1
|
Sabouri P, Molitoris J, Ranjbar M, Moreau J, Simone CB, Mohindra P, Langen K, Mossahebi S. Dosimetric Evaluation and Reproducibility of Breath-hold Plans in Intensity Modulated Proton Therapy: An Initial Clinical Experience. Adv Radiat Oncol 2024; 9:101392. [PMID: 38292885 PMCID: PMC10826160 DOI: 10.1016/j.adro.2023.101392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 10/05/2023] [Indexed: 02/01/2024] Open
Abstract
Purpose Breath-hold (BH) technique can mitigate target motion, minimize target margins, reduce normal tissue doses, and lower the effect of interplay effects with intensity-modulated proton therapy (IMPT). This study presents dosimetric comparisons between BH and nonbreath-hold (non-BH) IMPT plans and investigates the reproducibility of BH plans using frequent quality assurance (QA) computed tomography scans (CT). Methods and Materials Data from 77 consecutive patients with liver (n = 32), mediastinal/lung (n = 21), nonliver upper abdomen (n = 20), and malignancies in the gastroesophageal junction (n = 4), that were treated with a BH spirometry system (SDX) were evaluated. All patients underwent both BH CT and 4-dimensional CT simulations. Clinically acceptable BH and non-BH plans were generated on each scan, and dose-volume histograms of the 2 plans were compared. Reproducibility of the BH plans for 30 consecutive patients was assessed using 1 to 3 QA CTs per patient and variations in dose-volume histograms for deformed target and organs at risk (OARs) volumes were compared with the initial CT plan. Results Use of BH scans reduced initial and boost target volumes to 72% ± 20% and 70% ± 17% of non-BH volumes, respectively. Additionally, mean dose to liver, stomach, kidney, esophagus, heart, and lung V20 were each reduced to 71% to 79% with the BH technique. Similarly, small and large bowels, heart, and spinal cord maximum doses were each lowered to 68% to 84%. Analysis of 62 QA CT scans demonstrated that mean target and OAR doses using BH scans were reproducible to within 5% of their nominal plan values. Conclusions The BH technique reduces the irradiated volume, leading to clinically significant reductions in OAR doses. By mitigating tumor motion, the BH technique leads to reproducible target coverage and OAR doses. Its use can reduce motion-related uncertainties that are normally associated with the treatment of thoracic and abdominal tumors and, therefore, optimize IMPT delivery.
Collapse
Affiliation(s)
- Pouya Sabouri
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Jason Molitoris
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland
- Maryland Proton Treatment Center, Baltimore, Maryland
| | - Maida Ranjbar
- Department of Radiation Oncology, University of California San Diego, La Jolla, California
| | | | | | - Pranshu Mohindra
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland
- Maryland Proton Treatment Center, Baltimore, Maryland
| | - Katja Langen
- Department of Radiation Oncology, Emory University, Atlanta, Georgia
| | - Sina Mossahebi
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland
- Maryland Proton Treatment Center, Baltimore, Maryland
| |
Collapse
|
2
|
Zhu M, Flampouri S, Stanforth A, Slopsema R, Diamond Z, LePain W, Langen K. Effect of the initial energy layer and spot placement parameters on IMPT delivery efficiency and plan quality. J Appl Clin Med Phys 2023; 24:e13997. [PMID: 37101399 PMCID: PMC10476974 DOI: 10.1002/acm2.13997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 03/14/2023] [Accepted: 04/05/2023] [Indexed: 04/28/2023] Open
Abstract
PURPOSE Improving efficiency of intensity modulated proton therapy (IMPT) treatment can be achieved by shortening the beam delivery time. The purpose of this study is to reduce the delivery time of IMPT, while maintaining the plan quality, by finding the optimal initial proton spot placement parameters. METHODS Seven patients previously treated in the thorax and abdomen with gated IMPT and voluntary breath-hold were included. In the clinical plans, the energy layer spacing (ELS) and spot spacing (SS) were set to 0.6-0.8 (as a scale factor of the default values). For each clinical plan, we created four plans with ELS increased to 1.0, 1.2, 1.4, and SS to 1.0 while keeping all other parameters unchanged. All 35 plans (130 fields) were delivered on a clinical proton machine and the beam delivery time was recorded for each field. RESULTS Increasing ELS and SS did not cause target coverage reduction. Increasing ELS had no effect on critical organ-at-risk (OAR) doses or the integral dose, while increasing SS resulted in slightly higher integral and selected OAR doses. Beam-on times were 48.4 ± 9.2 (range: 34.1-66.7) seconds for the clinical plans. Time reductions were 9.2 ± 3.3 s (18.7 ± 5.8%), 11.6 ± 3.5 s (23.1 ± 5.9%), and 14.7 ± 3.9 s (28.9 ± 6.1%) when ELS was changed to 1.0, 1.2, and 1.4, respectively, corresponding to 0.76-0.80 s/layer. SS change had a minimal effect (1.1 ± 1.6 s, or 1.9 ± 2.9%) on the beam-on time. CONCLUSION Increasing the energy layers spacing can reduce the beam delivery time effectively without compromising IMPT plan quality; increasing the SS had no meaningful impact on beam delivery time and resulted in plan-quality degradation in some cases.
Collapse
Affiliation(s)
- Mingyao Zhu
- Department of Radiation OncologyEmory University School of MedicineAtlantaGeorgiaUSA
| | - Stella Flampouri
- Department of Radiation OncologyEmory University School of MedicineAtlantaGeorgiaUSA
| | - Alex Stanforth
- Mechanical Engineering, Nuclear Radiological Engineering & Medical PhysicsGeorgia Institute of TechnologyAtlantaGeorgiaUSA
- Emory HealthcareAtlantaGeorgiaUSA
| | - Roelf Slopsema
- Department of Radiation OncologyEmory University School of MedicineAtlantaGeorgiaUSA
| | - Zachary Diamond
- Mechanical Engineering, Nuclear Radiological Engineering & Medical PhysicsGeorgia Institute of TechnologyAtlantaGeorgiaUSA
- Emory HealthcareAtlantaGeorgiaUSA
| | - William LePain
- Mechanical Engineering, Nuclear Radiological Engineering & Medical PhysicsGeorgia Institute of TechnologyAtlantaGeorgiaUSA
- Emory HealthcareAtlantaGeorgiaUSA
| | - Katja Langen
- Department of Radiation OncologyEmory University School of MedicineAtlantaGeorgiaUSA
| |
Collapse
|
3
|
Charyyev S, Chang CW, Zhu M, Lin L, Langen K, Dhabaan A. Characterization of 250 MeV Protons from the Varian ProBeam PBS System for FLASH Radiation Therapy. Int J Part Ther 2023; 9:279-289. [PMID: 37169007 PMCID: PMC10166018 DOI: 10.14338/ijpt-22-00027.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 01/24/2023] [Indexed: 03/05/2023] Open
Abstract
Abstract
Shoot-through proton FLASH radiation therapy has been proposed where the highest energy is extracted from a cyclotron to maximize the dose rate (DR). Although our proton pencil beam scanning system can deliver 250 MeV (the highest energy), this energy is not used clinically, and as such, 250 MeV has yet to be characterized during clinical commissioning. We aim to characterize the 250-MeV proton beam from the Varian ProBeam system for FLASH and assess the usability of the clinical monitoring ionization chamber (MIC) for FLASH use.
We measured the following data for beam commissioning: integral depth dose curve, spot sigma, and absolute dose. To evaluate the MIC, we measured output as a function of beam current. To characterize a 250 MeV FLASH beam, we measured (1) the central axis DR as a function of current and spot spacing and arrangement, (2) for a fixed spot spacing, the maximum field size that achieves FLASH DR (ie, > 40 Gy/s), and (3) DR reproducibility. All FLASH DR measurements were performed using an ion chamber for the absolute dose, and irradiation times were obtained from log files. We verified dose measurements using EBT-XD films and irradiation times using a fast, pixelated spectral detector.
R90 and R80 from integral depth dose were 37.58 and 37.69 cm, and spot sigma at the isocenter were σx = 3.336 and σy = 3.332 mm, respectively. The absolute dose output was measured as 0.343 Gy*mm2/MU for the commissioning conditions. Output was stable for beam currents up to 15 nA and gradually increased to 12-fold for 115 nA. Dose and DR depended on beam current, spot spacing, and arrangement and could be reproduced with 6.4% and 4.2% variations, respectively.
Although FLASH was achieved and the largest field size that delivers FLASH DR was determined as 35 × 35 mm2, the current MIC has DR dependence, and users should measure dose and DR independently each time for their FLASH applications.
Collapse
Affiliation(s)
- Serdar Charyyev
- 1 Department of Radiation Oncology, Stanford University, Palo Alto, CA, USA
| | - Chih-Wei Chang
- 2 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Mingyao Zhu
- 2 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Liyong Lin
- 2 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Katja Langen
- 2 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Anees Dhabaan
- 2 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| |
Collapse
|
4
|
Kocher M, Jockwitz C, Lohmann P, Stoffels G, Filss C, Motthagy FM, Ruge MI, Weiss Lucas C, Goldbrunner R, Shah NJ, Fink GR, Galldiks N, Langen K, Caspers S. P01.01.A Lesion-Function Analysis from Multimodal Imaging and Normative Brain Atlases for Prediction of Cognitive Deficits in Glioma Patients. Neuro Oncol 2022. [DOI: 10.1093/neuonc/noac174.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Cognitive deficits are common in glioma patients following multimodality therapy, but the relative impact of different types and locations of treatment-related brain damage and recurrent tumors on cognition is not well understood.
Material and Methods
In 121 WHO Grade III/IV glioma patients, structural MRI, O-(2-[18F]fluoroethyl)-L-tyrosine FET-PET, and neuropsychological testing were performed at a median interval of 14 months (range, 1-214 months) after therapy initiation. Resection cavities, T1-enhancing lesions, T2/FLAIR hyperintensities, and FET-PET positive tumor sites were semiautomatically segmented and elastically registered to a normative, resting state (RS) fMRI-based functional cortical network atlas and to the JHU atlas of white matter (WM) tracts, and their influence on cognitive test scores relative to a cohort of matched healthy subjects was assessed.
Results
T2/FLAIR hyperintensities presumably caused by radiation therapy covered more extensive brain areas than the other lesion types and significantly impaired cognitive performance in many domains when affecting left-hemispheric RS-nodes and WM-tracts as opposed to brain tissue damage caused by resection or recurrent tumors. Verbal episodic memory proved to be especially vulnerable to T2/FLAIR abnormalities affecting the nodes and tracts of the left temporal lobe.
Conclusion
In order to improve radiotherapy planning, publicly available brain atlases, in conjunction with elastic registration techniques, should be used, similar to neuronavigation in neurosurgery.
Collapse
Affiliation(s)
- M Kocher
- University of Cologne , Cologne , Germany
- Research Center Juelich , Juelich , Germany
| | - C Jockwitz
- Research Center Juelich , Juelich , Germany
| | - P Lohmann
- Research Center Juelich , Juelich , Germany
| | - G Stoffels
- Research Center Juelich , Juelich , Germany
| | - C Filss
- Research Center Juelich , Juelich , Germany
| | - F M Motthagy
- Research Center Juelich , Juelich , Germany
- RWTH Aachen University , Aachen , Germany
| | - M I Ruge
- University of Cologne , Cologne , Germany
| | | | | | - N J Shah
- Research Center Juelich , Juelich , Germany
| | - G R Fink
- University of Cologne , Cologne , Germany
| | - N Galldiks
- University of Cologne , Cologne , Germany
| | - K Langen
- Research Center Juelich , Juelich , Germany
- RWTH Aachen University , Aachen , Germany
| | - S Caspers
- Research Center Juelich , Juelich , Germany
- University Duesseldorf , Duesseldorf , Germany
| |
Collapse
|
5
|
Kocher M, Jockwitz C, Lerche C, Sabel M, Lohmann P, Stoffels G, Filss C, Motthagy FM, Ruge MI, Fink GR, Shah NJ, Galldiks N, Caspers S, Langen K. P01.02.B Case Report: Disruption of Resting-State Networks and Cognitive Deficits After Whole Brain Irradiation for Singular Brain Metastasis. Neuro Oncol 2022. [DOI: 10.1093/neuonc/noac174.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Long-term survivors of whole brain radiation (WBRT) are at significant risk for developing cognitive deficits, but knowledge about the underlying pathophysiological mechanisms is limited. Therefore, we here report a rare case with a singular brain metastasis treated by resection and WBRT that survived for more than 10 years where we investigated the integrity of brain networks using resting-state functional MRI.
Material and Methods
A female patient with a left frontal non-small cell lung cancer (NSCLC) brain metastasis had resection and postoperative WBRT (30.0 in 3.0Gy fractions) and stayed free from brain metastasis recurrence for a follow-up period of 11 years. Structural magnetic resonance imaging (MRI) and amino acid [O-(2-[18F]fluoroethyl)-L-tyrosine] positron emission tomography (FET PET) were repeatedly acquired. At the last follow up, neurocognitive functions and resting-state functional connectivity (RSFC) using resting-state fMRI were assessed. Within-network and inter-network connectivity of seven resting-state networks were computed from a connectivity matrix. All measures were compared to a matched group of 10 female healthy subjects.
Results
At the 11-year follow-up, T2/FLAIR MR images of the patient showed extended regions of hyper-intensities covering mainly the white matter of the bilateral dorsal frontal and parietal lobes while sparing most of the temporal lobes. Compared to the healthy subjects, the patient performed significantly worse in all cognitive domains that included executive functions, attention and processing speed, while verbal working memory, verbal episodic memory, and visual working memory were left mostly unaffected. The connectivity matrix showed a heavily disturbed pattern with a widely distributed, scattered loss of RSFC. The within-network RSFC revealed a significant loss of connectivity within all seven networks where the dorsal attention and fronto-parietal
control networks were affected most severely. The inter-network RSFC was significantly reduced for the visual, somato-motor, and dorsal and ventral attention networks.
Conclusion
As demonstrated here in a patient with a metastatic NSCLC and long-term survival, WBRT may lead to extended white matter damage and cause severe disruption of the RSFC in multiple resting state networks. In consequence, executive functioning which is assumed to depend on the interaction of several networks may be severely impaired following WBRT apart from the well-recognized deficits in memory function.
Collapse
Affiliation(s)
- M Kocher
- University of Cologne , Cologne , Germany
- Research Center Juelich , Juelich , Germany
| | - C Jockwitz
- Research Center Juelich , Juelich , Germany
- University Duesseldorf , Duesseldorf , Germany
| | - C Lerche
- Research Center Juelich , Juelich , Germany
| | - M Sabel
- University Duesseldorf , Duesseldorf , Germany
| | - P Lohmann
- Research Center Juelich , Juelich , Germany
| | - G Stoffels
- Research Center Juelich , Juelich , Germany
| | - C Filss
- Research Center Juelich , Juelich , Germany
| | | | - M I Ruge
- University of Cologne , Cologne , Germany
| | - G R Fink
- University of Cologne , Cologne , Germany
| | - N J Shah
- Research Center Juelich , Juelich , Germany
| | - N Galldiks
- University of Cologne , Cologne , Germany
- Research Center Juelich , Juelich , Germany
| | - S Caspers
- Research Center Juelich , Juelich , Germany
- University Duesseldorf , Duesseldorf , Germany
| | - K Langen
- Research Center Juelich , Juelich , Germany
- RWTH Aachen University , Aachen , Germany
| |
Collapse
|
6
|
Ceccon GS, Werner J, Ruge MI, Goldbrunner R, Celik E, Baues C, Deckert M, Brunn A, Büttner R, Golla H, Nogova L, Schlamann M, Kabbasch C, Rueß D, Hampl J, Wollring M, Bauer EK, Tscherpel C, Fink GR, Langen K, Galldiks N. KS02.7.A Impact of FET PET on multidisciplinary neurooncological tumor board decisions in patients with brain tumors. Neuro Oncol 2022. [DOI: 10.1093/neuonc/noac174.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Following neurooncological treatment of brain tumors, neurooncologists are often confronted with equivocal MRI findings (e.g., treatment-related changes such as pseudoprogression, non-measurable contrast-enhancing lesions, T2/FLAIR signal alterations, pseudoresponse). Especially in Europe, amino-acid PET is increasingly integrated into multidisciplinary neurooncological tumor boards (MNTB) to overcome these diagnostic uncertainties. We evaluated the correctness of MNTB decisions, in which amino acid PET findings were taken into account.
Material and Methods
In a single-university center study, we retrospectively evaluated 182 MNTB decisions of 154 patients with histomolecularly defined WHO grade 3 or 4 gliomas (n=123), including glioblastoma (n=80), anaplastic glioma (n=42), and gliosarcoma (n=1), or brain metastases (n=31) secondary to lung cancer, melanoma, breast cancer, or colorectal cancer presenting equivocal MRI findings following anticancer treatment. All patients underwent O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET imaging as an adjunct for decision-making. Additionally, the patients’ clinical status, pretreatment, and conventional MRI findings were considered for decision-making. The presence of neoplastic tissue was considered if the mean FET uptake as assessed by tumor-to-brain ratios was > 2.0. MNTB decisions were validated using the neuropathological result in 42% (n=77) or clinicoradiologically in 58% (n=105). The diagnostic performance of MTNB decisions was evaluated using 2x2 contingency tables.
Results
The validation of all 182 MNTB recommendations, which integrated FET PET in the decision-making process, were correct in 95% (sensitivity, 97%; specificity, 75%; positive predictive value, 96%). Due to tumor progression, MNTB recommendations prompted a treatment change in 88% (n=160 of 182 decisions). When FET PET findings suggested progressive disease (n=157), MNTB decisions were correct in 96% (positive predictive value, 97%). In 22 MNTB decisions with the recommendation to continue the current treatment regimen, 82% were correctly identified as treatment-related changes.
Conclusion
FET PET seems to have a significant impact on MNTB decisions. A prospective evaluation of MNTB decisions with and without the integration of FET PET is warranted to define the added value of FET PET.
Collapse
Affiliation(s)
- G S Ceccon
- Department of Neurology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - J Werner
- Department of Neurology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - M I Ruge
- Department of Stereotactic and Functional Neurosurgery, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - R Goldbrunner
- Department of Neurosurgery, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - E Celik
- Department of Radiation Oncology and Cyberknife Center, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - C Baues
- Department of Radiation Oncology and Cyberknife Center, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - M Deckert
- Institute of Neuropathology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - A Brunn
- Institute of Neuropathology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - R Büttner
- Institute of Pathology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - H Golla
- Department of Palliative Medicine, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - L Nogova
- Department of Internal Medicine, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - M Schlamann
- Institute of Radiology, Division of Neuroradiology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - C Kabbasch
- Institute of Radiology, Division of Neuroradiology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - D Rueß
- Department of Stereotactic and Functional Neurosurgery, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - J Hampl
- Department of Neurosurgery, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - M Wollring
- Department of Neurology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich , Juelich , Germany
| | - E K Bauer
- Department of Neurology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
| | - C Tscherpel
- Department of Neurology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich , Juelich , Germany
| | - G R Fink
- Department of Neurology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich , Juelich , Germany
| | - K Langen
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich , Juelich , Germany
- Department of Nuclear Medicine, University Hospital RWTH Aachen , Aachen , Germany
| | - N Galldiks
- Department of Neurology, Faculty of Medicine and University Hospital Cologne , Cologne , Germany
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich , Juelich , Germany
| |
Collapse
|
7
|
Gao H, Liu J, Lin Y, Gan GN, Pratx G, Wang F, Langen K, Bradley JD, Rotondo RL, Li HH, Chen RC. Simultaneous dose and dose rate optimization (SDDRO) of the FLASH effect for pencil-beam-scanning proton therapy. Med Phys 2022; 49:2014-2025. [PMID: 34800301 PMCID: PMC8917068 DOI: 10.1002/mp.15356] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/29/2021] [Accepted: 10/25/2021] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Compared to CONV-RT (with conventional dose rate), FLASH-RT (with ultra-high dose rate) can provide biological dose sparing for organs-at-risk (OARs) via the so-called FLASH effect, in addition to physical dose sparing. However, the FLASH effect only occurs, when both dose and dose rate meet certain minimum thresholds. This work will develop a simultaneous dose and dose rate optimization (SDDRO) method accounting for both FLASH dose and dose rate constraints during treatment planning for pencil-beam-scanning proton therapy. METHODS SDDRO optimizes the FLASH effect (specific to FLASH-RT) as well as the dose distribution (similar to CONV-RT). The nonlinear dose rate constraint is linearized, and the reformulated optimization problem is efficiently solved via iterative convex relaxation powered by alternating direction method of multipliers. To resolve and quantify the generic tradeoff of FLASH-RT between FLASH and dose optimization, we propose the use of FLASH effective dose based on dose modifying factor (DMF) owing to the FLASH effect. RESULTS FLASH-RT via transmission beams (TB) (IMPT-TB or SDDRO) and CONV-RT via Bragg peaks (BP) (IMPT-BP) were evaluated for clinical prostate, lung, head-and-neck (HN), and brain cases. Despite the use of TB, which is generally suboptimal to BP for normal tissue sparing, FLASH-RT via SDDRO considerably reduced FLASH effective dose for high-dose OAR adjacent to the target. For example, in the lung SBRT case, the max esophageal dose constraint 27 Gy was only met by SDDRO (24.8 Gy), compared to IMPT-BP (35.3 Gy) or IMPT-TB (36.6 Gy); in the brain SRS case, the brain constraint V12Gy≤15cc was also only met by SDDRO (13.7cc), compared to IMPT-BP (43.9cc) or IMPT-TB (18.4cc). In addition, SDDRO substantially improved the FLASH coverage from IMPT-TB, e.g., an increase from 37.2% to 67.1% for lung, from 39.1% to 58.3% for prostate, from 65.4% to 82.1% for HN, from 50.8% to 73.3% for the brain. CONCLUSIONS Both FLASH dose and dose rate constraints are incorporated into SDDRO for FLASH-RT that jointly optimizes the FLASH effect and physical dose distribution. FLASH effective dose via FLASH DMF is introduced to reconcile the tradeoff between physical dose sparing and FLASH sparing, and quantify the net effective gain from CONV-RT to FLASH-RT.
Collapse
Affiliation(s)
- Hao Gao
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Jiulong Liu
- LSEC, Institute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, China
| | - Yuting Lin
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Gregory N Gan
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Guillem Pratx
- Department of Radiation Oncology, Stanford University, USA
| | - Fen Wang
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Katja Langen
- Department of Radiation Oncology, Emory University, USA
| | | | - Ronny L Rotondo
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Harold H Li
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Ronald C Chen
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| |
Collapse
|
8
|
Zhu M, Langen K, Nichols EM, Lin Y, Flampouri S, Godette KD, Dutta SW, McDonald MW, Patel SA. Intensity Modulated Proton Therapy Treatment Planning for Postmastectomy Patients with Metallic Port Tissue Expanders. Adv Radiat Oncol 2021; 7:100825. [PMID: 34805622 PMCID: PMC8590033 DOI: 10.1016/j.adro.2021.100825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 09/10/2021] [Accepted: 09/26/2021] [Indexed: 11/28/2022] Open
Abstract
Purpose Proton beam therapy can significantly reduce cardiopulmonary radiation exposure compared with photon-based techniques in the postmastectomy setting for locally advanced breast cancer. For patients with metallic port tissue expanders, which are commonly placed in patients undergoing a staged breast reconstruction, dose uncertainties introduced by the high-density material pose challenges for proton therapy. In this report, we describe an intensity modulated proton therapy planning technique for port avoidance through a hybrid single-field optimization/multifield optimization approach. Methods and Materials In this planning technique, 3 beams are utilized. For each beam, no proton spot is placed within or distal to the metal port plus a 5 mm margin. Therefore, precise modeling of the metal port is not required, and various tissue expander manufacturers/models are eligible. The blocked area of 1 beam is dosimetrically covered by 1 or 2 of the remaining beams. Multifield optimization is used in the chest wall target region with blockage of any beam, while single-field optimization is used for remainder of chest wall superior/inferior to the port. Results Using this technique, clinical plans were created for 6 patients. Satisfactory plans were achieved in the 5 patients with port-to-posterior chest wall separations of 1.5 cm or greater, but not in the sixth patient with a 0.7 cm separation. Conclusions We described a planning technique and the results suggest that the metallic port-to-chest wall distance may be a key parameter for optimal plan design.
Collapse
Affiliation(s)
- Mingyao Zhu
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Katja Langen
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Elizabeth M Nichols
- Department of Radiation Oncology, Maryland University School of Medicine, Baltimore, Maryland
| | - Yuting Lin
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Stella Flampouri
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Karen D Godette
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Sunil W Dutta
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Mark W McDonald
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Sagar A Patel
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia
| |
Collapse
|
9
|
Bauer EK, Werner J, Brunn A, Deckert M, Ruess D, Ruge M, Celik E, Fink GR, Langen K, Galldiks N. P14.79 Differentiation of treatment-related changes from tumor progression following brachytherapy in patients with WHO II and III gliomas using FET PET. Neuro Oncol 2021. [DOI: 10.1093/neuonc/noab180.184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
BACKGROUND
Following brachytherapy, the differentiation of radiation-induced changes (e.g., radiation necrosis) from actual tumor progression using MRI is challenging. To overcome this diagnostic uncertainty, we evaluated the diagnostic value of O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in glioma patients treated with brachytherapy.
MATERIAL AND METHODS
From 2006–2019, we retrospectively identified WHO grade II or III glioma patients (i) treated with brachytherapy using Iodine-125 seeds, (ii) equivocal or progressive MRI findings inside the radiation field, and (iii) additional FET PET imaging for diagnostic evaluation. Static FET PET parameters such as maximum and mean tumor-to-brain ratios (TBR) and dynamic FET PET parameters (i.e., time-to-peak, slope) were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses and Fisher’s exact test. Diagnoses were confirmed histologically or clinicoradiologically.
RESULTS
Following brachytherapy, suspect MRI findings occurred after a median time of 33 months (range, 5–111 months). In 10 of 21 patients (WHO grade II, n=5; WHO grade III, n=16), treatment-related changes were diagnosed. The best diagnostic performance for identification of treatment-related changes was obtained using maximum TBRs (threshold <3.20; accuracy, 86%; sensitivity, 100%; specificity, 73%; P=0.007). Mean TBRs reached an accuracy of 76% (threshold <2.05; sensitivity, 89%; specificity, 64%; P=0.010). Dynamic PET parameters did not reach statistically significant results.
CONCLUSION
Our data suggest that static FET PET parameters add valuable diagnostic information to diagnose radiation-induced changes in glioma patients treated with brachytherapy.
Collapse
Affiliation(s)
- E K Bauer
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - J Werner
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - A Brunn
- Inst. of Neuropathology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - M Deckert
- Inst. of Neuropathology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - D Ruess
- Dept. of Stereotaxy and Functional Neurosurgery, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - M Ruge
- Dept. of Stereotaxy and Functional Neurosurgery, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - E Celik
- Dept. of Radiation Oncology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - G R Fink
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Inst. of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - K Langen
- Inst. of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
- Dept. of Nuclear Medicine, University Hospital Aachen, Aachen, Germany
| | - N Galldiks
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Inst. of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| |
Collapse
|
10
|
Galldiks N, Stoffels G, Werner J, Bauer EK, Baues C, Celik E, Ruge MI, Fink GR, Langen K, Lohmann P. OS03.3.A Characterization of long-term metabolic changes of irradiated brain metastases using serial dynamic FET PET imaging. Neuro Oncol 2021. [DOI: 10.1093/neuonc/noab180.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
BACKGROUND
In the present study, we characterized the long-term metabolic changes of brain metastases irradiated with stereotactic radiosurgery (SRS) by sequential dynamic PET imaging using the radiolabeled amino acid O-(2-[18F]-fluoroethyl)-L-tyrosine (FET). We hypothesized that this approach is of considerable clinical value to diagnose delayed radiation-induced changes.
MATERIAL AND METHODS
From 2010–2021, we retrospectively identified patients with brain metastases from solid extracranial primary tumors who (i) were treated with SRS with or without concurrent immunotherapy using checkpoint inhibitors, (ii) had equivocal or progressive MRI findings after SRS, and (iii) subsequently underwent at least two additional dynamic FET PET scans during follow-up for long-term evaluation. Mean tumor-to-brain ratios (TBR) and the dynamic FET PET parameter time-to-peak were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses. Diagnoses were confirmed histologically or clinicoradiologically.
RESULTS
We identified 36 patients with 98 FET PET scans (median number, 3; range, 2–6). Concurrent to SRS, 8 patients (22%) were treated with checkpoint inhibitors. Following SRS, suspicious MRI findings occurred after a median time of 11 months (range, 2–64 months). Subsequently, FET PET scans were acquired over a median period of 13 months (range, 5–60 months). The overall median follow-up time was 26 months (range, 8–101 months). Twenty-one patients (58%) had delayed radiation-induced changes. TBRs calculated from the last available FET PET scan showed the highest accuracy (92%) to identify delayed radiation-induced changes (threshold, 1.95; P<0.001).
CONCLUSION
FET PET has a high diagnostic accuracy for characterizing the long-term changes of irradiated brain metastases.
Collapse
Affiliation(s)
- N Galldiks
- University Hospital Cologne, Cologne, Germany
- Reseach Center Juelich, Juelich, Germany
| | - G Stoffels
- Reseach Center Juelich, Juelich, Germany
| | - J Werner
- University Hospital Cologne, Cologne, Germany
| | - E K Bauer
- University Hospital Cologne, Cologne, Germany
| | - C Baues
- University Hospital Cologne, Cologne, Germany
| | - E Celik
- University Hospital Cologne, Cologne, Germany
| | - M I Ruge
- University Hospital Cologne, Cologne, Germany
| | - G R Fink
- University Hospital Cologne, Cologne, Germany
| | - K Langen
- Reseach Center Juelich, Juelich, Germany
| | - P Lohmann
- Reseach Center Juelich, Juelich, Germany
| |
Collapse
|
11
|
Czerska K, Emert F, Kopec R, Langen K, McClelland JR, Meijers A, Miyamoto N, Riboldi M, Shimizu S, Terunuma T, Zou W, Knopf A, Rucinski A. Clinical practice vs. state-of-the-art research and future visions: Report on the 4D treatment planning workshop for particle therapy - Edition 2018 and 2019. Phys Med 2021; 82:54-63. [PMID: 33588228 DOI: 10.1016/j.ejmp.2020.12.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/09/2020] [Accepted: 12/16/2020] [Indexed: 12/18/2022] Open
Abstract
The 4D Treatment Planning Workshop for Particle Therapy, a workshop dedicated to the treatment of moving targets with scanned particle beams, started in 2009 and since then has been organized annually. The mission of the workshop is to create an informal ground for clinical medical physicists, medical physics researchers and medical doctors interested in the development of the 4D technology, protocols and their translation into clinical practice. The 10th and 11th editions of the workshop took place in Sapporo, Japan in 2018 and Krakow, Poland in 2019, respectively. This review report from the Sapporo and Krakow workshops is structured in two parts, according to the workshop programs. The first part comprises clinicians and physicists review of the status of 4D clinical implementations. Corresponding talks were given by speakers from five centers around the world: Maastro Clinic (The Netherlands), University Medical Center Groningen (The Netherlands), MD Anderson Cancer Center (United States), University of Pennsylvania (United States) and The Proton Beam Therapy Center of Hokkaido University Hospital (Japan). The second part is dedicated to novelties in 4D research, i.e. motion modelling, artificial intelligence and new technologies which are currently being investigated in the radiotherapy field.
Collapse
Affiliation(s)
- Katarzyna Czerska
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland.
| | - Frank Emert
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland
| | - Renata Kopec
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland
| | - Katja Langen
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Jamie R McClelland
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Arturs Meijers
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Naoki Miyamoto
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Hokkaido, Japan; Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Marco Riboldi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Germany
| | - Shinichi Shimizu
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Hokkaido, Japan; Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Toshiyuki Terunuma
- Faculty of Medicine, University of Tsukuba, Japan; Proton Medical Research Center, University of Tsukuba Hospital, Japan
| | - Wei Zou
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Antje Knopf
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Antoni Rucinski
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland
| |
Collapse
|
12
|
Gao H, Lin B, Lin Y, Fu S, Langen K, Liu T, Bradley J. Simultaneous dose and dose rate optimization (SDDRO) for FLASH proton therapy. Med Phys 2020; 47:6388-6395. [PMID: 33068294 DOI: 10.1002/mp.14531] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/25/2020] [Accepted: 09/30/2020] [Indexed: 12/11/2022] Open
Abstract
PURPOSE FLASH radiotherapy (RT) can potentially reduce normal tissue toxicity while preserving tumoricidal effectiveness to improve the therapeutic ratio. The key of FLASH for sparing normal tissues is to irradiate tissues with an ultra-high dose rate (i.e., ≥40 Gy/s), for which proton RT can be used. However, currently available treatment plan optimization method only optimizes the dose distribution and does not directly optimize the dose rate. The contribution of this work to FLASH proton RT is the development of a novel treatment optimization method, that is, simultaneous dose and dose rate optimization (SDDRO), to optimize tissue-receiving dose rate distribution as well as dose distribution. METHODS Distinguished from existing methods, SDDRO accounts for dose rate constraint and optimizes dose rate distribution. In terms of mathematical formulation, SDDRO is a constrained optimization problem with dose-volume constraint on dose distribution, minimum dose rate constraint on dose-averaged tissue-receiving dose rates, minimum monitor unit constraint on spot weight, and maximum intensity constraint on beam intensity. In terms of optimization algorithm, SDDRO is solved by iterative convex relaxation and alternating direction method of multipliers. SDDRO algorithms are presented for both scenarios with either constant or variable beam intensity. RESULTS SDDRO was compared with intensity modulated proton therapy (IMPT) (dose optimization alone, and no dose rate optimization) using three lung cases. SDDRO substantially improved the dose rate distribution compared to IMPT, for example, increasing of the region-of-interest (ROI) volume (ROI = CTV_10mm: the ring sandwiched by 10 mm outer and inner expansion of CTV boundary) receiving at least 40 Gy/s from ~30-50% to at least 98%, and the lung volume receiving at least 40 Gy/s from ~30-40% to ~70-90%. Moreover, both dose and dose rate distributions from SDDRO were further considerably improved via the combined use of hypofractionation and multiple beams. CONCLUSIONS We have developed a joint dose and dose rate optimization method for FLASH proton RT, namely SDDRO, which is first-of-its-kind to the best of our knowledge. The results suggest that (a) SDDRO can substantially improve the FLASH-dose rate coverage (e.g., in terms of dose rate volume histogram) compared to IMPT for the purpose of normal tissue sparing while preserving the dose distribution and (b) the combination of hypofractionation and multiple beams can further considerably improve the SDDRO plan quality in terms of both dose and dose rate distribution.
Collapse
Affiliation(s)
- Hao Gao
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Bowen Lin
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA.,School of Mathematics, Shandong University, Jinan, Shandong, China
| | - Yuting Lin
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Shujun Fu
- School of Mathematics, Shandong University, Jinan, Shandong, China
| | - Katja Langen
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Tian Liu
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Jeffery Bradley
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| |
Collapse
|
13
|
Lipsanen T, Korkeila J, Peltola P, Järvinen J, Langen K, Lauerma H. Dissociative disorders among psychiatric patients. Eur Psychiatry 2020; 19:53-5. [PMID: 14969781 DOI: 10.1016/j.eurpsy.2003.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2002] [Revised: 08/26/2003] [Accepted: 09/11/2003] [Indexed: 11/19/2022] Open
Abstract
AbstractThe aim was to determine the rate of dissociative disorders among psychiatric in- (n = 34) and out-patients (n = 37) and to compare the rate to that of nonclinical subjects (n = 297). Dissociative disorders (17% of patients) could be grouped according to the severity of the symptoms and their relation to affective disorders.
Collapse
|
14
|
Chang CW, Huang S, Harms J, Zhou J, Zhang R, Dhabaan A, Slopsema R, Kang M, Liu T, McDonald M, Langen K, Lin L. A standardized commissioning framework of Monte Carlo dose calculation algorithms for proton pencil beam scanning treatment planning systems. Med Phys 2020; 47:1545-1557. [PMID: 31945191 DOI: 10.1002/mp.14021] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 01/03/2020] [Accepted: 01/04/2020] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Treatment planning systems (TPSs) from different vendors can involve different implementations of Monte Carlo dose calculation (MCDC) algorithms for pencil beam scanning (PBS) proton therapy. There are currently no guidelines for validating non-water materials in TPSs. Furthermore, PBS-specific parameters can vary by 1-2 orders of magnitude among different treatment delivery systems (TDSs). This paper proposes a standardized framework on the use of commissioning data and steps to validate TDS-specific parameters and TPS-specific heterogeneity modeling to potentially reduce these uncertainties. METHODS A standardized commissioning framework was developed to commission the MCDC algorithms of RayStation 8A and Eclipse AcurosPT v13.7.20 using water and non-water materials. Measurements included Bragg peak depth-dose and lateral spot profiles and scanning field outputs for Varian ProBeam. The phase-space parameters were obtained from in-air measurements and the number of protons per MU from output measurements of 10 × 10 cm2 square fields at a 2 cm depth. Spot profiles and various PBS field measurements at additional depths were used to validate TPS. Human tissues in TPS, Gammex phantom materials, and artificial materials were used for the TPS benchmark and validation. RESULTS The maximum differences of phase parameters, spot sigma, and divergence between MCDC algorithms are below 4.5 µm and 0.26 mrad in air, respectively. Comparing TPS to measurements at depths, both MC algorithms predict the spot sigma within 0.5 mm uncertainty intervals, the resolution of the measurement device. Beam Configuration in AcurosPT is found to underestimate number of protons per MU by ~2.5% and requires user adjustment to match measured data, while RayStation is within 1% of measurements using Auto model. A solid water phantom was used to validate the range accuracy of non-water materials within 1% in AcurosPT. CONCLUSIONS The proposed standardized commissioning framework can detect potential issues during PBS TPS MCDC commissioning processes, and potentially can shorten commissioning time and improve dosimetric accuracies. Secondary MCDC can be used to identify the root sources of disagreement between primary MCDC and measurement.
Collapse
Affiliation(s)
- Chih-Wei Chang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
| | - Sheng Huang
- Memorial Sloan Kettering Cancer Center, New York City, NY, 10065, USA
| | - Joseph Harms
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
| | - Jun Zhou
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
| | - Rongxiao Zhang
- Department of Radiation Oncology, Dartmouth College, Hanover, NH, USA
| | - Anees Dhabaan
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
| | - Roelf Slopsema
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
| | - Minglei Kang
- New York Proton Center, New York, NY, 10035, USA
| | - Tian Liu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
| | - Mark McDonald
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
| | - Katja Langen
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
| | - Liyong Lin
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
| |
Collapse
|
15
|
Wang P, Tang S, Leach K, Mangona V, Simone CB, Langen K, Chang C. Proton pencil beam scanning treatment with feedback based voluntary moderate breath hold. Med Dosim 2019; 45:e10-e15. [PMID: 31870600 DOI: 10.1016/j.meddos.2019.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/18/2019] [Accepted: 11/18/2019] [Indexed: 11/27/2022]
Abstract
Introduction The aim of this article is to introduce a novel protocol for proton pencil beam scanning treatment with moderate deep inspiration breath hold (mDIBH) and report on our clinical implementation results. Methods Three computed tomography (CT) scannings to build the patient's anatomy model were performed during the patient's voluntary mDIBH. All 3 CT scans were used in the optimization during the treatment planning process. Both orthogonal kV imaging and cone-beam computed tomography (CBCT) were implemented for patient alignment with BH prior to the treatment. The BH CBCT images were analyzed for BH reproducibility and the virtual total dose (VTD) retrospectively. To find the VTD, a series of deformable image registrations (DIR) were performed between CBCT and pCT. The effect of the variation of lung density on the dose distribution was also analyzed in the study. Results The values of the mean, standard deviation, maximum, and minimum of the tumor location difference between the CBCT and pCT were 1.9, 1.6, 4.7, and 0.0 mm, respectively. The percentage difference in D99% of CTVs between VTD and the nominal plan was within 1.5%. Conclusions The feedback-based voluntary moderate BH proton PBS treatment was successfully performed in our clinic. This study shows that there is a potential to implement the BH treatment widely in proton centers.
Collapse
Affiliation(s)
- Peng Wang
- Department of Radiation Oncology, Inova Health System, Falls Church, VA, USA.
| | - Shikui Tang
- Texas Center for Proton Therapy, Irving, TX, USA
| | - Karla Leach
- Texas Center for Proton Therapy, Irving, TX, USA
| | | | | | | | - Chang Chang
- California Protons Ca Therapy Center, San Diego, CA, USA
| |
Collapse
|
16
|
Lohmann P, Stavrinou P, Lipke K, Bauer EK, Ceccon G, Werner J, Fink GR, Shah NJ, Langen K, Galldiks N. P14.32 Spatial discrepancies between FET PET and conventional MRI in patients with newly diagnosed glioblastoma. Neuro Oncol 2019. [DOI: 10.1093/neuonc/noz126.267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
BACKGROUND
In patients with glioblastoma, the tissue showing contrast enhancement (CE) in MRI is usually the target for resection or radiotherapy. However, the solid tumor mass typically extends beyond the area of CE. Amino acid PET can detect tumor parts that show no CE. We systematically investigated tumor volumes delineated by amino acid PET and MRI in newly diagnosed, untreated glioblastoma patients.
MATERIAL AND METHODS
Preoperatively, 50 patients with subsequently neuropathologically confirmed glioblastoma underwent O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET, fluid-attenuated inversion recovery (FLAIR), and CE MRI. Areas of CE were manually delineated. FET PET tumor volumes were segmented using a tumor-to-brain ratio ≥ 1.6. The percentage of overlapping volumes (OV), as well as Dice and Jaccard spatial similarity coefficients (DSC; JSC), were calculated. FLAIR images were evaluated visually.
RESULTS
In 86% of patients (n = 43), the FET PET tumor volume was significantly larger than the volume of CE (21.5 ± 14.3 mL vs. 9.4 ± 11.3 mL; P < 0.001). Forty patients (80%) showed both an increased uptake of FET and CE. In these 40 patients, the spatial similarity between FET and CE was low (mean DSC, 0.39 ± 0.21; mean JSC, 0.26 ± 0.16). Ten patients (20%) showed no CE, and one of these patients showed no FET uptake. In 10% of patients (n = 5), increased FET uptake was present outside of areas of FLAIR hyperintensity.
CONCLUSION
Our results show that the metabolically active tumor volume delineated by FET PET is significantly larger than tumor volume delineated by CE. The data strongly suggest that the information derived from FET PET should be integrated into the management of newly diagnosed glioblastoma patients.
FUNDING
This work was supported by the Wilhelm-Sander Stiftung, Germany
Collapse
Affiliation(s)
- P Lohmann
- Institute of Neuroscience and Medicine (INM-3,-4), Research Center Juelich, Juelich, Germany
| | - P Stavrinou
- Department of Neurosurgery, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - K Lipke
- Institute of Neuroscience and Medicine (INM-3,-4), Research Center Juelich, Juelich, Germany
| | - E K Bauer
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - G Ceccon
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - J Werner
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - G R Fink
- Institute of Neuroscience and Medicine (INM-3,-4), Research Center Juelich, Juelich, Germany
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - N J Shah
- Institute of Neuroscience and Medicine (INM-3,-4), Research Center Juelich, Juelich, Germany
- Department of Neurology, University Hospital RWTH Aachen, Aachen, Germany
| | - K Langen
- Institute of Neuroscience and Medicine (INM-3,-4), Research Center Juelich, Juelich, Germany
- Department of Nuclear Medicine, University Hospital RWTH Aachen, Aachen, Germany
| | - N Galldiks
- Institute of Neuroscience and Medicine (INM-3,-4), Research Center Juelich, Juelich, Germany
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| |
Collapse
|
17
|
Werner J, Stoffels G, Lichtenstein T, Borggrefe J, Lohmann P, Ceccon G, Fink GR, Langen K, Kabbasch C, Galldiks N. P14.17 Differentiation of treatment-related changes from tumor progression: A direct comparison between dynamic FET PET and ADC values obtained from DWI MRI. Neuro Oncol 2019. [DOI: 10.1093/neuonc/noz126.252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
BACKGROUND
Following brain cancer treatment, the capacity of anatomical MRI to differentiate neoplastic tissue from treatment-related changes (e.g., pseudoprogression) is limited. This study compared apparent diffusion coefficients (ADC) obtained by diffusion-weighted MRI (DWI) with static and dynamic parameters of O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET for the differentiation of treatment-related changes from tumor progression.
MATERIAL AND METHODS
Forty-eight pretreated high-grade glioma patients with anatomical MRI findings suspicious for progression (median time elapsed since last treatment, 16 weeks) were investigated using DWI and dynamic FET PET. Maximum and mean tumor-to-brain ratios (TBRmax, TBRmean) as well as dynamic parameters (time-to-peak and slope values) of FET uptake were calculated. For mean ADC calculation, regions-of-interest analyses were performed on ADC maps calculated from DWI co-registered with the contrast-enhanced MR image. Diagnoses were confirmed neuropathologically (21%) or clinicoradiologically. Diagnostic performance was evaluated using receiver-operating-characteristic analyses or Fisher’s exact test for a combinational approach.
RESULTS
Ten of 48 patients had treatment-related changes (21%). The diagnostic performance of FET PET was significantly higher (threshold for both TBRmax and TBRmean, 1.95; accuracy, 83%; AUC, 0.89±0.05; P<0.001) than that of ADC values (threshold ADC, 1.09x10-3 mm2/s; accuracy, 69%; AUC, 0.73±0.09; P=0.13). The addition of static FET PET parameters to ADC values increased the latter’s accuracy to 89%. The highest accuracy was achieved by combining static and dynamic FET PET parameters (93%).
CONCLUSION
Data suggest that static and dynamic FET PET provide valuable information concerning the differentiation of early treatment-related changes from tumor progression and outperform ADC measurement for this highly relevant clinical question.
Collapse
Affiliation(s)
- J Werner
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - G Stoffels
- Inst. of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - T Lichtenstein
- Dept. of Neuroradiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - J Borggrefe
- Dept. of Neuroradiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - P Lohmann
- Inst. of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - G Ceccon
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - G R Fink
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Inst. of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - K Langen
- Inst. of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
- Dept. of Nuclear Medicine, University Hospital Aachen, Aachen, Germany
| | - C Kabbasch
- Dept. of Neuroradiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - N Galldiks
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Inst. of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| |
Collapse
|
18
|
Mueller M, Kamp M, Sabel M, Stoffels G, Galldiks N, Langen K, Rapp M. P04.07 Correlation of 18F-fluorethyl-L-tyrosine (18F-FET) uptake in positron emission tomography (PET) and MRI growth rate in low-grade glioma. Neuro Oncol 2019. [DOI: 10.1093/neuonc/noz126.102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
BACKGROUND
Low-grade gliomas (LGGs, WHO grade II) are a heterogeneous group of tumors of the central nervous system with diverse behavior in histopathology, genetics and growth patterns. Therefore, different therapeutic strategies are discussed ranging from watchful waiting to radical resection and adjuvant radio-/chemotherapy. For a better evaluation of tumor progression or malignant transformation, the O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) uptake in PET or the tumor growth rate assessed on MRI are used depending on the neurooncological center. Here, we correlated both methods.
MATERIAL AND METHODS
Inclusion criteria for this retrospective study were (1) newly diagnosed and neuropathologically confirmed low-grade glioma; (2) at least two MRIs at initial diagnosis and follow-up for calculation of the tumor growth rate (using IDS7 by Sectra AB, Sweden, 2018); (3) and an additional preoperative 18F-FET PET scan.
RESULTS
From 2008 to 2018, 34 patients were identified (mean age 39.7 years; 68% diffuse astrocytoma). The mean tumor growth rate on MRI was 0.091 cm3/d. The average mean 18F-FET uptake was 1.42; the average maximum 18F-FET uptake was 2.18. The Pearson correlation coefficient between the tumor growth rate and the mean and maximum 18F-FET uptake was r=0.19, and r=0.10. In the group of diffuse astrocytomas, the mean growth rate in tumors with a mean 18F-FET uptake of >1.5 was significantly higher than the mean growth rate of those with a mean 18F-FET uptake of ≤1.5 (p<0.1).
CONCLUSION
Data suggest that astrocytic LGGs with increased 18F-FET uptake may show a more aggressive behaviour, with a potentially higher risk for an earlier tumor progression or malignant transformation. For further elucidation of a correlation between the tumor growth rate and the 18F-FET uptake, larger prospective studies are needed. In the future, the combination of both methods in the management of low-grade gliomas could help to detect tumor progression as well as tumor malignization more precisely.
Collapse
Affiliation(s)
- M Mueller
- Department of Neurosurgery University Medical Center Duesseldorf, Duesseldorf, Germany
| | - M Kamp
- Department of Neurosurgery University Medical Center Duesseldorf, Duesseldorf, Germany
| | - M Sabel
- Department of Neurosurgery University Medical Center Duesseldorf, Duesseldorf, Germany
| | - G Stoffels
- Research Center Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich, Germany
| | - N Galldiks
- Research Center Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich, Germany
- Department of Neurology, University Hospital Cologne, Cologne, Germany
| | - K Langen
- Research Center Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich, Germany
| | - M Rapp
- Department of Neurosurgery University Medical Center Duesseldorf, Duesseldorf, Germany
| |
Collapse
|
19
|
Bauer EK, Stoffels G, Blau T, Reifenberger G, Werner JM, Lohmann P, Rapp M, Fink GR, Langen K, Galldiks N. P14.29 Prediction of overall survival in patients with malignant glioma using dynamic O-(2-[18F]-fluoroethyl)-L-tyrosine PET. Neuro Oncol 2019. [DOI: 10.1093/neuonc/noz126.264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
BACKGROUND
Characterization of gliomas according to the revised World Health Organization (WHO) classification of 2016 has gained major importance regarding prognostication. The present study aimed at exploring the prognostic value of dynamic O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in newly diagnosed and molecularly defined astrocytic high-grade glioma (HGG) of the WHO grades III or IV.
MATERIAL AND METHODS
Before initiation of treatment, dynamic FET PET imaging was performed in patients with newly diagnosed glioblastoma (GBM) and anaplastic astrocytoma (AA). Static FET PET parameters such as maximum and mean tumor/brain ratios (TBRmax/mean), as well as the dynamic FET PET parameters time-to-peak (TTP) and slope, were obtained. The predictive ability of FET PET parameters was evaluated with regard to the overall survival (OS). Using ROC analyses, threshold values for FET PET parameters were obtained. Subsequently, univariate Kaplan-Meier and multivariate Cox regression survival analyses were performed to assess their predictive power for OS.
RESULTS
Sixty patients (45 GBM, 15 AA) of two university centers were retrospectively identified. Patients with a methylated MGMT promoter as well as with an IDH mutation had a significantly longer OS (both P<0.001). Furthermore, ROC analysis revealed in IDH-wildtype HGG (n=45) that a TTP>25 minutes (AUC, 0.90; sensitivity, 90%; specificity, 87%; P<0.001) was highly prognostic for a longer OS (29 vs. 12 months; P<0.001). Besides a complete resection and a methylated MGMT promoter, TTP remained significant in the multivariate survival analysis (P=0.002, P=0.016, and P=0.003, respectively), indicating an independent predictor for OS. In contrast, both TBRmax and TBRmean were not prognostic (AUC, 0.37 and 0.32, respectively).
CONCLUSION
Data suggest that within the subgroup of patients with newly diagnosed and untreated IDH-wildtype GBM and AA, dynamic FET PET additionally allows the identification of patients with an improved OS.
Collapse
Affiliation(s)
- E K Bauer
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - G Stoffels
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - T Blau
- Dept. of Neuropathology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - G Reifenberger
- Dept. of Neuropathology, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
- Center of Integrated Oncology (CIO), Universities of Aachen, Bonn, Cologne and Duesseldorf, Aachen, Bonn, Cologne and Duesseldorf, Germany
| | - J M Werner
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - P Lohmann
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - M Rapp
- Dept. of Neurosurgery, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - G R Fink
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - K Langen
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
- Dept. of Nuclear Medicine, University of Aachen, Aachen, Germany
| | - N Galldiks
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| |
Collapse
|
20
|
Rosen J, Stoffels G, Lohmann P, Bauer EK, Werner J, Rapp M, Felsberg J, Fink GR, Langen K, Galldiks N. P14.18 Prognostic value of serial dynamic O-(2-[18F]-fluoroethyl)-L-tyrosine PET in patients with non-resectable malignant glioma undergoing chemoradiation. Neuro Oncol 2019. [DOI: 10.1093/neuonc/noz126.253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
BACKGROUND
A complete resection of high-grade gliomas (HGG) is associated with improved survival, which, however, cannot be achieved in a considerable number of patients. We here evaluated the prognostic value of serial O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in patients with newly diagnosed, non-resectable astrocytic HGG undergoing chemoradiation with temozolomide.
MATERIAL AND METHODS
Serial dynamic FET PET scans were performed in 18 newly diagnosed patients with molecularly defined, non-resectable HGG at baseline and after chemoradiation (8±3 weeks). Both static (tumor/brain ratios, FET tumor volumes) and dynamic FET PET parameters (time-to-peak, slope), as well as MRI changes according to RANO criteria at first follow-up after chemoradiation (8±3 weeks), were obtained. The predictive ability of FET PET parameters and RANO criteria was evaluated with regard to the progression-free survival (PFS). Using ROC analyses, threshold values for FET PET parameters were obtained. Subsequently, univariate and multivariate survival analyses were performed to assess their predictive power for PFS.
RESULTS
ROC analysis revealed that the mean tumor/brain ratio (AUC, 0.84), FET tumor volume (AUC, 0.89), and slope (AUC, 0.72) at baseline were predictive for a prolonged PFS (9.3 vs. 5.7 months, P=0.05; 10.3 vs. 5.9 months; P=0.03; 13.5 vs. 6.2 months, P=0.02, respectively). Furthermore, FET tumor volume and slope remained significant in the multivariate survival analysis (both P<0.05). In contrast, relative changes of static or dynamic FET PET parameters at follow-up and MRI changes according to RANO criteria were not significant in this albeit small series of patients.
CONCLUSION
Results suggest that before initiation of chemoradiation FET PET parameters at baseline can be used to predict PFS in patients with non-resectable HGG.
Collapse
Affiliation(s)
- J Rosen
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - G Stoffels
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - P Lohmann
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - E K Bauer
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - J Werner
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - M Rapp
- Dept. of Neurosurgery, University Hospital Duesseldorf, Duesseldorf, Germany
| | - J Felsberg
- Dept. of Neuropathology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - G R Fink
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| | - K Langen
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
- Dept. of Nuclear Medicine, University Hospital Aachen, Aachen, Germany
| | - N Galldiks
- Dept. of Neurology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany
| |
Collapse
|
21
|
Wang P, Zhu M, Langen K. Technical Note: Quality assurance of proton central axis pencil‐beam spread‐out Bragg peak using large‐diameter multilayer ionization chambers. Med Phys 2019; 46:4685-4689. [DOI: 10.1002/mp.13732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/13/2019] [Accepted: 07/08/2019] [Indexed: 11/08/2022] Open
Affiliation(s)
- Peng Wang
- Department of Radiation Oncology University of Maryland School of Medicine Baltimore MD21201USA
| | - Mingyao Zhu
- Department of Radiation Oncology University of Maryland School of Medicine Baltimore MD21201USA
| | - Katja Langen
- Department of Radiation Oncology University of Maryland School of Medicine Baltimore MD21201USA
| |
Collapse
|
22
|
Abstract
Concepts of planning target volume and plan robustness in proton therapy are described. Implementation of these concepts into treatment planning is described. Proton plan sensitivity and interfractional and intrafractional anatomical variation are also discussed.
Collapse
Affiliation(s)
- Katja Langen
- Department of Radiation Oncology, Maryland Proton Treatment Center, University of Maryland School of Medicine, Baltimore, MD.
| | - Mingyao Zhu
- Department of Radiation Oncology, Maryland Proton Treatment Center, University of Maryland School of Medicine, Baltimore, MD
| |
Collapse
|
23
|
Lohmann P, Stavrinou P, Lipke K, Bauer EK, Ceccon G, Werner J, Fink GR, Shah NJ, Langen K, Galldiks N. P01.014 Spatial correlation of FET uptake and MRI contrast enhancement in newly diagnosed glioblastoma patients prior to treatment. Neuro Oncol 2018. [DOI: 10.1093/neuonc/noy139.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- P Lohmann
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
| | - P Stavrinou
- Dept. of Neurosurgery, University Cologne, Cologne, Germany
| | - K Lipke
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
| | - E K Bauer
- Dept. of Neurology, University of Cologne, Cologne, Germany
| | - G Ceccon
- Dept. of Neurology, University of Cologne, Cologne, Germany
| | - J Werner
- Dept. of Neurology, University of Cologne, Cologne, Germany
| | - G R Fink
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Neurology, University of Cologne, Cologne, Germany
| | - N J Shah
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Neurology, University Hospital RWTH Aachen, Aachen, Germany
| | - K Langen
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Nuclear Medicine, University Hospital RWTH Aachen, Aachen, Germany
| | - N Galldiks
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Neurology, University of Cologne, Cologne, Germany
| |
Collapse
|
24
|
Lohmann P, Kocher M, Ceccon G, Bauer EK, Stoffels G, Viswanathan S, Ruge MI, Neumaier B, Shah NJ, Fink GR, Langen K, Galldiks N. P05.11 Combined FET PET/MRI radiomics for the differentiation of radiation injury from recurrent brain metastasis. Neuro Oncol 2018. [DOI: 10.1093/neuonc/noy139.337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- P Lohmann
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne, Germany
| | - M Kocher
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne, Germany
| | - G Ceccon
- Dept. of Neurology, University of Cologne, Cologne, Germany
| | - E K Bauer
- Dept. of Neurology, University of Cologne, Cologne, Germany
| | - G Stoffels
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
| | - S Viswanathan
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
| | - M I Ruge
- Dept. of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne, Germany
| | - B Neumaier
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
| | - N J Shah
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Neurology, University Hospital RWTH Aachen, Aachen, Germany
| | - G R Fink
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Neurology, University of Cologne, Cologne, Germany
| | - K Langen
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Nuclear Medicine, University Hospital RWTH Aachen, Aachen, Germany
| | - N Galldiks
- Inst. of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich, Germany
- Dept. of Neurology, University of Cologne, Cologne, Germany
| |
Collapse
|
25
|
Chuong M, Badiyan SN, Yam M, Li Z, Langen K, Regine W, Morris C, Snider J, Mehta M, Huh S, Rutenberg M, Nichols RC. Pencil beam scanning versus passively scattered proton therapy for unresectable pancreatic cancer. J Gastrointest Oncol 2018; 9:687-693. [PMID: 30151265 DOI: 10.21037/jgo.2018.03.14] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Background With an increasing number of proton centers capable of delivering pencil beam scanning (PBS), understanding the dosimetric differences in PBS compared to passively scattered proton therapy (PSPT) for pancreatic cancer is of interest. Methods Optimized PBS plans were retrospectively generated for 11 patients with locally advanced pancreatic cancer previously treated with PSPT to 59.4 Gy on a prospective trial. The primary tumor was targeted without elective nodal coverage. The same treatment couch, target coverage and normal tissue dose objectives were used for all plans. A Wilcoxon t-test was performed to compare various dosimetric points between the two plans for each patient. Results All target volume coverage goals were met in all PBS and passive scattering (PS) plans, except for the planning target volume (PTV) coverage goal (V100% >95%) which was not met in one PS plan (range, 81.8-98.9%). PBS was associated with a lower median relative dose (102.4% vs. 103.8%) to 10% of the PTV (P=0.001). PBS plans had a lower median duodenal V59.4 Gy (37.4% vs. 40.4%; P=0.014), lower small bowel median V59.4 Gy (0.11% vs. 0.37%; P=0.012), lower stomach median V59.4 Gy (0.01% vs. 0.1%; P=0.023), and lower median dose to 0.1 cc of the spinal cord {35.0 vs. 38.7 Gy [relative biological effectiveness (RBE)]; P=0.001}. Liver dose was higher in PBS plans for median V5 Gy (24.1% vs. 20.2%; P=0.032), V20 Gy (3.2% vs. 2.8%; P=0.010), and V25 Gy (2.6% vs. 2.2%; P=0.019). There was no difference in kidney dose between PBS and PS plans. Conclusions Proton therapy for locally advanced pancreatic cancer using PBS was not clearly associated with clinically meaningful reductions in normal tissue dose compared to PS. Some statistically significant improvements in PTV coverage were achieved using PBS. PBS may offer improved conformality for the treatment of irregular targets, and further evaluation of PBS and PS incorporating elective nodal irradiation should be considered.
Collapse
Affiliation(s)
- Michael Chuong
- Miami Cancer Institute, Baptist Health South Florida, Miami, FL, USA
| | - Shahed N Badiyan
- University of Maryland Medical School of Medicine, Baltimore, MD, USA
| | - Man Yam
- Miami Cancer Institute, Baptist Health South Florida, Miami, FL, USA
| | - Zuofeng Li
- University of Florida Proton Therapy Institute, Jacksonville, FL, USA
| | - Katja Langen
- University of Maryland Medical School of Medicine, Baltimore, MD, USA
| | - William Regine
- University of Maryland Medical School of Medicine, Baltimore, MD, USA
| | | | - James Snider
- University of Maryland Medical School of Medicine, Baltimore, MD, USA
| | - Minesh Mehta
- Miami Cancer Institute, Baptist Health South Florida, Miami, FL, USA
| | - Soon Huh
- University of Florida Proton Therapy Institute, Jacksonville, FL, USA
| | - Michael Rutenberg
- University of Florida Proton Therapy Institute, Jacksonville, FL, USA
| | - Romaine C Nichols
- University of Florida Proton Therapy Institute, Jacksonville, FL, USA
| |
Collapse
|
26
|
Poulsen PR, Eley J, Langner U, Simone CB, Langen K. Efficient Interplay Effect Mitigation for Proton Pencil Beam Scanning by Spot-Adapted Layered Repainting Evenly Spread out Over the Full Breathing Cycle. Int J Radiat Oncol Biol Phys 2017; 100:226-234. [PMID: 29254775 DOI: 10.1016/j.ijrobp.2017.09.043] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 09/06/2017] [Accepted: 09/22/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE To develop and implement a practical repainting method for efficient interplay effect mitigation in proton pencil beam scanning (PBS). METHODS AND MATERIALS A new flexible repainting scheme with spot-adapted numbers of repainting evenly spread out over the whole breathing cycle (assumed to be 4 seconds) was developed. Twelve fields from 5 thoracic and upper abdominal PBS plans were delivered 3 times using the new repainting scheme to an ion chamber array on a motion stage. One time was static and 2 used 4-second, 3-cm peak-to-peak sinusoidal motion with delivery started at maximum inhalation and maximum exhalation. For comparison, all dose measurements were repeated with no repainting and with 8 repaintings. For each motion experiment, the 3%/3-mm gamma pass rate was calculated using the motion-convolved static dose as the reference. Simulations were first validated with the experiments and then used to extend the study to 0- to 5-cm motion magnitude, 2- to 6-second motion periods, patient-measured liver tumor motion, and 1- to 6-fraction treatments. The effect of the proposed method was evaluated for the 5 clinical cases using 4-dimensional (4D) dose reconstruction in the planning 4D computed tomography scan. The target homogeneity index, HI = (D2 - D98)/Dmean, of a single-fraction delivery is reported, where D2 and D98 is the dose delivered to 2% and 98% of the target, respectively, and Dmean is the mean dose. RESULTS The gamma pass rates were 59.6% ± 9.7% with no repainting, 76.5% ± 10.8% with 8 repaintings, and 92.4% ± 3.8% with the new repainting scheme. Simulations reproduced the experimental gamma pass rates with a 1.3% root-mean-square error and demonstrated largely improved gamma pass rates with the new repainting scheme for all investigated motion scenarios. One- and two-fraction deliveries with the new repainting scheme had gamma pass rates similar to those of 3-4 and 6-fraction deliveries with 8 repaintings. The mean HI for the 5 clinical cases was 14.2% with no repainting, 13.7% with 8 repaintings, 12.0% with the new repainting scheme, and 11.6% for the 4D dose without interplay effects. CONCLUSIONS A novel repainting strategy for efficient interplay effect mitigation was proposed, implemented, and shown to outperform conventional repainting in experiments, simulations, and dose reconstructions. This strategy could allow for safe and more optimal clinical delivery of thoracic and abdominal proton PBS and better facilitate hypofractionated and stereotactic treatments.
Collapse
Affiliation(s)
| | - John Eley
- Maryland Proton Treatment Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ulrich Langner
- Maryland Proton Treatment Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Charles B Simone
- Maryland Proton Treatment Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Katja Langen
- Maryland Proton Treatment Center, University of Maryland School of Medicine, Baltimore, Maryland
| |
Collapse
|
27
|
Langner UW, Eley JG, Dong L, Langen K. Comparison of multi-institutional Varian ProBeam pencil beam scanning proton beam commissioning data. J Appl Clin Med Phys 2017; 18:96-107. [PMID: 28422381 PMCID: PMC5689862 DOI: 10.1002/acm2.12078] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/24/2017] [Accepted: 03/06/2017] [Indexed: 11/09/2022] Open
Abstract
Purpose Commissioning beam data for proton spot scanning beams are compared for the first two Varian ProBeam sites in the United States, at the Maryland Proton Treatment Center (MPTC) and Scripps Proton Therapy Center (SPTC). In addition, the extent to which beams can be matched between gantry rooms at MPTC is investigated. Method Beam data for the two sites were acquired with independent dosimetry systems and compared. Integrated depth dose curves (IDDs) were acquired with Bragg peak ion chambers in a 3D water tank for pencil beams at both sites. Spot profiles were acquired at different distances from the isocenter at a gantry angle of 0° as well as a function of gantry angles. Absolute dose calibration was compared between SPTC and the gantries at MPTC. Dosimetric verification of test plans, output as a function of gantry angle, monitor unit (MU) linearity, end effects, dose rate dependence, and plan reproducibility were compared for different gantries at MPTC. Results The IDDs for the two sites were similar, except in the plateau region, where the SPTC data were on average 4.5% higher for lower energies. This increase in the plateau region decreased as energy increased, with no marked difference for energies higher than 180 MeV. Range in water coincided for all energies within 0.5 mm. The sigmas of the spot profiles in air were within 10% agreement at isocenter. This difference increased as detector distance from the isocenter increased. Absolute doses for the gantries measured at both sites were within 1% agreement. Test plans, output as function of gantry angle, MU linearity, end effects, dose rate dependence, and plan reproducibility were all within tolerances given by TG142. Conclusion Beam data for the two sites and between different gantry rooms were well matched.
Collapse
Affiliation(s)
- Ulrich W Langner
- Department of Radiation Oncology, Maryland Proton Treatment Center, University of Maryland School of Medicine, 850 W. Baltimore Street, Baltimore, MD, 21201, USA
| | - John G Eley
- Department of Radiation Oncology, Maryland Proton Treatment Center, University of Maryland School of Medicine, 850 W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Lei Dong
- Scripps Proton Therapy Center, 9730 Summers Ridge Road, San Diego, CA, 92121, USA
| | - Katja Langen
- Department of Radiation Oncology, Maryland Proton Treatment Center, University of Maryland School of Medicine, 850 W. Baltimore Street, Baltimore, MD, 21201, USA
| |
Collapse
|
28
|
Lohmann P, Lerche C, Bauer E, Steger J, Stoffels G, Filss CP, Stegmayr C, Neumaier B, Shah NJ, Langen K, Galldiks N. P10.17 Predicting isocitrate dehydrogenase genotype in malignant glioma using FET PET radiomics. Neuro Oncol 2017. [DOI: 10.1093/neuonc/nox036.335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
29
|
Lohmann P, Lerche C, Stoffels G, Filss CP, Stegmayr C, Neumaier B, Shah NJ, Langen K, Galldiks N. P09.26 FET PET radiomics - diagnosis of pseudoprogression in glioblastoma patients based on textural features. Neuro Oncol 2017. [DOI: 10.1093/neuonc/nox036.282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
30
|
Yu J, Park SS, Herman MG, Langen K, Mehta M, Feigenberg SJ. Free Breathing versus Breath-Hold Scanning Beam Proton Therapy and Cardiac Sparing in Breast Cancer. Int J Part Ther 2017; 3:407-413. [PMID: 31772990 DOI: 10.14338/ijpt-16-00021.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 11/16/2016] [Indexed: 12/25/2022] Open
Abstract
Purpose To assess dose errors caused by the interplay effects of free-breathing (FB) motion and to assess the value of breath-hold (BH) in terms of cardiac dose reduction for scanning beam proton therapy (SBPT). Materials and Methods Three patients with left-sided breast cancer previously treated with photon therapy were included in this dosimetric study: 2 following breast-conserving surgery with 2 hypothetical target volumes (whole breast alone and whole breast plus regional nodes, including supraclavicular, axillary, and internal mammary lymph nodes); and 1 postmastectomy, with the target volume including the chest wall plus regional nodes. SBPT plans were generated with various beam angles that ranged between 2 tangential directions. For treatment with FB, nominal dose and dose with interplay effects considered were calculated based on FB 4-dimensional computed tomography scans. SBPT plans on the BH computed tomography were also calculated for one of the patients, who was selected to be treated with photon therapy with BH. Results Dosimetric differences between nominal and interplay dose were small (average target mean dose, -0.06 Gy; range, -0.23 to 0.06 Gy; average heart mean dose, 0.001 Gy; range, -0.12 to 0.05 Gy). The largest dose deviations occurred in plans calculated with tangential beam arrangements; the smallest was noted with the en face beam. The average value of the mean heart dose with FB was <1 Gy. For the selected patient, the mean heart doses were 0.5 and 0.2 Gy for FB and BH, respectively. Conclusion Dose deviations caused by the interplay effects of respiratory motion during FB do not have a significant impact in SBPT with en face beam arrangement. BH does not significantly reduce cardiac dose. SBPT delivery is feasible with FB and can provide optimal target coverage and maximal sparing of the cardiopulmonary system, which can translate into improved clinical outcomes and a decrease in treatment-related morbidity in left-sided breast cancer patients or those who require internal mammary node coverage.
Collapse
Affiliation(s)
- Jen Yu
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sean S Park
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Michael G Herman
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Katja Langen
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Minesh Mehta
- Radiation Oncology Department, Baptist Hospital South Florida, Miami, FL, USA
| | - Steven J Feigenberg
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
| |
Collapse
|
31
|
Affiliation(s)
- Arpit Chhabra
- Department of Radiation Oncology, The University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Katja Langen
- Department of Radiation Oncology, The University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Minesh P Mehta
- Department of Radiation Oncology, Miami Cancer Institute, Miami, FL, USA.
| |
Collapse
|
32
|
Langner U, Langen K, Eley J, Zhu M, Yu J, Chung H, Polf J, Dong L. SU-F-T-162: Comparison of Beam Data for Two Varian ProBeam Pencil Beam Scanning Proton Systems. Med Phys 2016. [DOI: 10.1118/1.4956298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
33
|
Mossahebi S, Langen K, Guerrero M, Yi B, Lu W, Kalavagunta C, Prado K, Chen S. SU-F-T-286: Calculation-Based Patient Specific IMRT QA Detects Potential Errors That Measurement-Based QA Does Not. Med Phys 2016. [DOI: 10.1118/1.4956426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
34
|
Yu J, Nichols E, Strauss D, Chung H, Langner U, Langen K. SU-F-T-151: Measurement Evaluation of Skin Dose in Scanning Proton Beam Therapy for Breast Cancer. Med Phys 2016. [DOI: 10.1118/1.4956287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
35
|
Langner U, Langen K. SU-F-T-161: The Effect of Pencil Beam Scanning Gantry Angle Dependent Spot Size Variations On Plan Quality. Med Phys 2016. [DOI: 10.1118/1.4956297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
36
|
Polf J, Chung H, Langen K. SU-F-T-220: Validation of Hounsfield Unit-To-Stopping Power Ratio Calibration Used for Dose Calculation in Proton Radiotherapy. Med Phys 2016. [DOI: 10.1118/1.4956359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
37
|
Zhu M, Yam M, Mehta M, Badiyan S, Young K, Malyapa R, Regine W, Langen K. SU-F-T-188: A Robust Treatment Planning Technique for Proton Pencil Beam Scanning Cranial Spinal Irradiation. Med Phys 2016. [DOI: 10.1118/1.4956325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
38
|
Yu J, Strauss D, Langner U, Langen K. SU-F-T-170: Patient Surface Dose Measurements Using Optically Stimulated Luminescence Dosimeters in Scanning Proton Beam Therapy for Breast Cancer. Med Phys 2016. [DOI: 10.1118/1.4956307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
39
|
Chen S, Guerrero M, Zhang B, Yi B, Mossahebi S, Prado K, D'Souza W, Langen K. SU-G-TeP4-11: Implementation of a Non-Measurement-Based Patient-Specific IMRT QA Program. Med Phys 2016. [DOI: 10.1118/1.4957136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
40
|
Klein EE, El Naqa I, Langen K, Dogan N. Physics: The Use of Magnetic Resonance Imaging for Radiation Therapy is Accelerating in Utility and Novelty. Int J Radiat Oncol Biol Phys 2015; 93:953-6. [PMID: 26581131 DOI: 10.1016/j.ijrobp.2015.07.2276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 07/20/2015] [Indexed: 11/24/2022]
|
41
|
Affiliation(s)
- Katja Langen
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland.
| | - Minesh Mehta
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland
| |
Collapse
|
42
|
Eley J, Mehta M, Molitoris J, Langner U, Langen K. SU-E-T-626: Practical Method to Implement Arc Therapy Using Scanned Particle Beams. Med Phys 2015. [DOI: 10.1118/1.4924989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
43
|
Xu H, Guerrero M, Yang X, Chen S, Langen K, Prado K, Schinkel C. SU-E-T-182: Clinical Implementation of TG71-Based Electron MU Calculation and Comparison with a Commercial Secondary Calculation. Med Phys 2015. [DOI: 10.1118/1.4924543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
44
|
Langen K, Guerrero M, Killefer M, Xu H, Zhou J, Zhang B, Chen S. SU-E-T-192: Commissioning of a Commercial 3D Dose Calculation Program. Med Phys 2015. [DOI: 10.1118/1.4924553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
45
|
Zhou J, Lasio G, Yi B, Huang J, Chen S, Zhang B, Langen K, Prado K, D'souza W. SU-E-J-122: The CBCT Dose Calculation Using a Patient Specific CBCT Number to Mass Density Conversion Curve Based On a Novel Image Registration and Organ Mapping Method in Head-And-Neck Radiation Therapy. Med Phys 2015. [DOI: 10.1118/1.4924208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
46
|
Chuong MD, Mehta MP, Langen K, Regine WF. Is proton beam therapy better than standard radiation therapy? The available evidence points to benefits of proton beam therapy. Clin Adv Hematol Oncol 2014; 12:861-864. [PMID: 25674846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
| | - Minesh P Mehta
- University of Maryland School of Medicine, Baltimore, MD
| | - Katja Langen
- University of Maryland School of Medicine, Baltimore, MD
| | | |
Collapse
|
47
|
Kebir S, Schafer N, Mack F, Schaub C, Niessen M, Stoffels G, Galldiks N, Langen K, Glas M, Herrlinger U. P16.17 * F-18-FET PET IMAGING FOR DIAGNOSIS OF LATE PSEUDOPROGRESSION IN PATIENTS WITH HIGH-GRADE GLIOMAS. Neuro Oncol 2014. [DOI: 10.1093/neuonc/nou174.313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
48
|
Galldiks N, Ruge MI, Hamisch C, Stoffels G, Ceccon G, Rapp M, Sabel M, Langen K. O7.05 * DIFFERENTIATION OF LOCAL RECURRENT BRAIN METASTASIS FROM RADIATION-INDUCED CHANGES USING O-(2-[18F]FLUOROETHYL)-L-TYROSINE PET. Neuro Oncol 2014. [DOI: 10.1093/neuonc/nou174.56] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
49
|
Galldiks N, Dunkl V, Stoffels G, Hutterer M, Rapp M, Kebir S, Goldbrunner R, Ruge MI, Schmidt M, Langen K. P16.10 * DIAGNOSIS OF PSEUDOPROGRESSION IN PATIENTS WITH GLIOBLASTOMA USING AMINO ACID PET. Neuro Oncol 2014. [DOI: 10.1093/neuonc/nou174.306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
50
|
Cornelius J, Stoffels G, Filss C, Galldiks N, Slotty P, Kamp M, Hänggi D, Sabel M, Steiger H, Langen K. Diagnostic Potential of O-(2-18F-fluoroethyl)-L-tyrosine PET in Patients with Meningioma. Skull Base Surg 2014. [DOI: 10.1055/s-0034-1384135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|