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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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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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Liu PZY, O'Brien R, Heng SM, Newall M, Downes S, Shieh CC, Corde S, Jackson M, Keall P. Development and commissioning of a full-size prototype fixed-beam radiotherapy system with horizontal patient rotation. Med Phys 2019; 46:1331-1340. [DOI: 10.1002/mp.13356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/27/2018] [Accepted: 12/17/2018] [Indexed: 12/25/2022] Open
Affiliation(s)
- Paul Zhi Yuan Liu
- ACRF Image X Institute; University of Sydney Central Clinical School; Sydney NSW Australia
| | - Ricky O'Brien
- ACRF Image X Institute; University of Sydney Central Clinical School; Sydney NSW Australia
| | - Soo-Min Heng
- Nelune Comprehensive Cancer Centre; Prince of Wales Hospital; Randwick NSW Australia
| | - Matthew Newall
- Nelune Comprehensive Cancer Centre; Prince of Wales Hospital; Randwick NSW Australia
| | - Simon Downes
- Nelune Comprehensive Cancer Centre; Prince of Wales Hospital; Randwick NSW Australia
| | - Chun-Chen Shieh
- ACRF Image X Institute; University of Sydney Central Clinical School; Sydney NSW Australia
| | - Stephanie Corde
- 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
- ACRF Image X Institute; University of Sydney Central Clinical School; Sydney NSW Australia
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