The Experts below are selected from a list of 55368 Experts worldwide ranked by ideXlab platform
Youngwoo Kwon - One of the best experts on this subject based on the ideXlab platform.
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a v band switched Beam forming antenna module using absorptive switch Integrated with 4 times 4 butler matrix in 0 13 mu hbox m cmos
IEEE Transactions on Microwave Theory and Techniques, 2010Co-Authors: Wooyeol Choi, K W Park, Youngwoo KwonAbstract:A Beam-forming antenna module is demonstrated using an Integrated CMOS Beam-former chip and a simple two-metal layer printed circuit board at V-band. The Beam-former circuit integrates an absorptive single-pole four-throw switch together with a 4 × 4 Butler matrix using a 0.13-μm CMOS process. The entire insertion loss of the Integrated Beam former Integrated circuit (IC) is around 7.5 dB at 60 GHz, among which 3 dB is attributed to the Butler matrix. The overall phase error is within ±12%. The antenna module employs backside radiation structure using series-fed patch antenna arrays to suppress parasitic radiation. The measured radiation pattern shows good agreement with the simulation. To the best of our knowledge, this is the first demonstration of the Beam-forming antenna module using a single-chip CMOS switched Beam-former IC at V-band.
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a v band switched Beam forming network using absorptive sp4t switch Integrated with 4 4 butler matrix in 0 13 µm cmos
International Microwave Symposium, 2010Co-Authors: K W Park, Wooyeol Choi, Youngwoo KwonAbstract:An Integrated switched Beam forming network is demonstrated at V-band by integrating an absorptive single-pole four-throw (SP4T) switch together with a 4×4 Butler matrix using 0.13 µm CMOS process. The fabricated absorptive SP4T switch shows a measured insertion loss of 4.5 dB at 60 GHz and isolation higher than 31 dB from 57 to 63 GHz. The return losses of the deactivated output ports also maintain better than 14 dB due to the absorptive configuration. The entire insertion loss of the Integrated Beam former IC was around 7.5 dB at 60 GHz, among which 3 dB is attributed to Butler matrix. The overall phase error was within ±12%. The calculated array factor from the measured S-parameters shows that the Beam-forming network generates four Beams at ±14°, ±54°. To the best of our knowledge, this is the first demonstration of CMOS switched Beam-forming network integrating an absorptive SP4T switch and Butler matrix at V-band.
E Romeijn - One of the best experts on this subject based on the ideXlab platform.
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su e t 608 Integrated Beam orientation and fluence map optimization in radiation therapy treatment planning
Medical Physics, 2012Co-Authors: Dan Ruan, T Long, P Dong, K Sheng, E RomeijnAbstract:Purpose: To efficiently select high‐quality coplanar or non‐coplanar Beam orientations for IMRTtreatments while formally and explicitly incorporating the effect of the selected Beam orientations on the quality of the dose distribution obtained by the treatment plan optimization model. Methods: Beam orientation models consider a discrete set of potential coplanar and/or non‐coplanar Beam locations around the patient. A new greedy algorithm is proposed to solve a model that integrates Beam orientation optimization (BOO) and fluence map optimization (FMO). The algorithm iteratively adds Beams to a FMO model. In each iteration, an attractiveness measure is associated with each remaining candidate Beam orientation. This attractiveness measure is based explicitly on an optimal dose distribution that allows only the currently selected set of Beams to be used. Several alternate attractiveness measures are considered which use either first‐order information or both first and second‐order information. Performance of the algorithm was assessed on a clinical lungcancer case. Results: The developed Beam selection algorithm was applied to a lungcancer case using either coplanar Beams or both coplanar and non‐coplanar Beams. In the coplanar case, Beam orientations were found that produce a superior dose distribution to that using an equal number of equi‐spaced Beams. In the non‐coplanar case it was found that fewer Beams were needed to produce a dose distribution of comparable quality to that found in the coplanar case. Conclusions: The developed solution approach showcases the potential benefits of integrating different steps in the treatment plan optimization process. By integrating the BOO and FMO models, treatment plan quality was explicitly incorporated into the Beam selection process. BOO can be automated and implemented efficiently, which eliminates the guesswork involved in manually adjusting Beam orientations in IMRTtreatment planning.
Dan Ruan - One of the best experts on this subject based on the ideXlab platform.
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Integrated Beam orientation and scanning spot optimization in intensity modulated proton therapy for brain and unilateral head and neck tumors
Medical Physics, 2018Co-Authors: Daniel T Oconnor, Dan Nguyen, Dan Ruan, Lei Dong, Ke ShengAbstract:PURPOSE Intensity-Modulated Proton Therapy (IMPT) is the state-of-the-art method of delivering proton radiotherapy. Previous research has been mainly focused on optimization of scanning spots with manually selected Beam angles. Due to the computational complexity, the potential benefit of simultaneously optimizing Beam orientations and spot pattern could not be realized. In this study, we developed a novel Integrated Beam orientation optimization (BOO) and scanning-spot optimization algorithm for intensity-modulated proton therapy (IMPT). METHODS A brain chordoma and three unilateral head-and-neck patients with a maximal target size of 112.49 cm3 were included in this study. A total number of 1162 noncoplanar candidate Beams evenly distributed across 4π steradians were included in the optimization. For each candidate Beam, the pencil-Beam doses of all scanning spots covering the PTV and a margin were calculated. The Beam angle selection and spot intensity optimization problem was formulated to include three terms: a dose fidelity term to penalize the deviation of PTV and OAR doses from ideal dose distribution; an L1-norm sparsity term to reduce the number of active spots and improve delivery efficiency; a group sparsity term to control the number of active Beams between 2 and 4. For the group sparsity term, convex L2,1-norm and nonconvex L2,1/2-norm were tested. For the dose fidelity term, both quadratic function and linearized equivalent uniform dose (LEUD) cost function were implemented. The optimization problem was solved using the Fast Iterative Shrinkage-Thresholding Algorithm (FISTA). The IMPT BOO method was tested on three head-and-neck patients and one skull base chordoma patient. The results were compared with IMPT plans created using column generation selected Beams or manually selected Beams. RESULTS The L2,1-norm plan selected spatially aggregated Beams, indicating potential degeneracy using this norm. L2,1/2-norm was able to select spatially separated Beams and achieve smaller deviation from the ideal dose. In the L2,1/2-norm plans, the [mean dose, maximum dose] of OAR were reduced by an average of [2.38%, 4.24%] and[2.32%, 3.76%] of the prescription dose for the quadratic and LEUD cost function, respectively, compared with the IMPT plan using manual Beam selection while maintaining the same PTV coverage. The L2,1/2 group sparsity plans were dosimetrically superior to the column generation plans as well. Besides Beam orientation selection, spot sparsification was observed. Generally, with the quadratic cost function, 30%~60% spots in the selected Beams remained active. With the LEUD cost function, the percentages of active spots were in the range of 35%~85%.The BOO-IMPT run time was approximately 20 min. CONCLUSION This work shows the first IMPT approach integrating noncoplanar BOO and scanning-spot optimization in a single mathematical framework. This method is computationally efficient, dosimetrically superior and produces delivery-friendly IMPT plans.
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su e t 608 Integrated Beam orientation and fluence map optimization in radiation therapy treatment planning
Medical Physics, 2012Co-Authors: Dan Ruan, T Long, P Dong, K Sheng, E RomeijnAbstract:Purpose: To efficiently select high‐quality coplanar or non‐coplanar Beam orientations for IMRTtreatments while formally and explicitly incorporating the effect of the selected Beam orientations on the quality of the dose distribution obtained by the treatment plan optimization model. Methods: Beam orientation models consider a discrete set of potential coplanar and/or non‐coplanar Beam locations around the patient. A new greedy algorithm is proposed to solve a model that integrates Beam orientation optimization (BOO) and fluence map optimization (FMO). The algorithm iteratively adds Beams to a FMO model. In each iteration, an attractiveness measure is associated with each remaining candidate Beam orientation. This attractiveness measure is based explicitly on an optimal dose distribution that allows only the currently selected set of Beams to be used. Several alternate attractiveness measures are considered which use either first‐order information or both first and second‐order information. Performance of the algorithm was assessed on a clinical lungcancer case. Results: The developed Beam selection algorithm was applied to a lungcancer case using either coplanar Beams or both coplanar and non‐coplanar Beams. In the coplanar case, Beam orientations were found that produce a superior dose distribution to that using an equal number of equi‐spaced Beams. In the non‐coplanar case it was found that fewer Beams were needed to produce a dose distribution of comparable quality to that found in the coplanar case. Conclusions: The developed solution approach showcases the potential benefits of integrating different steps in the treatment plan optimization process. By integrating the BOO and FMO models, treatment plan quality was explicitly incorporated into the Beam selection process. BOO can be automated and implemented efficiently, which eliminates the guesswork involved in manually adjusting Beam orientations in IMRTtreatment planning.
Ke Sheng - One of the best experts on this subject based on the ideXlab platform.
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Integrated Beam orientation and scanning spot optimization in intensity modulated proton therapy for brain and unilateral head and neck tumors
Medical Physics, 2018Co-Authors: Daniel T Oconnor, Dan Nguyen, Dan Ruan, Lei Dong, Ke ShengAbstract:PURPOSE Intensity-Modulated Proton Therapy (IMPT) is the state-of-the-art method of delivering proton radiotherapy. Previous research has been mainly focused on optimization of scanning spots with manually selected Beam angles. Due to the computational complexity, the potential benefit of simultaneously optimizing Beam orientations and spot pattern could not be realized. In this study, we developed a novel Integrated Beam orientation optimization (BOO) and scanning-spot optimization algorithm for intensity-modulated proton therapy (IMPT). METHODS A brain chordoma and three unilateral head-and-neck patients with a maximal target size of 112.49 cm3 were included in this study. A total number of 1162 noncoplanar candidate Beams evenly distributed across 4π steradians were included in the optimization. For each candidate Beam, the pencil-Beam doses of all scanning spots covering the PTV and a margin were calculated. The Beam angle selection and spot intensity optimization problem was formulated to include three terms: a dose fidelity term to penalize the deviation of PTV and OAR doses from ideal dose distribution; an L1-norm sparsity term to reduce the number of active spots and improve delivery efficiency; a group sparsity term to control the number of active Beams between 2 and 4. For the group sparsity term, convex L2,1-norm and nonconvex L2,1/2-norm were tested. For the dose fidelity term, both quadratic function and linearized equivalent uniform dose (LEUD) cost function were implemented. The optimization problem was solved using the Fast Iterative Shrinkage-Thresholding Algorithm (FISTA). The IMPT BOO method was tested on three head-and-neck patients and one skull base chordoma patient. The results were compared with IMPT plans created using column generation selected Beams or manually selected Beams. RESULTS The L2,1-norm plan selected spatially aggregated Beams, indicating potential degeneracy using this norm. L2,1/2-norm was able to select spatially separated Beams and achieve smaller deviation from the ideal dose. In the L2,1/2-norm plans, the [mean dose, maximum dose] of OAR were reduced by an average of [2.38%, 4.24%] and[2.32%, 3.76%] of the prescription dose for the quadratic and LEUD cost function, respectively, compared with the IMPT plan using manual Beam selection while maintaining the same PTV coverage. The L2,1/2 group sparsity plans were dosimetrically superior to the column generation plans as well. Besides Beam orientation selection, spot sparsification was observed. Generally, with the quadratic cost function, 30%~60% spots in the selected Beams remained active. With the LEUD cost function, the percentages of active spots were in the range of 35%~85%.The BOO-IMPT run time was approximately 20 min. CONCLUSION This work shows the first IMPT approach integrating noncoplanar BOO and scanning-spot optimization in a single mathematical framework. This method is computationally efficient, dosimetrically superior and produces delivery-friendly IMPT plans.
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th ab brb 00 research opportunities with digital linear accelerators
Medical Physics, 2016Co-Authors: Ke ShengAbstract:Current state-of-the art digital C-arm medical linear accelerators are capable of delivering radiation treatments with high level of automation, which affords coordinated motions of gantry, couch, and multileaf collimator (MLC) with dose rate modulations. The new machine capacity has shown the potential to bring substantially improved radiation dosimetry and/or delivery efficiency to many challenging diseases. Combining an Integrated Beam orientation optimization algorithm with automated machine navigation, markedly improved dose conformity has been achieved using 4ρ therapy. Trajectory modulated radiation therapy (TMAT) can be used to deliver highly conformal dose to partial breast or to carve complex dose distribution for therapy involving extended volumes such as total marrow and total lymph node treatment. Dynamic electron arc radiotherapy (DEAR) not only overcomes the deficiencies of conventional electron therapy in dose conformity and homogeneity but also achieves so without patient-specific shields. The combination of MLC and couch tracking provides improved motion management of thoracic and abdominal tumors. A substantial body of work has been done in these technological advances for clinical translation. The proposed symposium will provide a timely review of these exciting opportunities. Learning Objectives: 1.Recognize the potential of using digitally controlled linacs for clinically significant improvements in delivered dose distributions for various treatment sites. 2.Identify existing approaches to treatment planning, optimization and delivery for treatment techniques utilizing the advanced functions of digital linacs and venues for further development and improvement. 3.Understand methods for testing and validating delivery system performance. 4.Identify tools available on current delivery systems for implementation and control for such treatments. 5.Obtain the update in clinical applications, trials and regulatory approval. K. Sheng, NIH U19AI067769, NIH R43CA183390, NIH R01CA188300, Varian Medical Systems V. Yu, Varian Medical Systems, AAPM Summer Undergraduate Fellowship, NSF graduate fellowship S. Nill, Elekta AB. Cancer Research UK under Programme C33589/A19727, NIHR Biomedical Research Centre at The Royal Marsden and The Institute of Cancer Research.
Wooyeol Choi - One of the best experts on this subject based on the ideXlab platform.
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a v band switched Beam forming antenna module using absorptive switch Integrated with 4 times 4 butler matrix in 0 13 mu hbox m cmos
IEEE Transactions on Microwave Theory and Techniques, 2010Co-Authors: Wooyeol Choi, K W Park, Youngwoo KwonAbstract:A Beam-forming antenna module is demonstrated using an Integrated CMOS Beam-former chip and a simple two-metal layer printed circuit board at V-band. The Beam-former circuit integrates an absorptive single-pole four-throw switch together with a 4 × 4 Butler matrix using a 0.13-μm CMOS process. The entire insertion loss of the Integrated Beam former Integrated circuit (IC) is around 7.5 dB at 60 GHz, among which 3 dB is attributed to the Butler matrix. The overall phase error is within ±12%. The antenna module employs backside radiation structure using series-fed patch antenna arrays to suppress parasitic radiation. The measured radiation pattern shows good agreement with the simulation. To the best of our knowledge, this is the first demonstration of the Beam-forming antenna module using a single-chip CMOS switched Beam-former IC at V-band.
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a v band switched Beam forming network using absorptive sp4t switch Integrated with 4 4 butler matrix in 0 13 µm cmos
International Microwave Symposium, 2010Co-Authors: K W Park, Wooyeol Choi, Youngwoo KwonAbstract:An Integrated switched Beam forming network is demonstrated at V-band by integrating an absorptive single-pole four-throw (SP4T) switch together with a 4×4 Butler matrix using 0.13 µm CMOS process. The fabricated absorptive SP4T switch shows a measured insertion loss of 4.5 dB at 60 GHz and isolation higher than 31 dB from 57 to 63 GHz. The return losses of the deactivated output ports also maintain better than 14 dB due to the absorptive configuration. The entire insertion loss of the Integrated Beam former IC was around 7.5 dB at 60 GHz, among which 3 dB is attributed to Butler matrix. The overall phase error was within ±12%. The calculated array factor from the measured S-parameters shows that the Beam-forming network generates four Beams at ±14°, ±54°. To the best of our knowledge, this is the first demonstration of CMOS switched Beam-forming network integrating an absorptive SP4T switch and Butler matrix at V-band.