Automatic Beam Research Articles

Patterns of utilization and clinical adoption of 0.35 Tesla MR-guided radiation therapy in the United States – Understanding the transition to adaptive, ultra-hypofractionated treatments

Purpose/ObjectiveMagnetic resonance-guided radiation therapy (MRgRT) utilization is rapidly expanding worldwide, driven by advanced capabilities including continuous intrafraction visualization, automatic triggered beam delivery, and on-table adaptive replanning (oART). Our objective was to describe patterns of 0.35Tesla(T)-MRgRT (MRIdian) utilization in the United States (US) among early adopters of this novel technology. Materials/MethodsAnonymized administrative data from all US MRIdian treatment systems were extracted for patients completing treatment from 2014 to 2020. Detailed treatment information was available for all MRIdian linear accelerator (linac) systems and some cobalt systems. ResultsSeventeen systems at 16 centers delivered 5736 courses and 36,389 fractions (fraction details unavailable for 1223 cobalt courses), of which 21.1% were adapted. Ultra-hypofractionation (UHfx) (1–5 fractions) was used in 70.3% of all courses. At least one adaptive fraction was used for 38.5% of courses (average 1.7 adapted fractions/course), with higher oART use in UHfx dose schedules (47.7% of courses, average 1.9 adapted fractions per course). The most commonly treated organ sites were pancreas (20.7%), liver (16.5%), prostate (12.5%), breast (11.5%), and lung (9.4%). Temporal trends show a compounded annual growth rate (CAGR) of 59.6% in treatment courses delivered, with a dramatic increase in use of UHfx to 84.9% of courses in 2020 and similar increase in use of oART to 51.0% of courses. ConclusionsThis is the first comprehensive study reporting patterns of utilization among early adopters of MRIdian in the US. Intrafraction MR image-guidance, advanced motion management, and increasing adoption of adaptive radiation therapy has led to a substantial transition to ultra-hypofractionated regimens. 0.35 T-MRgRT has been predominantly used to treat abdominal and pelvic tumors with increasing use of on-table adaptive replanning, which represents a paradigm shift in radiation therapy.

Stereotactic MR-Guided On-Table Adaptive Radiation Therapy (SMART) for Patients with Borderline or Locally Advanced Pancreatic Cancer: Primary Endpoint Outcomes of a Prospective Phase II Multi-Center International Trial

<h3>Purpose/Objective(s)</h3> Retrospective studies demonstrate that ablative stereotactic MR-guided on-table adaptive radiation therapy (SMART) achieves favorable local control (LC) and overall survival (OS) with limited grade 3+ toxicity compared to historical non-ablative outcomes for locally advanced and borderline resectable pancreatic cancer (LAPC/BRPC). We conducted an international multi-center single-arm phase 2 trial of ablative 5-fraction SMART for LAPC/BRPC. <h3>Materials/Methods</h3> Subjectswere required to have biopsy-confirmed adenocarcinoma, receive ≥3 months of chemotherapy, have no distant metastasis and CA19-9 ≤500 U/mL. SMART was delivered on a 0.35T MR-⁶⁰Co or MR-linac system prescribed to 50 Gy in 5 fractions (biologically effective dose₁₀ [BED₁₀]=100 Gy) using continuous intrafraction cine-MRI, soft tissue tracking, and automatic beam gating. The original plan was recomputed onto the daily anatomy and if that plan would not have met constraints, on-table adaptive replanning using an isotoxicity approach was performed. The primary objective was to demonstrate <15.8% acute grade 3+ gastrointestinal (GI) toxicity definitely related to SMART measured through 90 days and evaluated according to Common Terminology Criteria for Adverse Events v5.0 (CTCAE). All patients have completed 90-day follow-up. Secondary objectives included OS, distant progression free survival (DPFS), and patient-reported quality of life. <h3>Results</h3> 136 patients across 13 sites were enrolled between 2019-2021. Mean age was 65.7 years. Head of pancreas lesions were most common (66.9%; n=91). 43.4% (n=59) had BRPC, 56.6% (n=77) LAPC. Mean induction chemotherapy duration was 155.7 days, typically with FOLFIRINOX 65.4% (n=89) or gemcitabine doublet 16.9% (n=23). Mean CA19-9 after induction chemotherapy was 71.7 U/mL. On-table adaptive replanning was used for 93.1% of fractions. SMART was delivered in consecutive days (56.6%) or every other day (43.4%). Median follow-up was 16.4 months and 8.8 months from diagnosis and SMART, respectively. 31.6% (n=43) had surgery after SMART. The incidence of acute grade 3+ GI toxicity definitely and probably related to SMART were 0% and 2.2% (n=3), respectively. 1-year LC and DPFS from SMART were 82.9% and 50.6%, respectively. 1-year OS was 93.9% from diagnosis and 65.0% from SMART. <h3>Conclusion</h3> This is the first prospective, multi-institutional study of ablative SMART with prescribed BED₁₀ of 100 Gy delivered in 5 fractions for BRPC/LAPC. The primary objective was met, signaling that further prospective evaluation of ablative SMART for BRPC/LAPC is warranted with a focus on long-term LC and OS compared to chemotherapy alone.

Dosimetric Implications of Margin-Reduced MRI-Guided Stereotactic Body Radiotherapy to the Prostate Bed Following Radical Prostatectomy: Post-Hoc Analysis of a Phase II Study

<h3>Purpose/Objective(s)</h3> Due to the highly deformable and mobile nature of the target volume and adjacent organs at risk (OARs), generous planning target volume (PTV) margins have historically been used in the context of radiotherapy after radical prostatectomy. MRI-guided radiotherapy systems have improved on-board imaging capabilities and the ability to perform automatic beam holds based on pre-specified structures. Herein, we evaluate the dosimetric implications of interfraction variations in the clinical target volumes (CTV) and OARs in patients receiving margin-reduced MRI-guided stereotactic body radiotherapy (SBRT) to the prostate bed. <h3>Materials/Methods</h3> 31 consecutive patients received MRI-guided SBRT to the prostate bed (30 – 34 Gy in 5 fractions) without adaptive planning on a phase II study. The OAR volumes, CTV, and PTV (created using a 3 mm isotropic expansion of the CTV) were retrospectively contoured on on-board 0.35T MRIs obtained prior to each fraction (n=155). Geometric comparisons were made between the initial planning contours and the 5 daily contours for each patient using change in volume and Dice similarity coefficient (DSC) calculations. Coverage of the CTV and PTV was assessed (CTV V95% >93% and PTV V95% >90%), as were bladder and rectal dose constraints (Bladder Dmax <36.7 Gy, Bladder V32.5 Gy <35%, Rectum Dmax <36.7 Gy, Rectum V27.5 Gy <45%, Rectum 32.5 Gy <30%, and Rectal Wall V24 <50%). <h3>Results</h3> The median change in volume was -24.5% (interquartile range [IQR], -35.5 – -2.2%) for the bladder, 6.95% (IQR, -6.94 – 23.0%) for the rectum, -0.2% (IQR, -8.3 – 8.7%) for the rectal wall, 0.48% (IQR, -3.87 – 7.6%) for the CTV, and -0.48% (IQR, -5.12 – 6.53%) for the PTV. The median DSC was 0.79 (IQR, 0.73 – 0.84) for the bladder, 0.76 (IQR, 0.69 – 0.81) for the rectum, 0.35 (IQR, 0.28 – 0.44) for the rectal wall, 0.89 (IQR, 0.83 – 0.93) for the CTV, and 0.90 (IQR, 0.87 – 0.95) for the PTV. 145/155 fractions (93.5%) met the CTV V95% >93% target and 134/155 fractions (86.5%) met both the CTV V95% >93% and PTV V95% >90% targets. When calculated over 5 cumulative fractions, 29/31 patients (93.5%) met the CTV goal of V95% >93%. 62/155 fractions (40%) failed at least one OAR constraint. The mean number of fractions per patient that failed at least one OAR constraint was 2/5 (median, 1; range, 0 – 5). <h3>Conclusion</h3> With MRI-guidance, a reduction of the PTV margin to 3 mm isotropically allows for adequate CTV coverage in over 90% of patients without the need for adaptive planning. However, OAR constraints are not met in 40% of delivered fractions despite meeting all dose constraints at the time of treatment planning. Online dose prediction and, if indicated, adaptive radiotherapy can optimize this to allow for improved OAR protection and potentially allow for further reductions in the PTV expansion while maintaining adequate CTV coverage.

On-line adaptive and real-time intrafraction motion management of spine-SBRT on an MR-linac

Purpose: The superior soft-tissue contrast of MRI-guided radiotherapy offers enhanced localization accuracy of the spinal cord in spine Stereotactic Body Radiotherapy (SBRT). This work includes a planning study for spine-SBRT on an MR-Linac. Additionally, a patient with spine metastasis was treated using an adaptive radiation therapy workflow. We report our initial experience of targeting accuracy, image-guided localization, on-line adaptive planning, and treatment with real-time intrafraction imaging with automatic beam gating.Methods: Six spine-SBRT patients were retrospectively re-planned to 18 Gy in 1-fraction on a commercial, Monte Carlo-based MR-Linac treatment planning system. Plans were generated using 9–13 step-and-shoot intensity-modulated radiation therapy 6 MV-flattening filter free beams and optimized to achieve plan quality criteria recommended by RTOG-0631. One thoracic vertebral body clinical case was treated to 27 Gy in 3-fractions utilizing ART, where daily anatomical changes were accounted for via re-planning and treatment in an on-line manner to account for limited ability to correct rotational setup uncertainties.Results: Plans met all critical-tissue constraints outlined in RTOG-0631 and AAPM Task Group-101, while covering 90% of the target with the prescription dose. Clinically, visibility of the spinal cord allowed for patient setup focusing on spinal cord-alignment. Utilization of the online ART workflow, while re-contouring the target and spinal cord, enabled an increase in prescription dose coverage from 89 to 95% in two of three fractions while maintaining acceptable doses to organs-at-risk. Real-time MR-cine imaging demonstrated sufficient quality for the automatic beam gating algorithm to provide intrafraction motion management of the spinal canal utilizing a 3.0 mm gating boundary and 1–2% region of excursion allowance, in the sagittal plane. A decrease in coverage, below the 95% threshold was noted in post-treatment volumetric imaging due to lateral movement not observed during real-time gating.Conclusion: Achieved plan quality and deliverability was within accepted standards. MR-guidance with an on-line ART workflow offered increased accuracy in the localization of the spinal cord at the time of treatment to enhance both tissue sparing and target volume coverage. Increased spatial resolution of cine-images, and tracking in three-dimensions would be beneficial for future spine-SBRT treatments on the MR-Linac.

Clinical adoption patterns of 0.35 Tesla MR-guided radiation therapy in Europe and Asia

BackgroundMagnetic resonance-guided radiotherapy (MRgRT) utilization is rapidly expanding, driven by advanced capabilities including better soft tissue imaging, continuous intrafraction target visualization, automatic triggered beam delivery, and the availability of on-table adaptive replanning. Our objective was to describe patterns of 0.35 Tesla (T)-MRgRT utilization in Europe and Asia among early adopters of this novel technology.MethodsAnonymized administrative data from all 0.35T-MRgRT treatment systems in Europe and Asia were extracted for patients who completed treatment from 2015 to 2020. Detailed treatment information was analyzed for all MR-linear accelerators (linac) and -cobalt systems.ResultsFrom 2015 through the end of 2020, there were 5796 completed treatment courses delivered in 46,389 individual fractions. 23.5% of fractions were adapted. Ultra-hypofractionated (UHfx) dose schedules (1–5 fractions) were delivered for 63.5% of courses, with 57.8% of UHfx fractions adapted on-table. The most commonly treated tumor types were prostate (23.5%), liver (14.5%), lung (12.3%), pancreas (11.2%), and breast (8.0%), with increasing compound annual growth rates (CAGRs) in numbers of courses from 2015 through 2020 (pancreas: 157.1%; prostate: 120.9%; lung: 136.0%; liver: 134.2%).ConclusionsThis is the first comprehensive study reporting patterns of utilization among early adopters of a 0.35T-MRgRT system in Europe and Asia. Intrafraction MR image-guidance, advanced motion management, and increasing adoption of on-table adaptive RT have accelerated a transition to UHfx regimens. MRgRT has been predominantly used to treat tumors in the upper abdomen, pelvis and lungs, and increasingly with adaptive replanning, which is a radical departure from legacy radiotherapy practices.

Optimization of FLASH proton beams using a track-repeating algorithm.

Radiation with high dose rate (FLASH) has shown to reduce toxicities to normal tissues around the target and maintain tumor control with the same amount of dose compared to conventional radiation. This phenomenon has been widely studied in electron therapy, which is often used for shallow tumor treatment. Proton therapy is considered a more suitable treatment modality for deep-seated tumors. The feasibility of FLASH proton therapy has recently been demonstrated by a series of pre- and clinical trials. One of the challenges is to efficiently generate wide enough dose distributions in both lateral and longitudinal directions to cover the entire tumor volume. The goal of this paper is to introduce a set of automatic FLASH proton beam optimization algorithms developed recently. To develop a fast and efficient optimizer for the design of a passive scattering proton FLASH radiotherapy delivery at The University of Texas MD Anderson Proton Therapy Center, based on the fast dose calculator (FDC). A track-repeating algorithm, FDC, was validated versus Geant4 simulations and applied to calculate dose distributions in various beamline setups. The design of the components was optimized to deliver homogeneous fields with well-defined diameters between 11.0 and 20.5mm, as well as a spread-out Bragg peak (SOBP) with modulations between 8.5 and 39.0mm. A ridge filter, a high-Z material scatterer, and a collimator with range compensator were inserted in the beam path, and their shapes and sizes were optimized to spread out the Bragg peak, widen the beam, and reduce the penumbra. The optimizer was developed and tested using two proton energies (87.0 and 159.5MeV) in a variety of beamline arrangements. Dose rates of the optimized beams were estimated by scaling their doses to those of unmodified beams. The optimized 87.0-MeV beams, with a distance from the beam pipe window to the phantom surface (window-to-surface distance [WSD]) of 550mm, produced an 8.5-mm-wide SOBP (proximal 90% to distal 90% of the maximum dose); 14.5, 12.0, and 11.0-mm lateral widths at the 50%, 80%, and 90% dose location, respectively; and a 2.5-mm penumbra from 80% to 20% in the lateral profile. The 159.5-MeV beam had an SOBP of 39.0mm and lateral widths of 20.5, 15.0, and 12.5mm at 50%, 80%, and 90% dose location, respectively, when the WSD was 550mm. Wider lateral widths were obtained with increased WSD. The SOBP modulations changed when the ridge filters with different characteristics were inserted. Dose rates on the beam central axis for all optimized beams (other than the 87.0-MeV beam with 2000-mm WSD) were above that needed for the FLASH effect threshold (40Gy/s) except at the very end of the depth dose profile scaling with a dose rate of 1400Gy/s at the Bragg peak in the unmodified beams. The optimizer was able to instantly design the individual beamline components for each of the beamline setups, without the need of time intensive iterative simulations. An efficient system, consisting of an optimizer and an FDC have been developed and validated in a variety of beamline setups, comprising two proton energies, several WSDs, and SOBPs. The set of automatic optimization algorithms produces beam shaping element designs efficiently and with excellent quality.

Toward automatic beam angle selection for pencil‐beam scanning proton liver treatments: A deep learning–based approach

Dose deposition characteristics of proton radiation can be advantageous over photons. Proton treatment planning, however, poses additional challenges for the planners. Proton therapy is usually delivered with only a small number of beam angles, and the quality of a proton treatment plan is largely determined by the beam angles employed. Finding the optimal beam angles for a proton treatment plan requires time and experience, motivating the investigation of automatic beam angle selection methods. A deep learning-based approach to automatic beam angle selection is proposed for the proton pencil-beam scanning treatment planning of liver lesions. We cast beam-angle selection as a multi-label classification problem. To account for angular boundary discontinuity, the underlying convolution neural network is trained with the proposed Circular Earth Mover's Distance-based regularization and multi-label circular-smooth label technique. Furthermore, an analytical algorithm emulating proton treatment planners' clinical practice is employed in post-processing to improve the output of the model. Forty-nine patients that received proton liver treatments between 2017 and 2020 were randomly divided into training (n=31), validation (n=7), and test sets (n=11). AI-selected beam angles were compared with those angles selected by human planners, and the dosimetric outcome was investigated by creating plans using knowledge-based treatment planning. For 7 of the 11 cases in the test set, AI-selected beam angles agreed with those chosen by human planners to within 20° (median angle difference=10°; mean=18.6°). Moreover, out of the total 22 beam angles predicted by the model, 15 (68%) were within 10° of the human-selected angles. The high correlation in beam angles resulted in comparable dosimetric statistics between proton treatment plans generated using AI- and human-selected angles. For the cases with beam angle differences exceeding 20°, the dosimetric analysis showed similar plan quality although with different emphases on organ-at-risk sparing. This pilot study demonstrated the feasibility of a novel deep learning-based beam angle selection technique. Testing on liver cancer patients showed that the resulting plans were clinically viable with comparable dosimetric quality to those using human-selected beam angles. In tandem with auto-contouring and knowledge-based treatment planning tools, the proposed model could represent a pathway for nearly fully automated treatment planning in proton therapy.

Design of 2×250kN large-span hoist hydraulic automatic grabbing beam

In water conservancy projects, automatic grabbing beams, as an important supporting equipment of mobile hoisting equipment, are widely used to improve the performance of operating gates and trash racks. This paper takes the hydraulic automatic grabbing beam of the 2 × 250kN large-span hoist at Baihetan Hydropower Station as an example. The design of the hydraulic automatic grabbing beam for the hoist is systematically analyzed, combined with engineering examples, and the most unfavorable conditions are used. As a result of the calculation, some design parameters of the long-span grab beam were obtained. The test results show that all performance indicators can meet the design requirements and relevant standard requirements.

6G Indoor Network Enabled by Photonics- and Electronics-Based sub-THz Technology

We propose an indoor network with a sub-terahertz- band wireless link for 6G applications. In our proposed indoor network, an optical hub unit (OHU) that controls the entire system is optically linked to THz remote nodes (RNs) over optical distribution fibers. The THz RNs communicate with the user equipment through a sub-THz wireless link. The function of the THz RNs is to provide an interface between the optical link and the sub-THz wireless link. For downlink transmission, a photonics-based sub-THz-band signal generation method is adopted to take advantage of the broadband characteristics of the optical components. An electronics-based sub-THz mixer is also used for uplink transmission because of its cost-effectiveness and low energy consumption. A digital signal processor (DSP) is designed to recover the original transmitted baseband signal. The DSP provides frequency offset compensation over a wide frequency range and reduces the probability of cyclic slip. The performance of the proposed system was investigated experimentally with commercially available optical&#x002F;electrical components. We demonstrate 100 Gb&#x002F;s 2.5-m wireless transmission with a 16-quadrature amplitude modulation (16-QAM) signal for configuring the downlink. The optical transmission distance was set to 10 km, and the power penalty measured by optical transmission was negligible. We also investigated the scalability and tunability of the photonics-based sub-THz transmitter to confirm the upgradability of our proposed indoor network to consider future capacity expansion. To establish an uplink, a 25 Gb&#x002F;s 1.5-m wireless transmission with a quadrature phase shift keying (QPSK) signal was employed. A directly modulated laser was used for cost-effective optical transmission. Unlike downstream transmission, a measured bit error rate (BER) penalty caused by the optical transmission was observed. This is due to the interplay between the frequency chirp of the directly modulated laser and the chromatic dispersion in the fiber. Despite this penalty, BERs less than the soft-decision forward error correction (FEC) threshold (2&#x00A0;&#x00D7;&#x00A0;10^&#x2212;2) with 20&#x0025; overhead were achieved. We discuss several remaining technical challenges in real-field deployment. These include THz Tx power improvement, photonic integration, reducing form-factor, polarization insensitivity, and automatic beam steering. Our recent efforts to address these issues are also introduced and examined.

Dose-Escalated Magnetic Resonance Image–Guided Abdominopelvic Reirradiation With Continuous Intrafraction Visualization, Soft Tissue Tracking, and Automatic Beam Gating

PurposeCompared with computed tomography, magnetic resonance (MR) image guidance offers significant advantages for radiation therapy (RT) that may be particularly beneficial for reirradiation (reRT). However, clinical outcomes of MR-guided reRT are not well described in the published literature. Methods and MaterialsWe performed a single-institution retrospective safety and efficacy analysis of reRT patients treated on the MRIdian Linac to targets within the abdomen or pelvis using continuous intrafraction MR-based motion management with automatic beam triggering. Fiducial markers were not used. ResultsWe evaluated 11 patients who received prior RT to a median of 50 Gy (range, 30-58.8 Gy) in 25 fractions (range, 5-28 fractions). The median interval to reRT was 26.8 months. The most frequently retreated sites were nodal metastases (36.4%) and pancreatic cancer (27.3%). The median reRT dose was 40 Gy (range, 25-54 Gy) in 6 fractions (range, 5-36 fractions); ultrahypofractionation (63.6%) was more common than hyperfractionation (36.4%). Daily on-table adaptive replanning was used for 3 patients (27.3%). With a median of 14 months’ follow-up from reRT completion (range, 6-32 months), the median and 1-year freedom from local progression were 29 months and 88.9%, respectively, and the median and 1-year overall survival were 17.5 months and 70.0%, respectively. One patient (9.1%) experienced acute grade 2 toxic effects; there were no acute or late treatment-related toxic effects of grade 3 or greater. ConclusionsMagnetic resonance–guided reRT appeared to be feasible and may facilitate safe dose escalation. Additional follow-up is needed to better assess long-term efficacy and late toxic effects. Prospective evaluation of this novel treatment strategy is warranted.

Patterns of Utilization and Clinical Adoption of 0.35 MR-Guided Radiation Therapy in the United States — Understanding the Transition to Adaptive, Ultra-Hypofractionated Treatments

Purpose/Objective(s)Magnetic resonance imaging-guided radiation therapy (MRgRT) utilization is rapidly expanding worldwide, driven by advanced capabilities including continuous intrafraction visualization, automatic triggered beam delivery, and on-table adaptive replanning. Our objective was to describe patterns of 0.35T-MRgRT utilization in the United States (US) among early adopters of this novel technology.Materials/MethodsAnonymized administrative data from all US 0.35T-MRgRT treatment systems were extracted for patients completing treatment from 2014-2020. Detailed treatment information was available for all 0.35T-MR Linac system and some cobalt system patients. Most cobalt patients were included in total only.Results17 systems at 16 centers treated 5,733 patients, delivering 40,171 fractions (fractions unavailable for 1,225 cobalt patients), of which 6,244 (15.5%) were adapted. Thirteen centers (81.3%) had treated for > = 1 year, of which 9 treated > 100 patients/year and 6 treated > 150 patients/year. Ultra-hypofractionation (1-5 fractions) was delivered for 72.9% of all patients. The proportion of fractions adapted in patients receiving ultra-hypofractionation was 28.6%, with an average of 3.2 adapted fractions per course. The most commonly treated tumor types were pancreas (20.7%), liver (16.5%), prostate (12.5%), breast (11.5%), and lung (9.4%), respectively, with significantly increased number of fractions delivered from 2018-2020 compared to 2014-2017 for each (pancreas: 5,161 vs. 1,155; liver: 3,597 vs. 921; prostate: 5,795 vs. 1,398; breast: 2,221 vs. 1,876; lung: 2,589 vs. 660). The compound annual growth rate (CAGR) in the number of patients was 59.5%, growing from 111 in 2014 to 1,830 in 2020. Ultra-hypofractionation increased from 31.8% of all treated MR-Linac patients in 2014 to 87.0% in 2020 (n = 1,576/1,811). The proportion of adapted fractions in all patients and ultra-hypofractionation patients increased from 0% in the first two years to 24.3% (n = 3,071/12,639) and 33.8% (n = 2,677/7,911) respectively, by the end of 2020. No patient had adaptive treatment in 2014 although adaptive replanning steadily increased over time. For example, in 2020 vs. 2018 the proportion of adaptive fractions was highest for pancreas (60.6% vs. 50.8%), liver (17.8% vs. 9.9%), and lung (17.8% vs. 1.8%) cancers.ConclusionThis is the first comprehensive study reporting patterns of utilization among early adopters of a 0.35T-MRgRT system in the US. Intrafraction MR guidance, advanced motion management, and increasing adoption of adaptive RT has accelerated a transition to ultra-hypofractionation regimens. MRgRT has been predominantly used to treat abdominal and pelvic tumors, and increasingly with adaptive replanning, which is a radical departure from legacy radiotherapy practices. Magnetic resonance imaging-guided radiation therapy (MRgRT) utilization is rapidly expanding worldwide, driven by advanced capabilities including continuous intrafraction visualization, automatic triggered beam delivery, and on-table adaptive replanning. Our objective was to describe patterns of 0.35T-MRgRT utilization in the United States (US) among early adopters of this novel technology. Anonymized administrative data from all US 0.35T-MRgRT treatment systems were extracted for patients completing treatment from 2014-2020. Detailed treatment information was available for all 0.35T-MR Linac system and some cobalt system patients. Most cobalt patients were included in total only. 17 systems at 16 centers treated 5,733 patients, delivering 40,171 fractions (fractions unavailable for 1,225 cobalt patients), of which 6,244 (15.5%) were adapted. Thirteen centers (81.3%) had treated for > = 1 year, of which 9 treated > 100 patients/year and 6 treated > 150 patients/year. Ultra-hypofractionation (1-5 fractions) was delivered for 72.9% of all patients. The proportion of fractions adapted in patients receiving ultra-hypofractionation was 28.6%, with an average of 3.2 adapted fractions per course. The most commonly treated tumor types were pancreas (20.7%), liver (16.5%), prostate (12.5%), breast (11.5%), and lung (9.4%), respectively, with significantly increased number of fractions delivered from 2018-2020 compared to 2014-2017 for each (pancreas: 5,161 vs. 1,155; liver: 3,597 vs. 921; prostate: 5,795 vs. 1,398; breast: 2,221 vs. 1,876; lung: 2,589 vs. 660). The compound annual growth rate (CAGR) in the number of patients was 59.5%, growing from 111 in 2014 to 1,830 in 2020. Ultra-hypofractionation increased from 31.8% of all treated MR-Linac patients in 2014 to 87.0% in 2020 (n = 1,576/1,811). The proportion of adapted fractions in all patients and ultra-hypofractionation patients increased from 0% in the first two years to 24.3% (n = 3,071/12,639) and 33.8% (n = 2,677/7,911) respectively, by the end of 2020. No patient had adaptive treatment in 2014 although adaptive replanning steadily increased over time. For example, in 2020 vs. 2018 the proportion of adaptive fractions was highest for pancreas (60.6% vs. 50.8%), liver (17.8% vs. 9.9%), and lung (17.8% vs. 1.8%) cancers. This is the first comprehensive study reporting patterns of utilization among early adopters of a 0.35T-MRgRT system in the US. Intrafraction MR guidance, advanced motion management, and increasing adoption of adaptive RT has accelerated a transition to ultra-hypofractionation regimens. MRgRT has been predominantly used to treat abdominal and pelvic tumors, and increasingly with adaptive replanning, which is a radical departure from legacy radiotherapy practices.

MR-Guided Radiotherapy (MRgRT) for Laryngeal Cancer With Real-Time Visualization of Intrafraction Larynx Motion

Although early larynx cancers require treatment of only the vocal cord(s), radiation for early larynx cancer historically consisted of opposed lateral portals that included the entire larynx. Treatment techniques have advanced to 3D conformal and intensity modulated radiotherapy (IMRT), but the treatment target has remained the entire larynx. One concern preventing volume reduction in these patients is periodic swallowing that occurs during treatment delivery due to normal patient physiology. Such intrafraction swallowing can displace the treatment target up to 2 cm and could lead to tumor underdosing. Treatment with real-time target tracking could greatly mitigate this concern. Herein, we describe our initial experience using MR-guided radiotherapy (MRgRT) to visualize and understand the impact of intrafraction larynx motion.Three patients with cT1-2 laryngeal cancer were treated using an MRgRT Linac. Treatment volume included the entire larynx to evaluate feasibility of setup, immobilization, patient tracking, and treatment planning. A commercial MR-compatible head-and-heck immobilization system was developed and utilized, consisting of an indexable baseplate with integrated MR receiver coils affixed to a head cradle, with an open-face thermoplastic mask and head-mold cushion. Treatment plans were inversely planned utilizing 5 anterior IMRT fields to eliminate entrance dose to posterior organs at risk (OARs). The tracking structure consisted of patients' intrinsic larynx muscles delineated by a head and neck radiation oncologist on a 35cm x 35cm x 0.70cm sagittal MR plane. Patients were instructed not to swallow during setup imaging and during treatment. Continuous real-time tracking was performed at 4 frames per second with automatic beam hold if > 5% of the area of the tracking structure exceeded the 3mm isotropic boundary limit.Images were taken during patient treatment, and movement of the intrinsic muscles of the larynx was apparent in all patients due to periodic deglutition. At the time of analysis, 63 fractions have been delivered. The average total in-room time for the three patients in the study was 27:22 minutes (range 18:00 - 45:00 minutes), while the average beam-on time was 8:44 minutes (range 4:00 - 30:00 minutes).MR real-time visualization of the patient's intrinsic laryngeal muscles during MRgRT provides a method of gating treatment during patient swallowing. Robust intrafraction target tracking appears to enable higher confidence in reducing the treatment volume for early larynx cancers such that improvements in preservation of voice quality and deglutition capabilities are possible without sacrificing local control. A clinical trial is planned to examine such volume reduction and its effect on patient quality of life and function.

Automatic (Headlight) Beam Controlling module for two-wheelers

Abstract: Automatic High Beam controller is a device made due to the rising number of accidents at night because of LED headlamps temporarily affecting the vision of the driver on the opposite lane. According to AAA, LED lights do a much better job of illuminating the roadway, particularly in the low-beam application versus a halogen reflector at 150 feet more during testing. But, still, that brings the max vehicle speed to about 52 miles an hour, which is still falling short of highway speeds. So, the users are suggested to drive with high beam on if there is no oncoming traffic within a reasonable distance and the roadway is improperly lit. But in practice most people drive with the high beam settings in places with or without traffic great from the user's standpoint. However, even on low beam, they have such a high intensity that on 2-lane roads, especially when the oncoming driver of a car or small pickup approaches the LED equipped truck at night, in rain, fog, or snow the oncoming driver is blinded at a level equal to or greater than if the LED equipped vehicle were using conventional halogen high beams. This device is made without distance or ambient lighting being deciding factors and entirely based on user’s discretion. The transmitter model is fitted with a button that sends a signal to the receiver model using nrf24L01 modules and AT Mega 8 microcontroller (programmed using Arduino UNO). The pressing of button causes the state of the button to be set to HIGH. This signals the receiving circuit to set the LED pin to LOW. Therefore, the High Beam is set to Low Beam for 5 seconds when the impulse is received. Due to the use of H4 C6 headlamps which are rated for 36W with a minimum power requirement of 12W an adapter was connected to convert 220V AC supply to 12V, 3A DC supply for the LED and the rest of the circuit.

Artificial Intelligence DENTOMO: Opportunities and Prospects for analysis of CBCT in Dentistry

Analysis of artificial intelligence DENTOMO application efficiency, its opportunities and prospects for Interpretation of Cone Beam CT in Dentistry and developing model for automatic analysis cone beam computed tomography in Dentistry. The presented model is based on two convolutional neural networks, includes a database and knowledge base, harmonized with SNOMED Clinical Terms is a systematically organized computer processable collection of medical terms providing codes, terms, synonyms and definitions used in clinical documentation and reporting. The accuracy of AI model was assessed by calculating the ratio of false identifications to the true ones in each case. The model of artificial intelligence DENTOMO, which allows automated deciphering the CT in maxillofacial area, was developed and implemented in practical dentistry. The developed model automatically decodes cone beam CT images, identifies, and classifies the anatomical structures of the human dental system, and reveals the pathological processes and their dynamics in dentistry system. The developed model rather accurately identified the natural teeth in the frontal group as well in the group of premolars and molars. The recognition accuracy surpassed 90%. It should be noted that the developed model includes the possibility of “training”, which can improve the quality of evaluation of diagnostic features and related parameters. Moreover, it can add the current diagnostic potencies with novel features. Testing of DENTOMO model demonstrated a reasonable effectiveness in deciphering the CT of dental system. The developed technology allows computerizing and objectifying interpretation of CT of the dental system.

Voice Coil Actuator를 이용한 고속조준기의 구조설계 및 신뢰성 검증 연구

Because laser weapons are relatively easy to use and can exert powerful energy with high efficiency versus cost, the laser weapons are being developed competitively in the defense industry. A fast steering mirror is the key component for precision tracking and automatic beam alignment, which are the main performances of laser weapons. The purpose of this study is to verify the structural design and driving reliability for implementing the target performance of a fast steering mirror using voice coil actuators. For the performance evaluation of a fast steering mirror, the driving range for the available thrust considering of the electromagnetic force and also the dynamic characteristics within the driving bandwidth were investigated through electromagnetic and structural analysis. In addition, the structural robustness was verified by securing a sufficient safety factor based on the analysis of the fatigue life for the area where the stress was concentrated.

Pre‐training Dataset Generation Using Visual Explanation for Classifying Beam of Vehicle Headlights from Nighttime Camera Image

For Automatic High Beam (AHB), the authors are working on a study to classify beam of car headlights as ‘High’ and ‘Low’ by realizing the presence of vehicle on road from nighttime in‐vehicle camera image using deep learning. In general, weights of deep learning model are pre‐trained on a large dataset which are then used as initial weights for other tasks such as image recognition. However, it has been reported that even if the pre‐trained weights are used as the initial weights, it is not a factor of accuracy improvement when domain differs. It is important to pre‐train a model on a dataset that is suitable for target domain. Therefore, we propose a method to generate a pre‐training dataset that can be easily created by using visual explanation which represents where a deep learning model is looking at when performs a task. Then, we applied the proposed pre‐training dataset on the headlight beam classification in the nighttime in‐vehicle camera image and verified the effectiveness of our method. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Internet of Maritime Things Platform for Remote Marine Water Quality Monitoring

In this article, we show the development and implementation of the Internet of Maritime Things (IoMT) platform that supports long-range and high-rate communication for remote and online marine water quality monitoring. We first develop the IoMT device and gateway that interwork with international standard Internet-of-Things (IoT) software platforms for universal utilization in the field of marine monitoring. The proposed IoMT device and gateway play a role similar to the IoT device and gateway on land, but it is optimized for marine use with consideration of the practical characteristics of using sensors in the ocean. Furthermore, to realize long-range and high-rate communication between marine sensors and a control center (CC) on land, an automatic beam adjustment system for directional antennas is developed. This enables the use of directional antennas, which can support long-range and high-rate communication by automatically adjusting the beam angle between the antennas while exchanging their control information, despite the antennas being shifted by undulation from the sea. Finally, we conduct real sea experiments to identify the performances of the proposed IoMT platform in various environments. The results show that the proposed IoMT platform can collect data from marine sensors as well as high definition camera video from distances of 25 and 40 km to the CC on land under one-hop and two-hop transmissions, respectively. These results indicate that the proposed IoMT platform provides at least twofold performance improvement in terms of communication coverage under a similar data rate condition, compared with existing commercial wireless networks (e.g., LTE in the ocean) not utilizing satellite communications.

Reduction of heart and lung normal tissue complication probability using automatic beam angle optimization and more generic optimization objectives for breast radiotherapy.

During breast cancer radiotherapy, sparing of healthy tissue is desired. The effect of automatic beam angle optimization and generic dose fall-off objectives on dose and normal tissue complication probabilities was studied. In all patients, dose to lungs and heart showed a mean reduction of 0.4 Gy (range 0.1–1.3 Gy) and 0.2 Gy (range −0.2–0.7 Gy), respectively. These lower doses led to a statistically significant lower cumulative cardiac and lung cancer mortality risk. For smoking patients 40–45 years of age who continue to smoke, it would lead to a reduction from 3.2% ± 0.7% to 2.7% ± 0.6% (p < 0.001).

An Active Irradiation System with Automatic Beam Positioning and Focusing for a Medical Cyclotron

A novel active focusing system was developed for enhancing the irradiation performance of the 18 MeV medical cyclotron in operation at the Bern University Hospital in view of the production of non-conventional medical radioisotopes using solid targets. In several cases, such as the production of 43Sc and 44Sc, the beam has to be kept stable within a very small target of about 5 mm diameter. For this purpose, we conceived and realized an apparatus based on a compact focusing and steering magnet system followed by a two-dimensional beam monitoring detector and a specific feedback software that drives the magnet to optimize the beam for a given irradiation set-up. We report on the design, realization and validation beam tests performed using the research beam transfer line of the Bern cyclotron. We demonstrated that the beam spot can be kept on target thanks to the fact that the system automatically reacts to perturbations. Compactness is one of the key features of this system, allowing its use in accelerator facilities with limited space, such as medical cyclotrons for radioisotope production.

Design of ECU for Automatic Headlight Beam Control during City Driving

Automating the task of high beam switching will significantly reduce glare from oncoming vehicles and thus improving night time driving safety. To avoid temporary blindness and glare from oncoming vehicles, automatic high beam controller is developed by using an RF transmitter and receiver to control the high beam of the vehicle to low beam automatically while entering cities. This can be achieved by fixing RF transmitter at starting points of cities. Once a vehicle enters the city, the light beam control ECU in the vehicles receives signal from RF transmitter and the light beam of headlight of the vehicle is automatically switched to a low beam. Once the vehicle leaves the city by crossing RF transmitter the user input is enabled by ECU and the driver can change the beam either high or low manually according to his need. The circuit has been designed and simulated in the Proteus software and accurate switching of the high beam is achieved. This proposed system shows better performance, which will result in safe and glare-free driving at night times.