was a plastic scintillator with dimensions of 10 cm × 5 cm × 5 cm. A calibration factor to convert the counting rate of the detector to the source strength was measured and then the accuracy of the proposed method was investigated for a manually driven source. The accuracy was found to be under 10% when the shielding effect of additional needles for implantation at other positions was corrected, and about 30% when the shielding was not corrected. Even without shielding correction, the proposed method can detect dead/dropped source, implantation of a source with the wrong strength, and a mistake in the number of the sources implanted. Furthermore, when the correction was applied, the achieved accuracy came close to within 7% required to find the Oncoseed 6711 (125I seed with unintended strength among the commercially supplied values of 0.392, 0.462 and 0.533 U).

Beam Profile Disturbances from Implantable Pacemakers or Implantable Cardioverter-Defibrillator Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gossman, Michael S., E-mail: mgossman@tsrcc.com; Comprehensive Heart and Vascular Associates, Heart and Vascular Center, Ashland, KY; Medtronic, Inc., External Research Program, Mounds View, MN

2011-01-01

The medical community is advocating for progressive improvement in the design of implantable cardioverter-defibrillators and implantable pacemakers to accommodate elevations in dose limitation criteria. With advancement already made for magnetic resonance imaging compatibility in some, a greater need is present to inform the radiation oncologist and medical physicist regarding treatment planning beam profile changes when such devices are in the field of a therapeutic radiation beam. Treatment plan modeling was conducted to simulate effects induced by Medtronic, Inc.-manufactured devices on therapeutic radiation beams. As a continuation of grant-supported research, we show that radial and transverse open beam profiles of amore » medical accelerator were altered when compared with profiles resulting when implantable pacemakers and cardioverter-defibrillators are placed directly in the beam. Results are markedly different between the 2 devices in the axial plane and the sagittal planes. Vast differences are also presented for the therapeutic beams at 6-MV and 18-MV x-ray energies. Maximum changes in percentage depth dose are observed for the implantable cardioverter-defibrillator as 9.3% at 6 MV and 10.1% at 18 MV, with worst distance to agreement of isodose lines at 2.3 cm and 1.3 cm, respectively. For the implantable pacemaker, the maximum changes in percentage depth dose were observed as 10.7% at 6 MV and 6.9% at 18 MV, with worst distance to agreement of isodose lines at 2.5 cm and 1.9 cm, respectively. No differences were discernible for the defibrillation leads and the pacing lead.« less

SU-F-19A-11: Retrospective Evaluation of Thermal Coverage by Thermobrachytherapy Seed Arrangements of Clinical LDR Prostate Implants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warrell, G; Shvydka, D; Chen, C

Purpose: The superiority of a properly-administered combination of radiation therapy and hyperthermia over radiation alone in treatment of human cancers has been demonstrated in multiple studies examining radiobiology, local control, and survival. Unfortunately, hyperthermia is not yet a common modality in oncology practice, due in part to the technical difficulty of heating a deep-seated target volume to sufficient temperature. To address this problem, our group has invented a thermobrachytherapy (TB) seed based on a commonly-used low dose-rate permanent brachytherapy seed for implant in solid tumors. Instead of the tungsten radiographic marker of the standard seed, the TB seed contains onemore » of a self-regulating ferromagnetic alloy. Placement of a patient implanted with such seeds in an oscillating magnetic field generates heat via induction of eddy currents. We present the results of studies of the capability of clinically-realistic TB seed arrangements to adequately heat defined target volumes. Methods: Seed distributions for several past LDR prostate permanent implant brachytherapy patients were reproduced in the finite element analysis software package COMSOL Multiphysics 4.4, with the difference that TB seeds were modelled, rather than the radiation-only seeds actually used for their treatments. The implant geometries were mainly of the modified peripheral loading type; a range of prostatic volumes and blood perfusion rates likely to be seen in a clinical setting were examined. Results: According to the simulations, when distributed to optimize radiation dose, TB seeds also produce sufficient heat to provide thermal coverage of the target given proper selection of the magnetic field strength. However, the thermal distributions may be improved by additional use of hyperthermia-only seeds. Conclusion: A dual-modality seed intended as an alternative to and using the same implantation apparatus and technique as the standard LDR permanent implant seed has been successfully evaluated for its ability to provide sufficient hyperthermia in clinically-realistic implants. This work was partially supported by the National Institutes of Health (NIH) STTR Grant No. R41 CA153631-01A1.« less

Near Field Radiation Characteristics of Implantable Square Spiral Chip Inductor Antennas for Bio-Sensors

NASA Technical Reports Server (NTRS)

Nessel, James A.; Simons, Rainee N.; Miranda, Felix A.

2007-01-01

The near field radiation characteristics of implantable Square Spiral Chip Inductor Antennas (SSCIA) for Bio-Sensors have been measured. Our results indicate that the measured near field relative signal strength of these antennas agrees with simulated results and confirm that in the near field region the radiation field is fairly uniform in all directions. The effects of parameters such as ground-plane, number of turns and microstrip-gap width on the performance of the SSCIA are presented. Furthermore, the SSCIA antenna with serrated ground plane produce a broad radiation pattern, with a relative signal strength detectable at distances within the range of operation of hand-held devices for self-diagnosis.

Ionizing radiation abrogates the pro-tumorigenic capacity of cancer-associated fibroblasts co-implanted in xenografts.

PubMed

Grinde, Maria Tunset; Vik, Jørg; Camilio, Ketil André; Martinez-Zubiaurre, Inigo; Hellevik, Turid

2017-04-25

Cancer-associated fibroblasts (CAFs) are abundantly present in solid tumors and affect tumorigenesis and therapeutic responses. In the context of clinical radiotherapy, the impact of irradiated CAFs to treatment outcomes is largely unexplored. Aiming at improving radiotherapy efficacy, we have here explored the effect of radiation on the inherent pro-tumorigenic capacity of CAFs in animals. Ionizing radiation was delivered to cultured CAFs as single-high or fractionated doses. Tumor development was compared in mice receiving A549 lung tumor cells admixed with irradiated or control CAFs. Biological mechanisms behind tumor growth regulation were investigated by quantitative histology and immunohistochemistry. Viability assessments confirmed that irradiated CAFs are fully functional prior to implantation. However, the enhanced tumorigenic effect observed in tumors co-implanted with control CAFs was abrogated in tumors established with irradiated CAFs. Experiments to ascertain fate of implanted fibroblasts showed that exogenously administered CAFs reside at the implantation site for few days, suggesting that tumor growth regulation from admixed CAFs take place during initial tumor formation. Our work demonstrate that irradiated CAFs lose their pro-tumorigenic potential in vivo, affecting angiogenesis and tumor engraftment. This finding propose a previously unknown advantageous effect induced by radiotherapy, adding to the direct cytotoxic effects on transformed epithelial cells.

Annealing kinetics of radiation defects in boron-implanted p-Hg1‑xCdxTe

NASA Astrophysics Data System (ADS)

Talipov, Niyaz; Voitsekhovskii, Alexander

2018-06-01

The results of studying the annealing kinetics of the radiation-induced donor-type defects in boron implanted p-type Hg1‑x Cd x Te (MCT) are presented. The annealing kinetics of the radiation donor centers depend significantly on the dose of B+ ions, that is on the initial level of structural defects generated in the MCT lattice by ion bombardment. The activation energy E A of annealing of donor defects generated by implantation of B+ ions increases with increasing dose and temperature of the post-implantation heat treatment under the SiO2 cap. The smaller the dose and the higher the initial hole concentration in p-MCT, the lower the temperature of a complete annealing of donor centers, which lies in the range 220–275 °C. In the initial stages of the post-implantation heat treatment, primary donor defects are annealed, and then, more stable secondary impurity-defect complexes are annealed. It was established for the first time that the activation energy of the donor defects annealing in bulk crystals and heteroepitaxial structures of MCT has two clearly pronounced regions: at low temperatures 90–130 °C, E A = 0.06 eV and at Т = 150–250 °C, E A = 0.71–0.86 eV.

The Relative Effects of Manual Versus Automatic Exposure Control on Radiation Dose to Vital Organs in Total Hip Arthroplasty.

PubMed

Harper, Katharine D; Li, Shidong; Jennings, Rachel; Amer, Kamil M; Haydel, Christopher; Ali, Sayed

2018-01-01

Technologic advances have reduced medical radiation exposure while maintaining image quality. The purpose of this study was to determine the effects of the presence of total hip arthroplasty implants, compared with native hips, on radiation exposure of the most radiosensitive organs when manual and automatic exposure control settings are used. Detection probes were placed at six locations (stomach, sigmoid colon, right pelvic wall, left pelvic wall, pubic symphysis, and anterior pubic skin) in a cadaver. Radiographs were obtained with the use of manual and automatic exposure control protocols, with exposures recorded. A total hip arthroplasty implant was placed in the cadaver, probe positioning was confirmed, and the radiographs were repeated, with exposure values recorded. The control probe placed at the stomach had values ranging from 0.00 mSv to 0.01 mSv in protocols with and without implants. With the manual protocol, exposures in the pelvis ranged from 0.36 mSv to 2.74 mSv in the native hip and from 0.33 mSv to 2.24 mSv after implant placement. The increases in exposure after implant placement, represented as relative risk, were as follows: stomach, 1.000; pubic symphysis, 0.818; left pelvic wall, 1.381; sigmoid colon, 1.550; right pelvic wall, 0.917; and anterior pubic skin, 1.015. With automatic exposure control, exposures in the pelvis ranged from 0.07 mSv to 0.89 mSv in the native hip and from 0.21 mSv to 1.15 mSv after implant placement. With automatic exposure control, the increases in exposure after implant placement, represented as relative risk, were as follows: stomach, 1.000; pubic symphysis, 1.292; left pelvic wall, 1.476; sigmoid colon, 2.182; right pelvic wall, 3.000; and anterior pubic skin, 1.378. The amount of radiation to which patients are exposed as a result of medical procedures or imaging, and whether exposure is associated with an increased risk of malignant transformation, are the subject of ongoing debate. We found that after insertion of a total hip arthroplasty implant, exposure values increased threefold at some anatomic locations and surpassed 1 mSv, the generally accepted threshold for concern. Radiation exposure to radiosensitive organs increased up to threefold after total hip implantation with automatic exposure control and up to approximately 1.5 times with the manual protocol. Doses were greater with manual exposures than with automatic exposure control (except at the control probe on the stomach, where exposure was negligible, as expected). However, after implant placement, doses increased more with automatic exposure control than with manual exposure. This difference can be attributed to increased scatter and the difficulty of dose modification because of the density of the implant. Current radiographic protocols should be reassessed to determine if the benefits of frequent radiographs outweigh the newly demonstrated risks.

Directional interstitial brachytherapy from simulation to application

NASA Astrophysics Data System (ADS)

Lin, Liyong

Organs at risk (OAR) are sometimes adjacent to or embedded in or overlap with the clinical target volume (CTV) to be treated. The purpose of this PhD study is to develop directionally low energy gamma-emitting interstitial brachytherapy sources. These sources can be applied between OAR to selectively reduce hot spots in the OARs and normal tissues. The reduction of dose over undesired regions can expand patient eligibility or reduce toxicities for the treatment by conventional interstitial brachytherapy. This study covers the development of a directional source from design optimization to construction of the first prototype source. The Monte Carlo code MCNP was used to simulate the radiation transport for the designs of directional sources. We have made a special construction kit to assemble radioactive and gold-shield components precisely into D-shaped titanium containers of the first directional source. Directional sources have a similar dose distribution as conventional sources on the treated side but greatly reduced dose on the shielded side, with a sharp dose gradient between them. A three-dimensional dose deposition kernel for the 125I directional source has been calculated. Treatment plans can use both directional and conventional 125I sources at the same source strength for low-dose-rate (LDR) implants to optimize the dose distributions. For prostate tumors, directional 125I LDR brachytherapy can potentially reduce genitourinary and gastrointestinal toxicities and improve potency preservation for low risk patients. The combination of better dose distribution of directional implants and better therapeutic ratio between tumor response and late reactions enables a novel temporary LDR treatment, as opposed to permanent or high-dose-rate (HDR) brachytherapy for the intermediate risk T2b and high risk T2c tumors. Supplemental external-beam treatments can be shortened with a better brachytherapy boost for T3 tumors. In conclusion, we have successfully finished the design optimization and construction of the first prototype directional source. Potential clinical applications and potential benefits of directional sources have been shown for prostate and breast tumors.

On the use of particle filters for electromagnetic tracking in high dose rate brachytherapy

NASA Astrophysics Data System (ADS)

Götz, Th I.; Lahmer, G.; Brandt, T.; Kallis, K.; Strnad, V.; Bert, Ch; Hensel, B.; Tomé, A. M.; Lang, E. W.

2017-10-01

Modern radiotherapy of female breast cancers often employs high dose rate brachytherapy, where a radioactive source is moved inside catheters, implanted in the female breast, according to a prescribed treatment plan. Source localization relative to the patient’s anatomy is determined with solenoid sensors whose spatial positions are measured with an electromagnetic tracking system. Precise sensor dwell position determination is of utmost importance to assure irradiation of the cancerous tissue according to the treatment plan. We present a hybrid data analysis system which combines multi-dimensional scaling with particle filters to precisely determine sensor dwell positions in the catheters during subsequent radiation treatment sessions. Both techniques are complemented with empirical mode decomposition for the removal of superimposed breathing artifacts. We show that the hybrid model robustly and reliably determines the spatial positions of all catheters used during the treatment and precisely determines any deviations of actual sensor dwell positions from the treatment plan. The hybrid system only relies on sensor positions measured with an EMT system and relates them to the spatial positions of the implanted catheters as initially determined with a computed x-ray tomography.

Ion implantation of solar cell junctions without mass analysis

NASA Technical Reports Server (NTRS)

Fitzgerald, D.; Tonn, D. G.

1981-01-01

This paper is a summary of an investigation to determine the feasibility of producing solar cells by means of ion implantation without the use of mass analysis. Ion implants were performed using molecular and atomic phosphorus produced by the vaporization of solid red phosphorus and ionized in an electron bombardment source. Solar cell junctions were ion implanted by mass analysis of individual molecular species and by direct unanalyzed implants from the ion source. The implant dose ranged from 10 to the 14th to 10 to the 16th atoms/sq cm and the energy per implanted atom ranged from 5 KeV to 40 KeV in this study.

Novel active stabilization technology in highly crosslinked UHMWPEs for superior stability

NASA Astrophysics Data System (ADS)

Oral, Ebru; Neils, Andrew L.; Wannomae, Keith K.; Muratoglu, Orhun K.

2014-12-01

Radiation cross-linked ultrahigh molecular weight polyethylene (UHMWPE) is the bearing of choice in joint arthroplasty. The demands on the longevity of this polymer are likely to increase with the recently advancing deterioration of the performance of alternative metal-on-metal implants. Vitamin E-stabilized, cross-linked UHMWPEs are considered the next generation of improved UHMWPE bearing surfaces for improving the oxidation resistance of the polymer. It was recently discovered that in the absence of radiation-induced free radicals, lipids absorbed into UHMWPE from the synovial fluid can initiate oxidation and result in new free radical-mediated oxidation mechanisms. In the presence of radiation-induced free radicals, it is possible for the polymer to oxidize through both existing free radicals at the time of implantation and through newly formed free radicals in vivo. Thus, we showed that reducing the radiation-induced free radicals in vitamin E-stabilized UHMWPE would increase its oxidative stability and presumably lead to improved longevity. We describe mechanical annealing and warm irradiation of irradiated vitamin E blends as novel methods to eliminate 99% of radiation-induced free radicals without sacrificing crystallinity. These are significant improvements in the processing of highly cross-linked UHMWPE for joint implants with improved longevity.

Pulsed source ion implantation apparatus and method

DOEpatents

Leung, Ka-Ngo

1996-01-01

A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted.

Superimposed coherent terahertz wave radiation from mono-energetically bunched multi-beam

DOE PAGES

Shin, Young -Min; Fermi National Accelerator Lab.

2012-06-27

Intense coherent radiation is obtained from multiple electron beams monochromatically bunched over the wide higher-order-mode (HOM) spectral band in the THz regime. The overmoded waveguide corrugated by dielectric-implanted staggered gratings superimposes evanescent waves emitted from the low energy electron beams. The dispersion and transmission simulations of the three-beam slow wave structure show that the first two fundamental modes (more » $$TE_{10}$$ and $$TE_{20}$$) are considerably suppressed ($$\\sim-50$$ dB) below the multi-beam resonating mode ($$TE_{30}$$) at the THz regime (0.8–1.24 THz). The theoretical calculations and particle-in-cell simulations show that with significantly higher interaction impedance and power growth rate radiation of the $$TE_{30}$$ mode is $$\\sim$$23 dBm and $$\\sim$$50 dBm stronger than the $$TE_{10}$$ and $$TE_{20}$$ modes around 1 THz, respectively. As a result, this highly selective HOM multi-beam interaction has potential applications for power THz sources and high intensity accelerators.« less

An overview of interstitial brachytherapy and hyperthermia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brandt, B.B.; Harney, J.

Interstitial thermoradiotherapy, an experimental cancer treatment that combines interstitial radiation implants (brachytherapy) and interstitial hyperthermia, is in the early stages of investigation. In accordance with the procedure used in a current national trial protocol, a 60-minute hyperthermia treatment is administered after catheters are placed into the tumor area while the patient is under general anesthesia. This is immediately followed by loading of radioactive Iridium-192 seeds into the catheters for a defined period of time. Once the prescribed radiation dose is delivered, the radioactive sources are removed and a second, 60-minute hyperthermia treatment is administered. Clinical trials with hyperthermia in combinationmore » with radiation have increased in recent years. Nurses caring for these patients need to become more knowledgeable about this investigational therapy. This paper provides an overview of the biologic rationale for this therapy, as well as a description of the delivery method and clinical application. Specific related nursing interventions are defined in a nursing protocol.23 references.« less

Electromagnetic interference in cardiac rhythm management devices.

PubMed

Sweesy, Mark W; Holland, James L; Smith, Kerry W

2004-01-01

Clinicians caring for cardiac device patients with implanted pacemakers or cardioverter defibrillators (ICDs) are frequently asked questions by their patients concerning electromagnetic interference (EMI) sources and the devices. EMI may be radiated or conducted and may be present in many different forms including (but not limited to) radiofrequency waves, microwaves, ionizing radiation, acoustic radiation, static and pulsed magnetic fields, and electric currents. Manufacturers have done an exemplary job of interference protection with device features such as titanium casing, signal filtering, interference rejection circuits, feedthrough capacitors, noise reversion function, and programmable parameters. Nevertheless, EMI remains a real concern and a potential danger. Many factors influence EMI including those which the patient can regulate (eg, distance from and duration of exposure) and some the patient cannot control (eg, intensity of the EMI field, signal frequency). Potential device responses are many and range from simple temporary oversensing to permanent device damage Several of the more common EMI-generating devices and their likely effects on cardiac devices are considered in the medical, home, and daily living and work environments.

Applications of Nuclear and Particle Physics Technology: Particles & Detection — A Brief Overview

NASA Astrophysics Data System (ADS)

Weisenberger, Andrew G.

A brief overview of the technology applications with significant societal benefit that have their origins in nuclear and particle physics research is presented. It is shown through representative examples that applications of nuclear physics can be classified into two basic areas: 1) applying the results of experimental nuclear physics and 2) applying the tools of experimental nuclear physics. Examples of the application of the tools of experimental nuclear and particle physics research are provided in the fields of accelerator and detector based technologies namely synchrotron light sources, nuclear medicine, ion implantation and radiation therapy.

Industrial Applications of Pulsed Power Technology

NASA Astrophysics Data System (ADS)

Takaki, Koichi; Katsuki, Sunao

Recent progress of the industrial applications of pulsed power is reviewed in this paper. Repetitively operated pulsed power generators with a moderate peak power have been developed for industrial applications. These generators are reliable and low maintenance. Development of the pulsed power generators helps promote industrial applications of pulsed power for such things as food processing, medical treatment, water treatment, exhaust gas treatment, ozone generation, engine ignition, ion implantation and others. Here, industrial applications of pulsed power are classified by application for biological effects, for pulsed streamer discharges in gases, for pulsed discharges in liquid or liquid-mixture, and for bright radiation sources.

Possible sources of neuroprotection following subretinal silicon chip implantation in RCS rats

NASA Astrophysics Data System (ADS)

Pardue, Machelle T.; Phillips, Michael J.; Yin, Hang; Fernandes, Alcides; Cheng, Yian; Chow, Alan Y.; Ball, Sherry L.

2005-03-01

Current retinal prosthetics are designed to stimulate existing neural circuits in diseased retinas to create a visual signal. However, implantation of retinal prosthetics may create a neurotrophic environment that also leads to improvements in visual function. Possible sources of increased neuroprotective effects on the retina may arise from electrical activity generated by the prosthetic, mechanical injury due to surgical implantation, and/or presence of a chronic foreign body. This study evaluates these three neuroprotective sources by implanting Royal College of Surgeons (RCS) rats, a model of retinitis pigmentosa, with a subretinal implant at an early stage of photoreceptor degeneration. Treatment groups included rats implanted with active and inactive devices, as well as sham-operated. These groups were compared to unoperated controls. Evaluation of retinal function throughout an 18 week post-implantation period demonstrated transient functional improvements in eyes implanted with an inactive device at 6, 12 and 14 weeks post-implantation. However, the number of photoreceptors located directly over or around the implant or sham incision was significantly increased in eyes implanted with an active or inactive device or sham-operated. These results indicate that in the RCS rat localized neuroprotection of photoreceptors from mechanical injury or a chronic foreign body may provide similar results to subretinal electrical stimulation at the current output evaluated here.

Transcorporal artificial urinary sphincter in radiated and non - radiated compromised urethra. Assessment with a minimum 2 year follow-up.

PubMed

Le Long, Erwann; Rebibo, John David; Nouhaud, Francois Xavier; Grise, Philippe

2016-01-01

to assess the efficacy of transcorporal artificial urinary sphincter (AUS) implantation on continence for male stress urinary incontinence in cases of prior surgical treatment or/and radiation failure, and as a first option in radiation patients. From March 2007 to August 2012, 37 male patients were treated with transcorporal AUS AMS™ 800. Twelve patients had primary placement of transcorporal cuff, a surgical option due to a previous history of radiation and 25 patients had secondary procedure after failure of AUS or urinary incontinence surgery. Functional urinary outcomes were assessed by daily pad use, 24-hour Pad-test and ICIQ-SF questionnaire. Quality of life and satisfaction were assessed based on I-QoL and PGI-I questionnaires. After a median of 32 months, the continence rate (0 to 1 pad) was 69.7%. Median pad test was 17.5g (0-159), mean ICIQ-SF score was 7.3/21 (±5.4) and mean I-QoL score was 93.9/110. A total of 88% of the patients reported satisfaction with the AUS. The 5-year actuarial revision-free for AUS total device was 51%. Patients for primary implant for radiation were not more likely to experience revision than non-radiation patients. Preservation of erections was reported in half of the potent patients. Transcorporal AUS cuff placement is a useful alternative procedure option for severe male UI treatment, especially in patients with a compromised urethra after prior surgery or radiation. A high continence rate was reported and implantation as first option in radiation patients should be considered.

Pulsed source ion implantation apparatus and method

DOEpatents

Leung, K.N.

1996-09-24

A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted. 16 figs.

Plasma Immersion Ion Implantation with Solid Targets for Space and Aerospace Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliveira, R. M.; Goncalves, J. A. N.; Ueda, M.

2009-01-05

This paper describes successful results obtained by a new type of plasma source, named as Vaporization of Solid Targets (VAST), for treatment of materials for space and aerospace applications, by means of plasma immersion ion implantation and deposition (PIII and D). Here, the solid element is vaporized in a high pressure glow discharge, being further ionized and implanted/deposited in a low pressure cycle, with the aid of an extra electrode. First experiments in VAST were run using lithium as the solid target. Samples of silicon and aluminum alloy (2024) were immersed into highly ionized lithium plasma, whose density was measuredmore » by a double Langmuir probe. Measurements performed with scanning electron microscopy (SEM) showed clear modification of the cross-sectioned treated silicon samples. X-ray photoelectron spectroscopy (XPS) analysis revealed that lithium was implanted/deposited into/onto the surface of the silicon. Implantation depth profiles may vary according to the condition of operation of VAST. One direct application of this treatment concerns the protection against radiation damage for silicon solar cells. For the case of the aluminum alloy, X-ray diffraction analysis indicated the appearance of prominent new peaks. Surface modification of A12024 by lithium implantation/deposition can lower the coefficient of friction and improve the resistance to fatigue of this alloy. Recently, cadmium was vaporized and ionized in VAST. The main benefit of this element is associated with the improvement of corrosion resistance of metallic substrates. Besides lithium and cadmium, VAST allows to performing PIII and D with other species, leading to the modification of the near-surface of materials for distinct purposes, including applications in the space and aerospace areas.« less

Characterization of Boron Contamination in Fluorine Implantation using Boron Trifluoride as a Source Material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmeide, Matthias; Kondratenko, Serguei

2011-01-07

Fluorine implantation process purity was considered on different types of high current implanters. It was found that implanters equipped with an indirectly heated cathode ion source show an enhanced deep boron contamination compared to a high current implanter using a cold RF-driven multicusp ion source when boron trifluoride is used for fluorine implantations. This contamination is directly related to the source technology and thus, should be considered potentially for any implanter design using hot cathode/hot filament ion source, independently of the manufacturer.The boron contamination results from the generation of double charged boron ions in the arc chamber and the subsequentmore » charge exchange reaction to single charged boron ions taking place between the arc chamber and the extraction electrode. The generation of the double charged boron ions depends mostly on the source parameters, whereas the pressure in the region between the arc chamber and the extraction electrode is mostly responsible for the charge exchange from double charged to single charged ions. The apparent mass covers a wide range, starting at mass 11. A portion of boron ions with energies of (19/11) times higher than fluorine energy has the same magnetic rigidity as fluorine beam and cannot be separated by the analyzer magnet. The earlier described charge exchange effects between the extraction electrode and the entrance to the analyzer magnet, however, generates boron beam with a higher magnetic rigidity compared to fluorine beam and cannot cause boron contamination after mass-separation.The energetic boron contamination was studied as a function of the ion source parameters, such as gas flow, arc voltage, and source magnet settings, as well as analyzing magnet aperture resolution. This allows process optimization reducing boron contamination to the level acceptable for device performance.« less

Softening due to Grain Boundary Cavity Formation and its Competition with Hardening in Helium Implanted Nanocrystalline Tungsten

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cunningham, W. Streit; Gentile, Jonathan M.; El-Atwani, Osman

The unique ability of grain boundaries to act as effective sinks for radiation damage plays a significant role in nanocrystalline materials due to their large interfacial area per unit volume. Leveraging this mechanism in the design of tungsten as a plasma-facing material provides a potential pathway for enhancing its radiation tolerance under fusion-relevant conditions. In this study, we explore the impact of defect microstructures on the mechanical behavior of helium ion implanted nanocrystalline tungsten through nanoindentation. Softening was apparent across all implantation temperatures and attributed to bubble/cavity loaded grain boundaries suppressing the activation barrier for the onset of plasticity viamore » grain boundary mediated dislocation nucleation. An increase in fluence placed cavity induced grain boundary softening in competition with hardening from intragranular defect loop damage, thus signaling a new transition in the mechanical behavior of helium implanted nanocrystalline tungsten.« less

Softening due to Grain Boundary Cavity Formation and its Competition with Hardening in Helium Implanted Nanocrystalline Tungsten

DOE PAGES

Cunningham, W. Streit; Gentile, Jonathan M.; El-Atwani, Osman; ...

2018-02-13

The unique ability of grain boundaries to act as effective sinks for radiation damage plays a significant role in nanocrystalline materials due to their large interfacial area per unit volume. Leveraging this mechanism in the design of tungsten as a plasma-facing material provides a potential pathway for enhancing its radiation tolerance under fusion-relevant conditions. In this study, we explore the impact of defect microstructures on the mechanical behavior of helium ion implanted nanocrystalline tungsten through nanoindentation. Softening was apparent across all implantation temperatures and attributed to bubble/cavity loaded grain boundaries suppressing the activation barrier for the onset of plasticity viamore » grain boundary mediated dislocation nucleation. An increase in fluence placed cavity induced grain boundary softening in competition with hardening from intragranular defect loop damage, thus signaling a new transition in the mechanical behavior of helium implanted nanocrystalline tungsten.« less

Effects of He implantation on radiation induced segregation in Cu-Au and Ni-Si alloys

NASA Astrophysics Data System (ADS)

Iwase, A.; Rehn, L. E.; Baldo, P. M.; Funk, L.

Effects of He implantation on radiation induced segregation (RIS) in Cu-Au and Ni-Si alloys were investigated using in situ Rutherford backscattering spectrometry during simultaneous irradiation with 1.5-MeV He and low-energy (100 or 400-keV) He ions at elevated temperatures. RIS during single He ion irradiation, and the effects of pre-implantation with low-energy He ions, were also studied. RIS near the specimen surface, which was pronounced during 1.5-MeV He single-ion irradiation, was strongly reduced under low-energy He single-ion irradiation, and during simultaneous irradiation with 1.5-MeV He and low-energy He ions. A similar RIS reduction was also observed in the specimens pre-implanted with low-energy He ions. The experimental results indicate that the accumulated He atoms cause the formation of small bubbles, which provide additional recombination sites for freely migrating defects.

Comparison of conventional and synchrotron-radiation-based microtomography of bone around dental implants

NASA Astrophysics Data System (ADS)

Cattaneo, Paolo M.; Dalstra, Michel; Beckmann, Felix; Donath, Tilman; Melsen, Birte

2004-10-01

This study explores the application of conventional micro tomography (μCT) and synchrotron radiation (SR) based μCT to evaluate the bone around titanium dental implants. The SR experiment was performed at beamline W2 of HASYLAB at DESY using a monochromatic X-ray beam of 50 keV. The testing material consisted of undecalcified bone segments harvested from the upper jaw of a macaca fascicularis monkey each containing a titanium dental implant. The results from the two different techniques were qualitatively compared with conventional histological sections examined under light microscopy. The SR-based μCT produced images that, especially at the bone-implant interface, are less noisy and sharper than the ones obtained with conventional μCT. For the proper evaluation of the implant-bone interface, only the SR-based μCT technique is able to display the areas of bony contact and visualize the true 3D structure of bone around dental implants correctly. This investigation shows that both conventional and SR-based μCT scanning techniques are non-destructive methods, which provide detailed images of bone. However with SR-based μCT it is possible to obtain an improved image quality of the bone surrounding dental implants, which display a level of detail comparable to histological sections. Therefore, SR-based μCT scanning could represent a valid, unbiased three-dimensional alternative to evaluate osseointegration of dental implants

Radiation control in the intensive care unit for high intensity iridium-192 brain implants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sewchand, W.; Drzymala, R.E.; Amin, P.P.

A bedside lead cubicle was designed to minimize the radiation exposure of intensive care unit staff during routine interstitial brain irradiation by removable, high intensity iridium-192. The cubicle shields the patient without restricting intensive care routines. The design specifications were confirmed by exposure measurements around the shield with an implanted anthropomorphic phantom simulating the patient situation. The cubicle reduces the exposure rate around an implant patient by as much as 90%, with the exposure level not exceeding 0.1 mR/hour/mg of radium-equivalent /sup 192/Ir. Evaluation of data accumulated for the past 3 years has shown that the exposure levels of individualmore » attending nurses are 0.12 to 0.36 mR/mg of radium-equivalent /sup 192/Ir per 12-hour shift. The corresponding range for entire nursing teams varies between 0.18 and 0.26. A radiation control index (exposure per mg of radium-equivalent /sup 192/Ir per nurse-hour) is thus defined for individual nurses and nursing teams; this index is a significant guide to the planning of nurse rotations for brain implant patients with various /sup 192/Ir loads. The bedside shield reduces exposure from /sup 192/Ir implants by a factor of about 20, as expected, and the exposure from the lower energy radioisotope iodine-125 is barely detectable.« less

Radiation effect on implanted pacemakers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pourhamidi, A.H.

1983-10-01

It was previously thought that diagnostic or therapeutic ionizing radiation did not have an adverse effect on the function of cardiac pacemakers. Recently, however, some authors have reported damaging effect of therapeutic radiation on cardiac pulse generators. An analysis of a recently-extracted pacemaker documented the effect of radiation on the pacemaker pulse generator.

Implant for in-vivo parameter monitoring, processing and transmitting

DOEpatents

Ericson, Milton N [Knoxville, TN; McKnight, Timothy E [Greenback, TN; Smith, Stephen F [London, TN; Hylton, James O [Clinton, TN

2009-11-24

The present invention relates to a completely implantable intracranial pressure monitor, which can couple to existing fluid shunting systems as well as other internal monitoring probes. The implant sensor produces an analog data signal which is then converted electronically to a digital pulse by generation of a spreading code signal and then transmitted to a location outside the patient by a radio-frequency transmitter to an external receiver. The implanted device can receive power from an internal source as well as an inductive external source. Remote control of the implant is also provided by a control receiver which passes commands from an external source to the implant system logic. Alarm parameters can be programmed into the device which are capable of producing an audible or visual alarm signal. The utility of the monitor can be greatly expanded by using multiple pressure sensors simultaneously or by combining sensors of various physiological types.

Implantable device for in-vivo intracranial and cerebrospinal fluid pressure monitoring

DOEpatents

Ericson, Milton N.; McKnight, Timothy E.; Smith, Stephen F.; Hylton, James O.

2003-01-01

The present invention relates to a completely implantable intracranial pressure monitor, which can couple to existing fluid shunting systems as well as other internal monitoring probes. The implant sensor produces an analog data signal which is then converted electronically to a digital pulse by generation of a spreading code signal and then transmitted to a location outside the patient by a radio-frequency transmitter to an external receiver. The implanted device can receive power from an internal source as well as an inductive external source. Remote control of the implant is also provided by a control receiver which passes commands from an external source to the implant system logic. Alarm parameters can be programmed into the device which are capable of producing an audible or visual alarm signal. The utility of the monitor can be greatly expanded by using multiple pressure sensors simultaneously or by combining sensors of various physiological types.

WE-FG-BRA-02: Docetaxel Eluting Brachytherapy Spacers for Local Chemo-Radiation Therapy in Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belz, J; Kumar, R; Sridhar, S

Purpose: We propose an innovative combinatorial treatment strategy of Local ChemoRadiation Therapy (LCRT) using a sustained drug delivery platform in the form of a spacer to locally radio-sensitize the prostate with Docetaxel (DTX) enabling a synergistic cure with the use of lower radiation doses. These biodegradable spacers are physically similar to the inert spacers routinely used in prostate brachytherapy but are now loaded with formulations of DTX. Methods: Spacers were loaded with ∼500µg Docetaxel (DTX) for prostate cancer studies. The implants were characterized in vitro using SEM and HPLC. The release kinetic studies were carried out in buffer (pH 6.0)more » at 37°C. Subcutaneous PC3 tumors were xenografted in nude mice. Prostate cancer studies were done with and without radiation using SARRP at 5Gy, 10Gy, and 15Gy. Drug-loaded implants were injected once intratumorally using an 18G brachytherapy needle. Results: The release study in vitro showed a highly sustained release for multiple weeks at therapeutically relevant doses. The monotherapy with local DTX spacer showed sustained tumor inhibition compared to empty implants and an equivalent DTX dose given systemically. At 40 days, 89% survival was observed for mice treated with DTX implants compared with 0% in all other treatment groups. The combined treatment with local DTX spacer and radiation (10Gy) showed the highest degree of tumor suppression (significant tumor growth inhibition by day 90). The control mice showed continuous tumor growth and were scarified by day 56. Groups of mice treated with DTX-spacer or radiation alone showed initial tumor suppression but growth continued after day 60. A larger experiment is ongoing. Conclusion: This approach provides localized delivery of the chemotherapeutic sensitizer directly to the tumor and avoids the toxicities associated with both brachytherapy and current systemic delivery of docetaxel. Sustained release of DTX is an effective chemotherapy option alone or in combination with radiation therapy.« less

The use of nomograms in LDR-HDR prostate brachytherapy.

PubMed

Pujades, Ma Carmen; Camacho, Cristina; Perez-Calatayud, Jose; Richart, José; Gimeno, Jose; Lliso, Françoise; Carmona, Vicente; Ballester, Facundo; Crispín, Vicente; Rodríguez, Silvia; Tormo, Alejandro

2011-09-01

The common use of nomograms in Low Dose Rate (LDR) permanent prostate brachytherapy (BT) allows to estimate the number of seeds required for an implant. Independent dosimetry verification is recommended for each clinical dosimetry in BT. Also, nomograms can be useful for dose calculation quality assurance and they could be adapted to High Dose Rate (HDR). This work sets nomograms for LDR and HDR prostate-BT implants, which are applied to three different institutions that use different implant techniques. Patients treated throughout 2010 till April 2011 were considered for this study. This example was chosen to be the representative of the latest implant techniques and to ensure consistency in the planning. A sufficient number of cases for both BT modalities, prescription dose and different work methodology (depending on the institution) were taken into account. The specific nomograms were built using the correlation between the prostate volume and some characteristic parameters of each BT modality, such as the source Air Kerma Strength, number of implanted seeds in LDR or total radiation time in HDR. For each institution and BT modality, nomograms normalized to the prescribed dose were obtained and fitted to a linear function. The parameters of the adjustment show a good agreement between data and the fitting. It should be noted that for each institution these linear function parameters are different, indicating that each centre should construct its own nomograms. Nomograms for LDR and HDR prostate brachytherapy are simple quality assurance tools, specific for each institution. Nevertheless, their use should be complementary to the necessary independent verification.

The use of nomograms in LDR-HDR prostate brachytherapy

PubMed Central

Camacho, Cristina; Perez-Calatayud, Jose; Richart, José; Gimeno, Jose; Lliso, Françoise; Carmona, Vicente; Ballester, Facundo; Crispín, Vicente; Rodríguez, Silvia; Tormo, Alejandro

2011-01-01

Purpose The common use of nomograms in Low Dose Rate (LDR) permanent prostate brachytherapy (BT) allows to estimate the number of seeds required for an implant. Independent dosimetry verification is recommended for each clinical dosimetry in BT. Also, nomograms can be useful for dose calculation quality assurance and they could be adapted to High Dose Rate (HDR). This work sets nomograms for LDR and HDR prostate-BT implants, which are applied to three different institutions that use different implant techniques. Material and methods Patients treated throughout 2010 till April 2011 were considered for this study. This example was chosen to be the representative of the latest implant techniques and to ensure consistency in the planning. A sufficient number of cases for both BT modalities, prescription dose and different work methodology (depending on the institution) were taken into account. The specific nomograms were built using the correlation between the prostate volume and some characteristic parameters of each BT modality, such as the source Air Kerma Strength, number of implanted seeds in LDR or total radiation time in HDR. Results For each institution and BT modality, nomograms normalized to the prescribed dose were obtained and fitted to a linear function. The parameters of the adjustment show a good agreement between data and the fitting. It should be noted that for each institution these linear function parameters are different, indicating that each centre should construct its own nomograms. Conclusions Nomograms for LDR and HDR prostate brachytherapy are simple quality assurance tools, specific for each institution. Nevertheless, their use should be complementary to the necessary independent verification. PMID:23346120

Radiotherapy and risk of implantable cardioverter-defibrillator malfunctions: experimental data from direct exposure at increasing doses.

PubMed

Zecchin, Massimo; Artico, Jessica; Morea, Gaetano; Severgnini, Mara; Bianco, Elisabetta; De Luca, Antonio; Fantasia, Anna Zorzin; Salvatore, Luca; Milan, Vittorino; Lucarelli, Matteo; Dissegna, Roberta; Cannatà, Antonio; Sinagra, Gianfranco

2018-04-01

During radiotherapy, in patients with implantable cardioverter-defibrillators (ICDs) malfunctions are considered more likely if doses more than 2 Gy reach the ICD site; however, most malfunctions occur with high-energy (>10 MV) radiations, and the risk is less defined using 6-MV linear accelerators. The purpose of the study is to experimentally evaluate the occurrence of malfunctions in ICDs radiated with a 6-MV linear accelerator at increasing photon doses. Thirty-two ICDs from all manufacturers (31 explanted and one demo) were evaluated; all devices with a sufficient battery charge underwent multiple radiations with a 6-MV photon beam reaching a cumulative dose at ICD site of 0.5, 1, 2, 3, 5 and 10 Gy and interrogated after every session. All antitachycardia therapies were left enabled; two ICDs were connected to a rhythm simulator (one simulating a complete atrioventricular block without ventricular activity) and visually monitored by external ECG and the ICD programmer during radiation. Thirteen ICDs were excluded before radiation because of battery depletion; after radiation up to the cumulative dose at the cardiac implantable electronic device site of 10 Gy, in the remaining 19 devices, programmation and battery charge remained unchanged and no switch to safety mode was observed; oversensing, pacing inhibition or inappropriate antitachycardia therapy were neither recorded nor visually observed during radiation. With a low-energy accelerator, neither malfunctions nor electromagnetic interferences were detected radiating the ICDs at doses usually reaching the ICD pocket during radiotherapy sessions. In this context, magnet application to avoid oversensing and inappropriate therapy seems, therefore, useless.

Spiral Chip Implantable Radiator and Printed Loop External Receptor for RF Telemetry in Bio-Sensor Systems

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Hall, David G.; Miranda, Felix A.

2004-01-01

The paper describes the operation of a patented wireless RF telemetry system, consisting of a bio-MEMS implantable sensor and an external hand held unit, operating over the frequency range of few hundreds of MHz. A MEMS capacitive pressure sensor integrated with a miniature inductor/antenna together constitute the implantable sensor. Signal processing circuits collocated with a printed loop antenna together form the hand held unit, capable of inductively powering and also receiving the telemetry signals from the sensor. The paper in addition, demonstrates a technique to enhance the quality factor and inductance of the inductor in the presence of a lower ground plane and also presents the radiation characteristics of the loop antenna.

Tracking Accuracy of a Real-Time Fiducial Tracking System for Patient Positioning and Monitoring in Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shchory, Tal; Schifter, Dan; Lichtman, Rinat

Purpose: In radiation therapy there is a need to accurately know the location of the target in real time. A novel radioactive tracking technology has been developed to answer this need. The technology consists of a radioactive implanted fiducial marker designed to minimize migration and a linac mounted tracking device. This study measured the static and dynamic accuracy of the new tracking technology in a clinical radiation therapy environment. Methods and Materials: The tracking device was installed on the linac gantry. The radioactive marker was located in a tissue equivalent phantom. Marker location was measured simultaneously by the radioactive trackingmore » system and by a Microscribe G2 coordinate measuring machine (certified spatial accuracy of 0.38 mm). Localization consistency throughout a volume and absolute accuracy in the Fixed coordinate system were measured at multiple gantry angles over volumes of at least 10 cm in diameter centered at isocenter. Dynamic accuracy was measured with the marker located inside a breathing phantom. Results: The mean consistency for the static source was 0.58 mm throughout the tested region at all measured gantry angles. The mean absolute position error in the Fixed coordinate system for all gantry angles was 0.97 mm. The mean real-time tracking error for the dynamic source within the breathing phantom was less than 1 mm. Conclusions: This novel radioactive tracking technology has the potential to be useful in accurate target localization and real-time monitoring for radiation therapy.« less

Tracking accuracy of a real-time fiducial tracking system for patient positioning and monitoring in radiation therapy.

PubMed

Shchory, Tal; Schifter, Dan; Lichtman, Rinat; Neustadter, David; Corn, Benjamin W

2010-11-15

In radiation therapy there is a need to accurately know the location of the target in real time. A novel radioactive tracking technology has been developed to answer this need. The technology consists of a radioactive implanted fiducial marker designed to minimize migration and a linac mounted tracking device. This study measured the static and dynamic accuracy of the new tracking technology in a clinical radiation therapy environment. The tracking device was installed on the linac gantry. The radioactive marker was located in a tissue equivalent phantom. Marker location was measured simultaneously by the radioactive tracking system and by a Microscribe G2 coordinate measuring machine (certified spatial accuracy of 0.38 mm). Localization consistency throughout a volume and absolute accuracy in the Fixed coordinate system were measured at multiple gantry angles over volumes of at least 10 cm in diameter centered at isocenter. Dynamic accuracy was measured with the marker located inside a breathing phantom. The mean consistency for the static source was 0.58 mm throughout the tested region at all measured gantry angles. The mean absolute position error in the Fixed coordinate system for all gantry angles was 0.97 mm. The mean real-time tracking error for the dynamic source within the breathing phantom was less than 1 mm. This novel radioactive tracking technology has the potential to be useful in accurate target localization and real-time monitoring for radiation therapy. Copyright © 2010 Elsevier Inc. All rights reserved.

Transcorporal artificial urinary sphincter in radiated and non - radiated compromised urethra. Assessment with a minimum 2 year follow-up

PubMed Central

Long, Erwann Le; Rebibo, John David; Nouhaud, Francois Xavier; Grise, Philippe

2016-01-01

ABSTRACT Purpose to assess the efficacy of transcorporal artificial urinary sphincter (AUS) implantation on continence for male stress urinary incontinence in cases of prior surgical treatment or/and radiation failure, and as a first option in radiation patients. Materials and Methods From March 2007 to August 2012, 37 male patients were treated with transcorporal AUS AMS™ 800. Twelve patients had primary placement of transcorporal cuff, a surgical option due to a previous history of radiation and 25 patients had secondary procedure after failure of AUS or urinary incontinence surgery. Functional urinary outcomes were assessed by daily pad use, 24-hour Pad-test and ICIQ-SF questionnaire. Quality of life and satisfaction were assessed based on I-QoL and PGI-I questionnaires. Results After a median of 32 months, the continence rate (0 to 1 pad) was 69.7%. Median pad test was 17.5g (0-159), mean ICIQ-SF score was 7.3/21 (±5.4) and mean I-QoL score was 93.9/110. A total of 88% of the patients reported satisfaction with the AUS. The 5-year actuarial revision-free for AUS total device was 51%. Patients for primary implant for radiation were not more likely to experience revision than non-radiation patients. Preservation of erections was reported in half of the potent patients. Conclusions Transcorporal AUS cuff placement is a useful alternative procedure option for severe male UI treatment, especially in patients with a compromised urethra after prior surgery or radiation. A high continence rate was reported and implantation as first option in radiation patients should be considered. PMID:27286112

Back-side hydrogenation technique for defect passivation in silicon solar cells

DOEpatents

Sopori, Bhushan L.

1994-01-01

A two-step back-side hydrogenation process includes the steps of first bombarding the back side of the silicon substrate with hydrogen ions with intensities and for a time sufficient to implant enough hydrogen atoms into the silicon substrate to potentially passivate substantially all of the defects and impurities in the silicon substrate, and then illuminating the silicon substrate with electromagnetic radiation to activate the implanted hydrogen, so that it can passivate the defects and impurities in the substrate. The illumination step also annihilates the hydrogen-induced defects. The illumination step is carried out according to a two-stage illumination schedule, the first or low-power stage of which subjects the substrate to electromagnetic radiation that has sufficient intensity to activate the implanted hydrogen, yet not drive the hydrogen from the substrate. The second or high-power illumination stage subjects the substrate to higher intensity electromagnetic radiation, which is sufficient to annihilate the hydrogen-induced defects and sinter/alloy the metal contacts.

Back-side hydrogenation technique for defect passivation in silicon solar cells

DOEpatents

Sopori, B.L.

1994-04-19

A two-step back-side hydrogenation process includes the steps of first bombarding the back side of the silicon substrate with hydrogen ions with intensities and for a time sufficient to implant enough hydrogen atoms into the silicon substrate to potentially passivate substantially all of the defects and impurities in the silicon substrate, and then illuminating the silicon substrate with electromagnetic radiation to activate the implanted hydrogen, so that it can passivate the defects and impurities in the substrate. The illumination step also annihilates the hydrogen-induced defects. The illumination step is carried out according to a two-stage illumination schedule, the first or low-power stage of which subjects the substrate to electromagnetic radiation that has sufficient intensity to activate the implanted hydrogen, yet not drive the hydrogen from the substrate. The second or high-power illumination stage subjects the substrate to higher intensity electromagnetic radiation, which is sufficient to annihilate the hydrogen-induced defects and sinter/alloy the metal contacts. 3 figures.

SU-F-T-653: Radiation Exposure from Cs-131 Permanent Seed Implants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giaddui, T; Hardin, M; To, D

Purpose: Permanent seed implants have traditionally been used to treat prostate, lung and head or neck cancers using I-125 and Pd-103. Cs-131, which has higher dose rate is being used to treat brain, head and/or neck cancers in our clinic, therefore, we chose to monitor the dose received by surgeons during the extensive procedure. The aims of this work are to assess the level of radiation exposure to surgeons and the instantaneous exposure at bedside and 1 m from patients. Methods: Ten patients received Cs-131 implants for recurrent brain,head and/or neck cancer; the median implanted activity, number of implanted seedsmore » and prescription dose at 0.5 cm from the perpendicular plane of the implant were: 54.3 mCi (14.52 – 77); 19 (4 – 24) and 60 Gy (range 42 – 60) respectively. Radiation exposure was recorded at bedside and 1 m from the patient using Victoreen ion chamber (Fluke Biomedical, Cleveland, OH). Exposure to surgeons was measured using TLD (Mirion Technologies (GDS), Inc., USA). Results: The median equivalent dose rate at 1 m and bedside immediately following implantation were 1.49×10-2 mSv/h (8.77×10-3–2.63×10-2) and 7.76×10-2 mSv/h (3.1×10-2– 1.53×10-1) respectively. Median equivalent dose to surgeons’ hands was 0.60 mSv (0.33 – 1.48) and no doses were detected for whole-body. Surgical reconstruction for one patient was performed 71 days post-implant and resulted in zero exposure to surgeons. Conclusion: The recorded exposure rates were low when compared with the literature. Post procedure surveys at bed site and 1 m indicated that all patients were within safe limits for discharge (< 0.05 mSv/h at 1 m). However, as a precautionary measure, patients were advised to avoid direct contact with children and pregnant women within four weeks of the implant and stay at least at 3 ft from other people. Surgeons doses were well within occupational dose limits.« less

Silkworm Gut Fiber of Bombyx mori as an Implantable and Biocompatible Light-Diffusing Fiber

PubMed Central

Cenis, Jose Luis; Aznar-Cervantes, Salvador D.; Lozano-Pérez, Antonio Abel; Rojo, Marta; Muñoz, Juan; Meseguer-Olmo, Luis; Arenas, Aurelio

2016-01-01

This work describes a new approach to the delivery of light in deeper tissues, through a silk filament that is implantable, biocompatible, and biodegradable. In the present work, silkworm gut fibers (SGFs) of Bombyx mori L., are made by stretching the silk glands. Morphological, structural, and optical properties of the fibers have been characterized and the stimulatory effect of red laser light diffused from the fiber was assayed in fibroblast cultures. SGFs are formed by silk fibroin (SF) mainly in a β-sheet conformation, a stable and non-soluble state in water or biological fluids. The fibers showed a high degree of transparency to visible and infrared radiation. Using a red laser (λ = 650 nm) as source, the light was efficiently diffused along the fiber wall, promoting a significant increment in the cell metabolism 5 h after the irradiation. SGFs have shown their excellent properties as light-diffusing optical fibers with a stimulatory effect on cells. PMID:27438824

Current State and Future Perspectives of Energy Sources for Totally Implantable Cardiac Devices.

PubMed

Bleszynski, Peter A; Luc, Jessica G Y; Schade, Peter; PhilLips, Steven J; Tchantchaleishvili, Vakhtang

There is a large population of patients with end-stage congestive heart failure who cannot be treated by means of conventional cardiac surgery, cardiac transplantation, or chronic catecholamine infusions. Implantable cardiac devices, many designated as destination therapy, have revolutionized patient care and outcomes, although infection and complications related to external power sources or routine battery exchange remain a substantial risk. Complications from repeat battery replacement, power failure, and infections ultimately endanger the original objectives of implantable biomedical device therapy - eliminating the intended patient autonomy, affecting patient quality of life and survival. We sought to review the limitations of current cardiac biomedical device energy sources and discuss the current state and trends of future potential energy sources in pursuit of a lifelong fully implantable biomedical device.

Progress and trends in patients' mindset on dental implants. I: level of information, sources of information and need for patient information.

PubMed

Pommer, Bernhard; Zechner, Werner; Watzak, Georg; Ulm, Christian; Watzek, Georg; Tepper, Gabor

2011-02-01

Little is known about the level of information on implant dentistry in the public. A representative opinion poll on dental implants in the Austrian population was published in 2003 (Clinical Oral Implants Research 14:621-642). Seven years later, the poll was rerun to assess the up-to-date information level and evaluate recent progress and trends in patients' mindset on dental implants. One thousand adults--representative for the Austrian population--were presented with a total of 19 questionnaire items regarding the level and the sources of information about dental implants as well as the subjective and objective need for patient information. Compared with the survey of 2003, the subjective level of patient information about implant dentistry has significantly increased in the Austrian population. The patients' implant awareness rate was 79%. The objective level of general knowledge about dental implants was still all but satisfactory revealing unrealistic patient expectations. Three-quarters trusted their dentists for information about dental implants, while one-quarter turned to the media. The patients' wish for high-quality implant restorations was significantly higher than in 2003, yet the majority felt that only specialists should perform implant dentistry. This representative survey reveals that dentists are still the main source of patient information, but throws doubt on the quality of their public relations work. Dentists must improve communication strategies to provide their patients with comprehensible, legally tenable information on dental implants and bridge information gaps in the future. © 2010 John Wiley & Sons A/S.

Radiosensitizing Pancreatic Cancer Xenografts by an Implantable Micro-Oxygen Generator.

PubMed

Cao, Ning; Song, Seung Hyun; Maleki, Teimour; Shaffer, Michael; Stantz, Keith M; Cao, Minsong; Kao, Chinghai; Mendonca, Marc S; Ziaie, Babak; Ko, Song-Chu

2016-04-01

Over the past decades, little progress has been made to improve the extremely low survival rates in pancreatic cancer patients. Extreme hypoxia observed in pancreatic tumors contributes to the aggressive and metastatic characteristics of this tumor and can reduce the effectiveness of conventional radiation therapy and chemotherapy. In an attempt to reduce hypoxia-induced obstacles to effective radiation treatment, we used a novel device, the implantable micro-oxygen generator (IMOG), for in situ tumor oxygenation. After subcutaneous implantation of human pancreatic xenograft tumors in athymic rats, the IMOG was wirelessly powered by ultrasonic waves, producing 30 μA of direct current (at 2.5 V), which was then utilized to electrolyze water and produce oxygen within the tumor. Significant oxygen production by the IMOG was observed and corroborated using the NeoFox oxygen sensor dynamically. To test the radiosensitization effect of the newly generated oxygen, the human pancreatic xenograft tumors were subcutaneously implanted in nude mice with either a functional or inactivated IMOG device. The tumors in the mice were then exposed to ultrasonic power for 10 min, followed by a single fraction of 5 Gy radiation, and tumor growth was monitored thereafter. The 5 Gy irradiated tumors containing the functional IMOG exhibited tumor growth inhibition equivalent to that of 7 Gy irradiated tumors that did not contain an IMOG. Our study confirmed that an activated IMOG is able to produce sufficient oxygen to radiosensitize pancreatic tumors, enhancing response to single-dose radiation therapy.

Radiation therapy of primary vaginal carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nori, D.; Hilaris, B.S.; Stanimir, G.

1983-10-01

Primary carcinoma of the vagina is rare, constituting only 1 to 2% of all neoplasms arising in the female genital tract. From 1950-1974, 36 patients with carcinoma of the vagina were treated with radiation at Memorial Sloan-Kettering Cancer Center (MSKCC); 35 (96%) had epidermoid carcinoma and one patient (4%) had adenocarcinoma. These patients were staged according to FIGO. Fourteen patients (39%) were Stage I; six patients (17%) were Stage II; three patients (8%) were Stage III; and 13 patients (36%) were Stage IV. Nine patients (25%) were treated with external radiation and interstitial implant; seven patients (20%) were treated withmore » interstitial implant alone; nine patients (25%) were treated with external radiation alone and 11 patients (30%) with external radiation and intracavitary radiation. The five year NED survival was 71% in Stage I, 66% in Stage II, 33% in Stage III and 0% in Stage IV. This paper discusses radiotherapy management of primary carcinoma of the vagina.« less

Radiation Hardened Silicon-on-Insulator Structures with N+ Ion Modified Buried SiO2 Layer

NASA Astrophysics Data System (ADS)

Tyschenko, I. E.; Popov, V. P.

2009-12-01

Radiation-resistant silicon-on-insulator structures were produced by N+ ion implantation into thermally grown SiO2 film and subsequent hydrogen transfer of the Si layer to the nitrogen-implanted substrate under conditions of vacuum wafer bonding. Accumulation of the carriers in the buried SiO2 was investigated as a function of fluence of nitrogen ions in the range (1-6)×1015 cm2 and as a function of total radiation dose ranging from 104 to 107 rad (Si). It was found that the charge generated near the nitrided bonding interface was reduced by a factor of four compared to the thermal SiO2/Si interface.

Displacement damage dose and implantation temperature effects on the trapping and release of deuterium implanted into SiC

NASA Astrophysics Data System (ADS)

Muñoz, P.; García-Cortés, I.; Sánchez, F. J.; Moroño, A.; Malo, M.; Hodgson, E. R.

2017-09-01

Radiation damage to flow channel insert (FCI) materials is an important issue for the concept of dual-coolant blanket development in future fusion devices. Silicon Carbide (SiC) is one of the most suitable materials for FCI. Because of the severe radiation environment and exposure to tritium during operation it is of fundamental importance to study hydrogen isotope trapping and release in these materials. Here the trapping, detrapping, and diffusion of deuterium implanted into SiC is studied in correlation with pre- and post-damage induced under different conditions. For this, SiC samples are pre-damaged with 50 keV Ne+ ions at different temperatures (20, 200, 450, 700 °C) to different damage doses (1, 3.6, 7 dpa). Next, deuterium is introduced into the samples at 450 °C by ion implantation at 7 keV. The implanted deuterium retained in the sample is analysed using secondary ion mass spectrometry (SIMS) and thermo-stimulated desorption (TSD) measurements. The results indicate that with increasing neon damage dose, the maximum deuterium desorption occurs at higher temperatures. In contrast, when increasing neon implantation temperature for a fixed dose, the maximum deuterium desorption release temperature decreases. It is interpreted that the neon bombardment produces thermally stable traps for hydrogen isotopes and the stability of this damage increases with neon pre-implantation dose. A decrease of the trapping of implanted deuterium is also observed to occur due to damage recovery by thermal annealing during pre-implantation at the higher temperatures. Finally, direct particle bombardment induced deuterium release is also observed.

Modification of anti-bacterial surface properties of textile polymers by vacuum arc ion source implantation

NASA Astrophysics Data System (ADS)

Nikolaev, A. G.; Yushkov, G. Yu.; Oks, E. M.; Oztarhan, A.; Akpek, A.; Hames-Kocabas, E.; Urkac, E. S.; Brown, I. G.

2014-08-01

Ion implantation provides an important technology for the modification of material surface properties. The vacuum arc ion source is a unique instrument for the generation of intense beams of metal ions as well as gaseous ions, including mixed metal-gas beams with controllable metal:gas ion ratio. Here we describe our exploratory work on the application of vacuum arc ion source-generated ion beams for ion implantation into polymer textile materials for modification of their biological cell compatibility surface properties. We have investigated two specific aspects of cell compatibility: (i) enhancement of the antibacterial characteristics (we chose to use Staphylococcus aureus bacteria) of ion implanted polymer textile fabric, and (ii) the "inverse" concern of enhancement of neural cell growth rate (we chose Rat B-35 neuroblastoma cells) on ion implanted polymer textile. The results of both investigations were positive, with implantation-generated antibacterial efficiency factor up to about 90%, fully comparable to alternative conventional (non-implantation) approaches and with some potentially important advantages over the conventional approach; and with enhancement of neural cell growth rate of up to a factor of 3.5 when grown on suitably implanted polymer textile material.

Investigation of the stability of glass-ceramic composites containing CeTi 2 O 6 and CaZrTi 2 O 7 after ion implantation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paknahad, Elham; Grosvenor, Andrew P.

Glass-ceramic composite materials have been investigated for nuclear waste sequestration applications due to their ability to incorporate large amounts of radioactive waste elements. A key property that needs to be understood when developing nuclear waste sequestration materials is how the structure of the material responds to radioactive decay of nuclear waste elements, which can be simulated by high energy ion implantation. Borosilicate glass-ceramic composites containing brannerite-type (CeTi2O6) or zirconolite-type (CaZrTi2O7) oxides were synthesized at different annealing temperatures and investigated after being implanted with high-energy Au ions to mimic radiation induced structural damage. Backscattered electron (BSE) images were collected to investigatemore » the interaction of the brannerite crystallites with the glass matrix before and after implantation and showed that the morphology of the crystallites in the composite materials were not affected by radiation damage. Surface sensitive Ti K-edge glancing angle XANES spectra collected from the implanted composite materials showed that the structures of the CeTi2O6 and CaZrTi2O7 ceramics were damaged as a result of implantation; however, analysis of Si L2,3-edge XANES spectra indicated that the glass matrix was not affected by ion implantation.« less

Investigation of the stability of glass-ceramic composites containing CeTi2O6 and CaZrTi2O7 after ion implantation

NASA Astrophysics Data System (ADS)

Paknahad, Elham; Grosvenor, Andrew P.

2017-12-01

Glass-ceramic composite materials have been investigated for nuclear waste sequestration applications due to their ability to incorporate large amounts of radioactive waste elements. A key property that needs to be understood when developing nuclear waste sequestration materials is how the structure of the material responds to radioactive decay of nuclear waste elements, which can be simulated by high energy ion implantation. Borosilicate glass-ceramic composites containing brannerite-type (CeTi2O6) or zirconolite-type (CaZrTi2O7) oxides were synthesized at different annealing temperatures and investigated after being implanted with high-energy Au ions to mimic radiation induced structural damage. Backscattered electron (BSE) images were collected to investigate the interaction of the brannerite crystallites with the glass matrix before and after implantation and showed that the morphology of the crystallites in the composite materials were not affected by radiation damage. Surface sensitive Ti K-edge glancing angle XANES spectra collected from the implanted composite materials showed that the structures of the CeTi2O6 and CaZrTi2O7 ceramics were damaged as a result of implantation; however, analysis of Si L2,3-edge XANES spectra indicated that the glass matrix was not affected by ion implantation.

Ultracompact Implantable Design With Integrated Wireless Power Transfer and RF Transmission Capabilities.

PubMed

Sun, Guilin; Muneer, Badar; Li, Ying; Zhu, Qi

2018-04-01

This paper presents an ultracompact design of biomedical implantable devices with integrated wireless power transfer (WPT) and RF transmission capabilities for implantable medical applications. By reusing the spiral coil in an implantable device, both RF transmission and WPT are realized without the performance degradation of both functions in ultracompact size. The complete theory of WPT based on magnetic resonant coupling is discussed and the design methodology of an integrated structure is presented in detail, which can guide the design effectively. A system with an external power transmitter and implantable structure is fabricated to validate the proposed approach. The experimental results show that the implantable structure can receive power wirelessly at 39.86 MHz with power transfer efficiency of 47.2% and can also simultaneously radiate at 2.45 GHz with an impedance bandwidth of 10.8% and a gain of -15.71 dBi in the desired direction. Furthermore, sensitivity analyses are carried out with the help of experiment and simulation. The results reveal that the system has strong tolerance to the nonideal conditions. Additionally, the specific absorption rate distribution is evaluated in the light of strict IEEE standards. The results reveal that the implantable structure can receive up to 115 mW power from an external transmitter and radiate 6.4 dB·m of power safely.

Transperineal ultrasound-guided implantation of electromagnetic transponders in the prostatic fossa for localization and tracking during external beam radiation therapy.

PubMed

Garsa, Adam A; Verma, Vivek; Michalski, Jeff M; Gay, Hiram A

2014-01-01

To describe a transperineal ultrasound-guided technique for implantation of electromagnetic transponders into the prostatic fossa. Patients were placed in the dorsal lithotomy position, and local anesthetic was administered. On ultrasound, the bladder, urethra, vesicourethral anastomosis, rectum, and the prostatic fossa were carefully identified. Three transponders were implanted into the prostatic fossa under ultrasound guidance in a triangular configuration and implantation was verified by fluoroscopy. Patients underwent computed tomography (CT) simulation approximately 1 week later. All patients in this study were subsequently treated with intensity modulated radiation therapy (IMRT) to the prostatic fossa. From 2008 to 2012, 180 patients received transperineal implantation of electromagnetic transponders into the prostatic fossa and subsequently received IMRT. There were no cases of severe hematuria or rectal bleeding requiring intervention. There were no grade 3 or 4 toxicities. Three patients (1.7%) had a transponder missing on the subsequent CT simulation. Thirteen patients (7.3%) had transponder migration with a geometric residual that exceeded 2 mm for 3 consecutive days (5.6%) or rotation that exceeded 10 degrees for 5 consecutive days (1.7%). These patients underwent a resimulation CT scan to identify the new transponder coordinates. A transperineal technique for implantation of electromagnetic transponders into the prostatic fossa is safe and well tolerated, with no severe toxicity after implantation. There is a low rate of transponder loss or migration.

Optima HD Imax: Molecular Implant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tieger, D. R.; Splinter, P. R.; Hsieh, T. J.

2008-11-03

Molecular implantation offers semiconductor device manufacturers multiple advantages over traditional high current ion implanters. The dose multiplication due to implanting more than one atom per molecule and the transport of beams at higher energies relative to the effective particle energies result in significant throughput enhancements without risk of energy contamination. The Optima HD Imax is introduced with molecular implant capability and the ability to reach up to 4.2 keV effective {sup 11}B from octadecaborane (B{sub 18}H{sub 22}). The ion source and beamline are optimized for molecular species ionization and transport. The beamline is coupled to the Optima HD mechanically scannedmore » endstation. The use of spot beam technology with ionized molecules maximizes the throughput potential and produces uniform implants with fast setup time and with superior angle control. The implanter architecture is designed to run multiple molecular species; for example, in addition to B{sub 18}H{sub 22} the system is capable of implanting carbon molecules for strain engineering and shallow junction engineering. Source lifetime data and typical operating conditions are described both for high dose, memory applications such as dual poly gate as well as lower energy implants for source drain extension and contact implants. Throughputs have been achieved in excess of 50 wafers per hour at doses up to 1x10{sup 16} ions/cm{sup 2} and for energies as low as 1 keV.« less

Effects of radiation from a radiofrequency identification (RFID) microchip on human cancer cells.

PubMed

Lai, Henry C; Chan, Ho Wing; Singh, Narendra P

2016-01-01

Radiofrequency identification (RFID) microchips are used to remotely identify objects, e.g. an animal in which a chip is implanted. A passive RFID microchip absorbs energy from an external source and emits a radiofrequency identification signal which is then decoded by a detector. In the present study, we investigated the effect of the radiofrequency energy emitted by a RFID microchip on human cancer cells. Molt-4 leukemia, BT474 breast cancer, and HepG2 hepatic cancer cells were exposed in vitro to RFID microchip-emitted radiofrequency field for 1 h. Cells were counted before and after exposure. Effects of pretreatment with the spin-trap compound N-tert-butyl-alpha-phenylnitrone or the iron-chelator deferoxamine were also investigated. Results We found that the energy effectively killed/retarded the growth of the three different types of cancer cells, and the effect was blocked by the spin-trap compound or the iron-chelator, whereas an inactive microchip and energy from the external source had no significant effect on the cells. Conclusions Data of the present study suggest that radiofrequency field from the microchip affects cancer cells via the Fenton Reaction. Implantation of RFID microchips in tumors may provide a new method for cancer treatment.

Influence of ion source configuration and its operation parameters on the target sputtering and implantation process.

PubMed

Shalnov, K V; Kukhta, V R; Uemura, K; Ito, Y

2012-06-01

In the work, investigation of the features and operation regimes of sputter enhanced ion-plasma source are presented. The source is based on the target sputtering with the dense plasma formed in the crossed electric and magnetic fields. It allows operation with noble or reactive gases at low pressure discharge regimes, and, the resulting ion beam is the mixture of ions from the working gas and sputtering target. Any conductive material, such as metals, alloys, or compounds, can be used as the sputtering target. Effectiveness of target sputtering process with the plasma was investigated dependently on the gun geometry, plasma parameters, and the target bias voltage. With the applied accelerating voltage from 0 to 20 kV, the source can be operated in regimes of thin film deposition, ion-beam mixing, and ion implantation. Multi-component ion beam implantation was applied to α-Fe, which leads to the surface hardness increasing from 2 GPa in the initial condition up to 3.5 GPa in case of combined N(2)-C implantation. Projected range of the implanted elements is up to 20 nm with the implantation energy 20 keV that was obtained with XPS depth profiling.

Radiation- and reference base-free navigation procedure for placement of instruments and implants: application to retrograde drilling of osteochondral lesions of the knee joint.

PubMed

Müller, Matthias; Gras, Florian; Marintschev, Ivan; Mückley, Thomas; Hofmann, Gunter O

2009-01-01

A novel, radiation- and reference base-free procedure for placement of navigated instruments and implants was developed and its practicability and precision in retrograde drillings evaluated in an experimental setting. Two different guidance techniques were used: One experimental group was operated on using the radiation- and reference base-free navigation technique (Fluoro Free), and the control group was operated on using standard fluoroscopy for guidance. For each group, 12 core decompressions were simulated by retrograde drillings in different artificial femurs following arthroscopic determination of the osteochondral lesions. The final guide-wire position was evaluated by postoperative CT analysis using vector calculation. High precision was achieved in both groups, but operating time was significantly reduced in the navigated group as compared to the control group. This was due to a 100% first-pass accuracy of drilling in the navigated group; in the control group a mean of 2.5 correction maneuvers per drilling were necessary. Additionally, the procedure was free of radiation in the navigated group, whereas 17.2 seconds of radiation exposure time were measured in the fluoroscopy-guided group. The developed Fluoro Free procedure is a promising and simplified approach to navigating different instruments as well as implants in relation to visually or tactilely placed pointers or objects without the need for radiation exposure or invasive fixation of a dynamic reference base in the bone.

Optimizing Results of Postmastectomy Radiation Therapy Utilizing the Latissimus Dorsi Flap and Tissue Expander Technique: A Single-Center Experience

PubMed Central

Chevrollier, Guillaume S.; Greaney, Patrick J.; Jenkins, Matthew P.; Copit, Steven E.

2017-01-01

Objective: Postmastectomy radiation therapy is a well-established risk factor for complications after breast reconstruction. Even if the surgeon has a suspicion that radiation therapy may be needed, it may be beneficial to place tissue expanders during the mastectomy procedure as a temporizing measure, complete radiation therapy, and then reconstruct the breast with a latissimus flap. The purpose of this study was to examine the complication rates of the latissimus dorsi flap as compared with the complication rates of implant-based reconstruction in the setting of radiation therapy. Methods: A 16-year retrospective chart review from 2000 to 2016 was conducted. All patients who underwent temporizing tissue expander placement for radiotherapy with subsequent latissimus flap reconstruction were included in the study. Patients who did not follow up for implant exchange were excluded from the study. Results: Fifty-five patients were identified with an average age of 46.0 years (range, 27-67 years) and an average body mass index of 24.2 (range, 18.9-31.9). Five patients (9.1%) developed capsular contractures amenable to surgical intervention. One patient (1.8%) developed infection of the tissue expander, requiring removal. There were no incidences of flap failure or wound dehiscence. The average follow-up after latissimus flap reconstruction was 25.3 months (range, 3.7-121.6 months). Conclusions: We feel that the latissimus dorsi flap after postmastectomy radiation therapy represents the preferred implant-based reconstruction option to consider when the need for postmastectomy radiation therapy is anticipated. The latissimus dorsi flap remains a safe, effective solution to postmastectomy radiation therapy that every plastic surgeon should offer. PMID:29308108

Optimizing Results of Postmastectomy Radiation Therapy Utilizing the Latissimus Dorsi Flap and Tissue Expander Technique: A Single-Center Experience.

PubMed

Mohiuddin, Waseem; Chevrollier, Guillaume S; Greaney, Patrick J; Jenkins, Matthew P; Copit, Steven E

2017-01-01

Objective: Postmastectomy radiation therapy is a well-established risk factor for complications after breast reconstruction. Even if the surgeon has a suspicion that radiation therapy may be needed, it may be beneficial to place tissue expanders during the mastectomy procedure as a temporizing measure, complete radiation therapy, and then reconstruct the breast with a latissimus flap. The purpose of this study was to examine the complication rates of the latissimus dorsi flap as compared with the complication rates of implant-based reconstruction in the setting of radiation therapy. Methods: A 16-year retrospective chart review from 2000 to 2016 was conducted. All patients who underwent temporizing tissue expander placement for radiotherapy with subsequent latissimus flap reconstruction were included in the study. Patients who did not follow up for implant exchange were excluded from the study. Results: Fifty-five patients were identified with an average age of 46.0 years (range, 27-67 years) and an average body mass index of 24.2 (range, 18.9-31.9). Five patients (9.1%) developed capsular contractures amenable to surgical intervention. One patient (1.8%) developed infection of the tissue expander, requiring removal. There were no incidences of flap failure or wound dehiscence. The average follow-up after latissimus flap reconstruction was 25.3 months (range, 3.7-121.6 months). Conclusions: We feel that the latissimus dorsi flap after postmastectomy radiation therapy represents the preferred implant-based reconstruction option to consider when the need for postmastectomy radiation therapy is anticipated. The latissimus dorsi flap remains a safe, effective solution to postmastectomy radiation therapy that every plastic surgeon should offer.

Influence of Au ions irradiation damage on helium implanted tungsten

NASA Astrophysics Data System (ADS)

Kong, Fanhang; Qu, Miao; Yan, Sha; Cao, Xingzhong; Peng, Shixiang; Zhang, Ailin; Xue, Jianming; Wang, Yugang; Zhang, Peng; Wang, Baoyi

2017-10-01

The damages of implanted helium ions together with energetic neutrons in tungsten is concerned under the background of nuclear fusion related materials research. Helium is lowly soluble in tungsten and has high binding energy with vacancy. In present work, noble metal Au ions were used to study the synergistic effect of radiation damage and helium implantation. Nano indenter and the Doppler broaden energy spectrum of positron annihilation analysis measurements were used to research the synergy of radiation damage and helium implantation in tungsten. In the helium fluence range of 4.8 × 1015 cm-2-4.8 × 1016 cm-2, vacancies played a role of trappers only at the very beginning of bubble nucleation. The size and density is not determined by vacancies, but the effective capture radius between helium bubbles and scattered helium atoms. Vacancies were occupied by helium bubbles even at the lowest helium fluence, leaving dislocations and helium bubbles co-exist in tungsten materials.

Bragg-Fresnel optics: New field of applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snigirev, A.

Bragg-Fresnel Optics shows excellent compatibility with the third generation synchrotron radiation sources such as ESRF and is capable of obtaining monochromatic submicron focal spots with 10{sup 8}-10{sup 9} photons/sec in an energy bandwidth of 10{sup -4}-10{sup -6} and in a photon energy range between 2-100 keV. New types of Bragg-Fresnel lenses like modified, ion implanted, bent and acoustically modulated were tested. Microprobe techniques like microdiffraction and microfluorescence based on Bragg-Fresnel optics were realised at the ESRF beamlines. Excellent parameters of the X-ray beam at the ESRF in terms of low emittance and quite small angular source size allow for Bragg-Fresnelmore » optics to occupy new fields of applications such as high resolution diffraction, holography, interferometry and phase contrast imaging.« less

Preclinical Testing of Combination Therapy for Malignant Tumors Arising from Neurofibromas

DTIC Science & Technology

2012-06-01

tested the influence of local ionizing radiation in NF90.8 and sNF96.2 cells implanted in the left and right flank in female nude mice. Ten days... local ionizing radiation (10 Gy) in MPNST tumor growth in xenograft implanted nude mice. Female nude mice bearing NF90.8 tumor in the right flank...0.96   Rosiglitazone     PPAR  gamma  agonist     576.2/0.84     1150/0.94     684.5/0.89   DCA     pyruvate

Silicon metal-semiconductor-metal photodetector

DOEpatents

Brueck, Steven R. J.; Myers, David R.; Sharma, Ashwani K.

1997-01-01

Silicon MSM photodiodes sensitive to radiation in the visible to near infrared spectral range are produced by altering the absorption characteristics of crystalline Si by ion implantation. The implantation produces a defected region below the surface of the silicon with the highest concentration of defects at its base which acts to reduce the contribution of charge carriers formed below the defected layer. The charge carriers generated by the radiation in the upper regions of the defected layer are very quickly collected between biased Schottky barrier electrodes which form a metal-semiconductor-metal structure for the photodiode.

Silicon metal-semiconductor-metal photodetector

DOEpatents

Brueck, Steven R. J.; Myers, David R.; Sharma, Ashwani K.

1995-01-01

Silicon MSM photodiodes sensitive to radiation in the visible to near infrared spectral range are produced by altering the absorption characteristics of crystalline Si by ion implantation. The implantation produces a defected region below the surface of the silicon with the highest concentration of defects at its base which acts to reduce the contribution of charge carriers formed below the defected layer. The charge carriers generated by the radiation in the upper regions of the defected layer are very quickly collected between biased Schottky barrier electrodes which form a metal-semiconductor-metal structure for the photodiode.

Modification of the crystal structure of gadolinium gallium garnet by helium ion irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ostafiychuk, B. K.; Yaremiy, I. P., E-mail: yaremiy@rambler.ru; Yaremiy, S. I.

2013-12-15

The structure of gadolinium gallium garnet (GGG) single crystals before and after implantation by He{sup +} ions has been investigated using high-resolution X-ray diffraction methods and the generalized dynamic theory of X-ray scattering. The main types of growth defects in GGG single crystals and radiation-induced defects in the ion-implanted layer have been determined. It is established that the concentration of dislocation loops in the GGG surface layer modified by ion implantation increases and their radius decreases with an increase in the implantation dose.

Radiation and depression associated with complications of tissue expander reconstruction.

PubMed

Chuba, Paul J; Stefani, William A; Dul, Carrie; Szpunar, Susan; Falk, Jeffrey; Wagner, Rachael; Edhayan, Elango; Rabbani, Anna; Browne, Cynthia H; Aref, Amr

2017-08-01

Rates of implant failure, wound healing delay, and infection are higher in patients having radiation therapy (RT) after tissue expander (TE) and permanent implant reconstruction. We investigated pretreatment risk factors for TE implant complications. 127 breast cancer patients had TE reconstruction and radiation. For 85 cases of bilateral TE reconstruction, the non-irradiated breast provided an internal control. Comparison of differences in means for continuous variables used analysis of variance, then multiple pairwise comparisons with Bonferroni correction of p value. Mean age was 53 ± 10.1 years with 14.6% African-American. Twelve (9.4%) were BRCA positive (9 BRCA1, 4 BRCA2, 1 Both). Complications were: Grade 0 (no complication; 43.9%), Grade 1 (tightness and/or drifting of implant or Baker Grade II capsular contracture; 30.9%), Grade 2 (infection, hypertrophic scarring, or incisional necrosis; 9.8%), Grade 3 (Baker Grade III capsular contracture, wound dehiscence, or impending exposure of implant; 5.7%), Grade 4 (implant failure, exchange of implant, or Baker Grade IV capsular contracture; 9.8%). 15.3% (19 cases) experienced Grade 3 or 4 complication and 9.8% (12 cases) had Grade 4 complication. Considering non-irradiated breasts, there were two (1.6%) Grade 3-4 complications. For BMI, there was no significant difference by category as defined by the CDC (p = 0.91). Patients with depression were more likely to experience Grade 3 or 4 complication (29.4 vs 13.2%; p = 0.01). Using multiple logistic regression to predict the probability of a Grade 3 or 4 complications in patients with depression were found to be 4.2 times more likely to have a Grade 3 or 4 complication (OR = 4.2, p = 0.03). Higher rates of TE reconstruction complications are expected in patients receiving radiotherapy. An unexpected finding was that patients reporting medical history of depression showed statistically significant increase in complication rates.

Hand Held Device for Wireless Powering and Interrogation of Biomems Sensors and Actuators

NASA Technical Reports Server (NTRS)

Simons, Rainee N (Inventor); Miranda, Felix Antonio (Inventor)

2007-01-01

A compact, hand-held device for wireless powering, interrogation and data retrieval from at least one implanted sensor. The hand-held device includes an antenna for powering an implanted sensor and for receiving data from the implanted sensor to the hand-held device for at least one of storage, display or analysis. The hand-held device establishes electromagnetic coupling with a low radiating radio frequency power inductor in the implanted sensor at a predefined separation and the antenna geometry allows for the antenna to power, interrogate and retrieve data from the implanted sensor without strapping the hand-held device to a human body housing the implanted sensor The hand-held device optionally allows for activation of the implanted sensor only during interrogation and data retrieval.

Optoelectronic microdevices for combined phototherapy

NASA Astrophysics Data System (ADS)

Zharov, Vladimir P.; Menyaev, Yulian A.; Hamaev, V. A.; Antropov, G. M.; Waner, Milton

2000-03-01

In photomedicine in some of cases radiation delivery to local zones through optical fibers can be changed for the direct placing of tiny optical sources like semiconductor microlasers or light diodes in required zones of ears, nostrils, larynx, nasopharynx cochlea or alimentary tract. Our study accentuates the creation of optoelectronic microdevices for local phototherapy and functional imaging by using reflected light. Phototherapeutic micromodule consist of the light source, microprocessor and miniature optics with different kind of power supply: from autonomous with built-in batteries to remote supply by using pulsed magnetic field and supersmall coils. The developed prototype photomodule has size (phi) 8X16 mm and work duration with built-in battery and light diode up several hours at the average power from several tenths of mW to few mW. Preliminary clinical tests developed physiotherapeutic micrimodules in stomatology for treating the inflammation and in otolaryngology for treating tonsillitis and otitis are presented. The developed implanted electro- optical sources with typical size (phi) 4X0,8 mm and with remote supply were used for optical stimulation of photosensitive retina structure and electrostimulation of visual nerve. In this scheme the superminiature coil with 30 electrical integrated levels was used. Such devices were implanted in eyes of 175 patients with different vision problems during clinical trials in Institute of Eye's Surgery in Moscow. For functional imaging of skin layered structure LED arrays coupled photodiodes arrays were developed. The possibilities of this device for study drug diffusion and visualization small veins are discussed.

Development of the ion source for cluster implantation

NASA Astrophysics Data System (ADS)

Kulevoy, T. V.; Seleznev, D. N.; Kozlov, A. V.; Kuibeda, R. P.; Kropachev, G. N.; Alexeyenko, O. V.; Dugin, S. N.; Oks, E. M.; Gushenets, V. I.; Hershcovitch, A.; Jonson, B.; Poole, H. J.

2014-02-01

Bernas ion source development to meet needs of 100s of electron-volt ion implanters for shallow junction production is in progress in Institute for Theoretical and Experimental Physics. The ion sources provides high intensity ion beam of boron clusters under self-cleaning operation mode. The last progress with ion source operation is presented. The mechanism of self-cleaning procedure is described.

Carbon-fiber-reinforced PEEK fixation system in the treatment of spine tumors: a preliminary report.

PubMed

Boriani, Stefano; Tedesco, Giuseppe; Ming, Lu; Ghermandi, Riccardo; Amichetti, Maurizio; Fossati, Piero; Krengli, Marco; Mavilla, Loredana; Gasbarrini, Alessandro

2018-04-01

Protocols including combination of surgery and radiotherapy are more and more frequent in the treatment of bone tumors of the spine. In metastatic disease, combination of surgery and radiotherapy is since long time accepted, as based on clinical evidence. In primary tumors, combination of surgery and radiotherapy can be considered in all the cases in which a satisfactory oncological margin cannot be achieved: high-grade malignancies, recurrent tumors, huge tumors expanding in an extracompartimental area, and when tumor-free margin requires unacceptable functional sacrifices. However, metal implants are an obstacle in the collaboration between surgeons and radiation oncologists. Carbon-fiber-reinforced polyethil-ether-ether-ketone (CFR-PEEK) composite implants could make easier and more effective the treatment as radiolucent and not interfering with ionizing radiation and accelerated particles. The purpose of this article is to report the preliminary results from a cohort of patients treated with CFR-PEEK and to evaluate the safety and the non-inferiority of the device respect the commonly used titanium implants. This study concerns an ambispective cohort series of 34 tumor patients (14 metastases and 20 primaries, most of them recurrent) submitted to thoracic and lumbar spine fixation with a CFR-PEEK composite implants. Oncologic surgery was palliative decompression and fixation in 9 cases, tumor excision in 21, and enbloc resection in 4. Data collected for this preliminary report were all intraoperative remarks, incidence of complications, changes in neurological status, local control, and survival. All the cases were followed 6-36 months (mean 13 months). Only one intraoperative screw breakage occurred out of 232 implanted screws. Pain control and neurological improvement were the early clinical results. Two sacral screws loosening were found at 9 and 12 months in multilevel constructs performed on multirecurrent tumors. Six local recurrences were early found thanks to the implant radiolucency. Radiation oncologists' opinion was favourable as concerning better treatment planning on CT and lacking of scattering effect during the treatment. No artifacts on imaging studies mean early local recurrence detection. For radiation oncologists, no artifacts on imaging studies mean easier planning and no scattering effect means more effective and safe radiotherapy, particularly when particles are used. Moreover, it seems that the clinical use of CFR-PEEK composite implants may be safe and at least comparable with the commonly used titanium implants in terms of intraoperative complications, stability at weight bearing and at functional recovery. Larger patient series and longer follow-up are required to confirm these data.

Cavity evolution at grain boundaries as a function of radiation damage and thermal conditions in nanocrystalline nickel

DOE PAGES

Muntifering, Brittany; Blair, Sarah Jane; Gong, Cajer; ...

2015-12-30

Enhanced radiation tolerance of nanostructured metals is attributed to the high density of interfaces that can absorb radiation-induced defects. Here, cavity evolution mechanisms during cascade damage, helium implantation, and annealing of nanocrystalline nickel are characterized via in situ transmission electron microscopy (TEM). Films subjected to self-ion irradiation followed by helium implantation developed evenly distributed cavity structures, whereas films exposed in the reversed order developed cavities preferentially distributed along grain boundaries. Post-irradiation annealing and orientation mapping demonstrated uniform cavity growth in the nanocrystalline structure, and cavities spanning multiple grains. Furthermore, these mechanisms suggest limited ability to reduce swelling, despite the stabilitymore » of the nanostructure.« less

Microelectromechanical Systems (MEMS) Photoacoustic (PA) Detector of Terahertz (THz) Radiation for Chemical Sensing

DTIC Science & Technology

2014-03-01

26 Feb 2014 Ivan Medvedev, PhD (Member) Date iv AFIT-ENG-14-M-58 Abstract In this research effort, a Microelectromechanical...7. Separation by implantation of oxygen (SIMOX) is a process of creating silicon- on-insulator (SOI) wafers. Oxygen ions are implanted into a silicon...wafer. The depth of the insulating layer is dependent upon the power used during ion implantation [14]. .............................. 16  Figure 8

Implant outcomes poorer in patients with history of periodontal disease.

PubMed

Veitz-Keenan, Analia; Keenan, James R

2017-03-01

Data sourcesMedline and Embase databases and bibliographies of all included articles and relevant review articles were screened for possible inclusion.Study selectionLongitudinal studies were included reporting on implant survival, success, incidence of peri-implantitis, bone loss and periodontal status and on partially dentate patients with a history of treatment for periodontitis. There were no language restrictions for the included studies.Data extraction and synthesisAuthors independently and in duplicate assessed the studies for eligibility and data extraction. Disagreements were resolved by discussion and consensus. The methodological quality assessment of the included studies was done using an adapted Newcastle-Ottawa Scale (NOS). Confounding factors such as smoking, systemic disease influencing osseointegration, chemotherapy and radiation were assessed and adjusted in the analysis. Data were organised into tables and grouped in accordance with the study design.ResultsTwenty-four studies reported in 27 publications were included. Implant survival and success rate were higher in periodontally healthy patients.Twelve prospective cohort studies, five case series with a control group, four retrospective cohort studies and three studies with a sub group comparison were included.Bone loss and peri-implantitis were increased in patients with a history of treated periodontitis. More complications were reported in patients presenting with more severe forms of periodontitis. High heterogeneity among the studies in terms of study design, population, therapy, unit of analysis, inconsistent definitions of baseline and outcomes, inadequate reporting and confounding factors meant a meta-analysis could not be performed.Most of the studies showed better implant survival rates for the non-periodontitis group ranging from 91.67% to 100% compared to the treated periodontitis group 79.22% to 100% over a 1.2 to 16 year follow-up.ConclusionsImplants placed in patients treated for periodontal disease are associated with higher incidence of biological complications and lower success and survival rates than those placed in periodontally healthy patients. Severe forms of periodontal disease are associated with higher rates of implant loss. The conclusion of the review is limited by the strength of the evidence.

Bronchoscopic Implantation of a Novel Wireless Electromagnetic Transponder in the Canine Lung: A Feasibility Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayse, Martin L.; Parikh, Parag J.; Lechleiter, Kristen M.

2008-09-01

Purpose: The success of targeted radiation therapy for lung cancer treatment is limited by tumor motion during breathing. A real-time, objective, nonionizing, electromagnetic localization system using implanted electromagnetic transponders has been developed (Beacon electromagnetic transponder, Calypso Medical Technologies, Inc., Seattle, WA). We evaluated the feasibility and fixation of electromagnetic transponders bronchoscopically implanted in small airways of canine lungs and compared to results using gold markers. Methods and Materials: After approval of the Animal Studies Committee, five mongrel dogs were anesthetized, intubated, and ventilated. Three transponders were inserted into the tip of a plastic catheter, passed through the working channel ofmore » a flexible bronchoscope, and implanted into small airways of a single lobe using fluoroscopic guidance. This procedure was repeated for three spherical gold markers in the opposite lung. One, 7, 14, 28, and 60 days postimplantation imaging was used to assess implant fixation. Results: Successful bronchoscopic implantation was possible for 15 of 15 transponders and 12 of 15 gold markers; 3 markers were deposited in the pleural space. Fixation at 1 day was 15 of 15 for transponders and 12 of 12 for gold markers. Fixation at 60 days was 6 of 15 for transponders and 7 of 12 for gold markers, p value = 0.45. Conclusions: Bronchoscopic implantation of both transponders and gold markers into the canine lung is feasible, but fixation rates are low. If fixation rates can be improved, implantable electromagnetic transponders may allow improved radiation therapy for lung cancer by providing real-time continuous target tracking. Developmental work is under way to improve the fixation rates and to reduce sensitivity to implantation technique.« less

Implanted medical devices in the radiation environment of commercial spaceflight.

PubMed

Reyes, David P; McClure, Steven S; Chancellor, Jeffery C; Blue, Rebecca S; Castleberry, Tarah L; Vanderploeg, James M

2014-11-01

Some commercial spaceflight participants (SFPs) may have medical conditions that require implanted medical devices (IMDs), such as cardiac pacemakers, defibrillators, insulin pumps, or similar electronic devices. The effect of space radiation on the function of IMDs is unknown. This review will identify known effects of terrestrial and aviation electromagnetic interference (EMI) and radiation on IMDs in order to provide insight into the potential effects of radiation exposures in the space environment. A systematic literature review was conducted on available literature on human studies involving the effects of EMI as well as diagnostic and therapeutic radiation on IMDs. The literature review identified potential transient effects from EMI and diagnostic radiation levels as low as 10 mGy on IMDs. High-energy, therapeutic, ionizing radiation can cause more permanent device malfunctions at doses as low as 40 mGy. Radiation doses from suborbital flight altitudes and durations are anticipated to be less than those experienced during an average round-trip, cross-country airline flight and are unlikely to result in significant detriment, though longer, orbital flights may expose SFPs to doses potentially harmful to IMD function. Individuals with IMDs should experience few, if any, radiation-related device malfunctions during suborbital flight, but could have problems with radiation exposures associated with longer, orbital flights.

Effect of 935-MHz phone-simulating electromagnetic radiation on endometrial glandular cells during mouse embryo implantation.

PubMed

Liu, Wenhui; Zheng, Xinmin; Qu, Zaiqing; Zhang, Ming; Zhou, Chun; Ma, Ling; Zhang, Yuanzhen

2012-10-01

This study examined the impact of 935MHz phone-simulating electromagnetic radiation on embryo implantation of pregnant mice. Each 7-week-old Kunming (KM) female white mouse was set up with a KM male mouse in a single cage for mating overnight after induction of ovulation. In the first three days of pregnancy, the pregnant mice was exposed to electromagnetic radiation at low-intensity (150 μW/cm(2), ranging from 130 to 200 μW/cm(2), for 2- or 4-h exposure every day), mid-intensity (570 μW/cm(2), ranging from 400 to 700 μW/cm(2), for 2- or 4-h exposure every day) or high-intensity (1400 μW/cm(2), ranging from 1200 to 1500 μW/cm(2), for 2- or 4-h exposure every day), respectively. On the day 4 after gestation (known as the window of murine embryo implantation), the endometrium was collected and the suspension of endometrial glandular cells was made. Laser scanning microscopy was employed to detect the mitochondrial membrane potential and intracellular calcium ion concentration. In high-intensity, 2- and 4-h groups, mitochondrial membrane potential of endometrial glandular cells was significantly lower than that in the normal control group (P<0.05). The calcium ion concentration was increased in low-intensity 2-h group but decreased in high-intensity 4-h group as compared with the normal control group (P<0.05). However, no significant difference was found in mitochondrial membrane potential of endometrial glandular cells between low- or mid-intensity groups and the normal control group, indicating stronger intensity of the electromagnetic radiation and longer length of the radiation are required to inflict a remarkable functional and structural damage to mitochondrial membrane. Our data demonstrated that electromagnetic radiation with a 935-MHz phone for 4 h conspicuously decreased mitochondrial membrane potential and lowered the calcium ion concentration of endometrial glandular cells. It is suggested that high-intensity electromagnetic radiation is very likely to induce the death of embryonic cells and decrease the chance of their implantation, thereby posing a high risk to pregnancy.

Method of electroplating a conversion electron emitting source on implant

DOEpatents

Srivastava, Suresh C [Setauket, NY; Gonzales, Gilbert R [New York, NY; Adzic, Radoslav [East Setauket, NY; Meinken, George E [Middle Island, NY

2012-02-14

Methods for preparing an implant coated with a conversion electron emitting source (CEES) are disclosed. The typical method includes cleaning the surface of the implant; placing the implant in an activating solution comprising hydrochloric acid to activate the surface; reducing the surface by H.sub.2 evolution in H.sub.2SO.sub.4 solution; and placing the implant in an electroplating solution that includes ions of the CEES, HCl, H.sub.2SO.sub.4, and resorcinol, gelatin, or a combination thereof. Alternatively, before tin plating, a seed layer is formed on the surface. The electroplated CEES coating can be further protected and stabilized by annealing in a heated oven, by passivation, or by being covered with a protective film. The invention also relates to a holding device for holding an implant, wherein the device selectively prevents electrodeposition on the portions of the implant contacting the device.

Polyurethane Implants in 2-Stage Breast Reconstruction: 9-Year Clinical Experience.

PubMed

Pompei, Stefano; Arelli, Floriana; Labardi, Lara; Marcasciano, Fabio; Evangelidou, Dora; Ferrante, Gianluigi

2017-02-01

Capsular contracture (CC) is a major complication of breast surgery with smooth and textured implants. Polyurethane (PU) foam-coated breast implants were developed to decrease the incidence of CC. The authors determined the incidence of CC following 2-stage breast reconstruction using PU foam-covered implants, with and without radiation therapy. The records of 92 patients who received 115 PU implants were retrospectively reviewed. The rates of CC over time were compared for irradiated and nonirradiated groups with a Kaplan-Meier analysis and log-rank test. CC rates also were analyzed with respect to age. The median follow-up time for patients was 103.3 months. Nine patients experienced unilateral Baker grade III or IV fibrous CC, including 6 patients from the irradiated group and 3 patients from the nonirradiated group. The overall cumulative incidence of CC at 9 years was 8.1%. In the irradiated and nonirradiated groups, the 9-year cumulative incidence was 10.7% and 5.5%, respectively. CC occurred within 3 years in the irradiated group and within 7 years in the nonirradiated group. The incidence of CC appeared to be higher among younger patients. Radiation therapy increases the risk of high-grade CC with textured or smooth implants. PU implants are associated with a much lower cumulative incidence of CC following 2-stage breast reconstruction, even when radiotherapy is performed. LEVEL OF EVIDENCE 3. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

An experimental palladium-103 seed (OptiSeedexp) in a biocompatible polymer without a gold marker: characterization of dosimetric parameters including the interseed effect.

PubMed

Abboud, F; Scalliet, P; Vynckier, S

2008-12-01

Permanent implantation of 125I (iodine) or 103Pd (palladium) sources is a popular treatment option in the management of early stage prostate cancer. New sources are being developed, some of which are being marketed for different clinical applications. A new technique of adjuvant stereotactic permanent seed breast implant, similar to that used in the treatment of prostate cancer, has been proposed by [N. Jansen et al., Int. J. Radiat. Oncol. Biol. Phys. 67, 1052-1058 (2007)] with encouraging results. The presence of artifacts from the metallic seeds, however, can disturb follow-up imaging. The development of plastic seeds has reduced these artifacts. This paper presents a feasibility study of the advantages of palladium-103 seeds, encapsulated with a biocompatible polymer, for future clinical applications, and on the effect of the gold marker on the dosimetric characteristics of such seeds. Experimental palladium seeds, OptiSeedexp, were manufactured by International Brachytherapy (IBt), Seneffe, Belgium, from a biocompatible polymer, including the marker. Apart from the absence of a gold marker, the studied seed has an identical design to the OptiSeed103 [Phys. Med. Biol. 50, 1493-1504 (2005)]; [Appl. Radiat. Isot. 63, 311-321 (2005)]. Polymer encapsulation was preferred by IBt in order to reduce the quantity of radioactive material needed for a given dose rate and to reduce the anisotropy of the radiation field around the seed. In addition, this design is intended to decrease the interseed effects that can occur as a result of the marker and the encapsulation. Dosimetric measurements were performed using LiF thermoluminescent dosimeters (1 mm3) in solid water phantoms (WT1). Measured data were compared to Monte Carlo simulated data in solid water using the MCNP code, version 4C. Updated cross sections [Med. Phys. 30, 701-711 (2003)] were used. As the measured and calculated data were in agreement, Monte Carlo calculations were then performed in liquid water to obtain relevant dosimetric data as required by TG-43U1 recommendations. Comparison of the results with previous studies of OptiSeed103 [Phys. Med. Biol. 50, 1493-1504 (2005)]; [Appl. Radiat. Isot. 63, 311-321 (2005)], and of InterSource103 [Appl. Radiat. Isot. 57, 805-811 (2002)] showed very good agreement for the dose rate constant and for the radial dose function. With respect to the anisotropy function, the relative dose (anisotropy value relative to 90 degrees) from the polymer seed at a distance of 3 cm was close to unity (105%) at 0 degrees, whereas the relative values for the OptiSeed103 with a gold marker and the titanium-encapsulated InterSource103 seed decreased to 70% and 40%, respectively. The interseed effect from one seed was negligible and in the order of calculation uncertainty, making calculation of the dose rate distribution of the studied seeds, according to TG43U1 recommendations, more accurate and closer to reality. This feasibility study shows that due to the low energy of palladium-103, the negligible interseed effect and the reduced artifacts in postimplant medical imaging, this experimental plastic seed would be a good source for breast brachytherapy. This feasibility study was carried out in collaboration with IBt and will be continued with a study of its visibility in different tissues.

An experimental palladium-103 seed (OptiSeed{sup exp}) in a biocompatible polymer without a gold marker: Characterization of dosimetric parameters including the interseed effect

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abboud, F.; Scalliet, P.; Vynckier, S.

Permanent implantation of {sup 125}I (iodine) or {sup 103}Pd (palladium) sources is a popular treatment option in the management of early stage prostate cancer. New sources are being developed, some of which are being marketed for different clinical applications. A new technique of adjuvant stereotactic permanent seed breast implant, similar to that used in the treatment of prostate cancer, has been proposed by [N. Jansen et al., Int. J. Radiat. Oncol. Biol. Phys. 67, 1052-1058 (2007)] with encouraging results. The presence of artifacts from the metallic seeds, however, can disturb follow-up imaging. The development of plastic seeds has reduced thesemore » artifacts. This paper presents a feasibility study of the advantages of palladium-103 seeds, encapsulated with a biocompatible polymer, for future clinical applications, and on the effect of the gold marker on the dosimetric characteristics of such seeds. Experimental palladium seeds, OptiSeed{sup exp}, were manufactured by International Brachytherapy (IBt), Seneffe, Belgium, from a biocompatible polymer, including the marker. Apart from the absence of a gold marker, the studied seed has an identical design to the OptiSeed{sup 103}[Phys. Med. Biol. 50, 1493-1504 (2005)]; [Appl. Radiat. Isot. 63, 311-321 (2005)]. Polymer encapsulation was preferred by IBt in order to reduce the quantity of radioactive material needed for a given dose rate and to reduce the anisotropy of the radiation field around the seed. In addition, this design is intended to decrease the interseed effects that can occur as a result of the marker and the encapsulation. Dosimetric measurements were performed using LiF thermoluminescent dosimeters (1 mm{sup 3}) in solid water phantoms (WT1). Measured data were compared to Monte Carlo simulated data in solid water using the MCNP code, version 4C. Updated cross sections [Med. Phys. 30, 701-711 (2003)] were used. As the measured and calculated data were in agreement, Monte Carlo calculations were then performed in liquid water to obtain relevant dosimetric data as required by TG-43U1 recommendations. Comparison of the results with previous studies of OptiSeed{sup 103}[Phys. Med. Biol. 50, 1493-1504 (2005)]; [Appl. Radiat. Isot. 63, 311-321 (2005)], and of InterSource{sup 103}[Appl. Radiat. Isot. 57, 805-811 (2002)] showed very good agreement for the dose rate constant and for the radial dose function. With respect to the anisotropy function, the relative dose (anisotropy value relative to 90 degree sign ) from the polymer seed at a distance of 3 cm was close to unity (105%) at 0 degree sign , whereas the relative values for the OptiSeed{sup 103} with a gold marker and the titanium-encapsulated InterSource{sup 103} seed decreased to 70% and 40%, respectively. The interseed effect from one seed was negligible and in the order of calculation uncertainty, making calculation of the dose rate distribution of the studied seeds, according to TG43U1 recommendations, more accurate and closer to reality. This feasibility study shows that due to the low energy of palladium-103, the negligible interseed effect and the reduced artifacts in postimplant medical imaging, this experimental plastic seed would be a good source for breast brachytherapy. This feasibility study was carried out in collaboration with IBt and will be continued with a study of its visibility in different tissues.« less

Systematic study of target localization for bioluminescence tomography guided radiation therapy

PubMed Central

Yu, Jingjing; Zhang, Bin; Iordachita, Iulian I.; Reyes, Juvenal; Lu, Zhihao; Brock, Malcolm V.; Patterson, Michael S.; Wong, John W.

2016-01-01

Purpose: To overcome the limitation of CT/cone-beam CT (CBCT) in guiding radiation for soft tissue targets, the authors developed a spectrally resolved bioluminescence tomography (BLT) system for the small animal radiation research platform. The authors systematically assessed the performance of the BLT system in terms of target localization and the ability to resolve two neighboring sources in simulations, tissue-mimicking phantom, and in vivo environments. Methods: Multispectral measurements acquired in a single projection were used for the BLT reconstruction. The incomplete variables truncated conjugate gradient algorithm with an iterative permissible region shrinking strategy was employed as the optimization scheme to reconstruct source distributions. Simulation studies were conducted for single spherical sources with sizes from 0.5 to 3 mm radius at depth of 3–12 mm. The same configuration was also applied for the double source simulation with source separations varying from 3 to 9 mm. Experiments were performed in a standalone BLT/CBCT system. Two self-illuminated sources with 3 and 4.7 mm separations placed inside a tissue-mimicking phantom were chosen as the test cases. Live mice implanted with single-source at 6 and 9 mm depth, two sources at 3 and 5 mm separation at depth of 5 mm, or three sources in the abdomen were also used to illustrate the localization capability of the BLT system for multiple targets in vivo. Results: For simulation study, approximate 1 mm accuracy can be achieved at localizing center of mass (CoM) for single-source and grouped CoM for double source cases. For the case of 1.5 mm radius source, a common tumor size used in preclinical study, their simulation shows that for all the source separations considered, except for the 3 mm separation at 9 and 12 mm depth, the two neighboring sources can be resolved at depths from 3 to 12 mm. Phantom experiments illustrated that 2D bioluminescence imaging failed to distinguish two sources, but BLT can provide 3D source localization with approximately 1 mm accuracy. The in vivo results are encouraging that 1 and 1.7 mm accuracy can be attained for the single-source case at 6 and 9 mm depth, respectively. For the 2 sources in vivo study, both sources can be distinguished at 3 and 5 mm separations, and approximately 1 mm localization accuracy can also be achieved. Conclusions: This study demonstrated that their multispectral BLT/CBCT system could be potentially applied to localize and resolve multiple sources at wide range of source sizes, depths, and separations. The average accuracy of localizing CoM for single-source and grouped CoM for double sources is approximately 1 mm except deep-seated target. The information provided in this study can be instructive to devise treatment margins for BLT-guided irradiation. These results also suggest that the 3D BLT system could guide radiation for the situation with multiple targets, such as metastatic tumor models. PMID:27147371

Radiation damage and defect behavior in ion-implanted, lithium counterdoped silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Mehta, S.; Swartz, C. K.

1984-01-01

Boron doped silicon n+p solar cells were counterdoped with lithium by ion implantation and the resuitant n+p cells irradiated by 1 MeV electrons. The function of fluence and a Deep Level Transient Spectroscopy (DLTS) was studied to correlate defect behavior with cell performance. It was found that the lithium counterdoped cells exhibited significantly increased radiation resistance when compared to boron doped control cells. It is concluded that the annealing behavior is controlled by dissociation and recombination of defects. The DLTS studies show that counterdoping with lithium eliminates at least three deep level defects and results in three new defects. It is speculated that the increased radiation resistance of the counterdoped cells is due primarily to the interaction of lithium with oxygen, single vacanies and divacancies and that the lithium-oxygen interaction is the most effective in contributing to the increased radiation resistance.

Monte Carlo calculated doses to treatment volumes and organs at risk for permanent implant lung brachytherapy

NASA Astrophysics Data System (ADS)

Sutherland, J. G. H.; Furutani, K. M.; Thomson, R. M.

2013-10-01

Iodine-125 (125I) and Caesium-131 (131Cs) brachytherapy have been used with sublobar resection to treat stage I non-small cell lung cancer and other radionuclides, 169Yb and 103Pd, are considered for these treatments. This work investigates the dosimetry of permanent implant lung brachytherapy for a range of source energies and various implant sites in the lung. Monte Carlo calculated doses are calculated in a patient CT-derived computational phantom using the EGsnrc user-code BrachyDose. Calculations are performed for 103Pd, 125I, 131Cs seeds and 50 and 100 keV point sources for 17 implant positions. Doses to treatment volumes, ipsilateral lung, aorta, and heart are determined and compared to those determined using the TG-43 approach. Considerable variation with source energy and differences between model-based and TG-43 doses are found for both treatment volumes and organs. Doses to the heart and aorta generally increase with increasing source energy. TG-43 underestimates the dose to the heart and aorta for all implants except those nearest to these organs where the dose is overestimated. Results suggest that model-based dose calculations are crucial for selecting prescription doses, comparing clinical endpoints, and studying radiobiological effects for permanent implant lung brachytherapy.

Influence of irradiation on the osteoinductive potential of demineralized bone matrix.

PubMed

Wientroub, S; Reddi, A H

1988-04-01

Samples of demineralized bone matrix (DBM) were exposed to graduated doses of radiation (1-15 Megarad) (Mrad) utilizing a linear accelerator and then implanted into the thoracic region of Long-Evans rats. Subcutaneous implantation of DBM into allogenic rats induces endochondral bone. In response to matrix implantation, a cascade of events ensues; mesenchymal cell proliferation on day 3 postimplantation, chondrogenesis on day 7, calcification of the cartilagenous matrix and chondrolysis on day 9, and osteogenesis on day 11 resulting in formation of an ossicle containing active hemopoietic tissue. Bone formation was assessed by measuring alkaline phosphatase activity, the rate of mineralization was determined by measuring 45Ca incorporation to bone mineral, and 40Ca content measured the extent of mineralization; acid phosphatase activity was used as a parameter for bone resorption. The dose of radiation (2.5 Mrad) currently used by bone banks for sterilization of bone tissue did not destroy the bone induction properties of DBM. Furthermore, radiation of 3-5 Mrad even enhanced bone induction, insofar as it produced more bone at the same interval of time than was obtained from unirradiated control samples. None of the radiation doses used in these experiments abolished bone induction, although the response induced by matrix irradiated with doses higher than 5 Mrad was delayed.

The prospect of carbon fiber implants in radiotherapy

PubMed Central

Xiao‐bin, Tang; Chang‐ran, Geng; Da, Chen

2012-01-01

Because of their superior characteristics, carbonaceous materials, which are still at their early stage of development, have garnered significant interest. Because of their low atomic number, carbonaceous orthopedic implants possess radiation properties similar to biological tissues and, therefore, they are more suitable to patients in need of radiotherapy. The effects of stainless steel, titanium, and carbon plates on radiation dose distributions were investigated in this work using Monte Carlo simulations and TLD measurements for 6 MV photon beams. It is found that carbon plates will neither increase the incident surface dose, nor lead to the decrease of exit surface dose (the effect of a second build‐up). Carbon fiber orthopedic implants have a good prospect for radiotherapy patients because they have minimal perturbation effects on the radiotherapy dose distribution. PACS number: 87.55.K‐,87.55.Gh, 87.55.ne PMID:22766953

Analysis of dose to patient, spouse/caretaker, and staff, from an implanted trackable radioactive fiducial for use in the radiation treatment of prostate cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neustadter, David; Barnea, Gideon; Stokar, Saul

Purpose: A fiducial tracking system based on a novel radioactive tracking technology is being developed for real-time target tracking in radiation therapy. In this study, the authors calculate the radiation dose to the patient, the spouse/caretaker, and the medical staff that would result from a 100 {mu}Ci Ir192 radioactive fiducial marker permanently implanted in the prostate of a radiation therapy patient. Methods: Local tissue dose was calculated by Monte Carlo simulation. The patient's whole body effective dose equivalent was calculated by summing the doses to the sensitive organs. Exposure of the spouse/caretaker was calculated from the NRC guidelines. Exposure ofmore » the medical staff was based on estimates of proximity to and time spent with the patient. Results: The local dose is below 40 Gy at 5 mm from the marker and below 10 Gy at 10 mm from the marker. The whole body effective dose equivalent to the patient is 64 mSv. The dose to the spouse/caretaker is 0.25 mSv. The annual exposures of the medical staff are 0.2 mSv for a doctor performing implantations and 0.34 mSv for a radiation therapist positioning patients for therapy. Conclusions: The local dose is not expected to have any clinically significant effect on the surrounding tissue which is irradiated during therapy. The dose to the patient is small in comparison to the whole body dose received from the therapy itself. The exposure of all other people is well below the recommended limits. The authors conclude that there is no radiation exposure related contraindication for use of this technology in the radiation treatment of prostate cancer.« less

Virtual Humans for Implantable Device Safety Assessment in MRI: Mitigating Magnetic Resonance Imaging Hazards for Implanted Medical Devices.

PubMed

Brown, James E; Qiang, Rui; Stadnik, Paul J; Stotts, Larry J; Von Arx, Jeffrey A

2017-01-01

Magnetic resonance imaging (MRI) is the preferred modality for soft tissue imaging because of its nonionizing radiation and lack of contrast agent. Due to interactions between the MR system and active implantable medical devices (AIMDs), patients with implants such as pacemakers are generally denied access to MRI, which presents a detriment to that population. It has been estimated that 50-75% of patients with a cardiac device were denied access to MRI scanning and, moreover, that 17% of pacemaker patients need an MRI within 12 months of implantation [1]. In recent years, AIMD manufacturers, such as Biotronik, have assessed the conditional safety of devices in MRI.

Representative marketing-oriented study on implants in the Austrian population. I. Level of information, sources of information and need for patient information.

PubMed

Tepper, Gabor; Haas, Robert; Mailath, Georg; Teller, Christoph; Zechner, Werner; Watzak, Georg; Watzek, Georg

2003-10-01

The number of dental implants inserted annually worldwide has been estimated to come close to a million. But the level of information available to patients about realistic, evidence-based treatment options by implants is often enough more than fragmentary, and what is disseminated by the media and the industry does not always reflect evidence-based empirical data. This survey of 1000 adults presented with 18 questions was designed to shed light on several points. These were (1). level of subjective patient information, (2). sources of information and prejudices, (3). future demand for implant treatment and target groups for patient information campaigns, and (4). potential misinformation, information deficits, discrepancies of information and how these come about. Of those questioned, 20% said unprompted that implants were a possibility to replace missing teeth. When prompted, 72% said that they knew about dental implants. Most of those questioned felt poorly informed about the options for replacing missing teeth and many knew less about implants than about other alternatives. The dentist was said to be the desired source of information, but 77% of those questioned reported that their dentists did not practice implant dentistry. More than 79% of those questioned did not know whether their dentist worked with implants. Forty-four percent thought that implants should only be placed by specially trained doctors. Sixty-one percent were of the opinion that dentists who provide implant dentistry were better qualified than their nonimplanting colleagues. Half of those questioned attributed implant failures to allergies and incompatibilities, the other half to poor medical care. Only 29% incriminated poor oral hygiene as a cause of implant failure. Future strategies should be geared to more professional public relations and patient information. Internationally operating qualified implant institutions could contribute much to balance discrepant information.

Implantation of a HeartMate II left ventricular assist device via left thoracotomy.

PubMed

Cho, Yang Hyun; Deo, Salil V; Schirger, John A; Pereira, Naveen L; Stulak, John M; Park, Soon J

2012-11-01

Left thoracotomy was used as an approach for the implantation of pulsatile ventricular assist devices. Avoiding the standard approach of median sternotomy is attractive in patients undergoing complicated redo cardiac surgery, especially with prior mediastinal radiation. We report a case of the use of left thoracotomy for the implantation of the HeartMate II axial-flow pump. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Influence of thermal annealing and radiation enhanced diffusion processes on surface plasmon resonance of gold implanted dielectric matrices

NASA Astrophysics Data System (ADS)

Devi, Ksh. Devarani; Ojha, Sunil; Singh, Fouran

2018-03-01

Gold nanoparticles (AuNPs) embedded in fused silica and sapphire dielectric matrices were synthesized by Au ion implantation. Systematic investigations were carried out to study the influence of implantation dose, post annealing temperature, swift heavy ion (SHI) irradiation and radiation enhanced diffusion (RED). Rutherford Backscattering Spectrometry (RBS) measurements were carried out to quantify concentration and depth profile of Au present in the host matrices. X-ray diffraction (XRD) was employed to characterize AuNPs formation. As-implanted and post-annealed films were irradiated using 100 MeV Ag ions to investigate the effect of electronic energy deposition on size and shape of NPs, which is estimated indirectly by the peak shape analysis of surface plasmon resonance (SPR). The effect of volume fraction of Au and their redistribution is also reported. A strong absorption in near infra red region is also noticed and understood by the formation of percolated NPs in dielectric matrices. It is quite clear from these results that the effect of RED assisted Oswald ripening is much more pronounced than the conventional Oswald ripening for the growth of NPs in the case of silica host matrices. However for sapphire matrices, it seems that growth of NPs already completed during implantation and it may be attributed to the high diffusivity of Au in sapphire matrices during implantation process.

A novel imaging approach for prostate cancer is tested in new clinical trial | Center for Cancer Research

Cancer.gov

Prostate cancer patients who have failed standard radiation therapy have the options of surgery, radioactive seed implantation or cryoablation. Deborah Citrin, M.D., of the Radiation Oncology Branch is leading a study of stereotactic body radiation therapy (SBRT) to treat prostate cancer that has recurred locally after standard radiation therapy. The goal of this study is to

Implantable Heart Aid

NASA Technical Reports Server (NTRS)

1984-01-01

CPI's human-implantable automatic implantable defibrillator (AID) is a heart assist system, derived from NASA's space circuitry technology, that can prevent erratic heart action known as arrhythmias. Implanted AID, consisting of microcomputer power source and two electrodes for sensing heart activity, recognizes onset of ventricular fibrillation (VF) and delivers corrective electrical countershock to restore rhythmic heartbeat.

Retreatment of recurrent carcinoma of the head and neck by afterloading interstitial 192Ir implant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emami, B.; Marks, J.E.

From January 1975 to December 1980, 25 patients with persistent or recurrent carcinomas of the head and neck were retreated for palliation at the Division of Radiation Oncology, Mallinckrodt Institute of Radiology. These patients had all undergone extensive previous treatment by surgery and/or radiation. All were retreated with 192Ir interstitial implant with or without external radiation and/or surgical excision. Of 25 patients, 13 had complete response (CR) and 6 had partial response for a follow-up period of 1 to 7 years. Of 13 patients with CR, 6 are alive with no evidence of disease (NED) and two died NED. Detailedmore » results are presented and the new strategy for such patients is discussed.« less

[Role of the technician in a brachytherapy department].

PubMed

Bélot-Cheval, V; Lemoine, L; Cuisinier, C; Gensse, M-C; Lasbareilles, O

2013-04-01

The role of the technician in a brachytherapy department is essential for the cohesion of the treatment team made up of the radiation oncologist, the physicist, and the technician. He/she collaborates in the different treatment steps such as taking care of the patients, training of the professionals and research studies in collaboration with the team. He participates in all steps of the treatment such as preparation, technician's consultation, catheters/templates and radioactives sources implant, dose distribution analysis and treatment. He looks after the management of planning, radioactive sources and chemist's equipments. He takes part in the training of the junior technician, and support doctors and physicists in different studies. The procedure writing and the presentation of professional practices are also part of the technician task. Copyright © 2013 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

The effect of metallic implants on radiation therapy in spinal tumor patients with metallic spinal implants.

PubMed

Son, Seok Hyun; Kang, Young Nam; Ryu, Mi-Ryeong

2012-01-01

The aim of this study was to evaluate the effect of metallic implants on the dose calculation for radiation therapy in patients with metallic implants and to find a way to reduce the error of dose calculation. We made a phantom in which titanium implants were inserted into positions similar to the implant positions in spinal posterior/posterolateral fusion. We compared the calculated dose of the treatment planning systems with the measured dose in the treatment equipment. We used 3 kinds of computed tomography (CT) (kilovoltage CT, extended-scaled kilovoltage CT, and megavoltage CT) and 3 kinds of treatment equipment (ARTISTE, TomoTherapy Hi-Art, and Cyberknife). For measurement of doses, we used an ionization chamber and Gafchromic external beam therapy film. The absolute doses that were measured using an ionization chamber at the isocenter in the titanium phantom were on average 1.9% lower than those in the reference phantom (p = 0.002). There was no statistically significant difference according to the kinds of CT images, the treatment equipment, and the size of the targets. As the distance from the surface of the titanium implants became closer, the measured doses tended to decrease (p < 0.001), and this showed a statistically significant difference among the kinds of CT images: the effect of metallic implants was less in the megavoltage CT than in the kilovoltage CT or the extended-scaled kilovoltage CT. The error caused by the titanium implants was beyond a clinically acceptable range. To reduce the error of dose calculation, we suggest that the megavoltage CT be used for planning. In addition, it is necessary to consider the distance between the titanium implants and the targets or the organs at risk to prescribe the dose for the target and the dose constraint for the organs at risk. Copyright © 2012 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

The effect of metallic implants on radiation therapy in spinal tumor patients with metallic spinal implants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Son, Seok Hyun; Kang, Young Nam; Ryu, Mi-Ryeong, E-mail: mrryu@catholic.ac.kr

2012-04-01

The aim of this study was to evaluate the effect of metallic implants on the dose calculation for radiation therapy in patients with metallic implants and to find a way to reduce the error of dose calculation. We made a phantom in which titanium implants were inserted into positions similar to the implant positions in spinal posterior/posterolateral fusion. We compared the calculated dose of the treatment planning systems with the measured dose in the treatment equipment. We used 3 kinds of computed tomography (CT) (kilovoltage CT, extended-scaled kilovoltage CT, and megavoltage CT) and 3 kinds of treatment equipment (ARTISTE, TomoTherapymore » Hi-Art, and Cyberknife). For measurement of doses, we used an ionization chamber and Gafchromic external beam therapy film. The absolute doses that were measured using an ionization chamber at the isocenter in the titanium phantom were on average 1.9% lower than those in the reference phantom (p = 0.002). There was no statistically significant difference according to the kinds of CT images, the treatment equipment, and the size of the targets. As the distance from the surface of the titanium implants became closer, the measured doses tended to decrease (p < 0.001), and this showed a statistically significant difference among the kinds of CT images: the effect of metallic implants was less in the megavoltage CT than in the kilovoltage CT or the extended-scaled kilovoltage CT. The error caused by the titanium implants was beyond a clinically acceptable range. To reduce the error of dose calculation, we suggest that the megavoltage CT be used for planning. In addition, it is necessary to consider the distance between the titanium implants and the targets or the organs at risk to prescribe the dose for the target and the dose constraint for the organs at risk.« less

Optimization in Radiation Therapy: Applications in Brachytherapy and Intensity Modulated Radiation Therapy

NASA Astrophysics Data System (ADS)

McGeachy, Philip David

Over 50% of cancer patients require radiation therapy (RT). RT is an optimization problem requiring maximization of the radiation damage to the tumor while minimizing the harm to the healthy tissues. This dissertation focuses on two main RT optimization problems: 1) brachytherapy and 2) intensity modulated radiation therapy (IMRT). The brachytherapy research involved solving a non-convex optimization problem by creating an open-source genetic algorithm optimizer to determine the optimal radioactive seed distribution for a given set of patient volumes and constraints, both dosimetric- and implant-based. The optimizer was tested for a set of 45 prostate brachytherapy patients. While all solutions met the clinical standards, they also benchmarked favorably with those generated by a standard commercial solver. Compared to its compatriot, the salient features of the generated solutions were: slightly reduced prostate coverage, lower dose to the urethra and rectum, and a smaller number of needles required for an implant. Historically, IMRT requires modulation of fluence while keeping the photon beam energy fixed. The IMRT-related investigation in this thesis aimed at broadening the solution space by varying photon energy. The problem therefore involved simultaneous optimization of photon beamlet energy and fluence, denoted by XMRT. Formulating the problem as convex, linear programming was applied to obtain solutions for optimal energy-dependent fluences, while achieving all clinical objectives and constraints imposed. Dosimetric advantages of XMRT over single-energy IMRT in the improved sparing of organs at risk (OARs) was demonstrated in simplified phantom studies. The XMRT algorithm was improved to include clinical dose-volume constraints and clinical studies for prostate and head and neck cancer patients were investigated. Compared to IMRT, XMRT provided improved dosimetric benefit in the prostate case, particularly within intermediate- to low-dose regions (≤ 40 Gy) for OARs. For head and neck cases, XMRT solutions showed no significant disadvantage or advantage over IMRT. The deliverability concerns for the fluence maps generated from XMRT were addressed by incorporating smoothing constraints during the optimization and through successful generation of treatment machine files. Further research is needed to explore the full potential of the XMRT approach to RT.

In vitro synchrotron-based radiography of micro-gap formation at the implant-abutment interface of two-piece dental implants.

PubMed

Rack, A; Rack, T; Stiller, M; Riesemeier, H; Zabler, S; Nelson, K

2010-03-01

Micro-gap formation at the implant-abutment interface of two-piece dental implants was investigated in vitro using high-resolution radiography in combination with hard X-ray synchrotron radiation. Images were taken with the specimen under different mechanical loads of up to 100 N. The aim of this investigation was to prove the existence of micro-gaps for implants with conical connections as well as to study the mechanical behavior of the mating zone of conical implants during loading. Synchrotron-based radiography in comparison with classical laboratory radiography yields high spatial resolution in combination with high contrast even when exploiting micro-sized features in highly attenuating objects. The first illustration of a micro-gap which was previously indistinguishable by laboratory methods underlines that the complex micro-mechanical behavior of implants requires further in vitro investigations where synchrotron-based micro-imaging is one of the prerequisites.

Dedicated high dose rate 192Ir brachytherapy radiation fields for in vitro cell exposures at variable source-target cell distances: killing of mammalian cells depends on temporal dose rate fluctuation

NASA Astrophysics Data System (ADS)

Veigel, Cornelia; Hartmann, Günther H.; Fritz, Peter; Debus, Jürgen; Weber, Klaus-Josef

2017-02-01

Afterloading brachytherapy is conducted by the stepwise movement of a radioactive source through surgically implanted applicator tubes where at predefined dwell positions calculated dwell times optimize spatial dose delivery with respect to a planned dose level. The temporal exposure pattern exhibits drastic fluctuations in dose rate at a given coordinate and within a single treatment session because of the discontinuous and repeated source movement into the target volume. This could potentially affect biological response. Therefore, mammalian cells were exposed as monolayers to a high dose rate 192Ir source by utilizing a dedicated irradiation device where the distance between a planar array of radioactive source positions and the plane of the cell monolayer could be varied from 2.5 mm to 40 mm, thus varying dose rate pattern for any chosen total dose. The Gammamed IIi afterloading system equipped with a nominal 370 GBq (10 Ci) 192-Ir source was used to irradiate V79 Chinese hamster lung fibroblasts from both confluent and from exponential growth phase with dose up to 12 Gy (at room temperature, total exposure not exceeding 1 h). For comparison, V79 cells were also exposed to 6 MV x-rays from a clinical linear accelerator (dose rate of 2.5 Gy min-1). As biological endpoint, cell survival was determined by standard colony forming assay. Dose measurements were conducted with a diamond detector (sensitive area 7.3 mm2), calibrated by means of 60Co radiation. Additionally, dose delivery was simulated by Monte Carlo calculations using the EGSnrc code system. The calculated secondary electron fluence spectra at the cell location did not indicate a significant change of radiation quality (i.e. higher linear energy transfer) at the lower distances. Clonogenic cell survival curves obtained after brachytherapy exhibited an altered biological response compared to x-rays which was characterized by a significant reduction of the survival curve shoulder when dose rate fluctuations were high. Therefore, also for the time scale of the present investigation, cellular effects of radiation are not invariant to the temporal pattern in dose rate. We propose that with high dose rate variation the cells activate less efficiently their DNA damage response than after continuous irradiation.

Evolution of power sources for implantable cardioverter defibrillators

NASA Astrophysics Data System (ADS)

Crespi, Ann M.; Somdahl, Sonja K.; Schmidt, Craig L.; Skarstad, Paul M.

The evolution of seven generations of power sources for implantable cardioverter defibrillators (ICD) is presented. The packaging efficiency of the power sources has steadily increased, resulting in smaller, lighter batteries while maintaining the required electrical characteristics. The main areas for improvement were reduction of headspace volume, reduction of separator volume, and a change from a two-cell battery to a single cell.

Synthesis of lithium nitride for neutron production target of BNCT by in situ lithium deposition and ion implantation

NASA Astrophysics Data System (ADS)

Ishiyama, S.; Baba, Y.; Fujii, R.; Nakamura, M.; Imahori, Y.

2012-12-01

To achieve high performance of BNCT (Boron Neutron Capture Therapy) device, Li3N/Li/Pd/Cu four layered Li target was designed and the structures of the synthesized four layered target were characterized by X-ray photoelectron spectroscopy. For the purpose of avoiding the radiation blistering and lithium evaporation, in situ vacuum deposition and nitridation techniques were established for in situ production and repairing maintenance of the lithium target. Following conclusions were derived: Uniform lithium layer of a few hundreds nanometer was formed on Pd/Cu multilayer surface by in situ vacuum deposition technique using metallic lithium as a source material. Lithium nitrides were formed by in situ nitridation reaction by the implantation of low-energy nitrogen ions on the deposited lithium layer surface. The chemical states of the nitridated zone were close to the stoichiometric lithium nitride, Li3N. This nitridated zone formed on surface of four layered lithium target is stable for a long time in air condition. The in situ nitridation is effective to protect lithium target from degradation by unfavorable reactions.

SU-F-T-314: Estimation of Dose Distributions with Different Types of Breast Implants in Various Radiation Treatment Techniques for Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, M; Lee, S; Suh, T

Purpose: This study investigates the effects of different kinds and designs of commercialized breast implants on the dose distributions in breast cancer radiotherapy under a variety of conditions. Methods: The dose for the clinical conventional tangential irradiation, Intensity Modulated Radiation Therapy (IMRT), volumetric modulated arc therapy (VMAT) breast plans was measured using radiochromic films and stimulated luminescence dosimeter (OSLD). The radiochromic film was used as an integrating dosimeter, while the OSLDs were used for real-time dosimetry to isolate the contribution of dose from individual segment. The films were placed at various slices in the Rando phantom and between the bodymore » and breast surface OSLDs were used to measure skin dose at 18 positions spaced on the two (right/left) breast. The implant breast was placed on the left side and the phantom breast was remained on the right side. Each treatment technique was performed on different size of the breasts and different shape of the breast implant. The PTV dose was prescribed 50.4 Gy and V47.88≥95%. Results: In different shapes of the breast implant, because of the shadow formed extensive around the breast implant, dose variation was relatively higher that of prescribed dose. As the PTV was delineated on the whole breast, maximum 5% dose error and average 3% difference was observed averagely. VMAT techniques largely decrease the contiguous hot spot in the skin by an average of 25% compared with IMRT. The both IMRT and VMAT techniques resulted in lower doses to normal critical structures than tangential plans for nearly all dose analyzation. Conclusion: Compared to the other technique, IMRT reduced radiation dose exposure to normal tissues and maintained reasonable target homogeneity and for the same target coverage, VMAT can reduce the skin dose in all the regions of the body.« less

Temperature sensor based on a polymer diffraction grating with silver nanoparticles

NASA Astrophysics Data System (ADS)

Nuzhdin, V. I.; Valeev, V. F.; Galyautdinov, M. F.; Osin, Yu. N.; Stepanov, A. L.

2018-01-01

The method is suggested for producing an optical temperature noncontact sensor on a polymer polymethylmethacrylate (PMMA) substrate with a diffraction optical element formed by implanting low-energy high-dose silver ions through a surface mask. Ion implantation is performed at an energy of 30 keV, a radiation dose of 5.0 × 1016 ion cm-2 and an ion beam current density of 2 μA cm-2 through a surface metal mask having the form of grid with square periodical holes (cells) of size 25 μm. In the course of implantation, silver nanoparticles are produced in periodical unmasked domains of irradiated PMMA. Operation of the temperature sensor on diffraction microstructures made of polymer with silver nanoparticles is demonstrated in the range from 20 °C to 95 °C by testing it with a probe radiation of a He - Ne laser.

Viability of dental implants in head and neck irradiated patients: A systematic review.

PubMed

Zen Filho, Edson Virgílio; Tolentino, Elen de Souza; Santos, Paulo Sérgio Silva

2016-04-01

The purpose of this systematic review was to evaluate the safety of dental implants placed in irradiated bone and to discuss their viability when placed post-radiotherapy (RT). A systematic review was performed to answer the questions: "Are dental implants in irradiated bone viable?" and "What are the main factors that influence the loss of implants in irradiated patients?" The search strategy resulted in 8 publications. A total of 331 patients received 1237 implants, with an overall failure rate of 9.53%. The osseointegration success rates ranged between 62.5% and 100%. The optimal time interval between irradiation and dental implantation varied from 6 to 15 months. The interval time between RT and implant placement and the radiation doses are not associated with significant implant failure rates. The placement of implants in irradiated bone is viable, and head and neck RT should not be considered as a contraindication for dental rehabilitation with implants. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2229-E2240, 2016. © 2015 Wiley Periodicals, Inc.

Development and experimental study of large size composite plasma immersion ion implantation device

NASA Astrophysics Data System (ADS)

Falun, SONG; Fei, LI; Mingdong, ZHU; Langping, WANG; Beizhen, ZHANG; Haitao, GONG; Yanqing, GAN; Xiao, JIN

2018-01-01

Plasma immersion ion implantation (PIII) overcomes the direct exposure limit of traditional beam-line ion implantation, and is suitable for the treatment of complex work-piece with large size. PIII technology is often used for surface modification of metal, plastics and ceramics. Based on the requirement of surface modification of large size insulating material, a composite full-directional PIII device based on RF plasma source and metal plasma source is developed in this paper. This device can not only realize gas ion implantation, but also can realize metal ion implantation, and can also realize gas ion mixing with metal ions injection. This device has two metal plasma sources and each metal source contains three cathodes. Under the condition of keeping the vacuum unchanged, the cathode can be switched freely. The volume of the vacuum chamber is about 0.94 m3, and maximum vacuum degree is about 5 × 10-4 Pa. The density of RF plasma in homogeneous region is about 109 cm-3, and plasma density in the ion implantation region is about 1010 cm-3. This device can be used for large-size sample material PIII treatment, the maximum size of the sample diameter up to 400 mm. The experimental results show that the plasma discharge in the device is stable and can run for a long time. It is suitable for surface treatment of insulating materials.

A power-efficient communication system between brain-implantable devices and external computers.

PubMed

Yao, Ning; Lee, Heung-No; Chang, Cheng-Chun; Sclabassi, Robert J; Sun, Mingui

2007-01-01

In this paper, we propose a power efficient communication system for linking a brain-implantable device to an external system. For battery powered implantable devices, the processor and the transmitter power should be reduced in order to both conserve battery power and reduce the health risks associated with transmission. To accomplish this, a joint source-channel coding/decoding system is devised. Low-density generator matrix (LDGM) codes are used in our system due to their low encoding complexity. The power cost for signal processing within the implantable device is greatly reduced by avoiding explicit source encoding. Raw data which is highly correlated is transmitted. At the receiver, a Markov chain source correlation model is utilized to approximate and capture the correlation of raw data. A turbo iterative receiver algorithm is designed which connects the Markov chain source model to the LDGM decoder in a turbo-iterative way. Simulation results show that the proposed system can save up to 1 to 2.5 dB on transmission power.

A new one-step procedure for pulmonary valve implantation of the melody valve: Simultaneous prestenting and valve implantation.

PubMed

Boudjemline, Younes

2018-01-01

To describe a new modification, the one-step procedure, that allows interventionists to pre-stent and implant a Melody valve simultaneously. Percutaneous pulmonary valve implantation (PPVI) is the standard of care for managing patients with dysfunctional right ventricular outflow tract, and the approach is standardized. Patients undergoing PPVI using the one-step procedure were identified in our database. Procedural data and radiation exposure were compared to those in a matched group of patients who underwent PPVI using the conventional two-step procedure. Between January 2016 and January 2017, PPVI was performed in 27 patients (median age/range, 19.1/10-55 years) using the one-step procedure involving manual crimping of one to three bare metal stents over the Melody valve. The stent and Melody valve were delivered successfully using the Ensemble delivery system. No complications occurred. All patients had excellent hemodynamic results (median/range post-PPVI right ventricular to pulmonary artery gradient, 9/0-20 mmHg). Valve function was excellent. Median procedural and fluoroscopic times were 56 and 10.2 min, respectively, which significantly differed from those of the two-step procedure group. Similarly, the dose area product (DAP), and radiation time were statistically lower in the one-step group than in the two-step group (P < 0.001 for all variables). After a median follow-up of 8 months (range, 3-14.7), no patient underwent reintervention, and no device dysfunction was observed. The one-step procedure is a safe modification that allows interventionists to prestent and implants the Melody valve simultaneously. It significantly reduces procedural and fluoroscopic times, and radiation exposure. © 2017 Wiley Periodicals, Inc.

Properties of arsenic-implanted Hg1-xCdxTe MBE films

NASA Astrophysics Data System (ADS)

Izhnin, Igor I.; Voitsekhovskii, Alexandr V.; Korotaev, Alexandr G.; Fitsych, Olena I.; Bonchyk, Oleksandr Yu.; Savytskyy, Hrygory V.; Mynbaev, Karim D.; Varavin, Vasilii S.; Dvoretsky, Sergey A.; Yakushev, Maxim V.; Jakiela, Rafal; Trzyna, Malgorzata

2017-01-01

Defect structure of arsenic-implanted Hg1-xCdxTe films (x=0.23-0.30) grown with molecular-beam epitaxy on Si substrates was investigated with the use of optical methods and by studying the electrical properties of the films. The structural perfection of the films remained higher after implantation with more energetic arsenic ions (350 keV vs 190 keV). 100%-activation of implanted ions as a result of post-implantation annealing was achieved, as well as the effective removal of radiation-induced donor defects. In some samples, however, activation of acceptor-like defects not related to mercury vacancies as a result of annealing was observed, possibly related to the effect of the substrate.

The dosimetry of brachytherapy-induced erectile dysfunction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merrick, Gregory S.; Butler, Wayne M

2003-12-31

There is emerging evidence that brachytherapy-induced erectile dysfunction (ED) is technique-related and may be minimized by careful attention to source placement. Herein, we review the relationship between radiation doses to the prostate gland/surrounding structures and the development of brachytherapy-induced ED. The permanent prostate brachytherapy literature was reviewed using MEDLINE searches to ensure completeness. Although the site-specific structure associated with brachytherapy-induced ED remains unknown, there is an increasing body of data implicating the proximal penis. With day 0 CT-based dosimetry, the dose to 50% (D{sub 50}) and 25% (D{sub 25}) of the bulb of the penis should be maintained below 40%more » and 60% mPD, respectively, while the crura D{sub 50} should be maintained below 28% mPD to maximize post-brachytherapy potency. To date, there is no data to suggest that either radiation doses to the neurovascular bundles or choice of isotope is associated with brachytherapy-induced ED, while conflicting data has been reported regarding radiation dose to the prostate and the use of supplemental external beam radiation therapy. Although the etiology of brachytherapy-induced ED is likely multifactorial, the available data supports the proximal penis as an important site-specific structure. Refinements in implant technique, including preplanning and intraoperative seed placement, will result in lower radiation doses to the proximal penis with potential improvement in potency preservation.« less

Role of step size and max dwell time in anatomy based inverse optimization for prostate implants

PubMed Central

Manikandan, Arjunan; Sarkar, Biplab; Rajendran, Vivek Thirupathur; King, Paul R.; Sresty, N.V. Madhusudhana; Holla, Ragavendra; Kotur, Sachin; Nadendla, Sujatha

2013-01-01

In high dose rate (HDR) brachytherapy, the source dwell times and dwell positions are vital parameters in achieving a desirable implant dose distribution. Inverse treatment planning requires an optimal choice of these parameters to achieve the desired target coverage with the lowest achievable dose to the organs at risk (OAR). This study was designed to evaluate the optimum source step size and maximum source dwell time for prostate brachytherapy implants using an Ir-192 source. In total, one hundred inverse treatment plans were generated for the four patients included in this study. Twenty-five treatment plans were created for each patient by varying the step size and maximum source dwell time during anatomy-based, inverse-planned optimization. Other relevant treatment planning parameters were kept constant, including the dose constraints and source dwell positions. Each plan was evaluated for target coverage, urethral and rectal dose sparing, treatment time, relative target dose homogeneity, and nonuniformity ratio. The plans with 0.5 cm step size were seen to have clinically acceptable tumor coverage, minimal normal structure doses, and minimum treatment time as compared with the other step sizes. The target coverage for this step size is 87% of the prescription dose, while the urethral and maximum rectal doses were 107.3 and 68.7%, respectively. No appreciable difference in plan quality was observed with variation in maximum source dwell time. The step size plays a significant role in plan optimization for prostate implants. Our study supports use of a 0.5 cm step size for prostate implants. PMID:24049323

Improved microstructure and properties of 12Cr2Ni4A alloy steel by vacuum carburization and Ti + N co-implantation

NASA Astrophysics Data System (ADS)

Dong, Meiling; Cui, Xiufang; Jin, Guo; Wang, Haidou; Cai, Zhaobing; Song, Shengqiang

2018-05-01

The carburized 12Cr2Ni4A alloy steel was implanted by Ti + N double elements implantation. The microstructure, nano-hardness and corrosion properties were investigated by EPMA, TEM, XPS, nano-hardness and electrochemistry tests in detail. The results showed that the Ti + N co-implanted layer is composed of FCC TiN and TiC phases with BCC martensite. Compared with the un-implanted layer, the Ti + N implanted layer has higher nano-hardness and better corrosion resistance. In addition, the higher nano-hardness was presented below the surface of 1800 nm compared with un-implanted layer, which is far beyond the thickness of the implanted layer. The results also indicated that the generation of nanoscale ceramic phase and structures are not the only factor to impose the influence on the nano-hardness and corrosion resistance, but the radiation damage and lattice distortion will play an important role.

Diagnostic imaging of trabecular bone microstructure for oral implants: a literature review.

PubMed

Ibrahim, N; Parsa, A; Hassan, B; van der Stelt, P; Wismeijer, D

2013-01-01

Several dental implant studies have reported that radiographic evaluation of bone quality can aid in reducing implant failure. Bone quality is assessed in terms of its quantity, density, trabecular characteristics and cells. Current imaging modalities vary widely in their efficiency in assessing trabecular structures, especially in a clinical setting. Most are very costly, require an extensive scanning procedure coupled with a high radiation dose and are only partially suitable for patient use. This review examines the current literature regarding diagnostic imaging assessment of trabecular microstructure prior to oral implant placement and suggests cone beam CT as a method of choice for evaluating trabecular bone microstructure.

[Principles of energy sources of totally implantable hearing aids for inner ear hearing loss].

PubMed

Baumann, J W; Leysieffer, H

1998-02-01

A fully implantable hearing aid consists of a sound receptor (microphone), an electronic amplifier including active audio-signal processing, an electromechanical transducer (actuator) for stimulating the ear by vibration, and an energy source. The energy source may be either a primary cell or a rechargeable (secondary) cell. As the energy requirements of an implantable hearing aid are dependent on the operating principle of the actuator, the operating principles of electromagnetic and piezoelectric transducers were examined with respect to their relative power consumption. The analysis showed that the energy requirements of an implantable hearing aid are significantly increased when an electromagnetic transducer is used. The power consumption of a piezoelectric transducer was found to be less than that of the electronic components alone. The energy needed to run a fully implantable hearing aid under these conditions would be 38 mWH per day. Primary cells cannot provide the energy needed for a minimum operation time of 5 years (70 WH), and therefore rechargeable cells must be used. A theoretical appraisal was carried out on nickel-cadmium, nickel-metal hydride, and lithium-ion cells to determine their suitability as well as to assess the risks associated with their use in an implant. Safety measures were drawn up from the results. Ni-MH cells were found to be the most suitable for use as an energy source for implantable hearing-aids because they are more robust than Li ion cells and their storage capacity is double that of Ni-Cd cells of similar size.

Sound Source Localization and Speech Understanding in Complex Listening Environments by Single-sided Deaf Listeners After Cochlear Implantation.

PubMed

Zeitler, Daniel M; Dorman, Michael F; Natale, Sarah J; Loiselle, Louise; Yost, William A; Gifford, Rene H

2015-09-01

To assess improvements in sound source localization and speech understanding in complex listening environments after unilateral cochlear implantation for single-sided deafness (SSD). Nonrandomized, open, prospective case series. Tertiary referral center. Nine subjects with a unilateral cochlear implant (CI) for SSD (SSD-CI) were tested. Reference groups for the task of sound source localization included young (n = 45) and older (n = 12) normal-hearing (NH) subjects and 27 bilateral CI (BCI) subjects. Unilateral cochlear implantation. Sound source localization was tested with 13 loudspeakers in a 180 arc in front of the subject. Speech understanding was tested with the subject seated in an 8-loudspeaker sound system arrayed in a 360-degree pattern. Directionally appropriate noise, originally recorded in a restaurant, was played from each loudspeaker. Speech understanding in noise was tested using the Azbio sentence test and sound source localization quantified using root mean square error. All CI subjects showed poorer-than-normal sound source localization. SSD-CI subjects showed a bimodal distribution of scores: six subjects had scores near the mean of those obtained by BCI subjects, whereas three had scores just outside the 95th percentile of NH listeners. Speech understanding improved significantly in the restaurant environment when the signal was presented to the side of the CI. Cochlear implantation for SSD can offer improved speech understanding in complex listening environments and improved sound source localization in both children and adults. On tasks of sound source localization, SSD-CI patients typically perform as well as BCI patients and, in some cases, achieve scores at the upper boundary of normal performance.

Wireless implantable chip with integrated nitinol-based pump for radio-controlled local drug delivery.

PubMed

Fong, Jeffrey; Xiao, Zhiming; Takahata, Kenichi

2015-02-21

We demonstrate an active, implantable drug delivery device embedded with a microfluidic pump that is driven by a radio-controlled actuator for temporal drug delivery. The polyimide-packaged 10 × 10 × 2 mm(3) chip contains a micromachined pump chamber and check valves of Parylene C to force the release of the drug from a 76 μL reservoir by wirelessly activating the actuator using external radio-frequency (RF) electromagnetic fields. The rectangular-shaped spiral-coil actuator based on nitinol, a biocompatible shape-memory alloy, is developed to perform cantilever-like actuation for pumping operation. The nitinol-coil actuator itself forms a passive 185 MHz resonant circuit that serves as a self-heat source activated via RF power transfer to enable frequency-selective actuation and pumping. Experimental wireless operation of fabricated prototypes shows successful release of test agents from the devices placed in liquid and excited by radiating tuned RF fields with an output power of 1.1 W. These tests reveal a single release volume of 219 nL, suggesting a device's capacity of ~350 individual ejections of drug from its reservoir. The thermal behavior of the activated device is also reported in detail. This proof-of-concept prototype validates the effectiveness of wireless RF pumping for fully controlled, long-lasting drug delivery, a key step towards enabling patient-tailored, targeted local drug delivery through highly miniaturized implants.

Binaural Processing of Multiple Sound Sources

DTIC Science & Technology

2016-08-18

Sound Source Localization Identification, and Sound Source Localization When Listeners Move. The CI research was also supported by an NIH grant...8217Cochlear Implant Performance in Realistic Listening Environments,’ Dr. Michael Dorman, Principal Investigator, Dr. William Yost unpaid advisor. The other... Listeners Move. The CI research was also supported by an NIH grant (“Cochlear Implant Performance in Realistic Listening Environments,” Dr. Michael Dorman

Fabrication of Total-Dose-Radiation-Hardened (TDRH) SOI wafer with embedded silicon nanoclusters

NASA Astrophysics Data System (ADS)

Wu, Aimin; Wang, Xi; Wei, Xing; Chen, Jing; Chen, Ming; Zhang, Zhengxuan

2009-05-01

Si ion-implantation and post annealing of silicon wafers prior to wafer bonding were used to radiation-harden the thermal oxide layer of Silicon on Insulator structures. After grinding and polishing, Total-Dose-Radiation-Hardened SOI (TDRH-SOI) wafers with several-micron-thick device layers were prepared. Electrical characterization before and after X-ray irradiation showed that the flatband voltage shift induced by irradiation was reduced by this preprocessing. Photoluminescence Spectroscopy (PL), Transmission Electron Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) results indicated that the improvement of the total dose response of the TDRH-SOI wafer was associated with formation of Si nanoclusters in the implanted oxide layer, suggesting that these were the likely candidates for electron and proton trapping centers that reduce the positive charge buildup effect in the buried oxide.

Structural Transformations in Austenitic Stainless Steel Induced by Deuterium Implantation: Irradiation at 295 K

NASA Astrophysics Data System (ADS)

Morozov, Oleksandr; Zhurba, Volodymir; Neklyudov, Ivan; Mats, Oleksandr; Progolaieva, Viktoria; Boshko, Valerian

2016-02-01

Deuterium thermal desorption spectra were investigated on the samples of austenitic steel 18Cr10NiTi pre-implanted at 295 K with deuterium ions in the dose range from 8 × 1014 to 2.7 × 1018 D/cm2. The kinetics of structural transformation development in the steel layer was traced from deuterium thermodesorption spectra as a function of deuterium concentration. Three characteristic regions with different low rates of deuterium amount desorption as the implantation dose increases were revealed: I—the linear region of low implantation doses (up to 1 × 1017 D/cm2); II—the nonlinear region of medium implantation doses (1 × 1017 to 8 × 1017 D/cm2); III—the linear region of high implantation doses (8 × 1017 to 2.7 × 1018 D/cm2). During the process of deuterium ion irradiation, the coefficient of deuterium retention in steel varies in discrete steps. Each of the discrete regions of deuterium retention coefficient variation corresponds to different implanted-matter states formed during deuterium ion implantation. The low-dose region is characterized by formation of deuterium-vacancy complexes and solid-solution phase state of deuterium in the steel. The total concentration of the accumulated deuterium in this region varies between 2.5 and 3 at.%. The medium-dose region is characterized by the radiation-induced action on the steel in the presence of deuterium with the resulting formation of the energy-stable nanosized crystalline structure of steel, having a developed network of intercrystalline boundaries. The basis for this developed network of intercrystalline boundaries is provided by the amorphous state, which manifests itself in the thermodesorption spectra as a widely temperature-scale extended region of deuterium desorption (structure formation with a varying activation energy). The total concentration of the accumulated deuterium in the region of medium implantation doses makes 7 to 8 at.%. The resulting structure shows stability against the action of deuterium ion implantation. This manifests itself in a nearly complete ceasing of deuterium accumulation from a newly implanted dose (radiation-resistant structure).

Systematic study of target localization for bioluminescence tomography guided radiation therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Jingjing; Zhang, Bin; Reyes, Juvenal

Purpose: To overcome the limitation of CT/cone-beam CT (CBCT) in guiding radiation for soft tissue targets, the authors developed a spectrally resolved bioluminescence tomography (BLT) system for the small animal radiation research platform. The authors systematically assessed the performance of the BLT system in terms of target localization and the ability to resolve two neighboring sources in simulations, tissue-mimicking phantom, and in vivo environments. Methods: Multispectral measurements acquired in a single projection were used for the BLT reconstruction. The incomplete variables truncated conjugate gradient algorithm with an iterative permissible region shrinking strategy was employed as the optimization scheme to reconstructmore » source distributions. Simulation studies were conducted for single spherical sources with sizes from 0.5 to 3 mm radius at depth of 3–12 mm. The same configuration was also applied for the double source simulation with source separations varying from 3 to 9 mm. Experiments were performed in a standalone BLT/CBCT system. Two self-illuminated sources with 3 and 4.7 mm separations placed inside a tissue-mimicking phantom were chosen as the test cases. Live mice implanted with single-source at 6 and 9 mm depth, two sources at 3 and 5 mm separation at depth of 5 mm, or three sources in the abdomen were also used to illustrate the localization capability of the BLT system for multiple targets in vivo. Results: For simulation study, approximate 1 mm accuracy can be achieved at localizing center of mass (CoM) for single-source and grouped CoM for double source cases. For the case of 1.5 mm radius source, a common tumor size used in preclinical study, their simulation shows that for all the source separations considered, except for the 3 mm separation at 9 and 12 mm depth, the two neighboring sources can be resolved at depths from 3 to 12 mm. Phantom experiments illustrated that 2D bioluminescence imaging failed to distinguish two sources, but BLT can provide 3D source localization with approximately 1 mm accuracy. The in vivo results are encouraging that 1 and 1.7 mm accuracy can be attained for the single-source case at 6 and 9 mm depth, respectively. For the 2 sources in vivo study, both sources can be distinguished at 3 and 5 mm separations, and approximately 1 mm localization accuracy can also be achieved. Conclusions: This study demonstrated that their multispectral BLT/CBCT system could be potentially applied to localize and resolve multiple sources at wide range of source sizes, depths, and separations. The average accuracy of localizing CoM for single-source and grouped CoM for double sources is approximately 1 mm except deep-seated target. The information provided in this study can be instructive to devise treatment margins for BLT-guided irradiation. These results also suggest that the 3D BLT system could guide radiation for the situation with multiple targets, such as metastatic tumor models.« less

He-irradiation effects on glass-ceramics for joining of SiC-based materials

NASA Astrophysics Data System (ADS)

Gozzelino, L.; Casalegno, V.; Ghigo, G.; Moskalewicz, T.; Czyrska-Filemonowicz, A.; Ferraris, M.

2016-04-01

CaO-Al2O3 (CA) and SiO2-Al2O3-Y2O3 (SAY) glass-ceramics are promising candidates for SiC/SiC indirect joints. In view of their use in locations where high radiation level is expected (i.e. fusion plants) it is important to investigate how radiation-induced damage can modify the material microstructure. To this aim, pellets of both types were irradiated with 5.5 MeV 4He+ ions at an average temperature of 75 °C up to a fluence of almost 2.3·1018 cm-2. This produces a displacement defect density that increases with depth and reaches a value of about 40 displacements per atom in the ion implantation region, where the He-gas reaches a concentration of several thousands of atomic parts per million. X-ray diffractometry and scanning electron microscopy showed no change in the microstructure and in the morphology of the pellet surface. Moreover, a transmission electron microscopy investigation on cross-section lamellas revealed the occurrence of structural defects and agglomerates of He-bubbles in the implantation region for the CA sample and a more homogeneous He-bubble distribution in the SAY pellet, even outside the implantation layer. In addition, no amorphization was found in both samples, even in correspondence to the He implantation zone. The radiation damage induced only occasional micro-cracks, mainly located at grain boundaries (CA) or within the grains (SAY).

Implanted Cardiac Defibrillator Care in Radiation Oncology Patient Population

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gelblum, Daphna Y.; Amols, Howard

2009-04-01

Purpose: To review the experience of a large cancer center with radiotherapy (RT) patients bearing implantable cardiac defibrillators (ICDs) to propose some preliminary care guidelines as we learn more about the devices and their interaction with the therapeutic radiation environment. Methods and Materials: We collected data on patients with implanted ICDs treated with RT during a 2.5-year period at any of the five Memorial Sloan-Kettering clinical campuses. Information regarding the model, location, and dose detected from the device, as well as the treatment fields, fraction size, and treatment energy was collected. During this time, a new management policy for thesemore » patients had been implemented requiring treatment with low-energy beams (6 MV) and close surveillance of the patients in partnership with their electrophysiologist, as they received RT. Results: During the study period, 33 patients were treated with an ICD in place. One patient experienced a default of the device to its initial factory setting that was detected by the patient hearing an auditory signal from the device. This patient had initially been treated with a 15-MV beam. After this episode, his treatment was replanned to be completed with 6-MV photons, and he experienced no further events. Conclusion: Patients with ICDs and other implanted computer-controlled devices will be encountered more frequently in the RT department, and proper management is important. We present a policy for the safe treatment of these patients in the radiation oncology environment.« less

SEMICONDUCTOR TECHNOLOGY: Influence of nitrogen dose on the charge density of nitrogen-implanted buried oxide in SOI wafers

NASA Astrophysics Data System (ADS)

Zhongshan, Zheng; Zhongli, Liu; Ning, Li; Guohua, Li; Enxia, Zhang

2010-02-01

To harden silicon-on-insulator (SOI) wafers fabricated using separation by implanted oxygen (SIMOX) to total-dose irradiation, the technique of nitrogen implantation into the buried oxide (BOX) layer of SIMOX wafers can be used. However, in this work, it has been found that all the nitrogen-implanted BOX layers reveal greater initial positive charge densities, which increased with increasing nitrogen implantation dose. Also, the results indicate that excessively large nitrogen implantation dose reduced the radiation tolerance of BOX for its high initial positive charge density. The bigger initial positive charge densities can be ascribed to the accumulation of implanted nitrogen near the Si-BOX interface after annealing. On the other hand, in our work, it has also been observed that, unlike nitrogen-implanted BOX, all the fluorine-implanted BOX layers show a negative charge density. To obtain the initial charge densities of the BOX layers, the tested samples were fabricated with a metal-BOX-silicon (MBS) structure based on SIMOX wafers for high-frequency capacitance-voltage (C-V) analysis.

A method for verification of treatment delivery in HDR prostate brachytherapy using a flat panel detector for both imaging and source tracking.

PubMed

Smith, Ryan L; Haworth, Annette; Panettieri, Vanessa; Millar, Jeremy L; Franich, Rick D

2016-05-01

Verification of high dose rate (HDR) brachytherapy treatment delivery is an important step, but is generally difficult to achieve. A technique is required to monitor the treatment as it is delivered, allowing comparison with the treatment plan and error detection. In this work, we demonstrate a method for monitoring the treatment as it is delivered and directly comparing the delivered treatment with the treatment plan in the clinical workspace. This treatment verification system is based on a flat panel detector (FPD) used for both pre-treatment imaging and source tracking. A phantom study was conducted to establish the resolution and precision of the system. A pretreatment radiograph of a phantom containing brachytherapy catheters is acquired and registration between the measurement and treatment planning system (TPS) is performed using implanted fiducial markers. The measured catheter paths immediately prior to treatment were then compared with the plan. During treatment delivery, the position of the (192)Ir source is determined at each dwell position by measuring the exit radiation with the FPD and directly compared to the planned source dwell positions. The registration between the two corresponding sets of fiducial markers in the TPS and radiograph yielded a registration error (residual) of 1.0 mm. The measured catheter paths agreed with the planned catheter paths on average to within 0.5 mm. The source positions measured with the FPD matched the planned source positions for all dwells on average within 0.6 mm (s.d. 0.3, min. 0.1, max. 1.4 mm). We have demonstrated a method for directly comparing the treatment plan with the delivered treatment that can be easily implemented in the clinical workspace. Pretreatment imaging was performed, enabling visualization of the implant before treatment delivery and identification of possible catheter displacement. Treatment delivery verification was performed by measuring the source position as each dwell was delivered. This approach using a FPD for imaging and source tracking provides a noninvasive method of acquiring extensive information for verification in HDR prostate brachytherapy.

A method for verification of treatment delivery in HDR prostate brachytherapy using a flat panel detector for both imaging and source tracking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Ryan L., E-mail: ryan.smith@wbrc.org.au; Millar, Jeremy L.; Franich, Rick D.

Purpose: Verification of high dose rate (HDR) brachytherapy treatment delivery is an important step, but is generally difficult to achieve. A technique is required to monitor the treatment as it is delivered, allowing comparison with the treatment plan and error detection. In this work, we demonstrate a method for monitoring the treatment as it is delivered and directly comparing the delivered treatment with the treatment plan in the clinical workspace. This treatment verification system is based on a flat panel detector (FPD) used for both pre-treatment imaging and source tracking. Methods: A phantom study was conducted to establish the resolutionmore » and precision of the system. A pretreatment radiograph of a phantom containing brachytherapy catheters is acquired and registration between the measurement and treatment planning system (TPS) is performed using implanted fiducial markers. The measured catheter paths immediately prior to treatment were then compared with the plan. During treatment delivery, the position of the {sup 192}Ir source is determined at each dwell position by measuring the exit radiation with the FPD and directly compared to the planned source dwell positions. Results: The registration between the two corresponding sets of fiducial markers in the TPS and radiograph yielded a registration error (residual) of 1.0 mm. The measured catheter paths agreed with the planned catheter paths on average to within 0.5 mm. The source positions measured with the FPD matched the planned source positions for all dwells on average within 0.6 mm (s.d. 0.3, min. 0.1, max. 1.4 mm). Conclusions: We have demonstrated a method for directly comparing the treatment plan with the delivered treatment that can be easily implemented in the clinical workspace. Pretreatment imaging was performed, enabling visualization of the implant before treatment delivery and identification of possible catheter displacement. Treatment delivery verification was performed by measuring the source position as each dwell was delivered. This approach using a FPD for imaging and source tracking provides a noninvasive method of acquiring extensive information for verification in HDR prostate brachytherapy.« less

Development of ion implanted gallium arsenide transistors

NASA Technical Reports Server (NTRS)

Hunsperger, R.; Baron, R.

1972-01-01

Techniques were developed for creating bipolar microwave transistors in GaAs by ion implantation doping. The electrical properties of doped layers produced by the implantation of the light ions Be, Mg, and S were studied. Be, Mg, and S are suitable for forming the relatively deep base-collector junction at low ion energies. The electrical characteristics of ion-implanted diodes of both the mesa and planar types were determined. Some n-p-n planar transistor structures were fabricated by implantation of Mg to form the base regions and Si to form the emitters. These devices were found to have reasonably good base-collector and emitter-base junctions, but the current gain beta was small. The low was attributable to radiative recombination in the base region, which was extremely wide.

Reliability systems for implantable cardiac defibrillator batteries

NASA Astrophysics Data System (ADS)

Takeuchi, Esther S.

The reliability of the power sources used in implantable cardiac defibrillators is critical due to the life-saving nature of the device. Achieving a high reliability power source depends on several systems functioning together. Appropriate cell design is the first step in assuring a reliable product. Qualification of critical components and of the cells using those components is done prior to their designation as implantable grade. Product consistency is assured by control of manufacturing practices and verified by sampling plans using both accelerated and real-time testing. Results to date show that lithium/silver vanadium oxide cells used for implantable cardiac defibrillators have a calculated maximum random failure rate of 0.005% per test month.

Post-treatment PSA < or = 0.2 ng/mL defines disease freedom after radiotherapy for prostate cancer using modern techniques.

PubMed

Critz, F A; Williams, W H; Holladay, C T; Levinson, A K; Benton, J B; Holladay, D A; Schnell, F J; Maxa, L S; Shrake, P D

1999-12-01

The prostate-specific antigen (PSA) definition of disease freedom after radiotherapy for prostate cancer is still in dispute. This report focuses on the PSA nadir achieved in men treated by modern radiotherapy techniques. From 1984 to 1994, 489 consecutive men with clinical Stage T1 -T2 prostate cancer were treated by simultaneous radiation: prostate iodine-125 implant followed by external beam radiation. A transperineal implant was performed on 143 men with Stage T1-T2NX, the focus of this study; 346 men with Stage T1-T2N0 had a retropubic implant. The median pretreatment PSA was 8.3 ng/mL (range 0.3 to 188). A rising PSA was defined as one that rose on three consecutive occasions above whatever nadir was achieved. A minimum 5-year follow-up (range 5 to 15) was reached by 453 men. After a minimum 5-year follow-up, 336 men had a nonrising PSA, and of this group, 107 had undergone simultaneous radiation by the transperineal implant technique. A PSA nadir of 0.2 ng/mL or less was achieved by 97% of the transperineally implanted men, and 3% had a nadir of 0.3 to 1.0 ng/mL. Of the 489 men, those who had a nadir of 0.2 ng/mL or less had a 92% nonrising PSA rate (P = 0.001) 10 years after treatment compared with a 41% rate for men who had a nadir of 0.3 to 1.0 ng/mL. All men whose nadir was greater than 1.0 ng/mL had recurrence. The median time to achieve the PSA nadir of 0.2 ng/mL was 27 months (range 3 to 102). Primarily on the basis of the results from men treated with simultaneous radiation using the transperineal technique, the definition of disease freedom for radiotherapy should be men who achieve and maintain a PSA nadir of 0.2 ng/mL or less.

Radioactive iodine-125 implantation for cancer of the prostate.

PubMed

Nag, S

1985-01-01

Localized cancer of the prostate can be treated by radical prostatectomy, external beam irradiation, or radioactive implantation with similar survival results. Radical prostatectomy, however, almost universally results in impotency, although a new, nerve-sparing procedure may preserve potency in B1 patients. External beam irradiation radiates a large volume of tissue with significant rectal and bladder morbidity, 23-47% risk of impotency, and requires prolonged treatment (6-8 weeks). Radioactive implantation may be done suprapubically or transperineally using iodine-125, gold-198, or radon-222 permanent implantation techniques and iridium-192 or radium-226 removable implantation techniques. Interstitial iodine-125 implantation is frequently employed since it is a short procedure and limits the morbidity to a 7% incidence of impotency, 20% urinary complications, and 5% rectal complications. The overall 5-year survival of patients with iodine-125 is 79%, the survival rate decreasing with increasing T or N stage or increasing grade of tumor.

Electroencephalographic responses to ionizing radiation.

PubMed

GARCIA, J; BUCHWALD, N A; BACH-Y-RITA, G; FEDER, B H; KOELLING, R A

1963-04-19

Electroencephalographic recordings made from chronically implanted cortical electrodes indicate that ionizing radiation has an immediate effect upon brain wave patterns. X-rays delivered at the rate of 0.2 roentgen per second produce an arousal effect resembling that which occurs as a result of stimulation through peripheral receptor systems.

Sensor-based electromagnetic navigation to facilitate implantation of left ventricular leads in cardiac resynchronization therapy.

PubMed

Döring, Michael; Sommer, Philipp; Rolf, Sascha; Lucas, Johannes; Breithardt, Ole A; Hindricks, Gerhard; Richter, Sergio

2015-02-01

Implantation of cardiac resynchronization therapy (CRT) devices can be challenging, time consuming, and fluoroscopy intense. To facilitate placement of left ventricular (LV) leads, a novel electromagnetic navigation system (MediGuide™, St. Jude Medical, St. Paul, MN, USA) has been developed, displaying real-time 3-D location of sensor-embedded delivery tools superimposed on prerecorded X-ray cine-loops of coronary sinus venograms. We report our experience and advanced progress in the use of this new electromagnetic tracking system to guide LV lead implantation. Between January 2012 and December 2013, 71 consecutive patients (69 ± 9 years, 76% male) were implanted with a CRT device using the new electromagnetic tracking system. Demographics, procedural data, and periprocedural adverse events were gathered. The impact of the operator's experience, optimized workflow, and improved software technology on procedural data were analyzed. LV lead implantation was successfully achieved in all patients without severe adverse events. Total procedure time measured 87 ± 37 minutes and the median total fluoroscopy time (skin-to-skin) was 4.9 (2.5-7.8) minutes with a median dose-area-product of 476 (260-1056) cGy*cm(2) . An additional comparison with conventional CRT device implantations showed a significant reduction in fluoroscopy time from 8.0 (5.8; 11.5) to 4.5 (2.8; 7.3) minutes (P = 0.016) and radiation dose from 603 (330; 969) to 338 (176; 680) cGy*cm(2) , respectively (P = 0.044 ). Use of the new navigation system enables safe and successful LV lead placement with improved orientation and significantly reduced radiation exposure during CRT implantation. © 2014 Wiley Periodicals, Inc.

Establishing High-Quality Prostate Brachytherapy Using a Phantom Simulator Training Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thaker, Nikhil G.; Kudchadker, Rajat J.; Swanson, David A.

2014-11-01

Purpose: To design and implement a unique training program that uses a phantom-based simulator to teach the process of prostate brachytherapy (PB) quality assurance and improve the quality of education. Methods and Materials: Trainees in our simulator program were practicing radiation oncologists, radiation oncology residents, and fellows of the American Brachytherapy Society. The program emphasized 6 core areas of quality assurance: patient selection, simulation, treatment planning, implant technique, treatment evaluation, and outcome assessment. Using the Iodine 125 ({sup 125}I) preoperative treatment planning technique, trainees implanted their ultrasound phantoms with dummy seeds (ie, seeds with no activity). Pre- and postimplant dosimetric parametersmore » were compared and correlated using regression analysis. Results: Thirty-one trainees successfully completed the simulator program during the period under study. The mean phantom prostate size, number of seeds used, and total activity were generally consistent between trainees. All trainees met the V100 >95% objective both before and after implantation. Regardless of the initial volume of the prostate phantom, trainees' ability to cover the target volume with at least 100% of the dose (V100) was not compromised (R=0.99 pre- and postimplant). However, the V150 had lower concordance (R=0.37) and may better reflect heterogeneity control of the implant process. Conclusions: Analysis of implants from this phantom-based simulator shows a high degree of consistency between trainees and uniformly high-quality implants with respect to parameters used in clinical practice. This training program provides a valuable educational opportunity that improves the quality of PB training and likely accelerates the learning curve inherent in PB. Prostate phantom implantation can be a valuable first step in the acquisition of the required skills to safely perform PB.« less

Immediate breast reconstruction with anatomical implants following mastectomy: The radiation perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ben-David, Merav, E-mail: Merav.ben-david@sheba.health.gov.il; Sackler School of Medicine, Tel Aviv University, Tel Aviv; Granot, Hila

2016-07-01

Immediate implant-based breast reconstruction followed by postmastectomy radiation therapy (PMRT) is controversial because of the risk of compromised treatment plans and concerns regarding cosmetic outcomes. We evaluated the effects of immediate direct-to-implant breast reconstruction with anatomical implants on the quality of PMRT delivered by 3-dimensional conformal radiotherapy (3D-CRT). In this retrospective, single-institution study, patients who had undergone reconstruction with direct anatomic implant, performed by a single surgeon, received 3D-CRT between 2008 and 2013. For each patient, 2 plans (including or excluding internal mammary nodes [IMN]) were created and calculated. The primary end point was the dose distribution among reconstructed breasts,more » heart, lungs, and IMNs, and between right and left breasts. Of 29 consecutive patients, 11 received right-sided and 18 received left-sided PMRT to a total dose of 50 Gy. For plans excluding IMN coverage, mean D{sub mean} for right and left reconstructed breasts was 49.09 Gy (98.2% of the prescribed dose) and 48.51 Gy (97.0%), respectively. For plans including IMNs, mean D{sub mean} was 49.15 Gy (98.3%) for right and 48.46 Gy (96.9%) for left reconstructed breasts; the mean IMN D{sub mean} was 47.27 Gy (right) and 47.89 Gy (left). Heart D{sub mean} was below 1.56 Gy for all plans. Mean total lung volume receiving a dose of ≥ 20 Gy was 13.80% to 19.47%. PMRT can be delivered effectively and safely by 3D-CRT after direct-to-implant breast reconstruction with anatomical implants, even if patients require IMN treatment.« less

Cardiovascular ultrasonography detection of embolic sources in trauma.

PubMed

Saranteas, Theodosios; Mavrogenis, Andreas F; Poularas, John; Kostroglou, Andreas; Mandila, Christina; Panou, Fotios

2018-06-01

Venous thromboembolism (deep vein thrombosis and pulmonary embolism) and bone cement implantation syndrome are major sources of embolic events in trauma patients. In these patients, embolic events due to venous thromboembolism and bone cement implantation syndrome have been detected with cardiac and vascular ultrasonography in the emergency setting, during the perioperative period, and in the intensive care unit. This article discusses the ultrasonography modalities and imaging findings of embolic events related to venous thromboembolism and bone cement implantation syndrome. The aim is to present a short review with exceptional illustrations that can enable physicians to identify sources of emboli in trauma patients with cardiovascular ultrasonography. Copyright © 2018 Elsevier Inc. All rights reserved.

Cochlear implants in children implanted in Jordan: A parental overview.

PubMed

Alkhamra, Rana A

2015-07-01

Exploring the perspective of parents on the cochlear implant process in Jordan. Sixty parents of deaf children were surveyed on the information gathering process prior to cochlear implant surgery, and their implant outcome expectations post-surgery. Whether child or parent characteristics may impact parents' post-surgical expectations was explored. Although parents used a variety of information sources when considering a cochlear implant, the ear, nose and throat doctor comprised their major source of information (60%). Parents received a range of information prior to cochlear implant but agreed (93.3%) on the need for a multidisciplinary team approach. Post-surgically, parents' expected major developments in the areas of spoken language (97%), and auditory skills (100%). Receiving education in mainstream schools (92%) was expected too. Parents perceived the cochlear implant decision as the best decision they can make for their child (98.3%). A significant correlation was found between parents contentment with the cochlear implant decision and expecting developments in the area of reading and writing (r=0.7). Child's age at implantation and age at hearing loss diagnosis significantly affected parents' post-implant outcome expectations (p<0.05). Despite the general satisfaction from the information quantity and quality prior to cochlear implant, parents agree on the need for a comprehensive multidisciplinary team approach during the different stages of the cochlear implant process. Parents' education about cochlear implants prior to the surgery can affect their post-surgical outcome expectations. The parental perspective presented in this study can help professionals develop better understanding of parents' needs and expectations and henceforth improve their services and support during the different stages of the cochlear implant process. Copyright © 2015. Published by Elsevier Ireland Ltd.

In vitro biological outcome of laser application for modification or processing of titanium dental implants.

PubMed

Hindy, Ahmed; Farahmand, Farzam; Tabatabaei, Fahimeh Sadat

2017-07-01

There are numerous functions for laser in modern implant dentistry including surface treatment, surface coating, and implant manufacturing. As laser application may potentially improve osseointegration of dental implants, we systematically reviewed the literature for in vitro biological responses to laser-modified or processed titanium dental implants. The literature was searched in PubMed, ISI Web, and Scopus, using keywords "titanium dental implants," "laser," "biocompatibility," and their synonyms. After screening the 136 references obtained, 28 articles met the inclusion criteria. We found that Nd:YAG laser was the most commonly used lasers in the treatment or processing of titanium dental implants. Most of the experiments used cell attachment and cell proliferation to investigate bioresponses of the implants. The most commonly used cells in these assays were osteoblast-like cells. Only one study was conducted in stem cells. These in vitro studies reported higher biocompatibility in laser-modified titanium implants. It seems that laser radiation plays a vital role in cell response to dental implants; however, it is necessary to accomplish more studies using different laser types and parameters on various cells to offer a more conclusive result.

Near-infrared fluorescence imaging platform for quantifying in vivo nanoparticle diffusion from drug loaded implants.

PubMed

Markovic, Stacey; Belz, Jodi; Kumar, Rajiv; Cormack, Robert A; Sridhar, Srinivas; Niedre, Mark

2016-01-01

Drug loaded implants are a new, versatile technology platform to deliver a localized payload of drugs for various disease models. One example is the implantable nanoplatform for chemo-radiation therapy where inert brachytherapy spacers are replaced by spacers doped with nanoparticles (NPs) loaded with chemotherapeutics and placed directly at the disease site for long-term localized drug delivery. However, it is difficult to directly validate and optimize the diffusion of these doped NPs in in vivo systems. To better study this drug release and diffusion, we developed a custom macroscopic fluorescence imaging system to visualize and quantify fluorescent NP diffusion from spacers in vivo. To validate the platform, we studied the release of free fluorophores, and 30 nm and 200 nm NPs conjugated with the same fluorophores as a model drug, in agar gel phantoms in vitro and in mice in vivo. Our data verified that the diffusion volume was NP size-dependent in all cases. Our near-infrared imaging system provides a method by which NP diffusion from implantable nanoplatform for chemo-radiation therapy spacers can be systematically optimized (eg, particle size or charge) thereby improving treatment efficacy of the platform.

Defects in Arsenic Implanted p + -n- and n + -p- Structures Based on MBE Grown CdHgTe Films

NASA Astrophysics Data System (ADS)

Izhnin, I. I.; Fitsych, E. I.; Voitsekhovskii, A. V.; Korotaev, A. G.; Mynbaev, K. D.; Varavin, V. S.; Dvoretsky, S. A.; Mikhailov, N. N.; Yakushev, M. V.; Bonchyk, A. Yu.; Savytskyy, H. V.; Świątek, Z.

2018-02-01

Complex studies of the defect structure of arsenic-implanted (with the energy of 190 keV) Cd x Hg 1-x Te ( x = 0.22) films grown by molecular-beam epitaxy are carried out. The investigations were performed using secondary-ion mass spectroscopy, transmission electron microscopy, optical reflection in the visible region of the spectrum, and electrical measurements. Radiation donor defects were studied in n +- p- and n +- n-structures obtained by implantation and formed on the basis of p-type and n-type materials, respectively, without activation annealing. It is shown that in the layer of the distribution of implanted ions, a layer of large extended defects with low density is formed in the near-surface region followed by a layer of smaller extended defects with larger density. A different character of accumulation of electrically active donor defects in the films with and without a protective graded-gap surface layer has been revealed. It is demonstrated that p +- n- structures are formed on the basis of n-type material upon activation of arsenic in the process of postimplantation thermal annealing with 100% activation of impurity and complete annihilation of radiation donor defects.

Electromagnetic Compatibility of Transcutaneous Energy Transmission Systemfor Totally Implantable Artificial Heart

NASA Astrophysics Data System (ADS)

Shiba, Kenji; Koshiji, Kohji

Transcutaneous Energy Transmission (TET) is one way of providing the energy needed to power a totally implantable artificial heart (TIAH). In the present study, an externally coupled TET system was implanted in a prototype human phantom to evaluate emission and immunity. In the emission evaluation, measurements were conducted based on CISPR Pub.11 and VDE 0871 standards, while immunity tests were based on the standards of the IEC 61000-4 series. The magnetic field of the radiated emission was measured using a loop antenna. At 0.1[MHz], we found the greatest magnetic field of 47.8 [dBμA/m], somewhat less than CISPR’s upper limit of 54 [dBμA/m]. For the conducted emission, by installing a noise filter and ferrite beads in the input section of the DC-power supply, conducted emission could be kept within the allowable limits of CISPR Pub.11 and VDE 0871. Finally, the immunity tests against radiated and conducted emission, electrostatic discharge and voltage fluctuation proved that the prototype could withstand the maximum level of disturbance. These results confirmed that the TET system implanted in a human phantom could, through modification, meet the emission and immunity standards.

Anti-PD-1 Blockade and Stereotactic Radiation Produce Long-Term Survival in Mice With Intracranial Gliomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Jing; See, Alfred P.; Phallen, Jillian

2013-06-01

Purpose: Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, and radiation is one of the main treatment modalities. However, cure rates remain low despite best available therapies. Immunotherapy is a promising modality that could work synergistically with radiation, which has been shown to increase antigen presentation and promote a proinflammatory tumor microenvironment. Programmed-death-1 (PD-1) is a surface receptor expressed on activated and exhausted T cells, which mediate T cell inhibition upon binding with its ligand PD-L1, expressed on many tumor types including human GBMs. We tested the combination of anti-PD-1 immunotherapy with stereotactic radiosurgery in amore » mouse orthotopic GBM model. Methods and Materials: We performed intracranial implantation of mouse glioma cell line GL261 transfected with luciferase into C57BL/6 mice. Mice were stratified into 4 treatment groups: (1) control; (2) radiation only; (3) anti-PD-1 antibody only; and (4) radiation plus anti-PD-1 antibody. Overall survival was quantified. The mice were killed on day 21 after implantation to assess immunologic parameters in the brain/tumor, cervical lymph nodes, and spleen. Results: Improved survival was demonstrated with combination anti-PD-1 therapy plus radiation compared with either modality alone: median survival was 25 days in the control arm, 27 days in the anti-PD-1 antibody arm, 28 days in the radiation arm, and 53 days in the radiation plus anti-PD-1 therapy arm (P<.05 by log-rank Mantle-Cox). Long-term survival was seen only in the combined treatment arm, with a fraction (15%-40%) of animals alive at day 180+ after treatment. Immunologic data on day 21 after implantation showed increased tumor infiltration by cytotoxic T cells (CD8+/interferon-γ+/tumor necrosis factor-α+) and decreased regulatory T cells (CD4+/FOXP3) in the combined treatment group compared with the single modality arms. Conclusions: The combination of PD-1 blockade and localized radiation therapy results in long-term survival in mice with orthotopic brain tumors. These studies provide strong preclinical evidence to support combination trials in patients with GBM.« less

Dose reduction in LDR brachytherapy by implanted prostate gold fiducial markers.

PubMed

Landry, Guillaume; Reniers, Brigitte; Lutgens, Ludy; Murrer, Lars; Afsharpour, Hossein; de Haas-Kock, Danielle; Visser, Peter; van Gils, Francis; Verhaegen, Frank

2012-03-01

The dosimetric impact of gold fiducial markers (FM) implanted prior to external beam radiotherapy of prostate cancer on low dose rate (LDR) brachytherapy seed implants performed in the context of combined therapy was investigated. A virtual water phantom was designed containing a single FM. Single and multi source scenarios were investigated by performing Monte Carlo dose calculations, along with the influence of varying orientation and distance of the FM with respect to the sources. Three prostate cancer patients treated with LDR brachytherapy for a recurrence following external beam radiotherapy with implanted FM were studied as surrogate cases to combined therapy. FM and brachytherapy seeds were identified on post implant CT scans and Monte Carlo dose calculations were performed with and without FM. The dosimetric impact of the FM was evaluated by quantifying the amplitude of dose shadows and the volume of cold spots. D(90) was reported based on the post implant CT prostate contour. Large shadows are observed in the single source-FM scenarios. As expected from geometric considerations, the shadows are dependent on source-FM distance and orientation. Large dose reductions are observed at the distal side of FM, while at the proximal side a dose enhancement is observed. In multisource scenarios, the importance of shadows appears mitigated, although FM at the periphery of the seed distribution caused underdosage (

Polyquant CT: direct electron and mass density reconstruction from a single polyenergetic source

NASA Astrophysics Data System (ADS)

Mason, Jonathan H.; Perelli, Alessandro; Nailon, William H.; Davies, Mike E.

2017-11-01

Quantifying material mass and electron density from computed tomography (CT) reconstructions can be highly valuable in certain medical practices, such as radiation therapy planning. However, uniquely parameterising the x-ray attenuation in terms of mass or electron density is an ill-posed problem when a single polyenergetic source is used with a spectrally indiscriminate detector. Existing approaches to single source polyenergetic modelling often impose consistency with a physical model, such as water-bone or photoelectric-Compton decompositions, which will either require detailed prior segmentation or restrictive energy dependencies, and may require further calibration to the quantity of interest. In this work, we introduce a data centric approach to fitting the attenuation with piecewise-linear functions directly to mass or electron density, and present a segmentation-free statistical reconstruction algorithm for exploiting it, with the same order of complexity as other iterative methods. We show how this allows both higher accuracy in attenuation modelling, and demonstrate its superior quantitative imaging, with numerical chest and metal implant data, and validate it with real cone-beam CT measurements.

Radiation Halos, a Rare Microstructure in Diamonds From the Central African Republic

NASA Astrophysics Data System (ADS)

Vicenzi, E. P.; Heaney, P. J.; Snyder, K.; Armstrong, L.

2002-05-01

The geochemical characterization of bulk diamonds and associated inclusions as a tool for determining provenance carries significant inherent limitations. Isotopic and trace element signatures are imparted within the mantle during diamond growth; hence, discriminating crystals from a particular region on the Earth's surface on this basis is difficult at best, and impossible (using current technologies) in many cases. In contrast, rare diamond characteristics may provide a partial solution for recognizing stones from a limited number of localities. Here we discuss an analysis of radiation halos in alluvially deposited polycrystalline diamonds (carbonados) from the Central African Republic (CAR). Large amounts of implanted Xe and Kr, as well as isotopic ratios of those elements consistent with fission, in carbonado strongly suggest that diamond crystallization took place in the presence of significant quantities of uranium [1]. Such ionizing radiation ultimately results in the loss of periodicity of the diamond structure. Crystallographically damaged areas produce fewer photons in cathodoluminescence microscopy, and therefore, the metamict regions resulting from point source radiation in diamond can be visualized on the scale of ~1-25 micrometers [2]. Because intermediate daughter products in the decay chain release alpha particles at differing energies, a ``bull's eye'' pattern is produced in 2-D by the point source radiation. Radiation haloes have been previously observed in carbonados and are thought to result from U deposition associated with fluids following diamond formation [3,4]. We have made a series of measurements of the apparent diameter of the largest circle within a damage halo. By comparing the statistical distribution of this dimension to the distribution expected for a series of circles resulting from random sectioning of mono-sized spheres, one can estimate whether the radiation resulted from one or more fluid pulses widely separated in time. Preliminary data are consistent with a single pulse of uranium deposition in CAR carbonado. [1] Ozima et al. 1991, Nature 351 : 472. [2] Mendelssohn et al. 1979, Diamond Research:35. [3] Milledge et al. 1998, 7th Intl. Kimberlite Conf: 589. [4] Magee 2001, Ph.D. ANU 247p.

Influence of metallic dental implants and metal artefacts on dose calculation accuracy.

PubMed

Maerz, Manuel; Koelbl, Oliver; Dobler, Barbara

2015-03-01

Metallic dental implants cause severe streaking artefacts in computed tomography (CT) data, which inhibit the correct representation of shape and density of the metal and the surrounding tissue. The aim of this study was to investigate the impact of dental implants on the accuracy of dose calculations in radiation therapy planning and the benefit of metal artefact reduction (MAR). A second aim was to determine the treatment technique which is less sensitive to the presence of metallic implants in terms of dose calculation accuracy. Phantoms consisting of homogeneous water equivalent material surrounding dental implants were designed. Artefact-containing CT data were corrected using the correct density information. Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were calculated on corrected and uncorrected CT data and compared to 2-dimensional dose measurements using GafChromic™ EBT2 films. For all plans the accuracy of dose calculations is significantly higher if performed on corrected CT data (p = 0.015). The agreement of calculated and measured dose distributions is significantly higher for VMAT than for IMRT plans for calculations on uncorrected CT data (p = 0.011) as well as on corrected CT data (p = 0.029). For IMRT and VMAT the application of metal artefact reduction significantly increases the agreement of dose calculations with film measurements. VMAT was found to provide the highest accuracy on corrected as well as on uncorrected CT data. VMAT is therefore preferable over IMRT for patients with metallic implants, if plan quality is comparable for the two techniques.

Application of TXRF for ion implanter dose matching experiments

NASA Astrophysics Data System (ADS)

Frost, M. R.; French, M.; Harris, W.

2004-06-01

Secondary ion mass spectrometry (SIMS) has been utilized for many years to measure the dose of ion implants in silicon for the purpose of verifying the ability of ion implantation equipment to accurately and reproducibly implant the desired species at the target dose. The development of statistically and instrumentally rigorous protocols has lead to high confidence levels, particularly with regard to accuracy and short-term repeatability. For example, high-dose, high-energy B implant dosimetry can be targeted to within ±1%. However, performing dose determination experiments using SIMS does have undesirable aspects, such as being highly labor intensive and sample destructive. Modern total reflection X-ray fluorescence (TXRF) instruments are equipped with capabilities for full 300 mm wafer handling, automated data acquisition software and intense X-ray sources. These attributes enable the technique to overcome the SIMS disadvantages listed above, as well as provide unique strengths that make it potentially highly amenable to implanter dose matching. In this paper, we report on data collected to date that provides confidence that TXRF is an effective and economical method to perform these measurements within certain limitations. We have investigated a number of ion implanted species that are within the "envelope" of TXRF application. This envelope is defined by a few important parameters. Species: For the anode materials used in the more common X-ray sources on the market, each has its own set of elements that can be detected. We have investigated W and Mo X-ray sources, which are the most common in use in commercial instrumentation. Implant energy: In general, if the energy of the implanted species is too high (or more specifically, the distribution of the implanted species is too deep), the amount of dopant not detected by TXRF may be significant, increasing the error of the measurement. Therefore, for each species investigated, the implant energy cannot exceed a certain level. Dose: Logically, as the implanted dose falls below a certain point, the concentration will be below the TXRF detection limit. In addition to the improved precision of TXRF over SIMS for dose matching, a number of other advantages will be discussed.

Implementation of wireless power transfer and communications for an implantable ocular drug delivery system.

PubMed

Tang, T B; Smith, S; Flynn, B W; Stevenson, J T M; Gundlach, A M; Reekie, H M; Murray, A F; Renshaw, D; Dhillon, B; Ohtori, A; Inoue, Y; Terry, J G; Walton, A J

2008-09-01

A wireless power transfer and communication system based on near-field inductive coupling has been designed and implemented. The feasibility of using such a system to remotely control drug release from an implantable drug delivery system is addressed. The architecture of the wireless system is described and the signal attenuation over distance in both water and phosphate buffered saline is studied. Additionally, the health risk due to exposure to radio frequency (RF) radiation is examined using a biological model. The experimental results demonstrate that the system can trigger the release of drug within 5 s, and that such short exposure to RF radiation does not produce any significant (

Lessons Learned from Autopsying an Unidentified Body with Iodine-125 Seeds Implanted for Prostate Brachytherapy.

PubMed

Idota, Nozomi; Nakamura, Mami; Masui, Koji; Kakiuchi, Yasuhiro; Yamada, Kei; Ikegaya, Hiroshi

2017-03-01

We report here lessons learned from an autopsy case involving radioactive materials. We performed an autopsy of an unidentified mummified man with no available medical history whom from imaging findings we suspected had received radioactive seed implants for prostate brachytherapy. We returned the excised prostate and seeds to the body. A few days later, the body was identified by DNA matching and cremated. According to the man's medical record, he had undergone iodine-125 seeds implantation for prostate cancer 11 months earlier. We should have removed the radioactive seeds from the body to prevent radiation exposure to the bereaved family and/or environmental pollution due to cremation. Surprisingly, one seed was found in the stored prostate specimen. Forensic experts should be cognizant of the risk of both radiation exposure in the autopsy room and environmental pollution. We must remain abreast of the latest advances in medicine. © 2016 American Academy of Forensic Sciences.

Influence of source batch S{sub K} dispersion on dosimetry for prostate cancer treatment with permanent implants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nuñez-Cumplido, E., E-mail: ejnc-mccg@hotmail.com; Hernandez-Armas, J.; Perez-Calatayud, J.

2015-08-15

Purpose: In clinical practice, specific air kerma strength (S{sub K}) value is used in treatment planning system (TPS) permanent brachytherapy implant calculations with {sup 125}I and {sup 103}Pd sources; in fact, commercial TPS provide only one S{sub K} input value for all implanted sources and the certified shipment average is typically used. However, the value for S{sub K} is dispersed: this dispersion is not only due to the manufacturing process and variation between different source batches but also due to the classification of sources into different classes according to their S{sub K} values. The purpose of this work is tomore » examine the impact of S{sub K} dispersion on typical implant parameters that are used to evaluate the dose volume histogram (DVH) for both planning target volume (PTV) and organs at risk (OARs). Methods: The authors have developed a new algorithm to compute dose distributions with different S{sub K} values for each source. Three different prostate volumes (20, 30, and 40 cm{sup 3}) were considered and two typical commercial sources of different radionuclides were used. Using a conventional TPS, clinically accepted calculations were made for {sup 125}I sources; for the palladium, typical implants were simulated. To assess the many different possible S{sub K} values for each source belonging to a class, the authors assigned an S{sub K} value to each source in a randomized process 1000 times for each source and volume. All the dose distributions generated for each set of simulations were assessed through the DVH distributions comparing with dose distributions obtained using a uniform S{sub K} value for all the implanted sources. The authors analyzed several dose coverage (V{sub 100} and D{sub 90}) and overdosage parameters for prostate and PTV and also the limiting and overdosage parameters for OARs, urethra and rectum. Results: The parameters analyzed followed a Gaussian distribution for the entire set of computed dosimetries. PTV and prostate V{sub 100} and D{sub 90} variations ranged between 0.2% and 1.78% for both sources. Variations for the overdosage parameters V{sub 150} and V{sub 200} compared to dose coverage parameters were observed and, in general, variations were larger for parameters related to {sup 125}I sources than {sup 103}Pd sources. For OAR dosimetry, variations with respect to the reference D{sub 0.1cm{sup 3}} were observed for rectum values, ranging from 2% to 3%, compared with urethra values, which ranged from 1% to 2%. Conclusions: Dose coverage for prostate and PTV was practically unaffected by S{sub K} dispersion, as was the maximum dose deposited in the urethra due to the implant technique geometry. However, the authors observed larger variations for the PTV V{sub 150}, rectum V{sub 100}, and rectum D{sub 0.1cm{sup 3}} values. The variations in rectum parameters were caused by the specific location of sources with S{sub K} value that differed from the average in the vicinity. Finally, on comparing the two sources, variations were larger for {sup 125}I than for {sup 103}Pd. This is because for {sup 103}Pd, a greater number of sources were used to obtain a valid dose distribution than for {sup 125}I, resulting in a lower variation for each S{sub K} value for each source (because the variations become averaged out statistically speaking)« less

Maximization of DRAM yield by control of surface charge and particle addition during high dose implantation

NASA Astrophysics Data System (ADS)

Horvath, J.; Moffatt, S.

1991-04-01

Ion implantation processing exposes semiconductor devices to an energetic ion beam in order to deposit dopant ions in shallow layers. In addition to this primary process, foreign materials are deposited as particles and surface films. The deposition of particles is a major cause of IC yield loss and becomes even more significant as device dimensions are decreased. Control of particle addition in a high-volume production environment requires procedures to limit beamline and endstation sources, control of particle transport, cleaning procedures and a well grounded preventative maintenance philosophy. Control of surface charge by optimization of the ion beam and electron shower conditions and measurement with a real-time charge sensor has been effective in improving the yield of NMOS and CMOS DRAMs. Control of surface voltages to a range between 0 and -20 V was correlated with good implant yield with PI9200 implanters for p + and n + source-drain implants.

Survival of Dental Implants Placed in Grafted and Nongrafted Bone: A Retrospective Study in a University Setting.

PubMed

Tran, Duong T; Gay, Isabel C; Diaz-Rodriguez, Janice; Parthasarathy, Kavitha; Weltman, Robin; Friedman, Lawrence

2016-01-01

To compare dental implant survival rates when placed in native bone and grafted sites. Additionally, risk factors associated with dental implant loss were identified. This study was based on the hypothesis that bone grafting has no effect on implant survival rates. A retrospective chart review was conducted for patients receiving dental implants at the University of Texas, School of Dentistry from 1985 to 2012. Exclusion criteria included patients with genetic diseases, radiation and chemotherapy, or an age less than 18 years. To avoid misclassification bias, implants were excluded if bone grafts were only done at the same time of placement. Data on age, sex, tobacco use, diabetes, osteoporosis, anatomical location of the implant, implant length and width, bone graft, and professional maintenance were collected for analysis. A total of 1,222 patients with 2,729 implants were included. The cumulative survival rates at 5 and 10 years were 92% and 87% for implants placed in native bone and 90% and 79% for implants placed in grafted bone, respectively. The results from multivariate analysis (Cox regression) indicated no significant difference in survival between the two groups; having maintenance therapy after implant placement reduced the failure rate by 80% (P < .001), and using tobacco increased the failure rate by 2.6-fold (P = .001). There was no difference in the dental implant survival rate when implants were placed in native bone or bone-grafted sites. Smoking and lack of professional maintenance were significantly related to increased implant loss.

Nitrogen ion implantation into various materials using 28 GHz electron cyclotron resonance ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Chang Seouk; School of Mechanical Engineering, Pusan National University, Pusan 609-735; Lee, Byoung-Seob

2016-02-15

The installation of the 28 GHz electron cyclotron resonance ion source (ECRIS) ion implantation beamline was recently completed at the Korea Basic Science Institute. The apparatus contains a beam monitoring system and a sample holder for the ion implantation process. The new implantation system can function as a multipurpose tool since it can implant a variety of ions, ranging hydrogen to uranium, into different materials with precise control and with implantation areas as large as 1–10 mm{sup 2}. The implantation chamber was designed to measure the beam properties with a diagnostic system as well as to perform ion implantation withmore » an in situ system including a mass spectrometer. This advanced implantation system can be employed in novel applications, including the production of a variety of new materials such as metals, polymers, and ceramics and the irradiation testing and fabrication of structural and functional materials to be used in future nuclear fusion reactors. In this investigation, the first nitrogen ion implantation experiments were conducted using the new system. The 28 GHz ECRIS implanted low-energy, multi-charged nitrogen ions into copper, zinc, and cobalt substrates, and the ion implantation depth profiles were obtained. SRIM 2013 code was used to calculate the profiles under identical conditions, and the experimental and simulation results are presented and compared in this report. The depths and ranges of the ion distributions in the experimental and simulation results agree closely and demonstrate that the new system will enable the treatment of various substrates for advanced materials research.« less

Management of patients with implanted cardiac devices during radiotherapy: results of a Spanish survey in radiation oncology departments.

PubMed

Sabater, S; Montero, A; López Fernández, T; González Ferrer, J J; Arenas, M

2018-05-23

There is an increasing number of patients with cardiac implantable electronic devices (CIED), either pacemakers or defibrillators, who are receiving a course of radiotherapy. Several guidelines have been published by national societies, but no Spanish national guidelines for management of these patients have been published. More importantly, national clinical practice regarding these patients is not standardised. Members of the Spanish Breast Cancer Radiation Oncology Group (GEORM in Spanish) were surveyed through an online questionnaire on behalf of the Spanish radiation oncology departments. Only 39.3% of the Spanish radiation oncology departments have policies aimed at CIED carrier patients. Regardless of that, 96.4% of those who responded to the survey refer these patients to their Cardiology department before the start of the course of radiotherapy, and 17.8% of respondents said to manipulate the CIED without any cardiology department direction. A wide range of responses was obtained related to concepts such as "distance from the irradiation field to the CIED" or "safe accumulated doses". Our results demonstrate the need for national guidelines for CIED patients and the need to promote educational activities addressed to standardise clinical management of these patients in the radiation oncology departments.

Optical and Interface-Based Methods of Defect Engineering in Silicon

ERIC Educational Resources Information Center

Kondratenko, Yevgeniy Vladimirovich

2009-01-01

Ion implantation is widely used in the microelectronics industry for fabrication of source and drain transistor regions. Unfortunately, implantation causes considerable damage to the substrate lattice rendering most of the implanted dopant electrically inactive. Rapid thermal annealing (RTA) heals the damage by rapidly heating the substrate with a…

Assessing the oxidation states and structural stability of the Ce analogue of brannerite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aluri, Esther Rani; Bachiu, Lisa M.; Grosvenor, Andrew P.

2017-07-04

The Ce-containing analogue of brannerite (ie, UTi2O6) was previously considered to be stoichiometric (ie, CeTi2O6); however, it has recently been determined that the material is O deficient. This oxygen-deficient material has been suggested to be charged balanced by the presence of a minor concentration of Ce3+ or by the A-site being cation deficient with the Ce oxidation state being 4+. A variety of Ti-containing oxides (including brannerite) have been investigated as potential nuclear wasteforms, and it is necessary to understand the electronic structure of a proposed nuclear wasteform material as well as how the structure responds to radiation from incorporatedmore » waste elements. The radiation resistance of a material can be simulated by ion implantation. The objective of this study was to confirm the Ce oxidation state in the cation- and oxygen-deficient material (ie, Ce0.94Ti2O6 - δ) and to determine how radiation damage affects this material. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy were used to study Ce0.94Ti2O6 - δ before and after being implanted with 2 MeV Au- ions. Analysis of the Ce 3d XPS spectra from the as-synthesized samples by using a previously developed fitting method has unequivocally shown that Ce adopts both 4+ (major) and 3+ (minor) oxidation states, which was confirmed by examination of magnetic susceptibility data. Analysis of XPS and X-ray absorption near-edge spectroscopy spectra from ion-implanted materials showed that both Ce and Ti were reduced because of radiation damage and that the local coordination environments of the cations are greatly affected by radiation damage.« less

Assessment of thermal effects in a model of the human head implanted with a wireless active microvalve for the treatment of glaucoma creating a filtering bleb.

PubMed

Schaumburg, F; Guarnieri, F A

2017-05-07

A 3D anatomical computational model is developed to assess thermal effects due to exposure to the electromagnetic field required to power a new investigational active implantable microvalve for the treatment of glaucoma. Such a device, located in the temporal superior eye quadrant, produces a filtering bleb, which is included in the geometry of the model, together with the relevant ocular structures. The electromagnetic field source-a planar coil-as well as the microvalve antenna and casing are also included. Exposure to the electromagnetic field source of an implanted and a non-implanted subject are simulated by solving a magnetic potential formulation, using the finite element method. The maximum SAR 10 is reached in the eyebrow and remains within the limits suggested by the IEEE and ICNIRP standards. The anterior chamber, filtering bleb, iris and ciliary body are the ocular structures where more absorption occurs. The temperature rise distribution is also obtained by solving the bioheat equation with the finite element method. The numerical results are compared with the in vivo measurements obtained from four rabbits implanted with the microvalve and exposed to the electromagnetic field source.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ammigan, K.; Hurh, P.

The Radiation Damage In Accelerator Target Environments (RaDIATE) collaboration was founded in 2012 and currently consists of over 50 participants and 11 institutions globally. Due to the increasing power of future proton accelerator sources in target facilities, there is a critical need to further understand the physical and thermo-mechanical radiation response of target facility materials. Thus, the primary objective of the RaDIATE collaboration is to draw on existing expertise in the nuclear materials and accelerator targets fields to generate new and useful materials data for application within the accelerator and fission/fusion communities. Current research activities of the collaboration include postmore » irradiation examination (PIE) of decommissioned components from existing beamlines such as the NuMI beryllium beam window and graphite NT-02 target material. PIE of these components includes advanced microstructural analyses (SEM/TEM, EBSD, EDS) and micro-mechanics technique such as nano-indentation, to help characterize any microstructural radiation damage incurred during operation. New irradiation campaigns of various candidate materials at both low and high energy beam facilities are also being pursued. Beryllium helium implantation studies at the University of Surrey as well as high energy proton irradiation of various materials at Brookhaven National Laboratory’s BLIP facility have been initiated. The program also extends to beam-induced thermal shock experiments using high intensity beam pulses at CERN’s HiRadMat facility, followed by advanced PIE activities to evaluate thermal shock resistance of the materials. Preliminary results from ongoing research activities, as well as the future plans of the RaDIATE collaboration R&D program will be discussed.« less

Electromagnetic transponders indicate prostate size increase followed by decrease during the course of external beam radiation therapy.

PubMed

King, Benjamin L; Butler, Wayne M; Merrick, Gregory S; Kurko, Brian S; Reed, Joshua L; Murray, Brian C; Wallner, Kent E

2011-04-01

Real-time image guidance enables more accurate radiation therapy by tracking target movement. This study used transponder positions to monitor changes in prostate volume that may be a source of dosimetric and target inaccuracy. Twenty-four men with biopsy-proven T1c-T3a prostate cancer each had three electromagnetic transponders implanted transperineally. Their coordinates were recorded by the Calypso system, and the perimeter of the triangle formed by the transponders was used to calculate prostate volumes at sequential time points throughout the course of radiation therapy to a dose of 81 Gy in 1.8-Gy fractions. There was a significant decrease in mean prostate volume of 10.9% from the first to the final day of radiation therapy. The volume loss did not occur monotonically but increased in most patients (75%) during the first several weeks to a median maximum on Day 7. The volume increased by a mean of 6.1% before decreasing by a mean maximum difference of 18.4% to nadir (p < 0.001 for both increase and decrease). Glandular shrinkage was asymmetric, with the apex to right base dimension varying more than twice that of the lateral dimension. For all dimensions, the mean change was <0.5 cm. Real-time transponder positions indicated a volume increase during the initial days of radiation therapy and then significant and asymmetric shrinkage by the final day. Understanding and tracking volume fluctuations of the prostate during radiation therapy can help real-time imaging technology perform to its fullest potential. Copyright © 2011 Elsevier Inc. All rights reserved.

Study of crosslinking onset and hydrogen annealing of ultra-high molecular weight polyethylene irradiated with high-energy protons

NASA Astrophysics Data System (ADS)

Wilson, John Ford

1997-09-01

Ultra high molecular weight polyethylene (UHMW-PE) is used extensively in hip and knee endoprostheses. Radiation damage from the sterilization of these endoprostheses prior to surgical insertion results in polymer crosslinking and decreased oxidative stability. The motivation for this study was to determine if UHMW-PE could be crosslinked by low dose proton irradiation with minimal radiation damage and its subsequent deleterious effects. I found that low dose proton irradiation and post irradiation hydrogen annealing did crosslink UHMW-PE and limit post irradiation oxidation. Crosslinking onset was investigated for UHMW-PE irradiated with 2.6 and 30 MeV H+ ions at low doses from 5.7 × 1011-2.3 × 1014 ions/cm2. Crosslinking was determined from gel permeation chromatography (GPC) of 1,2,4 trichlorobenzene sol fractions and increased with dose. Fourier transform infrared spectroscopy (FTIR) showed irradiation resulted in increased free radicals confirmed from increased carbonyl groups. Radiation damage, especially at the highest doses observed, also showed up in carbon double bonds and increased methyl end groups. Hydrogen annealing after ion irradiation resulted in 40- 50% decrease in FTIR absorption associated with carbonyl. The hydrogen annealing prevented further oxidation after aging for 1024 hours at 80oC. Hydrogen annealing was successful in healing radiation damage through reacting with the free radicals generated during proton irradiation. Polyethylenes, polyesters, and polyamides are used in diverse applications by the medical profession in the treatment of orthopedic impairments and cardiovascular disease and for neural implants. These artificial implants are sterilized with gamma irradiation prior to surgery and the resulting radiation damage can lead to accelerated deterioration of the implant properties. The findings in this study will greatly impact the continued use of these materials through the elimination of many problems associated with radiation damage from sterilization. The higher energy transfer for proton compared to gamma irradiation greatly accelerated the radiation damage. Radiation damage increased linearly with dose over the range of doses examined. These results were consistent with findings from earlier researchers of gamma irradiation of polyethylene.

Cone beam computed tomography radiation dose and image quality assessments.

PubMed

Lofthag-Hansen, Sara

2010-01-01

Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and examinations of impacted lower third molars and retained upper cuspids. It varied between 11-77 microSv. Radiation dose should be evaluated together with image quality. Images of a skull phantom were obtained with both units varying tube voltage, tube current, degree of rotation and FOVs. Seven observers assessed subjective image quality using a six-point rating scale for two diagnostic tasks: periapical diagnosis and implant planning in the posterior part of the jaws. Intra-observer agreement was good and inter-observer agreement moderate. Periapical diagnosis was found to, regardless of jaw, require higher exposure parameters compared to implant planning. Implant planning in the lower jaw required higher exposure parameters compared to upper jaw. Substantial dose reduction could be made without loss of diagnostic information by using a rotation of 180 degrees, in particular implant planning in upper jaw. CBCT with small FOVs was found to be well-suited for periapical diagnosis and implant planning. The CTDI method is not applicable estimating effective dose for these units. Based on DAP values effective dose varied between 11-77 microSv (ICRP 60, 1991) in a retrospectively selected patient material. Adaptation of exposure parameters to diagnostic task can give substantial dose reduction.

Structural Transformations in Austenitic Stainless Steel Induced by Deuterium Implantation: Irradiation at 295 K.

PubMed

Morozov, Oleksandr; Zhurba, Volodymir; Neklyudov, Ivan; Mats, Oleksandr; Progolaieva, Viktoria; Boshko, Valerian

2016-12-01

Deuterium thermal desorption spectra were investigated on the samples of austenitic steel 18Cr10NiTi pre-implanted at 295 K with deuterium ions in the dose range from 8 × 10(14) to 2.7 × 10(18) D/cm(2). The kinetics of structural transformation development in the steel layer was traced from deuterium thermodesorption spectra as a function of deuterium concentration. Three characteristic regions with different low rates of deuterium amount desorption as the implantation dose increases were revealed: I-the linear region of low implantation doses (up to 1 × 10(17) D/cm(2)); II-the nonlinear region of medium implantation doses (1 × 10(17) to 8 × 10(17) D/cm(2)); III-the linear region of high implantation doses (8 × 10(17) to 2.7 × 10(18) D/cm(2)). During the process of deuterium ion irradiation, the coefficient of deuterium retention in steel varies in discrete steps. Each of the discrete regions of deuterium retention coefficient variation corresponds to different implanted-matter states formed during deuterium ion implantation. The low-dose region is characterized by formation of deuterium-vacancy complexes and solid-solution phase state of deuterium in the steel. The total concentration of the accumulated deuterium in this region varies between 2.5 and 3 at.%. The medium-dose region is characterized by the radiation-induced action on the steel in the presence of deuterium with the resulting formation of the energy-stable nanosized crystalline structure of steel, having a developed network of intercrystalline boundaries. The basis for this developed network of intercrystalline boundaries is provided by the amorphous state, which manifests itself in the thermodesorption spectra as a widely temperature-scale extended region of deuterium desorption (structure formation with a varying activation energy). The total concentration of the accumulated deuterium in the region of medium implantation doses makes 7 to 8 at.%. The resulting structure shows stability against the action of deuterium ion implantation. This manifests itself in a nearly complete ceasing of deuterium accumulation from a newly implanted dose (radiation-resistant structure).

Evaluation of a head-repositioner and Z-plate system for improved accuracy of dose delivery.

PubMed

Charney, Sarah C; Lutz, Wendell R; Klein, Mary K; Jones, Pamela D

2009-01-01

Radiation therapy requires accurate dose delivery to targets often identifiable only on computed tomography (CT) images. Translation between the isocenter localized on CT and laser setup for radiation treatment, and interfractional head repositioning are frequent sources of positioning error. The objective was to design a simple, accurate apparatus to eliminate these sources of error. System accuracy was confirmed with phantom and in vivo measurements. A head repositioner that fixates the maxilla via dental mold with fiducial marker Z-plates attached was fabricated to facilitate the connection between the isocenter on CT and laser treatment setup. A phantom study targeting steel balls randomly located within the head repositioner was performed. The center of each ball was marked on a transverse CT slice on which six points of the Z-plate were also visible. Based on the relative position of the six Z-plate points and the ball center, the laser setup position on each Z-plate and a top plate was calculated. Based on these setup marks, orthogonal port films, directed toward each target, were evaluated for accuracy without regard to visual setup. A similar procedure was followed to confirm accuracy of in vivo treatment setups in four dogs using implanted gold seeds. Sequential port films of three dogs were made to confirm interfractional accuracy. Phantom and in vivo measurements confirmed accuracy of 2 mm between isocenter on CT and the center of the treatment dose distribution. Port films confirmed similar accuracy for interfractional treatments. The system reliably connects CT target localization to accurate initial and interfractional radiation treatment setup.

Sources of Variability in Language Development of Children with Cochlear Implants: Age at Implantation, Parental Language, and Early Features of Children's Language Construction

ERIC Educational Resources Information Center

Szagun, Gisela; Schramm, Satyam A.

2016-01-01

The aim of the present study was to analyze the relative influence of age at implantation, parental expansions, and child language internal factors on grammatical progress in children with cochlear implants (CI). Data analyses used two longitudinal corpora of spontaneous speech samples, one with twenty-two and one with twenty-six children,…

Infrared Radiography: Modeling X-ray Imaging without Harmful Radiation

ERIC Educational Resources Information Center

Zietz, Otto; Mylott, Elliot; Widenhorn, Ralf

2015-01-01

Planar x-ray imaging is a ubiquitous diagnostic tool and is routinely performed to diagnose conditions as varied as bone fractures and pneumonia. The underlying principle is that the varying attenuation coefficients of air, water, tissue, bone, or metal implants within the body result in non-uniform transmission of x-ray radiation. Through the…

Cone beam computed tomography in implant dentistry: a systematic review focusing on guidelines, indications, and radiation dose risks.

PubMed

Bornstein, Michael M; Scarfe, William C; Vaughn, Vida M; Jacobs, Reinhilde

2014-01-01

The aim of the paper is to identify, review, analyze, and summarize available evidence in three areas on the use of cross-sectional imaging, specifically maxillofacial cone beam computed tomography (CBCT) in pre- and postoperative dental implant therapy: (1) Available clinical use guidelines, (2) indications and contraindications for use, and (3) assessment of associated radiation dose risk. Three focused questions were developed to address the aims. A systematic literature review was performed using a PICO-based search strategy based on MeSH key words specific to each focused question of English-language publications indexed in the MEDLINE database retrospectively from October 31, 2012. These results were supplemented by a hand search and gray literature search. Twelve publications were identified providing guidelines for the use of cross-sectional radiography, particularly CBCT imaging, for the pre- and/or postoperative assessment of potential dental implant sites. The publications discovered by the PICO strategy (43 articles), hand (12), and gray literature searches (1) for the second focus question regarding indications and contraindications for CBCT use in implant dentistry were either cohort or case-controlled studies. For the third question on the assessment of associated radiation dose risk, a total of 22 articles were included. Publication characteristics and themes were summarized in tabular format. The reported indications for CBCT use in implant dentistry vary from preoperative analysis regarding specific anatomic considerations, site development using grafts, and computer-assisted treatment planning to postoperative evaluation focusing on complications due to damage of neurovascular structures. Effective doses for different CBCT devices exhibit a wide range with the lowest dose being almost 100 times less than the highest dose. Significant dose reduction can be achieved by adjusting operating parameters, including exposure factors and reducing the field of view (FOV) to the actual region of interest.

SU-E-I-42: Normalized Embryo/fetus Doses for Fluoroscopically Guided Pacemaker Implantation Procedures Calculated Using a Monte Carlo Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Damilakis, J; Stratakis, J; Solomou, G

Purpose: It is well known that pacemaker implantation is sometimes needed in pregnant patients with symptomatic bradycardia. To our knowledge, there is no reported experience regarding radiation doses to the unborn child resulting from fluoroscopy during pacemaker implantation. The purpose of the current study was to develop a method for estimating embryo/fetus dose from fluoroscopically guided pacemaker implantation procedures performed on pregnant patients during all trimesters of gestation. Methods: The Monte Carlo N-Particle (MCNP) radiation transport code was employed in this study. Three mathematical anthropomorphic phantoms representing the average pregnant patient at the first, second and third trimesters of gestationmore » were generated using Bodybuilder software (White Rock science, White Rock, NM). The normalized embryo/fetus dose from the posteroanterior (PA), the 30° left-anterior oblique (LAO) and the 30° right-anterior oblique (RAO) projections were calculated for a wide range of kVp (50–120 kVp) and total filtration values (2.5–9.0 mm Al). Results: The results consist of radiation doses normalized to a) entrance skin dose (ESD) and b) dose area product (DAP) so that the dose to the unborn child from any fluoroscopic technique and x-ray device used can be calculated. ESD normalized doses ranged from 0.008 (PA, first trimester) to 2.519 μGy/mGy (RAO, third trimester). DAP normalized doses ranged from 0.051 (PA, first trimester) to 12.852 μGy/Gycm2 (RAO, third trimester). Conclusion: Embryo/fetus doses from fluoroscopically guided pacemaker implantation procedures performed on pregnant patients during all stages of gestation can be estimated using the method developed in this study. This study was supported by the Greek Ministry of Education and Religious Affairs, General Secretariat for Research and Technology, Operational Program ‘Education and Lifelong Learning’, ARISTIA (Research project: CONCERT)« less

Noise reduction technologies implemented in head-worn preprocessors for improving cochlear implant performance in reverberant noise fields.

PubMed

Chung, King; Nelson, Lance; Teske, Melissa

2012-09-01

The purpose of this study was to investigate whether a multichannel adaptive directional microphone and a modulation-based noise reduction algorithm could enhance cochlear implant performance in reverberant noise fields. A hearing aid was modified to output electrical signals (ePreprocessor) and a cochlear implant speech processor was modified to receive electrical signals (eProcessor). The ePreprocessor was programmed to flat frequency response and linear amplification. Cochlear implant listeners wore the ePreprocessor-eProcessor system in three reverberant noise fields: 1) one noise source with variable locations; 2) three noise sources with variable locations; and 3) eight evenly spaced noise sources from 0° to 360°. Listeners' speech recognition scores were tested when the ePreprocessor was programmed to omnidirectional microphone (OMNI), omnidirectional microphone plus noise reduction algorithm (OMNI + NR), and adaptive directional microphone plus noise reduction algorithm (ADM + NR). They were also tested with their own cochlear implant speech processor (CI_OMNI) in the three noise fields. Additionally, listeners rated overall sound quality preferences on recordings made in the noise fields. Results indicated that ADM+NR produced the highest speech recognition scores and the most preferable rating in all noise fields. Factors requiring attention in the hearing aid-cochlear implant integration process are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Magnetic resonance imaging-a diagnostic tool for postoperative evaluation of dental implants: a case report.

PubMed

Wanner, Laura; Ludwig, Ute; Hövener, Jan-Bernd; Nelson, Katja; Flügge, Tabea

2018-04-01

Compared with cone beam computed tomography (CBCT), magnetic resonance imaging (MRI) might be superior for the diagnosis of nerve lesions associated with implant placement. A patient presented with unilateral pain associated with dysesthesia in the region of the right lower lip and chin after implant placement. Conventional orthopantomography could not identify an association between the position of the inferior alveolar nerve and the implant. For 3-dimensional display of the implant in relation to the surrounding anatomy, CBCT was compared with MRI. MRI enabled the precise depiction of the implant position and its spatial relation to the inferior alveolar nerve, whereas the nerve position and its exact course within the mandible could not be directly displayed in CBCT. MRI may be a valuable, radiation-free diagnostic tool for the visualization of intraoral hard and soft tissues, offering an objective assessment of nerve injuries by a direct visualization of the inferior alveolar neurovascular bundle. Copyright © 2018 Elsevier Inc. All rights reserved.

Ion implantation of highly corrosive electrolyte battery components

DOEpatents

Muller, R.H.; Zhang, S.

1997-01-14

A method of producing corrosion resistant electrodes and other surfaces in corrosive batteries using ion implantation is described. Solid electrically conductive material is used as the ion implantation source. Battery electrode grids, especially anode grids, can be produced with greatly increased corrosion resistance for use in lead acid, molten salt, and sodium sulfur. 6 figs.

Ion implantation of highly corrosive electrolyte battery components

DOEpatents

Muller, Rolf H.; Zhang, Shengtao

1997-01-01

A method of producing corrosion resistant electrodes and other surfaces in corrosive batteries using ion implantation is described. Solid electrically conductive material is used as the ion implantation source. Battery electrode grids, especially anode grids, can be produced with greatly increased corrosion resistance for use in lead acid, molten salt, end sodium sulfur.

USAF Summer Faculty Research Program. 1980. Research Reports. Volume II.

DTIC Science & Technology

1980-10-01

Radiation Damage Profiles and Annealing Dr. Samuel C. Ling Effects of 120 keV Sulfur Implants in GaAs 45 Finite Element Modeling of Elastic-Plastic Dr...described more fully in a later section. II. OBJECTIVES: Laboratory management is acutely aware of the shortcomings of the current informational processes...are fixed, there are only two modes of heat trans- fer - radiation and conduction. At the low temperatures necessary for superconductivity, radiation

Transplantation of rib cartilage reshaped with 1.56 μm laser radiation in rabbits

NASA Astrophysics Data System (ADS)

Sobol, E.; Baum, O.; Alexandrovskaya, Yu.; Shekhter, A.; Selezneva, L.; Svistuskin, V.

2017-02-01

As cartilage is an ideal natural material for transplantation, its use in the ENT surgery is limited by a difficulty to get proper shape of cartilage implants. Aim of the work is to make ring-shaped cartilage implants, to check their stability after laser reshaping and to perform transplantation into rabbits in vivo. We experimented with costal cartilages of 1-2 mm in thickness obtained from 3rd and 4rd ribs of a rabbit. 1.56 μm laser (Arcuo Medical Inc.) was used for cartilage reshaping. The laser settings were established taking into account anisotropy of cartilage structure for different orientation of the implants. The reshaped cartilage implants were surgically sewn to rib cartilages of the other rabbits. The rabbits were slaughtered in 3.5-4 months after surgery. The results have shown that (1) all reshaped implants kept circular form, and (2) the implants were adhered to the native rabbit cartilage sites (3) pronounced signs of regeneration in the intermediate zones were observed. The prospects of the cartilage implants use in larynx stenosis surgery are discussed.

Reconstruction of irradiated bone segmental defects with a biomaterial associating MBCP+(R), microstructured collagen membrane and total bone marrow grafting: an experimental study in rabbits.

PubMed

Jégoux, Franck; Goyenvalle, Eric; Cognet, Ronan; Malard, Olivier; Moreau, Francoise; Daculsi, Guy; Aguado, Eric

2009-12-15

The bone tissue engineering models used today are still a long way from any oncologic application as immediate postimplantation irradiation would decrease their osteoinductive potential. The aim of this study was to reconstruct a segmental critical size defect in a weight-bearing bone irradiated after implantation. Six white New Zealand rabbits were immediately implanted with a biomaterial associating resorbable collagen membrane EZ(R) filled and micro-macroporous biphasic calcium phosphate granules (MBCP+(R)). After a daily schedule of radiation delivery, and within 4 weeks, a total autologous bone marrow (BM) graft was injected percutaneously into the center of the implant. All the animals were sacrificed at 16 weeks. Successful osseous colonization was found to have bridged the entire length of the defects. Identical distribution of bone ingrowth and residual ceramics at the different levels of the implant suggests that the BM graft plays an osteoinductive role in the center of the defect. Periosteum-like formation was observed at the periphery, with the collagen membrane most likely playing a role. This model succeeded in bridging a large segmental defect in weight-bearing bone with immediate postimplantation fractionated radiation delivery. This has significant implications for the bone tissue engineering approach to patients with cancer-related bone defects.

RBS-channeling study of radiation damage in Ar{sup +} implanted CuInSe{sub 2} crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yakushev, Michael V., E-mail: michael.yakushev@strath.ac.uk; Ural Federal University, Ekaterinburg 620002; Institute of Solid State Chemistry of the Urals Branch of RAS, Ekaterinburg 620990

2016-09-15

Chalcopyrite solar cells are reported to have a high tolerance to irradiation by high energy electrons or ions, but the origin of this is not well understood. This work studies the evolution of damage in Ar{sup +}-bombarded CuInSe{sub 2} single crystal using Rutherford backscattering/channeling analysis. Ar{sup +} ions of 30 keV were implanted with doses in the range from 10{sup 12} to 3 × 10{sup 16} cm{sup −2} at room temperature. Implantation was found to create two layers of damage: (1) on the surface, caused by preferential sputtering of Se and Cu atoms; (2) at the layer of implanted Ar, possibly consisting of stackingmore » faults and dislocation loops. The damage in the second layer was estimated to be less than 2% of the theoretical prediction suggesting efficient healing of primary implantation defects.« less

Breast Implant-Associated Anaplastic Large Cell Lymphoma: Case Report and Review of the Literature.

PubMed

Berlin, Eva; Singh, Kunwar; Mills, Christopher; Shapira, Ilan; Bakst, Richard L; Chadha, Manjeet

2018-01-01

We are reporting the case of a 58-year-old woman with history of bilateral silicone breast implants for cosmetic augmentation. At 2-year interval from receiving the breast implants, she presented with swelling of the right breast with associated chest wall mass, effusion around the implant, and axillary lymphadenopathy. Pathology confirmed breast implant-associated anaplastic large cell lymphoma (stage III, T4N2M0, using BIA-ALCL TNM staging and stage IIAE, using Ann-Arbor staging). The patient underwent bilateral capsulectomy and right partial mastectomy with excision of the right breast mass and received adjuvant CHOP chemotherapy and radiation to the right breast and regional nodes. Since completion of multimodality therapy, the patient has sustained remission on both clinical exam and PET/CT scan. We report this case and review of the literature on this rare form of lymphoma.

Breast Implant-Associated Anaplastic Large Cell Lymphoma: Case Report and Review of the Literature

PubMed Central

Singh, Kunwar; Mills, Christopher; Shapira, Ilan

2018-01-01

We are reporting the case of a 58-year-old woman with history of bilateral silicone breast implants for cosmetic augmentation. At 2-year interval from receiving the breast implants, she presented with swelling of the right breast with associated chest wall mass, effusion around the implant, and axillary lymphadenopathy. Pathology confirmed breast implant-associated anaplastic large cell lymphoma (stage III, T4N2M0, using BIA-ALCL TNM staging and stage IIAE, using Ann-Arbor staging). The patient underwent bilateral capsulectomy and right partial mastectomy with excision of the right breast mass and received adjuvant CHOP chemotherapy and radiation to the right breast and regional nodes. Since completion of multimodality therapy, the patient has sustained remission on both clinical exam and PET/CT scan. We report this case and review of the literature on this rare form of lymphoma. PMID:29607225

High-temperature Au implantation into Ni-Be and Ni-Si alloys

NASA Astrophysics Data System (ADS)

James, M. R.; Lam, N. Q.; Rehn, L. E.; Baldo, P. M.; Funk, L.; Stubbins, J. F.

1992-12-01

Effects of implantation temperature and target composition on depth distribution of implanted species were investigated. Au+ ions were implanted at 300 keV into polycrystalline Ni-Be and Ni-Si alloys between 25 and 700C to a dose of 10(exp 16) cm(exp -2). Depth distributions of Au were analyzed with RBS using He+ at both 1.7 and 3.0 MeV, and those of the other alloying elements by SIMS. Theoretical modeling of compositional redistribution during implantation at elevated temperatures was also carried out with the aid of a comprehensive kinetic model. The analysis indicated that below approximately 250C, the primary controlling processes were preferential sputtering and displacement mixing, while between 250 and 600C radiation-induced segregation was dominant. Above 600C, thermal-diffusion effects were most important. Fitting of model calculations to experimental measurements provided values for various defect migration and formation parameters.

Concept Developed for an Implanted Stimulated Muscle-Powered Piezoelectric Generator

NASA Technical Reports Server (NTRS)

Lewandowski, Beth; Kilgore, Kevin; Ercegovic, David; Gustafson, Kenneth

2005-01-01

Implanted electronic devices are typically powered by batteries or transcutaneous power transmission. Batteries must be replaced or recharged, and transcutaneous power sources burden the patient or subject with external equipment prone to failure. A completely self-sustaining implanted power source would alleviate these limitations. Skeletal muscle provides an available autologous power source containing native chemical energy that produces power in excess of the requirements for muscle activation by motor nerve stimulation. A concept has been developed to convert stimulated skeletal muscle power into electrical energy (see the preceding illustration). We propose to connect a piezoelectric generator between a muscle tendon and bone. Electrically stimulated muscle contractions would exert force on the piezoelectric generator, charging a storage circuit that would be used to power the stimulator and other devices.

Evaluation of electron beam stabilization for ion implant processing

NASA Astrophysics Data System (ADS)

Buffat, Stephen J.; Kickel, Bee; Philipps, B.; Adams, J.; Ross, Matthew F.; Minter, Jason P.; Marlowe, Trey; Wong, Selmer S.

1999-06-01

With the integration of high energy ion implant processes into volume CMOS manufacturing, the need for thick resist stabilization to achieve a stable ion implant process is critical. With new photoresist characteristics, new implant end station characteristics arise. The resist outgassing needs to be addressed as well as the implant profile to ensure that the dosage is correct and the implant angle does not interfere with other underlying features. This study compares conventional deep-UV/thermal with electron beam stabilization. The electron beam system used in this study utilizes a flood electron source and is a non-thermal process. These stabilization techniques are applied to a MeV ion implant process in a CMOS production process flow.

Perineal template techniques for interstitial implantation of gynecological cancers using the Paris system of dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leung, S.

1990-09-01

Since 1984, perineal template/needle techniques for interstitial implantation of gynecologic cancer-cervix, vagina, vulva-have been developed at the Peter MacCallum Cancer Institute. The Paris System of dosimetry has been used resulting in greater dose homogeneity, fewer needles and radioactive sources and considerable simplification and ease of implantation compared with comparable techniques developed in the United States. Principles and techniques of implantation are described in detail.

Implanted Miniaturized Antenna for Brain Computer Interface Applications: Analysis and Design

PubMed Central

Zhao, Yujuan; Rennaker, Robert L.; Hutchens, Chris; Ibrahim, Tamer S.

2014-01-01

Implantable Brain Computer Interfaces (BCIs) are designed to provide real-time control signals for prosthetic devices, study brain function, and/or restore sensory information lost as a result of injury or disease. Using Radio Frequency (RF) to wirelessly power a BCI could widely extend the number of applications and increase chronic in-vivo viability. However, due to the limited size and the electromagnetic loss of human brain tissues, implanted miniaturized antennas suffer low radiation efficiency. This work presents simulations, analysis and designs of implanted antennas for a wireless implantable RF-powered brain computer interface application. The results show that thin (on the order of 100 micrometers thickness) biocompatible insulating layers can significantly impact the antenna performance. The proper selection of the dielectric properties of the biocompatible insulating layers and the implantation position inside human brain tissues can facilitate efficient RF power reception by the implanted antenna. While the results show that the effects of the human head shape on implanted antenna performance is somewhat negligible, the constitutive properties of the brain tissues surrounding the implanted antenna can significantly impact the electrical characteristics (input impedance, and operational frequency) of the implanted antenna. Three miniaturized antenna designs are simulated and demonstrate that maximum RF power of up to 1.8 milli-Watts can be received at 2 GHz when the antenna implanted around the dura, without violating the Specific Absorption Rate (SAR) limits. PMID:25079941

Recharging processes, radiation induced strain and changes of OH - bands under H + ion implantation in Ti doped lithium niobate

NASA Astrophysics Data System (ADS)

Kumar, P.; Moorthy Babu, S.; Bhaumik, I.; Ganesamoorthy, S.; Karnal, A. K.; Kumar, Praveen; Rodrigues, G. O.; Sulania, I.; Kanjilal, D.; Pandey, A. K.; Raman, R.

2010-01-01

A systematic analysis of variations in structural and optical characteristics of Z-cut plates of titanium doped congruent lithium niobate single crystals implanted with 120 keV proton beam at various fluences of 10 15, 10 16 and 10 17 protons/cm 2 is presented. Through, high resolution X-ray diffraction, atomic force microscopy, Fourier transform infrared and UV-visible-NIR analysis of congruent lithium niobate, the correlation of properties before and after implantation are discussed. HRXRD (0 0 6) reflection by Triple Crystal Mode shows that both tensile and compressive strain peak are produced by the high fluence implantation. A distinct tensile peak was observed from implanted region for a fluence of 10 16 protons/cm 2. AFM micrographs indicate mountain ridges, bumps and protrusions on target surface on implantation. UV-visible-NIR spectra reveal an increase in charge transfer between Ti 3+/Ti 4+ and ligand oxygen for implantation with 10 15 protons/cm 2, while spectra for higher fluence implanted samples show complex absorption band in the region from 380-1100 nm. Variations of OH - stretching vibration mode were observed for cLN Pure, cLNT2% virgin, and implanted samples with FTIR spectra. The concentration of OH - ion before and after implantation was calculated from integral absorption intensity. The effect of 120 keV proton implantation induced structural, surface and optical studies were correlated.

Novel Technique for Hepatic Fiducial Marker Placement for Stereotactic Body Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarraya, Hajer, E-mail: h-jarraya@o-lambret.fr; Chalayer, Chloé; Tresch, Emmanuelle

2014-09-01

Purpose: To report experience with fiducial marker insertion and describe an advantageous, novel technique for fiducial placement in the liver for stereotactic body radiation therapy with respiratory tracking. Methods and Materials: We implanted 1444 fiducials (single: 834; linked: 610) in 328 patients with 424 hepatic lesions. Two methods of implantation were compared: the standard method (631 single fiducials) performed on 153 patients from May 2007 to May 2010, and the cube method (813 fiducials: 610 linked/203 single) applied to 175 patients from April 2010 to March 2013. The standard method involved implanting a single marker at a time. The novel techniquemore » entailed implanting 2 pairs of linked markers when possible in a way to occupy the perpendicular edges of a cube containing the tumor inside. Results: Mean duration of the cube method was shorter than the standard method (46 vs 61 minutes; P<.0001). Median numbers of skin and subcapsular entries were significantly smaller with the cube method (2 vs 4, P<.0001, and 2 vs 4, P<.0001, respectively). The rate of overall complications (total, major, and minor) was significantly lower in the cube method group compared with the standard method group (5.7% vs 13.7%; P=.013). Major complications occurred while using single markers only. The success rate was 98.9% for the cube method and 99.3% for the standard method. Conclusions: We propose a new technique of hepatic fiducial implantation that makes use of linked fiducials and involves fewer skin entries and shorter time of implantation. The technique is less complication-prone and is migration-resistant.« less

[Virtual Planning of Prosthetic Treatment of the Orbit].

PubMed

Veit, Johannes A; Thierauf, Julia; Egner, Kornelius; Wiggenhauser, Paul Severin; Friedrich, Daniel; Greve, Jens; Schuler, Patrick J; Hoffmann, Thomas K; Schramm, Alexander

2017-06-01

Optimal positioning of bone-anchored implants in the treatment of patients with orbital prosthesis is challenging. The definition of implant axis as well as the positioning of the implants is important to prevent failures in prosthetic rehabilitation in these patients. We performed virtual planning of enossal implants at a base of a standard fan beam CT scan using the software CoDiagnostiX™ (DentalWings, Montréal, Canada). By 3D-printing a surgical guide for drilling and implant insertion was manufactured (Med-610™, Stratasys, Rehovot, Israel). An orbital exenteration was performed in a patient after shrinkage of the eyelids 20 years after enucleation and radiation of the orbit due to rhabdomyosarcoma. 4 Vistafix-3 implants (Cochlear™, Cochlea, Centennial, USA) were primarily inserted after resection with the help of the 3D-surgical guide. Prosthetic rehabilitation could be achieved as preplanned to a predictable result. The individual prosthesis of the orbit showed good functional and esthetic outcome. The virtual 3D-planning of endosseous implants for prosthetic orbital and periorbital reconstruction is easy to use and facilitates optimal placement of implants especially in posttherapeutically altered anatomic situations. © Georg Thieme Verlag KG Stuttgart · New York.

Illumination system having a plurality of movable sources

DOEpatents

Sweatt, William C.; Kubiak, Glenn D.

2002-01-01

An illumination system includes several discharge sources that are multiplexed together to reduce the amount of debris generated. The system includes: (a) a first electromagnetic radiation source array that includes a plurality of first activatable radiation source elements that are positioned on a first movable carriage; (b) a second electromagnetic radiation source array that includes a plurality of second activatable radiation source elements that are positioned on a second movable carriage; (c) means for directing electromagnetic radiation from the first electromagnetic radiation source array and electromagnetic radiation from the second electromagnetic radiation source array toward a common optical path; (d) means for synchronizing (i) the movements of the first movable carriage and of the second movable carriage and (ii) the activation of the first electromagnetic radiation source array and of the second electromagnetic radiation source array to provide an essentially continuous illumination of electromagnetic radiation along the common optical path.

Reporting of sources of funding in systematic reviews in periodontology and implant dentistry.

PubMed

Faggion, C M; Atieh, M; Zanicotti, D G

2014-02-01

Industry-supported clinical trials may present better outcomes than those supported by other sources. The aim of this paper was to assess whether systematic reviews (SRs) published in periodontology and implant dentistry report and discuss the influence of funding sources on study results. Two reviewers conducted a comprehensive search in PubMed and the Cochrane Database of Systematic Reviews independently and in duplicate to identify SRs published up to 11 November 2012. Speciality dental journals and the reference lists of included SRs were also scrutinised. Information on the reporting and discussion of funding sources of primary studies included in the SRs was extracted independently and in duplicate. Any disagreement regarding SR selection or data extraction was discussed until consensus was achieved. Of 146 SRs included in the assessment, only 45 (31%) reported the funding sources of primary studies. Fourteen (10%) SRs discussed the potential influence of funding sources on study results, that is, sponsorship bias. Funding sources are inadequately reported and discussed in SRs in periodontology and implant dentistry. Assessment, reporting, and critical appraisal of potential sponsorship bias of meta-analytic estimates are paramount to provide proper guidance for clinical treatments.

Effect of radiation therapy on permanent pacemaker and implantable cardioverter-defibrillator function.

PubMed

Makkar, Akash; Prisciandaro, Joann; Agarwal, Sunil; Lusk, Morgan; Horwood, Laura; Moran, Jean; Fox, Colleen; Hayman, James A; Ghanbari, Hamid; Roberts, Brett; Belardi, Diego; Latchamsetty, Rakesh; Crawford, Thomas; Good, Eric; Jongnarangsin, Krit; Bogun, Frank; Chugh, Aman; Oral, Hakan; Morady, Fred; Pelosi, Frank

2012-12-01

Radiation therapy's (RT's) effects on cardiac implantable electronic devices (CIEDs) such as implantable cardioverter-defibrillators (ICDs) and pacemakers (PMs) are not well established, leading to device removal or relocation in preparation for RT. To determine the effect of scattered RT on CIED performance. We analyzed 69 patients--50 (72%) with PMs and 19 (28%) with ICDs--receiving RT at the University of Michigan. Collected data included device model, anatomic location, and treatment beam energies, treatment type, and estimated dose to the device. Patients were treated with either high-energy (16-MV) and/or low-energy (6 MV) photon beams with or without electron beams (6-16 MeV). The devices were interrogated with pre- and post-RT and/or weekly with either in-treatment or home interrogation, depending on the patient's dependence on the device and the estimated or measured delivered dose. Outcomes analyzed were inappropriate ICD therapies, device malfunctions, or device-related clinical events. The PMs were exposed to 84.4 ± 99.7 cGy of radiation, and the ICDs were exposed to 92.1 ± 72.6 cGy of radiation. Two patients with ICDs experienced a partial reset of the ICD with the loss of historic diagnostic data after receiving 123 and 4 cGy, respectively. No device malfunction or premature battery depletion was observed at 6-month follow-up from RT completion. CIED malfunction due to indirect RT exposure is uncommon. Regular in-treatment or home interrogation should be done to detect and treat these events and to ensure that diagnostic data are preserved. Copyright © 2012 Elsevier Inc. All rights reserved.

Indirect detection of radiation sources through direct detection of radiolysis products

DOEpatents

Farmer, Joseph C [Tracy, CA; Fischer, Larry E [Los Gatos, CA; Felter, Thomas E [Livermore, CA

2010-04-20

A system for indirectly detecting a radiation source by directly detecting radiolytic products. The radiation source emits radiation and the radiation produces the radiolytic products. A fluid is positioned to receive the radiation from the radiation source. When the fluid is irradiated, radiolytic products are produced. By directly detecting the radiolytic products, the radiation source is detected.

A novel imaging approach for prostate cancer is tested in new clinical trial | Center for Cancer Research

Cancer.gov

Prostate cancer patients who have failed standard radiation therapy have the options of surgery, radioactive seed implantation or cryoablation. Deborah Citrin, M.D., of the Radiation Oncology Branch is leading a study of stereotactic body radiation therapy (SBRT) to treat prostate cancer that has recurred locally after standard radiation therapy. The goal of this study is to use a novel imaging approach to guide treatment and to define the best dose of SBRT for patients whose prostate cancer has recurred after standard radiotherapy. Read more...

Quality assurance of HDR prostate plans: program implementation at a community hospital.

PubMed

Rush, Jennifer B; Thomas, Michael D

2005-01-01

Adenocarcinoma of the prostate is currently the most commonly diagnosed cancer in men in the United States, and the second leading cause of cancer mortality. The utilization of radiation therapy is regarded as the definitive local therapy of choice for intermediate- and high-risk disease, in which there is increased risk for extracapsular extension, seminal vesicle invasion, or regional node involvement. High-dose-rate (HDR) brachytherapy is a logical treatment modality to deliver the boost dose to an external beam radiation therapy (EBRT) treatment to increase local control rates. From a treatment perspective, the utilization of a complicated treatment delivery system, the compressed time frame in which the procedure is performed, and the small number of large dose fractions make the implementation of a comprehensive quality assurance (QA) program imperative. One aspect of this program is the QA of the HDR treatment plan. Review of regulatory and medical physics professional publications shows that substantial general guidance is available. We provide some insight to the implementation of an HDR prostate plan program at a community hospital. One aspect addressed is the utilization of the low-dose-rate (LDR) planning system and the use of existing ultrasound image sets to familiarize the radiation therapy team with respect to acceptable HDR implant geometries. Additionally, the use of the LDR treatment planning system provided a means to prospectively determine the relationship between the treated isodose volume and the product of activity and time for the department's planning protocol prior to the first HDR implant. For the first 12 HDR prostate implants, the root-mean-square (RMS) deviation was 3.05% between the predicted product of activity and time vs. the actual plan values. Retrospective re-evaluation of the actual implant data reduced the RMS deviation to 2.36%.

Total dose radiation test methodologies for advanced spacecraft electronics experiencing enhanced low dose rate sensitivity

NASA Astrophysics Data System (ADS)

Ashton, Chris

The purpose of this thesis is to determine whether hydrogen can be implanted into elec- tronic components for the goal of investigating low ionising dose rate sensitivity, and using this to suggest whether hydrogen implantation can be used as an accelerated method to detect ELDRS (Enhanced Low Dose Rate Sensitivity) susceptability. Current ground testing methods for total ionising dose irradiate using cobalt-60 at dose rates greater than 10mGy(Si)/s up to 200Gy. It has been found that bipolar devices show an increased susceptibility to radiation induced damage at dose rates below 10mGy(Si)/s known as ELDRS. Current research has linked ELDRS susceptibility with hydrogen content within the integrated circuit and experiments based upon hydrogen soaking de-lidded bipolar devices demonstrate this relationship, however this has not led to an accepted method for testing ELDRS susceptibility in previously un-tested devices. In this thesis, a novel proposal is put forward whereby bipolar devices are directly implanted with hydrogen using a targeted ion beam in order to accelerate the testing process. Hydrogen implantation via a 600keV ion beam has been achieved to a level of 10. 17 H/cm. 2 in Analog Device’s AD590KF temperature transducer, and 10. 14-15 H/cm. 2in National Semiconductor’s LM124 quad operational amplifiers. Devices were decapped, optically analysed, and targeted with a focussed proton beam. These devices were then irradiated at 15mGy/s, 5mGy/s and 15mGy/s. Increased degradation was seen at lower dose rates which was matched by high dose rate irradiation of the implanted devices followed by a room temperature anneal. The use of ion implantation for the development of an accelerated ELDRS test method is proposed. This thesis demonstrated that hydrogen can be succesfully implanted into devices, established an upper bound for the LM124 for implantation and a lower bound for hydrogen remaining in the target area and the effect of hydrogen implantation on the AD590 temperature transducer is discussed. This thesis concludes by suggesting hydrogen implantation as a method for use by manufacturers during the design and investigation of intrinsically ELDRS-free technologies.

Anticipating and addressing workplace static magnetic field effects at levels <0.5 mT.

PubMed

Emery, R J; Hopkins, J R; Charlton, M A

2000-11-01

Magnetic resonance, once a research tool limited to the basic sciences, has experienced an increase in popularity due to its unique ability to analyze certain living systems in vivo. Expanding applications in the biomedical sciences have resulted in magnetic sources being located in research institutions nationally. Space and resource limitations sometimes necessitate siting magnetic resonance units in proximity to other institutional operations. For magnetic field shielding and personnel protection considerations, the generally accepted 0.5 mT (milliTesla) limit for implanted cardiac devices is commonly used as the conservative basis for decisions. But the effects of magnetic fields on equipment can be easily observed at levels far below 0.5 mT, often resulting in concern and apprehension on the part of personnel in the surrounding areas. Responding to recurrent worker concerns spawned by noticeable effects on equipment at exposure levels <0.5 mT can strain finite radiation safety program resources. To enhance the ability to anticipate possible facility incompatibility issues associated with the installation of magnetic sources, a literature review was conducted to summarize documented equipment effects. Various types of equipment were found to be impacted at levels ranging down to perhaps 0.001 mT. Armed with this information, practicing radiation safety professionals can better anticipate facility incompatibility issues and improve their responses to worker concerns initiated by observed effects on equipment.

Time-resolved absolute measurements by electro-optic effect of giant electromagnetic pulses due to laser-plasma interaction in nanosecond regime

PubMed Central

Consoli, F.; De Angelis, R.; Duvillaret, L.; Andreoli, P. L.; Cipriani, M.; Cristofari, G.; Di Giorgio, G.; Ingenito, F.; Verona, C.

2016-01-01

We describe the first electro-optical absolute measurements of electromagnetic pulses (EMPs) generated by laser-plasma interaction in nanosecond regime. Laser intensities are inertial-confinement-fusion (ICF) relevant and wavelength is 1054 nm. These are the first direct EMP amplitude measurements with the detector rather close and in direct view of the plasma. A maximum field of 261 kV/m was measured, two orders of magnitude higher than previous measurements by conductive probes on nanosecond regime lasers with much higher energy. The analysis of measurements and of particle-in-cell simulations indicates that signals match the emission of charged particles detected in the same experiment, and suggests that anisotropic particle emission from target, X-ray photoionization and charge implantation on surfaces directly exposed to plasma, could be important EMP contributions. Significant information achieved on EMP features and sources is crucial for future plants of laser-plasma acceleration and inertial-confinement-fusion and for the use as effective plasma diagnostics. It also opens to remarkable applications of laser-plasma interaction as intense source of RF-microwaves for studies on materials and devices, EMP-radiation-hardening and electromagnetic compatibility. The demonstrated extreme effectivity of electric-fields detection in laser-plasma context by electro-optic effect, leads to great potential for characterization of laser-plasma interaction and generated Terahertz radiation. PMID:27301704

Time-resolved absolute measurements by electro-optic effect of giant electromagnetic pulses due to laser-plasma interaction in nanosecond regime

NASA Astrophysics Data System (ADS)

Consoli, F.; de Angelis, R.; Duvillaret, L.; Andreoli, P. L.; Cipriani, M.; Cristofari, G.; di Giorgio, G.; Ingenito, F.; Verona, C.

2016-06-01

We describe the first electro-optical absolute measurements of electromagnetic pulses (EMPs) generated by laser-plasma interaction in nanosecond regime. Laser intensities are inertial-confinement-fusion (ICF) relevant and wavelength is 1054 nm. These are the first direct EMP amplitude measurements with the detector rather close and in direct view of the plasma. A maximum field of 261 kV/m was measured, two orders of magnitude higher than previous measurements by conductive probes on nanosecond regime lasers with much higher energy. The analysis of measurements and of particle-in-cell simulations indicates that signals match the emission of charged particles detected in the same experiment, and suggests that anisotropic particle emission from target, X-ray photoionization and charge implantation on surfaces directly exposed to plasma, could be important EMP contributions. Significant information achieved on EMP features and sources is crucial for future plants of laser-plasma acceleration and inertial-confinement-fusion and for the use as effective plasma diagnostics. It also opens to remarkable applications of laser-plasma interaction as intense source of RF-microwaves for studies on materials and devices, EMP-radiation-hardening and electromagnetic compatibility. The demonstrated extreme effectivity of electric-fields detection in laser-plasma context by electro-optic effect, leads to great potential for characterization of laser-plasma interaction and generated Terahertz radiation.

TH-B-204-03: TG-199: Implanted Markers for Radiation Treatment Verification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Z.

Implanted markers as target surrogates have been widely used for treatment verification, as they provide safe and reliable monitoring of the inter- and intra-fractional target motion. The rapid advancement of technology requires a critical review and recommendation for the usage of implanted surrogates in current field. The symposium, also reporting an update of AAPM TG 199 - Implanted Target Surrogates for Radiation Treatment Verification, will be focusing on all clinical aspects of using the implanted target surrogates for treatment verification and related issues. A wide variety of markers available in the market will be first reviewed, including radiopaque markers, MRImore » compatible makers, non-migrating coils, surgical clips and electromagnetic transponders etc. The pros and cons of each kind will be discussed. The clinical applications of implanted surrogates will be presented based on different anatomical sites. For the lung, we will discuss gated treatments and 2D or 3D real-time fiducial tracking techniques. For the prostate, we will be focusing on 2D-3D, 3D-3D matching and electromagnetic transponder based localization techniques. For the liver, we will review techniques when patients are under gating, shallow or free breathing condition. We will review techniques when treating challenging breast cancer as deformation may occur. Finally, we will summarize potential issues related to the usage of implanted target surrogates with TG 199 recommendations. A review of fiducial migration and fiducial derived target rotation in different disease sites will be provided. The issue of target deformation, especially near the diaphragm, and related suggestions will be also presented and discussed. Learning Objectives: Knowledge of a wide variety of markers Knowledge of their application for different disease sites Understand of issues related to these applications Z. Wang: Research funding support from Brainlab AG Q. Xu: Consultant for Accuray; Q. Xu, I am a consultant for Accuray planning service.« less

TH-B-204-00: Implanted Markers for Radiation Therapy and TG 199 Update

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Implanted markers as target surrogates have been widely used for treatment verification, as they provide safe and reliable monitoring of the inter- and intra-fractional target motion. The rapid advancement of technology requires a critical review and recommendation for the usage of implanted surrogates in current field. The symposium, also reporting an update of AAPM TG 199 - Implanted Target Surrogates for Radiation Treatment Verification, will be focusing on all clinical aspects of using the implanted target surrogates for treatment verification and related issues. A wide variety of markers available in the market will be first reviewed, including radiopaque markers, MRImore » compatible makers, non-migrating coils, surgical clips and electromagnetic transponders etc. The pros and cons of each kind will be discussed. The clinical applications of implanted surrogates will be presented based on different anatomical sites. For the lung, we will discuss gated treatments and 2D or 3D real-time fiducial tracking techniques. For the prostate, we will be focusing on 2D-3D, 3D-3D matching and electromagnetic transponder based localization techniques. For the liver, we will review techniques when patients are under gating, shallow or free breathing condition. We will review techniques when treating challenging breast cancer as deformation may occur. Finally, we will summarize potential issues related to the usage of implanted target surrogates with TG 199 recommendations. A review of fiducial migration and fiducial derived target rotation in different disease sites will be provided. The issue of target deformation, especially near the diaphragm, and related suggestions will be also presented and discussed. Learning Objectives: Knowledge of a wide variety of markers Knowledge of their application for different disease sites Understand of issues related to these applications Z. Wang: Research funding support from Brainlab AG Q. Xu: Consultant for Accuray; Q. Xu, I am a consultant for Accuray planning service.« less

Incorporation of hydrogen in CuInSe{sub 2}: Improvements of the structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yakushev, M. V.; Ogorodnikov, I. I.; Volkov, V. A.

2011-09-15

CuInSe{sub 2} single crystals were ion implanted with a dose of 3 x 10{sup 16} cm{sup -2} by 2.5 keV H{sup +} at 150 and 250 deg. C Before and after the implantation the crystals were analyzed by Rutherford backscattering/channeling (RBS/C) along the <112> axis using 2 MeV He{sup +}. The RBS/C spectra indicate that the implantation at 150 deg. C introduces a layer of radiation damage, whereas after the implantation at 250 deg. C no structural deterioration of the lattice can be seen. Quite the contrary, the RBS/C spectra reveal a considerable decrease in the dechanneling parameters suggesting improvementsmore » in the lattice structural quality attributed to the incorporation of hydrogen.« less

Surface-conductivity enhancement of PMMA by keV-energy metal-ion implantation

NASA Astrophysics Data System (ADS)

Bannister, M. E.; Hijazi, H.; Meyer, H. M.; Cianciolo, V.; Meyer, F. W.

2014-11-01

An experiment has been proposed to measure the neutron electric dipole moment (nEDM) with high precision at the Oak Ridge National Laboratory (ORNL) Spallation Neutron Source. One of the requirements of this experiment is the development of PMMA (Lucite) material with a sufficiently conductive surface to permit its use as a high-voltage electrode while immersed in liquid He. At the ORNL Multicharged Ion Research Facility, an R&D activity is under way to achieve suitable surface conductivity in poly-methyl methacrylate (PMMA) using metal ion implantation. The metal implantation is performed using an electron-cyclotron-resonance (ECR) ion source and a recently developed beam line deceleration module that is capable of providing high flux beams for implantation at energies as low as a few tens of eV. The latter is essential for reaching implantation fluences exceeding 1 × 1016 cm-2, where typical percolation thresholds in polymers have been reported. In this contribution, we report results on initial implantation of Lucite by Ti and W beams with keV energies to average fluences in the range 0.5-6.2 × 1016 cm-2. Initial measurements of surface-resistivity changes are reported as function of implantation fluence, energy, and sample temperature. We also report X-ray photoelectron spectroscopy (XPS) surface and depth profiling measurements of the ion implanted samples, to identify possible correlations between the near surface and depth resolved implanted W concentrations and the measured surface resistivities.

Adverse effects of nickel in transosseous wires and surgical implants: literature review.

PubMed

Nwashindi, A; Dim, E M

2014-01-01

Transosseous wires used in the management of fractures are stainless steel alloys which contain nickel 14.5%, chromium 17.6%, iron 62.5% and molybdenum 2.8%. Gradual disintegration of the transosseous wires release nickel into the blood leading to increase nickel concentration in the blood. Nickel has been found to have some adverse systemic effects on the body. The aim of this paper is to discuss the sources of Nickel in the body as well as the systemic adverse effects of Nickel as a degradation product of stainless steel surgical implants. A study of pertinent literature on nickel as a content of stainless steel alloy used in implant surgery was done, taking note also of other sources of nickel in the body, the toxicokinetics of nickel and the related adverse effects of this metal and its compound in humans. As outcome,the sources of human exposure to nickel,distribution and metabolism of nickel in the body, host responseto stainless steel wires and the adverse effects of nickel in the body are presented. It may be necessary to discourage the use of wires or implants containing nickel in the management of fractures.The need for removal of these implants after they have served their purposes is emphasized.

Ultraviolet radiation as disinfection for fish surgical tools

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, Ricardo W.; Markillie, Lye Meng; Colotelo, Alison HA

Telemetry is frequently used to examine the behavior of fish, and the transmitters used are normally surgically implanted into the coelomic cavity of fish. Implantation requires the use of surgical tools such as scalpels, forceps, needle holders, and sutures. When fish are implanted consecutively, as in large telemetry studies, it is common for surgical tools to be sterilized or, at minimum, disinfected between each use so that pathogens that may be present are not spread among fish. To determine the efficacy for this application, ultraviolet (UV) radiation was used to disinfect surgical tools exposed to one of four aquatic organismsmore » that typically lead to negative health issues for salmonids. These organisms included Aeromonas salmonicida, Flavobacterium psychrophilum, Renibacterium salmoninarum, and Saprolegnia parasitica, causative agents of furunculosis, coldwater disease, bacterial kidney disease, and saprolegniasis (water mold), respectively. Four experiments were conducted to address the question of UV efficacy. In the first experiment, forceps were exposed to the three bacteria at three varying concentrations. After exposure to the bacterial culture, tools were placed into a mobile Millipore UV sterilization apparatus. The tools were then exposed for three different time periods – 2, 5, or 15 min. UV radiation exposures at all durations were effective at killing all three bacteria on forceps at the highest bacteria concentrations. In the second experiment, stab scalpels, sutures, and needle holders were exposed to A. salmonicida using the same methodology as used in Experiment 1. UV radiation exposure at 5 and 15 min was effective at killing A. salmonicida on stab scalpels and sutures but not needle holders. In the third experiment, S. parasitica, a water mold, was tested using an agar plate method and forceps-pinch method. UV radiation was effective at killing the water mold at all three exposure durations. Collectively, this study shows that UV radiation appears to provide a quick alternative disinfection technique to chemical disinfectants (e.g., ethanol) for some surgical tools. However, we do not recommend using this method for tools such as needle holders having overlapping parts or other structures that cannot be exposed directly to UV radiation« less

Advances in prevention of radiation damage to visceral and solid organs in patients requiring radiation therapy of the trunk.

PubMed

Ritter, E F; Lee, C G; Tyler, D; Ferraro, F; Whiddon, C; Rudner, A M; Scully, S

1997-02-01

As a part of multimodality therapy, many patients with tumors of the trunk receive radiation therapy. The major morbidity of this therapy is often secondary to incidental radiation damage to tissues adjacent to treatment areas. We detail our use of saline breast implants placed in polyglycolic acid mesh sheets to displace visceral and solid organs away from the radiation field. Analysis of CT scans and dose volume histograms reveal that this technique successfully displaces uninvolved organs away from the radiation fields, thereby minimizing the radiation dose to such organs and tissues. We believe this is a safe and efficacious method to prevent radiation damage to visceral and solid organs adjacent to trunk tumor sites.

Iodine 125 source in interstitial tumor therapy. Clinical and biological considerations.

PubMed

Kim, J H; Hilaris, B

1975-01-01

Our clinical experience with interstitial tumor therapy is presented in 2 groups of patients: 98 patients with metastatic carcinoma in neck lymph nodes implanted with iodine 125, iridium 192 or radon 222 encapsulated sources, and 105 patients with primary unresectable lung tumors, which were implanted either with radon 222 or iodine 125 seeds. The local tumor control rates with iodine 125, radon 222 and iridium 192 were 78 per cent (38/49), 65 per cent (15/23) and 58 per cent (7/12), while the local complication rates were 17 per cent, 35 per cent and 43 per cent, respectively. An analysis of the tumor control rate as a function of the implanted tumor dose shows that the iodine 125 implants with a delivery of the minimal effective tumor dose of 16,000 rads have a higher therapeutic effect than either radon 222 or iridium 192. The results of the patients with unresectable lung tumors similarly show that the implants with iodine 125 sources are superior to those with radon 222. The advantages could stem from the better spatial dose distribution, and from radiobiologic considerations associated with low dose rates, continous irradiation, and possibly gains in RBE. There present clinical data clearly demonstrate that iodine 125 seeds have a higher therapeutic ratio than radon 222 seeds. There are, in addition, distinct physical advantages making iodine 125 an attractive substitute for radon 222 for the interstitial implantation of malignant tumors.

Magnet and Semi Precision Attachment in an Implant Retained Partial Denture for the Rehabilitation of an Irradiated Marginal Mandibulectomy Patient: A Case Report

PubMed Central

Guttal, Satyabodh Shesharaj; Kulkarni, Sudhindra S; Kudva, Adarsh; Thakur, Srinath

2015-01-01

Surgical treatment of malignancies in the oral cavity (mandible, tongue, floor of the mouth, alveolus, buccal sulcus) often results in an unfavourable anatomic condition for prosthodontic rehabilitation. Hence, maxillofacial prosthetic rehabilitation becomes a mightier task when resection is accompanied by radiation therapy. In selected cases, implant therapy comes to rescue. The following report throws light on the case of prosthetic rehabilitation of a patient who underwent right marginal mandibulectomy and right partial glossectomy, with the aid of a single implant, semi precision attachment and magnet supported partial denture. PMID:26501028

Management of radiation therapy patients with cardiac defibrillator or pacemaker.

PubMed

Salerno, Francesca; Gomellini, Sara; Caruso, Cristina; Barbara, Raffaele; Musio, Daniela; Coppi, Tamara; Cardinale, Mario; Tombolini, Vincenzo; de Paula, Ugo

2016-06-01

The increasing growth of population with cardiac implantable electronic devices (CIEDs) such as Pacemaker (PM) and Implantable Cardiac Defibrillators (ICD), requires particular attention in management of patients needing radiation treatment. This paper updates and summarizes some recommendations from different international guidelines. Ionizing radiation and/or electromagnetic interferences could cause device failure. Current approaches to treatment in patients who have these devices vary among radiation oncology centres. We refer to the German Society of Radiation Oncology and Cardiology guidelines (ed. 2015); to the Society of Cardiology Australia and New Zealand Statement (ed. 2015); to the guidelines in force in the Netherlands (ed. 2012) and to the Italian Association of Radiation Oncology recommendations (ed. 2013) as reported in the guidelines for the treatment of breast cancer in patients with CIED. Although there is not a clear cut-off point, risk of device failure increases with increasing doses. Cumulative dose and pacing dependency have been combined to categorize patients into low-, medium- and high-risk groups. Measures to secure patient safety are described for each category. The use of energy ≤6MV is preferable and it's strongly recommended not to exceed a total dose of 2 Gy to the PM and 1 Gy for ICD. Given the dangers of device malfunction, radiation oncology departments should adopt all the measures designed to minimize the risk to patients. For this reason, a close collaboration between cardiologist, radiotherapist and physicist is necessary.

Revisited study of fluorine implantation impact on negative bias temperature instability for input/output device of automotive micro controller unit

NASA Astrophysics Data System (ADS)

Yoshida, Tetsuya; Maekawa, Keiichi; Tsuda, Shibun; Shimizu, Tatsuo; Ogasawara, Makoto; Aono, Hideki; Yamaguchi, Yasuo

2018-04-01

We investigate the effect of fluorine implanted in the polycrystalline silicon (poly-Si) gate and source/drain (S/D) region on negative bias temperature instability (NBTI) improvement. It is found that there is a trade-off implantation energy dependence of NBTI between fluorine in the poly-Si gate and that in the S/D region. Fluorine implanted in the poly-Si gate contributes to NBTI improvement under low energy implantation. On the other hand, NBTI is improved by fluorine implanted in the S/D region under high energy. We propose that the two-step implantation process with high and low energy is the optimum condition for NBTI improvement.

Combined effects of radiation damage and He accumulation on bubble nucleation in Gd2Ti2O7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Caitlin A.; Patel, Maulik K.; Aguiar, Jeffery A.

2016-10-01

Pyrochlores have long been considered as host phases for long-term immobilization of radioactive waste nuclides that would undergo ..alpha..-decay for hundreds of thousands of years. This work utilizes ion-beam irradiations to examine the combined effects of radiation damage and He accumulation on bubble formation in Gd2Ti2O7 over relevant waste-form timescales. Helium bubbles are not observed in pre-damaged Gd2Ti2O7 implanted with 2 x 1016 He/cm2, even after post-implantation irradiations with 7 MeV Au3+ at 300, 500, and 700 K. However, He bubbles with average diameters of 1.5 nm and 2.1 nm are observed in pre-damaged (amorphous) Gd2Ti2O7 and pristine Gd2Ti2O7, respectively,more » after implantation of 2 x 1017 He/cm2. The critical He concentration for bubble nucleation in Gd2Ti2O7 is estimated to be 6 at.% He.« less

Ion radiation albedo effect: influence of surface roughness on ion implantation and sputtering of materials

NASA Astrophysics Data System (ADS)

Li, Yonggang; Yang, Yang; Short, Michael P.; Ding, Zejun; Zeng, Zhi; Li, Ju

2017-01-01

In fusion devices, ion retention and sputtering of materials are major concerns in the selection of compatible plasma-facing materials (PFMs), especially in the context of their microstructural conditions and surface morphologies. We demonstrate how surface roughness changes ion implantation and sputtering of materials under energetic ion irradiation. Using a new, sophisticated 3D Monte Carlo (MC) code, IM3D, and a random rough surface model, ion implantation and the sputtering yields of tungsten (W) with a surface roughness varying between 0-2 µm have been studied for irradiation by 0.1-1 keV D+, He+ and Ar+ ions. It is found that both ion backscattering and sputtering yields decrease with increasing roughness; this is hereafter called the ion radiation albedo effect. This effect is mainly dominated by the direct, line-of-sight deposition of a fraction of emitted atoms onto neighboring asperities. Backscattering and sputtering increase with more oblique irradiation angles. We propose a simple analytical formula to relate rough-surface and smooth-surface results.

Hysterosalpingography

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A novel self-aligned oxygen (SALOX) implanted SOI MOSFET device structure

NASA Astrophysics Data System (ADS)

Tzeng, J. C.; Baerg, W.; Ting, C.; Siu, B.

The morphology of the novel self-aligned oxygen implanted SOI (SALOX SOI) [1] MOSFET was studied. The channel silicon of SALOX SOI was confirmed to be undamaged single crystal silicon and was connected with the substrate. Buried oxide formed by oxygen implantation in this SALOX SOI structure was shown by a cross section transmission electron micrograph (X-TEM) to be amorphous. The source/drain silicon on top of the buried oxide was single crystal, as shown by the transmission electron diffraction (TED) pattern. The source/drain regions were elevated due to the buried oxide volume expansion. A sharp silicon—silicon dioxide interface between the source/drain silicon and buried oxide was observed by Auger electron spectroscopy (AES). Well behaved n-MOS transistor current voltage characteristics were obtained and showed no I-V kink.

Ring-shaped dysphotopsia associated with posterior chamber phakic implantable collamer lenses with a central hole.

PubMed

Eom, Youngsub; Kim, Dae Wook; Ryu, Dongok; Kim, Jun-Heon; Yang, Seul Ki; Song, Jong Suk; Kim, Sug-Whan; Kim, Hyo Myung

2017-05-01

To evaluate the incidence of central hole-induced ring-shaped dysphotopsia after posterior chamber phakic implantable collamer lens (ICL) with central hole (hole ICL) implantation and to investigate the causes of central hole-induced dysphotopsia. The clinical study enrolled 29 eyes of 15 consecutive myopic patients implanted with hole ICL. The incidence of ring-shaped dysphotopsia after hole ICL implantation was evaluated. In the experimental simulation study, non-sequential ray tracing was used to construct myopic human eye models with hole ICL and ICL without a central hole (conventional ICL). Simulated retinal images measured in log-scale irradiance were compared between the two ICLs for an extended Lambertian light-emitting disc object 20 cm in diameter placed 2 m from the corneal vertex. To investigate the causes of hole-induced dysphotopsia, a series of retinal images were simulated using point sources at infinity with well-defined field angles (0 to -20°) and multiple ICL models. Of 29 eyes, 15 experienced ring-shaped dysphotopsia after hole ICL implantation. The simulation study using an extended Lambertian source showed that hole ICL-evoked ring-shaped dysphotopsia was formed at a retinal field angle of ±40°. Component-level analysis using a well-defined off-axis point source from infinity revealed that ring-shaped dysphotopsia was generated by stray light refraction from the inner wall of the hole and the posterior ICL surface. Hole ICL-evoked ring-shaped dysphotopsia was related to light refraction at the central hole structure. Surgeons are advised to explain to patients the possibility of ring-shaped dysphotopsia after hole ICL implantation. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Benefits of Localization and Speech Perception with Multiple Noise Sources in Listeners with a Short-electrode Cochlear Implant

PubMed Central

Dunn, Camille C.; Perreau, Ann; Gantz, Bruce; Tyler, Richard

2009-01-01

Background Research suggests that for individuals with significant low-frequency hearing, implantation of a short-electrode cochlear implant may provide benefits of improved speech perception abilities. Because this strategy combines acoustic and electrical hearing within the same ear while at the same time preserving low-frequency residual acoustic hearing in both ears, localization abilities may also be improved. However, very little research has focused on the localization and spatial hearing abilities of users with a short-electrode cochlear implant. Purpose The purpose of this study was to evaluate localization abilities for listeners with a short-electrode cochlear implant who continue to wear hearing aids in both ears. A secondary purpose was to document speech perception abilities using a speech in noise test with spatially-separate noise sources. Research Design Eleven subjects that utilized a short-electrode cochlear implant and bilateral hearing aids were tested on localization and speech perception with multiple noise locations using an eight-loudspeaker array. Performance was assessed across four listening conditions using various combinations of cochlear implant and/or hearing aid use. Results Results for localization showed no significant difference between using bilateral hearing aids and bilateral hearing aids plus the cochlear implant. However, there was a significant difference between the bilateral hearing aid condition and the implant plus use of a contralateral hearing aid for all eleven subjects. Results for speech perception showed a significant benefit when using bilateral hearing aids plus the cochlear implant over use of the implant plus only one hearing aid. Conclusion Combined use of both hearing aids and the cochlear implant show significant benefits for both localization and speech perception in noise for users with a short-electrode cochlear implant. These results emphasize the importance of low-frequency information in two ears for the purpose of localization and speech perception in noise. PMID:20085199

Benefits of localization and speech perception with multiple noise sources in listeners with a short-electrode cochlear implant.

PubMed

Dunn, Camille C; Perreau, Ann; Gantz, Bruce; Tyler, Richard S

2010-01-01

Research suggests that for individuals with significant low-frequency hearing, implantation of a short-electrode cochlear implant may provide benefits of improved speech perception abilities. Because this strategy combines acoustic and electrical hearing within the same ear while at the same time preserving low-frequency residual acoustic hearing in both ears, localization abilities may also be improved. However, very little research has focused on the localization and spatial hearing abilities of users with a short-electrode cochlear implant. The purpose of this study was to evaluate localization abilities for listeners with a short-electrode cochlear implant who continue to wear hearing aids in both ears. A secondary purpose was to document speech perception abilities using a speech-in-noise test with spatially separate noise sources. Eleven subjects that utilized a short-electrode cochlear implant and bilateral hearing aids were tested on localization and speech perception with multiple noise locations using an eight-loudspeaker array. Performance was assessed across four listening conditions using various combinations of cochlear implant and/or hearing aid use. Results for localization showed no significant difference between using bilateral hearing aids and bilateral hearing aids plus the cochlear implant. However, there was a significant difference between the bilateral hearing aid condition and the implant plus use of a contralateral hearing aid for all 11 subjects. Results for speech perception showed a significant benefit when using bilateral hearing aids plus the cochlear implant over use of the implant plus only one hearing aid. Combined use of both hearing aids and the cochlear implant show significant benefits for both localization and speech perception in noise for users with a short-electrode cochlear implant. These results emphasize the importance of low-frequency information in two ears for the purpose of localization and speech perception in noise.

Assessment of magnetic field interactions and radiofrequency-radiation-induced heating of metallic spinal implants in 7 T field.

PubMed

Tsukimura, Itsuko; Murakami, Hideki; Sasaki, Makoto; Endo, Hirooki; Yamabe, Daisuke; Oikawa, Ryosuke; Doita, Minoru

2017-08-01

The safety of metallic spinal implants in magnetic resonance imaging (MRI) performed using ultrahigh fields has not been established. Hence, we examined whether the displacement forces caused by a static magnetic field and the heating induced by radiofrequency radiation are substantial for spinal implants in a 7 T field. We investigated spinal rods of various lengths and materials, a screw, and a cross-linking bridge in accordance with the American Society for Testing and Materials guidelines. The displacement forces of the metallic implants in static 7 T and 3 T static magnetic fields were measured and compared. The temperature changes of the implants during 15-min-long fast spin-echo and balanced gradient-echo image acquisition sequences were measured in the 7 T field. The deflection angles of the metallic spinal materials in the 7 T field were 5.0-21.0° [median: 6.7°], significantly larger than those in the 3 T field (1.0-6.3° [2.2°]). Among the metallic rods, the cobalt-chrome rods had significantly larger deflection angles (17.8-21.0° [19.8°]) than the pure titanium and titanium alloy rods (5.0-7.7° [6.2°]). The temperature changes of the implants, including the cross-linked rods, were 0.7-1.0°C [0.8°C] and 0.6-1.0°C [0.7°C] during the fast spin-echo and balanced gradient-echo sequences, respectively; these changes were slightly larger than those of the controls (0.4-1.1°C [0.5°C] and 0.3-0.9°C [0.6°C], respectively). All of the metallic spinal implants exhibited small displacement forces and minimal heating, indicating that MRI examinations using 7 T fields may be performed safely on patients with these implants. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:1831-1837, 2017. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society.

Using ILD or ITD Cues for Sound Source Localization and Speech Understanding in a Complex Listening Environment by Listeners with Bilateral and with Hearing-Preservation Cochlear Implants

ERIC Educational Resources Information Center

Loiselle, Louise H.; Dorman, Michael F.; Yost, William A.; Cook, Sarah J.; Gifford, Rene H.

2016-01-01

Purpose: To assess the role of interaural time differences and interaural level differences in (a) sound-source localization, and (b) speech understanding in a cocktail party listening environment for listeners with bilateral cochlear implants (CIs) and for listeners with hearing-preservation CIs. Methods: Eleven bilateral listeners with MED-EL…

Improved yields for MOST’s using ion implantation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brockman, H. E.

1976-04-01

Conventionally diffused source and drain polysilicon gate MOST's commonly exhibit one type of fault, namely, that of polysilicon-to-diffusion short circuits. Investigations into the yields of large-area devices fabricated using ion-implanted sources and drains are compared with those of diffused structures. An improved technology for the chemical shaping of the polysilicon gates, which improves the yields for both types of devices, is also described. (AIP)

Technique of after-loading interstitial implants.

PubMed

Syed, A M; Feder, B H

1977-01-01

Interstitial implants are either removable or permanent (and occasionally a combination of both). Permanent implants are generally utilized where tumors are not accessible enough to permit easy removal of sources or where accurate source distribution is less critical. They are useful for cancers of the lung, pancreas, prostate, bladder, lymph nodes, etc. Radon and gold-198 have been largely replaced by iodine-125. Our major interests are in the removable after-loading iridium-192 implant techniques. Template (steel guide) and non-template (plastic tube) techniques are utilized. Templates are preferred where the tumor volume can only be approached from one side and where accurate positioning of sources would otherwise be difficult. They are useful for cancers of the cervix, vagina, urethra, and rectum. Non-template (plastic tube) techniques are preferred where the tumor volume can be approached from at least two sides and where templates are either not feasible or not essential for accurate positioning of sources. The single needle non-template approach is useful for cancers of lip, nodes, and breast (plastic button) and for cancers of the oral cavity and oropharynx (gold button). The paired needle non-template approach is useful for cancers of the gum, retromolar trigone, and base of tongue (loop technique) and for cancers of the palate (arch technique). Procedures for each technique are described in detail.

Ultrahigh-current-density metal-ion implantation and diamondlike-hydrocarbon films for tribological applications

NASA Astrophysics Data System (ADS)

Wilbur, P. J.

1993-09-01

The metal-ion-implantation system used to implant metals into substrates are described. The metal vapor required for operation is supplied by drawing sufficient electron current from the plasma discharge to an anode-potential crucible so a solid, pure metal placed in the crucible will be heated to the point of vaporization. The ion-producing, plasma discharge is initiated within a graphite-ion-source body, which operates at high temperature, by using an argon flow that is turned off once the metal vapor is present. Extraction of ion beams several cm in diameter at current densities ranging to several hundred micro-A/sq cm on a target 50 cm downstream of the ion source were demonstrated using Mg, Ag, Cr, Cu, Si, Ti, V, B, and Zr. These metals were implanted into over 100 substrates (discs, pins, flats, wires). A model describing thermal stresses induced in materials (e.g. ceramic plates) during high-current-density implantation is presented. Tribological and microstructural characteristics of iron and 304-stainless-steel samples implanted with Ti or B are examined. Diamondlike-hydrocarbon coatings were applied to steel surfaces and found to exhibit good tribological performance.

Bone Implant Interface Investigation by Synchrotron Radiation X-Ray Microfluorescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calasans-Maia, M.; Sales, E.; Lopes, R. T.

2010-04-06

Zinc is known to play a relevant role in growth and development; it has stimulatory effects on in vitro and in vivo bone formation and an inhibitory effect on in vitro osteoclastic bone resorption. The inorganic component of the bone tissue is nonstoichiometric apatite; changes in the composition of hidroxyapatite are subject of studies in order to improve the tissue response after implantation. The objective of this study was to investigate the effect of 0.5% zinc-containing hydroxyapatite in comparison to hydroxyapatite on osseous repair of rabbit's tibia. Cylinders (2x6 mm) of both materials were produced according to the specification ofmore » the International Organization for Standardization. Ethics Commission on Teaching and Research in Animals approved this project (HUAP-195/06). Fifteen White New Zealand rabbits were submitted to general anesthesia and two perforations (2 mm) were made in each tibia for implantation of zinc-containing hydroxyapatite cylinders (left tibia) and hydroxyapatite cylinders (right tibia). After 1, 2 and 4 weeks, the animals were killed and one fragment of each tibia with the cylinder was collected and embedded in a methacrylate-based resin and cut into slices (approx200 {mu}m thickness), parallel to the implant's long axis with a precision diamond saw for Synchrotron Radiation X-ray Microfluorescence investigation. The accomplishment of the standard procedures helped the planning, execution and the comparative analysis of the results. The chemical and physical properties of the biomaterials were modified after its implantation and the incorporation of zinc. Both materials are biocompatible and promote osteoconduction and favored bone repair.« less

The treatment of solid tumors by alpha emitters released from 224Ra-loaded sources—internal dosimetry analysis

NASA Astrophysics Data System (ADS)

Arazi, L.; Cooks, T.; Schmidt, M.; Keisari, Y.; Kelson, I.

2010-02-01

Diffusing alpha-emitters radiation therapy (DART) is a proposed new form of brachytherapy, allowing the treatment of solid tumors by alpha particles. DART utilizes implantable sources carrying small activities of radium-224, which continually release into the tumor radon-220, polonium-216 and lead-212 atoms, while radium-224 itself remains fixed to the source. The released atoms disperse inside the tumor by diffusive and convective processes, creating, through their alpha emissions, a high-dose region measuring several mm in diameter about each source. The efficacy of DART has been demonstrated in preclinical studies on mice-borne squamous cell carcinoma and lung tumors and the method is now being developed toward clinical trials. This work studies DART safety with respect to the dose delivered to distant organs as a result of lead-212 leakage from the tumor through the blood, relying on a biokinetic calculation coupled to internal dose assessments. It is found that the dose-limiting organs are the kidneys and red bone marrow. Assuming a typical source spacing of ~5 mm and a typical radium-224 activity density of 0.4-0.8 MBq g-1 of tumor tissue, it is predicted that tumors weighing up to several hundred grams may be treated without reaching the tolerance dose in any organ.

Influence of High-Power Pulsed IR Laser Radiation on the Electrophysical Properties of Cd x Hg1- x Те Heteroepitaxial Layers

NASA Astrophysics Data System (ADS)

Talipov, N. Kh.

2013-05-01

Results of investigations into the electrophysical properties of p- and n-type Cd x Hg1- x Te heteroepitaxial layers grown by molecular beam and liquid phase epitaxy methods after exposure to high-power pulsed IR radiation of solid-state Nd3+:YAG and chemical DF lasers at wavelengths of 1.06 and 3.8-4.2 μm, respectively, are presented. It is demonstrated that the main types of defects resulting from pulsed irradiation are mercury vacancies that play the role of acceptors in this material. The spatial distribution of generated mercury vacancies depends on the intensity and wavelength of laser radiation: the defects generated by pulses of the Nd3+:YAG laser are concentrated only near the surface, whereas DF-laser radiation creates defects in the entire volume of the heteroepitaxial structures. It is established that irradiation with the Nd3+:YAG laser of the p-Cd x Hg1- x Te heteroepitaxial layers implanted by boron ions leads to the activation of implanted boron atoms as a result of melting and recrystallization of the irradiated surface layer.

Management of patients with cardiac implantable electronic devices (CIED) undergoing radiotherapy: A consensus document from Associazione Italiana Aritmologia e Cardiostimolazione (AIAC), Associazione Italiana Radioterapia Oncologica (AIRO), Associazione Italiana Fisica Medica (AIFM).

PubMed

Zecchin, Massimo; Severgnini, Mara; Fiorentino, Alba; Malavasi, Vincenzo Livio; Menegotti, Loris; Alongi, Filippo; Catanzariti, Domenico; Jereczek-Fossa, Barbara Alicja; Stasi, Michele; Russi, Elvio; Boriani, Giuseppe

2018-03-15

The management of patients with a cardiac implanted electronic device (CIED) receiving radiotherapy (RT) is challenging and requires a structured multidisciplinary approach. A consensus document is presented as a result of a multidisciplinary working group involving cardiac electrophysiologists, radiation oncologists and physicists in order to stratify the risk of patients with CIED requiring RT and approaching RT sessions appropriately. When high radiation doses and beam energy higher than 6MV are used, CIED malfunctions can occur during treatment. In our document, we reviewed the different types of RT and CIED behavior in the presence of ionizing radiations and electromagnetic interferences, from the cardiologist's, radiation oncologist's and medical physicist's point of view. We also reviewed in vitro and in vivo literature data and other national published guidelines on this issue so far. On the basis of literature data and consensus of experts, a detailed approach based on risk stratification and appropriate management of RT patients with CIEDs is suggested, with important implications for clinical practice. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

[Evaluation of Radiation Dose during Stent-graft Treatment Using a Hybrid Operating Room System].

PubMed

Haga, Yoshihiro; Chida, Kouichi; Kaga, Yuji; Saitou, Kazuhisa; Arai, Takeshi; Suzuki, Shinichi; Iwaya, Yoshimi; Kumasaka, Eriko; Kataoka, Nozomi; Satou, Naoto; Abe, Mitsuya

2015-12-01

In recent years, aortic aneurysm treatment with stent graft grafting in the X-ray fluoroscopy is increasing. This is an endovascular therapy, because it is a treatment which includes the risk of radiation damage, having to deal with radiation damage, to know in advance is important. In this study, in order to grasp the trend of exposure stent graft implantation in a hybrid operating room (OR) system, focusing on clinical data (entrance skin dose and fluoroscopy time), was to count the total. In TEVAR and EVAR, fluoroscopy time became 13.40 ± 7.27 minutes, 23.67 ± 11.76 minutes, ESD became 0.87 ± 0.41 mGy, 1.11 ± 0.57 mGy. (fluoroscopy time of EVAR was 2.0 times than TEVAR. DAP of EVAR was 1.2 times than TEVAR.) When using the device, adapted lesions and usage are different. This means that care changes in exposure-related factors. In this study, exposure trends of the stent graft implantation was able to grasp. It can be a helpful way to reduce/optimize the radiation dose in a hybrid OR system.

A process modification for CMOS monolithic active pixel sensors for enhanced depletion, timing performance and radiation tolerance

NASA Astrophysics Data System (ADS)

Snoeys, W.; Aglieri Rinella, G.; Hillemanns, H.; Kugathasan, T.; Mager, M.; Musa, L.; Riedler, P.; Reidt, F.; Van Hoorne, J.; Fenigstein, A.; Leitner, T.

2017-11-01

For the upgrade of its Inner Tracking System, the ALICE experiment plans to install a new tracker fully constructed with monolithic active pixel sensors implemented in a standard 180 nm CMOS imaging sensor process, with a deep pwell allowing full CMOS within the pixel. Reverse substrate bias increases the tolerance to non-ionizing energy loss (NIEL) well beyond 1013 1 MeVneq /cm2, but does not allow full depletion of the sensitive layer and hence full charge collection by drift, mandatory for more extreme radiation tolerance. This paper describes a process modification to fully deplete the epitaxial layer even with a small charge collection electrode. It uses a low dose blanket deep high energy n-type implant in the pixel array and does not require significant circuit or layout changes so that the same design can be fabricated both in the standard and modified process. When exposed to a 55 Fe source at a reverse substrate bias of -6 V, pixels implemented in the standard and the modified process in a low and high dose variant for the deep n-type implant respectively yield a signal of about 115 mV, 110 mV and 90 mV at the output of a follower circuit. Signal rise times heavily affected by the speed of this circuit are 27 . 8 + / - 5 ns, 23 . 2 + / - 4 . 2 ns, and 22 . 2 + / - 3 . 7 ns rms, respectively. In a different setup, the single pixel signal from a 90 Sr source only degrades by less than 20% for the modified process after a 1015 1 MeVneq /cm2 irradiation, while the signal rise time only degrades by about 16 + / - 2 ns to 19 + / - 2 . 8 ns rms. From sensors implemented in the standard process no useful signal could be extracted after the same exposure. These first results indicate the process modification maintains low sensor capacitance, improves timing performance and increases NIEL tolerance by at least an order of magnitude.

Printed Multi-Turn Loop Antenna for RF Bio-Telemetry

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Hall, David G.; Miranda, Felix A.

2004-01-01

In this paper, a novel printed multi-turn loop antenna for contact-less powering and RF telemetry from implantable bio- MEMS sensors at a design frequency of 300 MHz is demonstrated. In addition, computed values of input reactance, radiation resistance, skin effect resistance, and radiation efficiency for the printed multi-turn loop antenna are presented. The computed input reactance is compared with the measured values and shown to be in fair agreement. The computed radiation efficiency at the design frequency is about 24 percent.

Body Implanted Medical Device Communications

NASA Astrophysics Data System (ADS)

Yazdandoost, Kamya Yekeh; Kohno, Ryuji

The medical care day by day and more and more is associated with and reliant upon concepts and advances of electronics and electromagnetics. Numerous medical devices are implanted in the body for medical use. Tissue implanted devices are of great interest for wireless medical applications due to the promising of different clinical usage to promote a patient independence. It can be used in hospitals, health care facilities and home to transmit patient measurement data, such as pulse and respiration rates to a nearby receiver, permitting greater patient mobility and increased comfort. As this service permits remote monitoring of several patients simultaneously it could also potentially decrease health care costs. Advancement in radio frequency communications and miniaturization of bioelectronics are supporting medical implant applications. A central component of wireless implanted device is an antenna and there are several issues to consider when designing an in-body antenna, including power consumption, size, frequency, biocompatibility and the unique RF transmission challenges posed by the human body. The radiation characteristics of such devices are important in terms of both safety and performance. The implanted antenna and human body as a medium for wireless communication are discussed over Medical Implant Communications Service (MICS) band in the frequency range of 402-405MHz.

Surgical positioning of orthodontic mini-implants with guides fabricated on models replicated with cone-beam computed tomography.

PubMed

Kim, Seong-Hun; Choi, Yong-Suk; Hwang, Eui-Hwan; Chung, Kyu-Rhim; Kook, Yoon-Ah; Nelson, Gerald

2007-04-01

This article illustrates a new surgical guide system that uses cone-beam computed tomography (CBCT) images to replicate dental models; surgical guides for the proper positioning of orthodontic mini-implants were fabricated on the replicas, and the guides were used for precise placement. The indications, efficacy, and possible complications of this method are discussed. Patients who were planning to have orthodontic mini-implant treatment were recruited for this study. A CBCT system (PSR 9000N, Asahi Roentgen, Kyoto, Japan) was used to acquire virtual slices of the posterior maxilla that were 0.1 to 0.15 mm thick. Color 3-dimensional rapid prototyping was used to differentiate teeth, alveolus, and maxillary sinus wall. A surgical guide for the mini-implant was fabricated on the replica model. Proper positioning for mini-implants on the posterior maxilla was determined by viewing the CBCT images. The surgical guide was placed on the clinical site, and it allowed precise pilot drilling and accurate placement of the mini-implant. CBCT imaging allows remarkably lower radiation doses and thinner acquisition slices compared with medical computed tomography. Virtually reproduced replica models enable precise planning for mini-implant positions in anatomically complex sites.

Biodegradable magnesium-based implants in bone studied by synchrotron radiation microtomography

NASA Astrophysics Data System (ADS)

Moosmann, Julian; Zeller-Plumhoff, Berit; Wieland, D. C. Florian; Galli, Silvia; Krüger, Diana; Dose, Thomas; Burmester, Hilmar; Wilde, Fabian; Bech, Martin; Peruzzi, Niccolò; Wiese, Björn; Hipp, Alexander; Beckmann, Felix; Hammel, Jörg; Willumeit-Römer, Regine

2017-09-01

Permanent implants made of titanium or its alloys are the gold standard in many orthopedic and traumatological applications due to their good biocompatibility and mechanical properties. However, a second surgical intervention is required for this kind of implants as they have to be removed in the case of children that are still growing or on patient's demand. Therefore, magnesium-based implants are considered for medical applications as they are degraded under physiological conditions. The major challenge is tailoring the degradation in a manner that is suitable for a biological environment and such that stabilization of the bone is provided for a controlled period. In order to understand failure mechanisms of magnesium-based implants in orthopedic applications and, further, to better understand the osseointegration, screw implants in bone are studied under mechanical load by means of a push-out device installed at the imaging beamline P05 of PETRA III at DESY. Conventional absorption contrast microtomography and phasecontrast techniques are applied in order to monitor the bone-to-implant interface under increasing load conditions. In this proof-of-concept study, first results from an in situ push-out experiment are presented.

Origin of magnetic properties in carbon implanted ZnO nanowires.

PubMed

Wang, Y F; Shao, Y C; Hsieh, S H; Chang, Y K; Yeh, P H; Hsueh, H C; Chiou, J W; Wang, H T; Ray, S C; Tsai, H M; Pao, C W; Chen, C H; Lin, H J; Lee, J F; Wu, C T; Wu, J J; Chang, Y M; Asokan, K; Chae, K H; Ohigashi, T; Takagi, Y; Yokoyama, T; Kosugi, N; Pong, W F

2018-05-17

Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C + ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies. The X-ray magnetic circular dichroism spectra of O and C K-edge respectively indicate there is a reduction in the number of unpaired/dangling O 2p bonds in the surface region of ZnO-C:NW and the C 2p-derived states of the implanted C ions strongly affect the net spin polarization in the surface and bulk regions of ZnO-C:NW. Furthermore, these findings corroborate well with the first-principles calculations of C-implanted ZnO in surface and bulk regions, which highlight the stability of implanted C for the suppression and enhancement of the ferromagnetism of the ZnO-C:NW in the surface region and bulk phase, respectively.

Prostate tumor alignment and continuous, real-time adaptive radiation therapy using electromagnetic fiducials: clinical and cost-utility analyses.

PubMed

Quigley, Martin M; Mate, Timothy P; Sylvester, John E

2009-01-01

To evaluate the accuracy, utility, and cost effectiveness of a new electromagnetic patient positioning and continuous, real-time monitoring system, which uses permanently implanted resonant transponders in the target (Calypso 4D Localization System and Beacon transponders, Seattle, WA) to continuously monitor tumor location and movement during external beam radiation therapy of the prostate. This clinical trial studied 43 patients at 5 sites. All patients were implanted with 3 transponders each. In 41 patients, the system was used for initial alignment at each therapy session. Thirty-five patients had continuous monitoring during their radiation treatment. Over 1,000 alignment comparisons were made to a commercially available kV X-ray positioning system (BrainLAB ExacTrac, Munich, Germany). Using decision analysis and Markov processes, the outcomes of patients were simulated over a 5-year period and measured in terms of costs from a payer's perspective and quality-adjusted life years (QALYs). All patients had satisfactory transponder implantations for monitoring purposes. In over 75% of the treatment sessions, the correction to conventional positioning (laser and tattoos) directed by an electromagnetic patient positioning and monitoring system was greater than 5 mm. Ninety-seven percent (34/35) of the patients who underwent continuous monitoring had target motion that exceeded preset limits at some point during the course of their radiation therapy. Exceeding preset thresholds resulted in user intervention at least once during the therapy in 80% of the patients (28/35). Compared with localization using ultrasound, electronic portal imaging devices (EPID), or computed tomography (CT), localization with the electromagnetic patient positioning and monitoring system yielded superior gains in QALYs at comparable costs. Most patients positioned with conventional tattoos and lasers for prostate radiation therapy were found by use of the electromagnetic patient positioning and monitoring system to have alignment errors exceeding 5 mm. Almost all patients undergoing external beam radiation of the prostate have been shown to have target organ movement exceeding 3 mm during radiation therapy delivery. The ability of the electromagnetic technology to monitor tumor target location during the same time as radiation therapy is being delivered allows clinicians to provide real time adaptive radiation therapy for prostate cancer. This permits clinicians to intervene when the prostate moves outside the radiation isocenter, which should decrease adverse events and improve patient outcomes. Additionally, a cost-utility analysis has demonstrated that the electromagnetic patient positioning and monitoring system offers patient outcome benefits at a cost that falls well within the payer's customary willingness to pay (WTP) threshold of $50,000 per QALY.

A novel radiation protection drape reduces radiation exposure during fluoroscopy guided electrophysiology procedures.

PubMed

Germano, Joseph J; Day, Gina; Gregorious, David; Natarajan, Venkataraman; Cohen, Todd

2005-09-01

The purpose of this study was to evaluate a novel disposable lead-free radiation protection drape for decreasing radiation scatter during electrophysiology procedures. In recent years, there has been an exponential increase in the number of electrophysiology (EP) procedures exposing patients, operators and laboratory staff to higher radiation doses. The RADPAD was positioned slightly lateral to the incision site for pectoral device implants and superior to the femoral vein during electrophysiology studies. Each patient served as their own control and dosimetric measurements were obtained at the examiner's elbow and hand. Radiation badge readings for the operator were obtained three months prior to RADPAD use and three months after introduction. Radiation dosimetry was obtained in twenty patients: 7 electrophysiology studies, 6 pacemakers, 5 catheter ablations, and 2 implantable cardioverter-defibrillators. Eleven women and nine men with a mean age of 63 +/- 4 years had an average fluoroscopy time of 2.5 +/- 0.42 minutes per case. Mean dosimetric measurements at the hand were reduced from 141.38 +/- 24.67 to 48.63 +/- 9.02 milliroentgen (mR) per hour using the protective drape (63% reduction; p < 0.0001). Measurements at the elbow were reduced from 78.78 +/- 7.95 mR per hour to 34.50 +/- 4.18 mR per hour using the drape (55% reduction; p < 0.0001). Badge readings for three months prior to drape introduction averaged 2.45 mR per procedure versus 1.54 mR per procedure for 3 months post-initiation (37% reduction). The use of a novel radiation protection surgical drape can significantly reduce scatter radiation exposure to staff and operators during a variety of EP procedures.

Effects of H-implantation on the optical stability under photo-irradiation of urushi films

NASA Astrophysics Data System (ADS)

Awazu, Kaoru; Nishimura, Yoshinori; Ichikawa, Tachio; Sakamoto, Makoto; Watanabe, Hiroshi; Iwaki, Masaya

1993-06-01

A study has been made of the effects of H-implantation on the optical stability under photo-irradiation of urushi films. Urushi films of 43 μm in thickness were lacquered on glass plates. Implantation of H +, H 2+, C +, N + and O + ions were performed with an energy of 150 keV and doses of 1 × 10 14 and 1 × 10 15 ions/cm 2 at room temperature. The beam current density used was approximately 1 μA/cm 2 to prevent specimens from heating. The photo-irradiation onto the surfaces of urushi films was carried out to radiative exposure of 190 MJ/m 2, using a Suga sunshine weather meter. The gloss, transmittance and haze of implanted and photo-irradiated urushi films have been investigated in conjunction with chemical bonding states of carbon at the urushi surfaces. Ion implantation induces the surface carbonization of urushi films to inhibit the change in gloss and haze by photo-irradiation. It is concluded that ion implantation is useful for improving the optical stability under photo-irradiation of urushi films.

Electronic excitation effects on nanoparticle formation in insulators under heavy-ion implantation

NASA Astrophysics Data System (ADS)

Kishimoto, N.; Plaksin, O. A.; Masuo, K.; Okubo, N.; Umeda, N.; Takeda, Y.

2006-01-01

Kinetic processes of nanoparticle formation by ion implantation was studied for the insulators of a-SiO2, LiNbO3, MgO · 2.4(Al2O3) and PMMA, either by changing ion flux or by using a co-irradiation technique of ions and photons. Under Cu-implantation of 60 keV Cu-, nanoparticles spontaneously formed without thermal annealing, indicating radiation-induced diffusion of implants. The high-flux implantation caused instable behaviors of nanoparticle morphology in a-SiO2, LiNbO3 and PMMA, i.e. enhanced atomic rearrangement or loss of nanoparticles. The spinel MgO · 2.4(Al2O3) also showed nanoparticle precipitation at 60 keV, but the precipitation tendency is less than the others. Combined irradiation of 3 MeV Cu ions and photons of 2.3 eV or 3.5 eV indicates that the electronic excitation during ion implantation significantly enhances nanoparticle precipitation, greatly depending on photon energy and fluence. The selectivity for photons can be applied to control nanoparticle precipitation.

Multi-Polarization Reconfigurable Antenna for Wireless Biomedical System.

PubMed

Wong, Hang; Lin, Wei; Huitema, Laure; Arnaud, Eric

2017-06-01

This paper presents a multi-polarization reconfigurable antenna with four dipole radiators for biomedical applications in body-centric wireless communication system (BWCS). The proposed multi-dipole antenna with switchable 0°, +45°, 90° and -45° linear polarizations is able to overcome the polarization mismatching and multi-path distortion in complex wireless channels as in BWCS. To realize this reconfigurable feature for the first time among all the reported antenna designs, we assembled four dipoles together with 45° rotated sequential arrangements. These dipoles are excited by the same feeding source provided by a ground tapered Balun. A metallic reflector is placed below the dipoles to generate a broadside radiation. By introducing eight PIN diodes as RF switches between the excitation source and the four dipoles, we can control a specific dipole to operate. As the results, 0°, +45°, 90° and -45° linear polarizations can be switched correspondingly to different operating dipoles. Experimental results agree with the simulation and show that the proposed antenna well works in all polarization modes with desirable electrical characteristics. The antenna has a wide impedance bandwidth of 34% from 2.2 to 3.1 GHz (for the reflection coefficient ≤ -10 dB) and exhibits a stable cardioid-shaped radiation pattern across the operating bandwidth with a peak gain of 5.2 dBi. To validate the effectiveness of the multi-dipole antenna for biomedical applications, we also designed a meandered PIFA as the implantable antenna. Finally, the communication link measurement shows that our proposed antenna is able to minimize the polarization mismatching and maintains the optimal communication link thanks to its polarization reconfigurability.

Long-Term Outcomes of Alternative Brachytherapy Techniques for Early Prostate Cancer. Addendum

DTIC Science & Technology

2008-10-01

radical prostatectomy. The National Medicare Experience: 1988-1990 (updated June 1993). Urology 1993;42:622-9. 3. Litwin MS, Hays RD, Fink A, Ganz PA...implantation for early-stage prostatic cancer. J Clin Oncol 1999;17:517-22. 33. Brandeis JM, Litwin MS, Burnison CM, Reiter RE. Quality of life outcomes after...combination radiotherapy for patients with prostate cancer. I-125 implant followed by external-beam radiation. Cancer 1995;75:2383-91. 35. Litwin M

Surface characterization and biodegradation behavior of magnesium implanted poly(L-lactide/caprolactone) films

NASA Astrophysics Data System (ADS)

Sokullu, Emel; Ersoy, Fulya; Yalçın, Eyyup; Öztarhan, Ahmet

2017-11-01

Biopolymers are great source for medical applications such as drug delivery, wound patch, artificial tissue studies etc., food packaging, cosmetic applications etc. due to their biocompatibility and biodegradability. Particularly, the biodegradation ability of a biomaterial makes it even advantageous for the applications. The more tunable the biodegradation rate the more desired the biopolymers. There are many ways to tune degradation rate including surface modification. In this study ion implantation method applied to biopolymer surface to determine its effect on biodegradation rate. In this study, surface modification of poly(L-lactide/caprolactone) copolymer film is practiced via Mg-ion-implantation using a MEVVA ion source. Mg ions were implanted at a fluence of 1 × 1015 ions/cm2 and ion energy of 30 keV. Surface characterization of Mg-ion-implanted samples is examined using Atomic Force Microscopy, Raman spectroscopy, contact angle measurement and FT-IR Spectroscopy. These analyses showed that the surface become more hydrophilic and rougher after the ion implantation process which is advantageous for cell attachment on medical studies. The in vitro enzymatic degradation of Mg-implanted samples was investigated in Lipase PS containing enzyme solution. Enzymatic degradation rate was examined by mass loss calculation and it is shown that Mg-implanted samples lost more than 30% of their weight while control samples lost around 20% of their weight at the end of the 16 weeks. The evaluation of the results confirmed that Mg-ion-implantation on poly(L-lactide/caprolactone) films make the surface rougher and more hydrophilic and changes the organic structure on the surface. On the other hand, ion implantation has increased the biodegradation rate.

Prostate implant nomograms for the North American scientific {sup 103}Pd seed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jay J.; Stevens, Ritchie N

Palladium-103-({sup 103}Pd) seed has been increasingly used in prostate implantation as either definitive or boost therapy because of its shorter half-life and higher initial dose rate. Because a growing number of radiation oncologists prefer real-time implantation in the operating room, it will be helpful if the total activity of the seeds can be determined based on the gland size before the patient is taken to the operating room. Based on our clinic data, nomograms have therefore been developed for one of the widely used {sup 103}Pd seeds, the MED3633 seed, which is produced by North American Scientific, Inc. (NASI). Themore » total activities for implant volume ranging from 15 cc to 55 cc are provided for both seed 'monotherapy' and seed boost.« less

Compositional transformations in ion implanted polymers

NASA Astrophysics Data System (ADS)

Abdul-Kader, A. M.; Turos, A.; Grambole, D.; Jagielski, J.; Piątkowska, A.; Madi, N. K.; Al-Maadeed, M.

2005-10-01

Changes of surface layer composition produced by ion bombardment of polyethylene and polypropylene samples were studied. These materials are under consideration for load bearing surfaces in biological and technical applications. To improve their tribological properties, surface layers are usually modified by ionizing radiation. Therefore, to study the mechanism of transformations induced by ion beam bombardment selected polymers were implanted with H, He and Ar ions to the fluences ranging from 1 × 1013 to 2 × 1016/cm2. RBS and NRA techniques were applied for sample analysis. Important hydrogen release was observed with increasing ion dose and was correlated with the ion stopping power. Another important effect observed was the rapid oxidation of samples, which apparently occurs after exposure of implanted samples to the air. Up to 10 at.% of oxygen can be incorporated in the implanted layer.

Single frequency RF powered ECG telemetry system

NASA Technical Reports Server (NTRS)

Ko, W. H.; Hynecek, J.; Homa, J.

1979-01-01

It has been demonstrated that a radio frequency magnetic field can be used to power implanted electronic circuitry for short range telemetry to replace batteries. A substantial reduction in implanted volume can be achieved by using only one RF tank circuit for receiving the RF power and transmitting the telemetered information. A single channel telemetry system of this type, using time sharing techniques, was developed and employed to transmit the ECG signal from Rhesus monkeys in primate chairs. The signal from the implant is received during the period when the RF powering radiation is interrupted. The ECG signal is carried by 20-microsec pulse position modulated pulses, referred to the trailing edge of the RF powering pulse. Satisfactory results have been obtained with this single frequency system. The concept and the design presented may be useful for short-range long-term implant telemetry systems.

Resorbable fixation in facial plastic and head and neck reconstructive surgery: an initial report on polylactic acid implants.

PubMed

Moe, K S; Weisman, R A

2001-10-01

The purpose of this study was to evaluate and report our initial experience with a resorbable fixation system in facial cosmetic and head and neck reconstructive surgery. The specific goals were to determine in which settings the absorbable system could be used, to evaluate the outcome of its use, to detail complications that occurred, and to report our observations on advantages and disadvantages of the system compared with traditional methods of osteosynthesis and fixation. A retrospective review of the initial 30 consecutive patients at the University of California, San Diego Division of Head and Neck Surgery who received polylactic acid (PLA) implants. Academic tertiary referral/level I trauma center. Criteria for inclusion into the study were any patient over age 18 who underwent a procedure involving the use of a PLA implant between March 1999 and October 2000. In addition to the typical indications for metal plate or mesh implantation, PLA was used for "protected bone regeneration." Detailed records were kept of all patients in whom PLA implants were used, including the exact procedure and type of implant. All patients were operated by the authors. Operative reports, hospital charts, and office records were analyzed for any perioperative or postoperative complications. The attending surgeon noted advantages and disadvantages of the system. Patients have been followed from 2 to 18 months at the time of this report and are part of an ongoing long-term follow-up study. PLA implants were used in 35 procedures on 30 consecutive patients (multiple unilateral fracture repairs were counted as a single procedure). Uses included fixation of craniofacial fractures (zygomaticomaxillary, orbit floor, frontal bone [N = 9]; fixation of craniofacial osteotomy [N = 8]; protected bone regeneration [N = 3]; mandible, cranial bone donor site [N = 2]; bone grafting [N = 2]; craniectomy reconstruction [N = 2], and soft tissue suspension [endoscopic browlifting, N = 6, static facial suspension, N = 1]). There were 4 complications in this series: 2 partial flap losses, 1 in a patient who had had preoperative radiation and the other in a heavy smoker; 1 infected cranial bone flap in a patient who had had two prior surgeries and radiation; and 1 wound dehiscence over a plate that was improperly contoured. Advantages noted by the surgeons were ease of contouring the mesh or plates, including in situ reshaping, apparent decrease in operative time, low implant profile, minimal soft tissue reaction, and radiolucency of the system, allowing postoperative imaging without metallic artifact. We found the PLA system to be highly effective, and noted no absolute contraindications to its use compared with standard metal plating systems. The 11% incidence of complications in this series was acceptable and probably not the result of the PLA implant material, although further experience is needed to determine the role of PLA implants in radiated tissue. The primary advantages to PLA appear to be its ease of use, radiolucency, eventual resorption, and, possibly, improved precision of reduction. The use in protected bone regeneration may also be an advantage, but long-term follow-up of our population will be needed to determine this. Based on short-term outcome analysis of our initial experience with PLA implantation, it appears to be an efficacious and safe technology for applications in head and neck and facial plastic surgery.

Implantable Myoelectric Sensors (IMESs) for Intramuscular Electromyogram Recording

PubMed Central

Weir, Richard F. ff.; Troyk, Phil R.; DeMichele, Glen A.; Kerns, Douglas A.; Schorsch, Jack F.; Maas, Huub

2011-01-01

We have developed a multichannel electrogmyography sensor system capable of receiving and processing signals from up to 32 implanted myoelectric sensors (IMES). The appeal of implanted sensors for myoelectric control is that electromyography (EMG) signals can be measured at their source providing relatively cross-talk-free signals that can be treated as independent control sites. An external telemetry controller receives telemetry sent over a transcutaneous magnetic link by the implanted electrodes. The same link provides power and commands to the implanted electrodes. Wireless telemetry of EMG signals from sensors implanted in the residual musculature eliminates the problems associated with percutaneous wires, such as infection, breakage, and marsupialization. Each implantable sensor consists of a custom-designed application-specified integrated circuit that is packaged into a bio-compatible RF BION capsule from the Alfred E. Mann Foundation. Implants are designed for permanent long-term implantation with no servicing requirements. We have a fully operational system. The system has been tested in animals. Implants have been chronically implanted in the legs of three cats and are still completely operational four months after implantation. PMID:19224729

Totally Implantable Wireless Ultrasonic Doppler Blood Flowmeters: Toward Accurate Miniaturized Chronic Monitors.

PubMed

Rothfuss, Michael A; Unadkat, Jignesh V; Gimbel, Michael L; Mickle, Marlin H; Sejdić, Ervin

2017-03-01

Totally implantable wireless ultrasonic blood flowmeters provide direct-access chronic vessel monitoring in hard-to-reach places without using wired bedside monitors or imaging equipment. Although wireless implantable Doppler devices are accurate for most applications, device size and implant lifetime remain vastly underdeveloped. We review past and current approaches to miniaturization and implant lifetime extension for wireless implantable Doppler devices and propose approaches to reduce device size and maximize implant lifetime for the next generation of devices. Additionally, we review current and past approaches to accurate blood flow measurements. This review points toward relying on increased levels of monolithic customization and integration to reduce size. Meanwhile, recommendations to maximize implant lifetime should include alternative sources of power, such as transcutaneous wireless power, that stand to extend lifetime indefinitely. Coupling together the results will pave the way for ultra-miniaturized totally implantable wireless blood flow monitors for truly chronic implantation. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Hernia Surgical Mesh Implants

MedlinePlus

... Surgical Clinics of North America; 83(5):1045-51, v-vi. 2 . http://www.facs.org/public_ ... FDA Contact FDA Browse by Product Area Product Areas back Food Drugs Medical Devices Radiation-Emitting Products ...

Longterm infrared neural stimulation in the chronic implanted cat

NASA Astrophysics Data System (ADS)

Matic, Agnella Izzo; Robinson, Alan M.; Young, Hunter K.; Badofsky, Ben; Rajguru, Suhrud M.; Richter, Claus-Peter

2013-03-01

Among neural prostheses cochlear implants (CIs) are considered the most successful devices. They restore some hearing to 210,000 severe-to-profound hearing impaired people. Despite the devices' success, the performance of the implanted individuals in noisy environments is poor and music perception is rudimentary. It has been argued that increasing the number of independent channels for stimulation can improve the performance of a CI user in challenging hearing environments. An optical method, stimulating neurons with infrared radiation, has been suggested as a novel approach to increase the number of independent channels. Infrared neural stimulation (INS) works through the deposition of heat into the tissue. Thermal damage is therefore a potential risk, particularly for longterm exposure. To verify the efficacy and safety of INS, cats were implanted for about 4 weeks and were continuously stimulated daily for 6-8 hours. Cochlear function did not change during the stimulation, and histology did not reveal signs of damage. Tissue growth following the implantation was largely localized at the cochleostomy.

Multiple ion beam irradiation for the study of radiation damage in materials

NASA Astrophysics Data System (ADS)

Taller, Stephen; Woodley, David; Getto, Elizabeth; Monterrosa, Anthony M.; Jiao, Zhijie; Toader, Ovidiu; Naab, Fabian; Kubley, Thomas; Dwaraknath, Shyam; Was, Gary S.

2017-12-01

The effects of transmutation produced helium and hydrogen must be included in ion irradiation experiments to emulate the microstructure of reactor irradiated materials. Descriptions of the criteria and systems necessary for multiple ion beam irradiation are presented and validated experimentally. A calculation methodology was developed to quantify the spatial distribution, implantation depth and amount of energy-degraded and implanted light ions when using a thin foil rotating energy degrader during multi-ion beam irradiation. A dual ion implantation using 1.34 MeV Fe+ ions and energy-degraded D+ ions was conducted on single crystal silicon to benchmark the dosimetry used for multi-ion beam irradiations. Secondary Ion Mass Spectroscopy (SIMS) analysis showed good agreement with calculations of the peak implantation depth and the total amount of iron and deuterium implanted. The results establish the capability to quantify the ion fluence from both heavy ion beams and energy-degraded light ion beams for the purpose of using multi-ion beam irradiations to emulate reactor irradiated microstructures.

Pharmacological doses of daily ascorbate protect tumors from radiation damage after a single dose of radiation in an intracranial mouse glioma model.

PubMed

Grasso, Carole; Fabre, Marie-Sophie; Collis, Sarah V; Castro, M Leticia; Field, Cameron S; Schleich, Nanette; McConnell, Melanie J; Herst, Patries M

2014-01-01

Pharmacological ascorbate is currently used as an anti-cancer treatment, potentially in combination with radiation therapy, by integrative medicine practitioners. In the acidic, metal-rich tumor environment, ascorbate acts as a pro-oxidant, with a mode of action similar to that of ionizing radiation; both treatments kill cells predominantly by free radical-mediated DNA damage. The brain tumor, glioblastoma multiforme (GBM), is very resistant to radiation; radiosensitizing GBM cells will improve survival of GBM patients. Here, we demonstrate that a single fraction (6 Gy) of radiation combined with a 1 h exposure to ascorbate (5 mM) sensitized murine glioma GL261 cells to radiation in survival and colony-forming assays in vitro. In addition, we report the effect of a single fraction (4.5 Gy) of whole brain radiation combined with daily intraperitoneal injections of ascorbate (1 mg/kg) in an intracranial GL261 glioma mouse model. Tumor-bearing C57BL/6 mice were divided into four groups: one group received a single dose of 4.5 Gy to the brain 8 days after tumor implantation, a second group received daily intraperitoneal injections of ascorbate (day 8-45) after implantation, a third group received both treatments and a fourth control group received no treatment. While radiation delayed tumor progression, intraperitoneal ascorbate alone had no effect on tumor progression. Tumor progression was faster in tumor-bearing mice treated with radiation and daily ascorbate than in those treated with radiation alone. Histological analysis showed less necrosis in tumors treated with both radiation and ascorbate, consistent with a radio-protective effect of ascorbate in vivo. Discrepancies between our in vitro and in vivo results may be explained by differences in the tumor microenvironment, which determines whether ascorbate remains outside the cell, acting as a pro-oxidant, or whether it enters the cells and acts as an anti-oxidant.

Reduction of metal artifacts: beam hardening and photon starvation effects

NASA Astrophysics Data System (ADS)

Yadava, Girijesh K.; Pal, Debashish; Hsieh, Jiang

2014-03-01

The presence of metal-artifacts in CT imaging can obscure relevant anatomy and interfere with disease diagnosis. The cause and occurrence of metal-artifacts are primarily due to beam hardening, scatter, partial volume and photon starvation; however, the contribution to the artifacts from each of them depends on the type of hardware. A comparison of CT images obtained with different metallic hardware in various applications, along with acquisition and reconstruction parameters, helps understand methods for reducing or overcoming such artifacts. In this work, a metal beam hardening correction (BHC) and a projection-completion based metal artifact reduction (MAR) algorithms were developed, and applied on phantom and clinical CT scans with various metallic implants. Stainless-steel and Titanium were used to model and correct for metal beam hardening effect. In the MAR algorithm, the corrupted projection samples are replaced by the combination of original projections and in-painted data obtained by forward projecting a prior image. The data included spine fixation screws, hip-implants, dental-filling, and body extremity fixations, covering range of clinically used metal implants. Comparison of BHC and MAR on different metallic implants was used to characterize dominant source of the artifacts, and conceivable methods to overcome those. Results of the study indicate that beam hardening could be a dominant source of artifact in many spine and extremity fixations, whereas dental and hip implants could be dominant source of photon starvation. The BHC algorithm could significantly improve image quality in CT scans with metallic screws, whereas MAR algorithm could alleviate artifacts in hip-implants and dentalfillings.

The Efficacy of Ultraviolet Radiation for Sterilizing Tools Used for Surgically Implanting Transmitters into Fish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, Ricardo W.; Markillie, Lye Meng; Colotelo, Alison HA

Telemetry is frequently used to examine the behavior of fish, and the transmitters used are normally surgically implanted into the coelom of fish. Implantation requires the use of surgical tools such as scalpels, forceps, needle holders, and sutures. When several fish are implanted consecutively for large telemetry studies, it is common for surgical tools to be sterilized or, at minimum, disinfected between each use so that pathogens that may be present are not spread among fish. However, autoclaving tools can take a long period of time, and chemical sterilants or disinfectants can be harmful to both humans and fish andmore » have varied effectiveness. Ultraviolet (UV) radiation is commonly used to disinfect water in aquaculture facilities. However, this technology has not been widely used to sterilize tools for surgical implantation of transmitters in fish. To determine its efficacy for this application, Pacific Northwest National Laboratory researchers used UV radiation to disinfect surgical tools (i.e., forceps, needle holder, stab scalpel, and suture) that were exposed to one of four aquatic organisms that typically lead to negative health issues for salmonids. These organisms included Aeromonas salmonicida, Flavobacterium psychrophilum, Renibacterium salmoninarum, and Saprolegnia parasitica. Surgical tools were exposed to the bacteria by dipping them into a confluent suspension of three varying concentrations (i.e., low, medium, high). After exposure to the bacterial culture, tools were placed into a mobile Millipore UV sterilization apparatus. The tools were then exposed for three different time periods—2, 5, or 15 min. S. parasitica, a water mold, was tested using an agar plate method and forceps-pinch method. UV light exposures of 5 and 15 min were effective at killing all four organisms. UV light was also effective at killing Geobacillus stearothermophilus, the organism used as a biological indicator to verify effectiveness of steam sterilizers. These techniques appear to provide a quick alternative disinfection technique for some surgical tools that is less harmful to both humans and fish while not producing chemical waste. However, we do not recommend using these methods with tools that have overlapping parts or other structures that cannot be directly exposed to UV light such as needle holders.« less

The boron implantation in the varied zone MBE MCT epilayer

NASA Astrophysics Data System (ADS)

Voitsekhovskii, Alexander V.; Grigor'ev, Denis V.; Kokhanenko, Andrey P.; Korotaev, Alexander G.; Sidorov, Yuriy G.; Varavin, Vasiliy S.; Dvoretsky, Sergey A.; Mikhailov, Nicolay N.; Talipov, Niyaz Kh.

2005-09-01

In the paper experimental results on boron implantation of the CdxHg1-xTe epilayers with various composition near surface of the material are discussed. The electron concentration in the surface layer after irradiation vs irradiation dose and ion energy are investigated for range of doses 1011 - 3•1015 cm-2 and energies of 20 - 150 keV. Also the results of the electrical active defects distribution measurement, carried out by differential Hall method, after boron implantation are represented. Consideration of the received data shows, that composition gradient influence mainly on the various dynamics of accumulation of electric active radiation defects. The electric active defects distribution analysis shows, that the other factors are negligible.

Formation of a periodic diffractive structure based on poly(methyl methacrylate) with ion-implanted silver nanoparticles

NASA Astrophysics Data System (ADS)

Galyautdinov, M. F.; Nuzhdin, V. I.; Fattakhov, Ya. V.; Farrakhov, B. F.; Valeev, V. F.; Osin, Yu. N.; Stepanov, A. L.

2016-02-01

We propose to form optical diffractive elements on the surface of poly(methyl methacrylate) (PMMA) by implanting the polymer with silver ions ( E = 30 keV; D = 5.0 × 1014 to 1.5 × 1017 ion/cm2; I = 2 μA/cm2) through a nickel grid (mask). Ion implantation leads to the nucleation and growth of silver nanoparticles in unmasked regions of the polymer. The formation of periodic surface microstructures during local sputtering of the polymer by incident ions was monitored using an optical microscope. The diffraction efficiency of obtained gratings is demonstrated under conditions of their probing with semiconductor laser radiation in the visible spectral range.

Dosimetric effects of seed anisotropy and interseed attenuation for {sup 103}Pd and {sup 125}I prostate implants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chibani, Omar; Williamson, Jeffrey F.; Todor, Dorin

2005-08-15

A Monte Carlo study is carried out to quantify the effects of seed anisotropy and interseed attenuation for {sup 103}Pd and {sup 125}I prostate implants. Two idealized and two real prostate implants are considered. Full Monte Carlo simulation (FMCS) of implants (seeds are physically and simultaneously simulated) is compared with isotropic point-source dose-kernel superposition (PSKS) and line-source dose-kernel superposition (LSKS) methods. For clinical pre- and post-procedure implants, the dose to the different structures (prostate, rectum wall, and urethra) is calculated. The discretized volumes of these structures are reconstructed using transrectal ultrasound contours. Local dose differences (PSKS versus FMCS and LSKSmore » versus FMCS) are investigated. The dose contributions from primary versus scattered photons are calculated separately. For {sup 103}Pd, the average absolute total dose difference between FMCS and PSKS can be as high as 7.4% for the idealized model and 6.1% for the clinical preprocedure implant. Similarly, the total dose difference is lower for the case of {sup 125}I: 4.4% for the idealized model and 4.6% for a clinical post-procedure implant. Average absolute dose differences between LSKS and FMCS are less significant for both seed models: 3 to 3.6% for the idealized models and 2.9 to 3.2% for the clinical plans. Dose differences between PSKS and FMCS are due to the absence of both seed anisotropy and interseed attenuation modeling in the PSKS approach. LSKS accounts for seed anisotropy but not for the interseed effect, leading to systematically overestimated dose values in comparison with the more accurate FMCS method. For both idealized and clinical implants the dose from scattered photons represent less than 1/3 of the total dose. For all studied cases, LSKS prostate DVHs overestimate D{sub 90} by 2 to 5% because of the missing interseed attenuation effect. PSKS and LSKS predictions of V{sub 150} and V{sub 200} are overestimated by up to 9% in comparison with the FMCS results. Finally, effects of seed anisotropy and interseed attenuation must be viewed in the context of other significant sources of dose uncertainty, namely seed orientation, source misplacement, prostate morphological changes and tissue heterogeneity.« less

The contents of dental implant patient information leaflets available within the UK.

PubMed

Barber, J; Puryer, J; McNally, L; O'Sullivan, D

2015-02-01

Patient information leaflets are designed to provide easy to follow information summaries and first point of contact information about treatment options. This survey reviewed the content of dental implant patient information leaflets, produced by implant companies and available within the UK in 2011. Dental implant companies in the UK were asked to provide samples of their patient information leaflets. The information within the leaflets was then summarised, including the quantity and the types of images used and whether the source of the information was given. Quantitative data was obtained on the amount of information provided, size of images and number of references. A response rate of 71% was obtained and 23 leaflets were studied. Great variation was found between the leaflets, with the word counts ranging from 88 to 5,434, and 44 different topics were identified. The majority of the images used were decorative, and none of the leaflets gave any reference to the sources of their information. Implant treatment was generally described in a positive way, with an emphasis on describing the treatment and the advantages. Much less information was given about the potential disadvantages and risks of complications or failure, including the relevance of periodontal disease or smoking. Implant patient information leaflets provided by dental implant companies should not be solely relied upon to provide patients with all the information they need to give informed consent to treatment.

Development of pulsed processes for the manufacture of solar cells. Quarterly progress report No. 3, April--July 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1978-07-01

Third quarter results under a program to develop ion implantation and specialized, associated processes necessary to achieve automated production of silicon solar cells are described. An ion implantation facility development for solar cell production is described, and a design for an automated production implanter is presented. Also, solar cell development efforts using combined ion implantation and pulsed energy techniques are discussed. Cell performance comparisons have also been made in which junctions and back surface fields were prepared by diffusion and ion implantation. A model is presented to explain the mechanism of ion implantation damage annealing using pulsed energy sources. Functionalmore » requirements have been determined for a pulsed electron beam processor for annealing ion implantation damage at a rate compatible with a 100 milliampere ion implanter. These rates result in a throughput of 100 megawatts of solar cell product per year.« less

Development of an Implantable Myoelectric Sensor for Advanced Prosthesis Control

PubMed Central

Merrill, Daniel R.; Lockhart, Joseph; Troyk, Phil R.; Weir, Richard F.; Hankin, David L.

2013-01-01

Modern hand and wrist prostheses afford a high level of mechanical sophistication, but the ability to control them in an intuitive and repeatable manner lags. Commercially available systems using surface electromyographic (EMG) or myoelectric control can supply at best two degrees of freedom (DOF), most often sequentially controlled. This limitation is partially due to the nature of surface-recorded EMG, for which the signal contains components from multiple muscle sources. We report here on the development of an implantable myoelectric sensor using EMG sensors that can be chronically implanted into an amputee’s residual muscles. Because sensing occurs at the source of muscle contraction, a single principal component of EMG is detected by each sensor, corresponding to intent to move a particular effector. This system can potentially provide independent signal sources for control of individual effectors within a limb prosthesis. The use of implanted devices supports inter-day signal repeatability. We report on efforts in preparation for human clinical trials, including animal testing, and a first-in-human proof of principle demonstration where the subject was able to intuitively and simultaneously control two DOF in a hand and wrist prosthesis. PMID:21371058

TEM observations of radiation damage in tungsten irradiated by 20 MeV W ions

NASA Astrophysics Data System (ADS)

Ciupiński, Ł.; Ogorodnikova, O. V.; Płociński, T.; Andrzejczuk, M.; Rasiński, M.; Mayer, M.; Kurzydłowski, K. J.

2013-12-01

Polycrystalline, recrystallized W targets were subjected to implantation with 20 MeV W6+ ions in order to simulate radiation damage caused by fusion neutrons. Three samples with cumulative damage of 0.01, 0.1 and 0.89 dpa were produced. The near-surface zone of each sample has been analyzed by transmission electron microscopy (TEM). To this end, lamellae oriented perpendicularly to the targets implanted surface were milled out using focused ion beam (FIB). A reference lamella from non-irradiated, recrystallized W target was also prepared to estimate the damage introduced during FIB processing. TEM studies revealed a complex microstructure of the damaged zones as well as its evolution with cumulative damage level. The experimentally observed damage depth agrees very well with the one calculated using the Stopping and Range of Ions in Matter (SRIM) software.

Hyperfine interactions of trans-lead elements studied by nuclear radiations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ansaldo, E.J.

1973-09-16

The applications of nuclear radiation methods to the study of hyperfine interactions (hfi) for elements beyond Pb in the periodic table are reviewed. A general discussion of hfi is presented along with a review of specific methods. The techniques are illustrated whenever possible by their application to the actinides, with emphasis on the unsolved aspects of the results. A special method of sample preparation is ion implantation, in which stable or radioactive ions of practically any element are shot into the host, either by means of isotope separators or the recoil energy of nuclear reactions or radioactive decays. The locationmore » of the implanted (recoiled) atom in the lattice has to be assessed for a reliable determination of the hfi. Therefore, a chapter on the channeling technique is also included. (JRD)« less

SU-C-303-04: Evaluation of On- and Off-Line Bioluminescence Tomography System for Focal Irradiation Guidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, B; Wang, K; Reyes, J

Purpose: We have developed offline and on-board bioluminescence tomography(BLT) systems for the small animal radiation research platform(SARRP) for radiation guidance of soft tissue targets. We investigated the effectiveness of offline BLT guidance. Methods: CBCT is equipped on both the offline BLT system and SARRP that are 10 ft. apart. To evaluate the setup error during animal transport between the two systems, we implanted a luminescence source in the abdomen of anesthetized mice. Five mice were studied. After CBCT was acquired on both systems, source centers and correlation coefficients were calculated. CBCT was also used to generate object mesh for BLTmore » reconstruction. To assess target localization, we compared the localization of the luminescence source based on (1)on-board SARRP BLT and CBCT, (2)offline BLT and CBCT, and (3)offline BLT and SARRP CBCT. The 3rd comparison examines if an offline BLT system can be used to guide radiation when there is minimal target contrast in CBCT. Results: Our CBCT results show the offset of the light source center can be maintained within 0.2 mm during animal transport. The center of mass(CoM) of the light source reconstructed by the offline BLT has an offset of 1.0 ± 0.4 mm from the ‘true’ CoM as derived from the SARRP CBCT. The results compare well with the offset of 1.0 ± 0.2 mm using on-line BLT. Conclusion: With CBCT information provided by the SARRP and effective animal immobilization during transport, these findings support the use of offline BLT in close vicinity for accurate soft tissue target localization for irradiation. However, the disadvantage of the off-line system is reduced efficiency as care is required to maintain stable animal transport. We envisage a dual use system where the on-board arrangement allows convenient access to CBCT and avoids disturbance of animal setup. The off-line capability would support standalone longitudinal imaging studies. The work is supported by NIH R01CA158100 and Xstrahl Ltd. Drs. John Wong and Iulian Iordachita receive royalty payment from a licensing agreement between Xstrahl Ltd and Johns Hopkins University. John Wong also has a consultant agreement with Xstrahl Ltd.« less

Influence of displacement damage on deuterium and helium retention in austenitic and ferritic-martensitic alloys considered for ADS service

NASA Astrophysics Data System (ADS)

Voyevodin, V. N.; Karpov, S. A.; Kopanets, I. E.; Ruzhytskyi, V. V.; Tolstolutskaya, G. D.; Garner, F. A.

2016-01-01

The behavior of ion-implanted hydrogen (deuterium) and helium in austenitic 18Cr10NiTi stainless steel, EI-852 ferritic steel and ferritic/martensitic steel EP-450 and their interaction with displacement damage were investigated. Energetic argon irradiation was used to produce displacement damage and bubble formation to simulate nuclear power environments. The influence of damage morphology and the features of radiation-induced defects on deuterium and helium trapping in structural alloys was studied using ion implantation, the nuclear reaction D(3He,p)4He, thermal desorption spectrometry and transmission electron microscopy. It was found in the case of helium irradiation that various kinds of helium-radiation defect complexes are formed in the implanted layer that lead to a more complicated spectra of thermal desorption. Additional small changes in the helium spectra after irradiation with argon ions to a dose of ≤25 dpa show that the binding energy of helium with these traps is weakly dependent on the displacement damage. It was established that retention of deuterium in ferritic and ferritic-martensitic alloys is three times less than in austenitic steel at damage of ∼1 dpa. The retention of deuterium in steels is strongly enhanced by presence of radiation damages created by argon ion irradiation, with a shift in the hydrogen release temperature interval of 200 K to higher temperature. At elevated temperatures of irradiation the efficiency of deuterium trapping is reduced by two orders of magnitude.

3D tumor tissue analogs and their orthotopic implants for understanding tumor-targeting of microenvironment-responsive nanosized chemotherapy and radiation.

PubMed

Sethi, Pallavi; Jyoti, Amar; Swindell, Elden P; Chan, Ryan; Langner, Ulrich W; Feddock, Jonathan M; Nagarajan, Radhakrishnan; O'Halloran, Thomas V; Upreti, Meenakshi

2015-11-01

An appropriate representation of the tumor microenvironment in tumor models can have a pronounced impact on directing combinatorial treatment strategies and cancer nanotherapeutics. The present study develops a novel 3D co-culture spheroid model (3D TNBC) incorporating tumor cells, endothelial cells and fibroblasts as color-coded murine tumor tissue analogs (TTA) to better represent the tumor milieu of triple negative breast cancer in vitro. Implantation of TTA orthotopically in nude mice, resulted in enhanced growth and aggressive metastasis to ectopic sites. Subsequently, the utility of the model is demonstrated for preferential targeting of irradiated tumor endothelial cells via radiation-induced stromal enrichment of galectin-1 using anginex conjugated nanoparticles (nanobins) carrying arsenic trioxide and cisplatin. Demonstration of a multimodal nanotherapeutic system and inclusion of the biological response to radiation using an in vitro/in vivo tumor model incorporating characteristics of tumor microenvironment presents an advance in preclinical evaluation of existing and novel cancer nanotherapies. Existing in-vivo tumor models are established by implanting tumor cells into nude mice. Here, the authors described their approach 3D spheres containing tumor cells, enodothelial cells and fibroblasts. This would mimic tumor micro-environment more realistically. This interesting 3D model should reflect more accurately tumor response to various drugs and would enable the design of new treatment modalities. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Restoration of orbicularis oculi muscle function in rabbits with peripheral facial paralysis via an implantable artificial facial nerve system

PubMed Central

Sun, Yajing; Jin, Cheng; Li, Keyong; Zhang, Qunfeng; Geng, Liang; Liu, Xundao; Zhang, Yi

2017-01-01

The purpose of the present study was to restore orbicularis oculi muscle function using the implantable artificial facial nerve system (IAFNS). The in vivo part of the IAFNS was implanted into 12 rabbits that were facially paralyzed on the right side of the face to restore the function of the orbicularis oculi muscle, which was indicated by closure of the paralyzed eye when the contralateral side was closed. Wireless communication links were established between the in vivo part (the processing chip and microelectrode) and the external part (System Controller program) of the system, which were used to set the working parameters and indicate the working state of the processing chip and microelectrode implanted in the body. A disturbance field strength test of the IAFNS processing chip was performed in a magnetic field dark room to test its electromagnetic radiation safety. Test distances investigated were 0, 1, 3 and 10 m, and levels of radiation intensity were evaluated in the horizontal and vertical planes. Anti-interference experiments were performed to test the stability of the processing chip under the interference of electromagnetic radiation. The fully implanted IAFNS was run for 5 h per day for 30 consecutive days to evaluate the accuracy and precision as well as the long-term stability and effectiveness of wireless communication. The stimulus intensity (range, 0–8 mA) was set every 3 days to confirm the minimum stimulation intensity which could indicate the movement of the paralyzed side was set. Effective stimulation rate was also tested by comparing the number of eye-close movements on both sides. The results of the present study indicated that the IAFNS could rebuild the reflex arc, inducing the experimental rabbits to close the eye of the paralyzed side. The System Controller program was able to reflect the in vivo part of the artificial facial nerve system in real-time and adjust the working pattern, stimulation intensity and frequency, range of wave and stimulation time. No significant differences in the stimulus intensities were observed during 30 days. The artificial facial nerve system chip operation stable in the anti-interference test, and the radiation field strength of the system was in a safe range according to the national standard. The IAFNS functioned without any interference and was able to restore functionality to facially paralyzed rabbits over the course of 30 days. PMID:29285055

Adaptors for radiation detectors

DOEpatents

Livesay, Ronald Jason

2014-04-22

Described herein are adaptors and other devices for radiation detectors that can be used to make accurate spectral measurements of both small and large bulk sources of radioactivity, such as building structures, soils, vessels, large equipment, and liquid bodies. Some exemplary devices comprise an adaptor for a radiation detector, wherein the adaptor can be configured to collimate radiation passing through the adapter from an external radiation source to the radiation detector and the adaptor can be configured to enclose a radiation source within the adapter to allow the radiation detector to measure radiation emitted from the enclosed radiation source.

Adaptors for radiation detectors

DOEpatents

Livesay, Ronald Jason

2015-07-28

Described herein are adaptors and other devices for radiation detectors that can be used to make accurate spectral measurements of both small and large bulk sources of radioactivity, such as building structures, soils, vessels, large equipment, and liquid bodies. Some exemplary devices comprise an adaptor for a radiation detector, wherein the adaptor can be configured to collimate radiation passing through the adapter from an external radiation source to the radiation detector and the adaptor can be configured to enclose a radiation source within the adapter to allow the radiation detector to measure radiation emitted from the enclosed radiation source.

[Effects of optical radiation in ocular structures].

PubMed

Pascu, Ruxandra Angela

2007-01-01

The eye and the skin are organs that are particularly vulnerable to external aggression, such as electromagnetic radiation- meaning ultraviolet radiation, visible radiation (especially blue light) and infrared radiation. The three mechanisms involved are: the photo-thermic mechanism, the photochemical mechanism and the photomechanical mechanism. The effects of such exposures can be either temporary or permanent, if inadequate protection occurs. Today, there are enough data so that special protection measures can be taken concerning the potential damage of optical radiation. Among those, we mention artificial implants or sun glasses containing UV filters or surgical gestures that can be taken to protect the eye against the surgical light. Ultimately, the effects of optical radiation upon the eye are related to being well informed about the risks of uncontrolled exposure and the protection measures against it.

Development of a new, completely implantable intraventricular pressure meter and preliminary report of its clinical experience

NASA Technical Reports Server (NTRS)

Osaka, K.; Murata, T.; Okamoto, S.; Ohta, T.; Ozaki, T.; Maeda, T.; Mori, K.; Handa, H.; Matsumoto, S.; Sakaguchi, I.

1982-01-01

A completely implantable intracranial pressure sensor designed for long-term measurement of intraventricular pressure in hydrocephalic patients is described. The measurement principal of the device is discussed along with the electronic and component structure and sources of instrument error. Clinical tests of this implanted pressure device involving both humans and animals showed it to be comparable to other methods of intracranial pressure measurement.

Outcomes of Fat-Augmented Latissimus Dorsi (FALD) Flap Versus Implant-Based Latissimus Dorsi Flap for Delayed Post-radiation Breast Reconstruction.

PubMed

Demiri, Efterpi C; Dionyssiou, Dimitrios D; Tsimponis, Antonios; Goula, Christina-Olga; Pavlidis, Leonidas C; Spyropoulou, Georgia-Alexandra

2018-06-01

Although free abdominal flaps constitute the gold standard in post-radiation delayed breast reconstruction, latissimus dorsi-based methods offer alternative reconstructive options. This retrospective study aims to compare outcomes of delayed breast reconstruction using the fat-augmented latissimus dorsi (FALD) autologous reconstruction and the latissimus dorsi-plus-implant reconstruction in irradiated women. We reviewed the files of 47 post-mastectomy irradiated patients (aged 29-73 years), who underwent delayed latissimus dorsi-based breast reconstruction between 2010 and 2016. Twenty-three patients (Group A) had an extended FALD flap and twenty-four patients (Group B) an implant-based latissimus dorsi reconstruction. Patients' age, BMI, pregnancies, volume of injected fat, implant size, postoperative complications, and secondary surgical procedures were recorded and analyzed. Age, BMI, pregnancies, and donor-site complications were similar in both groups (p > 0.05). Mean fat volume injected initially was 254 cc (ranged 130-380 cc/session); mean implant volume was 323 cc (ranged 225-420 cc). Breast complications were significantly fewer in Group A (one wound dehiscence, two oily cysts) compared to Group B (three cases with wound dehiscence, two extrusions, thirteen severe capsular contractions). Non-statistically significant difference was documented for secondary procedures between groups; although the mean number of additional surgeries/patient was higher in Group A, they referred to secondary lipofilling, whereas in Group B they were revision surgeries for complications. The FALD flap constitutes an alternative method for delayed autologous reconstruction after post-mastectomy irradiation, avoiding implant-related complications. Although additional fat graft sessions might be required, it provides an ideal autogenous reconstructive option for thin nulliparous women, with a small opposite breast and adequate fat donor sites. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Carrier mobility degradation due to high dose implantation in ultrathin unstrained and strained silicon-on-insulator films

NASA Astrophysics Data System (ADS)

Dupré, C.; Ernst, T.; Hartmann, J.-M.; Andrieu, F.; Barnes, J.-P.; Rivallin, P.; Faynot, O.; Deleonibus, S.; Fazzini, P. F.; Claverie, A.; Cristoloveanu, S.; Ghibaudo, G.; Cristiano, F.

2007-11-01

Based on electrical measurements and transmission electron microscopy (TEM) imaging, we propose an explanation for the electron and hole mobility degradation with gate length reduction in metal-oxide-semiconductor field effect transistors (MOSFETs). We demonstrate that ion implantation, normally used for source/drain doping, is responsible for transport degradation for short-channel devices. Implantation impact on electrons and holes mobility was investigated both on silicon-on-insulator (SOI) and tensile strained silicon-on-insulator (sSOI) substrates. Wafers with ultrathin Si films (from 8 to 35 nm) were Ge implanted at 3 keV and various concentrations (from 5×1014 to 2×1015 atoms cm-2), then annealed at 600 °C for 1 h. Secondary ion mass spectrometry enabled us to quantify the Ge-implanted atoms concentrations. The end-of-range defects impact on mobility was investigated with the pseudo-MOSFET technique. Measurements showed a mobility decrease as the implantation dose increased. We demonstrated that sSOI mobility is more sensitive to implantation than SOI mobility, without any implantation-induced strain relaxation in sSOI (checked using the ultraviolet Raman technique). A 36% (25%) holes (electrons) mobility degradation was measured for sSOI, while SOI presented a 21% mobility degradation for holes and 5% for electrons. Finally, the electrical results were compared with morphological studies. Plan-view TEM showed the presence of interstitial defects formed during ion implantation and annealing. The defect density was estimated to be two times higher in sSOI than in SOI, which is in full agreement with electrical results mentioned before. The results are relevant for the optimization of the source and drain regions of advanced nanoscale SOI and sSOI transistors.

76 FR 6692 - Radiation Sources on Army Land

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-08

...-AA58 Radiation Sources on Army Land AGENCY: Department of the Army, DoD. ACTION: Final rule. SUMMARY: The Department of the Army is finalizing revisions to its regulation concerning radiation sources on... Radiation Permit (ARP) from the garrison commander to use, store, or possess ionizing radiation sources on...

Design and simulation of printed spiral coil used in wireless power transmission systems for implant medical devices.

PubMed

Wu, Wei; Fang, Qiang

2011-01-01

Printed Spiral Coil (PSC) is a coil antenna for near-field wireless power transmission to the next generation implant medical devices. PSC for implant medical device should be power efficient and low electromagnetic radiation to human tissues. We utilized a physical model of printed spiral coil and applied our algorithm to design PSC operating at 13.56 MHz. Numerical and electromagnetic simulation of power transfer efficiency of PSC in air medium is 77.5% and 71.1%, respectively. The simulation results show that the printed spiral coil which is optimized for air will keep 15.2% power transfer efficiency in human subcutaneous tissues. In addition, the Specific Absorption Ratio (SAR) for this coil antenna in subcutaneous at 13.56 MHz is below 1.6 W/Kg, which suggests this coil is implantable safe based on IEEE C95.1 safety guideline.

Formation of silicon nanocrystals in sapphire by ion implantation and the origin of visible photoluminescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yerci, S.; Serincan, U.; Dogan, I.

2006-10-01

Silicon nanocrystals, average sizes ranging between 3 and 7 nm, were formed in sapphire matrix by ion implantation and subsequent annealing. Evolution of the nanocrystals was detected by Raman spectroscopy and x-ray diffraction (XRD). Raman spectra display that clusters in the matrix start to form nanocrystalline structures at annealing temperatures as low as 800 deg. C in samples with high dose Si implantation. The onset temperature of crystallization increases with decreasing dose. Raman spectroscopy and XRD reveal gradual transformation of Si clusters into crystalline form. Visible photoluminescence band appears following implantation and its intensity increases with subsequent annealing process. Whilemore » the center of the peak does not shift, the intensity of the peak decreases with increasing dose. The origin of the observed photoluminescence is discussed in terms of radiation induced defects in the sapphire matrix.« less

Monte Carlo calculated TG-60 dosimetry parameters for the {beta}{sup -} emitter {sup 153}Sm brachytherapy source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadeghi, Mahdi; Taghdiri, Fatemeh; Hamed Hosseini, S.

Purpose: The formalism recommended by Task Group 60 (TG-60) of the American Association of Physicists in Medicine (AAPM) is applicable for {beta} sources. Radioactive biocompatible and biodegradable {sup 153}Sm glass seed without encapsulation is a {beta}{sup -} emitter radionuclide with a short half-life and delivers a high dose rate to the tumor in the millimeter range. This study presents the results of Monte Carlo calculations of the dosimetric parameters for the {sup 153}Sm brachytherapy source. Methods: Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate two-dimensional dose distributions around the source. The dosimetric parameters ofmore » AAPM TG-60 recommendations including the reference dose rate, the radial dose function, the anisotropy function, and the one-dimensional anisotropy function were obtained. Results: The dose rate value at the reference point was estimated to be 9.21{+-}0.6 cGy h{sup -1} {mu}Ci{sup -1}. Due to the low energy beta emitted from {sup 153}Sm sources, the dose fall-off profile is sharper than the other beta emitter sources. The calculated dosimetric parameters in this study are compared to several beta and photon emitting seeds. Conclusions: The results show the advantage of the {sup 153}Sm source in comparison with the other sources because of the rapid dose fall-off of beta ray and high dose rate at the short distances of the seed. The results would be helpful in the development of the radioactive implants using {sup 153}Sm seeds for the brachytherapy treatment.« less

Evaluation of lattice displacement in Mg - Implanted GaN by Rutherford backscattering spectroscopy

NASA Astrophysics Data System (ADS)

Nishikata, N.; Kushida, K.; Nishimura, T.; Mishima, T.; Kuriyama, K.; Nakamura, T.

2017-10-01

Evaluation of lattice displacement in Mg-ion implanted GaN is studied by combining elastic recoil detection analysis (ERDA), Rutherford backscattering spectroscopy (RBS) and Photoluminescence (PL) measurements. Mg-ion implantation into GaN single crystal wafer is performed with energies of 30 keV (ion fluence; 3.5 × 1014 cm-2) and 60 keV (6.5 × 1014 cm-2) at room temperature. The ERDA measurements using the 1.5 MeV helium beam can evaluate hydrogen from the surface to ∼300 nm. The hydrogen concentration for un-implanted and as-implanted GaN is 3.1 × 1014 cm-2 and 6.1 × 1014 cm-2 at around 265 nm in depth. χmin (the ratio of aligned and random yields) near the surface of the 〈0 0 0 1〉 direction for Ga is 1.61% for un-implanted and 2.51% for Mg-ion implanted samples. On the other hand, the value of χmin for N is 10.08% for un-implanted and 11.20% for Mg-ion implanted samples. The displacement concentration of Ga and N estimated from these χmin values is 4.01 × 1020 cm-3 and 5.46 × 1020 cm-3, respectively. This suggests that Ga vacancy (VGa), N vacancy (VN), Ga interstitial (Gai), and N interstitial (Ni) is introduced in Mg-ion implanted GaN. A strong emission at around 400 nm in as-implanted GaN is related to a VN donor and some acceptor pairs. It is suggested that the origin of the very high resistivity after the Mg-ion implantation is attributed to the carrier compensation effect due to the deep level of Ni as a non-radiative center.

Mastectomy Skin Necrosis After Breast Reconstruction: A Comparative Analysis Between Autologous Reconstruction and Implant-Based Reconstruction.

PubMed

Sue, Gloria R; Lee, Gordon K

2018-05-01

Mastectomy skin necrosis is a significant problem after breast reconstruction. We sought to perform a comparative analysis on this complication between patients undergoing autologous breast reconstruction and patients undergoing 2-stage expander implant breast reconstruction. A retrospective review was performed on consecutive patients undergoing autologous breast reconstruction or 2-stage expander implant breast reconstruction by the senior author from 2006 through 2015. Patient demographic factors including age, body mass index, history of diabetes, history of smoking, and history of radiation to the breast were collected. Our primary outcome measure was mastectomy skin necrosis. Fisher exact test was used for statistical analysis between the 2 patient cohorts. The treatment patterns of mastectomy skin necrosis were then analyzed. We identified 204 patients who underwent autologous breast reconstruction and 293 patients who underwent 2-stage expander implant breast reconstruction. Patients undergoing autologous breast reconstruction were older, heavier, more likely to have diabetes, and more likely to have had prior radiation to the breast compared with patients undergoing implant-based reconstruction. The incidence of mastectomy skin necrosis was 30.4% of patients in the autologous group compared with only 10.6% of patients in the tissue expander group (P < 0.001). The treatment of this complication differed between these 2 patient groups. In general, those with autologous reconstructions were treated with more conservative means. Although 37.1% of patients were treated successfully with local wound care in the autologous group, only 3.2% were treated with local wound care in the tissue expander group (P < 0.001). Less than half (29.0%) of patients in the autologous group were treated with an operative intervention for this complication compared with 41.9% in the implant-based group (P = 0.25). Mastectomy skin necrosis is significantly more likely to occur after autologous breast reconstruction compared with 2-stage expander implant-based breast reconstruction. Patients with autologous reconstructions are more readily treated with local wound care compared with patients with tissue expanders, who tended to require operative treatment of this complication. Patients considering breast reconstruction should be counseled appropriately regarding the differences in incidence and management of mastectomy skin necrosis between the reconstructive options.

Metal elements in tissue with dental peri-implantitis: a pilot study.

PubMed

Fretwurst, Tobias; Buzanich, Guenter; Nahles, Susanne; Woelber, Johan Peter; Riesemeier, Heinrich; Nelson, Katja

2016-09-01

Dental peri-implantitis is characterized by a multifactorial etiology. The role of metal elements as an etiological factor for peri-implantitis is still unclear. The aim of this study was to investigate the incidence of metal elements in bone and mucosal tissues around dental Grade 4 CP titanium implants with signs of peri-implantitis in human patients. In this prospective pilot study, all patients were enrolled consecutively in two study centers. Bone and soft tissue samples of patients with peri-implantitis with indication for explantation were analyzed for the incidence of different elements (Ca, P, Ti, Fe) by means of synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) and polarized light microscopy (PLM). The existence of macrophages and lymphocytes in the histologic specimens was analyzed. Biopsies of 12 patients (seven bone samples, five mucosal samples) were included and analyzed. In nine of the 12 samples (75%), the SRXRF examination revealed the existence of titanium (Ti) and an associated occurrence with Iron (Fe). Metal particles were detected in peri-implant soft tissue using PLM. In samples with increased titanium concentration, lymphocytes were detected, whereas M1 macrophages were predominantly seen in samples with metal particles. Titanium and Iron elements were found in soft and hard tissue biopsies retrieved from peri-implantitis sites. Further histologic and immunohistochemical studies need to clarify which specific immune reaction metal elements/particles induce in dental peri-implant tissue. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Infrared Radiography: Modeling X-ray Imaging Without Harmful Radiation

NASA Astrophysics Data System (ADS)

Zietz, Otto; Mylott, Elliot; Widenhorn, Ralf

2015-01-01

Planar x-ray imaging is a ubiquitous diagnostic tool and is routinely performed to diagnose conditions as varied as bone fractures and pneumonia. The underlying principle is that the varying attenuation coefficients of air, water, tissue, bone, or metal implants within the body result in non-uniform transmission of x-ray radiation. Through the detection of transmitted radiation, the spatial organization and composition of materials in the body can be ascertained. In this paper, we describe an original apparatus that teaches these concepts by utilizing near infrared radiation and an up-converting phosphorescent screen to safely probe the contents of an opaque enclosure.

Sick sinus syndrome as a complication of mediastinal radiation therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pohjola-Sintonen, S.; Toetterman, K.J.K.; Kupari, M.

1990-06-01

A 33-year-old man who had received mediastinal radiation therapy for Hodgkin's disease 12 years earlier developed a symptomatic sick sinus syndrome requiring the implantation of a permanent pacemaker. The sick sinus syndrome and a finding of an occult constrictive pericarditis were considered to be due to the previous mediastinal irradiation. A ventricular pacemaker was chosen because mediastinal radiotherapy also increases the risk of developing atrioventricular conduction defects.

Aortobronchial fistula caused by an endobronchial lobar Y stent: a word of caution.

PubMed

Härting, Margarete; Welter, Stefan; Aigner, Clemens

2018-04-25

A 17-year-old female patient with a history of pulmonary tuberculosis was admitted with progressive dyspnoea and haemoptysis. Five months prior to admission, a left bronchial carina Y stent was implanted. Because of the already destroyed parenchyma, a pneumonectomy was planned. Intraoperatively, an aortobronchial fistula was discovered as the source of bleeding, which could be stopped by pledget-armed sutures. The formation of an aortobronchial fistula has to be considered as a potential source of endobronchial bleeding after stent implantation.

PFC knee replacement: osteolytic failures from extreme polyethylene degradation.

PubMed

Casey, David; Cottrell, Jocelyn; DiCarlo, Edward; Windsor, Russell; Wright, Timothy

2007-11-01

Despite the long-term success of press-fit condylar (PFC) knee prostheses, premature failures caused by aggressive rapid osteolysis have been reported. To investigate why patients experience such failures, we reviewed 48 retrieved implants and surrounding tissues together with demographic and radiographic data. Polyethylene degradation was determined from density profiles taken through the retrieved inserts. We compared the histology of tissues around PFC implants with that from around failed implants of similar designs from patients matched to length of implantation, body mass index, and age. The pathologic response in PFC patients showed more widespread, dense, sheet-like cellular infiltrate, whereas in the matched patients, the infiltrate was generally scattered discontinuously. The dominant wear mode of the PFC inserts was severe delamination on the articular surfaces. Wear damage was worse with increased length of implantation and was correlated with oxidative degradation and osteolysis. Degradation and osteolysis were more severe with inserts stored longer and sterilized by gamma radiation in air. These results underscore that degradation and increased shelf life lead to osteolysis and loosening. However, they raise questions concerning the cellular reaction to the debris from PFC implants that could lead to a better general understanding of osteolysis.

Cadaveric verification of the Eclipse AAA algorithm for spine SBRT treatments with titanium hardware.

PubMed

Grams, Michael P; Fong de Los Santos, Luis E; Antolak, John A; Brinkmann, Debra H; Clarke, Michelle J; Park, Sean S; Olivier, Kenneth R; Whitaker, Thomas J

2016-01-01

To assess the accuracy of the Eclipse Analytical Anisotropic Algorithm when calculating dose for spine stereotactic body radiation therapy treatments involving surgically implanted titanium hardware. A human spine was removed from a cadaver, cut sagittally along the midline, and then separated into thoracic and lumbar sections. The thoracic section was implanted with titanium stabilization hardware; the lumbar section was not implanted. Spine sections were secured in a water phantom and simulated for treatment planning using both standard and extended computed tomography (CT) scales. Target volumes were created on both spine sections. Dose calculations were performed using (1) the standard CT scale with relative electron density (RED) override of image artifacts and hardware, (2) the extended CT scale with RED override of image artifacts only, and (3) the standard CT scale with no RED overrides for hardware or artifacts. Plans were delivered with volumetric modulated arc therapy using a 6-MV beam with and without a flattening filter. A total of 3 measurements for each plan were made with Gafchromic film placed between the spine sections and compared with Eclipse dose calculations using gamma analysis with a 2%/2 mm passing criteria. A single measurement in a homogeneous phantom was made for each plan before actual delivery. Gamma passing rates for measurements in the homogeneous phantom were 99.6% or greater. Passing rates for measurements made in the lumbar spine section without hardware were 99.3% or greater; measurements made in the thoracic spine containing titanium were 98.6 to 99.5%. Eclipse Analytical Anisotropic Algorithm can adequately model the effects of titanium implants for spine stereotactic body radiation therapy treatments using volumetric modulated arc therapy. Calculations with standard or extended CT scales give similarly accurate results. Copyright © 2016 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

SU-E-T-609: Perturbation Effects of Pedicle Screws On Radiotherapy Dose Distributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bar-Deroma, R; Borzov, E; Nevelsky, A

2015-06-15

Purpose: Radiation therapy in conjunction with surgical implant fixation is a common combined treatment in case of bone metastases. However, metal implants generally used in orthopedic implants perturb radiation dose distributions. Carbon-Fiber Reinforced (CFR) PEEK material has been recently introduced for production of intramedullary screws and plates. Gold powder can be added to the CFR-PEEK material in order to enhance visibility of the screws during intraoperative imaging procedures. In this work, we investigated the perturbation effects of the pedicle screws made of CFR-PEEK, CFR-PEEK with added gold powder (CFR-PEEK-AU) and Titanium (Ti) on radiotherapy dose distributions. Methods: Monte Carlo (MC)more » simulations were performed using the EGSnrc code package for 6MV beams with 10×10 fields at SSD=100cm. By means of MC simulations, dose distributions around titanium, CFR- PEEK and CFR-PEEK-AU screws (manufactured by Carbo-Fix Orthopedics LTD, Israel) placed in a water phantom were calculated. The screw axis was either parallel or perpendicular to the beam axis. Dose perturbation (relative to dose in homogeneous water phantom) was assessed. Results: Maximum overdose due to backscatter was 10% for the Ti screws, 5% for the CFR-PEEK-AU screws and effectively zero for the CFR-PEEK screws. Maximum underdose due to attenuation was 25% for the Ti screws, 15% for the CFR-PEEK-AU screws and 5% for the CFR-PEEK screws. Conclusion: Titanium screws introduce the largest distortion on the radiation dose distribution. The gold powder added to the CFR-PEEK material improves visibility at the cost of increased dose perturbation. CFR-PEEK screws caused minimal alteration on the dose distribution. This can decrease possible over and underdose of adjacent tissue and thus favorably influence treatment efficiency. The use of such implants has potential clinical advantage in the treatment of neoplastic bone disease.« less

Investigation of the Structural Stability of Ion-Implanted Gd 2Ti 2-xSn xO 7 Pyrochlore-Type Oxides by Glancing Angle X-ray Absorption Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aluri, Esther Rani; Hayes, John R.; Walker, James D.S.

2016-03-24

Rare-earth titanate and stannate pyrochlore-type oxides have been investigated in the past for the sequestration of nuclear waste elements because of their resistance to radiation-induced structural damage. In order to enhance this property, it is necessary to understand the effect of radioactive decay of the incorporated actinide elements on the local chemical environment. In this study, Gd 2Ti 2–xSn xO 7 materials have been implanted with Au– ions to simulate radiation-induced structural damage. Glancing angle X-ray absorption near-edge spectroscopy (GA-XANES), glancing angle X-ray absorption fine structure (GA-EXAFS) analysis, and powder X-ray diffraction have been used to investigate changes in themore » local coordination environment of the metal atoms in the damaged surface layer. Examination of GA-XANES/EXAFS spectra from the implanted Gd 2Ti 2–xSn xO 7 materials collected at various glancing angles allowed for an investigation of how the local coordination environment around the absorbing atoms changed at different depths in the damaged surface layer. This study has shown the usefulness of GA-XANES to the examination of ion-implanted materials and has suggested that Gd 2Ti 2–xSn xO 7 becomes more susceptible to ion-beam-induced structural damage with increasing Sn concentration.« less

Applications of high-energy heavy-ions from superconducting cyclotrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grimm, T. L.

1999-06-10

The superconducting cyclotrons of the National Superconducting Cyclotron Laboratory (NSCL), a major nuclear physics facility, can provide ions of any element from hydrogen to uranium. A major upgrade to the NSCL is underway and will consist of an electron cyclotron resonance (ECR) ion source followed by two large superconducting cyclotrons (K500 and K1200). Ions can be extracted at any point along this chain allowing a large range of energies and charge states. The ion energies range from a few keV to over 20 GeV, and charge states up to fully stripped {sup 197}Au{sup 79+} and two electron {sup 238}U{sup 90+}more » are possible. The long range of the high-energy heavy-ions allows them to penetrate deeply into a target that is placed in air, outside a vacuum chamber. The ion beams have already been used for a number of applications including; ion implantation, atomic physics, single event effects in integrated circuits, DNA radiation studies, radiation detector studies, flux pinning in high-T{sub c} superconductors, calibration of a space-based spectrometer, isotropic ratio measurements, material wear studies, and continuous positron emission tomography imaging.« less

Impurity-defect complexes in non-implanted aluminum

NASA Astrophysics Data System (ADS)

Pedersen, F. T.; Grann, H.; Weyer, G.

1986-02-01

The formation of impurity-defect complexes in ion-implanted aluminum has been studied in the temperature interval 100 400K. Radioactive119In isotopes have been implanted. Mössbauer spectra have been measured for the 24 keV γ-radiation emitted after the decay to119Sn. The spectra could be analysed satisfactorily with two lines, one of which is known to be due to substitutional Sn. A second line, which has a higher isomer shift and lower Debye temperature, is tentatively assigned to vacancy-associated Sn, formed by trapping of thermally mobile (multi-)vacancies. Comparison to similar DPAC experiments suggests that cubic Sn-V4 complexes are formed. Some indication (˜15%) for an athermal formation of impurity defects below 175K is obtained.

Sapphire implant based neuro-complex for deep-lying brain tumors phototheranostics

NASA Astrophysics Data System (ADS)

Sharova, A. S.; Maklygina, YU S.; Yusubalieva, G. M.; Shikunova, I. A.; Kurlov, V. N.; Loschenov, V. B.

2018-01-01

The neuro-complex as a combination of sapphire implant optical port and osteoplastic biomaterial "Collapan" as an Aluminum phthalocyanine nanoform photosensitizer (PS) depot was developed within the framework of this study. The main goals of such neuro-complex are to provide direct access of laser radiation to the brain tissue depth and to transfer PS directly to the pathological tissue location that will allow multiple optical phototheranostics of the deep-lying tumor region without repeated surgical intervention. The developed complex spectral-optical properties research was carried out by photodiagnostics method using the model sample: a brain tissue phantom. The optical transparency of sapphire implant allows obtaining a fluorescent signal with high accuracy, comparable to direct measurement "in contact" with the tissue.

Financial Impact of Dual Vendor, Matrix Pricing, and Sole-Source Contracting on Implant Costs.

PubMed

Althausen, Peter L; Lapham, Joan; Mead, Lisa

2016-12-01

Implant costs comprise the largest proportion of operating room supply costs for orthopedic trauma care. Over the years, hospitals have devised several methods of controlling these costs with the help of physicians. With increasing economic pressure, these negotiations have a tremendous ability to decrease the cost of trauma care. In the past, physicians have taken no responsibility for implant pricing which has made cost control difficult. The reasons have been multifactorial. However, industry surgeon consulting fees, research support, and surgeon comfort with certain implant systems have played a large role in slowing adoption of cost-control measures. With the advent of physician gainsharing and comanagement agreements, physicians now have impetus to change. At our facility, we have used 3 methods for cost containment since 2009: dual vendor, matrix pricing, and sole-source contracting. Each has been increasingly successful, resulting in massive savings for the institution. This article describes the process and benefits of each model.

Biocompatible ionic liquid-biopolymer electrolyte-enabled thin and compact magnesium-air batteries.

PubMed

Jia, Xiaoteng; Yang, Yang; Wang, Caiyun; Zhao, Chen; Vijayaraghavan, R; MacFarlane, Douglas R; Forsyth, Maria; Wallace, Gordon G

2014-12-10

With the surge of interest in miniaturized implanted medical devices (IMDs), implantable power sources with small dimensions and biocompatibility are in high demand. Implanted battery/supercapacitor devices are commonly packaged within a case that occupies a large volume, making miniaturization difficult. In this study, we demonstrate a polymer electrolyte-enabled biocompatible magnesium-air battery device with a total thickness of approximately 300 μm. It consists of a biocompatible polypyrrole-para(toluene sulfonic acid) cathode and a bioresorbable magnesium alloy anode. The biocompatible electrolyte used is made of choline nitrate (ionic liquid) embedded in a biopolymer, chitosan. This polymer electrolyte is mechanically robust and offers a high ionic conductivity of 8.9 × 10(-3) S cm(-1). The assembled battery delivers a maximum volumetric power density of 3.9 W L(-1), which is sufficient to drive some types of IMDs, such as cardiac pacemakers or biomonitoring systems. This miniaturized, biocompatible magnesium-air battery may pave the way to a future generation of implantable power sources.

Relationship between sponsorship and failure rate of dental implants: a systematic approach.

PubMed

Popelut, Antoine; Valet, Fabien; Fromentin, Olivier; Thomas, Aurélie; Bouchard, Philippe

2010-04-21

The number of dental implant treatments increases annually. Dental implants are manufactured by competing companies. Systematic reviews and meta-analysis have shown a clear association between pharmaceutical industry funding of clinical trials and pro-industry results. So far, the impact of industry sponsorship on the outcomes and conclusions of dental implant clinical trials has never been explored. The aim of the present study was to examine financial sponsorship of dental implant trials, and to evaluate whether research funding sources may affect the annual failure rate. A systematic approach was used to identify systematic reviews published between January 1993 and December 2008 that specifically deal with the length of survival of dental implants. Primary articles were extracted from these reviews. The failure rate of the dental implants included in the trials was calculated. Data on publication year, Impact Factor, prosthetic design, periodontal status reporting, number of dental implants included in the trials, methodological quality of the studies, presence of a statistical advisor, and financial sponsorship were extracted by two independent reviewers (kappa = 0.90; CI(95%) [0.77-1.00]). Univariate quasi-Poisson regression models and multivariate analysis were used to identify variables that were significantly associated with failure rates. Five systematic reviews were identified from which 41 analyzable trials were extracted. The mean annual failure rate estimate was 1.09%.(CI(95%) [0.84-1.42]). The funding source was not reported in 63% of the trials (26/41). Sixty-six percent of the trials were considered as having a risk of bias (27/41). Given study age, both industry associated (OR = 0.21; CI(95%) [0.12-0.38]) and unknown funding source trials (OR = 0.33; (CI(95%) [0.21-0.51]) had a lower annual failure rates compared with non-industry associated trials. A conflict of interest statement was disclosed in 2 trials. When controlling for other factors, the probability of annual failure for industry associated trials is significantly lower compared with non-industry associated trials. This bias may have significant implications on tooth extraction decision making, research on tooth preservation, and governmental health care policies.

Potential biomedical applications of ion beam technology

NASA Technical Reports Server (NTRS)

Banks, B. A.; Weigand, A. J.; Babbush, C. A.; Vankampen, C. L.

1976-01-01

Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic pros-thesis fixtion, and dental implants.

Potential biomedical applications of ion beam technology

NASA Technical Reports Server (NTRS)

Banks, B. A.; Weigand, A. J.; Van Kampen, C. L.; Babbush, C. A.

1976-01-01

Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic prosthesis fixation, and dental implants.

Assessment of thermal effects in a model of the human head implanted with a wireless active microvalve for the treatment of glaucoma creating a filtering bleb

NASA Astrophysics Data System (ADS)

Schaumburg, F.; Guarnieri, F. A.

2017-05-01

A 3D anatomical computational model is developed to assess thermal effects due to exposure to the electromagnetic field required to power a new investigational active implantable microvalve for the treatment of glaucoma. Such a device, located in the temporal superior eye quadrant, produces a filtering bleb, which is included in the geometry of the model, together with the relevant ocular structures. The electromagnetic field source—a planar coil—as well as the microvalve antenna and casing are also included. Exposure to the electromagnetic field source of an implanted and a non-implanted subject are simulated by solving a magnetic potential formulation, using the finite element method. The maximum SAR10 is reached in the eyebrow and remains within the limits suggested by the IEEE and ICNIRP standards. The anterior chamber, filtering bleb, iris and ciliary body are the ocular structures where more absorption occurs. The temperature rise distribution is also obtained by solving the bioheat equation with the finite element method. The numerical results are compared with the in vivo measurements obtained from four rabbits implanted with the microvalve and exposed to the electromagnetic field source.

MRI evaluation of post-mastectomy irradiated breast implants: prevalence and analysis of complications.

PubMed

Rella, L; Telegrafo, M; Nardone, A; Milella, A; Stabile Ianora, A A; Lioce, M; Angelelli, G; Moschetta, M

2015-09-01

To evaluate the effect of post-mastectomy radiation therapy (RT) on breast implants as detected by magnetic resonance imaging (MRI) searching for short-term complications. One hundred and forty patients (total of 144 implants) were evaluated by MRI; 80 (group 1) had undergone RT, whereas the remaining 60 patients (group 2) underwent mastectomy with implant reconstruction without RT. Two radiologists evaluated MRI images searching for implant rupture signs, sub-capsular seromas, capsular contracture, soft-tissue oedema, peri-implant fluid collections. Implant ruptures were classified as severe complications; seromas and capsular contractures as moderate complications; oedema and fluid collections as mild complications. The prevalence of MRI findings in the two groups was calculated and compared by unpaired t-test. Cohen's kappa statistics was used to assess interobserver agreement. Sixty-nine out of 144 (48%) implants presented pathological findings at MRI with complication rates of 47.5 and 48.4 for groups 1 and 2, respectively. Two (5%) severe complications, 10 (26%) moderate complications, and 26 (69%) mild complications occurred in group 1 and surgical treatment was performed in 10 cases. Two (6%) severe complications, seven (23%) moderate complications, and 22 (71%) mild complications occurred in group 2 and surgical treatment was performed in eight cases. No significant difference between the two groups was found (p>0.1). Almost perfect agreement between the two radiologists was found for MRI image detection (k=0.86). RT does not seem to cause a significant effect on breast implants in terms of complication rate in patients undergoing implant-based breast reconstruction. One-stage immediate implant-based breast reconstruction performed at the same time as mastectomy could be proposed. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Analysis of induced electrical currents from magnetic field coupling inside implantable neurostimulator leads.

PubMed

Pantchenko, Oxana S; Seidman, Seth J; Guag, Joshua W

2011-10-21

Over the last decade, the number of neurostimulator systems implanted in patients has been rapidly growing. Nearly 50, 000 neurostimulators are implanted worldwide annually. The most common type of implantable neurostimulators is indicated for pain relief. At the same time, commercial use of other electromagnetic technologies is expanding, making electromagnetic interference (EMI) of neurostimulator function an issue of concern. Typically reported sources of neurostimulator EMI include security systems, metal detectors and wireless equipment. When near such sources, patients with implanted neurostimulators have reported adverse events such as shock, pain, and increased stimulation. In recent in vitro studies, radio frequency identification (RFID) technology has been shown to inhibit the stimulation pulse of an implantable neurostimulator system during low frequency exposure at close distances. This could potentially be due to induced electrical currents inside the implantable neurostimulator leads that are caused by magnetic field coupling from the low frequency identification system. To systematically address the concerns posed by EMI, we developed a test platform to assess the interference from coupled magnetic fields on implantable neurostimulator systems. To measure interference, we recorded the output of one implantable neurostimulator, programmed for best therapy threshold settings, when in close proximity to an operating low frequency RFID emitter. The output contained electrical potentials from the neurostimulator system and those induced by EMI from the RFID emitter. We also recorded the output of the same neurostimulator system programmed for best therapy threshold settings without RFID interference. Using the Spatially Extended Nonlinear Node (SENN) model, we compared threshold factors of spinal cord fiber excitation for both recorded outputs. The electric current induced by low frequency RFID emitter was not significant to have a noticeable effect on electrical stimulation. We demonstrated a method for analyzing effects of coupled magnetic field interference on implantable neurostimulator system and its electrodes which could be used by device manufacturers during the design and testing phases of the development process.

Analysis of induced electrical currents from magnetic field coupling inside implantable neurostimulator leads

PubMed Central

2011-01-01

Background Over the last decade, the number of neurostimulator systems implanted in patients has been rapidly growing. Nearly 50, 000 neurostimulators are implanted worldwide annually. The most common type of implantable neurostimulators is indicated for pain relief. At the same time, commercial use of other electromagnetic technologies is expanding, making electromagnetic interference (EMI) of neurostimulator function an issue of concern. Typically reported sources of neurostimulator EMI include security systems, metal detectors and wireless equipment. When near such sources, patients with implanted neurostimulators have reported adverse events such as shock, pain, and increased stimulation. In recent in vitro studies, radio frequency identification (RFID) technology has been shown to inhibit the stimulation pulse of an implantable neurostimulator system during low frequency exposure at close distances. This could potentially be due to induced electrical currents inside the implantable neurostimulator leads that are caused by magnetic field coupling from the low frequency identification system. Methods To systematically address the concerns posed by EMI, we developed a test platform to assess the interference from coupled magnetic fields on implantable neurostimulator systems. To measure interference, we recorded the output of one implantable neurostimulator, programmed for best therapy threshold settings, when in close proximity to an operating low frequency RFID emitter. The output contained electrical potentials from the neurostimulator system and those induced by EMI from the RFID emitter. We also recorded the output of the same neurostimulator system programmed for best therapy threshold settings without RFID interference. Using the Spatially Extended Nonlinear Node (SENN) model, we compared threshold factors of spinal cord fiber excitation for both recorded outputs. Results The electric current induced by low frequency RFID emitter was not significant to have a noticeable effect on electrical stimulation. Conclusions We demonstrated a method for analyzing effects of coupled magnetic field interference on implantable neurostimulator system and its electrodes which could be used by device manufacturers during the design and testing phases of the development process. PMID:22014169

Radiation Damage Workshop

NASA Technical Reports Server (NTRS)

Stella, P. M.

1984-01-01

The availability of data regarding the radiation behavior of GaAs and silicon solar cells is discussed as well as efforts to provide sufficient information. Other materials are considered too immature for reasonable radiation evaluation. The lack of concern over the possible catastrophic radiation degradation in cascade cells is a potentially serious problem. Lithium counterdoping shows potential for removing damage in irradiated P-type material, although initial efficiencies are not comparable to current state of the art. The possibility of refining the lithium doping method to maintain high initial efficiencies and combining it with radiation tolerant structures such as thin BSF cells or vertical junction cells could provide a substantial improvement in EOL efficiencies. Laser annealing of junctions, either those formed ion implantation or diffusion, may not only improve initial cell performance but might also reduce the radiation degradation rate.

Multiple layer optical memory system using second-harmonic-generation readout

DOEpatents

Boyd, Gary T.; Shen, Yuen-Ron

1989-01-01

A novel optical read and write information storage system is described which comprises a radiation source such as a laser for writing and illumination, the radiation source being capable of radiating a preselected first frequency; a storage medium including at least one layer of material for receiving radiation from the radiation source and capable of being surface modified in response to said radiation source when operated in a writing mode and capable of generating a pattern of radiation of the second harmonic of the preselected frequency when illuminated by the radiation source at the preselected frequency corresponding to the surface modifications on the storage medium; and a detector to receive the pattern of second harmonic frequency generated.

Brachytherapy optimization using radiobiological-based planning for high dose rate and permanent implants for prostate cancer treatment

NASA Astrophysics Data System (ADS)

Seeley, Kaelyn; Cunha, J. Adam; Hong, Tae Min

2017-01-01

We discuss an improvement in brachytherapy--a prostate cancer treatment method that directly places radioactive seeds inside target cancerous regions--by optimizing the current standard for delivering dose. Currently, the seeds' spatiotemporal placement is determined by optimizing the dose based on a set of physical, user-defined constraints. One particular approach is the ``inverse planning'' algorithms that allow for tightly fit isodose lines around the target volumes in order to reduce dose to the patient's organs at risk. However, these dose distributions are typically computed assuming the same biological response to radiation for different types of tissues. In our work, we consider radiobiological parameters to account for the differences in the individual sensitivities and responses to radiation for tissues surrounding the target. Among the benefits are a more accurate toxicity rate and more coverage to target regions for planning high-dose-rate treatments as well as permanent implants.

Dynamic defect annealing in wurtzite MgZnO implanted with Ar ions

NASA Astrophysics Data System (ADS)

Azarov, A. Yu.; Wendler, E.; Du, X. L.; Kuznetsov, A. Yu.; Svensson, B. G.

2015-09-01

Successful implementation of ion beams for modification of ternary ZnO-based oxides requires understanding and control of radiation-induced defects. Here, we study structural disorder in wurtzite ZnO and MgxZn1-xO (x ⩽ 0.3) samples implanted at room and 15 K temperatures with Ar ions in a wide fluence range (5 × 1012-3 × 1016 cm-2). The samples were characterized by Rutherford backscattering/channeling spectrometry performed in-situ without changing the sample temperature. The results show that all the samples exhibit high radiation resistance and cannot be rendered amorphous even for high ion fluences. Increasing the Mg content leads to some damage enhancement near the surface region; however, irrespective of the Mg content, the fluence dependence of bulk damage in the samples displays the so-called IV-stage evolution with a reverse temperature effect for high ion fluences.

Three-dimensional noninvasive monitoring iodine-131 uptake in the thyroid using a modified Cerenkov luminescence tomography approach.

PubMed

Hu, Zhenhua; Ma, Xiaowei; Qu, Xiaochao; Yang, Weidong; Liang, Jimin; Wang, Jing; Tian, Jie

2012-01-01

Cerenkov luminescence tomography (CLT) provides the three-dimensional (3D) radiopharmaceutical biodistribution in small living animals, which is vital to biomedical imaging. However, existing single-spectral and multispectral methods are not very efficient and effective at reconstructing the distribution of the radionuclide tracer. In this paper, we present a semi-quantitative Cerenkov radiation spectral characteristic-based source reconstruction method named the hybrid spectral CLT, to efficiently reconstruct the radionuclide tracer with both encouraging reconstruction results and less acquisition and image reconstruction time. We constructed the implantation mouse model implanted with a 400 µCi Na(131)I radioactive source and the physiological mouse model received an intravenous tail injection of 400 µCi radiopharmaceutical Iodine-131 (I-131) to validate the performance of the hybrid spectral CLT and compared the reconstruction results, acquisition, and image reconstruction time with that of single-spectral and multispectral CLT. Furthermore, we performed 3D noninvasive monitoring of I-131 uptake in the thyroid and quantified I-131 uptake in vivo using hybrid spectral CLT. Results showed that the reconstruction based on the hybrid spectral CLT was more accurate in localization and quantification than using single-spectral CLT, and was more efficient in the in vivo experiment compared with multispectral CLT. Additionally, 3D visualization of longitudinal observations suggested that the reconstructed energy of I-131 uptake in the thyroid increased with acquisition time and there was a robust correlation between the reconstructed energy versus the gamma ray counts of I-131 (r(2) = 0.8240). The ex vivo biodistribution experiment further confirmed the I-131 uptake in the thyroid for hybrid spectral CLT. Results indicated that hybrid spectral CLT could be potentially used for thyroid imaging to evaluate its function and monitor its treatment for thyroid cancer.

Fabrication of a Cryogenic Terahertz Emitter for Bolometer Focal Plane Calibrations

NASA Technical Reports Server (NTRS)

Chervenak, James; Brown, Ari; Wollack, Edward

2012-01-01

A fabrication process is reported for prototype emitters of THz radiation, which operate cryogenically, and should provide a fast, stable blackbody source suitable for characterization of THz devices. The fabrication has been demonstrated and, at the time of this reporting, testing was underway. The emitter is similar to a monolithic silicon bolometer in design, using both a low-noise thermometer and a heater element on a thermally isolated stage. An impedance-matched, high-emissivity coat ing is also integrated to tune the blackbody properties. This emitter is designed to emit a precise amount of power as a blackbody spectrum centered on terahertz frequencies. The emission is a function of the blackbody temperature. An integrated resistive heater and thermometer system can control the temperature of the blackbody with greater precision than previous incarnations of calibration sources that relied on blackbody emission. The emitter is fabricated using a silicon- on-insulator substrate wafer. The buried oxide is chosen to be less than 1 micron thick, and the silicon device thickness is 1-2 microns. Layers of phosphorus compensated with boron are implanted into and diffused throughout the full thickness of the silicon device layer to create the thermometer and heater components. Degenerately doped wiring is implanted to connect the devices to wire-bondable contact pads at the edge of the emitter chip. Then the device is micromachined to remove the thick-handle silicon behind the thermometer and heater components, and to thermally isolate it on a silicon membrane. An impedance- matched emissive coating (ion assisted evaporated Bi) is applied to the back of the membrane to enable high-efficiency emission of the blackbody spectrum.

75 FR 69591 - Medicaid Program; Withdrawal of Determination of Average Manufacturer Price, Multiple Source Drug...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-15

... issue a proposed regulation addressing the Affordable Care Act provisions. Inhalation, Infusion..., infusion, instilled, implanted and injectable drugs that are not generally dispensed through retail... publish a list of drugs that meet the statutory definition of inhalation, infusion, instilled, implanted...

Porcelain-coated antenna for radio-frequency driven plasma source

DOEpatents

Leung, Ka-Ngo; Wells, Russell P.; Craven, Glen E.

1996-01-01

A new porcelain-enamel coated antenna creates a clean plasma for volume or surface-conversion ion sources. The porcelain-enamel coating is hard, electrically insulating, long lasting, non fragile, and resistant to puncture by high energy ions in the plasma. Plasma and ion production using the porcelain enamel coated antenna is uncontaminated with filament or extraneous metal ion because the porcelain does not evaporate and is not sputtered into the plasma during operation. Ion beams produced using the new porcelain-enamel coated antenna are useful in ion implantation, high energy accelerators, negative, positive, or neutral beam applications, fusion, and treatment of chemical or radioactive waste for disposal. For ion implantation, the appropriate species ion beam generated with the inventive antenna will penetrate large or small, irregularly shaped conducting objects with a narrow implantation profile.

Single-Sided Deafness: Impact of Cochlear Implantation on Speech Perception in Complex Noise and on Auditory Localization Accuracy.

PubMed

Döge, Julia; Baumann, Uwe; Weissgerber, Tobias; Rader, Tobias

2017-12-01

To assess auditory localization accuracy and speech reception threshold (SRT) in complex noise conditions in adult patients with acquired single-sided deafness, after intervention with a cochlear implant (CI) in the deaf ear. Nonrandomized, open, prospective patient series. Tertiary referral university hospital. Eleven patients with late-onset single-sided deafness (SSD) and normal hearing in the unaffected ear, who received a CI. All patients were experienced CI users. Unilateral cochlear implantation. Speech perception was tested in a complex multitalker equivalent noise field consisting of multiple sound sources. Speech reception thresholds in noise were determined in aided (with CI) and unaided conditions. Localization accuracy was assessed in complete darkness. Acoustic stimuli were radiated by multiple loudspeakers distributed in the frontal horizontal plane between -60 and +60 degrees. In the aided condition, results show slightly improved speech reception scores compared with the unaided condition in most of the patients. For 8 of the 11 subjects, SRT was improved between 0.37 and 1.70 dB. Three of the 11 subjects showed deteriorations between 1.22 and 3.24 dB SRT. Median localization error decreased significantly by 12.9 degrees compared with the unaided condition. CI in single-sided deafness is an effective treatment to improve the auditory localization accuracy. Speech reception in complex noise conditions is improved to a lesser extent in 73% of the participating CI SSD patients. However, the absence of true binaural interaction effects (summation, squelch) impedes further improvements. The development of speech processing strategies that respect binaural interaction seems to be mandatory to advance speech perception in demanding listening situations in SSD patients.

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

Surface Passivation and Junction Formation Using Low Energy Hydrogen Implants

NASA Technical Reports Server (NTRS)

Fonash, S. J.

1985-01-01

New applications for high current, low energy hydrogen ion implants on single crystal and polycrystal silicon grain boundaries are discussed. The effects of low energy hydrogen ion beams on crystalline Si surfaces are considered. The effect of these beams on bulk defects in crystalline Si is addressed. Specific applications of H+ implants to crystalline Si processing are discussed. In all of the situations reported on, the hydrogen beams were produced using a high current Kaufman ion source.

Breaking the sound barrier: exploring parents' decision-making process of cochlear implants for their children.

PubMed

Chang, Pamara F

2017-08-01

To understand the dynamic experiences of parents undergoing the decision-making process regarding cochlear implants for their child(ren). Thirty-three parents of d/Deaf children participated in semi-structured interviews. Interviews were digitally recorded, transcribed, and coded using iterative and thematic coding. The results from this study reveal four salient topics related to parents' decision-making process regarding cochlear implantation: 1) factors parents considered when making the decision to get the cochlear implant for their child (e.g., desire to acculturate child into one community), 2) the extent to which parents' communities influence their decision-making (e.g., norms), 3) information sources parents seek and value when decision-making (e.g., parents value other parent's experiences the most compared to medical or online sources), and 4) personal experiences with stigma affecting their decision to not get the cochlear implant for their child. This study provides insights into values and perspectives that can be utilized to improve informed decision-making, when making risky medical decisions with long-term implications. With thorough information provisions, delineation of addressing parents' concerns and encompassing all aspects of the decision (i.e., medical, social and cultural), health professional teams could reduce the uncertainty and anxiety for parents in this decision-making process for cochlear implantation. Copyright © 2017 Elsevier B.V. All rights reserved.

Cochlear implant microphone location affects speech recognition in diffuse noise.

PubMed

Kolberg, Elizabeth R; Sheffield, Sterling W; Davis, Timothy J; Sunderhaus, Linsey W; Gifford, René H

2015-01-01

Despite improvements in cochlear implants (CIs), CI recipients continue to experience significant communicative difficulty in background noise. Many potential solutions have been proposed to help increase signal-to-noise ratio in noisy environments, including signal processing and external accessories. To date, however, the effect of microphone location on speech recognition in noise has focused primarily on hearing aid users. The purpose of this study was to (1) measure physical output for the T-Mic as compared with the integrated behind-the-ear (BTE) processor mic for various source azimuths, and (2) to investigate the effect of CI processor mic location for speech recognition in semi-diffuse noise with speech originating from various source azimuths as encountered in everyday communicative environments. A repeated-measures, within-participant design was used to compare performance across listening conditions. A total of 11 adults with Advanced Bionics CIs were recruited for this study. Physical acoustic output was measured on a Knowles Experimental Mannequin for Acoustic Research (KEMAR) for the T-Mic and BTE mic, with broadband noise presented at 0 and 90° (directed toward the implant processor). In addition to physical acoustic measurements, we also assessed recognition of sentences constructed by researchers at Texas Instruments, the Massachusetts Institute of Technology, and the Stanford Research Institute (TIMIT sentences) at 60 dBA for speech source azimuths of 0, 90, and 270°. Sentences were presented in a semi-diffuse restaurant noise originating from the R-SPACE 8-loudspeaker array. Signal-to-noise ratio was determined individually to achieve approximately 50% correct in the unilateral implanted listening condition with speech at 0°. Performance was compared across the T-Mic, 50/50, and the integrated BTE processor mic. The integrated BTE mic provided approximately 5 dB attenuation from 1500-4500 Hz for signals presented at 0° as compared with 90° (directed toward the processor). The T-Mic output was essentially equivalent for sources originating from 0 and 90°. Mic location also significantly affected sentence recognition as a function of source azimuth, with the T-Mic yielding the highest performance for speech originating from 0°. These results have clinical implications for (1) future implant processor design with respect to mic location, (2) mic settings for implant recipients, and (3) execution of advanced speech testing in the clinic. American Academy of Audiology.

Quantitative analysis of titanium-induced artifacts and correlated factors during micro-CT scanning.

PubMed

Li, Jun Yuan; Pow, Edmond Ho Nang; Zheng, Li Wu; Ma, Li; Kwong, Dora Lai Wan; Cheung, Lim Kwong

2014-04-01

To investigate the impact of cover screw, resin embedment, and implant angulation on artifact of microcomputed tomography (micro-CT) scanning for implant. A total of twelve implants were randomly divided into 4 groups: (i) implant only; (ii) implant with cover screw; (iii) implant with resin embedment; and (iv) implants with cover screw and resin embedment. Implants angulation at 0°, 45°, and 90° were scanned by micro-CT. Images were assessed, and the ratio of artifact volume to total volume (AV/TV) was calculated. A multiple regression analysis in stepwise model was used to determine the significance of different factors. One-way ANOVA was performed to identify which combination of factors could minimize the artifact. In the regression analysis, implant angulation was identified as the best predictor for artifact among the factors (P < 0.001). Resin embedment also had significant effect on artifact volume (P = 0.028), while cover screw had not (P > 0.05). Non-embedded implants with the axis parallel to X-ray source of micro-CT produced minimal artifact. Implant angulation and resin embedment affected the artifact volume of micro-CT scanning for implant, while cover screw did not. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The impact of overhead lines for employees with stents

NASA Astrophysics Data System (ADS)

Syrek, P.; Skowron, M.

2017-05-01

The aim of article is to discuss interaction between stents implanted in the body of worker and harmonic magnetic field in the vicinity of electric wires. In last decades, a growing proportion of people has any devices implanted, to list: cardiac pacemakers, cardioverter - defibrillators. Recommendations of International Commision on Non-ionizing Radiation Protection (ICNIRP), and resctrictions imposed in different states, may exlude specific individuals from their duties. The autors focused on the situation, when the employee with stent, works in the immediate vicinity of overhead electric wires, cleaning with dry ice the electric insulators.

Estimation of the efficiency of the introduction of a porous layer into a silicon-on-sapphire structure substrate to enhance the reliability of devices under irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aleksandrov, P. A., E-mail: Alexandrov-PA@nrcki.ru; Baranova, E. K.; Budaragin, V. V.

2016-08-15

We investigate the efficiency of the introduction of a porous layer into the substrate of a silicon-onsapphire structure by the implantation of He ions to enhance the radiation resistance of devices. The properties of the introduced layer and its parameters affecting the concentration of minority charge carriers generated by irradiation are analyzed. The reported results of the analysis and calculations can be used to optimize He-ion implantation conditions during the formation of a porous layer.

Structural Changes in Polymer Films by Fast Ion Implantation

NASA Astrophysics Data System (ADS)

Parada, M. A.; Minamisawa, R. A.; Muntele, C.; Muntele, I.; De Almeida, A.; Ila, D.

2006-11-01

In applications from food wrapping to solar sails, polymers films can be subjected to intense charged panicle bombardment and implantation. ETFE (ethylenetetrafluoroethylene) with high impact resistance is used for pumps, valves, tie wraps, and electrical components. PFA (tetrafluoroethylene-per-fluoromethoxyethylene) and FEP (tetrafluoroethylene-hexa-fluoropropylene) are sufficiently biocompatible to be used as transcutaneous implants since they resist damage from the ionizing space radiation, they can be used in aerospace engineering applications. PVDC (polyvinyllidene-chloride) is used for food packaging, and combined with others plastics, improves the oxygen barrier responsible for the food preservation. Fluoropolymers are also known for their radiation dosimetry applications, dependent on the type and energy of the radiation, as well as of the beam intensity. In this work ETFE, PFA, FEP and PVDC were irradiated with ions of keV and MeV energies at several fluences and were analyzed through techniques as RGA, OAP, FTIR, ATR and Raman spectrophotometry. CF3 is the main specie emitted from PFA and FEP when irradiated with MeV protons. H and HF are released from ETFE due to the broken C-F and C-H bonds when the polymer is irradiated with keV Nitrogen ions and protons. At high fluence, especially for keV Si and N, damage due to carbonization is observed with the formation of hydroperoxide and polymer dehydroflorination. The main broken bonds in PVDC are C-O and C-Cl, with the release of Cl and the formation of double carbon bonds. The ion fluence that causes damage, which could compromise fluoropolymer film applications, has been determined.

Immediate two-stage prosthetic breast reconstruction failure: radiation is not the only culprit.

PubMed

Lam, Thomas C; Borotkanics, Robert; Hsieh, Frank; Salinas, James; Boyages, John

2018-03-15

Immediate prosthetic breast reconstruction produces a satisfactory aesthetic result with high levels of patient satisfaction. However, with the broader indication for post-mastectomy adjuvant radiation, many patients are advised against immediate breast reconstruction because of concerns of implant loss and infection particularly as most patients also require chemotherapy. This retrospective cohort study examines outcomes for patients who underwent immediate two-stage prosthetic breast reconstruction after mastectomy with or without adjuvant chemotherapy or radiotherapy (RT). Between 1998 and 2010, 452 patients undergoing two-stage prosthetic immediate breast reconstruction involving a total of 562 breasts were included in this study. Stage one was defined as insertion of the temporary expander and stage two insertion of the final silicone implant. Post-operative adjuvant radiotherapy was recommended with tissue expander in-situ for 114 patients. Complications, including loss of prosthesis, seroma and infection were recorded and analysed. Cosmetic result was assessed using a 4-point scale. Post-operative prosthesis loss was 2.7%, 5.3% for patients undergoing adjuvant chemotherapy increasing to 11.3% for patients receiving chemotherapy+RT. Chemotherapy and radiotherapy independently were the main, statistically significant, risk factors for expander or implant loss; IRR: 13.85 (p=0.012) and 2.23 (p=0.027), respectively. Prosthesis loss for patients undergoing combination chemotherapy+RT was also significant; IRR: 4.791 (p<0.001). These findings serve to better inform patients on risk in weighing treatment options. Post-mastectomy radiation doubles the risk of prosthesis loss over and above adjuvant chemotherapy but is an acceptable option following immediate prosthetic breast reconstruction in a multidisciplinary setting.

Ion implantation damage, annealing and dopant activation in epitaxial gallium nitride

NASA Astrophysics Data System (ADS)

Suvkhanov, Agajan

2001-07-01

Successful n- and p-doping of GaN is an extremely important technological problem. More recently, ion implantation has been used to achieve both n- and p-type GaN. The ion implantation process is accompanied by the presence of radiation defects as the result of the ion-solid interactions. The temperatures (above 1000°C) required for recovery of the implantation induced damage and dopant activation strongly affect the GaN's surface integrity due to the significant nitrogen vapor pressure. Preservation of the surface integrity of GaN during high temperature post-implantation annealing is one of the key issues in the fabrication of GaN-based light-emitting devices. The radiation damage build-up in the implanted GaN layers has been investigated as a function of ion dose and the substrate's temperature. Results of measurements of structural damage by the Rutherford backscattering/Channeling (RBS/C) and the spectroscopic ellipsometry (SE) techniques have demonstrated the complex nature of the damage build-up. Analysis of GaN implanted at high temperature has demonstrated the presence of competing processes of layer-by-layer damage build-up and defect annihilation. Using a capping layer and annealing in a sealed quartz capsule filled with dry nitrogen can preserve the integrity of the GaN's surface. In this work the ion-implanted GaN samples were capped with 40 run MOCVD (Metal Organic Chemical Vapor Deposition) grown AlN film prior to annealing. The results of this work showed the advantage of high-temperature annealing of implanted GaN in a quartz capsule with nitrogen ambient, as compared with annealing in argon and nitrogen gas flow. Partial to complete decomposition of the AlN cap and underlying GaN has been observed by RBS/C and SEM (Scanning electron microscopy) for the samples annealed in flowing argon, as well as for the samples processed in flowing nitrogen. Encapsulation with nitrogen overpressure prevented the decomposition of the AlN capping film and the GaN crystal, and made it possible to achieve optical activation of the implanted Mg + and Si+ ions. PL measurements at 16 K of GaN samples implanted with Mg+ and annealed in a capsule showed three relatively strong peaks at 211, 303, and 395 meV from the band-edge emission. The relative intensity of the "yellow" band emission (i.e. defect band) was several times lower in the case of annealing in a sealed capsule as compared to that of open anneals in flowing argon or nitrogen. A separate set of specially-grown GaN samples was used for low temperature (1.8 K) PL analysis of the activation properties of Mg+-implanted and Mg+/P+-implanted samples. The samples were annealed in Rapid thermal processor (RTP) at 1300°C for 10 s with AlON encapsulation in flowing N2. The Mg+ implants showed good optical activation, producing a dose-correlated acceptor bound exciton peak with 12.2 meV localization energy, and donor-to-acceptor and band-to-acceptor peaks at 3.270 and 3.284 eV, respectively. The spectroscopic Mg acceptor binding energy was found to be 224 meV. A broad peak at 2.35 eV is attributed to implantation-induced defects stable in p-type material.

[Radiation safety of exploitation of radiation sources at the civil aviation airlines].

PubMed

Afanas'ev, R V; Zuev, V G; Berezin, G I; Sereda, V N; Zasiad'ko, A K

2004-01-01

Radiation risks from isotope-containing equipment, and ionizing and unused X-ray radiation sources are characterized and relevant normative documents with safety requirements to radiation sources installation, radiation safety of aircraft servicing and repair, hand luggage control and heavy luggage registration, personal protection items, system of radiation monitoring at airlines and aircraft works, and liability for breach of performance guidelines are cited.

Scintillator Detector Development at Central Michigan University

NASA Astrophysics Data System (ADS)

McClain, David; Estrade, Alfredo; Neupane, Shree

2017-09-01

Experimental nuclear physics relies both on the accuracy and precision of the instruments for radiation detection used in experimental setups. At Central Michigan University we have setup a lab to work with scintillator detectors for radioactive ion beam experiments, using a Picosecond Laser and radioactive sources for testing. We have tested the resolution for prototypes of large area scintillators that could be used for fast timing measurements in the focal plane of spectrometers, such as the future High Rigidity Spectrometer at the Facility for Rare Isotope Beams (FRIB). We measured the resolution as a function of the length of the detector, and also the position of the beam along the scintillator. We have also designed a scintillating detector to veto light ion background in beta-decay experiments with the Advanced Implantation Detector Array (AIDA) at RIKEN in Japan. We tested different configurations of Silicon Photomultipliers and scintillating fiber optics to find the best detection efficiency.

Hard disk drive based microsecond X-ray chopper for characterization of ionization chambers and photodiodes.

PubMed

Müller, O; Lützenkirchen-Hecht, D; Frahm, R

2015-03-01

A fast X-ray chopper capable of producing ms long X-ray pulses with a typical rise time of few μs was realized. It is ideally suited to investigate the temporal response of X-ray detectors with response times of the order of μs to ms, in particular, any kind of ionization chambers and large area photo diodes. The drive mechanism consists of a brushless DC motor and driver electronics from a common hard disk drive, keeping the cost at an absolute minimum. Due to its simple construction and small dimensions, this chopper operates at home lab based X-ray tubes and synchrotron radiation sources as well. The dynamics of the most important detectors used in time resolved X-ray absorption spectroscopy, namely, ionization chambers and Passivated Implanted Planar Silicon photodiodes, were investigated in detail. The results emphasize the applicability of this X-ray chopper.

Compact optical transconductance varistor

DOEpatents

Sampayan, Stephen

2015-09-22

A compact radiation-modulated transconductance varistor device having both a radiation source and a photoconductive wide bandgap semiconductor material (PWBSM) integrally formed on a substrate so that a single interface is formed between the radiation source and PWBSM for transmitting PWBSM activation radiation directly from the radiation source to the PWBSM.

[Polymer ocular implants for controlled release of drugs. I. Animal testing of the materials].

PubMed

Czechowicz-Janicka, K; Romaniuk, I; Piekarniak, A; Wicha-Brzuchalska, A; Galant, S; Rosiak, J

1992-01-01

Presented are the results of trials with hydrogel inserts received by radiation method and applied into the conjunctival sac of rabbits. In the future they can serve for incorporation of some definite drugs.

Apparatus and method for detecting gamma radiation

DOEpatents

Sigg, Raymond A.

1994-01-01

A high efficiency radiation detector for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data.

Radiation damage in Tb-implanted CaF 2 observed by channeling and luminescence measurements

NASA Astrophysics Data System (ADS)

Aono, K.; Kumagai, M.; Iwaki, M.; Aoyagi, Y.; Namba, S.

1993-06-01

The effects of 100 keV Tb ion implantation in CaF 2 single crystals have been investigated using Rutherford backscattering/channeling technique and luminescence spectra during ion implantation, depending on ion doses. Terbium ions were implanted into (111)-cut CaF 2 single crystals in random directions with doses ranging from 1 × 10 13 to 1 × 10 17 Tb +/cm 2 at -100°C, 25°C and 100°C. The luminescence signals were measured by 100 keV Ar ion beam irradiation at room temperature to Tb-implanted specimens in order to detect the ionic state of Tb. Two broad emission peaks (near 380 and 545 nm) in visible regions were observed, originating from Tb 3+ in CaF 2. The same luminescence was also observed even during Tb implantation to CaF 2. The luminescence near 380 nm is identified as an emission of 5D 3→ 7F 6 and that near 545 nm is 5D 4→ 7F 5. The emission peak intensities depend on ion dose. Channeling measurements suggest that most of the Tb atoms occupy substitutional lattice sites. Intensities of luminescence and Tb depth profiles depend on the target temperature. In conclusion, implanted Tb atoms occupy Ca lattice sites and emit green luminescence light.

Numerical Investigation of a Chip Printed Antenna Performances for Wireless Implantable Body Area Network Applications

NASA Astrophysics Data System (ADS)

Ramli, N. H.; Jaafar, H.; Lee, Y. S.

2018-03-01

Recently, wireless implantable body area network (WiBAN) system become an active area of research due to their various applications such as healthcare, support systems for specialized occupations and personal communications. Biomedical sensors networks mounted in the human body have drawn greater attention for health care monitoring systems. The implantable chip printed antenna for WiBAN applications is designed and the antenna performances is investigated in term of gain, efficiency, return loss, operating bandwidth and radiation pattern at different environments. This paper is presents the performances of implantable chip printed antenna in selected part of human body (hand, chest, leg, heart and skull). The numerical investigation is done by using human voxel model in built in the CST Microwave Studio Software. Results proved that the chip printed antenna is suitable to implant in the human hand model. The human hand model has less complex structure as it consists of skin, fat, muscle, blood and bone. Moreover, the antenna is implanted under the skin. Therefore the signal propagation path length to the base station at free space environment is considerably short. The antenna’s gain, efficiency and Specific Absorption Rate (SAR) are - 13.62dBi, 1.50 % and 0.12 W/kg respectively; which confirms the safety of the antenna usage. The results of the investigations can be used as guidance while designing chip implantable antenna in future.

Accuracy Evaluation of a Stereolithographic Surgical Template for Dental Implant Insertion Using 3D Superimposition Protocol.

PubMed

Cristache, Corina Marilena; Gurbanescu, Silviu

2017-01-01

of this study was to evaluate the accuracy of a stereolithographic template, with sleeve structure incorporated into the design, for computer-guided dental implant insertion in partially edentulous patients. Sixty-five implants were placed in twenty-five consecutive patients with a stereolithographic surgical template. After surgery, digital impression was taken and 3D inaccuracy of implants position at entry point, apex, and angle deviation was measured using an inspection tool software. Mann-Whitney U test was used to compare accuracy between maxillary and mandibular surgical guides. A p value < .05 was considered significant. Mean (and standard deviation) of 3D error at the entry point was 0.798 mm (±0.52), at the implant apex it was 1.17 mm (±0.63), and mean angular deviation was 2.34 (±0.85). A statistically significant reduced 3D error was observed at entry point p = .037, at implant apex p = .008, and also in angular deviation p = .030 in mandible when comparing to maxilla. The surgical template used has proved high accuracy for implant insertion. Within the limitations of the present study, the protocol for comparing a digital file (treatment plan) with postinsertion digital impression may be considered a useful procedure for assessing surgical template accuracy, avoiding radiation exposure, during postoperative CBCT scanning.

Method and system for determining radiation shielding thickness and gamma-ray energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klann, Raymond T.; Vilim, Richard B.; de la Barrera, Sergio

2015-12-15

A system and method for determining the shielding thickness of a detected radiation source. The gamma ray spectrum of a radiation detector is utilized to estimate the shielding between the detector and the radiation source. The determination of the shielding may be used to adjust the information from known source-localization techniques to provide improved performance and accuracy of locating the source of radiation.

Novel digital imaging techniques to assess the outcome in oral rehabilitation with dental implants: a narrative review.

PubMed

Benic, Goran I; Elmasry, Moustafa; Hämmerle, Christoph H F

2015-09-01

To examine the literature on novel digital imaging techniques for the assessment of outcomes in oral rehabilitation with dental implants. An electronic search of Medline and Embase databases including studies published prior to 28th December 2014 was performed and supplemented by a manual search. A synthesis of the publications was presented describing the use of computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography, optical scanning, spectrophotometry or optical coherence tomography (OCT) related to the outcome measures in implant therapy. Most of the digital imaging techniques have not yet sufficiently been validated to be used for outcome measures in implant dentistry. In clinical research, cone beam CT (CBCT) is increasingly being used for 3D assessment of bone and soft tissue following augmentation procedures and implant placement. Currently, there are no effective methods for the reduction of artifacts around implants in CBCT. Optical scanning is being used for the 3D assessment of changes in the soft tissue contour. The combination of optical scan with pre-operative CBCT allows the determination of the implant position and its spatial relation to anatomical structures. Spectrophotometry is the method most commonly used to objectively assess the color match of reconstructions and peri-implant mucosa to natural dentition and gingiva. New optical imaging techniques may be considered possible approaches for monitoring peri-implant soft tissue health. MRI and ultrasonography appear promising non-ionizing radiation imaging modalities for the assessment of soft tissue and bone defect morphologies. Optical scanners and OCT may represent efficient clinical methods for accurate assessment of the misfit between the reconstructions and the implants. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Radiological protection, safety and security issues in the industrial and medical applications of radiation sources

NASA Astrophysics Data System (ADS)

Vaz, Pedro

2015-11-01

The use of radiation sources, namely radioactive sealed or unsealed sources and particle accelerators and beams is ubiquitous in the industrial and medical applications of ionizing radiation. Besides radiological protection of the workers, members of the public and patients in routine situations, the use of radiation sources involves several aspects associated to the mitigation of radiological or nuclear accidents and associated emergency situations. On the other hand, during the last decade security issues became burning issues due to the potential malevolent uses of radioactive sources for the perpetration of terrorist acts using RDD (Radiological Dispersal Devices), RED (Radiation Exposure Devices) or IND (Improvised Nuclear Devices). A stringent set of international legally and non-legally binding instruments, regulations, conventions and treaties regulate nowadays the use of radioactive sources. In this paper, a review of the radiological protection issues associated to the use of radiation sources in the industrial and medical applications of ionizing radiation is performed. The associated radiation safety issues and the prevention and mitigation of incidents and accidents are discussed. A comprehensive discussion of the security issues associated to the global use of radiation sources for the aforementioned applications and the inherent radiation detection requirements will be presented. Scientific, technical, legal, ethical, socio-economic issues are put forward and discussed.

Trends in funding, internationalization, and types of study for original articles published in five implant-related journals between 2005 and 2009.

PubMed

Barão, Valentim Adelino Ricardo; Shyamsunder, Nodesh; Yuan, Judy Chia-Chun; Knoernschild, Kent L; Assunção, Wirley Gonçalves; Sukotjo, Cortino

2012-01-01

The aims of this study were to evaluate the trends in funding, geographic origin, and study types of original articles in the dental implant literature and to investigate the relationships among these factors. Articles published in Clinical Oral Implants Research, The International Journal of Oral and Maxillofacial Implants, Clinical Implant Dentistry and Related Research, Implant Dentistry, and Journal of Oral Implantology from 2005 to 2009 were reviewed. Nonoriginal articles were excluded. For each article included, extramural funding source, geographic origin, and study type were recorded. Descriptive and analytic analyses (α = .05), including a logistic regression analysis, and chi-square test were used where appropriate. Of a total of 2,085 articles published, 1,503 met the inclusion criteria. The most common source of funding was from industry (32.4%). The proportion of studies that reported funding increased significantly over time. Europe represented the highest percentage (55.8%) of published articles. Most of the articles reported on clinical studies (49.9%), followed by animal studies (25.9%). Articles from Asia and South America and animal and in vitro studies were significantly more likely to be funded. Almost half of the original dental implant articles were funded. The trend toward internationalization of authorship was evident. A strong association was observed between funding and geographic origin and between funding and study type. Most studies in North America and Europe were clinical studies and supported by industry, whereas a greater proportion of studies in Asia and South America were in vitro or animal studies funded through government resources.

Surface modification of ferritic steels using MEVVA and duoplasmatron ion sources

NASA Astrophysics Data System (ADS)

Kulevoy, Timur V.; Chalyhk, Boris B.; Fedin, Petr A.; Sitnikov, Alexey L.; Kozlov, Alexander V.; Kuibeda, Rostislav P.; Andrianov, Stanislav L.; Orlov, Nikolay N.; Kravchuk, Konstantin S.; Rogozhkin, Sergey V.; Useinov, Alexey S.; Oks, Efim M.; Bogachev, Alexey A.; Nikitin, Alexander A.; Iskandarov, Nasib A.; Golubev, Alexander A.

2016-02-01

Metal Vapor Vacuum Arc (MEVVA) ion source (IS) is a unique tool for production of high intensity metal ion beam that can be used for material surface modification. From the other hand, the duoplasmatron ion source provides the high intensity gas ion beams. The MEVVA and duoplasmatron IS developed in Institute for Theoretical and Experimental Physics were used for the reactor steel surface modification experiments. Response of ferritic-martensitic steel specimens on titanium and nitrogen ions implantation and consequent vacuum annealing was investigated. Increase in microhardness of near surface region of irradiated specimens was observed. Local chemical analysis shows atom mixing and redistribution in the implanted layer followed with formation of ultrafine precipitates after annealing.

Technical aids for the flexible use of the Leksell stereotactic system.

PubMed

Salcman, M; Bellis, E H; Sewchand, W; Amin, P

1989-06-01

As part of a multimodality therapy program for intracranial tumours, 105 stereotactic and implant procedures have been carried out utilizing the CT-compatible Leksell stereotactic system. In the iridium implant series, 86 catheters have been implanted for an average of 3.6 targets per patient. There have been no deaths or missed targets and only two incidential haemorrhages detected. In order to facilitate the reliability, safety and speed of multiple catheter insertion, several techniques have been developed including: (a) a standardized single-length catheter and flange system; (b) a ceramic catheter for microwave hyperthermia; (c) a mnemonic card for ease of calculation; (d) a radiation shield for nursing; (e) a stereotactic drill and surgical approaches to far lateral and posterior fossa targets. Principles for the use of these technical aids are discussed.

Ion beam sputter modification of the surface morphology of biological implants

NASA Technical Reports Server (NTRS)

Weigand, A. J.; Banks, B. A.

1976-01-01

The surface chemistry and texture of materials used for biological implants may significantly influence their performance and biocompatibility. Recent interest in the microscopic control of implant surface texture has led to the evaluation of ion beam sputtering as a potentially useful surface roughening technique. Ion sources, similar to electron bombardment ion thrusters designed for propulsive applications, are used to roughen the surfaces of various biocompatible alloys or polymer materials. These materials are typically used for dental implants, orthopedic prostheses, vascular prostheses, and artificial heart components. Masking techniques and resulting surface textures are described along with progress concerning evaluation of the biological response to the ion beam sputtered surfaces.

Ion-beam-sputter modification of the surface morphology of biological implants

NASA Technical Reports Server (NTRS)

Weigand, A. J.; Banks, B. A.

1977-01-01

The surface chemistry and texture of materials used for biological implants may significantly influence their performance and biocompatibility. Recent interest in the microscopic control of implant surface texture has led to the evaluation of ion-beam sputtering as a potentially useful surface roughening technique. Ion sources, similar to electron-bombardment ion thrusters designed for propulsive applications, are used to roughen the surfaces of various biocompatible alloys or polymer materials. These materials are typically used for dental implants, orthopedic prostheses, vascular prostheses, and artificial heart components. Masking techniques and resulting surface textures are described along with progress concerning evaluation of the biological response to the ion-beam-sputtered surfaces.

Music Therapy for Preschool Cochlear Implant Recipients

PubMed Central

Gfeller, Kate; Driscoll, Virginia; Kenworthy, Maura; Van Voorst, Tanya

2010-01-01

This paper provides research and clinical information relevant to music therapy for preschool children who use cochlear implants (CI). It consolidates information from various disciplinary sources regarding (a) cochlear implantation of young prelingually-deaf children (~age 2-5), (b) patterns of auditory and speech-language development, and (c) research regarding music perception of children with CIs. This information serves as a foundation for the final portion of the article, which describes typical music therapy goals and examples of interventions suitable for preschool children. PMID:23904691

Clinical evaluation of a commercial orthopedic metal artifact reduction tool for CT simulations in radiation therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Hua; Noel, Camille; Chen, Haijian

Purpose: Severe artifacts in kilovoltage-CT simulation images caused by large metallic implants can significantly degrade the conspicuity and apparent CT Hounsfield number of targets and anatomic structures, jeopardize the confidence of anatomical segmentation, and introduce inaccuracies into the radiation therapy treatment planning process. This study evaluated the performance of the first commercial orthopedic metal artifact reduction function (O-MAR) for radiation therapy, and investigated its clinical applications in treatment planning. Methods: Both phantom and clinical data were used for the evaluation. The CIRS electron density phantom with known physical (and electron) density plugs and removable titanium implants was scanned on amore » Philips Brilliance Big Bore 16-slice CT simulator. The CT Hounsfield numbers of density plugs on both uncorrected and O-MAR corrected images were compared. Treatment planning accuracy was evaluated by comparing simulated dose distributions computed using the true density images, uncorrected images, and O-MAR corrected images. Ten CT image sets of patients with large hip implants were processed with the O-MAR function and evaluated by two radiation oncologists using a five-point score for overall image quality, anatomical conspicuity, and CT Hounsfield number accuracy. By utilizing the same structure contours delineated from the O-MAR corrected images, clinical IMRT treatment plans for five patients were computed on the uncorrected and O-MAR corrected images, respectively, and compared. Results: Results of the phantom study indicated that CT Hounsfield number accuracy and noise were improved on the O-MAR corrected images, especially for images with bilateral metal implants. The {gamma} pass rates of the simulated dose distributions computed on the uncorrected and O-MAR corrected images referenced to those of the true densities were higher than 99.9% (even when using 1% and 3 mm distance-to-agreement criterion), suggesting that dose distributions were clinically identical. In all patient cases, radiation oncologists rated O-MAR corrected images as higher quality. Formerly obscured critical structures were able to be visualized. The overall image quality and the conspicuity in critical organs were significantly improved compared with the uncorrected images: overall quality score (1.35 vs 3.25, P= 0.0022); bladder (2.15 vs 3.7, P= 0.0023); prostate and seminal vesicles/vagina (1.3 vs 3.275, P= 0.0020); rectum (2.8 vs 3.9, P= 0.0021). The noise levels of the selected ROIs were reduced from 93.7 to 38.2 HU. On most cases (8/10), the average CT Hounsfield numbers of the prostate/vagina on the O-MAR corrected images were closer to the referenced value (41.2 HU, an average measured from patients without metal implants) than those on the uncorrected images. High {gamma} pass rates of the five IMRT dose distribution pairs indicated that the dose distributions were not significantly affected by the CT image improvements. Conclusions: Overall, this study indicated that the O-MAR function can remarkably reduce metal artifacts and improve both CT Hounsfield number accuracy and target and critical structure visualization. Although there was no significant impact of the O-MAR algorithm on the calculated dose distributions, we suggest that O-MAR corrected images are more suitable for the entire treatment planning process by offering better anatomical structure visualization, improving radiation oncologists' confidence in target delineation, and by avoiding subjective density overrides of artifact regions on uncorrected images.« less

Clinical evaluation of a commercial orthopedic metal artifact reduction tool for CT simulations in radiation therapy

PubMed Central

Li, Hua; Noel, Camille; Chen, Haijian; Harold Li, H.; Low, Daniel; Moore, Kevin; Klahr, Paul; Michalski, Jeff; Gay, Hiram A.; Thorstad, Wade; Mutic, Sasa

2012-01-01

Purpose: Severe artifacts in kilovoltage-CT simulation images caused by large metallic implants can significantly degrade the conspicuity and apparent CT Hounsfield number of targets and anatomic structures, jeopardize the confidence of anatomical segmentation, and introduce inaccuracies into the radiation therapy treatment planning process. This study evaluated the performance of the first commercial orthopedic metal artifact reduction function (O-MAR) for radiation therapy, and investigated its clinical applications in treatment planning. Methods: Both phantom and clinical data were used for the evaluation. The CIRS electron density phantom with known physical (and electron) density plugs and removable titanium implants was scanned on a Philips Brilliance Big Bore 16-slice CT simulator. The CT Hounsfield numbers of density plugs on both uncorrected and O-MAR corrected images were compared. Treatment planning accuracy was evaluated by comparing simulated dose distributions computed using the true density images, uncorrected images, and O-MAR corrected images. Ten CT image sets of patients with large hip implants were processed with the O-MAR function and evaluated by two radiation oncologists using a five-point score for overall image quality, anatomical conspicuity, and CT Hounsfield number accuracy. By utilizing the same structure contours delineated from the O-MAR corrected images, clinical IMRT treatment plans for five patients were computed on the uncorrected and O-MAR corrected images, respectively, and compared. Results: Results of the phantom study indicated that CT Hounsfield number accuracy and noise were improved on the O-MAR corrected images, especially for images with bilateral metal implants. The γ pass rates of the simulated dose distributions computed on the uncorrected and O-MAR corrected images referenced to those of the true densities were higher than 99.9% (even when using 1% and 3 mm distance-to-agreement criterion), suggesting that dose distributions were clinically identical. In all patient cases, radiation oncologists rated O-MAR corrected images as higher quality. Formerly obscured critical structures were able to be visualized. The overall image quality and the conspicuity in critical organs were significantly improved compared with the uncorrected images: overall quality score (1.35 vs 3.25, P = 0.0022); bladder (2.15 vs 3.7, P = 0.0023); prostate and seminal vesicles/vagina (1.3 vs 3.275, P = 0.0020); rectum (2.8 vs 3.9, P = 0.0021). The noise levels of the selected ROIs were reduced from 93.7 to 38.2 HU. On most cases (8/10), the average CT Hounsfield numbers of the prostate/vagina on the O-MAR corrected images were closer to the referenced value (41.2 HU, an average measured from patients without metal implants) than those on the uncorrected images. High γ pass rates of the five IMRT dose distribution pairs indicated that the dose distributions were not significantly affected by the CT image improvements. Conclusions: Overall, this study indicated that the O-MAR function can remarkably reduce metal artifacts and improve both CT Hounsfield number accuracy and target and critical structure visualization. Although there was no significant impact of the O-MAR algorithm on the calculated dose distributions, we suggest that O-MAR corrected images are more suitable for the entire treatment planning process by offering better anatomical structure visualization, improving radiation oncologists’ confidence in target delineation, and by avoiding subjective density overrides of artifact regions on uncorrected images. PMID:23231300

10 CFR 35.2406 - Records of brachytherapy source accountability.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Records of brachytherapy source accountability. 35.2406... Records of brachytherapy source accountability. (a) A licensee shall maintain a record of brachytherapy source accountability required by § 35.406 for 3 years. (b) For temporary implants, the record must...

Coherent Synchrotron-Based Micro-Imaging Employed for Studies of Micro-Gap Formation in Dental Implants

NASA Astrophysics Data System (ADS)

Rack, T.; Zabler, S.; Rack, A.; Stiller, M.; Riesemeier, H.; Cecilia, A.; Nelson, K.

2011-09-01

Biocompatible materials such as titanium are regularly applied in oral surgery. Titanium-based implants for the replacement of missing teeth demand a high mechanical precision in order to minimize micro-bacterial leakage, especially when two-piece concepts are used. Synchrotron-based hard x-ray radiography, unlike conventional laboratory radiography, allows high spatial resolution in combination with high contrast even when micro-sized features in such highly attenuating objects are visualized. Therefore, micro-gap formation at interfaces in two-piece dental implants with the sample under different mechanical loads can be studied. We show the existence of micro-gaps in implants with conical connections and study the mechanical behavior of the mating zone of conical implants during loading. The micro-gap is a potential source of implant failure, i.e., bacterial leakage, which can be a stimulus for an inflammatory process.

A Suggested Model for Building Robust Biomedical Implants Registries.

PubMed

Aloufi, Bader; Alshagathrah, Fahad; Househ, Mowafa

2017-01-01

Registries are an essential source of information for clinical and non-clinical decision-makers; because they provide evidence for post-market clinical follow-up and early detection of safety signals for biomedical implants. Yet, many of todays biomedical implants registries are facing a variety of challenges relating to a poorly designed dataset, the reliability of inputted data and low clinician and patient participation. The purpose of this paper is to present a best practice model for the implementation and use of biomedical implants registries to monitor the safety and effectiveness of implantable medical devices. Based on a literature review and an analysis of multiple national relevant registries, we identified six factors that address contemporary challenges and are believed to be the keys for building a successful biomedical implants registry, which include: sustainable development, international comparability, data reliability, purposeful design, ease of patient participation, and collaborative development at the national level.

Coherent Synchrotron-Based Micro-Imaging Employed for Studies of Micro-Gap Formation in Dental Implants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rack, T.; Stiller, M.; Nelson, K.

Biocompatible materials such as titanium are regularly applied in oral surgery. Titanium-based implants for the replacement of missing teeth demand a high mechanical precision in order to minimize micro-bacterial leakage, especially when two-piece concepts are used. Synchrotron-based hard x-ray radiography, unlike conventional laboratory radiography, allows high spatial resolution in combination with high contrast even when micro-sized features in such highly attenuating objects are visualized. Therefore, micro-gap formation at interfaces in two-piece dental implants with the sample under different mechanical loads can be studied. We show the existence of micro-gaps in implants with conical connections and study the mechanical behavior ofmore » the mating zone of conical implants during loading. The micro-gap is a potential source of implant failure, i.e., bacterial leakage, which can be a stimulus for an inflammatory process.« less

Transcutaneous RF-Powered Implantable Minipump Driven by a Class-E Transmitter

PubMed Central

Moore, William H.; Holschneider, Daniel P.; Givrad, Tina K.

2007-01-01

We describe the design and testing of an inductive coupling system used to power an implantable minipump for applications in ambulating rats. A 2 MHz class-E oscillator driver powered a coil transmitter wound around a 33-cm-diameter rat cage. A receiver coil, a filtered rectifier, and a voltage-sensitive switch powered the implant. The implant DC current at the center of the primary coil (5.1 V) exceeded the level required to activate the solenoid valve in the pump. The variations of the implant current in the volume of the primary coil reflected the variations of the estimated coupling coefficient between the two coils. The pump could be activated in-vivo, while accommodating the vertical and horizontal movements of the animal. Advantages of this design include a weight reduction for the implant, an operation independent from a finite power source, and a remote activation/deactivation. PMID:16916107

Transcutaneous RF-powered implantable minipump driven by a class-E transmitter.

PubMed

Moore, William H; Holschneider, Daniel P; Givrad, Tina K; Maarek, Jean-Michel I

2006-08-01

We describe the design and testing of an inductive coupling system used to power an implantable minipump for applications in ambulating rats. A 2 MHz class-E oscillator driver powered a coil transmitter wound around a 33-cm-diameter rat cage. A receiver coil, a filtered rectifier, and a voltage-sensitive switch powered the implant. The implant DC current at the center of the primary coil (5.1 V) exceeded the level required to activate the solenoid valve in the pump. The variations of the implant current in the volume of the primary coil reflected the variations of the estimated coupling coefficient between the two coils. The pump could be activated in-vivo, while accommodating the vertical and horizontal movements of the animal. Advantages of this design include a weight reduction for the implant, an operation independent from a finite power source, and a remote activation/deactivation.

New materials based on polylactide modified with silver and carbon ions

NASA Astrophysics Data System (ADS)

Kurzina, I. A.; Pukhova, I. V.; Botvin, V. V.; Davydova, D. V.; Filimoshkin, A. G.; Savkin, K. P.; Oskomov, K. V.; Oks, E. M.

2015-11-01

An integrated study of poly-L-lactide (PL) synthesis and the physicochemical properties of film surfaces, both modified by silver and carbon ion implantation and also unmodified PL surfaces, has been carried out. Surface modification was done using aMevva-5.Ru metal ion source with ion implantation doses of 1.1014, 1.1015 and 1.1016 ion/cm2. Material characterization was done using NMR, IRS, XPS and AFM. The molecular weight (MW), micro-hardness, surface resistivity, and limiting wetting angle of both un-implanted and implanted samples were measured. The results reveal that degradation of PL macromolecules occurs during ion implantation, followed by CO or CO2 removal and MW decrease. With increasing implantation dose, the glycerol wettability of the PL surface increases but the water affinity decreases (hydrophobic behavior). After silver and carbon ion implantation into the PL samples, the surface resistivity is reduced by several orders of magnitude and a tendency to micro-hardness reductionis induced.

Effect of implanted helium on tensile properties and hardness of 9% Cr martensitic stainless steels

NASA Astrophysics Data System (ADS)

Jung, P.; Henry, J.; Chen, J.; Brachet, J.-C.

2003-05-01

Hundred micrometer thick specimens of 9% Cr martensitic steels EM10 and T91 were homogeneously implanted with He 4 to concentrations up to 0.5 at.% at temperatures from 150 to 550 °C. The specimens were tensile tested at room temperature and at the respective implantation temperatures. Subsequently the fracture surfaces were analysed by scanning electron microscopy and some of the specimens were examined in an instrumented hardness tester. The implanted helium caused hardening and embrittlement which both increased with increasing helium content and with decreasing implantation temperature. Fracture surfaces showed intergranular brittle appearance with virtually no necking at the highest implantation doses, when implanted below 250 °C. The present tensile results can be scaled to tensile data after irradiation in spallation sources on the basis of helium content but not on displacement damage. An interpretation of this finding by microstructural examination is given in a companion paper [J. Nucl. Mater., these Proceedings].

State-of-the-art on cone beam CT imaging for preoperative planning of implant placement.

PubMed

Guerrero, Maria Eugenia; Jacobs, Reinhilde; Loubele, Miet; Schutyser, Filip; Suetens, Paul; van Steenberghe, Daniel

2006-03-01

Orofacial diagnostic imaging has grown dramatically in recent years. As the use of endosseous implants has revolutionized oral rehabilitation, a specialized technique has become available for the preoperative planning of oral implant placement: cone beam computed tomography (CT). This imaging technology provides 3D and cross-sectional views of the jaws. It is obvious that this hardware is not in the same class as CT machines in cost, size, weight, complexity, and radiation dose. It is thus considered to be the examination of choice when making a risk-benefit assessment. The present review deals with imaging modalities available for preoperative planning purposes with a specific focus on the use of the cone beam CT and software for planning of oral implant surgery. It is apparent that cone beam CT is the medium of the future, thus, many changes will be performed to improve these. Any adaptation of the future systems should go hand in hand with a further dose optimalization.

Porcelain-coated antenna for radio-frequency driven plasma source

DOEpatents

Leung, K.N.; Wells, R.P.; Craven, G.E.

1996-12-24

A new porcelain-enamel coated antenna creates a clean plasma for volume or surface-conversion ion sources. The porcelain-enamel coating is hard, electrically insulating, long lasting, non fragile, and resistant to puncture by high energy ions in the plasma. Plasma and ion production using the porcelain enamel coated antenna is uncontaminated with filament or extraneous metal ions because the porcelain does not evaporate and is not sputtered into the plasma during operation. Ion beams produced using the new porcelain-enamel coated antenna are useful in ion implantation, high energy accelerators, negative, positive, or neutral beam applications, fusion, and treatment of chemical or radioactive waste for disposal. For ion implantation, the appropriate species ion beam generated with the inventive antenna will penetrate large or small, irregularly shaped conducting objects with a narrow implantation profile. 8 figs.

Quantifying shape changes of silicone breast implants in a murine model using in vivo micro-CT.

PubMed

Anderson, Emily E; Perilli, Egon; Carati, Colin J; Reynolds, Karen J

2017-08-01

A major complication of silicone breast implants is the formation of a capsule around the implant known as capsular contracture which results in the distortion of the implant. Recently, a mouse model for studying capsular contracture was examined using micro-computed tomography (micro-CT), however, only qualitative changes were reported. The aim of this study was to develop a quantitative method for comparing the shape changes of silicone implants using in vivo micro-CT. Mice were bilaterally implanted with silicone implants and underwent ionizing radiation to induce capsular contracture. On day 28 post-surgery mice were examined in vivo using micro-CT. The reconstructed cross-section images were visually inspected to identify distortion. Measurements were taken in 2D and 3D to quantify the shape of the implants in the normal (n = 11) and distorted (n = 5) groups. The degree of anisotropy was significantly higher in the distorted implants in the transaxial view (0.99 vs. 1.19, p = 0.002) and the y-axis lengths were significantly shorter in the sagittal (9.27 mm vs. 8.55 mm, p = 0.015) and coronal (9.24 mm vs. 8.76 mm, p = 0.031) views, indicating a deviation from the circular cross-section and shortening of the long axis. The 3D analysis revealed a significantly lower average thickness (sphere-fitting method) in distorted implants (6.86 mm vs. 5.49 mm, p = 0.002), whereas the volume and surface area did not show significant changes. Statistically significant differences between normal and distorted implants were found in 2D and 3D using distance measurements performed via micro-CT. This objective analysis method can be useful for a range of studies involving deformable implants using in vivo micro-CT. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1447-1452, 2017. © 2016 Wiley Periodicals, Inc.

Orbital implants in retinoblastoma patients: 23 years of experience and a review of the literature.

PubMed

Mourits, Daphne L; Moll, Annette C; Bosscha, Machteld I; Tan, H Stevie; Hartong, Dyonne T

2016-03-01

To evaluate complications of different types of orbital implants following enucleation for retinoblastoma. We performed a retrospective chart study of all patients that underwent enucleation as treatment of retinoblastoma between April 1991 and June 2013. Events of implant exposure, extrusion (defined as a complete loss of the implant, or a major exposure that could not be closed) and socket abnormalities were analysed for association with implant type and influence of additional external beam radiation therapy (EBRT) and/or chemotherapy. A total of 224 enucleations in 216 patients (eight bilateral) were identified. Mean age at surgery was 1.9 (median 1.5) years. Of the 219 included enucleated eyes, 20 were not replaced by a primary implant and 18 were replaced by an Allen implant. Scleral wrapped hydroxyapatite (HA) and acrylic implants (polymethylmethacrylate) were inserted in, respectively, 79 and 102 cases. In the total population, 29 treatment or implant-specific events (13.2%) were registered. Main complications were implant exposure n = 10 (4.6%) and extrusion n = 6 (2.7%). The acrylic/sclera group had less exposures or extrusions (5 of 102, 4.9%) compared to the HA/sclera group (10 of 79, 12.7%), although this difference did not quite reach statistical significance (p = 0.06). Additional treatment (chemotherapy and/or EBRT for the fellow eye) was administered in 78 cases (35.8%). The overall complication rate in the entire study population was significantly higher (16.7% versus 5.7%) in the group exposed to additional therapy (OR 3.3; 95% CI 1.30-8.36 p = 0.008). This negative effect of additional therapy was also significant in the combined acrylic/HA group (OR 2.9; 95% CI 0.97-8.46 p = 0.048). Our results suggest a favourable outcome for acrylic implants compared to the HA implant. Additional treatment with chemotherapy and/or EBRT is associated with an increased risk of complications. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

32 CFR 655.10 - Use of radiation sources by non-Army entities on Army land (AR 385-11).

Code of Federal Regulations, 2010 CFR

2010-07-01

... radioisotope; or (5) A machine-produced ionizing-radiation source capable of producing an area, accessible to... NARM and machine-produced ionizing radiation sources, the applicant has an appropriate State... 32 National Defense 4 2010-07-01 2010-07-01 true Use of radiation sources by non-Army entities on...

Determination of Jet Noise Radiation Source Locations using a Dual Sideline Cross-Correlation/Spectrum Technique

NASA Technical Reports Server (NTRS)

Allen, C. S.; Jaeger, S. M.

1999-01-01

The goal of our efforts is to extrapolate nearfield jet noise measurements to the geometric far field where the jet noise sources appear to radiate from a single point. To accomplish this, information about the location of noise sources in the jet plume, the radiation patterns of the noise sources and the sound pressure level distribution of the radiated field must be obtained. Since source locations and radiation patterns can not be found with simple single microphone measurements, a more complicated method must be used.

Iatrogenic radiation exposure to patients with early onset spine and chest wall deformities.

PubMed

Khorsand, Derek; Song, Kit M; Swanson, Jonathan; Alessio, Adam; Redding, Gregory; Waldhausen, John

2013-08-01

Retrospective cohort series. Characterize average iatrogenic radiation dose to a cohort of children with thoracic insufficiency syndrome (TIS) during assessment and treatment at a single center with vertically expandable prosthetic titanium rib. Children with TIS undergo extensive evaluations to characterize their deformity. No standardized radiographical evaluation exists, but all reports use extensive imaging. The source and level of radiation these patients receive is not currently known. We evaluated a retrospective consecutive cohort of 62 children who had surgical treatment of TIS at our center from 2001-2011. Typical care included obtaining serial radiographs, spine and chest computed tomographic (CT) scans, ventilation/perfusion scans, and magnetic resonance images. Epochs of treatment were divided into time of initial evaluation to the end of initial vertically expandable prosthetic titanium rib implantation with each subsequent epoch delineated by the next surgical intervention. The effective dose for each examination was estimated within millisieverts (mSv). Plain radiographs were calculated from references. Effective dose was directly estimated for CT scans since 2007 and an average of effective dose from 2007-2011 was used for scans before 2007. Effective dose from fluoroscopy was directly estimated. All doses were reported in mSv. A cohort of 62 children had a total of 447 procedures. There were a total of 290 CT scans, 4293 radiographs, 147 magnetic resonance images, and 134 ventilation/perfusion scans. The average accumulated effective dose was 59.6 mSv for children who had completed all treatment, 13.0 mSv up to initial surgery, and 3.2 mSv for each subsequent epoch of treatment. CT scans accounted for 74% of total radiation dose. Children managed for TIS using a consistent protocol received iatrogenic radiation doses that were on average 4 times the estimated average US background radiation exposure of 3 mSv/yr. CT scans comprised 74% of the total dose. 3.

Apparatus and method for detecting gamma radiation

DOEpatents

Sigg, R.A.

1994-12-13

A high efficiency radiation detector is disclosed for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data. 4 figures.

The elimination of free radicals in irradiated UHMWPEs with and without vitamin E stabilization by annealing under pressure.

PubMed

Oral, Ebru; Ghali, Bassem W; Muratoglu, Orhun K

2011-04-01

Radiation crosslinking of ultrahigh molecular weight polyethylene (UHMWPE) has been used to decrease the wear of joint implant bearing surfaces. While radiation crosslinking has been successful in decreasing femoral head penetration into UHMWPE acetabular liners in vivo, postirradiation thermal treatment of the polymer is required to ensure the oxidative stability of joint implants in the long term. Two types of thermal treatment have been used: (i) annealing below the melting point preserves the mechanical properties but the residual free radicals trapped in the crystalline regions are not completely eliminated, leading to oxidation in the long-term and (ii) annealing above the melting point (melting) eliminates the free radicals but leads to a decrease in mechanical properties through loss of crystallinity during the melting process. In this study, we hypothesized that free radicals could be reduced by annealing below the melting point under pressure effectively without melting due to the elevation of the melting point. By avoiding the complete melting of UHMWPE, mechanical properties would be preserved. Our hypothesis tested positive in that we found the radiation-induced free radicals to be markedly reduced (below the detection limit of state-of-the-art electron spin resonance) by thermal annealing under pressure in radiation crosslinked virgin UHMWPE and UHMWPE/vitamin-E blends without loss of mechanical properties. Copyright © 2011 Wiley Periodicals, Inc.

Effects of vanadium ion implantation on microstructure, mechanical and tribological properties of TiN coatings

NASA Astrophysics Data System (ADS)

Deng, Bin; Tao, Ye; Guo, Deliang

2012-09-01

TiN coatings were deposited on the substrates of cemented carbide (WC-TiC-Co) by Magnetic Filter Arc Ion Plating (MFAIP) and then implanted with vanadium through Metal Vacuum Vapor Arc (MEVVA) ion source with the doses of 1 × 1017 and 5 × 1017 ions/cm2 at 40 kV. The microstructures and chemical compositions of the V-implanted TiN coatings were investigated using Glancing Incidence X-ray Diffraction (GIXRD) and X-ray Photoelectron Spectroscopy (XPS), together with the mechanical and tribological properties of coatings were characterized using nano-indentation and ball-on-disk tribometer. It was found that the diffraction peaks of the V-implanted TiN coatings at the doses of 5 × 1017 ions/cm2 shifted to higher angles and became broader. The hardness and elastic modulus of TiN coatings increased after V ion implantation. The wear mechanism for both un-implanted and V-implanted TiN coatings against GCr15 steel ball was adhesive wear, and the V-implanted TiN coatings had a lower friction coefficient as well as a better wear resistance

Artificial heart development program. Volume I. System development. Phase III summary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1977-01-01

The report documents efforts and results in the development of the power system portions of a calf implantable model of nuclear-powered artificial heart. The primary objective in developing the implantable model was to solve the packaging problems for total system implantation. The power systems portion is physically that portion of the implantable model between the Pu-238 heat sources and the blood pump ventricles. The work performed had two parallel themes. The first of these was the development of an integrated implantable model for bench and animal experiments plus design effort on a more advanced model. The second was research andmore » development on components of the system done in conjunction with the development of the implantable model and to provide technology for incorporation into advanced models plus support to implantations, at the University of Utah, of the systems blood pumping elements when driven by electric motor. The efforts and results of implantable model development are covered, mainly, in the text of the report. The research and development efforts and results are reported, primarily, in the appendices (Vol. 2).« less

BrachyView: multiple seed position reconstruction and comparison with CT post-implant dosimetry

NASA Astrophysics Data System (ADS)

Alnaghy, S.; Loo, K. J.; Cutajar, D. L.; Jalayer, M.; Tenconi, C.; Favoino, M.; Rietti, R.; Tartaglia, M.; Carriero, F.; Safavi-Naeini, M.; Bucci, J.; Jakubek, J.; Pospisil, S.; Zaider, M.; Lerch, M. L. F.; Rosenfeld, A. B.; Petasecca, M.

2016-05-01

BrachyView is a novel in-body imaging system utilising high-resolution pixelated silicon detectors (Timepix) and a pinhole collimator for brachytherapy source localisation. Recent studies have investigated various options for real-time intraoperative dynamic dose treatment planning to increase the quality of implants. In a previous proof-of-concept study, the justification of the pinhole concept was shown, allowing for the next step whereby multiple active seeds are implanted into a PMMA phantom to simulate a more realistic clinical scenario. In this study, 20 seeds were implanted and imaged using a lead pinhole of 400 μ m diameter. BrachyView was able to resolve the seed positions within 1-2 mm of expected positions, which was verified by co-registering with a full clinical post-implant CT scan.

SU-C-17A-02: Sirius MRI Markers for Prostate Post-Implant Assessment: MR Protocol Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, T; Wang, J; Kudchadker, R

Purpose: Currently, CT is used to visualize prostate brachytherapy sources, at the expense of accurate structure contouring. MRI is superior to CT for anatomical delineation, but the sources appear as voids on MRI images. Previously we have developed Sirius MRI markers (C4 Imaging) to replace spacers to assist source localization on MRI images. Here we develop an MRI pulse sequence protocol that enhances the signal of these markers to enable MRI-only post-implant prostate dosimetric analysis. Methods: To simulate a clinical scenario, a CIRS multi-modality prostate phantom was implanted with 66 markers and 86 sources. The implanted phantom was imaged onmore » both 1.5T and 3.0T GE scanners under various conditions, different pulse sequences (2D fast spin echo [FSE], 3D balanced steadystate free precession [bSSFP] and 3D fast spoiled gradient echo [FSPGR]), as well as varying amount of padding to simulate various patient sizes and associated signal fall-off from the surface coil elements. Standard FSE sequences from the current clinical protocols were also evaluated. Marker visibility, marker size, intra-marker distance, total scan time and artifacts were evaluated for various combinations of echo time, repetition time, flip angle, number of excitations, bandwidth, slice thickness and spacing, fieldof- view, frequency/phase encoding steps and frequency direction. Results: We have developed a 3D FSPGR pulse sequence that enhances marker signal and ensures the integrity of the marker shape while maintaining reasonable scan time. For patients contraindicated for 3.0T, we have also developed a similar sequence for 1.5T scanners. Signal fall-off with distance from prostate to coil can be compensated mainly by decreasing bandwidth. The markers are not visible using standard FSE sequences. FSPGR sequences are more robust for consistent marker visualization as compared to bSSFP sequences. Conclusion: The developed MRI pulse sequence protocol for Sirius MRI markers assists source localization to enable MRIonly post-implant prostate dosimetric analysis. S.J. Frank is a co-founder of C4 Imaging (manufactures the MRI markers)« less

Social media utilization in the cochlear implant community.

PubMed

Saxena, Rajeev C; Lehmann, Ashton E; Hight, A Ed; Darrow, Keith; Remenschneider, Aaron; Kozin, Elliott D; Lee, Daniel J

2015-02-01

More than 200,000 individuals worldwide have received a cochlear implant (CI). Social media Websites may provide a paramedical community for those who possess or are interested in a CI. The utilization patterns of social media by the CI community, however, have not been thoroughly investigated. The purpose of this study was to investigate participation of the CI community in social media Websites. We conducted a systematic survey of online CI-related social media sources. Using standard search engines, the search terms cochlear implant, auditory implant, forum, and blog identified relevant social media platforms and Websites. Social media participation was quantified by indices of membership and posts. Social media sources included Facebook, Twitter, YouTube, blogs, and online forums. Each source was assigned one of six functional categories based on its description. No intervention was performed. We conducted all online searches in February 2014. Total counts of each CI-related social media source were summed, and descriptive statistics were calculated. More than 350 sources were identified, including 60 Facebook groups, 36 Facebook pages, 48 Twitter accounts, 121 YouTube videos, 13 forums, and 95 blogs. The most active online communities were Twitter accounts, which totaled 35,577 members, and Facebook groups, which totaled 17,971 members. CI users participated in Facebook groups primarily for general information/support (68%). Online forums were the next most active online communities by membership. The largest forum contained approximately 9,500 topics with roughly 127,000 posts. CI users primarily shared personal stories through blogs (92%), Twitter (71%), and YouTube (62%). The CI community engages in the use of a wide range of online social media sources. The CI community uses social media for support, advocacy, rehabilitation information, research endeavors, and sharing of personal experiences. Future studies are needed to investigate how social media Websites may be harnessed to improve patient-provider relationships and potentially used to augment patient education. American Academy of Audiology.

Social Media Utilization in the Cochlear Implant Community

PubMed Central

Saxena, Rajeev C.; Lehmann, Ashton E.; Hight, A. Ed; Darrow, Keith; Remenschneider, Aaron; Kozin, Elliott D.; Lee, Daniel J.

2015-01-01

Background More than 200,000 individuals worldwide have received a cochlear implant (CI). Social media Websites may provide a paramedical community for those who possess or are interested in a CI. The utilization patterns of social media by the CI community, however, have not been thoroughly investigated. Purpose The purpose of this study was to investigate participation of the CI community in social media Websites. Research Design We conducted a systematic survey of online CI-related social media sources. Using standard search engines, the search terms cochlear implant, auditory implant, forum, and blog identified relevant social media platforms and Websites. Social media participation was quantified by indices of membership and posts. Study Sample Social media sources included Facebook, Twitter, YouTube, blogs, and online forums. Each source was assigned one of six functional categories based on its description. Intervention No intervention was performed. Data Collection and Analysis We conducted all online searches in February 2014. Total counts of each CI-related social media source were summed, and descriptive statistics were calculated. Results More than 350 sources were identified, including 60 Facebook groups, 36 Facebook pages, 48 Twitter accounts, 121 YouTube videos, 13 forums, and 95 blogs. The most active online communities were Twitter accounts, which totaled 35,577 members, and Facebook groups, which totaled 17,971 members. CI users participated in Facebook groups primarily for general information/support (68%). Online forums were the next most active online communities by membership. The largest forum contained approximately 9,500 topics with roughly 127,000 posts. CI users primarily shared personal stories through blogs (92%), Twitter (71%), and YouTube (62%). Conclusions The CI community engages in the use of a wide range of online social media sources. The CI community uses social media for support, advocacy, rehabilitation information, research endeavors, and sharing of personal experiences. Future studies are needed to investigate how social media Websites may be harnessed to improve patient-provider relationships and potentially used to augment patient education. PMID:25690778

Low dose of continuous – wave microwave irradiation did not cause temperature increase in muscles tissue adjacent to titanium alloy implants – an animal study

PubMed Central

2013-01-01

Background Research studies on the influence of radiofrequency electromagnetic radiation on implants in vitro have failed to investigate temperature changes in the tissues adjacent to the implants under microwave therapy. We therefore, used a rabbit model in an effort to determine the impact of microwave therapy on temperature changes in tissues adjacent to the titanium alloy implants and the safety profile thereof. Methods Titanium alloy internal fixation plates were implanted in New Zealand rabbits in the middle of femur. Microwave therapy was performed by a 2450 MHz microwave generator 3 days after the surgery. Temperature changes of muscles adjacent to the implants were recorded under exposure to dose-gradient microwave radiation from 20w to 60w. Results Significant difference between control and microwave treatment group at peak temperatures (Tpeak) and temperature gap (Tgap= Tpeak-Tvally) were observed in deep muscles (Tpeak, 41.63 ± 0.21°C vs. 44.40 ± 0.17°C, P < 0.01; Tgap, 5.33 ± 0.21°C vs. 8.10 ± 0.36°C, P < 0.01) and superficial muscles (Tpeak, 41.53 ± 0.15°C vs. 42.03 ± 0.23°C, P = 0.04; Tgap, 5.23 ± 0.21°C vs. 5.80 ± 0.17°C, P = 0.013) under 60 w, and deep muscles (Tpeak, 40.93 ± 0.25°C vs. 41.87 ± 0.23°C, P = 0.01; Tgap, 4.73 ± 0.20°C vs. 5.63 ± 0.35°C, P = 0.037) under 50w, but not under 20, 30 and 40w. Conclusion Our results suggest that low-dose (20w-40w) continuous-wave microwave irradiation delivered by a 2450 MHz microwave generator might be a promising treatment for patients with titanium alloy internal fixation, as it did not raise temperature in muscle tissues adjacent to the titanium alloy implant. PMID:24365389

Cone beam computed tomography in implant dentistry: recommendations for clinical use.

PubMed

Jacobs, Reinhilde; Salmon, Benjamin; Codari, Marina; Hassan, Bassam; Bornstein, Michael M

2018-05-15

In implant dentistry, three-dimensional (3D) imaging can be realised by dental cone beam computed tomography (CBCT), offering volumetric data on jaw bones and teeth with relatively low radiation doses and costs. The latter may explain why the market has been steadily growing since the first dental CBCT system appeared two decades ago. More than 85 different CBCT devices are currently available and this exponential growth has created a gap between scientific evidence and existing CBCT machines. Indeed, research for one CBCT machine cannot be automatically applied to other systems. Supported by a narrative review, recommendations for justified and optimized CBCT imaging in oral implant dentistry are provided. The huge range in dose and diagnostic image quality requires further optimization and justification prior to clinical use. Yet, indications in implant dentistry may go beyond diagnostics. In fact, the inherent 3D datasets may further allow surgical planning and transfer to surgery via 3D printing or navigation. Nonetheless, effective radiation doses of distinct dental CBCT machines and protocols may largely vary with equivalent doses ranging between 2 to 200 panoramic radiographs, even for similar indications. Likewise, such variation is also noticed for diagnostic image quality, which reveals a massive variability amongst CBCT technologies and exposure protocols. For anatomical model making, the so-called segmentation accuracy may reach up to 200 μm, but considering wide variations in machine performance, larger inaccuracies may apply. This also holds true for linear measures, with accuracies of 200 μm being feasible, while sometimes fivefold inaccuracy levels may be reached. Diagnostic image quality may also be dramatically hampered by patient factors, such as motion and metal artefacts. Apart from radiodiagnostic possibilities, CBCT may offer a huge therapeutic potential, related to surgical guides and further prosthetic rehabilitation. Those additional opportunities may surely clarify part of the success of using CBCT for presurgical implant planning and its transfer to surgery and prosthetic solutions. Hence, dental CBCT could be justified for presurgical diagnosis, preoperative planning and peroperative transfer for oral implant rehabilitation, whilst striving for optimisation of CBCT based machine-dependent, patient-specific and indication-oriented variables.

One-step breast reconstruction with polyurethane-covered implants after skin-sparing mastectomy.

PubMed

Rancati, Alberto; Soderini, Alejandro; Dorr, Julio; Gercovich, Gustavo; Tessari, Luciano; Gonzalez, Eduardo

2013-12-01

Skin-sparing mastectomy (SSM) and immediate one-step breast reconstruction with implants has become an increasingly popular, effective treatment for selected patients with breast carcinoma. However, it is associated with high complication rates. Breast augmentation with polyurethane-covered implants (PCIs) has consistently had optimal short-term and long-term results with low rates of capsular contracture. The aim of this study was to evaluate the clinical and aesthetic outcomes of immediate one-step breast reconstruction with PCI after SSM in early breast cancer patients at a single institution. We reviewed the records of 221 consecutive breast cancer patients who underwent one-stage immediate reconstruction with PCI after SSM from 1995 through 2005. Patient and tumour characteristics, type of reconstruction, postoperative complications, aesthetic results and recurrence rate were analysed. The mean age of the patients was 52±11 years (range, 30-76; standard deviation (SD), 11). The American Joint Committee on Cancer (AJCC) pathologic stages were 0 (10%), I (63.3%) and II (26.7%). Thirty-nine (17.65%; confidence interval (CI)=13.04-23.1) of the 221 patients had complications; seven had prosthesis extrusion requiring an implant (five due to skin necrosis, one due to infection and one due to late haematoma). In six of these seven cases, the procedure was indicated for local recurrence after conservative breast surgery with adjunctive radiation therapy (rescue procedure). Thirty-two (14.4%) patients had minor complications: 12 had cutaneous rash, four had malpositioned implants and 16 had inadequate implant projection. At long-term follow-up, four (1.8%) patients had developed grade IV capsular contracture associated with postoperative radiation therapy. At a median follow-up of 98 months (range, 36-156), 14 (6.3%) patients had tumour recurrence and 12.2% had distant metastasis. Nineteen patients had died of cancer, and 192 (86.8%) remained disease free. One-stage immediate breast reconstruction with PCI after SSM appears to be oncologically safe and provides a high level of patient satisfaction. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Solid-state radiation-emitting compositions and devices

DOEpatents

Ashley, Carol S.; Brinker, C. Jeffrey; Reed, Scott; Walko, Robert J.

1992-01-01

The invention relates to a composition for the volumetric generation of radiation, wherein a first substance functions as a source of exciting radiation, and a second substance interacts with the exciting radiation to provide a second radiation. The compositions comprise a porous substrate which is loaded with: a source of exciting radiation, a component capable of emitting radiation upon interaction with the exciting radiation, or both. Preferably, the composition is an aerogel substrate loaded with both a source of exciting radiation, such as tritium, and a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce radiation of a second energy.

Solid-state radiation-emitting compositions and devices

DOEpatents

Ashley, C.S.; Brinker, C.J.; Reed, S.; Walko, R.J.

1992-08-11

The invention relates to a composition for the volumetric generation of radiation, wherein a first substance functions as a source of exciting radiation, and a second substance interacts with the exciting radiation to provide a second radiation. The compositions comprise a porous substrate which is loaded with: a source of exciting radiation, a component capable of emitting radiation upon interaction with the exciting radiation, or both. Preferably, the composition is an aerogel substrate loaded with both a source of exciting radiation, such as tritium, and a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce radiation of a second energy. 4 figs.

DNA-dependent protein kinase is a molecular target for the development of noncytotoxic radiation-sensitizing drugs.

PubMed

Shinohara, Eric T; Geng, Ling; Tan, Jiahui; Chen, Heidi; Shir, Yu; Edwards, Eric; Halbrook, James; Kesicki, Edward A; Kashishian, Adam; Hallahan, Dennis E

2005-06-15

DNA-dependent protein kinase (DNA-PK)-defective severe combined immunodeficient (SCID) mice have a greater sensitivity to ionizing radiation compared with wild-type mice due to deficient repair of DNA double-strand break. SCID cells were therefore studied to determine whether radiosensitization by the specific inhibitor of DNA-PK, IC87361, is eliminated in the absence of functional DNA-PK. IC87361 enhanced radiation sensitivity in wild-type C57BL6 endothelial cells but not in SCID cells. The tumor vascular window model was used to assess IC87361-induced radiosensitization of SCID and wild-type tumor microvasculature. Vascular density was 5% in irradiated SCID host compared with 50% in C57BL6 mice (P < 0.05). IC87361 induced radiosensitization of tumor microvasculature in wild-type mice that resembled the radiosensitive phenotype of tumor vessels in SCID mice. Radiosensitization by IC87361 was eliminated in SCID tumor vasculature, which lack functional DNA-PK. Irradiated LLC and B16F0 tumors implanted into SCID mice showed greater tumor growth delay compared with tumors implanted into either wild-type C57BL6 or nude mice. Furthermore, LLC tumors treated with radiation and IC87361 showed tumor growth delay that was significantly greater than tumors treated with radiation alone (P < 0.01 for 3 Gy alone versus 3 Gy + IC87361). DNA-PK inhibitors induced no cytotoxicity and no toxicity in mouse normal tissues. Mouse models deficient in enzyme activity are useful to assess the specificity of novel kinase inhibitors. DNA-PK is an important target for the development of novel radiation-sensitizing drugs that have little intrinsic cytotoxicity.

Complications After Total Skin-Sparing Mastectomy and Expander-Implant Reconstruction: Effects of Radiation Therapy on the Stages of Reconstruction.

PubMed

Peled, Anne Warren; Sears, Marie; Wang, Frederick; Foster, Robert D; Alvarado, Michael; Wong, Jasmine; Ewing, Cheryl A; Sbitany, Hani; Esserman, Laura J; Fowble, Barbara

2018-01-01

Many patients undergoing total-skin sparing mastectomy (TSSM) and 2-staged expander-implant (TE-I) reconstruction require postmastectomy radiation therapy (PMRT). Additionally, many patients undergoing TSSM for recurrent cancer have a history of lumpectomy and radiation therapy (XRT). Few studies have looked at the impact of XRT on the stages of TE-I reconstruction. Patients undergoing TSSM and immediate TE-I reconstruction between 2006 and 2013 were identified from a prospectively maintained database. Rates of TE-I loss and severe infection requiring intravenous antibiotics were compared in patients with prior XRT (85 cases) and PMRT (133 cases). Complications were divided by stage of reconstruction: first stage (TSSM and TE placement) and second stage (TE-I exchange). Mean follow-up time was 2.5 years. Patients with prior XRT had more complications after the first stage of reconstruction than the second (TE-I loss: 15% vs 5%, P = 0.03; infection: 20% vs 8%, P = 0.04). Patients receiving PMRT had low complication rates after the first stage, when they had not yet received radiation (TE-I loss: 2%; infection: 5%). However, complication rates after TE-I exchange (TE-I loss, 18%; infection, 31%) were significantly higher, and nearly 4-fold higher than patients with prior XRT. Patients with prior XRT are at high risk for complications after the first stage of TE-I reconstruction after TSSM; however, the risk of complications at the second stage is comparable to patients without radiation exposure and significantly lower than patients receiving PMRT. Patients receiving radiation therapy should be given appropriate preoperative counseling regarding their risks.

SU-F-T-44: A Comparison of the Pre-Plan, Intra-Operative Plan, and Post-Implant Dosimetry for a Prostate Implant Case Using Prefabricated Linear Polymer-Encapsulated Pd-103

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheu, R; Powers, A; McGee, H

Purpose: To investigate the reproducibility and limitations of Pd-103 prostate brachytherapy using fixed length linear sources (CivaString). Methods: An LDR prostate brachytherapy case which was preplanned on MR images with prefabricated linear polymer-encapsulated Pd-103 sources (CivaString) was studied and compared with ultrasound based intra-operative planning and CT based post-implant dosimetry. We evaluated the following parameters among the three studies: prostate geometry (volume and cross sectional area), needle position and alignment deviations, and dosimetry parameters (D90). Results: The prostate volumes and axial cross sectional areas at center of prostate were measured as 41.8, 39.3 and 36.8 cc, and 14.9, 14.3, andmore » 11.3 respectively on pre-plan MR, inter-op US, and post-implant CT studies. The deviation of prostate volumes and axial cross sectional areas measured on pre-planning MR and intra-operative US were within 5%. 17 out of 19 pre-planned needles were positioned within 5mm (the template grid size). One needle location was adjusted intra-operatively and another needle was removed due to proximity to urethra. The needle pathways were not always parallel to the trans-rectal probe due to the flexibility of CivaString. The angle of deviation was up to 10 degrees. Two pairs of needles were exchanged to better fit the length of prostate at the time of implant. This resulted in a prostate D90 of 153.8 Gy (124%) and 131.4 Gy (106.7%) for intra-op and PID respectively. Conclusion: Preplanning is a necessary part of implants performed with prefabricated linear polymer sources. However, as is often the case, there were real-time deviations from the pre-plan. Intra-op planning provides the ability conform to anatomy at the time of implant. Therefore, we propose to develop a systematic way to order extra strings of different length to provide the flexibility to perform intra-operative planning with fixed length strands.« less

Advantages and Limits of 4H-SIC Detectors for High- and Low-Flux Radiations

NASA Astrophysics Data System (ADS)

Sciuto, A.; Torrisi, L.; Cannavò, A.; Mazzillo, M.; Calcagno, L.

2017-11-01

Silicon carbide (SiC) detectors based on Schottky diodes were used to monitor low and high fluxes of photons and ions. An appropriate choice of the epilayer thickness and geometry of the surface Schottky contact allows the tailoring and optimizing the detector efficiency. SiC detectors with a continuous front electrode were employed to monitor alpha particles in a low-flux regime emitted by a radioactive source with high energy (>5.0 MeV) or generated in an ion implanter with sub-MeV energy. An energy resolution value of 0.5% was measured in the high energy range, while, at energy below 1.0 MeV, the resolution becomes 10%; these values are close to those measured with a traditional silicon detector. The same SiC devices were used in a high-flux regime to monitor high-energy ions, x-rays and electrons of the plasma generated by a high-intensity (1016 W/cm2) pulsed laser. Furthermore, SiC devices with an interdigit Schottky front electrode were proposed and studied to overcome the limits of the such SiC detectors in the detection of low-energy (˜1.0 keV) ions and photons of the plasmas generated by a low-intensity (1010 W/cm2) pulsed laser. SiC detectors are expected to be a powerful tool for the monitoring of radioactive sources and ion beams produced by accelerators, for a complete characterization of radiations emitted from laser-generated plasmas at high and low temperatures, and for dosimetry in a radioprotection field.

Relationship between Sponsorship and Failure Rate of Dental Implants: A Systematic Approach

PubMed Central

Popelut, Antoine; Valet, Fabien; Fromentin, Olivier; Thomas, Aurélie; Bouchard, Philippe

2010-01-01

Background The number of dental implant treatments increases annually. Dental implants are manufactured by competing companies. Systematic reviews and meta-analysis have shown a clear association between pharmaceutical industry funding of clinical trials and pro-industry results. So far, the impact of industry sponsorship on the outcomes and conclusions of dental implant clinical trials has never been explored. The aim of the present study was to examine financial sponsorship of dental implant trials, and to evaluate whether research funding sources may affect the annual failure rate. Methods and Findings A systematic approach was used to identify systematic reviews published between January 1993 and December 2008 that specifically deal with the length of survival of dental implants. Primary articles were extracted from these reviews. The failure rate of the dental implants included in the trials was calculated. Data on publication year, Impact Factor, prosthetic design, periodontal status reporting, number of dental implants included in the trials, methodological quality of the studies, presence of a statistical advisor, and financial sponsorship were extracted by two independent reviewers (kappa  = 0.90; CI95% [0.77–1.00]). Univariate quasi-Poisson regression models and multivariate analysis were used to identify variables that were significantly associated with failure rates. Five systematic reviews were identified from which 41 analyzable trials were extracted. The mean annual failure rate estimate was 1.09%.(CI95% [0.84–1.42]). The funding source was not reported in 63% of the trials (26/41). Sixty-six percent of the trials were considered as having a risk of bias (27/41). Given study age, both industry associated (OR = 0.21; CI95% [0.12–0.38]) and unknown funding source trials (OR = 0.33; (CI95% [0.21–0.51]) had a lower annual failure rates compared with non-industry associated trials. A conflict of interest statement was disclosed in 2 trials. Conclusions When controlling for other factors, the probability of annual failure for industry associated trials is significantly lower compared with non-industry associated trials. This bias may have significant implications on tooth extraction decision making, research on tooth preservation, and governmental health care policies. PMID:20422000

Polyatomic ions from a high current ion implanter driven by a liquid metal ion source.

PubMed

Pilz, W; Laufer, P; Tajmar, M; Böttger, R; Bischoff, L

2017-12-01

High current liquid metal ion sources are well known and found their first application as field emission electric propulsion thrusters in space technology. The aim of this work is the adaption of such kind of sources in broad ion beam technology. Surface patterning based on self-organized nano-structures on, e.g., semiconductor materials formed by heavy mono- or polyatomic ion irradiation from liquid metal (alloy) ion sources (LMAISs) is a very promising technique. LMAISs are nearly the only type of sources delivering polyatomic ions from about half of the periodic table elements. To overcome the lack of only very small treated areas by applying a focused ion beam equipped with such sources, the technology taken from space propulsion systems was transferred into a large single-end ion implanter. The main component is an ion beam injector based on high current LMAISs combined with suited ion optics allocating ion currents in the μA range in a nearly parallel beam of a few mm in diameter. Different types of LMAIS (needle, porous emitter, and capillary) are presented and characterized. The ion beam injector design is specified as well as the implementation of this module into a 200 kV high current ion implanter operating at the HZDR Ion Beam Center. Finally, the obtained results of large area surface modification of Ge using polyatomic Bi 2 + ions at room temperature from a GaBi capillary LMAIS will be presented and discussed.

Polyatomic ions from a high current ion implanter driven by a liquid metal ion source

NASA Astrophysics Data System (ADS)

Pilz, W.; Laufer, P.; Tajmar, M.; Böttger, R.; Bischoff, L.

2017-12-01

High current liquid metal ion sources are well known and found their first application as field emission electric propulsion thrusters in space technology. The aim of this work is the adaption of such kind of sources in broad ion beam technology. Surface patterning based on self-organized nano-structures on, e.g., semiconductor materials formed by heavy mono- or polyatomic ion irradiation from liquid metal (alloy) ion sources (LMAISs) is a very promising technique. LMAISs are nearly the only type of sources delivering polyatomic ions from about half of the periodic table elements. To overcome the lack of only very small treated areas by applying a focused ion beam equipped with such sources, the technology taken from space propulsion systems was transferred into a large single-end ion implanter. The main component is an ion beam injector based on high current LMAISs combined with suited ion optics allocating ion currents in the μA range in a nearly parallel beam of a few mm in diameter. Different types of LMAIS (needle, porous emitter, and capillary) are presented and characterized. The ion beam injector design is specified as well as the implementation of this module into a 200 kV high current ion implanter operating at the HZDR Ion Beam Center. Finally, the obtained results of large area surface modification of Ge using polyatomic Bi2+ ions at room temperature from a GaBi capillary LMAIS will be presented and discussed.

Study of shallow junction formation by boron-containing cluster ion implantation of silicon and two-stage annealing

NASA Astrophysics Data System (ADS)

Lu, Xin-Ming

Shallow junction formation made by low energy ion implantation and rapid thermal annealing is facing a major challenge for ULSI (ultra large scale integration) as the line width decreases down to the sub micrometer region. The issues include low beam current, the channeling effect in low energy ion implantation and TED (transient enhanced diffusion) during annealing after ion implantation. In this work, boron containing small cluster ions, such as GeB, SiB and SiB2, was generated by using the SNICS (source of negative ion by cesium sputtering) ion source to implant into Si substrates to form shallow junctions. The use of boron containing cluster ions effectively reduces the boron energy while keeping the energy of the cluster ion beam at a high level. At the same time, it reduces the channeling effect due to amorphization by co-implanted heavy atoms like Ge and Si. Cluster ions have been used to produce 0.65--2keV boron for low energy ion implantation. Two stage annealing, which is a combination of low temperature (550°C) preannealing and high temperature annealing (1000°C), was carried out to anneal the Si sample implanted by GeB, SiBn clusters. The key concept of two-step annealing, that is, the separation of crystal regrowth, point defects removal with dopant activation from dopant diffusion, is discussed in detail. The advantages of the two stage annealing include better lattice structure, better dopant activation and retarded boron diffusion. The junction depth of the two stage annealed GeB sample was only half that of the one-step annealed sample, indicating that TED was suppressed by two stage annealing. Junction depths as small as 30 nm have been achieved by two stage annealing of sample implanted with 5 x 10-4/cm2 of 5 keV GeB at 1000°C for 1 second. The samples were evaluated by SIMS (secondary ion mass spectrometry) profiling, TEM (transmission electron microscopy) and RBS (Rutherford Backscattering Spectrometry)/channeling. Cluster ion implantation in combination with two-step annealing is effective in fabricating ultra-shallow junctions.

Fourth-generation plasma immersion ion implantation and deposition facility for hybrid surface modification layer fabrication.

PubMed

Wang, Langping; Huang, Lei; Xie, Zhiwen; Wang, Xiaofeng; Tang, Baoyin

2008-02-01

The fourth-generation plasma immersion ion implantation and deposition (PIIID) facility for hybrid and batch treatment was built in our laboratory recently. Comparing with our previous PIIID facilities, several novel designs are utilized. Two multicathode pulsed cathodic arc plasma sources are fixed on the chamber wall symmetrically, which can increase the steady working time from 6 h (the single cathode source in our previous facilities) to about 18 h. Meanwhile, the inner diameter of the pulsed cathodic arc plasma source is increased from the previous 80 to 209 mm, thus, large area metal plasma can be obtained by the source. Instead of the simple sample holder in our previous facility, a complex revolution-rotation sample holder composed of 24 shafts, which can rotate around its axis and adjust its position through revolving around the center axis of the vacuum chamber, is fixed in the center of the vacuum chamber. In addition, one magnetron sputtering source is set on the chamber wall instead of the top cover in the previous facility. Because of the above characteristic, the PIIID hybrid process involving ion implantation, vacuum arc, and magnetron sputtering deposition can be acquired without breaking vacuum. In addition, the PIIID batch treatment of cylinderlike components can be finished by installing these components on the rotating shafts on the sample holder.

Knowledge and attitudes of dental interns in Karnataka state, India, regarding implants.

PubMed

Chaudhary, Sohini; Gowda, Triveni M; Kumar, Tarun A B; Mehta, Dhoom S

2013-10-01

Implant treatment today is highly reliable as a valid restorative option for missing teeth. As more patients worldwide opt for implant treatment, it is now imperative for dental practitioners to have sound information about dental implants so they can help patients make informed decisions. This study sought to define the knowledge and attitudes regarding dental implants of dental interns in the state of Karnataka, India, and to evaluate the dental implant curriculum structure at the undergraduate level. A survey was conducted of dental interns (students in their fifth, clinical year of undergraduate study) in seven of the forty-five academic dental institutions in this state. The questionnaire consisted of fifteen questions that assessed the respondents' level of knowledge and source of information regarding implants. A total of 500 questionnaires were distributed, and 417 interns responded for a response rate of 83.4 percent. In the results, 73.3 percent reported they were not provided sufficient information about implants in their undergraduate curriculum, and 95.7 percent of them wanted more. Also, 63.5 percent of the respondents believed that high costs could limit the use of dental implants as a tooth replacement modality in India. This study concludes that revision in the undergraduate dental curricula at these schools is needed to better prepare students for practicing implant dentistry.

Long-term outcomes after primary failures of artificial urinary sphincter implantation.

PubMed

Wang, Rou; McGuire, Edward J; He, Chang; Faerber, Gary J; Latini, Jerilyn M

2012-04-01

To assess our institutional outcomes after primary artificial urinary sphincter (AUS) failures. From 1985 to 2010, a total of 149 patients underwent 318 primary and additional AUS procedures. We classified additional procedures as revisions, replacements, or explantations. At a median of 52 months (range, 6-250 months), 53% of patients had required at least 1 additional procedure beyond their initial implantation. These included 106 (63%) revisions, 42 (24.9%) explantations, and 21 (12.4%) replacements. The most common revision was reservoir upsizing (37/106). Reasons for first revision included recurrent incontinence (56.7%), mechanical malfunction (22%), and infection or erosion (18.6%). Explantations were performed primarily for infection and erosion (64.3%). Median time to first revision was 20.1 months (range, 0.1-173 months) after implantation, with a median of 9.5 months (range, 1-102 months) between revisions. Explantation occurred at a median of 22 months (range, 1-221 months) after implant, and subsequent replacement at a median of 33.6 months (range, 2-138 months). At 5 years, 28/83 (33.7%) patients had undergone no additional procedures. Patients with previous radiation were more likely to experience infection (P = .03; OR 3.99; 95% CI 1.03-15.42). Patients with previous myocardial infarction were more likely to experience erosion (P = .04; OR 2.29; 95% CI 1.05-5.02), and obese patients were more likely to experience mechanical malfunction (P = .04; OR 2.62; 95% CI 1.07-6.4). More than half of patients with an AUS will require additional procedures, most likely revision. Radiation, previous myocardial infarction, and obesity are linked to complications. Median time to first revision or explantation is slightly less than 2 years, indicating that long-term follow-up is required after initial implantation. Copyright © 2012 Elsevier Inc. All rights reserved.

75 FR 19302 - Radiation Sources on Army Land

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-14

... Nuclear Regulatory Commission (NRC) license or Army Radiation Authorization (ARA). The purpose of the ARP...-0001] Radiation Sources on Army Land AGENCY: Department of the Army, DoD. ACTION: Proposed rule... radiation sources on Army land. The Army requires Non-Army agencies (including their civilian contractors...

Zero-fluoroscopy permanent pacemaker implantation using Ensite NavX system: Clinical viability or fanciful technique?

PubMed

Guo, Ping; Qiu, Jie; Wang, Yan; Chen, Guangzhi; Proietti, Riccardo; Fadhle, Al-Selmi; Zhao, Chunxia; Wen Wang, Dao

2018-02-01

Fluoroscopy is the imaging modality routinely used for cardiac device implantation and electrophysiological procedures. Due to the rising concern regarding the harmful effects of radiation exposure to both the patients and operation staffs, novel 3D mapping systems have been developed and implemented in electrophysiological procedure for the navigation of catheters inside the heart chambers. Their applicability in cardiac device implantation has been rarely reported. Our aim is to evaluate the feasibility and safety of permanent pacemaker implantation without fluoroscopy. From January 2012 to June 2016, six patients (50 ± 15 years, four of six were female, one of who was at the 25th week of gestation) who underwent permanent pacemaker implantation were included (zero-fluoroscopy group). Data from 20 consecutive cases of implantation performed under fluoroscopy guidance were chosen as a control group (fluoroscopy group). Total implantation procedure time for single-chamber pacemaker was 51.3 ± 13.1 minutes in the zero-fluoroscopy group and 42.6 ± 7.4 minutes in the fluoroscopy group (P  =  0.155). The implantation procedural time for a dual-chamber pacemaker was 88.3 ± 19.6 minutes and 67.3 ± 7.6 minutes in the zero-fluoroscopy and fluoroscopy groups (P  =  0.013), respectively. No complications were observed during the procedure and the follow-up in the two groups, and all pacemakers worked with satisfactory parameters. Ensite NavX system can be used as a reliable and safe zero-fluoroscopy approach for the implantation of single- or dual-chamber permanent pacemakers in specific patients, such as pregnant women or in extreme situations when the x-ray machine is not available. © 2017 The Authors. Pacing and Clinical Electrophysiology published by Wiley Periodicals, Inc.

One-Step Salvage of Infected Prosthetic Breast Reconstructions Using Antibiotic-Impregnated Polymethylmethacrylate Plates and Concurrent Tissue Expander Exchange.

PubMed

Albright, Steven B; Xue, Amy S; McKnight, Aisha; Wolfswinkel, Erik M; Hollier, Larry H; Brown, Rodger H; Bullocks, Jamal M; Izaddoost, Shayan A

2016-09-01

Periprosthetic infection represents a major complication in breast reconstruction, frequently leading to expander-implant loss. Recent studies report variable success in the salvage of infected breast prostheses through systemic antibiotic therapy and surgical intervention. There is currently no consensus regarding a management algorithm for attempted salvage. The purpose of this pilot study was to evaluate the early outcomes of a protocol using antibiotic-impregnated polymethylmethacrylate (PMMA) implant placement with expander device exchange. A retrospective database was queried to identify all patients with infected implant-based breast reconstruction who were treated by the study authors and who underwent attempted salvage under the study protocol. All patients received intravenous antibiotics followed by surgical debridement of the infected pocket, insertion of antibiotic-impregnated PMMA plates and/or beads, device exchange, and postoperative antibiotics. After clinical resolution of infection, tissue expansion was performed with the PMMA implants remaining in situ until exchanged to permanent implants. All patients with infected prosthetic breast reconstructions achieved implant pocket sterilization using this method. At a mean follow-up of 8.2 months (range, 1-19 months), none of these patients have required reoperation for capsular contracture. One patient, while under treatment with prednisone for a rash, developed recurrent infection, which led to explantation of her implant. Two patients underwent radiation therapy while an antibiotic plate and tissue expander were in place, with no observed exposure or infection recurrence. Sustained local antibiotic delivery using PMMA implants and expander device exchange can successfully salvage an infected breast implant. Perceived benefits include shorter time to completed reconstruction, preserved skin envelope integrity, and possibly improved long-term aesthetic outcomes.

Micro-engineered first wall tungsten armor for high average power laser fusion energy systems

NASA Astrophysics Data System (ADS)

Sharafat, Shahram; Ghoniem, Nasr M.; Anderson, Michael; Williams, Brian; Blanchard, Jake; Snead, Lance; HAPL Team

2005-12-01

The high average power laser program is developing an inertial fusion energy demonstration power reactor with a solid first wall chamber. The first wall (FW) will be subject to high energy density radiation and high doses of high energy helium implantation. Tungsten has been identified as the candidate material for a FW armor. The fundamental concern is long term thermo-mechanical survivability of the armor against the effects of high temperature pulsed operation and exfoliation due to the retention of implanted helium. Even if a solid tungsten armor coating would survive the high temperature cyclic operation with minimal failure, the high helium implantation and retention would result in unacceptable material loss rates. Micro-engineered materials, such as castellated structures, plasma sprayed nano-porous coatings and refractory foams are suggested as a first wall armor material to address these fundamental concerns. A micro-engineered FW armor would have to be designed with specific geometric features that tolerate high cyclic heating loads and recycle most of the implanted helium without any significant failure. Micro-engineered materials are briefly reviewed. In particular, plasma-sprayed nano-porous tungsten and tungsten foams are assessed for their potential to accommodate inertial fusion specific loads. Tests show that nano-porous plasma spray coatings can be manufactured with high permeability to helium gas, while retaining relatively high thermal conductivities. Tungsten foams where shown to be able to overcome thermo-mechanical loads by cell rotation and deformation. Helium implantation tests have shown, that pulsed implantation and heating releases significant levels of implanted helium. Helium implantation and release from tungsten was modeled using an expanded kinetic rate theory, to include the effects of pulsed implantations and thermal cycles. Although, significant challenges remain micro-engineered materials are shown to constitute potential candidate FW armor materials.

Nanoparticle-based brachytherapy spacers for delivery of localized combined chemoradiation therapy.

PubMed

Kumar, Rajiv; Belz, Jodi; Markovic, Stacey; Jadhav, Tej; Fowle, William; Niedre, Mark; Cormack, Robert; Makrigiorgos, Mike G; Sridhar, Srinivas

2015-02-01

In radiation therapy (RT), brachytherapy-inert source spacers are commonly used in clinical practice to achieve high spatial accuracy. These implanted devices are critical technical components of precise radiation delivery but provide no direct therapeutic benefits. Here we have fabricated implantable nanoplatforms or chemoradiation therapy (INCeRT) spacers loaded with silica nanoparticles (SNPs) conjugated containing a drug, to act as a slow-release drug depot for simultaneous localized chemoradiation therapy. The spacers are made of poly(lactic-co-glycolic) acid (PLGA) as matrix and are physically identical in size to the commercially available brachytherapy spacers (5 mm × 0.8 mm). The silica nanoparticles, 250 nm in diameter, were conjugated with near infrared fluorophore Cy7.5 as a model drug, and the INCeRT spacers were characterized in terms of size, morphology, and composition using different instrumentation techniques. The spacers were further doped with an anticancer drug, docetaxel. We evaluated the in vivo stability, biocompatibility, and biodegradation of these spacers in live mouse tissues. The electron microscopy studies showed that nanoparticles were distributed throughout the spacers. These INCeRT spacers remained stable and can be tracked by the use of optical fluorescence. In vivo optical imaging studies showed a slow diffusion of nanoparticles from the spacer to the adjacent tissue in contrast to the control Cy7.5-PLGA spacer, which showed rapid disintegration in a few days with a burst release of Cy7.5. The docetaxel spacers showed suppression of tumor growth in contrast to control mice over 16 days. The imaging with the Cy7.5 spacer and therapeutic efficacy with docetaxel spacers supports the hypothesis that INCeRT spacers can be used for delivering the drugs in a slow, sustained manner in conjunction with brachytherapy, in contrast to the rapid clearance of the drugs when administered systemically. The results demonstrate that these spacers with tailored release profiles have potential in improving the combined therapeutic efficacy of chemoradiation therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

A miniaturized micro strip antenna based on sinusoidal patch geometry for implantable biomedical applications

NASA Astrophysics Data System (ADS)

Ibrahim, Omar A.; Elwi, Taha A.; Islam, Naz E.

2012-11-01

A miniaturized microstrip antenna is analyzed for implantable biomedical applications. The antenna is designed using two different commercial software packages, CST Microwave Studio and HFSS, to validate the results. The proposed design operates in the WMTS frequency band. The antenna performance is tested inside the human body, Hugo model. The antenna design is readjusted to get the desired resonant frequency. The resonant frequency, bandwidth, gain, and radiation pattern of the proposed antenna are provided in this paper. Furthermore, the effect of losses inside human body due to the fat layer is recognized.

An environmental dose experiment

NASA Astrophysics Data System (ADS)

Peralta, Luis

2017-11-01

Several radiation sources worldwide contribute to the delivered dose to the human population. This radiation also acts as a natural background when detecting radiation, for instance from radioactive sources. In this work a medium-sized plastic scintillation detector is used to evaluate the dose delivered by natural radiation sources. Calibration of the detector involved the use of radioactive sources and Monte Carlo simulation of the energy deposition per disintegration. A measurement of the annual dose due to background radiation to the body was then estimated. A dose value compatible with the value reported by the United Nations Scientific Committee on the Effects of Atomic Radiation was obtained.

Transperineal implantation of gold fiducial markers (gold seeds) for prostate image-guided radiation therapy: a feasible technique associated with a low risk of complications.

PubMed

Saad, Akram; Goldstein, Jeffrey; Lawrence, Yaacov Richard; Weiss, Ilana; Saad, Rasha; Spieler, Benjamin; Symon, Zvi

2015-12-01

The purpose is to describe the method, safety and efficacy of transperineal gold seed placement for image-guided radiation therapy. An ethics committee approved database was used to review records of consecutive patients from October 2008 through December 2013, who underwent transperineal implantation of three gold markers into the prostate using staged local anaesthesia and transrectal ultrasound. Seeds were counted on radiographs from CT simulation, first treatment and last treatment. Retention and use of at least three markers for kV/kV matching was considered a successful implant. A visual analogue scale (VAS) pain assessment was performed. SAS was used for data analysis. Fiducial marker placement was successful for kV/kV matching in 556/581 patients (95.7%). The procedure was aborted due to pain in two patients. Additional sedation during the procedure was required in two patients. Complications include urinary infections (2 patients, <0.5%) and transient haematuria (2 patients, <0.5%). There were no recorded calls requesting additional pain medication or delays in radiation due to complications. The number of seeds identified at simulation: 4 (2 patients), 3 (554 patients), 2 (21 patients), 1 (1 patient), 0 (1 patient). One patient with three seeds and two patients with <2 seeds had cone beam CT instead of kV/kV imaging for image guidance. No seeds were lost after simulation. The mean visual analogue pain score associated with transperineal gold seed insertion met patients' expectations (respectively 4.1 vs. 4.4 P = 0.19). Outpatient transperineal insertion of fiducials avoids the rectum, is effective, convenient, well tolerated and has few side effects.

Prostate Bed Motion During Intensity-Modulated Radiotherapy Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klayton, Tracy; Price, Robert; Buyyounouski, Mark K.

Purpose: Conformal radiation therapy in the postprostatectomy setting requires accurate setup and localization of the prostatic fossa. In this series, we report prostate bed localization and motion characteristics, using data collected from implanted radiofrequency transponders. Methods and Materials: The Calypso four-dimensional localization system uses three implanted radiofrequency transponders for daily target localization and real-time tracking throughout a course of radiation therapy. We reviewed the localization and tracking reports for 20 patients who received ultrasonography-guided placement of Calypso transponders within the prostate bed prior to a course of intensity-modulated radiation therapy at Fox Chase Cancer Center. Results: At localization, prostate bedmore » displacement relative to bony anatomy exceeded 5 mm in 9% of fractions in the anterior-posterior (A-P) direction and 21% of fractions in the superior-inferior (S-I) direction. The three-dimensional vector length from skin marks to Calypso alignment exceeded 1 cm in 24% of all 652 fractions with available setup data. During treatment, the target exceeded the 5-mm tracking limit for at least 30 sec in 11% of all fractions, generally in the A-P or S-I direction. In the A-P direction, target motion was twice as likely to move posteriorly, toward the rectum, than anteriorly. Fifteen percent of all treatments were interrupted for repositioning, and 70% of patients were repositioned at least once during their treatment course. Conclusion: Set-up errors and motion of the prostatic fossa during radiotherapy are nontrivial, leading to potential undertreatment of target and excess normal tissue toxicity if not taken into account during treatment planning. Localization and real-time tracking of the prostate bed via implanted Calypso transponders can be used to improve the accuracy of plan delivery.« less

Continuous Low-dose-rate Irradiation of Iodine-125 Seeds Inhibiting Perineural Invasion in Pancreatic Cancer.

PubMed

Lu, Zheng; Dong, Teng-Hui; Si, Pei-Ren; Shen, Wei; Bi, Yi-Liang; Min, Min; Chen, Xin; Liu, Yan

2016-10-20

Perineural invasion (PNI) is a histopathological characteristic of pancreatic cancer (PanCa). The aim of this study was to observe the treatment effect of continuous low-dose-rate (CLDR) irradiation to PNI and assess the PNI-related pain relief caused by iodine-125 ( 125 I) seed implantation. The in vitro PNI model established by co-culture with dorsal root ganglion (DRG) and cancer cells was interfered under 2 and 4 Gy of 125 I seeds CLDR irradiation. The orthotopic models of PNI were established, and 125 I seeds were implanted in tumor. The PNI-related molecules were analyzed. In 30 patients with panCa, the pain relief was assessed using a visual analog scale (VAS). Pain intensity was measured before and 1 week, 2 weeks, and 1, 3, and 6 months after 125 I seed implantation. The co-culture of DRG and PanCa cells could promote the growth of PanCa cells and DRG neurites. In co-culture groups, the increased number of DRG neurites and pancreatic cells in radiation group was significantly less. In orthotopic models, the PNI-positive rate in radiation and control group was 3/11 and 7/11; meanwhile, the degrees of PNI between radiation and control groups was significant difference (P < 0.05). At week 2, the mean VAS pain score in patients decreased by 50% and significantly improved than the score at baseline (P < 0.05). The pain scores were lower in all patients, and the pain-relieving effect was retained about 3 months. The CLDR irradiation could inhibit PNI of PanCa with the value of further study. The CLDR irradiation could do great favor in preventing local recurrence and alleviating pain.

EFFECTS OF IRRADIATION ON BRAIN VASCULATURE USING AN IN SITU TUMOR MODEL

PubMed Central

Zawaski, Janice A.; Gaber, M. Waleed; Sabek, Omaima M.; Wilson, Christy M.; Duntsch, Christopher D.; Merchant, Thomas E.

2013-01-01

Purpose Damage to normal tissue is a limiting factor in clinical radiotherapy (RT). We tested the hypothesis that the presence of tumor alters the response of normal tissues to irradiation using a rat in situ brain tumor model. Methods and Materials Intravital microscopy was used with a rat cranial window to assess the in situ effect of rat C6 glioma on peritumoral tissue with and without RT. The RT regimen included 40 Gy at 8 Gy/day starting Day 5 after tumor implant. Endpoints included blood–brain barrier permeability, clearance index, leukocyte-endothelial interactions and staining for vascular endothelial growth factor (VEGF) glial fibrillary acidic protein, and apoptosis. To characterize the system response to RT, animal survival and tumor surface area and volume were measured. Sham experiments were performed on similar animals implanted with basement membrane matrix absent of tumor cells. Results The presence of tumor alone increases permeability but has little effect on leukocyte–endothelial interactions and astrogliosis. Radiation alone increases tissue permeability, leukocyte-endothelial interactions, and astrogliosis. The highest levels of permeability and cell adhesion were seen in the model that combined tumor and irradiation; however, the presence of tumor appeared to reduce the volume of rolling leukocytes. Unirradiated tumor and peritumoral tissue had poor clearance. Irradiated tumor and peritumoral tissue had a similar clearance index to irradiated and unirradiated sham-implanted animals. Radiation reduces the presence of VEGF in peritumoral normal tissues but did not affect the amount of apoptosis in the normal tissue. Apoptosis was identified in the tumor tissue with and without radiation. Conclusions We developed a novel approach to demonstrate that the presence of the tumor in a rat intracranial model alters the response of normal tissues to irradiation. PMID:22197233

A feasibility study of ion implantation techniques for mass spectrometer calibration

NASA Technical Reports Server (NTRS)

Koslin, M. E.; Krycuk, G. A.; Schatz, J. G., Jr.; White, F. A.; Wood, G. M.

1978-01-01

An experimental study was undertaken to examine the feasibility of using ion-implanted filaments doped with either an alkali metal or noble gas for in situ recalibration of onboard mass spectrometers during extended space missions. Implants of rubidium and krypton in rhenium ribbon filaments were subsequently tested in a bakeable 60 deg sector mass spectrometer operating in the static mode. Surface ionization and electron impact ion sources were both used, each yielding satisfactory results. The metallic implant with subsequent ionization provided a means of mass scale calibration and determination of system operating parameters, whereas the noble gas thermally desorbed into the system was more suited for partial pressure and sensitivity determinations.

Wireless communication with implanted medical devices using the conductive properties of the body.

PubMed

Ferguson, John E; Redish, A David

2011-07-01

Many medical devices that are implanted in the body use wires or wireless radiofrequency telemetry to communicate with circuitry outside the body. However, the wires are a common source of surgical complications, including breakage, infection and electrical noise. In addition, radiofrequency telemetry requires large amounts of power and results in low-efficiency transmission through biological tissue. As an alternative, the conductive properties of the body can be used to enable wireless communication with implanted devices. In this article, several methods of intrabody communication are described and compared. In addition to reducing the complications that occur with current implantable medical devices, intrabody communication can enable novel types of miniature devices for research and clinical applications.

Simulation study of a high power density rectenna array for biomedical implantable devices

NASA Astrophysics Data System (ADS)

Day, John; Yoon, Hargsoon; Kim, Jaehwan; Choi, Sang H.; Song, Kyo D.

2016-04-01

The integration of wireless power transmission devices using microwaves into the biomedical field is close to a practical reality. Implanted biomedical devices need a long lasting power source or continuous power supply. Recent development of high efficiency rectenna technology enables continuous power supply to these implanted devices. Due to the size limit of most of medical devices, it is imperative to minimize the rectenna as well. The research reported in this paper reviews the effects of close packing the rectenna elements which show the potential of directly empowering the implanted devices, especially within a confined area. The rectenna array is tested in the X band frequency range.

A continuously self regenerating high-flux neutron-generator facility

NASA Astrophysics Data System (ADS)

Rogers, A. M.; Becker, T. A.; Bernstein, L. A.; van Bibber, K.; Bleuel, D. L.; Chen, A. X.; Daub, B. H.; Goldblum, B. L.; Firestone, R. B.; Leung, K.-N.; Renne, P. R.; Waltz, C.

2013-10-01

A facility based on a next-generation, high-flux D-D neutron generator (HFNG) is being constructed at UC Berkeley. The current generator, designed around two RF-driven multicusp deuterium ion sources, is capable of producing a neutron output of >1011 n/s. A specially designed titanium-coated copper target located between the ion sources accelerates D+ ions up to 150 keV, generating 2.45 MeV neutrons through the d(d,3He)n fusion reaction. Deuterium in the target is self loaded and regenerating through ion implantation, enabling stable and continuous long-term operation. The proposed science program is focused on pioneering advances in the 40Ar/39Ar dating technique for geochronology, new nuclear data measurements, basic nuclear science research including statistical model studies of radiative-strength functions and level densities, and education. An overview of the facility and its unique capabilities as well as first measurements from the HFNG commissioning will be presented. Work supported by NSF Grant No. EAR-0960138, U.S. DOE LBL Contract No. DE-AC02-05CH11231, and U.S. DOE LLNL Contract No. DE-AC52-07NA27344.

RTV silicone rubber surface modification for cell biocompatibility by negative-ion implantation

NASA Astrophysics Data System (ADS)

Zheng, Chenlong; Wang, Guangfu; Chu, Yingjie; Xu, Ya; Qiu, Menglin; Xu, Mi

2016-03-01

A negative cluster ion implantation system was built on the injector of a GIC4117 tandem accelerator. Next, the system was used to study the surface modification of room temperature vulcanization silicone rubber (RTV SR) for cell biocompatibility. The water contact angle was observed to decrease from 117.6° to 99.3° as the C1- implantation dose was increased to 1 × 1016 ions/cm2, and the effects of C1-, C2- and O1- implantation result in only small differences in the water contact angle at 3 × 1015 ions/cm2. These findings indicate that the hydrophilicity of RTV SR improves as the dose is increased and that the radiation effect has a greater influence than the doping effect on the hydrophilicity. There are two factors influence hydrophilicity of RTV: (1) based on the XPS and ATR-FTIR results, it can be inferred that ion implantation breaks the hydrophobic functional groups (Sisbnd CH3, Sisbnd Osbnd Si, Csbnd H) of RTV SR and generates hydrophilic functional groups (sbnd COOH, sbnd OH, Sisbnd (O)x (x = 3,4)). (2) SEM reveals that the implanted surface of RTV SR appears the micro roughness such as cracks and wrinkles. The hydrophilicity should be reduced due to the lotus effect (Zhou Rui et al., 2009). These two factors cancel each other out and make the C-implantation sample becomes more hydrophilic in general terms. Finally, cell culture demonstrates that negative ion-implantation is an effective method to improve the cell biocompatibility of RTV SR.

Fully Passive Wireless Acquisition of Neuropotentials

NASA Astrophysics Data System (ADS)

Schwerdt, Helen N.

The ability to monitor electrophysiological signals from the sentient brain is requisite to decipher its enormously complex workings and initiate remedial solutions for the vast amount of neurologically-based disorders. Despite immense advancements in creating a variety of instruments to record signals from the brain, the translation of such neurorecording instrumentation to real clinical domains places heavy demands on their safety and reliability, both of which are not entirely portrayed by presently existing implantable recording solutions. In an attempt to lower these barriers, alternative wireless radar backscattering techniques are proposed to render the technical burdens of the implant chip to entirely passive neurorecording processes that transpire in the absence of formal integrated power sources or powering schemes along with any active circuitry. These radar-like wireless backscattering mechanisms are used to conceive of fully passive neurorecording operations of an implantable microsystem. The fully passive device potentially manifests inherent advantages over current wireless implantable and wired recording systems: negligible heat dissipation to reduce risks of brain tissue damage and minimal circuitry for long term reliability as a chronic implant. Fully passive neurorecording operations are realized via intrinsic nonlinear mixing properties of the varactor diode. These mixing and recording operations are directly activated by wirelessly interrogating the fully passive device with a microwave carrier signal. This fundamental carrier signal, acquired by the implant antenna, mixes through the varactor diode along with the internal targeted neuropotential brain signals to produce higher frequency harmonics containing the targeted neuropotential signals. These harmonics are backscattered wirelessly to the external interrogator that retrieves and recovers the original neuropotential brain signal. The passive approach removes the need for internal power sources and may alleviate heat trauma and reliability issues that limit practical implementation of existing implantable neurorecorders.

Computational and Experimental Evaluations of a Novel Thermo-Brachytherapy Seed for Treatment of Solid Tumors

NASA Astrophysics Data System (ADS)

Warrell, Gregory R.

Hyperthermia has long been known as a radiation therapy sensitizer of high potential; however successful delivery of this modality and integrating it with radiation have often proved technically difficult. We present the dual-modality thermobrachytherapy (TB) seed, based on the ubiquitous low dose-rate (LDR) brachytherapy permanent implant, as a simple and effective combination of hyperthermia and radiation therapy. Heat is generated from a ferromagnetic or ferrimagnetic core within the seed, which produces Joule heating by eddy currents. A strategically-selected Curie temperature provides thermal self-regulation. In order to obtain a uniform and sufficiently high temperature distribution, additional hyperthermia-only (HT-only) seeds are proposed to be used in vacant spots within the needles used to implant the TB seeds; this permits a high seed density without the use of additional needles. Experimental and computational studies were done both to optimize the design of the TB and HT-only seeds and to quantitatively assess their ability to heat and irradiate defined, patient-specific targets. Experiments were performed with seed-sized ferromagnetic samples in tissue-mimicking phantoms heated by an industrial induction heater. The magnetic and thermal properties of the seeds were studied computationally in the finite element analysis (FEA) solver COMSOL Multiphysics, modelling realistic patient-specific seed distributions. These distributions were derived from LDR permanent prostate implants previously conducted at our institution; various modifications of the seeds' design were studied. The calculated temperature distributions were analyzed by generating temperature-volume histograms, which were used to quantify coverage and temperature homogeneity for a range of blood perfusion rates, as well as for a range of seed Curie temperatures and thermal power production rates. The impact of the interseed attenuation and scatter (ISA) effect on radiation dose distributions of this seed was also quantified by Monte Carlo studies in the software package MCNP5. Experimental and computational analyses agree that the proposed seeds may heat a defined target with safe and attainable seed spacing and magnetic field parameters. These studies also point to the use of a ferrite-based ferrimagnetic core within the seeds, a design that would deliver hyperthermia of acceptable quality even for the high rate of blood perfusion in prostate tissue. The loss of radiation coverage due to the ISA effect of distributions of TB and HT-only seeds may be rectified by slightly increasing the prescribed dose in standard dose superposition-based treatment planning software. A systematic approach of combining LDR prostate brachytherapy with hyperthermia is thus described, and its ability to provide sufficient and uniform temperature distributions in realistic patient-specific implants evaluated. Potential improvements to the previously reported TB seed design are discussed based on quantitative evaluation of its operation and performance.

High-fluence ion implantation in silicon carbide for fabrication of a compliant substrate

NASA Astrophysics Data System (ADS)

Lioubtchenko, Mikhail

GaN and related nitrides are promising materials for applications as UV/blue light emitters and in high-power, high-temperature electonic devices. Unfortunately, the vast potential of these materials cannot be realized effectively due to a large density of threading dislocations, arising from large lattice mismatch between GaN and utilized substrates. Therefore, a new approach to the heteroepitaxial growth is desirable, and a compliant substrate might help to remedy the situation. A modified model for the compliant substrate consisting of the compliant membrane glued to a thick handling substrate by a soft layer was proposed. We have chosen 6H-SiC as a starting substrate and ion implantation as a means of creating a buried layer. High fluence ion implantation of different species in 6H-SiC was performed at elevated temperatures and damage removal/accumulation was studied. It was found that temperatures around 1600°C are necessary to successfully recrystallize the radiation damage for Ti, Ga, Si and C implantations, but no damage removal was monitored for In implantation. In order to minimize the damage produced during ion implantation, it was decided to employ a multistep process in which each implantation step was followed by annealing. This approach was realized for 125 keV Ti++ and 300 keV Ga+ implantations up to a total dose of 1.8 x 1017 cm--2. Ti-implanted substrates were shown to retain good quality in the top layer, whereas Ga implantation preserves the quality of the near-surface region only at lower doses. The implanted species concentration was monitored after each step using Rutherford Backscattering (RBS). GaN films were grown on the prepared substrates and a control SiC sample by MOCVD. TEM and photoluminescence measurements have demonstrated that the quality of GaN films improves upon growth on compliant substrates.

Practical considerations for maximizing heat production in a novel thermobrachytherapy seed prototype

PubMed Central

Gautam, Bhoj; Warrell, Gregory; Shvydka, Diana; Subramanian, Manny; Ishmael Parsai, E.

2014-01-01

Purpose: A combination of hyperthermia and radiation in the treatment of cancer has been proven to provide better tumor control than radiation administered as a monomodality, without an increase in complications or serious toxicities. Moreover, concurrent administration of hyperthermia and radiation displays synergistic enhancement, resulting in greater tumor cell killing than hyperthermia and radiation delivered separately. The authors have designed a new thermobrachytherapy (TB) seed, which serves as a source of both radiation and heat for concurrent brachytherapy and hyperthermia treatments when implanted in solid tumors. This innovative seed, similar in size and geometry to conventional seeds, will have self-regulating thermal properties. Methods: The new seed's geometry is based on the standard BEST Model 2301 125I seed, resulting in very similar dosimetric properties. The TB seed generates heat when placed in an oscillating magnetic field via induction heating of a ferromagnetic Ni–Cu alloy core that replaces the tungsten radiographic marker of the standard Model 2301. The alloy composition is selected to undergo a Curie transition near 50 °C, drastically decreasing power production at higher temperatures and providing for temperature self-regulation. Here, the authors present experimental studies of the magnetic properties of Ni–Cu alloy material, the visibility of TB seeds in radiographic imaging, and the ability of seed prototypes to uniformly heat tissue to a desirable temperature. Moreover, analyses are presented of magnetic shielding and thermal expansion of the TB seed, as well as matching of radiation dose to temperature distributions for a short interseed distance in a given treatment volume. Results: Annealing the Ni–Cu alloy has a significant effect on its magnetization properties, increasing the sharpness of the Curie transition. The TB seed preserves the radiographic properties of the BEST 2301 seed in both plain x rays and CT images, and a preliminary experiment demonstrates thermal self-regulation and adequate heating of a tissue-mimicking phantom by seed prototypes. The effect of self-shielding of the seed against the external magnetic field is small, and only minor thermal stress is induced in heating of the seeds from room temperature to well above the seed operating temperature. With proper selection of magnetic field parameters, the thermal dose distribution of an arrangement of TB and hyperthermia-only seeds may be made to match with its radiation dose distribution. Conclusions: The presented analyses address several practical considerations for manufacturing of the proposed TB seeds and identify critical issues for the prototype implementation. The authors’ preliminary experiments demonstrate close agreement with the modeling results, confirming the feasibility of combining sources of heat and radiation into a single thermobrachytherapy seed. PMID:24506651

Practical considerations for maximizing heat production in a novel thermobrachytherapy seed prototype

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gautam, Bhoj; Warrell, Gregory; Shvydka, Diana

2014-02-15

Purpose: A combination of hyperthermia and radiation in the treatment of cancer has been proven to provide better tumor control than radiation administered as a monomodality, without an increase in complications or serious toxicities. Moreover, concurrent administration of hyperthermia and radiation displays synergistic enhancement, resulting in greater tumor cell killing than hyperthermia and radiation delivered separately. The authors have designed a new thermobrachytherapy (TB) seed, which serves as a source of both radiation and heat for concurrent brachytherapy and hyperthermia treatments when implanted in solid tumors. This innovative seed, similar in size and geometry to conventional seeds, will have self-regulatingmore » thermal properties. Methods: The new seed's geometry is based on the standard BEST Model 2301{sup 125}I seed, resulting in very similar dosimetric properties. The TB seed generates heat when placed in an oscillating magnetic field via induction heating of a ferromagnetic Ni–Cu alloy core that replaces the tungsten radiographic marker of the standard Model 2301. The alloy composition is selected to undergo a Curie transition near 50 °C, drastically decreasing power production at higher temperatures and providing for temperature self-regulation. Here, the authors present experimental studies of the magnetic properties of Ni–Cu alloy material, the visibility of TB seeds in radiographic imaging, and the ability of seed prototypes to uniformly heat tissue to a desirable temperature. Moreover, analyses are presented of magnetic shielding and thermal expansion of the TB seed, as well as matching of radiation dose to temperature distributions for a short interseed distance in a given treatment volume. Results: Annealing the Ni–Cu alloy has a significant effect on its magnetization properties, increasing the sharpness of the Curie transition. The TB seed preserves the radiographic properties of the BEST 2301 seed in both plain x rays and CT images, and a preliminary experiment demonstrates thermal self-regulation and adequate heating of a tissue-mimicking phantom by seed prototypes. The effect of self-shielding of the seed against the external magnetic field is small, and only minor thermal stress is induced in heating of the seeds from room temperature to well above the seed operating temperature. With proper selection of magnetic field parameters, the thermal dose distribution of an arrangement of TB and hyperthermia-only seeds may be made to match with its radiation dose distribution. Conclusions: The presented analyses address several practical considerations for manufacturing of the proposed TB seeds and identify critical issues for the prototype implementation. The authors’ preliminary experiments demonstrate close agreement with the modeling results, confirming the feasibility of combining sources of heat and radiation into a single thermobrachytherapy seed.« less

Practical considerations for maximizing heat production in a novel thermobrachytherapy seed prototype

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gautam, Bhoj; Warrell, Gregory; Shvydka, Diana

Purpose: A combination of hyperthermia and radiation in the treatment of cancer has been proven to provide better tumor control than radiation administered as a monomodality, without an increase in complications or serious toxicities. Moreover, concurrent administration of hyperthermia and radiation displays synergistic enhancement, resulting in greater tumor cell killing than hyperthermia and radiation delivered separately. The authors have designed a new thermobrachytherapy (TB) seed, which serves as a source of both radiation and heat for concurrent brachytherapy and hyperthermia treatments when implanted in solid tumors. This innovative seed, similar in size and geometry to conventional seeds, will have self-regulatingmore » thermal properties. Methods: The new seed's geometry is based on the standard BEST Model 2301{sup 125}I seed, resulting in very similar dosimetric properties. The TB seed generates heat when placed in an oscillating magnetic field via induction heating of a ferromagnetic Ni–Cu alloy core that replaces the tungsten radiographic marker of the standard Model 2301. The alloy composition is selected to undergo a Curie transition near 50 °C, drastically decreasing power production at higher temperatures and providing for temperature self-regulation. Here, the authors present experimental studies of the magnetic properties of Ni–Cu alloy material, the visibility of TB seeds in radiographic imaging, and the ability of seed prototypes to uniformly heat tissue to a desirable temperature. Moreover, analyses are presented of magnetic shielding and thermal expansion of the TB seed, as well as matching of radiation dose to temperature distributions for a short interseed distance in a given treatment volume. Results: Annealing the Ni–Cu alloy has a significant effect on its magnetization properties, increasing the sharpness of the Curie transition. The TB seed preserves the radiographic properties of the BEST 2301 seed in both plain x rays and CT images, and a preliminary experiment demonstrates thermal self-regulation and adequate heating of a tissue-mimicking phantom by seed prototypes. The effect of self-shielding of the seed against the external magnetic field is small, and only minor thermal stress is induced in heating of the seeds from room temperature to well above the seed operating temperature. With proper selection of magnetic field parameters, the thermal dose distribution of an arrangement of TB and hyperthermia-only seeds may be made to match with its radiation dose distribution. Conclusions: The presented analyses address several practical considerations for manufacturing of the proposed TB seeds and identify critical issues for the prototype implementation. The authors’ preliminary experiments demonstrate close agreement with the modeling results, confirming the feasibility of combining sources of heat and radiation into a single thermobrachytherapy seed.« less

Cell and defect behavior in lithium-counterdoped solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Mehta, S.; Swartz, C. K.

1984-01-01

Some n(+)/p cells in which lithium is introduced as a counterdopant, by ion-implantation, into the cell's boron-doped p-region were studied. To determine if the cells radiation resistance could be significantly improved by lithium counterdoping. Defect behavior was related to cell performance using deep level transient spectroscopy. Results indicate a significantly increased radiation resistance for the lithium counterdoped cells when compared to the boron doped 1 ohm-cm control cell. The increased radiation resistance of the lithium counterdoped cells is due to the complexing of lithium with divacancies and boron. It is speculated that complexing with oxygen and single vacancies also contributes to the increased radiation resistance. Counterdoping silicon with lithium results in a different set of defects.

Advances in the surface modification techniques of bone-related implants for last 10 years

PubMed Central

Qiu, Zhi-Ye; Chen, Cen; Wang, Xiu-Mei; Lee, In-Seop

2014-01-01

At the time of implanting bone-related implants into human body, a variety of biological responses to the material surface occur with respect to surface chemistry and physical state. The commonly used biomaterials (e.g. titanium and its alloy, Co–Cr alloy, stainless steel, polyetheretherketone, ultra-high molecular weight polyethylene and various calcium phosphates) have many drawbacks such as lack of biocompatibility and improper mechanical properties. As surface modification is very promising technology to overcome such problems, a variety of surface modification techniques have been being investigated. This review paper covers recent advances in surface modification techniques of bone-related materials including physicochemical coating, radiation grafting, plasma surface engineering, ion beam processing and surface patterning techniques. The contents are organized with different types of techniques to applicable materials, and typical examples are also described. PMID:26816626

Method of making silicon on insalator material using oxygen implantation

DOEpatents

Hite, Larry R.; Houston, Ted; Matloubian, Mishel

1989-01-01

The described embodiments of the present invention provide a semiconductor on insulator structure providing a semiconductor layer less susceptible to single event upset errors (SEU) due to radiation. The semiconductor layer is formed by implanting ions which form an insulating layer beneath the surface of a crystalline semiconductor substrate. The remaining crystalline semiconductor layer above the insulating layer provides nucleation sites for forming a crystalline semiconductor layer above the insulating layer. The damage caused by implantation of the ions for forming an insulating layer is left unannealed before formation of the semiconductor layer by epitaxial growth. The epitaxial layer, thus formed, provides superior characteristics for prevention of SEU errors, in that the carrier lifetime within the epitaxial layer, thus formed, is less than the carrier lifetime in epitaxial layers formed on annealed material while providing adequate semiconductor characteristics.

Radiation effects in astrophysical ices

NASA Astrophysics Data System (ADS)

Boduch, Philippe; Dartois, Emmanuel; de Barros, Ana L. F.; da Silveira, Enio F.; Domaracka, Alicja; Lv, Xue-Yang; Palumbo, Maria Elisabetta; Pilling, Sergio; Rothard, Hermann; Seperuelo Duarte, Eduardo; Strazzulla, Giovanni

2015-07-01

The interaction of heavy ions with astrophysical ices was studied at different beamlines of GANIL by infrared absorption spectroscopy. This allowed simulating in the laboratory the physico-chemical modifications induced in icy objects in space, exposed to radiation fields such as the solar wind, magnetospheric particles and interstellar cosmic rays. We briefly discuss sputtering, destruction and formation of molecules, amorphization and compaction, implantation, and finally the formation of organic molecules. This latter topic is related to the question of the initial conditions for the emergence of life.

Clinical Holistic Medicine: How to Recover Memory Without “Implanting” Memories in Your Patient

PubMed Central

Ventegodt, Søren; Kandel, Isack; Merrick, Joav

2007-01-01

Every therapeutic strategy and system teach us the philosophy of the treatment system to the patient, but often this teaching is subliminal and the philosophical impact must be seen as “implanted philosophy”, which gives distorted interpretations of past events called “implanted memories”. Based on the understanding of the connection between “implanted memory” and “implanted philosophy” we have developed a strategy for avoiding implanting memories arising from one of the seven most common causes of implanted memories in psychodynamic therapy: 1) Satisfying own expectancies, 2) pleasing the therapist, 3) transferences and counter transferences, 4) as source of mental and emotional order, 5) as emotional defence, 6) as symbol and 7) from implanted philosophy. Freud taught us that child sexuality is “polymorphously perverted”, meaning that all kinds of sexuality is present at least potentially with the little child; and in dreams consciousness often go back to the earlier stages of development, potentially causing all kinds of sexual dreams and fantasies, which can come up in therapy and look like real memories. The therapist working with psychodynamic psychotherapy, clinical holistic medicine, psychiatry, and emotionally oriented bodywork, should be aware of the danger of implanting philosophy and memories. Implanted memories and implanted philosophy must be carefully handled and de-learned before ending the therapy. In conclusion “clinical holistic medicine” has developed a strategy for avoiding implanting memories. PMID:17891319