1
|
Solov'yov AV, Verkhovtsev AV, Mason NJ, Amos RA, Bald I, Baldacchino G, Dromey B, Falk M, Fedor J, Gerhards L, Hausmann M, Hildenbrand G, Hrabovský M, Kadlec S, Kočišek J, Lépine F, Ming S, Nisbet A, Ricketts K, Sala L, Schlathölter T, Wheatley AEH, Solov'yov IA. Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment. Chem Rev 2024. [PMID: 38842266 DOI: 10.1021/acs.chemrev.3c00902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
This roadmap reviews the new, highly interdisciplinary research field studying the behavior of condensed matter systems exposed to radiation. The Review highlights several recent advances in the field and provides a roadmap for the development of the field over the next decade. Condensed matter systems exposed to radiation can be inorganic, organic, or biological, finite or infinite, composed of different molecular species or materials, exist in different phases, and operate under different thermodynamic conditions. Many of the key phenomena related to the behavior of irradiated systems are very similar and can be understood based on the same fundamental theoretical principles and computational approaches. The multiscale nature of such phenomena requires the quantitative description of the radiation-induced effects occurring at different spatial and temporal scales, ranging from the atomic to the macroscopic, and the interlinks between such descriptions. The multiscale nature of the effects and the similarity of their manifestation in systems of different origins necessarily bring together different disciplines, such as physics, chemistry, biology, materials science, nanoscience, and biomedical research, demonstrating the numerous interlinks and commonalities between them. This research field is highly relevant to many novel and emerging technologies and medical applications.
Collapse
Affiliation(s)
- Andrey V Solov'yov
- MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main, Germany
| | | | - Nigel J Mason
- School of Physics and Astronomy, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - Richard A Amos
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, U.K
| | - Ilko Bald
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Gérard Baldacchino
- Université Paris-Saclay, CEA, LIDYL, 91191 Gif-sur-Yvette, France
- CY Cergy Paris Université, CEA, LIDYL, 91191 Gif-sur-Yvette, France
| | - Brendan Dromey
- Centre for Light Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| | - Martin Falk
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61200 Brno, Czech Republic
- Kirchhoff-Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Juraj Fedor
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Luca Gerhards
- Institute of Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Michael Hausmann
- Kirchhoff-Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Georg Hildenbrand
- Kirchhoff-Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
- Faculty of Engineering, University of Applied Sciences Aschaffenburg, Würzburger Str. 45, 63743 Aschaffenburg, Germany
| | | | - Stanislav Kadlec
- Eaton European Innovation Center, Bořivojova 2380, 25263 Roztoky, Czech Republic
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Franck Lépine
- Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Villeurbanne, France
| | - Siyi Ming
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Andrew Nisbet
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, U.K
| | - Kate Ricketts
- Department of Targeted Intervention, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Leo Sala
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Thomas Schlathölter
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- University College Groningen, University of Groningen, Hoendiepskade 23/24, 9718 BG Groningen, The Netherlands
| | - Andrew E H Wheatley
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Ilia A Solov'yov
- Institute of Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| |
Collapse
|
2
|
Shaikh S, Escribano-Rodriguez S, Radogna R, Kelleter L, Godden C, Warren M, Attree D, Saakyan R, Mortimer L, Corlett P, Warry A, Gosling A, Baker C, Poynter A, Kacperek A, Jolly S. Spread-out Bragg peak measurements using a compact quality assurance range calorimeter at the Clatterbridge cancer centre. Phys Med Biol 2024; 69:115015. [PMID: 38657625 DOI: 10.1088/1361-6560/ad42fd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
Objective.The superior dose conformity provided by proton therapy relative to conventional x-ray radiotherapy necessitates more rigorous quality assurance (QA) procedures to ensure optimal patient safety. Practically however, time-constraints prevent comprehensive measurements to be made of the proton range in water: a key parameter in ensuring accurate treatment delivery.Approach.A novel scintillator-based device for fast, accurate water-equivalent proton range QA measurements for ocular proton therapy is presented. Experiments were conducted using a compact detector prototype, the quality assurance range calorimeter (QuARC), at the Clatterbridge cancer centre (CCC) in Wirral, UK for the measurement of pristine and spread-out Bragg peaks (SOBPs). The QuARC uses a series of 14 optically-isolated 100 × 100 × 2.85 mm polystyrene scintillator sheets, read out by a series of photodiodes. The detector system is housed in a custom 3D-printed enclosure mounted directly to the nozzle and a numerical model was used to fit measured depth-light curves and correct for scintillator light quenching.Main results.Measurements of the pristine 60 MeV proton Bragg curve found the QuARC able to measure proton ranges accurate to 0.2 mm and reduced QA measurement times from several minutes down to a few seconds. A new framework of the quenching model was deployed to successfully fit depth-light curves of SOBPs with similar range accuracy.Significance.The speed, range accuracy and simplicity of the QuARC make the device a promising candidate for ocular proton range QA. Further work to investigate the performance of SOBP fitting at higher energies/greater depths is warranted.
Collapse
Affiliation(s)
- Saad Shaikh
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | | | | | - Laurent Kelleter
- Division of Medical Physics in Radiation Oncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Connor Godden
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Matthew Warren
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Derek Attree
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Ruben Saakyan
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Linda Mortimer
- Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
| | - Peter Corlett
- Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
| | - Alison Warry
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrew Gosling
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Colin Baker
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrew Poynter
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrzej Kacperek
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Simon Jolly
- Department of Physics and Astronomy, University College London, London, United Kingdom
| |
Collapse
|
3
|
Tjelta J, Fjæra LF, Ytre-Hauge KS, Boer CG, Stokkevåg CH. A systematic approach for calibrating a Monte Carlo code to a treatment planning system for obtaining dose, LET, variable proton RBE and out-of-field dose. Phys Med Biol 2023; 68:225010. [PMID: 37820690 DOI: 10.1088/1361-6560/ad0281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 10/11/2023] [Indexed: 10/13/2023]
Abstract
Objective. While integration of variable relative biological effectiveness (RBE) has not reached full clinical implementation, the importance of having the ability to recalculate proton treatment plans in a flexible, dedicated Monte Carlo (MC) code cannot be understated . Here we provide a step-wise method for calibrating dose from a MC code to a treatment planning system (TPS), to obtain required parameters for calculating linear energy transfer (LET), variable RBE and in general enabling clinical realistic research studies beyond the capabilities of a TPS.Approach. Initially, Pristine Bragg peaks (PBP) were calculated in both the Eclipse TPS and the FLUKA MC code. A rearranged Bortfeld energy-range relation was applied to the initial energy of the beam to fine-tune the range of the MC code at 80% dose level distal to the PBP. The energy spread was adapted by dividing the TPS range by the MC range for dose level 80%-20% distal to the PBP. Density and relative proton stopping power were adjusted by comparing the TPS and MC for different Hounsfield units. To find the relationship of dose per primary particle from the MC to dose per monitor unit in the TPS, integration was applied to the area of the Bragg curve. The calibration was validated for spread-out Bragg peaks (SOBP) in water and patient treatment plans. Following the validation, variable RBE were calculated using established models.Main results.The PBPs ranges were within ±0.3mm threshold, and a maximum of 5.5% difference for the SOBPs was observed. The patient validation showed excellent dose agreement between the TPS and MC, with the greatest differences for the lung tumor patient.Significance. Aprocedure for calibrating a MC code to a TPS was developed and validated. The procedure enables MC-based calculation of dose, LET, variable RBE, advanced (secondary) particle tracking and more from treatment plans.
Collapse
Affiliation(s)
- Johannes Tjelta
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Lars Fredrik Fjæra
- Department of Physics and Technology, University of Bergen, Bergen, Norway
- Department of Oncology and Medical Physics, Oslo University Hospital, Oslo, Norway
| | | | | | - Camilla Hanquist Stokkevåg
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| |
Collapse
|
4
|
van Marlen P, van de Water S, Dahele M, Slotman BJ, Verbakel WFAR. Single Ultra-High Dose Rate Proton Transmission Beam for Whole Breast FLASH-Irradiation: Quantification of FLASH-Dose and Relation with Beam Parameters. Cancers (Basel) 2023; 15:cancers15092579. [PMID: 37174045 PMCID: PMC10177419 DOI: 10.3390/cancers15092579] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/25/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
Healthy tissue-sparing effects of FLASH (≥40 Gy/s, ≥4-8 Gy/fraction) radiotherapy (RT) make it potentially useful for whole breast irradiation (WBI), since there is often a lot of normal tissue within the planning target volume (PTV). We investigated WBI plan quality and determined FLASH-dose for various machine settings using ultra-high dose rate (UHDR) proton transmission beams (TBs). While five-fraction WBI is commonplace, a potential FLASH-effect might facilitate shorter treatments, so hypothetical 2- and 1-fraction schedules were also analyzed. Using one tangential 250 MeV TB delivering 5 × 5.7 Gy, 2 × 9.74 Gy or 1 × 14.32 Gy, we evaluated: (1) spots with equal monitor units (MUs) in a uniform square grid with variable spacing; (2) spot MUs optimized with a minimum MU-threshold; and (3) splitting the optimized TB into two sub-beams: one delivering spots above an MU-threshold, i.e., at UHDRs; the other delivering the remaining spots necessary to improve plan quality. Scenarios 1-3 were planned for a test case, and scenario 3 was also planned for three other patients. Dose rates were calculated using the pencil beam scanning dose rate and the sliding-window dose rate. Various machine parameters were considered: minimum spot irradiation time (minST): 2 ms/1 ms/0.5 ms; maximum nozzle current (maxN): 200 nA/400 nA/800 nA; two gantry-current (GC) techniques: energy-layer and spot-based. For the test case (PTV = 819 cc) we found: (1) a 7 mm grid achieved the best balance between plan quality and FLASH-dose for equal-MU spots; (2) near the target boundary, lower-MU spots are necessary for homogeneity but decrease FLASH-dose; (3) the non-split beam achieved >95% FLASH for favorable (not clinically available) machine parameters (SB GC, low minST, high maxN), but <5% for clinically available settings (EB GC, minST = 2 ms, maxN = 200 nA); and (4) splitting gave better plan quality and higher FLASH-dose (~50%) for available settings. The clinical cases achieved ~50% (PTV = 1047 cc) or >95% (PTV = 477/677 cc) FLASH after splitting. A single UHDR-TB for WBI can achieve acceptable plan quality. Current machine parameters limit FLASH-dose, which can be partially overcome using beam-splitting. WBI FLASH-RT is technically feasible.
Collapse
Affiliation(s)
- Patricia van Marlen
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
| | - Steven van de Water
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
| | - Max Dahele
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
| | - Berend J Slotman
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
| | - Wilko F A R Verbakel
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
| |
Collapse
|
5
|
Zhang J, Liang Y, Yang C. Proton beam secondary depth-dose calculation with a secondary propagation model. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
|
6
|
Vedelago J, Karger CP, Jäkel O. A review on reference dosimetry in radiation therapy with proton and light ion beams: status and impact of new developments. RADIAT MEAS 2022. [DOI: 10.1016/j.radmeas.2022.106844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
|
7
|
Wang M, Zhang L, Zheng J, Li G, Dai W, Dong L. Investigating the effects of a range shifter on skin dose in proton therapy. NUCLEAR ENGINEERING AND TECHNOLOGY 2022. [DOI: 10.1016/j.net.2022.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
8
|
Qi Y, Mao L, Lu H, Jin S, Huang J, Wang Z, Zhang J, Wang K. Multi-centric analysis of linear energy transfer distribution from clinical proton beam based on TOPAS. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
9
|
Kern A, Bäumer C, Kröninger K, Wulff J, Timmermann B. Impact of air gap, range shifter, and delivery technique on skin dose in proton therapy. Med Phys 2020; 48:831-840. [PMID: 33368345 DOI: 10.1002/mp.14626] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVE Side effects of radiation therapy may include skin damage. The surface dose is of great interest and contains the buildup effect. In particular, the proton therapy community requires further experimental data to quantify doses in the surface region. This specification includes the skin dose, which is defined according to ICRU Report No. 39 at 70 μm water equivalent depth. The aim of this study is to gather more knowledge of the skin dose by varying key parameters defined by the patient treatment plan. This consists of clinical aspects such as the influence of the air gap, the application of a range shifter (RS), or the proton delivery technique. MATERIAL/METHODS Skin doses were determined with a PTW 23391 extrapolation chamber with three thin Kapton® entrance windows operated as a conventional ionization chamber. The impact on the skin dose for quasi-monoenergetic pencil beam scanning (PBS) proton beams was evaluated for clinical air gaps between 3.5 and 51.1 cm. The differences in skin dose were assessed by irradiating equivalent fields with an RS of 51 mm water equivalent thickness (RS51) and without. Furthermore, the delivery techniques PBS, uniform scanning (US), and double scattering (DS) were compared by defining a spread-out Bragg peak (SOBP). TOPAS (V.3.1.2) was used to model an IBA nozzle with PBS and to score dose to water at the surface of a water phantom. RESULTS For the monoenergetic fields without the application of the RS the skin dose was constant down to an air gap of 6.2 cm. A lower air gap of 3.5 cm showed a variation in skin dose by up to 2.4% compared to the results obtained with larger air gaps. With the inserted RS51 an increase in the skin dose was found for air gaps smaller than 11.3 cm. Experimentally, a dose difference of 1.4% was recorded for an air gap of 6.2 cm by inserting an RS and none. With the Monte Carlo calculations the largest dose increase was observed at the air gap of 3.5 cm with 1.7% and 4.0% relative to the skin dose results without the RS and to the largest evaluated air gap of 51.1 cm, respectively. The SOBP comparison of the beam modalities at the measuring plane at the isocenter revealed higher skin doses without RS (including RS) by up to +1.9% (+1.5%) for DS and +1.3% (+1.1%) for US compared to PBS. For all three techniques an approx. 2% rise in skin dose was observed for the largest evaluated air gap of 37.7 cm to an air gap of 6.2 cm when using an RS51. CONCLUSION The study investigated aspects of skin dose of a water equivalent phantom by varying key parameters of a proton treatment plan. Parameters like the RS, the air gap, and the delivery modality have an impact on the order of 4.0% for the skin dose at the depth of 70 μm. The increases in skin dose are the effects of the contribution of the increased electron fluence at small air gaps and the emitted hadronic particles produced by the RS.
Collapse
Affiliation(s)
- A Kern
- West German Proton Therapy Centre Essen (WPE), Essen, 45147, Germany.,University Hospital Essen, Essen, 45147, Germany.,Faculty of Physics, TU Dortmund University, Dortmund, 44227, Germany.,West German Cancer Center (WTZ), Essen, 45147, Germany
| | - C Bäumer
- West German Proton Therapy Centre Essen (WPE), Essen, 45147, Germany.,University Hospital Essen, Essen, 45147, Germany.,West German Cancer Center (WTZ), Essen, 45147, Germany.,German Cancer Consortium (DKTK), Heidelberg, 69120, Germany.,Faculty of Physics, Essen, 45147, Germany
| | - K Kröninger
- Faculty of Physics, TU Dortmund University, Dortmund, 44227, Germany
| | - J Wulff
- West German Proton Therapy Centre Essen (WPE), Essen, 45147, Germany.,University Hospital Essen, Essen, 45147, Germany.,West German Cancer Center (WTZ), Essen, 45147, Germany
| | - B Timmermann
- West German Proton Therapy Centre Essen (WPE), Essen, 45147, Germany.,University Hospital Essen, Essen, 45147, Germany.,West German Cancer Center (WTZ), Essen, 45147, Germany.,German Cancer Consortium (DKTK), Heidelberg, 69120, Germany.,Clinic for Particle Therapy, Essen, 45147, Germany
| |
Collapse
|
10
|
Kelleter L, Radogna R, Volz L, Attree D, Basharina-Freshville A, Seco J, Saakyan R, Jolly S. A scintillator-based range telescope for particle therapy. Phys Med Biol 2020; 65:165001. [PMID: 32422621 DOI: 10.1088/1361-6560/ab9415] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The commissioning and operation of a particle therapy centre requires an extensive set of detectors for measuring various parameters of the treatment beam. Among the key devices are detectors for beam range quality assurance. In this work, a novel range telescope based on a plastic scintillator and read out by a large-scale CMOS sensor is presented. The detector is made of a stack of 49 plastic scintillator sheets with a thickness of 2-3 mm and an active area of 100 × 100 mm2, resulting in a total physical stack thickness of 124.2 mm. This compact design avoids optical artefacts that are common in other scintillation detectors. The range of a proton beam is reconstructed using a novel Bragg curve model that incorporates scintillator quenching effects. Measurements to characterise the performance of the detector were carried out at the Heidelberger Ionenstrahl-Therapiezentrum (HIT, Heidelberg, GER) and the Clatterbridge Cancer Centre (CCC, Bebington, UK). The maximum difference between the measured range and the reference range was found to be 0.41 mm at a proton beam range of 310 mm and was dominated by detector alignment uncertainties. With the new detector prototype, the water-equivalent thickness of PMMA degrader blocks has been reconstructed within ± 0.1 mm. An evaluation of the radiation hardness proves that the range reconstruction algorithm is robust following the deposition of 6,300 Gy peak dose into the detector. Furthermore, small variations in the beam spot size and transverse beam position are shown to have a negligible effect on the range reconstruction accuracy. The potential for range measurements of ion beams is also investigated.
Collapse
Affiliation(s)
- Laurent Kelleter
- Dept. Physics and Astronomy, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Kern A, Bäumer C, Kröninger K, Mertens L, Timmermann B, Walbersloh J, Wulff J. Determination of surface dose in pencil beam scanning proton therapy. Med Phys 2020; 47:2277-2288. [PMID: 32037577 DOI: 10.1002/mp.14086] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/03/2020] [Accepted: 02/03/2020] [Indexed: 11/11/2022] Open
Abstract
PURPOSE/OBJECTIVE Quantification of surface dose within the first few hundred water equivalent µm is challenging. Nevertheless, it is of large interest for the proton therapy community to study dose effects in the skin. The experimental determination is affected by the detector properties, such as the detector volume and material. The International Commission on Radiation Units and Measurements in its report 39 recommends assessing the skin dose at a depth of 0.07 mm. The aim of this study is the estimation of the absorbed dose at and around a depth of 70 µm. We used various dosimetric approaches in conjunction with proton pencil beam scanning delivery to determine the skin dose in a clinical setting. MATERIAL/METHODS Five different detectors were tested for determining the surface dose in water: EBT3 and HD-V2 GAFCHROMIC™ radiochromic film, LiF:Mg,Ti thermoluminescent dosimeter, IBA PPC05 plane-parallel ionization chamber, and PTW 23391 extrapolation chamber. The irradiation setup consisted of quasi-monoenergetic scanned proton pencil beams with kinetic energies of 100, 150, and 226.7 MeV, respectively. Radiochromic films were placed within a vertical stack and in wedge geometry and were analyzed with FilmQA Pro™ adopting triple channel dosimetry. The extrapolation chamber PTW 23391, which served as a reference in the current work, was used in a conventional ionization chamber setup with a fixed electrode gap of 2 mm. Three Kapton® entrance windows with thicknesses of 25, 50, and 75 µm were employed. Thermoluminescent dosimeters were provided as powder and were pressed onto a sheet of aluminum. Furthermore, the Monte Carlo code TOol for PArticle Simulation (TOPAS) in version 3.1.p2 was used to model an IBA pencil beam scanning nozzle and score dose to water in a water phantom. RESULTS The resulting depth dose curves were normalized to their 100% dose at the reference depth of 3 cm. We obtained the skin doses with the extrapolation chamber and with TOPAS. For the experimental approach this resulted in 79.7 ± 0.3%, 86.0 ± 0.6%, and 87.1 ± 0.1% for the proton energies 100, 150, and 226.7 MeV, respectively. The results for TOPAS were 80.1 ± 0.2% (100 MeV), 87.1 ± 0.5% (150 MeV), and 86.9 ± 0.4% (226.7 MeV), respectively. Based on the experimental results of the skin dose, we provided a clinically relevant surface extrapolation factor for the common measurement methods. This allows the result of the first measurement depth of a detector to be scaled to the dose at the skin depth. Most practical would be the use of the surface extrapolation factor for the PPC05 chamber, due to its direct reading, the wide availability in clinics and the low uncertainties. The calculated factors were 0.986 ± 0.004 for 100 MeV, 0.961 ± 0.008 for 150 MeV, and 0.963 ± 0.003 for 226.7 MeV. CONCLUSIONS In this study, dissimilar experimental approaches were evaluated with respect to measurements at depths close to the surface. The experimental depth dose curves are in good agreement with the simulation with TOPAS Monte Carlo. To the author's knowledge this was the first experimental determination of the skin dose according to the International Commission on Radiation Units and Measurements 39 definition in proton pencil beam scanning.
Collapse
Affiliation(s)
- A Kern
- West German Proton Therapy Center Essen (WPE), Essen, 45147, Germany.,University Hospital Essen, Essen, 45147, Germany.,Experimentelle Physik IV, TU Dortmund University, Dortmund, 44227, Germany.,West German Cancer Center (WTZ), Essen, 45147, Germany
| | - C Bäumer
- West German Proton Therapy Center Essen (WPE), Essen, 45147, Germany.,University Hospital Essen, Essen, 45147, Germany.,Experimentelle Physik IV, TU Dortmund University, Dortmund, 44227, Germany.,West German Cancer Center (WTZ), Essen, 45147, Germany.,German Cancer Consortium (DKTK), Heidelberg, 69120, Germany
| | - K Kröninger
- Experimentelle Physik IV, TU Dortmund University, Dortmund, 44227, Germany
| | - L Mertens
- University Medical Center Mannheim, University of Heidelberg, Mannheim, 68167, Germany
| | - B Timmermann
- West German Proton Therapy Center Essen (WPE), Essen, 45147, Germany.,University Hospital Essen, Essen, 45147, Germany.,West German Cancer Center (WTZ), Essen, 45147, Germany.,German Cancer Consortium (DKTK), Heidelberg, 69120, Germany.,Clinic for Particle Therapy, Essen, 45147, Germany
| | - J Walbersloh
- Materialprüfungsamt Nordrhein-Westfalen, Dortmund, 44287, Germany
| | - J Wulff
- West German Proton Therapy Center Essen (WPE), Essen, 45147, Germany.,University Hospital Essen, Essen, 45147, Germany.,West German Cancer Center (WTZ), Essen, 45147, Germany
| |
Collapse
|
12
|
Kelleter L, Jolly S. A mathematical expression for depth-light curves of therapeutic proton beams in a quenching scintillator. Med Phys 2020; 47:2300-2308. [PMID: 32072646 DOI: 10.1002/mp.14099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/21/2020] [Accepted: 02/13/2020] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Recently, there has been increasing interest in the development of scintillator-based detectors for the measurement of depth-dose curves of therapeutic proton beams (Beaulieu and Beddar [2016], Phys Med Biol., 61:R305-R343). These detectors allow the measurement of single beam parameters such as the proton range or the reconstruction of the full three-dimensional dose distribution. Thus, scintillation detectors could play an important role in beam quality assurance, online beam monitoring, and proton imaging. However, the light output of the scintillator as a function of dose deposition is subject to quenching effects due to the high-specific energy loss of incident protons, particularly in the Bragg peak. The aim of this work is to develop a model that describes the percent depth-light curve in a quenching scintillator and allow the extraction of information about the beam range and the strength of the quenching. METHODS A mathematical expression of a depth-light curve, derived from a combination of Birks' law (Birks [1951], Proc Phys Soc A., 64:874) and Bortfeld's Bragg curve (Bortfeld [1997], Med Phys., 24:2024-2033) that is termed a "quenched Bragg" curve, is presented. The model is validated against simulation and measurement. RESULTS A fit of the quenched Bragg model to simulated depth-light curves in a polystyrene-based scintillator shows good agreement between the two, with a maximum deviation of 2.5% at the Bragg peak. The differences are larger behind the Bragg peak and in the dose build-up region. In the same simulation, the difference between the reconstructed range and the reference proton range is found to be always smaller than 0.16 mm. The comparison with measured data shows that the fitted beam range agrees with the reference range within their respective uncertainties. CONCLUSIONS The quenched Bragg model is, therefore, an accurate tool for the range measurement from quenched depth-dose curves. Moreover, it allows the reconstruction of the beam energy spread, the particle fluence, and the magnitude of the quenching effect from a measured depth-light curve.
Collapse
Affiliation(s)
- Laurent Kelleter
- Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT, London, UK
| | - Simon Jolly
- Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT, London, UK
| |
Collapse
|
13
|
Pfuhl T, Horst F, Schuy C, Weber U. Comment on: “Technical note: Simulation of dose buildup in proton pencil beams” [Med Phys. 46(8): 3734–3738 (2019)]. Med Phys 2019; 46:5876-5877. [DOI: 10.1002/mp.13860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/02/2019] [Accepted: 10/07/2019] [Indexed: 11/07/2022] Open
Affiliation(s)
- Tabea Pfuhl
- GSI Helmholtzzentrum für Schwerionenforschung 64291Darmstadt Germany
- Physics Department, Technische Universität Darmstadt 64289Darmstadt Germany
| | - Felix Horst
- GSI Helmholtzzentrum für Schwerionenforschung 64291Darmstadt Germany
- Institute of Medical Physics and Radiation Protection University of Applied Sciences 35390Giessen Germany
| | - Christoph Schuy
- GSI Helmholtzzentrum für Schwerionenforschung 64291Darmstadt Germany
| | - Uli Weber
- GSI Helmholtzzentrum für Schwerionenforschung 64291Darmstadt Germany
| |
Collapse
|