1
|
Benzazon N, Carré A, de Kermenguy F, Niyoteka S, Maury P, Colnot J, M'hamdi M, Aichi ME, Veres C, Allodji R, de Vathaire F, Sarrut D, Journy N, Alapetite C, Grégoire V, Deutsch E, Diallo I, Robert C. Deep-Learning for Rapid Estimation of the Out-of-Field Dose in External Beam Photon Radiation Therapy - A Proof of Concept. Int J Radiat Oncol Biol Phys 2024:S0360-3016(24)00423-1. [PMID: 38554830 DOI: 10.1016/j.ijrobp.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 02/26/2024] [Accepted: 03/07/2024] [Indexed: 04/02/2024]
Abstract
PURPOSE The dose deposited outside of the treatment field during external photon beam radiation therapy treatment, also known as out-of-field dose, is the subject of extensive study as it may be associated with a higher risk of developing a second cancer and could have deleterious effects on the immune system that compromise the efficiency of combined radio-immunotherapy treatments. Out-of-field dose estimation tools developed today in research, including Monte Carlo simulations and analytical methods, are not suited to the requirements of clinical implementation because of their lack of versatility and their cumbersome application. We propose a proof of concept based on deep learning for out-of-field dose map estimation that addresses these limitations. METHODS AND MATERIALS For this purpose, a 3D U-Net, considering as inputs the in-field dose, as computed by the treatment planning system, and the patient's anatomy, was trained to predict out-of-field dose maps. The cohort used for learning and performance evaluation included 3151 pediatric patients from the FCCSS database, treated in 5 clinical centers, whose whole-body dose maps were previously estimated with an empirical analytical method. The test set, composed of 433 patients, was split into 5 subdata sets, each containing patients treated with devices unseen during the training phase. Root mean square deviation evaluated only on nonzero voxels located in the out-of-field areas was computed as performance metric. RESULTS Root mean square deviations of 0.28 and 0.41 cGy/Gy were obtained for the training and validation data sets, respectively. Values of 0.27, 0.26, 0.28, 0.30, and 0.45 cGy/Gy were achieved for the 6 MV linear accelerator, 16 MV linear accelerator, Alcyon cobalt irradiator, Mobiletron cobalt irradiator, and betatron device test sets, respectively. CONCLUSIONS This proof-of-concept approach using a convolutional neural network has demonstrated unprecedented generalizability for this task, although it remains limited, and brings us closer to an implementation compatible with clinical routine.
Collapse
Affiliation(s)
- Nathan Benzazon
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France.
| | - Alexandre Carré
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| | - François de Kermenguy
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| | - Stéphane Niyoteka
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| | - Pauline Maury
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| | - Julie Colnot
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France; THERYQ, PMB-Alcen, Peynier, France
| | - Meissane M'hamdi
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| | - Mohammed El Aichi
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| | - Cristina Veres
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| | - Rodrigue Allodji
- Unité Mixte de Recherche (UMR) 1018 Centre de Recherche en épidémiologie et Santé des Populations (CESP), Radiation Epidemiology Team, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France
| | - Florent de Vathaire
- Unité Mixte de Recherche (UMR) 1018 Centre de Recherche en épidémiologie et Santé des Populations (CESP), Radiation Epidemiology Team, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France
| | - David Sarrut
- Université de Lyon; CREATIS; CNRS UMR5220; Inserm U1294; INSA-Lyon; Léon Bérard cancer center, Lyon, France
| | - Neige Journy
- Unité Mixte de Recherche (UMR) 1018 Centre de Recherche en épidémiologie et Santé des Populations (CESP), Radiation Epidemiology Team, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France
| | | | - Vincent Grégoire
- Department of Radiation Oncology, centre Léon-Bérard, Lyon, France
| | - Eric Deutsch
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| | - Ibrahima Diallo
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| | - Charlotte Robert
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Inserm, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France
| |
Collapse
|
2
|
Benzazon N, Colnot J, de Kermenguy F, Achkar S, de Vathaire F, Deutsch E, Robert C, Diallo I. Analytical models for external photon beam radiotherapy out-of-field dose calculation: a scoping review. Front Oncol 2023; 13:1197079. [PMID: 37228501 PMCID: PMC10203488 DOI: 10.3389/fonc.2023.1197079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023] Open
Abstract
A growing body of scientific evidence indicates that exposure to low dose ionizing radiation (< 2 Gy) is associated with a higher risk of developing radio-induced cancer. Additionally, it has been shown to have significant impacts on both innate and adaptive immune responses. As a result, the evaluation of the low doses inevitably delivered outside the treatment fields (out-of-field dose) in photon radiotherapy is a topic that is regaining interest at a pivotal moment in radiotherapy. In this work, we proposed a scoping review in order to identify evidence of strengths and limitations of available analytical models for out-of-field dose calculation in external photon beam radiotherapy for the purpose of implementation in clinical routine. Papers published between 1988 and 2022 proposing a novel analytical model that estimated at least one component of the out-of-field dose for photon external radiotherapy were included. Models focusing on electrons, protons and Monte-Carlo methods were excluded. The methodological quality and potential limitations of each model were analyzed to assess their generalizability. Twenty-one published papers were selected for analysis, of which 14 proposed multi-compartment models, demonstrating that research efforts are directed towards an increasingly detailed description of the underlying physical phenomena. Our synthesis revealed great inhomogeneities in practices, in particular in the acquisition of experimental data and the standardization of measurements, in the choice of metrics used for the evaluation of model performance and even in the definition of regions considered out-of-the-field, which makes quantitative comparisons impossible. We therefore propose to clarify some key concepts. The analytical methods do not seem to be easily suitable for massive use in clinical routine, due to the inevitable cumbersome nature of their implementation. Currently, there is no consensus on a mathematical formalism that comprehensively describes the out-of-field dose in external photon radiotherapy, partly due to the complex interactions between a large number of influencing factors. Out-of-field dose calculation models based on neural networks could be promising tools to overcome these limitations and thus favor a transfer to the clinic, but the lack of sufficiently large and heterogeneous data sets is the main obstacle.
Collapse
Affiliation(s)
- Nathan Benzazon
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
- Department of Radiation Oncology, Gustave Roussy, Villejuif, France
| | - Julie Colnot
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
- Department of Radiation Oncology, Gustave Roussy, Villejuif, France
- THERYQ, PMB-Alcen, Peynier, France
| | - François de Kermenguy
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
- Department of Radiation Oncology, Gustave Roussy, Villejuif, France
| | - Samir Achkar
- Department of Radiation Oncology, Gustave Roussy, Villejuif, France
| | - Florent de Vathaire
- Unité Mixte de Recherche (UMR) 1018 Centre de Recherche en épidémiologie et Santé des Populations (CESP), Radiation Epidemiology Team, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
| | - Eric Deutsch
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
- Department of Radiation Oncology, Gustave Roussy, Villejuif, France
| | - Charlotte Robert
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
- Department of Radiation Oncology, Gustave Roussy, Villejuif, France
| | - Ibrahima Diallo
- Unité Mixte de Recherche (UMR) 1030 Radiothérapie Moléculaire et Innovation Thérapeutique, ImmunoRadAI, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
- Department of Radiation Oncology, Gustave Roussy, Villejuif, France
| |
Collapse
|
3
|
A publicly available dataset of out-of-field dose profiles of a 6 MV linear accelerator. Phys Eng Sci Med 2022; 45:613-621. [PMID: 35553016 DOI: 10.1007/s13246-022-01131-5] [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: 09/28/2021] [Accepted: 04/19/2022] [Indexed: 10/18/2022]
Abstract
An increase in radiotherapy-induced secondary malignancies has led to recent developments in analytical modelling of out-of-field dose. These models must be validated against measurements, but currently available datasets are outdated or limited in scope. This study aimed to address these shortcomings by producing a large dataset of out-of-field dose profiles measured with modern equipment. A novel method was developed with the intention of allowing physicists in all clinics to perform these measurements themselves using commonly available dosimetry equipment. A standard 3D scanning water tank was used to collect 36 extended profiles. Each profile was measured in two sections, with the inner section measured with the beam directly incident on the tank, and the outer section with the beam incident on a water-equivalent phantom abutted next to the tank. The two sections were then stitched using a novel feature-matching approach. The profiles were compared against linac commissioning data and manually inspected for discontinuities in the overlap region. The dataset is presented as a publicly accessible comma separated variable file containing off-axis ratios at a range of off-axis distances. This dataset may be applied to the development and validation of analytical models of out-of-field dose. Additionally, it may be used to inform dose estimates to radiosensitive implants and anatomy. Physicists are encouraged to perform these out-of-field measurements in their own clinics and share their results with the community.
Collapse
|
4
|
Sun R, Achkar S, Ammari S, Bockel S, Gallois E, Bayle A, Battistella E, Salviat F, Merad M, Laville A, Ka K, Griscelli F, Albiges L, Barlesi F, Bossi A, Rivera S, Chargari C, Deutsch E. Systematic Screening of COVID-19 Disease Based on Chest CT and RT-PCR for Cancer Patients Undergoing Radiation Therapy in a Coronavirus French Hotspot. Int J Radiat Oncol Biol Phys 2021; 110:947-956. [PMID: 33609591 PMCID: PMC7887448 DOI: 10.1016/j.ijrobp.2021.02.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 02/10/2021] [Accepted: 02/10/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE Patients with cancer are presumed to be more vulnerable to COVID-19. We evaluated a screening strategy combining chest computed tomography (CT) and reverse-transcription polymerase chain reaction (RT-PCR) for patients treated with radiation therapy at our cancer center located in a COVID-19 French hotspot during the first wave of the pandemic. METHODS AND MATERIALS Chest CT images were proposed during radiation therapy CT simulation. Images were reviewed by an expert radiologist according to the COVID-19 Reporting and Data System classification. Nasal swabs with RT-PCR assay were initially proposed in cases of suspicious imaging or clinical context and were eventually integrated into the systematic screening. A dedicated radiation therapy workflow was proposed for COVID-19 patients to limit the risk of contamination. RESULTS From March 18, 2020 to May 1, 2020, 480 patients were screened by chest CT, and 313 patients had both chest CT and RT-PCR (65%). The cumulative incidence of COVID-19 was 5.4% (95% confidence interval [CI], 3.6-7.8; 26 of 480 patients). Diagnosis of COVID-19 was made before radiation therapy for 22 patients (84.6%) and during RT for 4 patients (15.3%). Chest CT directly aided the diagnosis of 7 cases in which the initial RT-PCR was negative or not feasible, out of a total of 480 patients (1.5%) and 517 chest CT acquisitions. Four patients with COVID-19 at the time of the chest CT screening had a false negative CT. Sensitivity and specificity of chest CT screening in patients with both RT-PCR and chest CT testing were estimated at 0.82 (95% CI, 0.60-0.95) and 0.98 (95% CI, 0.96-0.99), respectively. Adaptation of the radiation therapy treatment was made for all patients, with 7 postponed treatments (median: 5 days; interquartile range, 1.5-14.8). CONCLUSIONS The benefit of systematic use of chest CT screening during CT simulation for patients undergoing radiation therapy during the COVID-19 pandemic seemed limited.
Collapse
Affiliation(s)
- Roger Sun
- Department of Radiation Oncology, Gustave Roussy, Paris-Saclay University, Villejuif, France; Radiothérapie Moléculaire et Innovation Thérapeutique, Paris-Saclay University, Gustave Roussy, Villejuif, France
| | - Samir Achkar
- Department of Radiation Oncology, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Samy Ammari
- Department of Radiology, Gustave Roussy, Paris-Saclay University, Villejuif, France; BioMaps (UMR1281), Université Paris-Saclay, CNRS, INSERM, CEA, Orsay and Gustave Roussy, Villejuif, France
| | - Sophie Bockel
- Department of Radiation Oncology, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Emmanuelle Gallois
- Department of Biopathology, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Arnaud Bayle
- Department of Cancer Medicine, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Enzo Battistella
- Radiothérapie Moléculaire et Innovation Thérapeutique, Paris-Saclay University, Gustave Roussy, Villejuif, France
| | - Flore Salviat
- Department of Biostatistics, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Mansouria Merad
- Department of Cancer Medicine, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Adrien Laville
- Department of Radiation Oncology, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Kanta Ka
- Department of Radiation Oncology, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Franck Griscelli
- Department of Biopathology, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Laurence Albiges
- Department of Cancer Medicine, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Fabrice Barlesi
- Department of Cancer Medicine, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Alberto Bossi
- Department of Radiation Oncology, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Sofia Rivera
- Department of Radiation Oncology, Gustave Roussy, Paris-Saclay University, Villejuif, France
| | - Cyrus Chargari
- Department of Radiation Oncology, Gustave Roussy, Paris-Saclay University, Villejuif, France; Radiothérapie Moléculaire et Innovation Thérapeutique, Paris-Saclay University, Gustave Roussy, Villejuif, France
| | - Eric Deutsch
- Department of Radiation Oncology, Gustave Roussy, Paris-Saclay University, Villejuif, France; Radiothérapie Moléculaire et Innovation Thérapeutique, Paris-Saclay University, Gustave Roussy, Villejuif, France.
| |
Collapse
|
5
|
Kang DJ, Shin YJ, Jeong S, Jung JY, Lee H, Lee B. Development of clinical application program for radiotherapy induced cancer risk calculation using Monte Carlo engine in volumetric-modulated arc therapy. Radiat Oncol 2021; 16:108. [PMID: 34118968 PMCID: PMC8199704 DOI: 10.1186/s13014-020-01722-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 12/06/2020] [Indexed: 11/10/2022] Open
Abstract
Background The purpose of this study is to develop a clinical application program that automatically calculates the effect for secondary cancer risk (SCR) of individual patient. The program was designed based on accurate dose calculations using patient computed tomography (CT) data and Monte Carlo engine. Automated patient-specific evaluation program was configured to calculate SCR. Methods The application program is designed to re-calculate the beam sequence of treatment plan using the Monte Carlo engine and patient CT data, so it is possible to accurately calculate and evaluate scatter and leakage radiation, difficult to calculate in TPS. The Monte Carlo dose calculation system was performed through stoichiometric calibration using patient CT data. The automatic SCR evaluation program in application program created with a MATLAB was set to analyze the results to calculate SCR. The SCR for organ of patient was calculated based on Biological Effects of Ionizing Radiation (BEIR) VII models. The program is designed to sequentially calculate organ equivalent dose (OED), excess absolute risk (EAR), excess relative risk (ERR), and the lifetime attributable risk (LAR) in consideration of 3D dose distribution analysis. In order to confirm the usefulness of the developed clinical application program, the result values from clinical application program were compared with the manual calculation method used in the previous study. Results The OED values calculated in program were calculated to be at most approximately 13.3% higher than results in TPS. The SCR result calculated by the developed clinical application program showed a maximum difference of 1.24% compared to the result of the conventional manual calculation method. And it was confirmed that EAR, ERR and LAR values can be easily calculated by changing the biological parameters. Conclusions We have developed a patient-specific SCR evaluation program that can be used conveniently in the clinic. The program consists of a Monte Carlo dose calculation system for accurate calculation of scatter and leakage radiation and a patient-specific automatic SCR evaluation program using 3D dose distribution. The clinical application program that improved the disadvantages of the existing process can be used as an index for evaluating a patient treatment plan.
Collapse
Affiliation(s)
- Dong-Jin Kang
- Department of Radiation Oncology, Inje University Sanggye Paik Hospital, 1342, Dongil-ro, Nowon-gu, Seoul, Korea
| | - Young-Joo Shin
- Department of Radiation Oncology, Inje University Sanggye Paik Hospital, 1342, Dongil-ro, Nowon-gu, Seoul, Korea.
| | - Seonghoon Jeong
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Jae-Yong Jung
- Department of Radiation Oncology, Inje University Sanggye Paik Hospital, 1342, Dongil-ro, Nowon-gu, Seoul, Korea
| | | | - Boram Lee
- Department of Radiation Oncology, Samsung Medical Center, School of Medicine, Sungkyunkwan University, 81, Irwon-Ro, Gangnam-Gu, Seoul, 06351, Korea.
| |
Collapse
|
6
|
Ade N, du Plessis FCP. Out-of-field scattering from the Integral Quality Monitor® in megavolt photon beams. Appl Radiat Isot 2020; 168:109449. [PMID: 33317891 DOI: 10.1016/j.apradiso.2020.109449] [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: 08/20/2020] [Accepted: 09/24/2020] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate out-of-field scattered doses from the Integral Quality Monitor (IQM) transmission detector in megavoltage photon beams. MATERIALS AND METHODS We measured out-of-field point doses for 20 × 20 cm2 6-15 MV photon beams using 10 × 2 cm2 Gafchromic EBT3 film strips placed across the surfaces of 5-cm thick water-equivalent RW3 slabs. The films were placed at 10 cm intervals from the central axis (CAX) of each beam, up to 1.0 m away on opposite sides of the CAX. The measurements were conducted at 80 cm and 100 cm source-to-surface distances (SSD) without the IQM, and were repeated with the IQM in the paths of the beams. Measurements were also performed at 90 cm SSD for 20 × 20 and 30 × 30 cm2 15 MV fields. Surface dose profiles were then constructed from the measurements for each beam setup with and without the IQM to examine the differences in scattered dose off-axis. The dose profile for each beam setup was normalised to dose maximum measured on the CAX. RESULTS Overall, surface dose profiles acquired with the IQM in the paths of the beams were higher than the corresponding profiles without the IQM. The out-of-field dose increased with increase in photon energy, field size, and shorter SSDs, and decreased with off-axis distance. At 80 cm SSD for the 20 × 20 cm2 field, the IQM-induced surface dose ranged from -0.6% ÷ 1.9%, -0.3% ÷ 3.0%, and 0.3% ÷ 6.8% for 6, 10, and 15 MV beams, respectively. CONCLUSION The higher surface dose profiles measured with the IQM attached to the linac compared to the profiles without the IQM indicates that the device is acting as an additional source of scattered radiation.
Collapse
Affiliation(s)
- Nicholas Ade
- Medical Physics Department, University of the Free State, Bloemfontein, 9300, South Africa.
| | - F C P du Plessis
- Medical Physics Department, University of the Free State, Bloemfontein, 9300, South Africa
| |
Collapse
|
7
|
Sun R, Ammari S, Bockel S, Achkar S, Merad M, Dercle L, Rivera S, Chargari C, Deutsch E. Optimization of Patient Management During the COVID-19 Pandemic: Chest CT Scan and PCR as Gatekeepers of the Radiation Therapy Workflow. Front Oncol 2020; 10:556334. [PMID: 33312944 PMCID: PMC7708327 DOI: 10.3389/fonc.2020.556334] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022] Open
Affiliation(s)
- Roger Sun
- Gustave Roussy, Département de Radiothérapie, INSERM 1030, Université Paris-Saclay, Villejuif, France
| | - Samy Ammari
- Gustave Roussy, Département d'Imagerie Médicale, Université Paris-Saclay, Villejuif, France
| | - Sophie Bockel
- Gustave Roussy, Département de Radiothérapie, INSERM 1030, Université Paris-Saclay, Villejuif, France
| | - Samir Achkar
- Gustave Roussy, Département de Radiothérapie, INSERM 1030, Université Paris-Saclay, Villejuif, France
| | - Mansouria Merad
- Gustave Roussy, Département d'Oncologie Médicale, Université Paris-Saclay, Villejuif, France
| | - Laurent Dercle
- Department of Radiology, Columbia University Irving Medical Center, New York, NY, United States
| | - Sofia Rivera
- Gustave Roussy, Département de Radiothérapie, INSERM 1030, Université Paris-Saclay, Villejuif, France
| | - Cyrus Chargari
- Gustave Roussy, Département de Radiothérapie, INSERM 1030, Université Paris-Saclay, Villejuif, France
| | - Eric Deutsch
- Gustave Roussy, Département de Radiothérapie, INSERM 1030, Université Paris-Saclay, Villejuif, France
| |
Collapse
|
8
|
Method to quickly and accurately calculate absorbed dose from therapeutic and stray photon exposures throughout the entire body in individual patients. Med Phys 2020; 47:2254-2266. [DOI: 10.1002/mp.14018] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/11/2019] [Accepted: 12/24/2019] [Indexed: 01/26/2023] Open
|
9
|
Wilson LJ, Newhauser WD, Schneider CW. An objective method to evaluate radiation dose distributions varying by three orders of magnitude. Med Phys 2019; 46:1888-1895. [PMID: 30714163 DOI: 10.1002/mp.13420] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/26/2018] [Accepted: 01/24/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Modern radiotherapy practices typically report the absorbed dose (D) within the 5% relative isodose volume (i.e., the therapeutic dose region) to an accuracy of 3%-5%. Gamma-index analysis, the most commonly used method to evaluate dosimetric accuracy, has low sensitivity to discrepancies that occur outside of this region. The objective of this study was to develop an evaluation method with high sensitivity across dose distributions spanning three orders of magnitude. METHODS We generalized the gamma index to include an additional criterion, the absolute absorbed dose difference, specifically for the low-dose region (i.e., D ≤ 5%). We also proposed a method to objectively select the appropriate magnitudes for relative-dose-difference, absolute-dose-difference, and distance-to-agreement criteria. We demonstrated the generalized gamma-index method by first finding the appropriate generalized gamma-index agreement criteria at an interval of specified passing rates. Next, we used the generalized gamma index to evaluate one-, two-, and three-dimensional absorbed dose distributions in a water-box phantom and voxelized patient geometry. RESULTS Generalized gamma-index passing rates for one-, two-, and three-dimensional dose distributions were 55.4%, 44.5%, and 8.9%, respectively. Traditional gamma-index passing rates were 100%, 97.8%, and 96.4%, respectively. These results reveal that the generalized method has adequate sensitivity in all regions (i.e., therapeutic and low dose). Additionally, the algorithmic determination of triplets of agreement criteria revealed that they are strong functions of the specified passing rate. CONCLUSIONS The major finding of this work is that the proposed method provides an objective evaluation of the agreement of dose distributions spanning three orders of magnitude. In particular, this generalized method correctly characterized dosimetric agreement in the low-dose region, which was not possible by traditional methods. The proposed algorithmic selection of agreement criteria decreased subjectivity and requirements of user judgment and skill. This method could find utility in a variety of applications including dose-algorithm development and translation.
Collapse
Affiliation(s)
- Lydia J Wilson
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803-4001, USA
| | - Wayne D Newhauser
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803-4001, USA.,Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, LA, 70809, USA
| | - Christopher W Schneider
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803-4001, USA
| |
Collapse
|
10
|
The PanCareSurFup consortium: research and guidelines to improve lives for survivors of childhood cancer. Eur J Cancer 2018; 103:238-248. [DOI: 10.1016/j.ejca.2018.08.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 08/10/2018] [Accepted: 08/26/2018] [Indexed: 01/20/2023]
|
11
|
Gallagher KJ, Tannous J, Nabha R, Feghali JA, Ayoub Z, Jalbout W, Youssef B, Taddei PJ. Supplemental computational phantoms to estimate out-of-field absorbed dose in photon radiotherapy. Phys Med Biol 2018; 63:025021. [PMID: 29099727 DOI: 10.1088/1361-6560/aa9838] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The purpose of this study was to develop a straightforward method of supplementing patient anatomy and estimating out-of-field absorbed dose for a cohort of pediatric radiotherapy patients with limited recorded anatomy. A cohort of nine children, aged 2-14 years, who received 3D conformal radiotherapy for low-grade localized brain tumors (LBTs), were randomly selected for this study. The extent of these patients' computed tomography simulation image sets were cranial only. To approximate their missing anatomy, we supplemented the LBT patients' image sets with computed tomography images of patients in a previous study with larger extents of matched sex, height, and mass and for whom contours of organs at risk for radiogenic cancer had already been delineated. Rigid fusion was performed between the LBT patients' data and that of the supplemental computational phantoms using commercial software and in-house codes. In-field dose was calculated with a clinically commissioned treatment planning system, and out-of-field dose was estimated with a previously developed analytical model that was re-fit with parameters based on new measurements for intracranial radiotherapy. Mean doses greater than 1 Gy were found in the red bone marrow, remainder, thyroid, and skin of the patients in this study. Mean organ doses between 150 mGy and 1 Gy were observed in the breast tissue of the girls and lungs of all patients. Distant organs, i.e. prostate, bladder, uterus, and colon, received mean organ doses less than 150 mGy. The mean organ doses of the younger, smaller LBT patients (0-4 years old) were a factor of 2.4 greater than those of the older, larger patients (8-12 years old). Our findings demonstrated the feasibility of a straightforward method of applying supplemental computational phantoms and dose-calculation models to estimate absorbed dose for a set of children of various ages who received radiotherapy and for whom anatomies were largely missing in their original computed tomography simulations.
Collapse
Affiliation(s)
- Kyle J Gallagher
- Oregon State University, Corvallis, OR, United States of America. Oregon Health and Science University, Portland, OR, United States of America
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Dose estimation outside radiation field using Pinpoint and Semiflex ionization chamber detectors. Radiat Phys Chem Oxf Engl 1993 2017. [DOI: 10.1016/j.radphyschem.2017.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
13
|
Low dose out-of-field radiotherapy, part 1: Measurement of scattered doses. Cancer Radiother 2017; 21:345-351. [DOI: 10.1016/j.canrad.2016.09.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 08/31/2016] [Accepted: 09/21/2016] [Indexed: 12/25/2022]
|
14
|
Schneider CW, Newhauser WD, Wilson LJ, Schneider U, Kaderka R, Miljanić S, Knežević Ž, Stolarcyzk L, Durante M, Harrison RM. A descriptive and broadly applicable model of therapeutic and stray absorbed dose from 6 to 25 MV photon beams. Med Phys 2017; 44:3805-3814. [PMID: 28429827 DOI: 10.1002/mp.12286] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 02/09/2017] [Accepted: 03/23/2017] [Indexed: 01/01/2023] Open
Abstract
PURPOSE To develop a simple model of therapeutic and stray absorbed dose for a variety of treatment machines and techniques without relying on proprietary machine-specific parameters. METHODS Dosimetry measurements conducted in this study and from the literature were used to develop an analytical model of absorbed dose from a variety of treatment machines and techniques in the 6 to 25 MV interval. A modified one-dimensional gamma-index analysis was performed to evaluate dosimetric accuracy of the model on an independent dataset consisting of measured dose profiles from seven treatment units spanning four manufacturers. RESULTS The average difference between the calculated and measured absorbed dose values was 9.9% for those datasets on which the model was trained. Additionally, these results indicate that the model can provide accurate calculations of both therapeutic and stray radiation dose from a wide variety of radiotherapy units and techniques. CONCLUSIONS We have developed a simple analytical model of absorbed dose from external beam radiotherapy treatments in the 6 to 25 MV beam energy range. The model has been tested on measured data from multiple treatment machines and techniques, and is broadly applicable to contemporary external beam radiation therapy.
Collapse
Affiliation(s)
- Christopher W Schneider
- Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, Baton Rouge, LA, 70803-4001, USA
| | - Wayne D Newhauser
- Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, Baton Rouge, LA, 70803-4001, USA.,Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, LA, 70809, USA
| | - Lydia J Wilson
- Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, Baton Rouge, LA, 70803-4001, USA
| | - Uwe Schneider
- Faculty of Science, University of Zürich, Winterthurerstrasse 260, 8057, Zürich, Switzerland.,Institute for Radiotherapy, Hirslanden Medical Center, Rain 34, 5000, Aarau, Switzerland
| | - Robert Kaderka
- GSI Helmholtzzentrum für Schwerionenforschung, Department of Biophysics, Darmstadt, 64291, Germany
| | - Saveta Miljanić
- Ruder Bošković Institute, Radiation Chemistry and Dosimetry Laboratory, Bijenićka 54, HR-10000, Zagreb, Croatia
| | - Željka Knežević
- Ruder Bošković Institute, Radiation Chemistry and Dosimetry Laboratory, Bijenićka 54, HR-10000, Zagreb, Croatia
| | - Liliana Stolarcyzk
- Bronowice Cyclotron Centre, Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342, Krakow, Poland
| | - Marco Durante
- Trento Institute for Fundamental Physics and Applications (TIFPA), National Institute of Nuclear Physics (INFN), University of Trento, Via Sommarive 14, 38123 Povo, Trento, Italy
| | - Roger M Harrison
- Faculty of Medical Sciences, University of Newcastle, Newcastle-upon-Tyne, NE2 4HH, UK
| |
Collapse
|
15
|
Vũ Bezin J, Allodji RS, Mège JP, Beldjoudi G, Saunier F, Chavaudra J, Deutsch E, de Vathaire F, Bernier V, Carrie C, Lefkopoulos D, Diallo I. A review of uncertainties in radiotherapy dose reconstruction and their impacts on dose-response relationships. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2017; 37:R1-R18. [PMID: 28118156 DOI: 10.1088/1361-6498/aa575d] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Proper understanding of the risk of radiation-induced late effects for patients receiving external photon beam radiotherapy requires the determination of reliable dose-response relationships. Although significant efforts have been devoted to improving dose estimates for the study of late effects, the most often questioned explanatory variable is still the dose. In this work, based on a literature review, we provide an in-depth description of the radiotherapy dose reconstruction process for the study of late effects. In particular, we focus on the identification of the main sources of dose uncertainty involved in this process and summarise their impacts on the dose-response relationship for radiotherapy late effects. We provide a number of recommendations for making progress in estimating the uncertainties in current studies of radiotherapy late effects and reducing these uncertainties in future studies.
Collapse
Affiliation(s)
- Jérémi Vũ Bezin
- Inserm, Radiation Epidemiology Team, CESP-U1018, F-94807, Villejuif, France. Gustave Roussy, Villejuif, F-94805, France. Paris-Sud University, Orsay, F-91400, France
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Hauri P, Hälg RA, Besserer J, Schneider U. A general model for stray dose calculation of static and intensity-modulated photon radiation. Med Phys 2016; 43:1955. [DOI: 10.1118/1.4944421] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
17
|
Sánchez-Nieto B, El-far R, Irazola L, Romero-Expósito M, Lagares JI, Mateo JC, Terrón JA, Doblado FS. Analytical model for photon peripheral dose estimation in radiotherapy treatments. Biomed Phys Eng Express 2015. [DOI: 10.1088/2057-1976/1/4/045205] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
18
|
Jagetic LJ, Newhauser WD. A simple and fast physics-based analytical method to calculate therapeutic and stray doses from external beam, megavoltage x-ray therapy. Phys Med Biol 2015; 60:4753-75. [PMID: 26040833 DOI: 10.1088/0031-9155/60/12/4753] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
State-of-the-art radiotherapy treatment planning systems provide reliable estimates of the therapeutic radiation but are known to underestimate or neglect the stray radiation exposures. Most commonly, stray radiation exposures are reconstructed using empirical formulas or lookup tables. The purpose of this study was to develop the basic physics of a model capable of calculating the total absorbed dose both inside and outside of the therapeutic radiation beam for external beam photon therapy. The model was developed using measurements of total absorbed dose in a water-box phantom from a 6 MV medical linear accelerator to calculate dose profiles in both the in-plane and cross-plane direction for a variety of square field sizes and depths in water. The water-box phantom facilitated development of the basic physical aspects of the model. RMS discrepancies between measured and calculated total absorbed dose values in water were less than 9.3% for all fields studied. Computation times for 10 million dose points within a homogeneous phantom were approximately 4 min. These results suggest that the basic physics of the model are sufficiently simple, fast, and accurate to serve as a foundation for a variety of clinical and research applications, some of which may require that the model be extended or simplified based on the needs of the user. A potentially important advantage of a physics-based approach is that the model is more readily adaptable to a wide variety of treatment units and treatment techniques than with empirical models.
Collapse
Affiliation(s)
- Lydia J Jagetic
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001, USA
| | | |
Collapse
|
19
|
Winther JF, Kenborg L, Byrne J, Hjorth L, Kaatsch P, Kremer LCM, Kuehni CE, Auquier P, Michel G, de Vathaire F, Haupt R, Skinner R, Madanat-Harjuoja LM, Tryggvadottir L, Wesenberg F, Reulen RC, Grabow D, Ronckers CM, van Dulmen-den Broeder E, van den Heuvel-Eibrink MM, Schindler M, Berbis J, Holmqvist AS, Gudmundsdottir T, de Fine Licht S, Bonnesen TG, Asdahl PH, Bautz A, Kristoffersen AK, Himmerslev L, Hasle H, Olsen JH, Hawkins MM. Childhood cancer survivor cohorts in Europe. Acta Oncol 2015; 54:655-68. [PMID: 25813473 DOI: 10.3109/0284186x.2015.1008648] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
With the advent of multimodality therapy, the overall five-year survival rate from childhood cancer has improved considerably now exceeding 80% in developed European countries. This growing cohort of survivors, with many years of life ahead of them, has raised the necessity for knowledge concerning the risks of adverse long-term sequelae of the life-saving treatments in order to provide optimal screening and care and to identify and provide adequate interventions. Childhood cancer survivor cohorts in Europe. Considerable advantages exist to study late effects in individuals treated for childhood cancer in a European context, including the complementary advantages of large population-based cancer registries and the unrivalled opportunities to study lifetime risks, together with rich and detailed hospital-based cohorts which fill many of the gaps left by the large-scale population-based studies, such as sparse treatment information. Several large national cohorts have been established within Europe to study late effects in individuals treated for childhood cancer including the Nordic Adult Life after Childhood Cancer in Scandinavia study (ALiCCS), the British Childhood Cancer Survivor Study (BCCSS), the Dutch Childhood Oncology Group (DCOG) LATER study, and the Swiss Childhood Cancer Survivor Study (SCCSS). Furthermore, there are other large cohorts, which may eventually become national in scope including the French Childhood Cancer Survivor Study (FCCSS), the French Childhood Cancer Survivor Study for Leukaemia (LEA), and the Italian Study on off-therapy Childhood Cancer Survivors (OTR). In recent years significant steps have been taken to extend these national studies into a larger pan-European context through the establishment of two large consortia - PanCareSurFup and PanCareLIFE. The purpose of this paper is to present an overview of the current large, national and pan-European studies of late effects after childhood cancer. This overview will highlight the strong cooperation across Europe, in particular the EU-funded collaborative research projects PanCareSurFup and PanCareLIFE. Overall goal. The overall goal of these large cohort studies is to provide every European childhood cancer survivor with better care and better long-term health so that they reach their full potential, and to the degree possible, enjoy the same quality of life and opportunities as their peers.
Collapse
|
20
|
Fernandez-Palomo C, Bräuer-Krisch E, Laissue J, Vukmirovic D, Blattmann H, Seymour C, Schültke E, Mothersill C. Use of synchrotron medical microbeam irradiation to investigate radiation-induced bystander and abscopal effects in vivo. Phys Med 2015; 31:584-95. [PMID: 25817634 DOI: 10.1016/j.ejmp.2015.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 01/01/2023] Open
Abstract
The question of whether bystander and abscopal effects are the same is unclear. Our experimental system enables us to address this question by allowing irradiated organisms to partner with unexposed individuals. Organs from both animals and appropriate sham and scatter dose controls are tested for expression of several endpoints such as calcium flux, role of 5HT, reporter assay cell death and proteomic profile. The results show that membrane related functions of calcium and 5HT are critical for true bystander effect expression. Our original inter-animal experiments used fish species whole body irradiated with low doses of X-rays, which prevented us from addressing the abscopal effect question. Data which are much more relevant in radiotherapy are now available for rats which received high dose local irradiation to the implanted right brain glioma. The data were generated using quasi-parallel microbeams at the biomedical beamline at the European Synchrotron Radiation Facility in Grenoble France. This means we can directly compare abscopal and "true" bystander effects in a rodent tumour model. Analysis of right brain hemisphere, left brain and urinary bladder in the directly irradiated animals and their unirradiated partners strongly suggests that bystander effects (in partner animals) are not the same as abscopal effects (in the irradiated animal). Furthermore, the presence of a tumour in the right brain alters the magnitude of both abscopal and bystander effects in the tissues from the directly irradiated animal and in the unirradiated partners which did not contain tumours, meaning the type of signal was different.
Collapse
Affiliation(s)
- Cristian Fernandez-Palomo
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
| | - Elke Bräuer-Krisch
- European Synchrotron Radiation Facility, BP 220 6, rue Jules Horowitz, 38043 Grenoble, France
| | - Jean Laissue
- University of Bern, Hochschulstrasse 4, CH-3012 Bern, Switzerland
| | - Dusan Vukmirovic
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | | | - Colin Seymour
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Elisabeth Schültke
- Department of Radiotherapy, Rostock University Medical Center, Südring 75, 18059 Rostock, Germany
| | - Carmel Mothersill
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| |
Collapse
|
21
|
Vũ Bezin J, Veres A, Lefkopoulos D, Chavaudra J, Deutsch E, de Vathaire F, Diallo I. Field size dependent mapping of medical linear accelerator radiation leakage. Phys Med Biol 2015; 60:2103-6. [DOI: 10.1088/0031-9155/60/5/2103] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
22
|
Aerts AM, Impens NREN, Baatout S, Benotmane MA, Camps J, Dabin JM, Derradji H, Grosche B, Horemans N, Jourdain JR, Moreels M, Perko T, Quintens R, Repussard J, Rühm W, Schneider T, Struelens L, Hardeman F. Joint research towards a better radiation protection-highlights of the Fifth MELODI Workshop. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2014; 34:931-56. [PMID: 25431966 DOI: 10.1088/0952-4746/34/4/931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
MELODI is the European platform dedicated to low-dose radiation risk research. From 7 October through 10 October 2013 the Fifth MELODI Workshop took place in Brussels, Belgium. The workshop offered the opportunity to 221 unique participants originating from 22 countries worldwide to update their knowledge and discuss radiation research issues through 118 oral and 44 poster presentations. In addition, the MELODI 2013 workshop was reaching out to the broader radiation protection community, rather than only the low-dose community, with contributions from the fields of radioecology, emergency and recovery preparedness, and dosimetry. In this review, we summarise the major scientific conclusions of the workshop, which are important to keep the MELODI strategic research agenda up-to-date and which will serve to establish a joint radiation protection research roadmap for the future.
Collapse
Affiliation(s)
- A M Aerts
- Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (SCK•CEN), Mol, Belgium
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Lonski P, Taylor ML, Franich RD, Kron T. A collimated detection system for assessing leakage dose from medical linear accelerators at the patient plane. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2013; 37:15-23. [PMID: 24318958 DOI: 10.1007/s13246-013-0235-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 12/02/2013] [Indexed: 12/29/2022]
Abstract
Leakage radiation from linear accelerators can make a significant contribution to healthy tissue dose in patients undergoing radiotherapy. In this work thermoluminescent dosimeters (LiF:Mg,Cu,P TLD chips) were used in a focused lead cone loaded with TLD chips for the purpose of evaluating leakage dose at the patient plane. By placing the TLDs at one end of a stereotactic cone, a focused measurement device is created; this was tested both in and out of the primary beam of a Varian 21-iX linac using 6 MV photons. Acrylic build up material of 1.2 cm thickness was used inside the cone and measurements made with either one or three TLD chips at a given distance from the target. Comparing the readings of three dosimeters in one plane inside the cone offered information regarding the orientation of the cone relative to a radiation source. Measurements in the patient plane with the linac gantry at various angles demonstrated that leakage dose was approximately 0.01% of the primary beam out of field when the cone was pointed directly towards the target and 0.0025% elsewhere (due to scatter within the gantry). No specific 'hot spots' (e.g., insufficient shielding or gaps at abutments) were observed. Focused cone measurements facilitate leakage dose measurements from the linac head directly at the patient plane and allow one to infer the fraction of leakage due to 'direct' photons (along the ray-path from the bremsstrahlung target) and that due to scattered photons.
Collapse
Affiliation(s)
- P Lonski
- Physical Sciences Department, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, VIC, 3002, Australia,
| | | | | | | |
Collapse
|