https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44516 95% of fractions were successfully delivered. The secondary outcomes were (1) the improvement in beam-target geometric alignment, (2) the improvement in dosimetric coverage of the prostate and avoidance of critical structures, and (3) no acute grade ≥3 genitourinary or gastrointestinal toxicity. Results: All 858 planned fractions were successfully delivered with MLC tracking, demonstrating the primary outcome of feasibility (P < .001). MLC tracking improved the beam-target geometric alignment from 1.4 to 0.90 mm (root-mean-square error). MLC tracking improved the dosimetric coverage of the prostate and reduced the daily variation in dose to critical structures. No acute grade ≥3 genitourinary or gastrointestinal toxicity was observed. Conclusions: Electromagnetic-guided MLC tracking radiation therapy for prostate cancer is feasible. The patients received improved geometric targeting and delivered dose distributions that were closer to those planned than they would have received without electromagnetic-guided MLC tracking. No significant acute toxicity was observed.]]> Wed 09 Nov 2022 10:02:12 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33853 Wed 04 Sep 2019 10:04:12 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25773 Tue 16 Mar 2021 10:50:09 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34638 Patient: A patient with prostate adenocarcinoma undergoing SBRT with 36.25 Gy, delivered in 5 fractions was enrolled in the study. 6DoF KIM technology: 2D positions of three implanted gold markers in each of the kV images (125 kV, 10 mA at 11 Hz) were acquired continuously during treatment. The 2D → 3D target position estimation was based on a probability distribution function. The 3D → 6DoF target rotation was calculated using an iterative closest point algorithm. The accuracy and precision of the KIM method was measured by comparing the real-time results with kV-MV triangulation. Results: Of the five treatment fractions, KIM was utilised successfully in four fractions. The intrafraction prostate motion resulted in three couch shifts in two fractions when the prostate motion exceeded the pre-set action threshold of 2 mm for more than 5 s. KIM translational accuracy and precision were 0.3 ± 0.6 mm, −0.2 ± 0.3 mm and 0.2 ± 0.7 mm in the Left-Right (LR), Superior-Inferior (SI) and Anterior-Posterior (AP) directions, respectively. The KIM rotational accuracy and precision were 0.8° ± 2.0°, −0.5° ± 3.3° and 0.3° ± 1.6° in the roll, pitch and yaw directions, respectively. Conclusion: This treatment represents, to the best of our knowledge, the first time a cancer patient’s tumour position and rotation have been monitored in real-time during treatment. The 6 DoF KIM system has sub-millimetre accuracy and precision in all three translational axes, and less than 1° accuracy and 4° precision in all three rotational axes.]]> Thu 24 Mar 2022 11:35:51 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48039 Error). For simulated field size errors, the RMS_Error was 0.47 cm² and field shape changes were detected for random errors with standard deviation ≥ 2.5 mm. For clinical lung SABR deliveries, field location errors of 1.6 mm (parallel MLC motion) and 4.9 mm (perpendicular) were measured (expressed as a full-width-half-maximum). The mean and standard deviation of the errors in field size and shape were 0.0 ± 0.3 cm² and 0.3 ± 0.1 (expressed as a translation-invariant normalized RMS). No correlation was observed between geometric errors during each treatment fraction and dosimetric errors in the reconstructed dose to the target volume for this cohort of patients. Conclusion: A system for real-time delivery verification has been developed for MLC tracking using time-resolved EPID imaging. The technique has been tested offline in phantom-based deliveries and clinical patient deliveries and was used to independently verify the geometric accuracy of the MLC during MLC tracking radiotherapy.]]> Thu 23 Mar 2023 10:25:03 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33046 Thu 03 Feb 2022 12:19:33 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:43579 4DCBCT) can complement existing 4DCT-based methods (CTVI^4DCT) to track lung function changes over a course of lung cancer radiation therapy. However, the accuracy of CTVI^4DCBCT needs to be assessed since anatomic 4DCBCT has demonstrably poor image quality and small field of view (FOV) compared to treatment planning 4DCT. We perform a direct comparison between short interval CTVI^4DCBCT and CTVI^4DCT pairs to understand the patient specific image quality factors affecting the intermodality CTVI reproducibility in the clinic. Methods and materials: We analysed 51 pairs of 4DCBCT and 4DCT scans acquired within 1 day of each other for nine lung cancer patients. To assess the impact of image quality, CTVIs were derived from 4DCBCT scans reconstructed using both standard Feldkamp-Davis-Kress backprojection (CTVI4DCBCT/FDK) and an iterative McKinnon-Bates Simultaneous Algebraic Reconstruction Technique (CTVI4DCBCT/MKBSART). Also, the influence of FOV was assessed by deriving CTVIs from 4DCT scans that were cropped to a similar FOV as the 4DCBCT scans (CTVI4DCT/crop), or uncropped (CTVI4DCT/uncrop). All CTVIs were derived by performing deformable image registration (DIR) between the exhale and inhale phases and evaluating the Jacobian determinant of deformation. Reproducibility between corresponding CTVI^4DCBCT and CTVI^4DCT pairs was quantified using the voxel-wise Spearman rank correlation and the Dice similarity coefficient (DSC) for ventilation defect regions (identified as the lower quartile of ventilation values). Mann–Whitney U-tests were applied to determine statistical significance of each reconstruction and cropping condition. Results: The (mean ± SD) Spearman correlation between CTVIRDCBCT/FDK and CTVI4DCT/uncrop was 0.60 ± 0.23 (range −0.03–0.88) and the DSC was 0.64 ± 0.12 (0.34–0.83). By comparison, correlations between CTVI4DCBCT/MKBSART and CTVI4DCTuncrop showed a small but statistically significant improvement with = 0.64 ± 0.20 (range 0.06–0.90, P = 0.03) and DSC = 0.66 ± 0.13 (0.31–0.87, P = 0.02). Intermodal correlations were noted to decrease with an increasing fraction of lung truncation in 4DCBCT relative to 4DCT, albeit not significantly (Pearson correlation R = 0.58, P = 0.002). Conclusions: This study demonstrates that DIR based CTVIs derived from 4DCBCT can exhibit reasonable to good voxel-level agreement with CTVIs derived from 4DCT. These correlations outperform previous cross-modality comparisons between 4DCT-based ventilation and nuclear medicine. The use of 4DCBCT scans with iterative reconstruction and minimal lung truncation is recommended to ensure better reproducibility between 4DCBCT- and 4DCT-based CTVIs.]]> Mon 26 Sep 2022 10:30:30 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33870 Mon 21 Jan 2019 10:42:48 AEDT ]]>