scholarly journals Acoustic Localization of Bragg Peak Proton Beams for Hadrontherapy Monitoring

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 1971 ◽  
Author(s):  
Otero ◽  
Felis ◽  
Ardid ◽  
Herrero
Keyword(s):  
Bragg Peak ◽  
Heavy Particle ◽  
Patient Positioning ◽  
Spot Size ◽  
Simulation Studies ◽  
Acoustic Localization ◽  
Energy Beam ◽  
Acoustic Technologies ◽  
High Doses ◽  
Anatomical Parameters

Hadrontherapy makes it possible to deliver high doses of energy to cancerous tumors by using the large energy deposition in the Bragg-peak. However, uncertainties in the patient positioning and/or in the anatomical parameters can cause distortions in the calculation of the dose distribution. In order to maximize the effectiveness of heavy particle treatments, an accurate monitoring system of the deposited dose depending on the energy, beam time, and spot size is necessary. The localized deposition of this energy leads to the generation of a thermoacoustic pulse that can be detected using acoustic technologies. This article presents different experimental and simulation studies of the acoustic localization of thermoacoustic pulses captured with a set of sensors around the sample. In addition, numerical simulations have been done where thermo-acoustic pulses are emitted for the specific case of a proton beam of 100 MeV.

scholarly journals Acoustic Location of Bragg Peak for Hadrontherapy Monitoring

Proceedings ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 6
Author(s):  
Jorge Otero ◽  
Miguel Ardid ◽  
Ivan Felis ◽  
Alicia Herrero
Keyword(s):  
Energy Deposition ◽  
Bragg Peak ◽  
Heavy Particle ◽  
Patient Positioning ◽  
Spot Size ◽  
Simulation Studies ◽  
Acoustic Localization ◽  
Acoustic Technologies ◽  
High Doses ◽  
Anatomical Parameters

Hadrontherapy makes it possible to deliver high doses of energy to cancerous tumors by using the large energy deposition in the Bragg-peak. However, uncertainties in the patient positioning and or in the anatomical parameters can cause distortions in the calculation of the dose distribution. In order to maximize the effectiveness of heavy particle treatments, an accurate monitoring system of the deposited dose depending on the energy, the beam time, and the spot size is necessary. The localized deposition of this energy leads to the generation of a thermoacoustic pulse that can be detected using acoustic technologies. This article presents different experimental and simulation studies of the acoustic localization of thermoacoustic pulses by generating similar signals that have been captured with a set of sensors around the samples. In addition, numerical simulations have been done where thermoacoustic pulses are emitted for the specific case of a proton beam of 100 MeV.

scholarly journals Robotic Systems in Radiotherapy and Radiosurgery

2022 ◽  
Author(s):  
Stefan Gerlach ◽  
Alexander Schlaefer
Keyword(s):  
Medical Devices ◽  
Patient Positioning ◽  
Target Motion ◽  
Robotic Systems ◽  
Beam Source ◽  
Target Region ◽  
Safe Delivery ◽  
Research Context ◽  
Research Systems ◽  
High Doses

Abstract Purpose of Review This review provides an overview of robotic systems in radiotherapy and radiosurgery, with a focus on medical devices and recently proposed research systems. We summarize the key motivation for using robotic systems and illustrate the potential advantages. Recent Findings. Robotic systems have been proposed for a variety of tasks in radiotherapy, including the positioning of beam source, patients, and imaging devices. A number of systems are cleared for use in patients, and some are widely used, particularly for beam and patient positioning. Summary The need for precise and safe delivery of focused high doses to the target region motivates the use of robots in radiotherapy. Flexibility in the arrangement of beams and the ability to compensate for target motion are key advantages of robotic systems. While robotic patient couches are widely used and robotic beam positioning is well established, brachytherapy robots are mostly considered in a research context.

scholarly journals On-line range verification for proton beam therapy using spherical ionoacoustic waves with resonant frequency

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Taisuke Takayanagi ◽  
Tomoki Uesaka ◽  
Yuta Nakamura ◽  
Mehmet Burcin Unlu ◽  
Yasutoshi Kuriyama ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Proton Beam ◽  
Patient Positioning ◽  
Proton Beam Therapy ◽  
Simulation Studies ◽  
Clinical Dose ◽  
On Line ◽  
Verification Methodology ◽  
Beam Range ◽  
Range Verification

AbstractIn contrast to conventional X-ray therapy, proton beam therapy (PBT) can confine radiation doses to tumours because of the presence of the Bragg peak. However, the precision of the treatment is currently limited by the uncertainty in the beam range. Recently, a unique range verification methodology has been proposed based on simulation studies that exploit spherical ionoacoustic waves with resonant frequency (SPIREs). SPIREs are emitted from spherical gold markers in tumours initially introduced for accurate patient positioning when the proton beam is injected. These waves have a remarkable property: their amplitude is linearly correlated with the residual beam range at the marker position. Here, we present proof-of-principle experiments using short-pulsed proton beams at the clinical dose to demonstrate the feasibility of using SPIREs for beam-range verification with submillimetre accuracy. These results should substantially contribute to reducing the range uncertainty in future PBT applications.

Ionoacoustics: A new direct method for range verification

2015 ◽  
Vol 30 (17) ◽  
pp. 1540025 ◽  
Author(s):  
Katia Parodi ◽  
Walter Assmann
Keyword(s):  
Bragg Peak ◽  
Direct Method ◽  
Organs At Risk ◽  
Ion Beam ◽  
Patient Positioning ◽  
Nuclear Interaction ◽  
Ion Beams ◽  
Verification Techniques ◽  
Range Verification

The superior ballistic properties of ion beams may offer improved tumor-dose conformality and unprecedented sparing of organs at risk in comparison to other radiation modalities in external radiotherapy. However, these advantages come at the expense of increased sensitivity to uncertainties in the actual treatment delivery, resulting from inaccuracies of patient positioning, physiological motion and uncertainties in the knowledge of the ion range in living tissue. In particular, the dosimetric selectivity of ion beams depends on the longitudinal location of the Bragg peak, making in vivo knowledge of the actual beam range the greatest challenge to full clinical exploitation of ion therapy. Nowadays, in vivo range verification techniques, which are already, or close to, being investigated in the clinical practice, rely on the detection of the secondary annihilation photons or prompt gammas, resulting from nuclear interaction of the primary ion beam with the irradiated tissue. Despite the initial promising results, these methods utilize a not straightforward correlation between nuclear and electromagnetic processes, and typically require massive and costly instrumentation. On the contrary, the long-term known, yet only recently revisited process of "ionoacoustics", which is generated by local tissue heating especially at the Bragg peak, may offer a more direct approach to in vivo range verification, as reviewed here.

Beam simulation studies of ECR beam extraction and low energy beam transport for FRIB

2016 ◽  
Vol 87 (2) ◽  
pp. 02B919 ◽  
Author(s):  
Haitao Ren ◽  
Eduard Pozdeyev ◽  
Steven M. Lund ◽  
Guillaume Machicoane ◽  
Xiaoyu Wu ◽  
...  
Keyword(s):  
Low Energy ◽  
Beam Extraction ◽  
Simulation Studies ◽  
Beam Transport ◽  
Energy Beam

Ultrastructural Localization of Acetylcholinesterase in the Arcuate Nucleus and Median Eminence of the Rat

1977 ◽  
Vol 35 ◽  
pp. 440-441
Author(s):  
K.A. Carson ◽  
C.B. Nemeroff ◽  
M.S. Rone ◽  
J.S. Kizer ◽  
J.S. Hanker
Keyword(s):  
Choline Acetyltransferase ◽  
Median Eminence ◽  
Arcuate Nucleus ◽  
Cholinergic Neurons ◽  
Ultrastructural Localization ◽  
Male Rats ◽  
Neonatal Rats ◽  
Good Marker ◽  
Chemical Studies ◽  
High Doses

Biochemical, physiological, pharmacological, and more recently enzyme histo- chemical data have indicated that cholinergic circuits exist in the hypothalamus. Ultrastructural correlates of these pathways such as acetylcholinesterase (AchE) positive neurons in the arcuate nucleus (ARC) and stained terminals in the median eminence (ME) have yet to be described. Initial studies in our laboratories utilizing chemical lesioning and microdissection techniques coupled with microchemical and light microscopic enzyme histo- chemical studies suggested the existence of cholinergic neurons in the ARC which project to the ME (1). Furthermore, in adult male rats with Halasz deafferentations (hypothalamic islands composed primarily of the isolated ARC and the ME) choline acetyltransferase (ChAc) activity, a good marker for cholinergic neurons, was not significantly reduced in the ME and was only somewhat reduced in the ARC (2). Treatment of neonatal rats with high doses of monosodium 1-glutamate (MSG) results in a lesion largely restricted to the neurons of the ARC.

Remarks on the application of backscattered electron imaging (BEI) to the scanning electron microscopy (SEM) of biological structures

1983 ◽  
Vol 41 ◽  
pp. 484-487
Author(s):  
Etienne de Harven
Keyword(s):  
High Resolution ◽  
Incident Beam ◽  
Spot Size ◽  
Primary Electron ◽  
Critical Point Drying ◽  
Cell Shapes ◽  
High Resolution Images ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
Scanning Electron

Biological ultrastructures have been extensively studied with the scanning electron microscope (SEM) for the past 12 years mainly because this instrument offers accurate and reproducible high resolution images of cell shapes, provided the cells are dried in ways which will spare them the damage which would be caused by air drying. This can be achieved by several techniques among which the critical point drying technique of T. Anderson has been, by far, the most reproducibly successful. Many biologists, however, have been interpreting SEM micrographs in terms of an exclusive secondary electron imaging (SEI) process in which the resolution is primarily limited by the spot size of the primary incident beam. in fact, this is not the case since it appears that high resolution, even on uncoated samples, is probably compromised by the emission of secondary electrons of much more complex origin.When an incident primary electron beam interacts with the surface of most biological samples, a large percentage of the electrons penetrate below the surface of the exposed cells.

A High Resolution Scanning Microscope

1968 ◽  
Vol 26 ◽  
pp. 356-357
Author(s):  
A. V. Crewe ◽  
J. Wall ◽  
L. M. Welter
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Spherical Aberration ◽  
Focal Length ◽  
Spot Size ◽  
Emission Source ◽  
Field Of View ◽  
Scanning Microscope ◽  
Magnetic Lens ◽  
High Quality

A scanning microscope using a field emission source has been described elsewhere. This microscope has now been improved by replacing the single magnetic lens with a high quality lens of the type described by Ruska. This lens has a focal length of 1 mm and a spherical aberration coefficient of 0.5 mm. The final spot size, and therefore the microscope resolution, is limited by the aberration of this lens to about 6 Å.The lens has been constructed very carefully, maintaining a tolerance of + 1 μ on all critical surfaces. The gun is prealigned on the lens to form a compact unit. The only mechanical adjustments are those which control the specimen and the tip positions. The microscope can be used in two modes. With the lens off and the gun focused on the specimen, the resolution is 250 Å over an undistorted field of view of 2 mm. With the lens on,the resolution is 20 Å or better over a field of view of 40 microns. The magnification can be accurately varied by attenuating the raster current.

Image registration with a computer driven S.T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 98-99
Author(s):  
A.M.H. Schepman ◽  
J.A.P. van der Voort ◽  
J.E. Mellema
Keyword(s):  
Spot Size ◽  
Scanning Transmission Electron Microscope ◽  
Small Computer ◽  
Structural Studies ◽  
Area Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Specimen Area ◽  
On Line ◽  
Minimum Distances

A Scanning Transmission Electron Microscope (STEM) was coupled to a small computer. The system (see Fig. 1) has been built using a Philips EM400, equipped with a scanning attachment and a DEC PDP11/34 computer with 34K memory. The gun (Fig. 2) consists of a continuously renewed tip of radius 0.2 to 0.4 μm of a tungsten wire heated just below its melting point by a focussed laser beam (1). On-line operation procedures were developped aiming at the reduction of the amount of radiation of the specimen area of interest, while selecting the various imaging parameters and upon registration of the information content. Whereas the theoretical limiting spot size is 0.75 nm (2), routine resolution checks showed minimum distances in the order 1.2 to 1.5 nm between corresponding intensity maxima in successive scans. This value is sufficient for structural studies of regular biological material to test the performance of STEM over high resolution CTEM.

Ultra-spatially resolved synchrotron powered FT-IR microspectroscopy of individual cells of biological material

1995 ◽  
Vol 53 ◽  
pp. 884-885
Author(s):  
David L. Wetzel ◽  
John A. Reffner ◽  
Gwyn P. Williams
Keyword(s):  
Thermal Noise ◽  
Spot Size ◽  
Acquisition Time ◽  
Thermal Source ◽  
Signal To Noise ◽  
Spatially Resolved ◽  
Good Spatial Resolution ◽  
Small Spot ◽  
Ft Ir ◽  
Ir Microspectroscopy

Synchrotron radiation is 100 to 1000 times brighter than a thermal source such as a globar. It is not accompanied with thermal noise and it is highly directional and nondivergent. For these reasons, it is well suited for ultra-spatially resolved FT-IR microspectroscopy. In efforts to attain good spatial resolution in FT-IR microspectroscopy with a thermal source, a considerable fraction of the infrared beam focused onto the specimen is lost when projected remote apertures are used to achieve a small spot size. This is the case because of divergence in the beam from that source. Also the brightness is limited and it is necessary to compromise on the signal-to-noise or to expect a long acquisition time from coadding many scans. A synchrotron powered FT-IR Microspectrometer does not suffer from this effect. Since most of the unaperatured beam’s energy makes it through even a 12 × 12 μm aperture, that is a starting place for aperture dimension reduction.

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