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Basler L, Poel R, Schröder C, Bolsi A, Lomax A, Tanadini-Lang S, Guckenberger M, Weber DC. Dosimetric analysis of local failures in skull-base chordoma and chondrosarcoma following pencil beam scanning proton therapy. Radiat Oncol 2020; 15:266. [PMID: 33198810 PMCID: PMC7670611 DOI: 10.1186/s13014-020-01711-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/06/2020] [Indexed: 12/04/2022] Open
Abstract
Background Despite combined modality treatment involving surgery and radiotherapy, a relevant proportion of skull-base chordoma and chondrosarcoma patients develop a local recurrence (LR). This study aims to analyze patterns of recurrence and correlate LR with a detailed dosimetric analysis. Methods 222 patients were treated with proton radiotherapy for chordoma (n = 151) and chondrosarcoma (n = 71) at the PSI between 1998 and 2012. All patients underwent surgery, followed by pencil-beam scanning proton therapy to a mean dose of 72.5 ± 2.2GyRBE. A retrospective patterns of recurrence analysis was performed: LR were contoured on follow-up MRI, registered with planning-imaging and the overlap with initial target structures (GTV, PTVhigh-dose, PTVlow-dose) was calculated. DVH parameters of planning structures and recurrences were calculated and correlated with LR using univariate and multivariate cox regression. Results After a median follow-up of 50 months, 35 (16%) LR were observed. Follow-up MRI imaging was available for 27 (77%) of these recurring patients. Only one (3.7%) recurrence was located completely outside the initial PTV (surgical pathway recurrence). The mean proportions of LR covered by the initial target structures were 48% (range 0–86%) for the GTV, 70% (range 0–100%) for PTVhigh and 83% (range 0–100%) for PTVlow. In the univariate analysis, the following DVH parameters were significantly associated with LR: GTV(V < 66GyRBE, p = 0.01), GTV(volume, p = 0.02), PTVhigh(max, p = 0.02), PTVhigh(V < 66GyRBE, p = 0.03), PTVhigh(V < 59GyRBE, p = 0.02), PTVhigh(volume, p = 0.01) and GTV(D95, p = 0.05). In the multivariate analysis, only histology (chordoma vs. chondrosarcoma, p = 0.01), PTVhigh(volume, p = 0.05) and GTV(V < 66GyRBE, p = 0.02) were independent prognostic factors for LR. Conclusion This study identified DVH parameters, which are associated with the risk of local recurrence after proton therapy using pencil-beam scanning for patients with skull-base chordoma and chondrosarcoma.
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De Angelis C, Albertini F, Weber D, Walser M, Lomax A, Bolsi A. OC-0702: Is there a correlation between robustness and tumor control for skull base proton PBS treatments? Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)00724-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Basler L, Schanne D, Schroeder C, De Angelis C, Hrbacek J, Lomax A, Balermpas P, Weber D. Induced Leukopenia In Head And Neck Cancer Patients Treated With Proton Or Photon Radiotherapy. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Colvill E, Safai S, Bieri O, Kozerke S, Weber D, Lomax A, Fattori G. PO-1687: Regional lung motion amplitude and variability assessment from a 4DMRI dataset. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)01705-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Colvill E, Krieger M, Bosshard P, Steinacher P, Rohrer Schnidrig BA, Parkel T, Stergiou I, Zhang Y, Peroni M, Safai S, Weber DC, Lomax A, Fattori G. Anthropomorphic phantom for deformable lung and liver CT and MR imaging for radiotherapy. Phys Med Biol 2020; 65:07NT02. [PMID: 32045898 DOI: 10.1088/1361-6560/ab7508] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this study, a functioning and ventilated anthropomorphic phantom was further enhanced for the purpose of CT and MR imaging of the lung and liver. A deformable lung, including respiratory tract was 3D printed. Within the lung's inner structures is a solid region shaped from a patient's lung tumour and six nitro-glycerine capsules as reference landmarks. The full internal mesh was coated, and the tumour filled, with polyorganosiloxane based gel. A moulded liver was created with an external casing of silicon filled with polyorganosiloxane gel and flexible plastic internal structures. The liver, fitted to the inferior portion of the right lung, moves along with the lung's ventilation. In the contralateral side, a cavity is designed to host a dosimeter, whose motion is correlated to the lung pressure. A 4DCT of the phantom was performed along with static and 4D T1 weighted MR images. The CT Hounsfield units (HU) for the flexible 3D printed material were -600-100 HU (lung and liver structures), for the polyorganosiloxane gel 30-120 HU (lung coating and liver filling) and for the silicon 650-800 HU (liver casing). The MR image intensity units were 0-40, 210-280 and 80-130, respectively. The maximum range of motion in the 4D imaging for the superior lung was 1-3.5 mm and 3.5-8 mm in the inferior portion. The liver motion was 5.5-8.0 mm at the tip and 5.7-10.0 mm at the dome. No measurable drift in motion was observed over a 2 h session and motion was reproducible over three different sessions for sin2(t), sin4(t) and a patient-like breathing curve with the interquartile range of amplitudes for all breathing cycles within 0.5 mm. The addition of features within the lung and of a deformable liver will allow the phantom to be used for imaging studies such as validation of 4DMRI and pseudo CT methods.
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Via R, Hennings F, Fattori G, Pica A, Lomax A, Weber DC, Baroni G, Hrbacek J. Technical Note: Benchmarking automated eye tracking and human detection for motion monitoring in ocular proton therapy. Med Phys 2020; 47:2237-2241. [PMID: 32037578 DOI: 10.1002/mp.14087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/17/2020] [Accepted: 02/03/2020] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Ocular proton therapy is an effective therapeutic option for patients affected with uveal melanomas. An optical eye-tracking system (ETS) aiming at noninvasive motion monitoring was developed and tested in a clinical scenario. MATERIALS AND METHODS The ETS estimates eye position and orientation at 25 frames per second using the three-dimensional position of pupil and cornea curvature centers identified, in the treatment room, through stereoscopic optical imaging and infrared eye illumination. Its capabilities for automatic detection of eye motion were retrospectively evaluated on 60 treatment fractions. Then, the ETS performance was benchmarked against the clinical standard based on visual control and manual beam interruption. RESULTS Eye-tracking system detected eye position successfully in 97% of all available frames. Eye-tracking system-based eye monitoring during therapy guarantees quicker response to involuntary eye motions than manual beam interruptions and avoids unnecessary beam interruptions. CONCLUSIONS Eye-tracking system shows promise for on-line monitoring of eye motion. Its introduction in the clinical workflow will guarantee a swifter treatment course for the patient and the clinical personnel.
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Albertini F, Matter M, Nenoff L, Zhang Y, Lomax A. Online daily adaptive proton therapy. Br J Radiol 2020; 93:20190594. [PMID: 31647313 PMCID: PMC7066958 DOI: 10.1259/bjr.20190594] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/15/2019] [Accepted: 10/22/2019] [Indexed: 12/11/2022] Open
Abstract
It is recognized that the use of a single plan calculated on an image acquired some time before the treatment is generally insufficient to accurately represent the daily dose to the target and to the organs at risk. This is particularly true for protons, due to the physical finite range. Although this characteristic enables the generation of steep dose gradients, which is essential for highly conformal radiotherapy, it also tightens the dependency of the delivered dose to the range accuracy. In particular, the use of an outdated patient anatomy is one of the most significant sources of range inaccuracy, thus affecting the quality of the planned dose distribution. A plan should be ideally adapted as soon as anatomical variations occur, ideally online. In this review, we describe in detail the different steps of the adaptive workflow and discuss the challenges and corresponding state-of-the art developments in particular for an online adaptive strategy.
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Dominietto M, Kole A, Pica A, Ahlhelm F, Lomax A, Safai S, Weber D. Deep Learning Based on Radiomics Features Dataset to Predict the Outcome of Skull-Base Chordomas Patients Treated with Pencil Beam Scanning Proton Therapy. Int J Radiat Oncol Biol Phys 2019. [DOI: 10.1016/j.ijrobp.2019.06.2168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Winterhalter C, Meier G, Oxley D, Weber D, Lomax A, Safai S. PO-0931 Application of a thin, energy-layer specific multi-leaf collimator for proton pencil beam scanning. Radiother Oncol 2019. [DOI: 10.1016/s0167-8140(19)31351-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Winterhalter C, Zepter S, Shim S, Meier G, Bolsi A, Fredh A, Hrbacek J, Oxley D, Zhang Y, Weber DC, Lomax A, Safai S. Evaluation of the ray-casting analytical algorithm for pencil beam scanning proton therapy. Phys Med Biol 2019; 64:065021. [PMID: 30641496 DOI: 10.1088/1361-6560/aafe58] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
For pencil beam scanned (PBS) proton therapy, analytical dose calculation engines are still typically used for the optimisation process, and often for the final evaluation of the plan. Recently however, the suitability of analytical calculations for planning PBS treatments has been questioned. Conceptually, the two main approaches for these analytical dose calculations are the ray-casting (RC) and the pencil-beam (PB) method. In this study, we compare dose distributions and dosimetric indices, calculated on both the clinical dose calculation grid and as a function of dose grid resolution, to Monte Carlo (MC) calculations. The analysis is done using a comprehensive set of clinical plans which represent a wide choice of treatment sites. When analysing dose difference histograms for relative treatment plans, pencil beam calculations with double grid resolution perform best, with on average 97.7%/91.9% (RC), 97.9%/92.7% (RC, double grid resolution), 97.6%/91.0% (PB) and 98.6%/94.0% (PB, double grid resolution) of voxels agreeing within ±5%/± 3% between the analytical and the MC calculations. Even though these point-to-point dose comparison shows differences between analytical and MC calculations, for all algorithms, clinically relevant dosimetric indices agree within ±4% for the PTV and within ±5% for critical organs. While the clinical agreement depends on the treatment site, there is no substantial difference of indices between the different algorithms. The pencil-beam approach however comes at a higher computational cost than the ray-casting calculation. In conclusion, we would recommend using the ray-casting algorithm for fast dose optimization and subsequently combine it with one MC calculation to scale the absolute dose and assure the quality of the treatment plan.
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Pelak M, Walser M, Bachtiary B, Bolsi A, Hrbacek J, Lomax A, Kliebsch U, Pica A, Weber D. PO-162 Patient outcome of pencil beam-scanning proton therapy in Head and Neck adenoid cystic carcinoma. Radiother Oncol 2019. [DOI: 10.1016/s0167-8140(19)30328-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Lomax A. What will the medical physics of proton therapy look like 10 yr from now? A personal view. Med Phys 2018; 45:e984-e993. [DOI: 10.1002/mp.13206] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 07/29/2018] [Accepted: 08/31/2018] [Indexed: 11/06/2022] Open
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Winterhalter C, Fura E, Tian Y, Aitkenhead A, Bolsi A, Dieterle M, Fredh A, Meier G, Oxley D, Siewert D, Weber DC, Lomax A, Safai S. Validating a Monte Carlo approach to absolute dose quality assurance for proton pencil beam scanning. ACTA ACUST UNITED AC 2018; 63:175001. [DOI: 10.1088/1361-6560/aad3ae] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Fredh A, Comiskey P, Dillon S, Mayor A, Weber DC, Lomax A. [P158] Analysis of different overlap of patched spot scanned proton fields. Phys Med 2018. [DOI: 10.1016/j.ejmp.2018.06.460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Klimpki G, Zhang Y, Fattori G, Psoroulas S, Weber DC, Lomax A, Meer D. The impact of pencil beam scanning techniques on the effectiveness and efficiency of rescanning moving targets. ACTA ACUST UNITED AC 2018; 63:145006. [DOI: 10.1088/1361-6560/aacd27] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Géli L, Henry P, Grall C, Tary JB, Lomax A, Batsi E, Riboulot V, Cros E, Gürbüz C, Işık SE, Sengör AMC, Le Pichon X, Ruffine L, Dupré S, Thomas Y, Kalafat D, Bayrakci G, Coutellier Q, Regnier T, Westbrook G, Saritas H, Çifçi G, Çağatay MN, Özeren MS, Görür N, Tryon M, Bohnhoff M, Gasperini L, Klingelhoefer F, Scalabrin C, Augustin JM, Embriaco D, Marinaro G, Frugoni F, Monna S, Etiope G, Favali P, Bécel A. Gas and seismicity within the Istanbul seismic gap. Sci Rep 2018; 8:6819. [PMID: 29717139 PMCID: PMC5931589 DOI: 10.1038/s41598-018-23536-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/06/2018] [Indexed: 11/13/2022] Open
Abstract
Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the “Istanbul seismic gap”) has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5–5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M < 3) within the Istanbul offshore domain.
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Snider JW, Schneider RA, Poelma-Tap D, Stieb S, Murray FR, Placidi L, Albertini F, Lomax A, Bolsi A, Kliebsch U, Malyapa R, Weber DC. Long-Term Outcomes and Prognostic Factors After Pencil-Beam Scanning Proton Radiation Therapy for Spinal Chordomas: A Large, Single-Institution Cohort. Int J Radiat Oncol Biol Phys 2018; 101:226-233. [DOI: 10.1016/j.ijrobp.2018.01.060] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/22/2017] [Accepted: 01/16/2018] [Indexed: 01/24/2023]
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Delaney A, Dong L, Mascia A, Zou W, Zhang Y, Yin L, Hrbacek J, Lomax A, Slotman B, Dahele M, Verbakel W. OC-0304: Using a single knowledge-based proton planning model to create automated plans for different centers. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)30614-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Fredh A, Winterhalter C, Fura E, Bolsi A, Safai S, Weber D, Lomax A. EP-1815: Comparison of independent Monte Carlo calculations with measurements of spot scanned proton fields. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)32124-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Rosas S, Belosi M, Bizzocchi N, Morach P, Zepter S, Weber D, Lomax A, Hrbacek J. EP-2186: An analysis of the clinical performance of Eclipse for PBS proton therapy treatment planning. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)32495-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Placidi L, Pica A, Ahllhelm F, Walser M, Lomax A, Bolsi A, Weber D. EP-1958: LET evaluation for pediatric craniopharyngioma with cerebral vasculopathies after PBS proton therapy. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)32267-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Via R, Hennings F, Fattori G, Fassi A, Pica A, Lomax A, Weber DC, Baroni G, Hrbacek J. Noninvasive eye localization in ocular proton therapy through optical eye tracking: A proof of concept. Med Phys 2018; 45:2186-2194. [DOI: 10.1002/mp.12841] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/16/2018] [Accepted: 02/17/2018] [Indexed: 11/05/2022] Open
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Winterhalter C, Lomax A, Oxley D, Weber DC, Safai S. A study of lateral fall-off (penumbra) optimisation for pencil beam scanning (PBS) proton therapy. Phys Med Biol 2018; 63:025022. [PMID: 29324441 DOI: 10.1088/1361-6560/aaa2ad] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The lateral fall-off is crucial for sparing organs at risk in proton therapy. It is therefore of high importance to minimize the penumbra for pencil beam scanning (PBS). Three optimisation approaches are investigated: edge-collimated uniformly weighted spots (collimation), pencil beam optimisation of uncollimated pencil beams (edge-enhancement) and the optimisation of edge collimated pencil beams (collimated edge-enhancement). To deliver energies below 70 MeV, these strategies are evaluated in combination with the following pre-absorber methods: field specific fixed thickness pre-absorption (fixed), range specific, fixed thickness pre-absorption (automatic) and range specific, variable thickness pre-absorption (variable). All techniques are evaluated by Monte Carlo simulated square fields in a water tank. For a typical air gap of 10 cm, without pre-absorber collimation reduces the penumbra only for water equivalent ranges between 4-11 cm by up to 2.2 mm. The sharpest lateral fall-off is achieved through collimated edge-enhancement, which lowers the penumbra down to 2.8 mm. When using a pre-absorber, the sharpest fall-offs are obtained when combining collimated edge-enhancement with a variable pre-absorber. For edge-enhancement and large air gaps, it is crucial to minimize the amount of material in the beam. For small air gaps however, the superior phase space of higher energetic beams can be employed when more material is used. In conclusion, collimated edge-enhancement combined with the variable pre-absorber is the recommended setting to minimize the lateral penumbra for PBS. Without collimator, it would be favourable to use a variable pre-absorber for large air gaps and an automatic pre-absorber for small air gaps.
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Klimpki G, Psoroulas S, Bula C, Rechsteiner U, Eichin M, Weber DC, Lomax A, Meer D. A beam monitoring and validation system for continuous line scanning in proton therapy. ACTA ACUST UNITED AC 2017; 62:6126-6143. [DOI: 10.1088/1361-6560/aa772e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Belosi M, Van der Meer R, Garcia de Acilu Laa P, Bolsi A, Weber D, Lomax A. OC-0230: Treatment log files as a tool to identify inaccuracies in scanned proton beam delivery and planning. Radiother Oncol 2017. [DOI: 10.1016/s0167-8140(17)30673-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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