1
|
Yu H, He S, He Y, Dai G, Fu Y, Zeng X, Liu M, Ai P. Dosimetric comparison of advanced radiation techniques for scalp-sparing in low-grade gliomas. Strahlenther Onkol 2024:10.1007/s00066-024-02229-3. [PMID: 38649484 DOI: 10.1007/s00066-024-02229-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/03/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND Alopecia causes significant distress for patients and negatively impacts quality of life for low-grade glioma (LGG) patients. We aimed to compare and evaluate variations in dose distribution for scalp-sparing in LGG patients with proton therapy and photon therapy, namely intensity-modulated proton therapy (IMPT), intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and helical tomotherapy (HT). METHODS This retrospective study utilized a dataset comprising imaging data from 22 patients with LGG who underwent postoperative radiotherapy. Treatment plans were generated for each patient with scalp-optimized (SO) approaches and scalp-non-optimized (SNO) approaches using proton techniques and photons techniques; all plans adhered to the same dose constraint of delivering a total radiation dose of 54.04 Gy to the target volume. All treatment plans were subsequently analyzed. RESULTS All the plans generated in this study met the dose constraints for the target volume and OARs. The SO plans resulted in reduced maximum scalp dose (Dmax), mean scalp dose (Dmean), and volume of the scalp receiving 30 Gy (V30) and 40 Gy (V40) compared with SNO plans in all radiation techniques. Among all radiation techniques, the IMPT plans exhibited superior performance compared to other plans for dose homogeneity as for SO plans. Also, IMPT showed lower values for Dmean and Dmax than all photon radiation techniques. CONCLUSION Our study provides evidence that the SO approach is a feasible technique for reducing scalp radiation dose. However, it is imperative to conduct prospective trials to assess the benefits associated with this approach.
Collapse
Affiliation(s)
- Hang Yu
- Department of Radiotherapy Physics & Technology, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan Province, China
| | - Shuangshuang He
- Department of Radiation Oncology and Department of Head and Neck Oncology, Cancer Center, West China Hospital, Sichuan University, Sichuan, China
| | - Yisong He
- Medical Physics Laboratory, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, 610072, Chengdu, China
| | - Guyu Dai
- Department of Radiotherapy Physics & Technology, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan Province, China
| | - Yuchuan Fu
- Department of Radiotherapy Physics & Technology, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan Province, China
| | - Xianhu Zeng
- Department of Radiotherapy Physics & Technology, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan Province, China
| | - Mengyuan Liu
- Department of Radiation Oncology and Department of Head and Neck Oncology, Cancer Center, West China Hospital, Sichuan University, Sichuan, China
| | - Ping Ai
- Department of Radiation Oncology and Department of Head and Neck Oncology, Cancer Center, West China Hospital, Sichuan University, Sichuan, China.
| |
Collapse
|
2
|
Wulff J, Paul A, Bäcker CM, Baumann KS, Esser JN, Koska B, Timmermann B, Verbeek NG, Bäumer C. Consistency of Faraday cup and ionization chamber dosimetry of proton fields and the role of nuclear interactions. Med Phys 2024; 51:2277-2292. [PMID: 37991110 DOI: 10.1002/mp.16819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 09/21/2023] [Accepted: 09/28/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND A Faraday cup (FC) facilitates a quite clean measurement of the proton fluence emerging from clinical spot-scanning nozzles with narrow pencil-beams. The utilization of FCs appears to be an attractive option for high dose rate delivery modes and the source models of Monte-Carlo (MC) dose engines. However, previous studies revealed discrepancies of 3%-6% between reference dosimetry with ionization chambers (ICs) and FC-based dosimetry. This has prevented the widespread use of FCs for dosimetry in proton therapy. PURPOSE The current study aims at bridging the gap between FC dosimetry and IC dosimetry of proton fields delivered with spot-scanning treatment heads. Particularly, a novel method to evaluate FC measurements is introduced. METHODS A consistency check is formulated, which makes use of the energy balance and the reciprocity theorem. The measurement data comprise central-axis depth distributions of the absorbed dose of quasi-monochromatic fields with a width of about 28.5 cm and FC measurements of the reciprocal fields with a single spot. These data are complemented by a look-up of energy-range tables, the average Q-value of transmutations, and the escape energy carried away by neutrons and photons. The latter data are computed by MC simulations, which in turn are validated with measurements of the distal dose tail and neutron out-of-field doses. For comparison, the conventional approach of FC evaluation is performed, which computes absorbed dose from the product of fluence and stopping power. The results from the FC measurements are compared with the standard dosimetry protocols and improved reference dosimetry methods. RESULTS The deviation between the conventional FC-based dosimetry and the IC-based one according to standard dosimetry protocols was -4.7 ( ± $\pm$ 3.3)% for a 100 MeV field and -3.6 ( ± $\pm$ 3.5)% for 200 MeV, thereby agreeing within the reported uncertainties. The deviations could be reduced to -4.0 ( ± $\pm$ 2.9)% and -3.0 ( ± $\pm$ 3.1)% by adopting state-of-the-art reference dosimetry methods. The alternative approach using the energy balance gave deviations of only -1.9% (100 MeV) and -2.6% (200 MeV) using state-of-the-art dosimetry. The standard uncertainty of this novel approach was estimated to be about 2%. CONCLUSIONS An alternative concept has been established to determine the absorbed dose of monoenergetic proton fields with an FC. It eliminates the strong dependence of the conventional FC-based approach on the MC simulation of the stopping-power and of the secondary ions, which according to the study at hand is the major contributor to the underestimation of the absorbed dose. Some contributions to the uncertainty of the novel approach could potentially be reduced in future studies. This would allow for accurate consistency tests of conventional dosimetry procedures.
Collapse
Affiliation(s)
- Jörg Wulff
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Anne Paul
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
- Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Claus Maximilian Bäcker
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Kilian-Simon Baumann
- Department of Radiotherapy and Radiation Oncology, Marburg University Hospital, Marburg, Germany
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Johannes Niklas Esser
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Benjamin Koska
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Beate Timmermann
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
- Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Cancer Consortium (DKTK), Essen, Germany
- Department of Particle Therapy, University Hospital Essen, Essen, Germany
| | - Nico Gerd Verbeek
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Christian Bäumer
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
- German Cancer Consortium (DKTK), Essen, Germany
- Department of Physics, Technische Universität Dortmund, Dortmund, Germany
| |
Collapse
|
3
|
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]
|
4
|
Behrends C, Bäumer C, Verbeek N, Ehlert J, Prasad R, Wulff J, Lühr A, Timmermann B. Technical note: Providing proton fields down to the few-MeV level at clinical pencil beam scanning facilities for radiobiological experiments. Med Phys 2021; 49:666-674. [PMID: 34855985 DOI: 10.1002/mp.15388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/03/2021] [Accepted: 11/18/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The adequate performance of radiobiological experiments using clinical proton beams typically requires substantial preparations to provide the appropriate setup for specific experiments. Providing radiobiologically interesting low-energy protons is a particular challenge, due to various physical effects that become more pronounced with larger absorber thickness and smaller proton energy. This work demonstrates the generation of decelerated low-energy protons from a clinical proton beam. METHODS Monte Carlo simulations of proton energy spectra were performed for energy absorbers with varying thicknesses to reduce the energy of the clinical proton beam down to the few-MeV level corresponding to μ m-ranges. In this way, a setup with an optimum thickness of the absorber with a maximum efficiency of the proton fluence for the provisioning of low-energy protons is supposed to be found. For the specific applications of 2.5-3.3 MeV protons and α -particle range equivalent protons, the relative depth dose was measured and simulated together with the dose-averaged linear energy transfer (LETd) distribution. RESULTS The resulting energy spectra from Monte Carlo simulations indicate an optimal absorber thickness for providing low-energy protons with maximum efficiency of proton fluence at an user-requested energy range for experiments. For instance, providing energies lower than 5 MeV, an energy spectrum with a relative total efficiency of 38.6 % to the initial spectrum was obtained with the optimal setup. The measurements of the depth dose, compared to the Monte Carlo simulations, showed that the dosimetry of low-energy protons works and protons with high LETd down to the range of α -particles can be produced. CONCLUSIONS This work provides a method for generating all clinically and radiobiologically relevant energies - especially down to the few-MeV level - at one clinical facility with pencil beam scanning. Thereby, it enables radiobiological experiments under environmentally uniform conditions.
Collapse
Affiliation(s)
- Carina Behrends
- West German Proton Therapy Centre Essen (WPE), 45147 Essen, Germany.,Department of Physics, TU Dortmund University, 44227 Dortmund, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, 45147 Essen, Germany
| | - Christian Bäumer
- West German Proton Therapy Centre Essen (WPE), 45147 Essen, Germany.,Department of Physics, TU Dortmund University, 44227 Dortmund, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, 45147 Essen, Germany.,German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
| | - Nico Verbeek
- West German Proton Therapy Centre Essen (WPE), 45147 Essen, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, 45147 Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, 45147 Essen, Germany
| | - Jens Ehlert
- Institute for Laser and Plasma Physics, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany.,Department of Haematology, Oncology and Clinical Immunology, Heinrich-Heine-University Düsseldorf, Medical Faculty, 40225 Düsseldorf, Germany
| | - Rajendra Prasad
- Institute for Laser and Plasma Physics, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Jörg Wulff
- West German Proton Therapy Centre Essen (WPE), 45147 Essen, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, 45147 Essen, Germany
| | - Armin Lühr
- Department of Physics, TU Dortmund University, 44227 Dortmund, Germany
| | - Beate Timmermann
- West German Proton Therapy Centre Essen (WPE), 45147 Essen, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, 45147 Essen, Germany.,German Cancer Consortium (DKTK), 69120 Heidelberg, Germany.,Faculty of Medicine, University of Duisburg-Essen, 45147 Essen, Germany.,Department of Particle Therapy, University Hospital Essen, 45147 Essen, Germany
| |
Collapse
|
5
|
Santos T, Ventura T, Lopes MDC. A review on radiochromic film dosimetry for dose verification in high energy photon beams. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.109217] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
6
|
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
|