Six Degrees-of-Freedom Prostate and Lung Tumor Motion Measurements Using Kilovoltage Intrafraction Monitoring

Huang, Chen-Yu; Tehrani, Joubin Nasehi; Ng, Jin Aun; Booth, Jeremy; Keall, Paul J.

doi:10.1016/j.ijrobp.2014.09.040

Cited by 60 publications

(78 citation statements)

References 27 publications

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“…An aspect of motion compensation that we have neglected in this work is the ability to detect the motion. A variety of methods have been used to monitor tumor motion in radiotherapy, including methods using ultrasound, radio‐frequency beacons, and x‐ray images . Each of these tracking methods has advantages and limitations, and the dose calculator described in this work can be used to help investigate the impact of these limitations on the delivered dose.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of TomoTherapy dose calculations with intrafractional motion and motion compensation

2017

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Purpose: Anatomical motion, both cyclical and aperiodic, can impact the dose delivered during external beam radiation. In this work, we evaluate the use of a research version of the clinical TomoTherapy â dose calculator to calculate dose with intrafraction rigid motion. We also evaluate the feasibility of a method of motion compensation for helical tomotherapy using the jaws and MLC. Methods: Treatment plans were created using the TomoTherapy treatment planning system. Dose was recalculated for several simple rigid motion traces including a 4 mm step motion applied either longitudinally or transversely, and a sinusoidal motion. The calculated dose volumes were compared to dose measurements that were performed by translating the phantom with the same motion traces used in the calculations. Measurements were made using film and ion chambers. Finally, the delivery plans were modified to compensate for the motion by sweeping the jaws for longitudinal motion and shifting the MLC leaves for transverse motion, and the calculations and measurements were repeated. Results: A transverse step motion shifted the dose that was delivered after the step occurred, but otherwise did not impact the dose distribution. Film measurements agreed with dose calculations to within 2%/2 mm for 99% of dose points within the 50% isodose line. A shift in the MLC leaf delivery pattern successfully compensated for the step motion to within the 3 mm accuracy allowed by the finite leaf widths. A longitudinal step motion impacted the dose in the interior of the target volume to a degree that was dependent on the planning field width and step size. Film measurements agreed with dose calculations to within 2%/2 mm for 98% of dose points within the 50% isodose line. Shifts in the jaw position successfully compensated for the longitudinal step motion. Sinusoidal (breathinglike) motion was also studied, with similar results. Conclusions: A research version of the clinical TomoTherapy dose calculator has been shown to accurately calculate the dose from treatment plans delivered in the presence of arbitrary rigid motion. Modifications to the delivery plan using jaw and MLC leaf shifts that follow the motion can successfully compensate for the target motion.

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Section: Discussionmentioning

confidence: 99%

Evaluation of TomoTherapy dose calculations with intrafractional motion and motion compensation

2017

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“…Also, for all the treatment fractions, patient anatomy has been assumed to be the same as at treatment planning. Rotational as well as deformation components of the motion can substantially affect the dose delivery during the treatments, this also needs to be investigated [23,24]. Additionally, as noted earlier, another limitation is that the dose reconstruction system assumes that the prostate and surrounding OARs move together rigidly.…”

Section: Discussionmentioning

confidence: 99%

Quantification of intrafraction prostate motion and its dosimetric effect on VMAT

Juneja

Colvill

Kneebone

et al. 2017

Australas Phys Eng Sci Med

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Compliance with ethical standards Conflict of interestRoyal North Shore Hospital has a collaborative research agreement with Varian Medical Systems to support Calypso® and Kilovoltage intrafraction monitoring (KIM) clinical trials. PK holds part ownership of the patent, between Stanford University and Varian Medical Systems, on KIM technology. Ethical approvalAll procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.Intrafraction prostate motion degrades the accuracy of radiation therapy (RT) delivery. Whilst a number of metrics in the literature have been used to quantify intrafraction prostate motion, it has not been established whether these metrics reflect the effect of motion on the RT dose delivered to the patients. In this study, prostate motion during volumetric modulated arc therapy (VMAT) treatment of 18 patients and a total of 294 fractions was quantified through novel metrics as well as those available in the literature. The impact of the motion on VMAT dosimetry was evaluated using these metrics and dose reconstructions based on a previously validated and published method. The dosimetric impact of the motion on planning target volume (PTV) and clinical target volume (CTV) coverage and organs at risk (OARs) was correlated with the motion metrics, using the coefficient of determination (R 2 ), to evaluate their utility. Action level threshold for the prostate motion metric that best described the dosimetric impact on the PTV D95% was investigated through iterative regression analysis. The average (range) of the mean motion for the patient cohort was 1.5 mm (0.3-9.9 mm). A number of motion metrics were found to be strongly correlated with PTV D95%, the range of R 2 was 0.43-0.81. For all the motion measures, correlations with CTV D99% (range of R 2 was 0.12-0.62), rectum V65% (range of R 2 was 0.33-0.58) and bladder V65% (range of R 2 was 0.51-0.69) were not as strong as for PTV D95%. The mean of the highest 50% of motion metric was one of the best indicator of dosimetric impact on PTV D95%. Action level threshold value for this metric was found to be 3.0 mm. For an individual fraction, when the metric value was greater than 3.0 mm then the PTV D95% was reduced on average by 6.2%. This study demonstrated that several motion metrics are well correlated with the dosimetric impact (PTV D95%) of individual fraction prostate motion on VMAT delivery and could be used for treatment course adaptation.

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“…Centers are increasingly using electromagnetic transponders to assess motion in real time (14,15), and additional data are becoming available through intrafraction kilovoltage imaging (16). Over time this will yield the large datasets of intrafraction displacement data required to enable development of the appropriate models.…”

Section: Discussionmentioning

confidence: 99%

Sparing Healthy Tissue and Increasing Tumor Dose Using Bayesian Modeling of Geometric Uncertainties for Planning Target Volume Personalization

Herschtal

Marvelde

Mengersen

et al. 2015

International Journal of Radiation Oncology*Biology*Physics

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Six Degrees-of-Freedom Prostate and Lung Tumor Motion Measurements Using Kilovoltage Intrafraction Monitoring

Cited by 60 publications

References 27 publications

Evaluation of TomoTherapy dose calculations with intrafractional motion and motion compensation

Evaluation of TomoTherapy dose calculations with intrafractional motion and motion compensation

Quantification of intrafraction prostate motion and its dosimetric effect on VMAT

Sparing Healthy Tissue and Increasing Tumor Dose Using Bayesian Modeling of Geometric Uncertainties for Planning Target Volume Personalization

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