BACKGROUND Online adaptive radiotherapy(oART)has demonstrated improved target volume coverage and enhanced sparing of surrounding pelvic organs through daily reoptimization based on pretreatment imaging.Recently,itera...BACKGROUND Online adaptive radiotherapy(oART)has demonstrated improved target volume coverage and enhanced sparing of surrounding pelvic organs through daily reoptimization based on pretreatment imaging.Recently,iterative cone-beam computed tomography(iCBCT)has been integrated into oART workflows,facilitating precise daily adaptation.However,the dosimetric consequences of intra-fractional variations for clinical target volume(CTV)and organs at risk(OARs)remain insufficiently characterized.AIM To investigate intra-fractional CTV and OARs variation and their impact on iCBCT guided daily oART for postoperative cervical and endometrial cancer.METHODS Seventeen patients treated with daily postoperative iCBCT guided oART with rigorous bladder and rectal preparation protocols were enrolled.CTV and OARs were contoured on pre-and post-treatment iCBCT scans.The average surface distance(ASD),dice similarity coefficient(DSC),and 95%Hausdorff distance(HD)were utilized to evaluate the difference between pre-and post-treatment structures.Dosimetric outcomes for the pretreatment target volumes and OARs were recalculated using posttreatment contours to assess the impact of intrafractional variation.RESULTS A total of 434 treatment fractions were analyzed,with an average interval time of 22 minutes between two iCBCT scans.Minimal variations were observed in the bladder,rectum,and CTV both pre-and post-treatment,with DSC exceeding 0.8.The vaginal CTV exhibited centroid deviations of 0.46 mm anteriorly,0.11 mm laterally,and 0.58 mm superiorly,along with ASD of 1.69 mm and 95%HD of 6.42 mm.Weak correlations were observed between vaginal CTV posterior-anterior centroid deviations and rectal superior-inferior deviations(P=0.017).Minimal dosimetric differences were observed pre-and post-treatment,with V100%for the adapted plan of nodal CTV being 99.94%vs 99.08%and vaginal CTV being 99.97%vs 98.66%.CONCLUSION Daily iCBCT-guided oART with strict bladder and rectal preparation effectively compensates for intra-fractional variations,maintaining CTV coverage and OAR sparing across all treatment fractions.展开更多
Changes in the tumour position due to inter and intra-fractional motion introduce uncertainty in IMRT delivery. In this work, we experimentally evaluated the effect of inter and intra-fractional motion uncertainties i...Changes in the tumour position due to inter and intra-fractional motion introduce uncertainty in IMRT delivery. In this work, we experimentally evaluated the effect of inter and intra-fractional motion uncertainties in the IMRT delivery. A lung patient was planned with rive field dynamic IMRT for a total dose of60 Gy in 30 fractions using 6 MV photon beam at a dose rate of 400 MU/min. The plan was delivered on varian CL2100 CD linear accelerator with millennium 120 MLC for a single fraction and measured using IMRT Matri XX placed on Quasar motion platform, aligned with respect to isocentre for planar as well as point dose measurements. This measurement was summated for 30 fractions and taken as a reference. 30 measurements were performed for each inter-fractional, intra-fractional and combined effect. The setup errors(Mean+SD) used to simulate the inter-fractional displacements were RL:-0.10+0.27 mm, SI: 0.17+0.45 mm, AP:-0.04+0.38 mm and Rot: 0.02+0.86 degree. The intra-fractional motion was simulated using the motion platform parallel to the MLC leaf motion, for an amplitude of 1 cm and a period of 4 s. The planner fluence of inter, intra-fractional motion and combination of both was analyzed against the reference using gamma criteria of 3%/3 mm. Similarly, the point dose measurements were also compared. The maximum deviation in point dose during a single fraction was-3.8%, 3.1% and-5.9% for inter-fractional, intra-fractional and combined respectively. The same resulted in deviation of-0.4%,-0.3% and 0.1% respectively when summated for 30 fractions.The percentage of pixels failing the gamma criteria during a single fraction was28.0%, 16.4% and 28.5% for inter-fractional, intra-fractional and combined respectively. The same revealed 11.4%, 12.4% and 19.2% respectively when summated. Though the point dose deviations were nullified over 30 fractions, the planner fluence variation was observed to be considerable.展开更多
The aim of this study is to propose a novel system that has an ability to detect intra-fractional motion during radiotherapy treatment in real-time using three-dimensional surface taken by a depth camera, Microsoft Ki...The aim of this study is to propose a novel system that has an ability to detect intra-fractional motion during radiotherapy treatment in real-time using three-dimensional surface taken by a depth camera, Microsoft Kinect v1. Our approach introduces three new aspects for three-dimensional surface tracking in radiotherapy treatment. The first aspect is a new algorithm for noise reduction of depth values. Ueda’s algorithm was implemented and enabling a fast least square regression of depth values. The second aspect is an application for detection of patient’s motion at multiple points in thracoabdominal regions. The third aspect is an estimation of three-dimensional surface from multiple depth values. For evaluation of noise reduction by Ueda’s algorithm, two respiratory patterns are measured by the Kinect as well as a laser range meter. The resulting cross correlation coefficients between the laser range meter and the Kinect were 0.982 for abdominal respiration and 0.995 for breath holding. Moreover, the mean cross correlation coefficients between the signals of our system and the signals of Anzai with respect to participant’s respiratory motion were 0.90 for thoracic respiration and 0.93 for abdominal respiration, respectively. These results proved that the performance of the developed system was comparable to existing motion monitoring devices. Reconstruction of three-dimensional surface also enabled us to detect the irregular motion and breathing arrest by comparing the averaged depth with predefined threshold values.展开更多
The purpose of this study was to investigate the ability of a management system (Delivery Analysis: DA) to detect intrafractional motion during intensity-modulated radiation therapy (IMRT) in tomotherapy mode. Tomothe...The purpose of this study was to investigate the ability of a management system (Delivery Analysis: DA) to detect intrafractional motion during intensity-modulated radiation therapy (IMRT) in tomotherapy mode. Tomotherapy has made it possible to manage internal movements during treatment using software DA, which quantifies using the information of the passing dose obtained during the radiation treatment of patients. First, three treatment plans for the test were created (lumbar spine, prostate, and femur). Second, a pelvis phantom was moved in the X, Y, and Z directions, and a sinogram was acquired. The magnitudes of the movements were 3 mm, 5 mm, and 10 mm, respectively. Finally, the ability of DA to detect the motion was evaluated by comparing the sinogram obtained by moving the phantom with a reference sinogram obtained without movement. The sensitivity of DA could be detected with a shift amount of 3 mm (gamma analysis tolerance 0.3 mm/0.3%). The average gamma analysis of each direction at 0.3 mm/0.3% tolerance at each treatment site was 96.1% for the prostate, 93.5% for the lumbar spine, and 94.4% for the femur. Additionally, the average gamma pass rate results for the pelvic phantom in the X, Y, Z directions for a 10 mm shift were 96.2%, 96.3%, and 95.9%, respectively. DA is a powerful tool with high detection sensitivity and ability to detect body movement during treatment.展开更多
Aim: To analyze the inter-fraction, intra-fraction uncertainties and to verify the delivered total dose with planned dose in the combined intracavitary-interstitial brachytherapy of gynaecological cancer patients usin...Aim: To analyze the inter-fraction, intra-fraction uncertainties and to verify the delivered total dose with planned dose in the combined intracavitary-interstitial brachytherapy of gynaecological cancer patients using microMOSFET in-vivo dosimeter. Materials and Methods: Between May 2014 and March 2016, 22 patients who underwent brachytherapy treatments with an applicator combination of CT/MR compatible tandem, ring and Syed-Neblett template-guided rigid needles were included in this study. Specially designed microMOSFET, after calibration, was used to analyze the variations in dosimetry of combined intracavitary-interstitial application. Results: The standard deviation for Inter-fraction variation among 22 combined intracavitary interstitial applications ranged between 0.86% and 10.92%. When compared with the first fraction dose, the minimum and maximum dose variations were −9.5% and 26.36%, respectively. However, the mean doses varied between −5.95% and 14.49%. Intra-fraction variation, which is the difference of TPS calculated dose with first fraction microMOSFET-measured dose ranges from −6.77% to 8.68%. The variations in the delivered total mean dose in 66 sessions with planned doses were −3.09% to 10.83%. Conclusions: It is found that there was a gradual increase in microMOSFET measured doses as compared to the first fraction with that of subsequent fractions in 19 out of 22 applications. Tumor deformation and edema may be the influencing factors, but the applicator movements played a major role for the variations. We find that the microMOSFET is an easy and reliable system for independent verification of uncertainties during ICBT-ISBT treatments.展开更多
基金Supported by the National Key R&D Program of China,No.2022YFC2407100 and No.2022YFC2407101the National High Level Hospital Clinical Research Funding,No.2022-PUMCH-B-127.
文摘BACKGROUND Online adaptive radiotherapy(oART)has demonstrated improved target volume coverage and enhanced sparing of surrounding pelvic organs through daily reoptimization based on pretreatment imaging.Recently,iterative cone-beam computed tomography(iCBCT)has been integrated into oART workflows,facilitating precise daily adaptation.However,the dosimetric consequences of intra-fractional variations for clinical target volume(CTV)and organs at risk(OARs)remain insufficiently characterized.AIM To investigate intra-fractional CTV and OARs variation and their impact on iCBCT guided daily oART for postoperative cervical and endometrial cancer.METHODS Seventeen patients treated with daily postoperative iCBCT guided oART with rigorous bladder and rectal preparation protocols were enrolled.CTV and OARs were contoured on pre-and post-treatment iCBCT scans.The average surface distance(ASD),dice similarity coefficient(DSC),and 95%Hausdorff distance(HD)were utilized to evaluate the difference between pre-and post-treatment structures.Dosimetric outcomes for the pretreatment target volumes and OARs were recalculated using posttreatment contours to assess the impact of intrafractional variation.RESULTS A total of 434 treatment fractions were analyzed,with an average interval time of 22 minutes between two iCBCT scans.Minimal variations were observed in the bladder,rectum,and CTV both pre-and post-treatment,with DSC exceeding 0.8.The vaginal CTV exhibited centroid deviations of 0.46 mm anteriorly,0.11 mm laterally,and 0.58 mm superiorly,along with ASD of 1.69 mm and 95%HD of 6.42 mm.Weak correlations were observed between vaginal CTV posterior-anterior centroid deviations and rectal superior-inferior deviations(P=0.017).Minimal dosimetric differences were observed pre-and post-treatment,with V100%for the adapted plan of nodal CTV being 99.94%vs 99.08%and vaginal CTV being 99.97%vs 98.66%.CONCLUSION Daily iCBCT-guided oART with strict bladder and rectal preparation effectively compensates for intra-fractional variations,maintaining CTV coverage and OAR sparing across all treatment fractions.
基金Department of Science&Technology,Government of lndiagrant sponsor:IR/SO/LS 02/2003
文摘Changes in the tumour position due to inter and intra-fractional motion introduce uncertainty in IMRT delivery. In this work, we experimentally evaluated the effect of inter and intra-fractional motion uncertainties in the IMRT delivery. A lung patient was planned with rive field dynamic IMRT for a total dose of60 Gy in 30 fractions using 6 MV photon beam at a dose rate of 400 MU/min. The plan was delivered on varian CL2100 CD linear accelerator with millennium 120 MLC for a single fraction and measured using IMRT Matri XX placed on Quasar motion platform, aligned with respect to isocentre for planar as well as point dose measurements. This measurement was summated for 30 fractions and taken as a reference. 30 measurements were performed for each inter-fractional, intra-fractional and combined effect. The setup errors(Mean+SD) used to simulate the inter-fractional displacements were RL:-0.10+0.27 mm, SI: 0.17+0.45 mm, AP:-0.04+0.38 mm and Rot: 0.02+0.86 degree. The intra-fractional motion was simulated using the motion platform parallel to the MLC leaf motion, for an amplitude of 1 cm and a period of 4 s. The planner fluence of inter, intra-fractional motion and combination of both was analyzed against the reference using gamma criteria of 3%/3 mm. Similarly, the point dose measurements were also compared. The maximum deviation in point dose during a single fraction was-3.8%, 3.1% and-5.9% for inter-fractional, intra-fractional and combined respectively. The same resulted in deviation of-0.4%,-0.3% and 0.1% respectively when summated for 30 fractions.The percentage of pixels failing the gamma criteria during a single fraction was28.0%, 16.4% and 28.5% for inter-fractional, intra-fractional and combined respectively. The same revealed 11.4%, 12.4% and 19.2% respectively when summated. Though the point dose deviations were nullified over 30 fractions, the planner fluence variation was observed to be considerable.
文摘The aim of this study is to propose a novel system that has an ability to detect intra-fractional motion during radiotherapy treatment in real-time using three-dimensional surface taken by a depth camera, Microsoft Kinect v1. Our approach introduces three new aspects for three-dimensional surface tracking in radiotherapy treatment. The first aspect is a new algorithm for noise reduction of depth values. Ueda’s algorithm was implemented and enabling a fast least square regression of depth values. The second aspect is an application for detection of patient’s motion at multiple points in thracoabdominal regions. The third aspect is an estimation of three-dimensional surface from multiple depth values. For evaluation of noise reduction by Ueda’s algorithm, two respiratory patterns are measured by the Kinect as well as a laser range meter. The resulting cross correlation coefficients between the laser range meter and the Kinect were 0.982 for abdominal respiration and 0.995 for breath holding. Moreover, the mean cross correlation coefficients between the signals of our system and the signals of Anzai with respect to participant’s respiratory motion were 0.90 for thoracic respiration and 0.93 for abdominal respiration, respectively. These results proved that the performance of the developed system was comparable to existing motion monitoring devices. Reconstruction of three-dimensional surface also enabled us to detect the irregular motion and breathing arrest by comparing the averaged depth with predefined threshold values.
文摘The purpose of this study was to investigate the ability of a management system (Delivery Analysis: DA) to detect intrafractional motion during intensity-modulated radiation therapy (IMRT) in tomotherapy mode. Tomotherapy has made it possible to manage internal movements during treatment using software DA, which quantifies using the information of the passing dose obtained during the radiation treatment of patients. First, three treatment plans for the test were created (lumbar spine, prostate, and femur). Second, a pelvis phantom was moved in the X, Y, and Z directions, and a sinogram was acquired. The magnitudes of the movements were 3 mm, 5 mm, and 10 mm, respectively. Finally, the ability of DA to detect the motion was evaluated by comparing the sinogram obtained by moving the phantom with a reference sinogram obtained without movement. The sensitivity of DA could be detected with a shift amount of 3 mm (gamma analysis tolerance 0.3 mm/0.3%). The average gamma analysis of each direction at 0.3 mm/0.3% tolerance at each treatment site was 96.1% for the prostate, 93.5% for the lumbar spine, and 94.4% for the femur. Additionally, the average gamma pass rate results for the pelvic phantom in the X, Y, Z directions for a 10 mm shift were 96.2%, 96.3%, and 95.9%, respectively. DA is a powerful tool with high detection sensitivity and ability to detect body movement during treatment.
文摘Aim: To analyze the inter-fraction, intra-fraction uncertainties and to verify the delivered total dose with planned dose in the combined intracavitary-interstitial brachytherapy of gynaecological cancer patients using microMOSFET in-vivo dosimeter. Materials and Methods: Between May 2014 and March 2016, 22 patients who underwent brachytherapy treatments with an applicator combination of CT/MR compatible tandem, ring and Syed-Neblett template-guided rigid needles were included in this study. Specially designed microMOSFET, after calibration, was used to analyze the variations in dosimetry of combined intracavitary-interstitial application. Results: The standard deviation for Inter-fraction variation among 22 combined intracavitary interstitial applications ranged between 0.86% and 10.92%. When compared with the first fraction dose, the minimum and maximum dose variations were −9.5% and 26.36%, respectively. However, the mean doses varied between −5.95% and 14.49%. Intra-fraction variation, which is the difference of TPS calculated dose with first fraction microMOSFET-measured dose ranges from −6.77% to 8.68%. The variations in the delivered total mean dose in 66 sessions with planned doses were −3.09% to 10.83%. Conclusions: It is found that there was a gradual increase in microMOSFET measured doses as compared to the first fraction with that of subsequent fractions in 19 out of 22 applications. Tumor deformation and edema may be the influencing factors, but the applicator movements played a major role for the variations. We find that the microMOSFET is an easy and reliable system for independent verification of uncertainties during ICBT-ISBT treatments.
