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Debrot E, Liu P, Gardner M, Heng SM, Chan CH, Corde S, Downes S, Jackson M, Keall P. Nano X Image Guidance in radiation therapy: feasibility study protocol for cone beam computed tomography imaging with gravity-induced motion. Pilot Feasibility Stud 2023; 9:95. [PMID: 37312127 DOI: 10.1186/s40814-023-01340-z] [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: 05/02/2022] [Accepted: 06/07/2023] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND This paper describes the protocol for the Nano X Image Guidance (Nano X IG) trial, a single-institution, clinical imaging study. The Nano X is a prototype fixed-beam radiotherapy system developed to investigate the feasibility of a low-cost, compact radiotherapy system to increase global access to radiation therapy. This study aims to assess the feasibility of volumetric image guidance with cone beam computed tomography (CBCT) acquired during horizontal patient rotation on the Nano X radiotherapy system. METHODS In the Nano X IG study, we will determine whether radiotherapy image guidance can be performed with the Nano X radiotherapy system where the patient is horizontally rotated while scan projections are acquired. We will acquire both conventional CBCT scans and Nano X CBCT scans for 30 patients aged 18 and above and receiving radiotherapy for head/neck or upper abdomen cancers. For each patient, a panel of experts will assess the image quality of Nano X CBCT scans against conventional CBCT scans. Each patient will receive two Nano X CBCT scans to determine the image quality reproducibility, the extent and reproducibility of patient motion and assess patient tolerance. DISCUSSION Fixed-beam radiotherapy systems have the potential to help ease the current shortfall and increase global access to radiotherapy treatment. Advances in image guidance could facilitate fixed-beam radiotherapy using horizontal patient rotation. The efficacy of this radiotherapy approach is dependent on our ability to image and adapt to motion due to rotation and for patients to tolerate rotation during treatment. TRIAL REGISTRATION ClinicalTrials.gov, NCT04488224. Registered on 27 July 2020.
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Affiliation(s)
- Emily Debrot
- Faculty of Medicine and Health, ACRF Image X Institute, The University of Sydney, Camperdown, NSW, Australia
| | - Paul Liu
- Faculty of Medicine and Health, ACRF Image X Institute, The University of Sydney, Camperdown, NSW, Australia
| | - Mark Gardner
- Faculty of Medicine and Health, ACRF Image X Institute, The University of Sydney, Camperdown, NSW, Australia.
| | - Soo Min Heng
- Nelune Comprehensive Cancer Centre, Prince of Wales Hospital, Randwick, NSW, Australia
| | - Chin Hwa Chan
- Nelune Comprehensive Cancer Centre, Prince of Wales Hospital, Randwick, NSW, Australia
| | - Stephanie Corde
- Nelune Comprehensive Cancer Centre, Prince of Wales Hospital, Randwick, NSW, Australia
| | - Simon Downes
- Nelune Comprehensive Cancer Centre, Prince of Wales Hospital, Randwick, NSW, Australia
| | - Michael Jackson
- Nelune Comprehensive Cancer Centre, Prince of Wales Hospital, Randwick, NSW, Australia
| | - Paul Keall
- Faculty of Medicine and Health, ACRF Image X Institute, The University of Sydney, Camperdown, NSW, Australia
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Chen X, Cao Y, Zhang K, Wang Z, Xie X, Wang Y, Men K, Dai J. Technical note: A method to synthesize magnetic resonance images in different patient rotation angles with deep learning for gantry-free radiotherapy. Med Phys 2023; 50:1746-1755. [PMID: 36135718 DOI: 10.1002/mp.15981] [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: 12/28/2021] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Recently, patient rotating devices for gantry-free radiotherapy, a new approach to implement external beam radiotherapy, have been introduced. When a patient is rotated in the horizontal position, gravity causes anatomic deformation. For treatment planning, one feasible method is to acquire simulation images at different horizontal rotation angles. PURPOSE This study aimed to investigate the feasibility of synthesizing magnetic resonance (MR) images at patient rotation angles of 180° (prone position) and 90° (lateral position) from those at a rotation angle of 0° (supine position) using deep learning. METHODS This study included 23 healthy male volunteers. They underwent MR imaging (MRI) in the supine position and then in the prone (23 volunteers) and lateral (16 volunteers) positions. T1-weighted fast spin echo was performed for all positions with the same parameters. Two two-dimensional deep learning networks, pix2pix generative adversarial network (pix2pix GAN) and CycleGAN, were developed for synthesizing MR images in the prone and lateral positions from those in the supine position, respectively. For the evaluation of the models, leave-one-out cross-validation was performed. The mean absolute error (MAE), Dice similarity coefficient (DSC), and Hausdorff distance (HD) were used to determine the agreement between the prediction and ground truth for the entire body and four specific organs. RESULTS For pix2pix GAN, the synthesized images were visually bad, and no quantitative evaluation was performed. The quantitative evaluation metrics of the body outlines calculated for the synthesized prone and lateral images using CycleGAN were as follows: MAE, 35.63 ± 3.98 and 40.45 ± 5.83, respectively; DSC, 0.97 ± 0.01 and 0.94 ± 0.01, respectively; and HD (in pixels), 16.74 ± 3.55 and 31.69 ± 12.03, respectively. The quantitative metrics of the bladder and prostate performed were also promising for both the prone and lateral images, with mean values >0.90 in DSC (p > 0.05). The mean DSC and HD values of the bilateral femur for the prone images were 0.96 and 3.63 (in pixels), respectively, and 0.78 and 12.65 (in pixels) for the lateral images, respectively (p < 0.05). CONCLUSIONS The CycleGAN could synthesize the MRI at lateral and prone positions using images at supine position, and it could benefit gantry-free radiation therapy.
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Affiliation(s)
- Xinyuan Chen
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- National Cancer Center/National Clinical Research Center for Cancer/Hebei Cancer Hospital, Chinese Academy of Medical Sciences, Langfang, China
| | - Ying Cao
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kaixuan Zhang
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zhen Wang
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xuejie Xie
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yunxiang Wang
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kuo Men
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianrong Dai
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Addo DA, Kaufmann EE, Tagoe SN, Kyere AK. Characterization of GafChromic EBT2 film dose measurements using a tissue-equivalent water phantom for a Theratron® Equinox Cobalt-60 teletherapy machine. PLoS One 2022; 17:e0271000. [PMID: 35984784 PMCID: PMC9390906 DOI: 10.1371/journal.pone.0271000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 06/21/2022] [Indexed: 11/19/2022] Open
Abstract
Purpose
In vivo dosimetry is a quality assurance tool that provides post-treatment measurement of the absorbed dose as delivered to the patient. This dosimetry compares the prescribed and measured dose delivered to the target volume. In this study, a tissue-equivalent water phantom provided the simulation of the human environment. The skin and entrance doses were measured using GafChromic EBT2 film for a Theratron® Equinox Cobalt-60 teletherapy machine.
Methods
We examined the behaviors of unencapsulated films and custom-made film encapsulation. Films were cut to 1 cm × 1 cm, calibrated, and used to assess skin dose depositions and entrance dose. We examined the response of the film for variations in field size, source to skin distance (SSD), gantry angle and wedge angle.
Results
The estimated uncertainty in EBT2 film for absorbed dose measurement in phantom was ±1.72%. Comparison of the measurements of the two film configurations for the various irradiation parameters were field size (p = 0.0193, α = 0.05, n = 11), gantry angle (p = 0.0018, α = 0.05, n = 24), SSD (p = 0.1802, α = 0.05, n = 11) and wedge angle (p = 0.6834, α = 0.05, n = 4). For a prescribed dose of 200 cGy and at reference conditions (open field 10 cm x 10 cm, SSD = 100 cm, and gantry angle = 0º), the measured skin dose using the encapsulation material was 70% while that measured with the unencapsulated film was 24%. At reference irradiation conditions, the measured skin dose using the unencapsulated film was higher for open field configurations (24%) than wedged field configurations (19%). Estimation of the entrance dose using the unencapsulated film was within 3% of the prescribed dose.
Conclusions
GafChromic EBT2 film measurements were significantly affected at larger field sizes and gantry angles. Furthermore, we determined a high accuracy in entrance dose estimations using the film.
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Affiliation(s)
- Daniel Akwei Addo
- Department of Computer Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- * E-mail:
| | - Elsie Effah Kaufmann
- Department of Biomedical Engineering, School of Engineering Sciences, University of Ghana, Legon, Accra, Ghana
| | - Samuel Nii Tagoe
- National Radiotherapy Oncology and Nuclear Medicine Centre, Korle-Bu, Accra, Ghana
- School of Biomedical and Allied health Sciences, University of Ghana, Accra, Ghana
| | - Augustine Kwame Kyere
- Medical Physics Department, Graduate School of Nuclear and Allied Sciences, University of Ghana, Atomic, Accra, Ghana
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Gardner M, Dillon O, Shieh CC, O'Brien R, Debrot E, Barber J, Ahern V, Bennett P, Heng SM, Corde S, Jackson M, Keall P. The adaptation and investigation of cone-beam CT reconstruction algorithms for horizontal rotation fixed-gantry scans of rabbits. Phys Med Biol 2021; 66. [PMID: 33878747 DOI: 10.1088/1361-6560/abf9dd] [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: 02/11/2021] [Accepted: 04/20/2021] [Indexed: 11/11/2022]
Abstract
Fixed-gantry radiation therapy has been proposed as a low-cost alternative to the conventional rotating-gantry radiation therapy, that may help meet the rising global treatment demand. Fixed-gantry systems require gravitational motion compensated reconstruction algorithms to produce cone-beam CT (CBCT) images of sufficient quality for image guidance. The aim of this work was to adapt and investigate five CBCT reconstruction algorithms for fixed-gantry CBCT images. The five algorithms investigated were Feldkamp-Davis-Kress (FDK), prior image constrained compressed sensing (PICCS), gravitational motion compensated FDK (GMCFDK), motion compensated PICCS (MCPICCS) (a novel CBCT reconstruction algorithm) and simultaneous motion estimation and iterative reconstruction (SMEIR). Fixed-gantry and rotating-gantry CBCT scans were acquired of 3 rabbits, with the rotating-gantry scans used as a reference. Projections were sorted into rotation bins, based on the angle of rotation of the rabbit during image acquisition. The algorithms were compared using the structural similarity index measure root mean square error, and reconstruction time. Evaluation of the reconstructed volumes showed that, when compared with the reference rotating-gantry volume, the conventional FDK algorithm did not accurately reconstruct fixed-gantry CBCT scans. Whilst the PICCS reconstruction algorithm reduced some motion artefacts, the motion estimation reconstruction methods (GMCFDK, MCPICCS and SMEIR) were able to greatly reduce the effect of motion artefacts on the reconstructed volumes. This finding was verified quantitatively, with GMCFDK, MCPICCS and SMEIR reconstructions having RMSE 17%-19% lower and SSIM 1% higher than a conventional FDK. However, all motion compensated fixed-gantry CBCT reconstructions had a 56%-61% higher RMSE and 1.5% lower SSIM than FDK reconstructions of conventional rotating-gantry CBCT scans. The results show that motion compensation is required to reduce motion artefacts for fixed-gantry CBCT reconstructions. This paper further demonstrates the feasibility of fixed-gantry CBCT scans, and the ability of CBCT reconstruction algorithms to compensate for motion due to horizontal rotation.
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Affiliation(s)
- Mark Gardner
- ACRF Image X Institute, The University of Sydney, Eveleigh, NSW 2015, Australia
| | - Owen Dillon
- ACRF Image X Institute, The University of Sydney, Eveleigh, NSW 2015, Australia
| | - Chun-Chien Shieh
- ACRF Image X Institute, The University of Sydney, Eveleigh, NSW 2015, Australia.,Sydney Neuroimaging Analysis Centre, Camperdown, NSW 2050, Australia
| | - Ricky O'Brien
- ACRF Image X Institute, The University of Sydney, Eveleigh, NSW 2015, Australia
| | - Emily Debrot
- ACRF Image X Institute, The University of Sydney, Eveleigh, NSW 2015, Australia
| | - Jeffrey Barber
- Western Sydney Local Health District, Blacktown, NSW 2148, Australia
| | - Verity Ahern
- Western Sydney Local Health District, Blacktown, NSW 2148, Australia
| | - Peter Bennett
- Faculty of Science, The University of Sydney, Camperdown, NSW 2006, Australia
| | - Soo-Min Heng
- Nelune Comprehensive Cancer Centre, Randwick, NSW 2031, Australia
| | - Stéphanie Corde
- Nelune Comprehensive Cancer Centre, Randwick, NSW 2031, Australia
| | - Michael Jackson
- Nelune Comprehensive Cancer Centre, Randwick, NSW 2031, Australia
| | - Paul Keall
- ACRF Image X Institute, The University of Sydney, Eveleigh, NSW 2015, Australia
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Liu PZY, Gardner M, Heng SM, Shieh CC, Nguyen DT, Debrot E, O'Brien R, Downes S, Jackson M, Keall PJ. Pre-treatment and real-time image guidance for a fixed-beam radiotherapy system. Phys Med Biol 2021; 66:064003. [PMID: 33661762 DOI: 10.1088/1361-6560/abdc12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE A radiotherapy system with a fixed treatment beam and a rotating patient positioning system could be smaller, more robust and more cost effective compared to conventional rotating gantry systems. However, patient rotation could cause anatomical deformation and compromise treatment delivery. In this work, we demonstrate an image-guided treatment workflow with a fixed beam prototype system that accounts for deformation during rotation to maintain dosimetric accuracy. METHODS The prototype system consists of an Elekta Synergy linac with the therapy beam orientated downward and a custom-built patient rotation system (PRS). A phantom that deforms with rotation was constructed and rotated within the PRS to quantify the performance of two image guidance techniques: motion compensated cone-beam CT (CBCT) for pre-treatment volumetric imaging and kilovoltage infraction monitoring (KIM) for real-time image guidance. The phantom was irradiated with a 3D conformal beam to evaluate the dosimetric accuracy of the workflow. RESULTS The motion compensated CBCT was used to verify pre-treatment position and the average calculated position was within -0.3 ± 1.1 mm of the phantom's ground truth position at 0°. KIM tracked the position of the target in real-time as the phantom was rotated and the average calculated position was within -0.2 ± 0.8 mm of the phantom's ground truth position. A 3D conformal treatment delivered on the prototype system with image guidance had a 3%/2 mm gamma pass rate of 96.3% compared to 98.6% delivered using a conventional rotating gantry linac. CONCLUSIONS In this work, we have shown that image guidance can be used with fixed-beam treatment systems to measure and account for changes in target position in order to maintain dosimetric coverage during horizontal rotation. This treatment modality could provide a viable treatment option when there insufficient space for a conventional linear accelerator or where the cost is prohibitive.
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Affiliation(s)
- Paul Z Y Liu
- ACRF Image X Institute, University of Sydney Central Clinical School, Sydney, NSW, Australia
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Zhao W, Patil I, Han B, Yang Y, Xing L, Schüler E. Beam data modeling of linear accelerators (linacs) through machine learning and its potential applications in fast and robust linac commissioning and quality assurance. Radiother Oncol 2020; 153:122-129. [PMID: 33039427 DOI: 10.1016/j.radonc.2020.09.057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND PURPOSE To propose a novel machine learning-based method for reliable and accurate modeling of linac beam data applicable to the processes of linac commissioning and QA. MATERIALS AND METHODS We hypothesize that the beam data is a function of inherent linac features and percentage depth doses (PDDs) and profiles of different field sizes are correlated with each other. The correlation is formulated as a multivariable regression problem using a machine learning framework. Varian TrueBeam beam data sets (n = 43) acquired from multiple institutions were used to evaluate the framework. The data sets included PDDs and profiles across different energies and field sizes. A multivariate regression model was trained for prediction of beam specific PDDs and profiles of different field sizes using a 10 × 10 cm2 field as input. RESULTS Predictions of PDDs were achieved with a mean absolute percent relative error (%RE) of 0.19-0.35% across the different beam energies investigated. The maximum mean absolute %RE was 0.93%. For profile prediction, the mean absolute %RE was 0.66-0.93% with a maximum absolute %RE of 3.76%. The largest uncertainties in the PDD and profile predictions were found at the build-up region and at the field penumbra, respectively. The prediction accuracy increased with the number of training sets up to around 20 training sets. CONCLUSIONS Through this novel machine learning-based method we have shown accurate and reproducible generation of beam data for linac commissioning for routine radiation therapy. This method has the potential to simplify the linac commissioning procedure, save time and manpower while increasing the accuracy of the commissioning process.
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Affiliation(s)
- Wei Zhao
- Stanford University, Department of Radiation Oncology, Stanford, CA 94305, USA.
| | - Ishan Patil
- Stanford University, Department of Radiation Oncology, Stanford, CA 94305, USA
| | - Bin Han
- Stanford University, Department of Radiation Oncology, Stanford, CA 94305, USA.
| | - Yong Yang
- Stanford University, Department of Radiation Oncology, Stanford, CA 94305, USA.
| | - Lei Xing
- Stanford University, Department of Radiation Oncology, Stanford, CA 94305, USA.
| | - Emil Schüler
- Stanford University, Department of Radiation Oncology, Stanford, CA 94305, USA; The University of Texas MD Anderson Cancer Center, Department of Radiation Physics, Houston, TX 77030, USA.
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Buckley JG, Rai R, Liney GP, Dowling JA, Holloway LC, Metcalfe PE, Keall PJ. Anatomical deformation due to horizontal rotation: towards gantry-free radiation therapy. ACTA ACUST UNITED AC 2019; 64:175014. [DOI: 10.1088/1361-6560/ab324c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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