Khaldon Lweesy | Jordan University of Science and Technology (original) (raw)
Papers by Khaldon Lweesy
Materials Research Innovations, Jun 1, 2004
Abstract This paper describes the design, construction, and evaluation of a 1.75 dimensional (1.7... more Abstract This paper describes the design, construction, and evaluation of a 1.75 dimensional (1.75-D) tapered ultrasound phased array to be used in the treatment of benign prostatic hyperplasia and prostate cancer. The array was designed to be able to focus and steer in a three dimensional volume with a maximum steering angle of ±13.5° in the transverse direction and a maximum depth of penetration of 11 cm, which allows the treatment of large prostates. A piezoelectric ceramic (PZT-8) at a frequency of 1.2 MHz was used as the material of the transducer since it can handle the high power needed for tissue ablation and two matching layers were used for maximum acoustic power transmission to tissue. To verify the capability of the transducer for focusing and steering, exposimetry was performed and the results correlated well with the calculated field.
journal of engineering science and technology, Apr 1, 2021
International Journal of Hyperthermia, 2004
This paper describes the design, construction and evaluation of a two-dimensional ultrasound phas... more This paper describes the design, construction and evaluation of a two-dimensional ultrasound phased array to be used in the treatment of benign prostatic hyperplasia. With two-dimensional phased arrays, the focal point position can be controlled by changing the electrical power and phase to the individual elements for focusing and electronically steering in a three-dimensional volume. The array was designed with a steering angle of +/-14 degrees in both transverse and longitudinal directions. A piezoelectric ceramic (PZT-8) was used as the material of the transducer, since it can handle the high power needed for tissue ablation and a matching layer was used for maximum acoustic power transmission to tissue. Analysis of the transducer ceramic and cable impedance has been designed for high power transfer with minimal capacitance and diameter. For this initial prototype, the final construction used magnet compatible housing and cabling for future application in a clinical magnetic resonance imaging system for temperature mapping of the focused ultrasound. To verify the capability of the transducer for focusing and steering, exposimetry was performed and the results correlated well with the calculated field. Ex vivo experiments were performed and indicated the capability of the transducer to ablate tissue using short sonications. For sonications with exposure time of 10, 15 and 20 s, the lesion size was roughly 1.8, 3.0 and 4.3 mm in diameter, respectively, which indicates the feasibility of this device.
2022 International Workshop on Impedance Spectroscopy (IWIS)
2021 18th International Multi-Conference on Systems, Signals & Devices (SSD), 2021
Hand gesture recognition presents one of the most important aspects for human machine interface (... more Hand gesture recognition presents one of the most important aspects for human machine interface (HMI) development, and it has a wide spectrum of applications including sign language recognition for deaf and dumb people. Herein, force myography signals (FMG) are extracted using eight nanocomposite CNT/PDMS pressure sensors simultaneously. Data are collected from eight healthy volunteers for American sign language digits 0–9. Two sets of features are extracted, the first one is composed of mean, standard deviation and rms values for the raw FMG data for all 8 sensors individually. The second set is composed of the 2-norm of the raw FMG signal and three proportional features, where the FMG signals are studied with respect to the reference rest signal. Classification is performed using each of the seven individual features as well as the combination of features in each set. The combination of features in the second set gives better testing accuracy of 95%, 91.9% for $\mathrm{k}=2,\ \mat...
2021 18th International Multi-Conference on Systems, Signals & Devices (SSD), 2021
Hand gesture recognition presents one of the most important aspects for human machine interface (... more Hand gesture recognition presents one of the most important aspects for human machine interface (HMI) development, and it has a wide spectrum of applications including sign language recognition for deaf and dumb people. Herein, force myography signals (FMG) are extracted using eight nanocomposite CNT/PDMS pressure sensors simultaneously. Data are collected from eight healthy volunteers for American sign language digits 0–9. Two sets of features are extracted, the first one is composed of mean, standard deviation and rms values for the raw FMG data for all 8 sensors individually. The second set is composed of the 2-norm of the raw FMG signal and three proportional features, where the FMG signals are studied with respect to the reference rest signal. Classification is performed using each of the seven individual features as well as the combination of features in each set. The combination of features in the second set gives better testing accuracy of 95%, 91.9% for $\mathrm{k}=2,\ \mat...
Abstract—This paper describes a new method for extracting the fetal heart rate (fHR) and the feta... more Abstract—This paper describes a new method for extracting the fetal heart rate (fHR) and the fetal heart rate variability (fHRV) signal non-invasively using abdominal maternal electrocardiogram (mECG) recordings. The extraction is based on the fundamental frequency (Fourier’s) theorem. The fundamental frequency of the mother’s electrocardiogram signal (fo-m) is calculated directly from the abdominal signal. The heart rate of the fetus is usually higher than that of the mother; as a result, the fundamental frequency of the fetal’s electrocardiogram signal (fo-f) is higher than that of the mother’s (fo-f> fo-m). Notch filters to suppress mother’s higher harmonics were designed; then a bandpass filter to target fo-f and reject fo-m is implemented. Although the bandpass filter will pass some other frequencies (harmonics), we have shown in this study that those harmonics are actually carried on fo-f, and thus have no impact on the evaluation of the beat-to-beat changes (RR intervals)....
2021 18th International Multi-Conference on Systems, Signals & Devices (SSD), 2021
In recent years, force myography (FMG) is considered a non-invasive method used for the recogniti... more In recent years, force myography (FMG) is considered a non-invasive method used for the recognition of different gestures such as the American sign language (ASL) by measuring presser changes due to different variations in muscle volume while performing different signs. In this work, only six FSR commercial sensors were inserted to the inner side of a bracelet to be in direct contact with the skin was used to collect the raw FMG signal from 10 healthy subjects with 10 trails. In this paper, an extreme learning machine (ELM) with cross-validation ($\text{Kfold}=5$) was applied to test the accuracy of using raw FMG signal in comparison with only six time domain extracted features. The results show that the accuracy based on extracting six features was equal to 91.11%, which outperforms the raw FMG signal for gesture recognition where it reached only a testing accuracy of 85.56%.
World Academy of Science, Engineering and Technology, International Journal of Medical, Health, Biomedical, Bioengineering and Pharmaceutical Engineering, 2009
Sleep stage scoring is the process of classifying the stage of the sleep in which the subject is ... more Sleep stage scoring is the process of classifying the stage of the sleep in which the subject is in. Sleep is classified into two states based on the constellation of physiological parameters. The two states are the non-rapid eye movement (NREM) and the rapid eye movement (REM). The NREM sleep is also classified into four stages (1-4). These states and the state wakefulness are distinguished from each other based on the brain activity. In this work, a classification method for automated sleep stage scoring based on a single EEG recording using wavelet packet decomposition was implemented. Thirty two ploysomnographic recording from the MIT-BIH database were used for training and validation of the proposed method. A single EEG recording was extracted and smoothed using Savitzky-Golay filter. Wavelet packets decomposition up to the fourth level based on 20 order Daubechies filter was used to extract features from the EEG signal. A features vector of 54 features was formed. It was reduc...
This paper describes a new method for extracting the fetal heart rate (fHR) and the fetal heart r... more This paper describes a new method for extracting the fetal heart rate (fHR) and the fetal heart rate variability (fHRV) signal non-invasively using abdominal maternal electrocardiogram (mECG) recordings. The extraction is based on the fundamental frequency (Fourier’s) theorem. The fundamental frequency of the mother’s electrocardiogram signal (fo-m) is calculated directly from the abdominal signal. The heart rate of the fetus is usually higher than that of the mother; as a result, the fundamental frequency of the fetal’s electrocardiogram signal (fo-f) is higher than that of the mother’s (fo-f > fo-m). Notch filters to suppress mother’s higher harmonics were designed; then a bandpass filter to target fo-f and reject fo-m is implemented. Although the bandpass filter will pass some other frequencies (harmonics), we have shown in this study that those harmonics are actually carried on fo-f, and thus have no impact on the evaluation of the beat-to-beat changes (RR intervals). The osc...
This paper describes the design, construction, and evaluation of a three-dimensional (3D) ultraso... more This paper describes the design, construction, and evaluation of a three-dimensional (3D) ultrasound system to he used for tumor treatment using high-intensity focused ultrasound (HIFU). The system consists of Iwo parts: an ultrasonic therapy part and a treatment planning part. The ultrasonic therapy part consists of an ultrasound bowl-shaped transducer made from lead zirconate titanate (PZT) and with a resonance frequency of 0.5 MHz. Electrical LC matching circuit built for maximum electrical power delivery to the transducer, a function generator, and a power amplifier. The ultrasonic therapy pal is designed for generating a focus with high acoustical powers. The treatment planning pat consists of three stepper motors (responsible for moving the setup in the x-y-and 7-directions), three high-voltage high-current Darlington arrays (to supply the stepper motors with the required voltages and currents), and C# software to perform the treatment planning. To assess the movement of the t...
Sensors
Non-contact physiological measurements have been under investigation for many years, and among th... more Non-contact physiological measurements have been under investigation for many years, and among these measurements is non-contact spirometry, which could provide acute and chronic pulmonary disease monitoring and diagnosis. This work presents a feasibility study for non-contact spirometry measurements using a mobile thermal imaging system. Thermal images were acquired from 19 subjects for measuring the respiration rate and the volume of inhaled and exhaled air. A mobile application was built to measure the respiration rate and export the respiration signal to a personal computer. The mobile application acquired thermal video images at a rate of nine frames/second and the OpenCV library was used for localization of the area of interest (nose and mouth). Artificial intelligence regressors were used to predict the inhalation and exhalation air volume. Several regressors were tested and four of them showed excellent performance: random forest, adaptive boosting, gradient boosting, and de...
International Journal of Hyperthermia
Objective: Importance of laser pulsing parameters and tissue's mechanical properties in the Er:YA... more Objective: Importance of laser pulsing parameters and tissue's mechanical properties in the Er:YAG laser skin-tissue ablation is not adequately understood. The goal here was to develop a computational model that incorporates skin tissue's mechanical properties to investigate the influence of Er:YAG laser pulsing parameters on tissue ablation and coagulation. Methods: Tissue's mechanical properties were incorporated by modeling ablation as a tissue water vaporization occurring under elevated pressures that depend on tissue's stress-strain relationships. Tissue deformation was assumed unidirectional; therefore, a one-dimensional model was utilized. Analytical solution and experimental results were used to verify and validate the model. Then, influence of pulse duration (10 ms-2 ms) and fluence (0-30 J cm À2) on coagulation depth and ablation efficiency was explored. Results: Verification and validation results suggested that the model is acceptably accurate. Minimal effect of pulse duration on coagulation depth was predicted at sub-ablative conditions. At those conditions, coagulation depth increased asymptotically to $90 mm with increasing pulse fluence. At ablative conditions, coagulation depth decreased asymptotically to 22-28 mm with increasing pulse irradiance. Ablation efficiency plateaued at high pulse fluences and long pulse durations. Mechanical properties were important as about 50% increase in coagulation depth and 25% decrease in ablation efficiency were predicted when considering the high strain-rate loading effect in comparison with quasi-static loading. Conclusions: Proper tuning of Er:YAG laser pulsing parameters can substantially improve its therapeutic outcomes. The effect of these parameters varies and depends on whether the laser-tissue conditions are ablative or sub-ablative.
2017 IEEE 13th International Colloquium on Signal Processing & its Applications (CSPA)
AIP Conference Proceedings
This paper presents engineering progress and the latest in-vitro and in-vivo results obtained wit... more This paper presents engineering progress and the latest in-vitro and in-vivo results obtained with a 4.0 MHz, 20 element, PZT annular transrectal HIFU array and several 4.0 MHz, 211 element, PZT and piezocomposite cylindrical transrectal HIFU arrays for the treatment of prostate cancer. The geometries of both arrays were designed and analyzed to steer the HIFU beams to the desired sites in the prostate volume using multi-channel electronic drivers, with the intent to increase treatment efficiency and reliability for the next generation of HIFU systems. The annular array is able to focus in depth from 25 mm to 50 mm, generate total acoustic powers in excess of 60W, and has been integrated into a modified Sonablate ® 500 HIFU system capable of controlling such an applicator through custom treatment planning and execution software. Both PZT-and piezocomposite cylindrical arrays were constructed and their characteristics were compared for the transrectal applications. These arrays have been installed into appropriate transducer housings, and have undergone characterization tests to determine their total acoustic power output, focusing range (in depth and laterally), focus quality, efficiency, and comparison tests to determine the material and technology of choice (PZT or piezocomposite) for intra-cavity HIFU applications. Array descriptions, characterization results, in-vitro and in-vivo results, and an overview of their intended use through the application software is shown.
Materials Research Innovations, 2006
IFMBE Proceedings, 2009
ABSTRACT This paper describes the design, construction, and evaluation of a three dimensional (3D... more ABSTRACT This paper describes the design, construction, and evaluation of a three dimensional (3D) ultrasound system to be used in the treatment of kidney tumors using high intensity focused ultrasound (HIFU). The system consists of a single element focused ultrasound transducer and a 3D positioning system. The single element ultrasound transducer (1 MHz) was bowl shaped with a geometric focus of 10 cm and was made from PZT4 material. The 3D positioning system was designed and built to move in polar coordinates. It has three stepper motors, some mechanical parts for support, and electronic circuits to control the movement of the motors and to control the on and off times of the transducer.
Journal of Medical Imaging and Health Informatics, 2011
Biomedical engineering online, Jan 17, 2005
Prostate cancer and benign prostatic hyperplasia are very common diseases in older American men, ... more Prostate cancer and benign prostatic hyperplasia are very common diseases in older American men, thus having a reliable treatment modality for both diseases is of great importance. The currently used treating options, mainly surgical ones, have numerous complications, which include the many side effects that accompany such procedures, besides the invasive nature of such techniques. Focused ultrasound is a relatively new treating modality that is showing promising results in treating prostate cancer and benign prostatic hyperplasia. Thus this technique is gaining more attention in the past decade as a non-invasive method to treat both diseases. In this paper, the design, construction and evaluation of a 1.75 dimensional ultrasound phased array to be used for treating prostate cancer and benign prostatic hyperplasia is presented. With this array, the position of the focus can be controlled by changing the electrical power and phase to the individual elements for electronically focusin...
Materials Research Innovations, Jun 1, 2004
Abstract This paper describes the design, construction, and evaluation of a 1.75 dimensional (1.7... more Abstract This paper describes the design, construction, and evaluation of a 1.75 dimensional (1.75-D) tapered ultrasound phased array to be used in the treatment of benign prostatic hyperplasia and prostate cancer. The array was designed to be able to focus and steer in a three dimensional volume with a maximum steering angle of ±13.5° in the transverse direction and a maximum depth of penetration of 11 cm, which allows the treatment of large prostates. A piezoelectric ceramic (PZT-8) at a frequency of 1.2 MHz was used as the material of the transducer since it can handle the high power needed for tissue ablation and two matching layers were used for maximum acoustic power transmission to tissue. To verify the capability of the transducer for focusing and steering, exposimetry was performed and the results correlated well with the calculated field.
journal of engineering science and technology, Apr 1, 2021
International Journal of Hyperthermia, 2004
This paper describes the design, construction and evaluation of a two-dimensional ultrasound phas... more This paper describes the design, construction and evaluation of a two-dimensional ultrasound phased array to be used in the treatment of benign prostatic hyperplasia. With two-dimensional phased arrays, the focal point position can be controlled by changing the electrical power and phase to the individual elements for focusing and electronically steering in a three-dimensional volume. The array was designed with a steering angle of +/-14 degrees in both transverse and longitudinal directions. A piezoelectric ceramic (PZT-8) was used as the material of the transducer, since it can handle the high power needed for tissue ablation and a matching layer was used for maximum acoustic power transmission to tissue. Analysis of the transducer ceramic and cable impedance has been designed for high power transfer with minimal capacitance and diameter. For this initial prototype, the final construction used magnet compatible housing and cabling for future application in a clinical magnetic resonance imaging system for temperature mapping of the focused ultrasound. To verify the capability of the transducer for focusing and steering, exposimetry was performed and the results correlated well with the calculated field. Ex vivo experiments were performed and indicated the capability of the transducer to ablate tissue using short sonications. For sonications with exposure time of 10, 15 and 20 s, the lesion size was roughly 1.8, 3.0 and 4.3 mm in diameter, respectively, which indicates the feasibility of this device.
2022 International Workshop on Impedance Spectroscopy (IWIS)
2021 18th International Multi-Conference on Systems, Signals & Devices (SSD), 2021
Hand gesture recognition presents one of the most important aspects for human machine interface (... more Hand gesture recognition presents one of the most important aspects for human machine interface (HMI) development, and it has a wide spectrum of applications including sign language recognition for deaf and dumb people. Herein, force myography signals (FMG) are extracted using eight nanocomposite CNT/PDMS pressure sensors simultaneously. Data are collected from eight healthy volunteers for American sign language digits 0–9. Two sets of features are extracted, the first one is composed of mean, standard deviation and rms values for the raw FMG data for all 8 sensors individually. The second set is composed of the 2-norm of the raw FMG signal and three proportional features, where the FMG signals are studied with respect to the reference rest signal. Classification is performed using each of the seven individual features as well as the combination of features in each set. The combination of features in the second set gives better testing accuracy of 95%, 91.9% for $\mathrm{k}=2,\ \mat...
2021 18th International Multi-Conference on Systems, Signals & Devices (SSD), 2021
Hand gesture recognition presents one of the most important aspects for human machine interface (... more Hand gesture recognition presents one of the most important aspects for human machine interface (HMI) development, and it has a wide spectrum of applications including sign language recognition for deaf and dumb people. Herein, force myography signals (FMG) are extracted using eight nanocomposite CNT/PDMS pressure sensors simultaneously. Data are collected from eight healthy volunteers for American sign language digits 0–9. Two sets of features are extracted, the first one is composed of mean, standard deviation and rms values for the raw FMG data for all 8 sensors individually. The second set is composed of the 2-norm of the raw FMG signal and three proportional features, where the FMG signals are studied with respect to the reference rest signal. Classification is performed using each of the seven individual features as well as the combination of features in each set. The combination of features in the second set gives better testing accuracy of 95%, 91.9% for $\mathrm{k}=2,\ \mat...
Abstract—This paper describes a new method for extracting the fetal heart rate (fHR) and the feta... more Abstract—This paper describes a new method for extracting the fetal heart rate (fHR) and the fetal heart rate variability (fHRV) signal non-invasively using abdominal maternal electrocardiogram (mECG) recordings. The extraction is based on the fundamental frequency (Fourier’s) theorem. The fundamental frequency of the mother’s electrocardiogram signal (fo-m) is calculated directly from the abdominal signal. The heart rate of the fetus is usually higher than that of the mother; as a result, the fundamental frequency of the fetal’s electrocardiogram signal (fo-f) is higher than that of the mother’s (fo-f> fo-m). Notch filters to suppress mother’s higher harmonics were designed; then a bandpass filter to target fo-f and reject fo-m is implemented. Although the bandpass filter will pass some other frequencies (harmonics), we have shown in this study that those harmonics are actually carried on fo-f, and thus have no impact on the evaluation of the beat-to-beat changes (RR intervals)....
2021 18th International Multi-Conference on Systems, Signals & Devices (SSD), 2021
In recent years, force myography (FMG) is considered a non-invasive method used for the recogniti... more In recent years, force myography (FMG) is considered a non-invasive method used for the recognition of different gestures such as the American sign language (ASL) by measuring presser changes due to different variations in muscle volume while performing different signs. In this work, only six FSR commercial sensors were inserted to the inner side of a bracelet to be in direct contact with the skin was used to collect the raw FMG signal from 10 healthy subjects with 10 trails. In this paper, an extreme learning machine (ELM) with cross-validation ($\text{Kfold}=5$) was applied to test the accuracy of using raw FMG signal in comparison with only six time domain extracted features. The results show that the accuracy based on extracting six features was equal to 91.11%, which outperforms the raw FMG signal for gesture recognition where it reached only a testing accuracy of 85.56%.
World Academy of Science, Engineering and Technology, International Journal of Medical, Health, Biomedical, Bioengineering and Pharmaceutical Engineering, 2009
Sleep stage scoring is the process of classifying the stage of the sleep in which the subject is ... more Sleep stage scoring is the process of classifying the stage of the sleep in which the subject is in. Sleep is classified into two states based on the constellation of physiological parameters. The two states are the non-rapid eye movement (NREM) and the rapid eye movement (REM). The NREM sleep is also classified into four stages (1-4). These states and the state wakefulness are distinguished from each other based on the brain activity. In this work, a classification method for automated sleep stage scoring based on a single EEG recording using wavelet packet decomposition was implemented. Thirty two ploysomnographic recording from the MIT-BIH database were used for training and validation of the proposed method. A single EEG recording was extracted and smoothed using Savitzky-Golay filter. Wavelet packets decomposition up to the fourth level based on 20 order Daubechies filter was used to extract features from the EEG signal. A features vector of 54 features was formed. It was reduc...
This paper describes a new method for extracting the fetal heart rate (fHR) and the fetal heart r... more This paper describes a new method for extracting the fetal heart rate (fHR) and the fetal heart rate variability (fHRV) signal non-invasively using abdominal maternal electrocardiogram (mECG) recordings. The extraction is based on the fundamental frequency (Fourier’s) theorem. The fundamental frequency of the mother’s electrocardiogram signal (fo-m) is calculated directly from the abdominal signal. The heart rate of the fetus is usually higher than that of the mother; as a result, the fundamental frequency of the fetal’s electrocardiogram signal (fo-f) is higher than that of the mother’s (fo-f > fo-m). Notch filters to suppress mother’s higher harmonics were designed; then a bandpass filter to target fo-f and reject fo-m is implemented. Although the bandpass filter will pass some other frequencies (harmonics), we have shown in this study that those harmonics are actually carried on fo-f, and thus have no impact on the evaluation of the beat-to-beat changes (RR intervals). The osc...
This paper describes the design, construction, and evaluation of a three-dimensional (3D) ultraso... more This paper describes the design, construction, and evaluation of a three-dimensional (3D) ultrasound system to he used for tumor treatment using high-intensity focused ultrasound (HIFU). The system consists of Iwo parts: an ultrasonic therapy part and a treatment planning part. The ultrasonic therapy part consists of an ultrasound bowl-shaped transducer made from lead zirconate titanate (PZT) and with a resonance frequency of 0.5 MHz. Electrical LC matching circuit built for maximum electrical power delivery to the transducer, a function generator, and a power amplifier. The ultrasonic therapy pal is designed for generating a focus with high acoustical powers. The treatment planning pat consists of three stepper motors (responsible for moving the setup in the x-y-and 7-directions), three high-voltage high-current Darlington arrays (to supply the stepper motors with the required voltages and currents), and C# software to perform the treatment planning. To assess the movement of the t...
Sensors
Non-contact physiological measurements have been under investigation for many years, and among th... more Non-contact physiological measurements have been under investigation for many years, and among these measurements is non-contact spirometry, which could provide acute and chronic pulmonary disease monitoring and diagnosis. This work presents a feasibility study for non-contact spirometry measurements using a mobile thermal imaging system. Thermal images were acquired from 19 subjects for measuring the respiration rate and the volume of inhaled and exhaled air. A mobile application was built to measure the respiration rate and export the respiration signal to a personal computer. The mobile application acquired thermal video images at a rate of nine frames/second and the OpenCV library was used for localization of the area of interest (nose and mouth). Artificial intelligence regressors were used to predict the inhalation and exhalation air volume. Several regressors were tested and four of them showed excellent performance: random forest, adaptive boosting, gradient boosting, and de...
International Journal of Hyperthermia
Objective: Importance of laser pulsing parameters and tissue's mechanical properties in the Er:YA... more Objective: Importance of laser pulsing parameters and tissue's mechanical properties in the Er:YAG laser skin-tissue ablation is not adequately understood. The goal here was to develop a computational model that incorporates skin tissue's mechanical properties to investigate the influence of Er:YAG laser pulsing parameters on tissue ablation and coagulation. Methods: Tissue's mechanical properties were incorporated by modeling ablation as a tissue water vaporization occurring under elevated pressures that depend on tissue's stress-strain relationships. Tissue deformation was assumed unidirectional; therefore, a one-dimensional model was utilized. Analytical solution and experimental results were used to verify and validate the model. Then, influence of pulse duration (10 ms-2 ms) and fluence (0-30 J cm À2) on coagulation depth and ablation efficiency was explored. Results: Verification and validation results suggested that the model is acceptably accurate. Minimal effect of pulse duration on coagulation depth was predicted at sub-ablative conditions. At those conditions, coagulation depth increased asymptotically to $90 mm with increasing pulse fluence. At ablative conditions, coagulation depth decreased asymptotically to 22-28 mm with increasing pulse irradiance. Ablation efficiency plateaued at high pulse fluences and long pulse durations. Mechanical properties were important as about 50% increase in coagulation depth and 25% decrease in ablation efficiency were predicted when considering the high strain-rate loading effect in comparison with quasi-static loading. Conclusions: Proper tuning of Er:YAG laser pulsing parameters can substantially improve its therapeutic outcomes. The effect of these parameters varies and depends on whether the laser-tissue conditions are ablative or sub-ablative.
2017 IEEE 13th International Colloquium on Signal Processing & its Applications (CSPA)
AIP Conference Proceedings
This paper presents engineering progress and the latest in-vitro and in-vivo results obtained wit... more This paper presents engineering progress and the latest in-vitro and in-vivo results obtained with a 4.0 MHz, 20 element, PZT annular transrectal HIFU array and several 4.0 MHz, 211 element, PZT and piezocomposite cylindrical transrectal HIFU arrays for the treatment of prostate cancer. The geometries of both arrays were designed and analyzed to steer the HIFU beams to the desired sites in the prostate volume using multi-channel electronic drivers, with the intent to increase treatment efficiency and reliability for the next generation of HIFU systems. The annular array is able to focus in depth from 25 mm to 50 mm, generate total acoustic powers in excess of 60W, and has been integrated into a modified Sonablate ® 500 HIFU system capable of controlling such an applicator through custom treatment planning and execution software. Both PZT-and piezocomposite cylindrical arrays were constructed and their characteristics were compared for the transrectal applications. These arrays have been installed into appropriate transducer housings, and have undergone characterization tests to determine their total acoustic power output, focusing range (in depth and laterally), focus quality, efficiency, and comparison tests to determine the material and technology of choice (PZT or piezocomposite) for intra-cavity HIFU applications. Array descriptions, characterization results, in-vitro and in-vivo results, and an overview of their intended use through the application software is shown.
Materials Research Innovations, 2006
IFMBE Proceedings, 2009
ABSTRACT This paper describes the design, construction, and evaluation of a three dimensional (3D... more ABSTRACT This paper describes the design, construction, and evaluation of a three dimensional (3D) ultrasound system to be used in the treatment of kidney tumors using high intensity focused ultrasound (HIFU). The system consists of a single element focused ultrasound transducer and a 3D positioning system. The single element ultrasound transducer (1 MHz) was bowl shaped with a geometric focus of 10 cm and was made from PZT4 material. The 3D positioning system was designed and built to move in polar coordinates. It has three stepper motors, some mechanical parts for support, and electronic circuits to control the movement of the motors and to control the on and off times of the transducer.
Journal of Medical Imaging and Health Informatics, 2011
Biomedical engineering online, Jan 17, 2005
Prostate cancer and benign prostatic hyperplasia are very common diseases in older American men, ... more Prostate cancer and benign prostatic hyperplasia are very common diseases in older American men, thus having a reliable treatment modality for both diseases is of great importance. The currently used treating options, mainly surgical ones, have numerous complications, which include the many side effects that accompany such procedures, besides the invasive nature of such techniques. Focused ultrasound is a relatively new treating modality that is showing promising results in treating prostate cancer and benign prostatic hyperplasia. Thus this technique is gaining more attention in the past decade as a non-invasive method to treat both diseases. In this paper, the design, construction and evaluation of a 1.75 dimensional ultrasound phased array to be used for treating prostate cancer and benign prostatic hyperplasia is presented. With this array, the position of the focus can be controlled by changing the electrical power and phase to the individual elements for electronically focusin...