View All Items

Title: Variations of Pericardial Dose at Different Respiratory Status in Accelerated Partial Breast Irradiation (APBI) Using Cyberknife M6™ Multileaf Collimators (CKMLC).
Creator: Long, Samanthia C., Shang, Charles, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The purpose of this study is to investigate the changes of the pericardial dose at different respiratory phases and statuses in accelerated partial breast irradiation (APBI) using Cyberknife M6™ multileaf collimators (CK-MLC). Anonymous 6 female patient files with respiration gated four-dimensional computed tomography (4DCT) sets, and 6 left breast cancer cases with CT images in free-breathing (FB) and deep inhalation breath-hold (BH) were selected. One CT image set from each patient was...
Show moreThe purpose of this study is to investigate the changes of the pericardial dose at different respiratory phases and statuses in accelerated partial breast irradiation (APBI) using Cyberknife M6™ multileaf collimators (CK-MLC). Anonymous 6 female patient files with respiration gated four-dimensional computed tomography (4DCT) sets, and 6 left breast cancer cases with CT images in free-breathing (FB) and deep inhalation breath-hold (BH) were selected. One CT image set from each patient was planned for APBI in Accuray Multiplan™ 5.2, and respectively compared its pericardial dose with those from CT sets of other respiratory phases. All the comparable CT images were fused in the planning system according to the left chest wall, among which the lung gap anterior to the pericardium varies by the lung expansion. For the purpose of this study, the tumor volume was outlined in the media-lower quadrant of the left breast where this lung gap is relatively small. All the plans in this study met the requirements set by the National Surgical Adjuvant Breast and Bowel Project/Radiation Therapy Oncology Group (NSABP/RTOG), specifically protocol B-39/RTOG 0413. From the comparisons in this investigation, the mean relative pericardial dose of the BH CT group showed significant or 45% (p < 0.01) lower value than that of FB CT group. However, in FB 4DCT group, 3 of 6 cases indicated a meaningful reduction (p < 0.05) in 100% inhalation phase when compared with the mean dose over other phases. The inconsistent pericardial doses were displayed in FB 4DCT group due to minimal changes in the anterior lung gap of the pericardium, when the diaphragmatic breathing was dominant in those patients.
Show less
Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004518, http://purl.flvc.org/fau/fd/FA00004518
Subject Headings: Breast--Cancer--Radiotherapy., Breast--Cancer--Treatment., Radiation--Measurement--Methodology., Medical physics.
Format: Document (PDF)

Title: The Advantages of Collimator Optimization for Intensity Modulated Radiation Therapy.
Creator: Doozan, Brian, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The goal of this study was to improve dosimetry for pelvic, lung, head and neck, and other cancers sites with aspherical planning target volumes (PTV) using a new algorithm for collimator optimization for intensity modulated radiation therapy (IMRT) that minimizes the x-jaw gap (CAX) and the area of the jaws (CAA) for each treatment field. A retroactive study on the effects of collimator optimization of 20 patients was performed by comparing metric results for new collimator optimization...
Show moreThe goal of this study was to improve dosimetry for pelvic, lung, head and neck, and other cancers sites with aspherical planning target volumes (PTV) using a new algorithm for collimator optimization for intensity modulated radiation therapy (IMRT) that minimizes the x-jaw gap (CAX) and the area of the jaws (CAA) for each treatment field. A retroactive study on the effects of collimator optimization of 20 patients was performed by comparing metric results for new collimator optimization techniques in Eclipse version 11.0. Keeping all other parameters equal, multiple plans are created using four collimator techniques: CA0, all fields have collimators set to 0°, CAE, using the Eclipse collimator optimization, CAA, minimizing the area of the jaws around the PTV, and CAX, minimizing the x-jaw gap. The minimum area and the minimum x-jaw angles are found by evaluating each field beam’s eye view of the PTV with ImageJ and finding the desired parameters with a custom script. The evaluation of the plans included the monitor units (MU), the maximum dose of the plan, the maximum dose to organs at risk (OAR), the conformity index (CI) and the number of fields that are calculated to split. Compared to the CA0 plans, the monitor units decreased on average by 6% for the CAX method with a p-value of 0.01 from an ANOVA test. The average maximum dose remained within 1.1% difference between all four methods with the lowest given by CAX. The maximum dose to the most at risk organ was best spared by the CAA method, which decreased by 0.62% compared to the CA0. Minimizing the x-jaws significantly reduced the number of split fields from 61 to 37. In every metric tested the CAX optimization produced comparable or superior results compared to the other three techniques. For aspherical PTVs, CAX on average reduced the number of split fields, lowered the maximum dose, minimized the dose to the surrounding OAR, and decreased the monitor units. This is achieved while maintaining the same control of the PTV.
Show less
Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004804, http://purl.flvc.org/fau/fd/FA00004804
Subject Headings: Radiation--Dosage., Optical engineering., Medical physics., Image-guided radiation therapy., Cancer--Radiotherapy., Medical radiology--Data processing., Medicine--Mathematical models.
Format: Document (PDF)

Title: Synthesis of Fluorogenic Probes Specific for Matrix Metalloproteinase 13.
Creator: Ibrahim, Mariam, Fields, Gregg B., Leventouri, Theodora, Florida Atlantic University, Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
Abstract/Description: Matrix Metalloproteinase-13 (MMP-13) belongs to a large family of proteolytic enzymes which are characterized by their ability to degrade the extracellular matrix components. MMP-13 appears to have a critical role in tumor invasion and metastasis. In this study, several fluorogenic probes specific for MMP-13 were designed and characterized. These synthesized probes could be modified with chelators to be applied for imaging MMP-13 in breast cancer and/or multiple myeloma models. The activity...
Show moreMatrix Metalloproteinase-13 (MMP-13) belongs to a large family of proteolytic enzymes which are characterized by their ability to degrade the extracellular matrix components. MMP-13 appears to have a critical role in tumor invasion and metastasis. In this study, several fluorogenic probes specific for MMP-13 were designed and characterized. These synthesized probes could be modified with chelators to be applied for imaging MMP-13 in breast cancer and/or multiple myeloma models. The activity and selectivity of MMP-13 and other MMPs against these probes were studied through two approaches. It was found that these probes were cleaved by all MMPs, but MMP-13 showed the highest activity and selectivity towards these peptides.
Show less
Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013507
Subject Headings: Matrix Metalloproteinases, Peptides, Fluorogenic probes
Format: Document (PDF)

Title: Prediction of Radiobiological Indices and Equivalent Uniform Dose in Lung Cancer Radiation Therapy using an Artificial Neural Network.
Creator: Pudasaini, Mukunda Prasad, Leventouri, Theodora, Muhammad, Wazir, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: In radiotherapy, radiobiological indices tumor control probability (TCP), normal tissue complication probability (NTCP), and equivalent uniform dose (EUD) are computed by analytical models. These models are rarely employed to rank and optimize treatment plans even though radiobiological indices weights more compared to dosimetric indices to reflect treatment goal. The objective of this study is to predict TCP, NTCP and EUDs for lung cancer radiotherapy treatment plans using an artificial...
Show moreIn radiotherapy, radiobiological indices tumor control probability (TCP), normal tissue complication probability (NTCP), and equivalent uniform dose (EUD) are computed by analytical models. These models are rarely employed to rank and optimize treatment plans even though radiobiological indices weights more compared to dosimetric indices to reflect treatment goal. The objective of this study is to predict TCP, NTCP and EUDs for lung cancer radiotherapy treatment plans using an artificial neural network (ANN). A total of 100 lung cancer patients’ treatment plans were selected for this study. Normal tissue complication probability (NTCP) of organs at risk (OARs) i.e., esophagus, spinal cord, heart and contralateral lung and tumor control probability (TCP) of treatment target volume (i.e., tumor) were calculated by the equivalent uniform dose (EUD) model. TCP/NTCP pairing with corresponding EUD are used individually as outputs for the neural network. The inputs for ANN are planning target volume (PTV), treatment modality, tumor location, prescribed dose, number of fractions, mean dose to PTV, gender, age, and mean doses to the OARs. The ANN is based on Levenberg-Marquardt algorithm with one hidden layer having 13 inputs and 2 outputs. 70% of the data was used for training, 15% for validation and 15% for testing the ANN. Our ANN model predicted TCP and EUD with correlation coefficient of 0.99 for training, 0.96 for validation, and 0.94 for testing. In NTCP and EUD prediction, averages of correlation coefficients are 0.94 for training, 0.89 for validation and 0.84 for testing. The maximum mean squared error (MSE) for the ANN is 0.025 in predicting the NTCP and EUD of heart. Our results show that an ANN model can be used with high discriminatory power to predict the radiobiological indices for lung cancer treatment plans.
Show less
Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014064
Subject Headings: Lungs--Cancer--Radiotherapy, Radiobiology, Neural networks (Computer science)
Format: Document (PDF)

Title: Potential Efficacy of the Monte Carlo Dose Calculations of 6MV Flattening Filter-Free Photon Beam of M6™ Cyberknife® System.
Creator: Neupane, Taindra, Shang, Charles, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: MapCheck measurements for 50 retrospective patient’s treatment plans suggested that MapCheck could be effectively employed in routine patient specific quality assurance in M6 Cyberknife with beams delivered at different treatment angles. However, these measurements also suggested that for highly intensity modulated MLC plans, field segments of width
Show moreMapCheck measurements for 50 retrospective patient’s treatment plans suggested that MapCheck could be effectively employed in routine patient specific quality assurance in M6 Cyberknife with beams delivered at different treatment angles. However, these measurements also suggested that for highly intensity modulated MLC plans, field segments of width < 8 mm should further be analyzed with a modified (-4%) correction factor. Results of MC simulations of the M6 Cyberknife using the EGSnrc program for 2-5 millions of incident particles in BEAMnrc and 10-20 millions in DOSXYZnrc have shown dose uncertainties within 2% for open fields from 7.6 x 7.7 mm2 to 100 x 100 mm2. Energy and corresponding FWHM were optimized by comparing with water phantom measurements at 800 mm SAD resulting to E = 7 MeV and FWHM = 2.2 mm. Good agreement of dose profiles (within 2%) and outputs (within 3%) were found between the MC simulations and water phantom measurements for the open fields.
Show less
Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013147
Subject Headings: Radiosurgery--Quality control, Monte Carlo method, Radiation dosimetry
Format: Document (PDF)

Title: Phantom Study Incorporating A Diode Array Into The Treatment Planning System For Patient-Specific Quality Assurance.
Creator: Curley, Casey Michael, Leventouri, Theodora, Ouhib, Zoubir, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The purpose of this research is to accurately match the calculation environment, i.e. the treatment planning system (TPS) with the measurement environment (using a 2-D diode array) for lung Stereotactic Body Radiation Therapy (SBRT) patient-specific quality assurance (QA). Furthermore, a new phantom was studied in which the 2-D array and heterogeneities were incorporated into the patient-specific QA process for lung SBRT. Dual source dual energy computerized tomography (DSCT) and single...
Show moreThe purpose of this research is to accurately match the calculation environment, i.e. the treatment planning system (TPS) with the measurement environment (using a 2-D diode array) for lung Stereotactic Body Radiation Therapy (SBRT) patient-specific quality assurance (QA). Furthermore, a new phantom was studied in which the 2-D array and heterogeneities were incorporated into the patient-specific QA process for lung SBRT. Dual source dual energy computerized tomography (DSCT) and single energy computerized tomography (SECT) were used to model phantoms incorporating a 2-D diode array into the TPS. A water-equivalent and a heterogeneous phantom (simulating the thoracic region of a patient) were studied. Monte Carlo and pencil beam dose distributions were compared to the measured distributions. Composite and individual fields were analyzed for normally incident and planned gantry angle deliveries. The distributions were compared using γ-analysis for criteria 3% 3mm, 2% 2mm, and 1% 1mm. The Monte Carlo calculations for the DSCT modeled phantoms (incorporating the array) showed an increase in the passing percentage magnitude for 46.4 % of the fields at 3% 3mm, 85.7% at 2% 2mm, and 92.9% at 1% 1mm. The Monte Carlo calculations gave no agreement for the same γ-analysis criteria using the SECT. Pencil beam calculations resulted in lower passing percentages when the diode array was incorporated in the TPS. The DSCT modeled phantoms (incorporating the array) exhibited decrease in the passing percentage magnitude for 85.7% of the fields at 3% 3mm, 82.1% at 2% 2mm, and 71.4% at 1% 1mm. In SECT modeled phantoms (incorporating the array), a decrease in passing percentage magnitude were found for 92.9% of the fields at 3% 3mm, 89.3% at 2% 2mm, and 82.1% at 1% 1mm. In conclusion, this study demonstrates that including the diode array in the TPS results in increased passing percentages when using a DSCT system with a Monte Carlo algorithm for patient-specific lung SBRT QA. Furthermore, as recommended by task groups (e.g. TG 65, TG 101, TG 244) of the American Association of Physicists in Medicine (AAPM), pencil beam algorithms should be avoided in the presence of heterogeneous materials, including a diode array.
Show less
Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004744, http://purl.flvc.org/fau/fd/FA00004744
Subject Headings: Cancer--Radiotherapy., Lungs--Cancer--Treatment., Monte Carlo method., Proton beams., Image-guided radiation therapy., Ion bombardment., Medical physics.
Format: Document (PDF)

Title: Optimization of Computed Tomography Calibration Curve for Proton Therapy Treatment Planning.
Creator: Ghasemi Ghonchehnazi, Maryam, Shang, Charles, Leventouri, Theodora, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: The accuracy of proton dose computation in the treatment planning system relies on the conversion from the Hounsfield units (HU) of each voxel in the patient CT scan to the proton stopping power ratio (SPR). The aim of this study is to investigate the potential improvement in determining proton SPR using single energy computed tomography (SECT) to reduce the uncertainty in predicting the proton range in patients. Factors which may cause CT number variations in the calibration curve have been...
Show moreThe accuracy of proton dose computation in the treatment planning system relies on the conversion from the Hounsfield units (HU) of each voxel in the patient CT scan to the proton stopping power ratio (SPR). The aim of this study is to investigate the potential improvement in determining proton SPR using single energy computed tomography (SECT) to reduce the uncertainty in predicting the proton range in patients. Factors which may cause CT number variations in the calibration curve have been examined. The HU-SPR calibration curve was determined based on HU of human body tissues using the stoichiometric method. The uncertainties in SPR were divided into two major categories: The inherent uncertainty, and the CT number uncertainty. The root mean square errors of the inherent uncertainties were estimated 0.02%, 0.61% and 0.26% for lung tissues, soft tissues (excluding Thyroid), and bone tissues, respectively. The total uncertainties due to the inherent uncertainty and CT imaging errors were estimated 1.50%. The average calibration curve of two sized phantoms (head and body) were used in the treatment planning system to mitigate beam hardening effect through the attenuating media. A higher accuracy of the SPR prediction using the stoichiometric method is suggested through comparison with the predicted SPRs that derived from the direct calibration approach.
Show less
Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013374
Subject Headings: Proton Therapy, Tomography, Calibration, Tomography, X-Ray Computed
Format: Document (PDF)

Title: Investigation of Rotational Deviations on Single Fiducial Tumor Tracking with Simulated Respiratory Motion using Synchrony® Respiratory Motion Tracking for Cyberknife® Treatment.
Creator: Christ, Zachary A., Shang, Charles, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: It is hypothesized that the uncertainty of the Synchrony® model from the rotation of a geometrically asymmetrical single fiducial shall be non-zero during the motion tracking. To validate this hypothesis, the uncertainty was measured for a Synchrony® model built for a respiratory motion phantom oriented at different yaw angles on a Cyberknife® treatment table. A Mini-ball Cube with three cylindrical GoldMark™ (1mmx5mm Au) numbered fiducials was placed inside a respiratory phantom and used for...
Show moreIt is hypothesized that the uncertainty of the Synchrony® model from the rotation of a geometrically asymmetrical single fiducial shall be non-zero during the motion tracking. To validate this hypothesis, the uncertainty was measured for a Synchrony® model built for a respiratory motion phantom oriented at different yaw angles on a Cyberknife® treatment table. A Mini-ball Cube with three cylindrical GoldMark™ (1mmx5mm Au) numbered fiducials was placed inside a respiratory phantom and used for all tests. The fiducial with the least artifact interference was selected for the motion tracking. A 2cm periodic, longitudinal, linear motion of the Mini-ball cube was executed and tested for yaw rotational angles, 0° – 90°. The test was repeated over 3 nonconsecutive days. The uncertainty increased with the yaw angle with the most noticeable changes seen between20° and 60° yaw, where uncertainty increased from 23.5% to 57.9%. A similar test was performed using a spherical Gold Anchor™ fiducial. The uncertainties found when using the Gold Anchor™ were statistically lower than those found when using the GoldMark™ fiducial for all angles of rotation. For the first time, it is found that Synchrony® model uncertainty depends on fiducial geometry. In addition, this research has shown that tracking target rotation using a single fiducial can be accomplished with the Synchrony® model uncertainty as it is displayed on the treatment console. The results of this research could lead to decreased acute toxicity effects related to multiple fiducials.
Show less
Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013041
Subject Headings: Fiducial Markers, Radiosurgery--Quality control, Robotic radiosurgery
Format: Document (PDF)

Title: Improving the Mechanical Properties of Nano-Hydroxyapatite.
Creator: Khanal, Suraj P., Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Hydroxyapatite (HAp) is an ideal bioactive material that is used in orthopedics. Chemical composition and crystal structure properties of HAp are similar to the natural bone hence it promotes bone growth. However, its mechanical properties of synthetic HAp are not sufficient for major load-bearing bone replacement. The potential of improving the mechanical properties of synthetic hydroxyapatite (HAp) by incorporating carboxyl functionalized single walled carbon nanotubes (CfSWCNT) and...
Show moreHydroxyapatite (HAp) is an ideal bioactive material that is used in orthopedics. Chemical composition and crystal structure properties of HAp are similar to the natural bone hence it promotes bone growth. However, its mechanical properties of synthetic HAp are not sufficient for major load-bearing bone replacement. The potential of improving the mechanical properties of synthetic hydroxyapatite (HAp) by incorporating carboxyl functionalized single walled carbon nanotubes (CfSWCNT) and polymerized ɛ-caprolactam (nylon) is studied. The fracture toughness, tensile strength, Young’s modulus, stiffness and fracture energy were studied for a series of HAp samples with CfSWCNT concentrations varying from 0 to 1.5 wt. % without, and with nylon addition. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Differential Scanning Calorimetry (DSC) were used to characterize the samples. The fracture toughness and tensile test was performed under the standard protocol of ASTM D5045 and ASTM D638-02a respectively. Reproducible maximum values of (3.60 ± 0.3) MPa.m1/2 for fracture toughness and 65.38 MPa for tensile strength were measured for samples containing 1 wt. % CfSWCNT and nylon. The Young’s modulus, stiffness and fracture energy of the samples are 10.65 GPa, 1482.12 N/mm, and 644 J/m2 respectively. These values are comparable to those of the cortical bone. Further increase of the CfSWCNT content results to a decreased fracture toughness and tensile strength and formation of a secondary phase.
Show less
Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004675, http://purl.flvc.org/fau/fd/FA00004675
Subject Headings: Biomedical engineering -- Materials, Biomedical materials -- Mechanical properties, Nanostructured materials -- Mechanical properties
Format: Document (PDF)

Title: Enhancement in Low-Dose Computed Tomography through Image Denoising Techniques: Wavelets and Deep Learning.
Creator: Mohammadi Khoroushadi, Mohammad Sadegh, Leventouri, Theodora, Zhuang, Hanqi, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Reducing the amount of radiation in X-ray computed tomography has been an active area of research in the recent years. The reduction of radiation has the downside of degrading the quality of the CT scans by increasing the ratio of the noise. Therefore, some techniques must be utilized to enhance the quality of images. In this research, we approach the denoising problem using two class of algorithms and we reduce the noise in CT scans that have been acquired with 75% less dose to the patient...
Show moreReducing the amount of radiation in X-ray computed tomography has been an active area of research in the recent years. The reduction of radiation has the downside of degrading the quality of the CT scans by increasing the ratio of the noise. Therefore, some techniques must be utilized to enhance the quality of images. In this research, we approach the denoising problem using two class of algorithms and we reduce the noise in CT scans that have been acquired with 75% less dose to the patient compared to the normal dose scans. Initially, we implemented wavelet denoising to successfully reduce the noise in low-dose X-ray computed tomography (CT) images. The denoising was improved by finding the optimal threshold value instead of a non-optimal selected value. The mean structural similarity (MSSIM) index was used as the objective function for the optimization. The denoising performance of combinations of wavelet families, wavelet orders, decomposition levels, and thresholding methods were investigated. Results of this study have revealed the best combinations of wavelet orders and decomposition levels for low dose CT denoising. In addition, a new shrinkage function is proposed that provides better denoising results compared to the traditional ones without requiring a selected parameter. Alternatively, convolutional neural networks were employed using different architectures to resolve the same denoising problem. This new approach improved denoising even more in comparison to the wavelet denoising.
Show less
Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013115
Subject Headings: Tomography--Image quality, Wavelets (Mathematics), Deep learning, Tomography, X-Ray Computed
Format: Document (PDF)

Title: Efficacy of the virtual cone method using fixed small multi-leaf collimator field for stereotactic radiosurgery.
Creator: Neupane, Taindra, Leventouri, Theodora, Shang, Charles, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: Dosimetric uncertainty in very small (
Show moreDosimetric uncertainty in very small (< 2 x 2 cm2) photon fields is notably higher that has created research questions when using small-field virtual cone with variable multileaf collimator (MLC) fields. We evaluate the efficacy of the virtual cone with a fixed MLC field for stereotactic radiosurgery (SRS) of small targets such as trigeminal neuralgia. We employed a virtual cone technique with a fixed field geometry, called fixed virtual cone (fVC), for small target radiosurgery using the EDGE (Varian Medical Systems, Palo Alto, CA) linac. The fVC is characterized by 0.5 cm x 0.5 cm high-definition MLC field of 10 MV flattening filter-free (FFF) beam defined at 100 cm SAD, while jaws are positioned at 1.5 cm x 1.5 cm. A spherical dose distribution equivalent to 5 mm cone was generated by using 10–14 non-coplanar partial arcs. The dosimetric accuracy of this technique was validated using the SRS MapCHECK (Sun Nuclear Corporation, FL) and the EBT3 (Ashland Inc., NJ) film based on absolute dose measurements. For the quality assurance (QA), 10 treatment plans for trigeminal neuralgia consisting of various arc fields at different collimator angles were analyzed retrospectively using 6 MV and 10 MV FFF beams, including the field-by-field study (n = 130 fields). Dose outputs were compared between the SRS MapCHECK measurements and Eclipse treatment planning system (TPS) with Acuros XB algorithm (version 16.1). In addition, important clinical parameters of 15 cases treated for trigeminal neuralgia were evaluated for the clinical performance. Moreover, dosimetric (field output factors, dose/MU) uncertainties considering a minute (± 0.5–1.0 mm) leaf shift in the field defining fVC, were examined from the TPS, SRS diode (PTW 60018) measurements, and Monte Carlo (MC) simulations.
Show less
Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00013958
Subject Headings: Radiation dosimetry, Radiosurgery, Collimators (Optical instrument), Monte Carlo method
Format: Document (PDF)

Title: Effect of Processing Temperature on the Properties of Nanophase Fe-substituted Hydroxypatite.
Creator: Kathriarachchi, Vindu, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The effect of processing temperature on the crystal structure properties of the Fe-substituted Hydroxyapatite (Fe-HAp) was studied by using the Rietveld refinement method of powder x-ray (XRD) and neutron diffraction (NPD) patterns. Superconducting QUantum Interference Device (SQUID) magnetometry, transmission electron microscopy (TEM) and x-ray fluorescence spectroscopy (XRF) were used to study the magnetic properties, particle morphology and chemical composition of the prepared samples. Two...
Show moreThe effect of processing temperature on the crystal structure properties of the Fe-substituted Hydroxyapatite (Fe-HAp) was studied by using the Rietveld refinement method of powder x-ray (XRD) and neutron diffraction (NPD) patterns. Superconducting QUantum Interference Device (SQUID) magnetometry, transmission electron microscopy (TEM) and x-ray fluorescence spectroscopy (XRF) were used to study the magnetic properties, particle morphology and chemical composition of the prepared samples. Two sets of samples of chemical formula Ca5-xFex(PO4)3OH were prepared with x = 0, 0.05, 0.1, 0.2 and 0.3 by using processing temperatures of 37°C and 80°C, following a two-step co-precipitation method. A single phase HAp was identified in samples with x = 0 and 0.05. Processing temperature affects the type and percentage of secondary phases: hematite was detected in samples prepared at 37°C with x ≥ 0.1, hematite and maghemite were detected in samples prepared at 80°C with x = 0.2 and 0.3. Rietveld refinements of NPD and XRD patterns showed that the a lattice constants are greater in Fe-substituted samples prepared at 37°C, whereas the c lattice constants are greater in the 80°C samples for x ≥ 0.05. Fe preferentially substitutes at the Ca2 site in the 80°C samples, whereas Ca1 is the preferred substitution site in the 37°C samples. Fe substitution results to a decrease of the lattice constants at both preparation temperatures. The ratios Fe/(Fe + Ca) of the refined atomic fractions of the samples prepared at 80°C are greater than those of the 37°C samples. Further, more secondary phases form in samples prepared at 37°C compared to 80°C samples. The magnetic measurements reveal that pure HAp is diamagnetic, whereas samples with x = 0.05 and 0.1 are paramagnetic. Samples with x = 0.3 showed superparamagnetic behavior based on ZFC and FC measurements. Similar hysteresis loops in samples x = 0.2 and 0.3 indicate that the samples with x = 0.2 may show superparamagnetic properties. For x = 0.2 and 0.3, the samples prepared at 80°C showed higher magnetization compared to the 37°C samples, because of the maghemite secondary phase. Based on the TEM images, Fe substituted HAp nanoparticles prepared at 37°C are mainly spherically shaped, and the 80°C particles are mainly elongated. Increase of the Fe concentration favors formation of elongated particles and larger spherical particles. The XRF measurements confirm the Fe for Ca substitution in the HAp structure based on the decrease of the Ca/P and the increase of the Fe/(Fe + Ca) atomic ratios with the Fe concentration.
Show less
Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004512, http://purl.flvc.org/fau/fd/FA00004512
Subject Headings: Biomedical materials, Nanostructured materials -- Environmental aspects, Nanostructured materials -- Mechanical properties, Pharmaceutical biotechnology, Rietveld method
Format: Document (PDF)

Title: Dosimetric and Radiobiological Plan Evaluation Parameters for Fractionated High-Dose Rate GYN Brachytherapy.
Creator: Shojaei, Marjan, Pella, Silvia, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Intracavitary high-dose-rate brachytherapy (HDRBT) is a treatment option for endometrial cancer, depending on the cancer stage. Because of the steep high dose gradient of HDRBT, very small differences in the treatment plans, surrounding organ’s anatomy, or procedures during the treatment could potentially cause significant dose variation to the tumor, as well as organs at risks (OAR) nearby the treatment area, which could result in unwanted radiobiological side effects. In this retrospective...
Show moreIntracavitary high-dose-rate brachytherapy (HDRBT) is a treatment option for endometrial cancer, depending on the cancer stage. Because of the steep high dose gradient of HDRBT, very small differences in the treatment plans, surrounding organ’s anatomy, or procedures during the treatment could potentially cause significant dose variation to the tumor, as well as organs at risks (OAR) nearby the treatment area, which could result in unwanted radiobiological side effects. In this retrospective study, the radiobiological plan evaluation parameters Equivalent Uniform Dose (EUD), Normal Tissue Complication Probability (NTCP) are used as assessment tools to evaluate HDRBT plans. Furthermore, gynecological applicator position in the coordinate system, and possible dose variations to the tumor and critical organs from the initial fraction in comparison with subsequent fractions over the entire multi fractionated treatment are studied. The evaluations were performed for 118 HDR treatment plans for 30 patients by registration of the subsequent treatment plans into the initial CT-image guided plan. Dose fractionation regimens varied from 4Gy to 7Gy per fraction, 1 or 2 fractions per week, depending on the cancer stage. Our results demonstrate no significant radiobiological impacts on organs at risks (OAR). In addition, the results of the applicator positions’ study indicate that improvement of immobilization and localization devices are recommended.
Show less
Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013144
Subject Headings: Brachytherapy, Radiobiology, Radiation dosimetry--Evaluation
Format: Document (PDF)

Title: Dosimetric and Radiobiological Comparison of the Effects of High Definition versus Normal Collimation on Treatment Plans for Stereotactic Lung Cancer Radiation Therapy.
Creator: Pudasaini, Mukunda Prasad, Pella, Silvia, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Stereotactic Body Radiation Therapy (SBRT) is a modern precision radiation therapy to deliver the dose in 1 to 5 fractions with high target dose conformity, and steep dose gradient towards healthy tissues. The dose delivered is influenced by the leaf width of the MLC, especially in case of SBRT. Treatment plans with high definition (HD) MLC having leaf-width 2.5 mm and normal MLC having leaf-width 5 mm, were compared to quantify dosimetric and radiobiological parameters. Dosimetric parameters...
Show moreStereotactic Body Radiation Therapy (SBRT) is a modern precision radiation therapy to deliver the dose in 1 to 5 fractions with high target dose conformity, and steep dose gradient towards healthy tissues. The dose delivered is influenced by the leaf width of the MLC, especially in case of SBRT. Treatment plans with high definition (HD) MLC having leaf-width 2.5 mm and normal MLC having leaf-width 5 mm, were compared to quantify dosimetric and radiobiological parameters. Dosimetric parameters conformity indices (CI), gradient indices (GI) and heterogeneity indices (HI) were compared. The radiobiological parameters were evaluated by normal tissue complication probability (NTCP) and tumor control probability (TCP) based on the equivalent uniform dose (EUD). The results show that there is dosimetric and radiobiological merit of the HD MLC over the normal MLC. However, the improvement is not consistent with all the plans and thus further research is required prior to conclusion.
Show less
Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013148
Subject Headings: Radiosurgery, Lung Neoplasms, Radiation dosimetry, Radiobiology
Format: Document (PDF)

Title: Dosimetric and Radiobiological Comparison of Forward Tangent Intensity Modulated Radiation Therapy (FT-IMRT) and Volumetric Modulated Arc Therapy (VMAT) for Early Stage Whole Breast Cancer.
Creator: Moshiri Sedeh, Nader, Pella, Silvia, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Intensity Modulated Radiation Therapy (IMRT) is a well-known type of external beam radiation therapy. The advancement in technology has had an inevitable influence in radiation oncology as well that has led to a newer and faster dose delivery technique called Volumetric Modulated Arc Therapy (VMAT). Since the presence of the VMAT modality in clinics in the late 2000, there have been many studies in order to compare the results of the VMAT modality with the current popular modality IMRT for...
Show moreIntensity Modulated Radiation Therapy (IMRT) is a well-known type of external beam radiation therapy. The advancement in technology has had an inevitable influence in radiation oncology as well that has led to a newer and faster dose delivery technique called Volumetric Modulated Arc Therapy (VMAT). Since the presence of the VMAT modality in clinics in the late 2000, there have been many studies in order to compare the results of the VMAT modality with the current popular modality IMRT for various tumor sites in the body such as brain, prostate, head and neck, cervix and anal carcinoma. This is the first study to compare VMAT with IMRT for breast cancer. The results show that the RapidArc technique in Eclipse version 11 does not improve all aspects of the treatment plans for the breast cases automatically and easily, but it needs to be manipulated by extra techniques to create acceptable plans thus further research is needed.
Show less
Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004526, http://purl.flvc.org/fau/fd/FA00004526
Subject Headings: Breast -- Cancer -- Treatment, Cancer -- Radiation therapy, Image guided radiation therapy, Radiation dosimetry, Radiotherapy -- Technological innovations
Format: Document (PDF)

Title: Dose Validation for Partial Accelerated Breast Irradiation treated with the SAVI Applicator.
Creator: Pinder, Janeil K., Pella, Silvia, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The purpose of this study is to verify and validate the dose at various points of interest in accelerated partial breast irradiation (APBI) treated with the Strut Adjusted Volume Implant (SAVI) applicator using Thermoluminescent Dosimeters (TLDs). A set of CT images were selected from a patient’s data who had received APBI using the SAVI applicator. The images were used to make 3D models. TLDs were calibrated for Brachytherapy. Various points of interest were marked out and slots were carved...
Show moreThe purpose of this study is to verify and validate the dose at various points of interest in accelerated partial breast irradiation (APBI) treated with the Strut Adjusted Volume Implant (SAVI) applicator using Thermoluminescent Dosimeters (TLDs). A set of CT images were selected from a patient’s data who had received APBI using the SAVI applicator. The images were used to make 3D models. TLDs were calibrated for Brachytherapy. Various points of interest were marked out and slots were carved in the 3D models to fit the TLDs. CT scans were taken of the 3D models with expanded SAVI applicator inserted. A plan was made following B-39 protocol. The TLDs were read and the absorbed doses were calculated and compared to the delivered doses. The results of this study show that the overall average reading of the TLDs is within expected value. The TPS shows overestimated dose calculations for brachytherapy.
Show less
Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00005942
Subject Headings: Dissertations, Academic -- Florida Atlantic University, Thermoluminescence dosimetry., Brachytherapy., Radiotherapy Dosage., Breast--Cancer--Radiotherapy.
Format: Document (PDF)

Title: Development of an Arduino-based 3D printed 6DOF robotic phantom and a MATLAB-based software for Radiation Therapy Quality Assurance.
Creator: Rahman, Md Mushfiqur, Leventouri, Theodora, Shang, Charles, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Quality Assurance (QA) for medical linear accelerators (linac) is the primary concern in external beam radiation therapy. In this research, we have developed a MATLAB-based software named Quality Assurance for Linacs (QALMA), which is unique, due to cost-effectiveness, user friendly interface, and customizability. It includes five modules to perform different QA tests: Star Shot analysis, Picket Fence test, Winston-Lutz test, MLC log file analysis, and verification of light & radiation field...
Show moreQuality Assurance (QA) for medical linear accelerators (linac) is the primary concern in external beam radiation therapy. In this research, we have developed a MATLAB-based software named Quality Assurance for Linacs (QALMA), which is unique, due to cost-effectiveness, user friendly interface, and customizability. It includes five modules to perform different QA tests: Star Shot analysis, Picket Fence test, Winston-Lutz test, MLC log file analysis, and verification of light & radiation field coincidence. We also pay attention to quality assurance of 6DOF treatment couch that plays a very important role in radiation therapy. We developed an Arduino based 3D printed 6DOF robotic phantom to check the accuracy of the treatment couch. This robotic phantom was experimentally validated under clinical standards, and customizable upon requirements of the quality assurance Task. The current features of this robotic phantom open development opportunities beyond the specific couch application, such as organs motion simulation.
Show less
Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013165
Subject Headings: Radiation therapy, Radiotherapy--Quality control, Arduino (Computer language), MATLAB
Format: Document (PDF)

Title: CONSISTENCY OF CT NUMBER AND ELECTRON DENSITY IN TREATMENT PLANNING SYSTEM VERSUS CT SCANNER, AND DOSIMETRIC CONSEQUENCES.
Creator: Hana, Evan Makdasy, Pella, Silvia, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The Computer Tomography (CT) scanned images are very important for the Treatment Planning System (TPS) to provide the electron density of the different types of tissues that the radiation penetrates in the path to the tumor to be treated. This electron density is converted to an attenuation coefficient, which varies with tissue for each structure and even varies by the tissue volume. The purpose of this research is to evaluate the CT numbers, and convert them into relative electron densities....
Show moreThe Computer Tomography (CT) scanned images are very important for the Treatment Planning System (TPS) to provide the electron density of the different types of tissues that the radiation penetrates in the path to the tumor to be treated. This electron density is converted to an attenuation coefficient, which varies with tissue for each structure and even varies by the tissue volume. The purpose of this research is to evaluate the CT numbers, and convert them into relative electron densities. Twenty-five patients’ data and CT numbers were evaluated in the CT scanner and in Eclipse and were converted into relative electron density and compared with each other. The differences between the relative electron density in the Eclipse was found to be from 0 up to 6% between tissue equivalent materials, the final result for all equivalent tissue materials was about 2%. For the patients’ data, the percentage difference of CT number versus electron density was found to be high for high relative electron density organs, namely the final average result for the spine was 8%, less for pelvis, and less for rib while for the other organs it was even less. The very lowest was 0.3% compared with 1% which is acceptable for clinical standards.
Show less
Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013315
Subject Headings: Tomography, X-Ray Computed, Electron density, Radiation dosimetry--Evaluation, Tomography Scanners, X-Ray Computed
Format: Document (PDF)

Title: Comparison of Measured and Computed Lateral Penumbra for a ProteusPlus Pencil Beam Scanning Proton Therapy System.
Creator: Leyva, Michael, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The lateral penumbra of a proton pencil beam scanning system (PBS) is of great importance in sparing of organs at risk and normal tissue when treating patients. The purpose of this current work is to measure the lateral penumbra of the Ion Beam Applications (Ion Beam Applications, Louvain‐la‐Neuve, Belgium) ProteusPLUS PBS Proton Therapy System and compare the measurements with the computed results from the RayStation proton treatment planning system. The lateral penumbra (80%-20%) was...
Show moreThe lateral penumbra of a proton pencil beam scanning system (PBS) is of great importance in sparing of organs at risk and normal tissue when treating patients. The purpose of this current work is to measure the lateral penumbra of the Ion Beam Applications (Ion Beam Applications, Louvain‐la‐Neuve, Belgium) ProteusPLUS PBS Proton Therapy System and compare the measurements with the computed results from the RayStation proton treatment planning system. The lateral penumbra (80%-20%) was measured using EBT-3 Gafchromic film in the water tank. The lateral penumbra was studied for various parameters such as range, depth, and air gap. The computed lateral penumbra was found to be higher than the measured lateral penumbra by up to 2.3 mm in the case of depth dependency at 30 cm, and lower by up to 1.18 mm in the case of an air gap of 15 cm.
Show less
Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013229
Subject Headings: Proton Therapy, Radiotherapy--Measurement, Radiotherapy Planning, Computer-Assisted
Format: Document (PDF)

Title: COMPARATIVE PHARMACOKINETICS, BIODISTRIBUTION AND DOSIMETRY OF 212Pb (ALPHA-EMITTER) LABELED ANTIBODY VS PEPTIDE VS SMALL MOLECULE.
Creator: Moshiri, Nader Sedeh, Leventouri, Theodora, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: With the advent of newly and more reliably designed targeted therapy methods in the past several years, targeted radionuclide therapy has attracted more attentions around the world as a more reliable treatment modality in combination with other well established traditional cancer treatments i.e., external beam radiotherapy and chemotherapy. Alpha particles have a high relative biological effectiveness (RBE) due to their high linear energy transfer (LET). However, to utilize them for...
Show moreWith the advent of newly and more reliably designed targeted therapy methods in the past several years, targeted radionuclide therapy has attracted more attentions around the world as a more reliable treatment modality in combination with other well established traditional cancer treatments i.e., external beam radiotherapy and chemotherapy. Alpha particles have a high relative biological effectiveness (RBE) due to their high linear energy transfer (LET). However, to utilize them for therapeutic purposes, precise human body dosimetry calculation is required. The measurement of their uptake and biodistribution can be quite challenging. Also, due to the complex biology of different types of cells, their shapes and functions, there is not a simple and clear understanding of the mechanism of action that fits all. This study aims to estimate and compare the human organ dosimetry of the alpha emitter, 212Pb, from animal data assuming that it is conjugated with three different types of commonly used targeting nanoparticles. For this purpose, the pre-published animal data of three different radionuclide labeled peptide, antibody, and small molecule carriers were selected and converted to human data. Then a compartmental model was designed for each of them to fit the model to the human data with 212Pb, half-life of 10.64 hours. Once each model reached the desired fit, the area under the curves were extracted then the estimated human organ dosimetry calculations took place via the MIRD scheme. The organ dosimetry results for 212Pb + three different carriers are presented in Tables 14, 17, and 20.
Show less
Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014215
Subject Headings: Cancer--Treatment, Lead-212, Nuclear Medicine
Format: Document (PDF)

Medical physics. (3)	+ -
Radiation dosimetry (3)	+ -
Radiobiology (3)	+ -
Tomography, X-Ray Computed (3)	+ -
Breast--Cancer--Radiotherapy. (2)	+ -

Cancer--Radiotherapy. (2)	+ -
Image-guided radiation therapy. (2)	+ -
Monte Carlo method (2)	+ -
Proton Therapy (2)	+ -
Radiation dosimetry--Evaluation (2)	+ -
Radiosurgery (2)	+ -
Radiosurgery--Quality control (2)	+ -
Annealing algorithm (1)	+ -
Arduino (Computer language) (1)	+ -
Biomedical engineering -- Materials (1)	+ -
Biomedical materials (1)	+ -
Biomedical materials -- Mechanical properties (1)	+ -
Brachytherapy (1)	+ -
Brachytherapy. (1)	+ -
Breast--Cancer--Treatment. (1)	+ -
Breast -- Cancer -- Treatment (1)	+ -
Calibration (1)	+ -
Cancer--Treatment (1)	+ -
Cancer -- Radiation therapy (1)	+ -
Collimators (Optical instrument) (1)	+ -
Deep learning (1)	+ -
Dissertations, Academic -- Florida Atlantic University (1)	+ -
Electron density (1)	+ -
Fiducial Markers (1)	+ -
Fluorogenic probes (1)	+ -

Florida Atlantic University (21)	+ -
Department of Physics (20)	+ -
Shang, Charles (6)	+ -
Pella, Silvia (5)	+ -
Neupane, Taindra (2)	+ -

Pudasaini, Mukunda Prasad (2)	+ -
Christ, Zachary A. (1)	+ -
Curley, Casey Michael (1)	+ -
Department of Chemistry and Biochemistry (1)	+ -
Doozan, Brian (1)	+ -
Fields, Gregg B. (1)	+ -
Galanakou, Panagiota (1)	+ -
Ghasemi Ghonchehnazi, Maryam (1)	+ -
Hana, Evan Makdasy (1)	+ -
Ibrahim, Mariam (1)	+ -
Kathriarachchi, Vindu (1)	+ -
Khanal, Suraj P. (1)	+ -
Leyva, Michael (1)	+ -
Long, Samanthia C. (1)	+ -
Mohammadi Khoroushadi, Mohammad Sadegh (1)	+ -
Moshiri Sedeh, Nader (1)	+ -
Moshiri, Nader Sedeh (1)	+ -
Muhammad, Wazir (1)	+ -
Ouhib, Zoubir (1)	+ -
Pinder, Janeil K. (1)	+ -
Rahman, Md Mushfiqur (1)	+ -
Shojaei, Marjan (1)	+ -
Zhuang, Hanqi (1)	+ -

Search In

Pages

Pages

Sort Results By:

Narrow results by:

Collection

Topical Subject

Genre

Type of Resource

Language

Creator

Format

Owner