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Article: Spatial Mesh-Based Surface Source Model for the Electron Contamination of an 18 MV Photon Beams.

Ezzati, Ahad Ollah / Studenski, Matthew T / Gohari, Masuomeh

2021 Volume 45, Issue 4, Page(s) 221–225

Abstract: Background: Source modeling is an approach to reduce computational burden in Monte Carlo simulations but at the cost of reduced accuracy. Although this method can be effective, one component of the source model that is exceptionally difficult to model ... ...

Abstract	Background: Source modeling is an approach to reduce computational burden in Monte Carlo simulations but at the cost of reduced accuracy. Although this method can be effective, one component of the source model that is exceptionally difficult to model is the electron contamination, a significant contributor to the skin and shallow dose. Aims and objectives: To improve the accuracy for the electron contamination component of the overall source model, we have generated a spatial mesh based surface source model. Methods and materials: The source model is located downstream from the flattening filter and mirror but upstream from the movable jaws. A typical phase space file uses around ten parameters per particle, but this method simplifies this number to five components. By using only the electron distance from the central axis, angles from the central axis and energy, the computational time and disk space required is greatly reduced. Results and conclusion: Despite the simplification in the source model, the electron contamination is still accurate to within 1.5%.
Language	English
Publishing date	2021-02-02
Publishing country	India
Document type	Journal Article
ZDB-ID	1193902-3
ISSN	1998-3913 ; 0971-6203
ISSN (online)	1998-3913
ISSN	0971-6203
DOI	10.4103/jmp.JMP_29_20
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Article ; Online: Improving TBI lung dose calculations: Can the treatment planning system help?

Lamichhane, Narottam / Studenski, Matthew T

Medical dosimetry : official journal of the American Association of Medical Dosimetrists

2019 Volume 45, Issue 2, Page(s) 168–171

Abstract: Lung toxicity is a serious concern during total body irradiation (TBI). Therefore, evaluation of accurate dose calculation when using lung blocks is of utmost importance. Existing clinical treatment planning systems can perform the calculation but there ... ...

Abstract	Lung toxicity is a serious concern during total body irradiation (TBI). Therefore, evaluation of accurate dose calculation when using lung blocks is of utmost importance. Existing clinical treatment planning systems can perform the calculation but there are large inaccuracies when calculating volumetric dose at extended distances in the presence of high atomic number materials. Percent depth dose and absolute dose measurements acquired at 400 cm SSD with a cerrobend block were compared with calculated values from the Eclipse treatment planning system using AAA and Acuros. The block was simulated in 2 ways; (1) manually drawing a contour to mimic the block and (2) creating a virtual block in the accessory tray. Although the relative dose distribution was accurately calculated, larger deviations of around 50% and 40% were observed between measured depth dose and absolute dose with AAA and Acuros, respectively. Deviations were reduced by optimizing the relative electron density in the contoured block or the transmission factor in the virtual block.
MeSH term(s)	Humans ; Lung Injury/etiology ; Radiotherapy Planning, Computer-Assisted ; Whole-Body Irradiation/adverse effects
Language	English
Publishing date	2019-11-12
Publishing country	United States
Document type	Journal Article
ZDB-ID	645065-9
ISSN	1873-4022 ; 0958-3947 ; 0739-0211
ISSN (online)	1873-4022
ISSN	0958-3947 ; 0739-0211
DOI	10.1016/j.meddos.2019.09.004
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Article ; Online: Increasing the efficiency of cone-beam CT based delta-radiomics using automated contours to predict radiotherapy-related toxicities in prostate cancer.

Delgadillo, Rodrigo / Deana, Anthony M / Ford, John C / Studenski, Matthew T / Padgett, Kyle R / Abramowitz, Matthew C / Pra, Alan Dal / Spieler, Benjamin O / Dogan, Nesrin

Scientific reports

2024 Volume 14, Issue 1, Page(s) 9563

Abstract: Extracting longitudinal image quantitative data, known as delta-radiomics, has the potential to capture changes in a patient's anatomy throughout the course of radiation treatment for prostate cancer. Some of the major challenges of delta-radiomics ... ...

Abstract	Extracting longitudinal image quantitative data, known as delta-radiomics, has the potential to capture changes in a patient's anatomy throughout the course of radiation treatment for prostate cancer. Some of the major challenges of delta-radiomics studies are contouring the structures for individual fractions and accruing patients' data in an efficient manner. The manual contouring process is often time consuming and would limit the efficiency of accruing larger sample sizes for future studies. The problem is amplified because the contours are often made by highly trained radiation oncologists with limited time to dedicate to research studies of this nature. This work compares the use of automated prostate contours generated using a deformable image-based algorithm to make predictive models of genitourinary and changes in total international prostate symptom score in comparison to manually contours for a cohort of fifty patients. Area under the curve of manual and automated models were compared using the Delong test. This study demonstrated that the delta-radiomics models were similar for both automated and manual delta-radiomics models.
MeSH term(s)	Humans ; Male ; Prostatic Neoplasms/radiotherapy ; Prostatic Neoplasms/diagnostic imaging ; Cone-Beam Computed Tomography/methods ; Algorithms ; Aged ; Middle Aged ; Radiation Injuries/etiology ; Radiomics
Language	English
Publishing date	2024-04-26
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-024-60281-6
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Article ; Online: Expanding the reach of medical physics: Immunotherapy should be included as part of the curriculum for medical physics education and training.

Lamichhane, Narottam / Studenski, Matthew T / Rong, Yi

Journal of applied clinical medical physics

2019 Volume 21, Issue 1, Page(s) 6–10

MeSH term(s)	Curriculum/standards ; Education, Medical/standards ; Health Physics/education ; Humans ; Immunotherapy
Language	English
Publishing date	2019-12-20
Publishing country	United States
Document type	Editorial
ZDB-ID	2010347-5
ISSN	1526-9914 ; 1526-9914
ISSN (online)	1526-9914
ISSN	1526-9914
DOI	10.1002/acm2.12796
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Article ; Online: Effective dose to patients and staff when using a mobile PET/SPECT system.

Studenski, Matthew T

Journal of applied clinical medical physics

2013 Volume 14, Issue 3, Page(s) 4250

Abstract: The purpose of this study was to determine the number of weekly acquisitions permissible using a mobile PET/SPECT scanner for myocardial perfusion/viability imaging in an intensive care unit (ICU) based on the effective dose to patients and staff. The ... ...

Abstract	The purpose of this study was to determine the number of weekly acquisitions permissible using a mobile PET/SPECT scanner for myocardial perfusion/viability imaging in an intensive care unit (ICU) based on the effective dose to patients and staff. The effective dose to other patients and staff in an ICU was calculated following recommendations from the American Association of Physicists in Medicine Task Group 108 report (AAPM TG-108). The number of weekly acquisitions using 555 MBq (15 mCi) Tc-99m for myocardial perfusion or F-18 for myocardial viability was determined using the regulatory limits described in the Code of Federal Regulations 10 CFR 20. To increase the number of weekly acquisitions allowed, a reduction in administered dose and portable shielding was considered. A single myocardial perfusion image can be acquired with Tc-99m each week with a dose reduction to 455 MBq (12.3 mCi) without additional shielding. To acquire a myocardial viability image with F-18, an activity reduction to 220 MBq (5.9 mCi) is required to meet the regulatory effective dose limit without additional shielding. More than one weekly acquisition can be performed if additional shielding or activity reduction is utilized. A method for calculating dose to patients and staff in an ICU has been developed using conservative assumptions and following AAPM TG-108. This calculation must be repeated for each individual clinic before any acquisition is performed.
MeSH term(s)	Feasibility Studies ; Humans ; Intensive Care Units ; Mobile Health Units/statistics & numerical data ; Myocardial Perfusion Imaging/adverse effects ; Personnel, Hospital/standards ; Positron-Emission Tomography/adverse effects ; Radiation Dosage ; Radiation Protection ; Radiopharmaceuticals ; Technetium Tc 99m Sestamibi ; Tomography, Emission-Computed, Single-Photon/adverse effects
Chemical Substances	Radiopharmaceuticals ; Technetium Tc 99m Sestamibi (971Z4W1S09)
Language	English
Publishing date	2013-05-06
Publishing country	United States
Document type	Journal Article
ZDB-ID	2010347-5
ISSN	1526-9914 ; 1526-9914
ISSN (online)	1526-9914
ISSN	1526-9914
DOI	10.1120/jacmp.v14i3.4250
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Article ; Online: Cone beam CT-based adaptive intensity modulated proton therapy assessment using automated planning for head-and-neck cancer.

Xu, Yihang / Jin, William / Butkus, Michael / De Ornelas, Mariluz / Cyriac, Jonathan / Studenski, Matthew T / Padgett, Kyle / Simpson, Garrett / Samuels, Stuart / Samuels, Michael / Dogan, Nesrin

Radiation oncology (London, England)

2024 Volume 19, Issue 1, Page(s) 13

Abstract: Background: To assess the feasibility of CBCT-based adaptive intensity modulated proton therapy (IMPT) using automated planning for treatment of head and neck (HN) cancers.: Methods: Twenty HN cancer patients who received radiotherapy and had ... ...

Abstract	Background: To assess the feasibility of CBCT-based adaptive intensity modulated proton therapy (IMPT) using automated planning for treatment of head and neck (HN) cancers. Methods: Twenty HN cancer patients who received radiotherapy and had pretreatment CBCTs were included in this study. Initial IMPT plans were created using automated planning software for all patients. Synthetic CTs (sCT) were then created by deforming the planning CT (pCT) to the pretreatment CBCTs. To assess dose calculation accuracy on sCTs, repeat CTs (rCTs) were deformed to the pretreatment CBCT obtained on the same day to create deformed rCT (rCT Results: Gamma analysis of the dose recalculated on sCT and rCT Conclusion: sCTs can be a useful tool for accurate proton dose calculation. Adaptive IMPT resulted in better CTV coverage, OAR sparing and lower NTCP for some OARs as compared with non-adaptive IMPT.
MeSH term(s)	Humans ; Proton Therapy ; Radiotherapy, Intensity-Modulated ; Protons ; Cone-Beam Computed Tomography ; Head and Neck Neoplasms ; Blood Coagulation Disorders
Chemical Substances	Protons
Language	English
Publishing date	2024-01-23
Publishing country	England
Document type	Journal Article
ZDB-ID	2224965-5
ISSN	1748-717X ; 1748-717X
ISSN (online)	1748-717X
ISSN	1748-717X
DOI	10.1186/s13014-024-02406-9
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Article ; Online: Neutron damage induced in cardiovascular implantable electronic devices from a clinical 18 MV photon beam: A Monte Carlo study.

Ezzati, Ahad Ollah / Studenski, Matthew T

Medical physics

2017 Volume 44, Issue 11, Page(s) 5660–5666

Abstract: Purpose: The purpose of this study was to quantify the relative neutron damage induced in CIEDs from clinical 18 MV photon beams for varying field sizes, depths, and off axis distances.: Methods and materials: Damage was assessed using silicon damage ...

Abstract	Purpose: The purpose of this study was to quantify the relative neutron damage induced in CIEDs from clinical 18 MV photon beams for varying field sizes, depths, and off axis distances. Methods and materials: Damage was assessed using silicon damage response functions and ICRP neutron dose conversion factors in MCNPX. Particular attention was devoted to the modelling of the Varian 2100C/D linear accelerator to ensure accurate contamination neutron spectra. Neutron dose, fluence and relative damage to CIEDs was calculated. Results: CIED damage from neutrons is related to the neutron dose rather than the neutron fluence. As field size increases, the region of high damage probability extends to a greater distance beyond the edge of the field than with smaller fields. At a distance greater than 50 cm or from the central axis or a depth deeper than 10 cm, the probability of damage is less than 10% of the central axis damage probability for all field sizes. Conclusions: Clinically, increasing the depth or the distance from the central axis to the CIED will reduce the probability of damage from neutrons. Care must be taken when treating large fields as the overall probability of damage increase as does the distance the higher probability of damage extends beyond the field edge.
MeSH term(s)	Cardiovascular System ; Monte Carlo Method ; Neutrons/adverse effects ; Particle Accelerators ; Photons/adverse effects ; Photons/therapeutic use ; Prostheses and Implants ; Radiation Dosage
Language	English
Publishing date	2017-11
Publishing country	United States
Document type	Journal Article
ZDB-ID	188780-4
ISSN	2473-4209 ; 0094-2405
ISSN (online)	2473-4209
ISSN	0094-2405
DOI	10.1002/mp.12581
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Article: Lung shunt fraction calculation using

Georgiou, Mike F / Kuker, Russ A / Studenski, Matthew T / Ahlman, Preeti P / Witte, Megan / Portelance, Lorraine

EJNMMI research

2021 Volume 11, Issue 1, Page(s) 96

Abstract: Background: 99m: Results: LSF calculation was obtained using two different methodologies in 85 cases from consecutive patients intended to receive : Conclusions: This study demonstrates that LSF calculation using planar imaging can be ... ...

Abstract	Background: 99m Results: LSF calculation was obtained using two different methodologies in 85 cases from consecutive patients intended to receive Conclusions: This study demonstrates that LSF calculation using planar imaging can be significantly overestimated while calculation using SPECT/CT imaging and appropriate segmentation tools can be more accurate. Minimizing the errors in obtaining the LSF can lead to more effective
Language	English
Publishing date	2021-09-28
Publishing country	Germany
Document type	Journal Article
ZDB-ID	2619892-7
ISSN	2191-219X
ISSN	2191-219X
DOI	10.1186/s13550-021-00837-z
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Article ; Online: Comprehensive assessment of the effect of eye plaque tilt on tumor dosimetry.

Studenski, Matthew T / Markoe, Arnold / Samuels, Stuart E / Correa, Zelia M / Bossart, Elizabeth / Harbour, J William

Brachytherapy

2021 Volume 20, Issue 6, Page(s) 1289–1295

Abstract: Purpose: Tilting of the posterior plaque margin during eye plaque brachytherapy can lead to tumor underdosing and increased risk of local recurrence. We performed a quantitative analysis of the dosimetric effects of plaque tilt as a function of tumor ... ...

Abstract	Purpose: Tilting of the posterior plaque margin during eye plaque brachytherapy can lead to tumor underdosing and increased risk of local recurrence. We performed a quantitative analysis of the dosimetric effects of plaque tilt as a function of tumor position, basal dimension, height and plaque type using 3D treatment planning software. Materials and methods: Posterior and anterior tumors with largest basal dimensions of 6, 12 and 18 mm and heights of 4, 7 and 10 mm were modeled. Both Eye Physics and COMS plaques were simulated and uniformly loaded. Plans were normalized to 85 Gy at the tumor apex. Posterior plaque tilts of 1, 2, 3 and 4 mm were simulated. Results: Volumetric coverage is more sensitive to tilt than the area coverage. Wide, flat tumors are more susceptible to tilt. Apical dose changed significantly as a function of tumor height and diameter. No other parameter exhibited significant differences. Posterior tumors are slightly more susceptible to tilt due to the use of notched plaques. Plaque type does not significantly alter the effect of plaque tilt. Conclusions: Wide, flat tumors are the most susceptible to plaque tilt. Tumor location or plaque type does not have a significant effect on dosimetry changes from plaque tilt. Robust clinical procedures such as the use of mattress sutures, pre- and post-implant ultrasound and post-implant dosimetry can all mitigate the risk associated with plaque tilt.
MeSH term(s)	Brachytherapy/methods ; Eye Neoplasms ; Humans ; Melanoma ; Radiometry ; Radiotherapy Dosage
Language	English
Publishing date	2021-06-28
Publishing country	United States
Document type	Journal Article
ZDB-ID	2098608-7
ISSN	1873-1449 ; 1538-4721
ISSN (online)	1873-1449
ISSN	1538-4721
DOI	10.1016/j.brachy.2021.05.013
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Article ; Online: CivaSheet® use for soft tissue sarcoma: A single institution experience.

Seldon, Crystal / Grossman, Julie G / Shrivastava, Gautam / Fernandez, Melanie / Jin, William / Conaway, Sheila / Rosenberg, Andrew / Livingstone, Alan / Franceschi, Dido / Jonczak, Emily / Trent, Jonathan / Subhawong, Ty / Studenski, Matthew T / Yechieli, Raphael

Brachytherapy

2023 Volume 22, Issue 5, Page(s) 649–654

Abstract: Objective: CivaSheet is a palladium-103, implantable, intraoperative radiation therapy device which emits unidirectional radiation that enables boost doses in patients who have otherwise received the maximum radiation dose. Here, we present our initial ... ...

Abstract	Objective: CivaSheet is a palladium-103, implantable, intraoperative radiation therapy device which emits unidirectional radiation that enables boost doses in patients who have otherwise received the maximum radiation dose. Here, we present our initial clinical experience with the first 10 cases using this new technology. Methods and materials: A retrospective chart review of all patients with STS treated with surgical resection and CivaSheet placement at the University of Miami Hospital, a tertiary care center, from January 2018 to December 2019, was performed. Adjuvant radiation was administered by a palladium-103 implant, which delivered an average of 47 Gy (35-55) to a depth of 5 mm. Results: Nine patients underwent CivaSheet placement from January 2018 until December 2019 for a total of 10 CivaSheets placed (1 patient had 2 CivaSheets inserted) and followed for a mean of 27 months (4-45 months). Four tumors were located in the retroperitoneum, two in the chest, two in the groin, and two within the lower extremity. At the time of tumor resection and CivaSheet placement, tumor sizes ranged from 2.5 cm to 13.8 cm with an average of 7.6 cm. Four patients necessitated musculocutaneous tissue flaps for closure and reconstruction. All patients with Grade 4 complications had flap reconstruction and prior radiation. Four patients' tumors recurred locally for a local recurrence rate of 40%. Three patients had modified accordion Grade 4 complications necessitating additional surgery for CivaSheet removal. Extremity tumors unanimously developed modified accordion Grade 4 adverse events. Conclusions: CivaSheet may be an acceptable alternative treatment modality compared to prior brachytherapy methods.
MeSH term(s)	Humans ; Brachytherapy/methods ; Retrospective Studies ; Radioisotopes/therapeutic use ; Sarcoma/radiotherapy ; Sarcoma/surgery ; Sarcoma/pathology ; Soft Tissue Neoplasms/radiotherapy
Chemical Substances	Palladium-103 (68QTV136DF) ; Radioisotopes
Language	English
Publishing date	2023-06-02
Publishing country	United States
Document type	Journal Article
ZDB-ID	2098608-7
ISSN	1873-1449 ; 1538-4721
ISSN (online)	1873-1449
ISSN	1538-4721
DOI	10.1016/j.brachy.2023.03.001
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