Respiratory Motion Tracking for Robotic Radiosurgery

Sayeh, S.; Wang, James; Main, W.; Kilby, W.; Maurer, Calvin R.

doi:10.1007/978-3-540-69886-9_2

Cited by 77 publications

(68 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…-The polynomial models traditionally used in the CyberKnife, see [4] -Our correlation model based on ε-SVR machines These correlation algorithms were developed and implemented in MATLAB. The SVR machines were built using LibSVM [8].…”

Section: Correlation Methodsmentioning

confidence: 99%

“…The polynomial models given in [4] are used to find coefficients of a linear or quadratic polynomial relating the principal directional component of motion of one LED to the principal directional component of motion of the fiducial. Additionally, the model supports breathing hysteresis by building two polynomials, one for inspiration and one for expiration.…”

Section: Correlation Methodsmentioning

confidence: 99%

“…Furthermore, the markers (currently three) are placed on the patient's chest at those points showing the greatest excursion. The currently employed correlation model is either linear, curvilinear, dual-curvilinear or a mixture of those and is based on the principal directional component of motion of each individual chest LED [4].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Correlating Chest Surface Motion to Motion of the Liver Using ε-SVR – A Porcine Study

Ernst

Martens

Schlichting

et al. 2009

Medical Image Computing and Computer-Assisted Intervention – MICCAI 2009

View full text Add to dashboard Cite

Abstract. In robotic radiosurgery, the compensation of motion of internal organs is vital. This is currently done in two phases: an external surrogate signal (usually active optical markers placed on the patient's chest) is recorded and subsequently correlated to an internal motion signal obtained using stereoscopic X-ray imaging. This internal signal is sampled very infrequently to minimise the patient's exposure to radiation. We have investigated the correlation of the external signal to the motion of the liver in a porcine study using ε-support vector regression. IR LEDs were placed on the swines' chest. Gold fiducials were placed in the swines' livers and were recorded using a two-plane X-ray system. The results show that a very good correlation model can be built using ε-SVR, in this test clearly outperforming traditional polynomial models by at least 45 and as much as 74 %. Using multiple markers simultaneously can increase the new model's accuracy.

show abstract

Section: Correlation Methodsmentioning

confidence: 99%

Section: Correlation Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Correlating Chest Surface Motion to Motion of the Liver Using ε-SVR – A Porcine Study

Ernst

Martens

Schlichting

et al. 2009

Medical Image Computing and Computer-Assisted Intervention – MICCAI 2009

View full text Add to dashboard Cite

show abstract

“…En planification inverse, l'algorithme de dosimétrie permet de régler l'orientation angulaire du robot pour que l'axe du faisceau coïncide avec le centre du volume-cible, et de calculer la pondération de chaque faisceau pour respecter la dose à délivrer à chaque point de la tumeur et la dose maximale à délivrer aux organes critiques avoisinant, (8). Dès les années 2000, les principes de la radio stéréotaxie intracrânienne ont été appliqués aux localisations extracrâniennes, pour des cibles soit non liées, soit liées à la respiration (9,10). Les repérages se font au moyen d'implantation de grains d'or pour les cibles non liées à des structures osseuses ou bien avec des diodes électroluminescentes posées sur le patient, associées à 3 caméras.…”

Section: -2-3 La Stéréotaxieunclassified

New perspectives in radiation therapy

Dubois¹

2017

IJMS

View full text Add to dashboard Cite

RESUMELes perspectives actuelles de la radiothérapie reposent à la fois sur de nouveaux concepts physiques, biologiques et sur des évolutions technologiques permanentes pour répondre à l'objectif fondamental de l'acte radiothérapique : traiter la tumeur, toute la tumeur et rien que la tumeur. Les progrès actuels et à venir concernent la précision dans la définition anatomique des volumes à traiter et des organes critiques à protéger avec l'introduction des techniques de l'imagerie dans la préparation et la réalisation du traitement au moyen de l'échographie, du PET Scan, et de l'imagerie sérielle embarquée (scanner, IRM) couplée à l'accélérateur linéaire. Les concepts modernes de la distribution de dose ont conduit au développement de la Radiothérapie tridimensionnelle de conformation et à une optimisation de la dosimétrie par les paradigmes nouveaux de la dosimétrie inverse permettant les applications de la modulation d'intensité, de la tomothérapie hélicoïdale, de la radiostéréotaxie pour des indications cliniques nouvelles auxquelles aucune thérapeutique alternative ne pouvait être proposée. Outre ces améliorations dans l'administration et la distribution de dose, la Radiothérapie se développe également dans d'autres modes de distribution : curiethérapie à débit pulsé, à haut débit de dose, ou avec implants permanents, radiothérapie intra-opératoire et aussi utilisation de rayonnements nouveaux : neutrons, protons, ions carbone. Des progrès sont également attendus avec le développement d'une évaluation biologique de la radiosensibilité des tissus tumoraux et de la radiotolérance des tissus sains permettant une adaptation permanente du fractionnement de la dose et de la dose délivrée tout au long du traitement. Enfin, des perspectives nouvelles apparaissent grâce à une meilleure conception du rôle de la radiothérapie et de sa place réelle dans le cadre d'une stratégie thérapeutique globale du cancer en fonction de chaque tumeur et de chaque patient. MOTS CLÉS :Radiothérapie de conformation -Dosimétrie inverse -Radiostéréotaxie -Curiethérapie à haut débit -Hadronthérapie. ABSTRACTNew developments and new technologies in radiation therapy are concerning the anatomical definition of the targets which are to be treated and of the critical organs which should be spared. These objectives can be reached by using modern imaging techniques: (US, PET Scan, CT Scan, MRI) allowing image-guided radiation Therapy (IGRT). Modern concepts of dose distribution (inverse dosimetry) lead to the tri-dimensional conformal Radiation Therapy (3D -CRT), intensity modulated Radiation Therapy (IMRT) and technological applications as helicoïdal tomotherapy, radiostereotaxy. New dose distribution techniques are also in progress: high dose rate (HDR), pulsed-dose-rate (PDR) brachytherapy, intraoperative Radiation Therapy and new medical applications of neutrons, protons, ions carbone. Moreover, improvements in radiation therapy administrations are expected by using biological investigations to know in real time tumor radiosensitization and...

show abstract

“…Developments in image-guided radiation therapy have led to the tracking of markers over prolonged periods of treatment which raises concern regarding the magnitude of dose delivered to patients due to imaging. 10,12 In previous work, we showed that in x-ray fluoroscopy, a relationship can be established between the tube current used and the operating tracking uncertainty defined as the determinant of the covariance matrix of the state of the system. 11 In addition, we proposed a framework for feedback of uncertainty to modulate the tube current and limit radiation dose to the patient.…”

Section: Introductionmentioning

confidence: 99%

Iso‐uncertainty control in an experimental fluoroscopy system

2014

View full text Add to dashboard Cite

Purpose: X-ray fluoroscopy remains an important imaging modality in a number of image-guided procedures due to its real-time nature and excellent spatial detail. However, the radiation dose delivered raises concerns about its use particularly in lengthy treatment procedures (>0.5 h). The authors have previously presented an algorithm that employs feedback of geometric uncertainty to control dose while maintaining a desired targeting uncertainty during fluoroscopic tracking of fiducials. The method was tested using simulations of motion against controlled noise fields. In this paper, the authors embody the previously reported method in a physical prototype and present changes to the controller required to function in a practical setting. Methods: The metric for feedback used in this study is based on the trace of the covariance of the state of the system, tr(C). The state is defined here as the 2D location of a fiducial on a plane parallel to the detector. A relationship between this metric and the tube current is first developed empirically. This relationship is extended to create a manifold that incorporates a latent variable representing the estimated background attenuation. The manifold is then used within the controller to dynamically adjust the tube current and maintain a specified targeting uncertainty. To evaluate the performance of the proposed method, an acrylic sphere (1.6 mm in diameter) was tracked at tube currents ranging from 0.5 to 0.9 mA (0.033 s) at a fixed energy of 80 kVp. The images were acquired on a Varian Paxscan 4030A (2048 × 1536 pixels, ∼100 cm source-to-axis distance, ∼160 cm source-to-detector distance). The sphere was tracked using a particle filter under two background conditions: (1) uniform sheets of acrylic and (2) an acrylic wedge. The measured tr(C) was used in conjunction with a learned manifold to modulate the tube current in order to maintain a specified uncertainty as the sphere traversed regions of varying thickness corresponding to the acrylic sheets in the background. Results: With feedback engaged, the tracking error was found to correlate well with the specified targeting uncertainty. Tracking of the fiducial was found to be robust to changes in the attenuation presented by the varying background conditions. For a desired uncertainty of 5.0 mm, comparison of the feedback framework with a comparable system employing fixed exposure demonstrated dose savings of 29%. Conclusions: This work presents a relation between a state descriptor, tr(C), the x-ray tube current used, and an estimate of the background attenuation. This relation is leveraged to modulate the tube current in order to maintain a desired geometric uncertainty during fluoroscopy. The authors' work demonstrates the use of the method in a real x-ray fluoroscopy system with physical motion against varying backgrounds. The method offers potential savings in imaging dose to patients and staff while maintaining tracking uncertainty during fluoroscopy-guided treatment procedures. C 2014 American Association of Phys...

show abstract

Respiratory Motion Tracking for Robotic Radiosurgery

Cited by 77 publications

References 32 publications

Correlating Chest Surface Motion to Motion of the Liver Using ε-SVR – A Porcine Study

Correlating Chest Surface Motion to Motion of the Liver Using ε-SVR – A Porcine Study

New perspectives in radiation therapy

Iso‐uncertainty control in an experimental fluoroscopy system

Contact Info

Product

Resources

About