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Title: Nuclear Halo Effect and Field Size Factor for Pencil-Beam Scanning Proton Therapy.
Creator: Beqiri, Atdhe, Shang, Charles, Muhammad, Wazir, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: In proton therapy systems with pencil-beam scanning, output of Halo effect is not necessarily included in Treatment Planning System (TPS). Halo effect (low-intensity tail) can significantly affect a patient’s dose distribution. The output of this dose depends on the field size being irradiated. Although much research has been made to investigate such relation to the field size, the number of reports on dose calculations including the halo effect is small. In this work we have investigated the...
Show moreIn proton therapy systems with pencil-beam scanning, output of Halo effect is not necessarily included in Treatment Planning System (TPS). Halo effect (low-intensity tail) can significantly affect a patient’s dose distribution. The output of this dose depends on the field size being irradiated. Although much research has been made to investigate such relation to the field size, the number of reports on dose calculations including the halo effect is small. In this work we have investigated the Halo effect, including field size factor, target depth factor, and air gaps with a range shifter for a Varian ProBeam. Dose calculations created on the Eclipse Treatment Planning System (vs15.6 TPS) are compared with plane-parallel ionization chambers (PTW Octavius 1500) measurements using PCS and AcurosPT MC model in different isocenters: 5cm, 10cm, and 20cm. We find that in AcurosPT algorithm deviations range between -7.53% (for 2cm field in 25cm air gap with range shifter) up to +7.40% (for 20cm field in 15cm air gap with range shifter). Whereas, in PCS algorithm the deviations are -2.07% (for 20x20cm field in open conditions) to -6.29% (for 20x20cm field in 25cm air gap with range shifter).
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Date Issued: 2021
PURL: http://purl.flvc.org/fau/fd/FA00013788
Subject Headings: Proton Therapy, Proton beams, Radiotherapy
Format: Document (PDF)

Title: Commissioning of 360⁰ Rotational Single Room ProBeam Compact™ (Varian Medical) Pencil Beam Scanning Proton Therapy System.
Creator: Fathallah, Shreen Mohamed, Shang, Charles, Muhammad, Wazir, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: A clinical commissioning of the first 360 rotational compact Varian ProBeam scanning proton pencil beam (Varian Medical, Palo Alto, CA) system was conducted at the South Florida Proton Therapy Institute (SFPTI). The beam dosimetry and characterizations were the vital section used to verify the consistency of the treatment planning system (TPS) outputs. The integrated depth dose curves were acquired with AP CAX in water phantom utilizing a large PTW Bragg peak chamber; the dose output factors...
Show moreA clinical commissioning of the first 360 rotational compact Varian ProBeam scanning proton pencil beam (Varian Medical, Palo Alto, CA) system was conducted at the South Florida Proton Therapy Institute (SFPTI). The beam dosimetry and characterizations were the vital section used to verify the consistency of the treatment planning system (TPS) outputs. The integrated depth dose curves were acquired with AP CAX in water phantom utilizing a large PTW Bragg peak chamber; the dose output factors measurements were performed by using IBA PCC05 chamber at 1.5 cm water depth applying a single layer 10×10 cm2 beams and 1.1 RBE offset as recommended in TRS 398 report. Widths of the Bragg peaks ranges (Rb80-Ra80) were from 4.07 cm to 30.51 cm for the energy range 70 MeV to 220 MeV. Beam optics such as spot sizes and spot profiles were acquired in-air by using Logos scintillators with a CCD camera and the result data were from 2.33 mm to for 77 MeV to 9.70 mm for 220 MeV. In different field sizes, a comparison between the dose measured using PTW Semiflex and the AcurosPT estimated dose were performed to study the halo effect. All the measured dosimetric parameters showed that the design specifications were well achieved, and the results are suitable for being used as a part of the clinical commissioning and quality assurance program for treating patients.
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Date Issued: 2021
PURL: http://purl.flvc.org/fau/fd/FA00013691
Subject Headings: Proton Therapy, Dosimetry
Format: Document (PDF)

Title: Development of an Innovative Daily QA System for Pencil-Beam Scanning Proton Therapy.
Creator: Kassel, Maxwell, Shang, Charles, Muhammad, Wazir, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: In this work, we have developed a robust daily quality assurance (QA) system for pencil-beam scanning (PBS) dosimetry. A novel phantom and multi-PTV PBS plan were used in conjunction with the Sun Nuclear Daily QA3 multichamber detector array to verify output, range, and spot position. The sensitivity to detect change in these parameters with our designed tests was determined empirically. Associated tolerance levels were established based on these sensitivities and guidelines published in...
Show moreIn this work, we have developed a robust daily quality assurance (QA) system for pencil-beam scanning (PBS) dosimetry. A novel phantom and multi-PTV PBS plan were used in conjunction with the Sun Nuclear Daily QA3 multichamber detector array to verify output, range, and spot position. The sensitivity to detect change in these parameters with our designed tests was determined empirically. Associated tolerance levels were established based on these sensitivities and guidelines published in recent American Association of Physics in Medicine (AAPM) task group reports. The output has remained within the 3% tolerance and the range was within ±1mm. Spot position has remained within ±2mm. This daily QA procedure is quick and efficient with the time required for setup and delivery at less than 10 minutes.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013623
Subject Headings: Proton Therapy, Radiation dosimetry, Quality assurance
Format: Document (PDF)

Title: A MONTE CARLO STUDY OF THE NEUTRON AMBIENT DOSE EQUIVALENT FROM A PROTON PENCIL BEAM MEDICAL THERAPY UNIT.
Creator: Llanes, Alejandro Rene Lopez, Muhammad, Wazir, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: Proton Therapy, an effective cancer treatment, poses unintended consequences for patients and personnel due to secondary neutron production. This study investigates neutron attenuation in shielding materials like concrete using Monte Carlo (MC) simulations to optimize shielding requirements. Experimental limitations, such as detector sensitivity, energy range response, and spatial resolution, lead to inaccurate evaluations. MC simulations address that by modeling radiation transport and...
Show moreProton Therapy, an effective cancer treatment, poses unintended consequences for patients and personnel due to secondary neutron production. This study investigates neutron attenuation in shielding materials like concrete using Monte Carlo (MC) simulations to optimize shielding requirements. Experimental limitations, such as detector sensitivity, energy range response, and spatial resolution, lead to inaccurate evaluations. MC simulations address that by modeling radiation transport and neutron interactions with shielding materials. The TOPAS-MC code simulated secondary neutrons generated by a 226.5 MeV energy proton beam on a 30 cm diameter tissue-equivalent target. The target was placed in a 200 cm spherical concrete shell with a 100 cm inner radius and 2.3 g/cm3 density. Energy deposition and particle fluence were scored in 20 radial points across 18 angular positions, and the mean value per particle was estimated. Neutron fluence to ambient dose equivalent conversion coefficients from ICRU Report No. 95 were used to calculate the total dose equivalent values, which were scaled based on distance and concrete shield thickness.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014213
Subject Headings: Proton Therapy, Monte Carlo simulation, Neutrons
Format: Document (PDF)

Title: Development of a Monte Carlo Simulation Model for Varian ProBeam Compact Single-Room Proton Therapy System using GEANT4.
Creator: String, Shawn, Muhammad, Wazir, Shang, Charles, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: Proton therapy with pencil beam scanning technique is a novel technique to treat cancer patients due to its unique biophysical properties. However, a small error in dose calculation may lead towards undesired greater uncertainties in planed doses. This project aims to create a simulation model of Varian ProBeam Compact using the GEANT4 Monte Carlo simulation tool kit. Experimental data from the first clinical ProBeam Compact system at South Florida Proton Therapy Institute was used to...
Show moreProton therapy with pencil beam scanning technique is a novel technique to treat cancer patients due to its unique biophysical properties. However, a small error in dose calculation may lead towards undesired greater uncertainties in planed doses. This project aims to create a simulation model of Varian ProBeam Compact using the GEANT4 Monte Carlo simulation tool kit. Experimental data from the first clinical ProBeam Compact system at South Florida Proton Therapy Institute was used to validate the simulation model. A comparison was made between the experimental and simulated Integrated Depth-Dose curves using a 2%/2mm gamma index test with 100% of points passing. The beam spot standard deviation sizes (s!) were compared using percent deviation. All simulated s! matched the experimental s! within 2.5%, except 70 and 80 MeV. The model can be used to develop a more comprehensive model as an independent dose verification tool and further investigate dose distribution.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013547
Subject Headings: Proton Therapy, Monte-Carlo-Simulation, Radiotherapy Dosage
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.
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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: 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.
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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: NON-RADIOACTIVE ELEMENTS FOR PROMPT GAMMA ENHANCEMENT IN PROTON THERAPY.
Creator: Galanakou, Panagiota, Muhammad, Wazir, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: Intensity modulated proton beam scanning therapy allows for highly conformal dose distribution and better sparing of organ-at-risk compared to conventional photon radiotherapy, thanks to the characteristic dose deposition at depth, the Bragg Peak (BP), of protons as a function of depth and energy. However, proton range uncertainties lead to extended clinical margins, at the expense of treatment quality. Prompt Gamma (PG) rays emitted during non- elastic interactions of proton with the matter...
Show moreIntensity modulated proton beam scanning therapy allows for highly conformal dose distribution and better sparing of organ-at-risk compared to conventional photon radiotherapy, thanks to the characteristic dose deposition at depth, the Bragg Peak (BP), of protons as a function of depth and energy. However, proton range uncertainties lead to extended clinical margins, at the expense of treatment quality. Prompt Gamma (PG) rays emitted during non- elastic interactions of proton with the matter have been proposed for in-vivo proton range tracking. Nevertheless, poor PG statistics downgrade the potential of the clinical implementation of the proposed techniques. We study the insertion of the nonradioactive elements 19F, 17O, 127I in a tumor area to enhance the PG production of 4.44 MeV (P1) and 6.15 MeV (P2) PG rays emitted during proton irradiation, both correlated with the distal fall-off of the BP. We developed a novel Monte Carlo (MC) model using the TOPAS MC package. With this model, we simulated incident proton beams with energies of 75 MeV, 100 MeV and 200 MeV in co-centric cylindrical phantoms. The outer cylinder (scorer) was filled with water and the inner cylinder (simulating a tumor region inside water-equivalent body) was filled with water containing 0.1%–20% weight fractions of each of the tested elements.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014222
Subject Headings: Proton Therapy, Monte Carlo method--Simulation, Gamma rays
Format: Document (PDF)

Title: Exploring appropriate offset values for pencil beam and Monte Carlo dose optimization in lung stereotactic body radiotherapy encompassing the effects of respiration and tumor location.
Creator: Evans, Grant, Shang, Charles, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Evaluation of dose optimization using the Pencil Beam (PB) and Monte Carlo (MC) algorithms may allow physicists to apply dosimetric offsets to account for inaccuracies of the PB algorithm for lung cancer treatment with Stereotactic Body Radiotherapy (SBRT). 20 cases of Non-Small Cell Lung Cancer (NSCLC) were selected. Treatment plans were created with Brainlab iPlanDose® 4.1.2. The D97 of the Planning Target Volume (PTV) was normalized to 50 Gy on the Average Intensity Projection (AIP) using...
Show moreEvaluation of dose optimization using the Pencil Beam (PB) and Monte Carlo (MC) algorithms may allow physicists to apply dosimetric offsets to account for inaccuracies of the PB algorithm for lung cancer treatment with Stereotactic Body Radiotherapy (SBRT). 20 cases of Non-Small Cell Lung Cancer (NSCLC) were selected. Treatment plans were created with Brainlab iPlanDose® 4.1.2. The D97 of the Planning Target Volume (PTV) was normalized to 50 Gy on the Average Intensity Projection (AIP) using the fast PB and compared with MC. This exact plan with the same beam Monitor Units (MUs) was recalculated over each respiratory phase. The results show that the PB algorithm has a 2.3-2.4% less overestimation at the maximum exhalation phase than the maximum inhalation phase when compared to MC. Significantly smaller dose difference between PB and MC is also shown in plans for peripheral lesions (7.7 ± 0.7%) versus central lesions (12.7±0.8%)(p< 0.01).
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004105, http://purl.flvc.org/fau/fd/FA00004105
Subject Headings: Drug development -- Computer simulation, Image guided radiation therapy, Lung cancer -- Treatment, Monte Carlo method, Proton beams, Transport theory
Format: Document (PDF)

Title: A dosimetric study of a heterogeneous phantom for lung stereotactic body radiation therapy comparing Monte Carlo and pencil beam calculations to dose distributions measured with a 2-d diode array.
Creator: Curley, Casey Michael, Ouhib, Zoubir, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Monte Carlo (MC) and Pencil Beam (PB) calculations are compared to their measured planar dose distributions using a 2-D diode array for lung Stereotactic Body Radiation Therapy (SBRT). The planar dose distributions were studied for two different phantom types: an in-house heterogeneous phantom and a homogeneous phantom. The motivation is to mimic the human anatomy during a lung SBRT treatment and incorporate heterogeneities into the pre-treatment Quality Assurance process, where measured and...
Show moreMonte Carlo (MC) and Pencil Beam (PB) calculations are compared to their measured planar dose distributions using a 2-D diode array for lung Stereotactic Body Radiation Therapy (SBRT). The planar dose distributions were studied for two different phantom types: an in-house heterogeneous phantom and a homogeneous phantom. The motivation is to mimic the human anatomy during a lung SBRT treatment and incorporate heterogeneities into the pre-treatment Quality Assurance process, where measured and calculated planar dose distributions are compared before the radiation treatment. Individual and combined field dosimetry has been performed for both fixed gantry angle (anterior to posterior) and planned gantry angle delivery. A gamma analysis has been performed for all beam arrangements. The measurements were obtained using the 2-D diode array MapCHECK 2™.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004360
Subject Headings: Cancer -- Radiotherapy, Drug development -- Computer simulation, Image guided radiation therapy, Ion bombardment, Lung cancer -- Treatment, Medical physics, Monte Carlo method, Proton beams
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.
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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)

Proton Therapy (8)	+ -
Proton beams (3)	+ -
Drug development -- Computer simulation (2)	+ -
Image guided radiation therapy (2)	+ -
Lung cancer -- Treatment (2)	+ -

Monte Carlo method (2)	+ -
Calibration (1)	+ -
Cancer -- Radiotherapy (1)	+ -
Cancer--Radiotherapy. (1)	+ -
Dosimetry (1)	+ -
Gamma rays (1)	+ -
Image-guided radiation therapy. (1)	+ -
Ion bombardment (1)	+ -
Ion bombardment. (1)	+ -
Lungs--Cancer--Treatment. (1)	+ -
Medical physics (1)	+ -
Medical physics. (1)	+ -
Monte Carlo method--Simulation (1)	+ -
Monte Carlo method. (1)	+ -
Monte Carlo simulation (1)	+ -
Monte-Carlo-Simulation (1)	+ -
Neutrons (1)	+ -
Proton beams. (1)	+ -
Quality assurance (1)	+ -
Radiation dosimetry (1)	+ -
Radiotherapy (1)	+ -
Radiotherapy Dosage (1)	+ -
Radiotherapy Planning, Computer-Assisted (1)	+ -
Radiotherapy--Measurement (1)	+ -
Tomography (1)	+ -

Charles E. Schmidt College of Science (11)	+ -
Department of Physics (11)	+ -
Florida Atlantic University (11)	+ -
Muhammad, Wazir (6)	+ -
Shang, Charles (6)	+ -

Leventouri, Theodora (3)	+ -
Curley, Casey Michael (2)	+ -
Ouhib, Zoubir (2)	+ -
Beqiri, Atdhe (1)	+ -
Evans, Grant (1)	+ -
Fathallah, Shreen Mohamed (1)	+ -
Galanakou, Panagiota (1)	+ -
Ghasemi Ghonchehnazi, Maryam (1)	+ -
Kassel, Maxwell (1)	+ -
Leyva, Michael (1)	+ -
Llanes, Alejandro Rene Lopez (1)	+ -
String, Shawn (1)	+ -

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