Delivery Modification as an Alternative to Patient Repositioning in Tomotherapy

Olivera, G.; Fitchard, E.; Reckwerdt, Paul; Ruchala, K; Mackie, T

doi:10.1007/978-3-642-59758-9_113

Cited by 18 publications

(17 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These include offline adaptive correction schemes [15][16][17][18] and online correction techniques. [19][20][21][22][23][24][25][26] Offline adaptive processes have been used to correct systematic positioning errors. 15,18 Offline replanning after imaging feedback by taking into account what has been delivered has also been proposed.…”

Section: Introductionmentioning

confidence: 99%

“…15,18 Offline replanning after imaging feedback by taking into account what has been delivered has also been proposed. 15 For online correction, both patient repositioning 1,[3][4][5]8,26 and plan adjustments 19,20,22,23,25 have been proposed. Most online correction techniques rely on figuring out the translations needed to match the images of the day to those used for planning and adjusting patient position accordingly using couch motion.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An on-line replanning scheme for interfractional variationsa)

et al. 2008

View full text Add to dashboard Cite

Ability of online adaptive replanning is desirable to correct for interfraction anatomic changes. A full-scope replanning/reoptimization with the current planning techniques takes too long to be practical. A novel online replanning strategy to correct for interfraction anatomic changes in real time is presented. The scheme consists of three steps: (1) rapidly delineating targets and organs at risk on the computed tomography of the day by modifying original planning contours using robust tools in a semiautomatic manner, (2) online segment aperture morphing (SAM) (adjusting beam/ segment apertures) by applying the spatial relationship between the planning target contour and the apertures to the new target contour, and (3) performing segment weight optimization (SWO) for the new apertures if necessary. The entire scheme was tested for direct-aperture-based IMRT on representative prostate and abdomen cases. Dose volume histograms obtained with the online scheme are practically equivalent to those obtained with full-scope reoptimization. For the days of small to moderate organ deformations, only the SAM is necessary, while for the large deformation days, both SAM and SWO are required to adequately account for the deformation. Both the SAM and SWO programs can be completed within 1 min, and the overall process can be completed within 10 min. The proposed SAM-SWO scheme is practically comparable to full-scope reoptimization, but is fast enough to be implemented for on-line adaptive replanning, enabling dose-guided RT.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An on-line replanning scheme for interfractional variationsa)

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Therefore it is useful to study the possibility of implementing some fast treatment plan modification schemes in adaptive radiotherapy. On helical tomotherapy units, delivery modification based on the binary MLC leaf delivery sinograms 3 has been proposed. In delivery modification, the original optimized beam fluence in sinogram is quickly modified to account for simple patient offsets that can be defined by six patient offset parameters ͑three for patient translation and three for patient rotation͒.…”

Section: Introductionmentioning

confidence: 99%

Fast treatment plan modification with an over-relaxed Cimmino algorithm

Jeraj

et al. 2004

Med. Phys.

View full text Add to dashboard Cite

A method to quickly modify a treatment plan in adaptive radiotherapy was proposed and studied. The method is based on a Cimmino-type algorithm in linear programming. The fast convergence speed is achieved by over-relaxing the algorithm relaxation parameter from its sufficient convergence range of ͑0, 2͒ to ͑0, ϱ͒. The algorithm parameters are selected so that the over-relaxed Cimmino ͑ORC͒ algorithm can effectively approximate an unconstrained re-optimization process in adaptive radiotherapy. To demonstrate the effectiveness and flexibility of the proposed method in adaptive radiotherapy, two scenarios with different organ motion/deformation of one nasopharyngeal case were presented with comparisons made between this method and the re-optimization method. In both scenarios, the ORC algorithm modified treatment plans have dose distributions that are similar to those given by the re-optimized treatment plans. It takes us using the ORC algorithm to finish a treatment plan modification at least three times faster than the re-optimization procedure compared.

show abstract

“…This integration of equipment on a single gantry allows for a host of verification processes. Specifically, patient registration in projection space, 14,15 delivery modification without the need for reoptimization, 16 megavoltage CT imaging ͑MVCT͒, [17][18][19][20] DV, 1,2,7 and DR 4,7-10 will be possible. The transfer matrix approach to DV and DR described previously are verification techniques for general radiotherapy and dynamic intensity modulated radiation therapy as well as tomotherapy: In principle the processes and that described in this manuscript can be used for other delivery strategies ͑e.g., those using dynamic MLCs͒.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A feasible method for clinical delivery verification and dose reconstruction in tomotherapy

et al. 2001

Self Cite

View full text Add to dashboard Cite

Delivery verification is the process in which the energy fluence delivered during a treatment is verified. This verified energy fluence can be used in conjunction with an image in the treatment position to reconstruct the full three-dimensional dose deposited. A method for delivery verification that utilizes a measured database of detector signal is described in this work. This database is a function of two parameters, radiological path-length and detector-to-phantom distance, both of which are computed from a CT image taken at the time of delivery. Such a database was generated and used to perform delivery verification and dose reconstruction. Two experiments were conducted: a simulated prostate delivery on an inhomogeneous abdominal phantom, and a nasopharyngeal delivery on a dog cadaver. For both cases, it was found that the verified fluence and dose results using the database approach agreed very well with those using previously developed and proven techniques. Delivery verification with a measured database and CT image at the time of treatment is an accurate procedure for tomotherapy. The database eliminates the need for any patient-specific, pre-or post-treatment measurements. Moreover, such an approach creates an opportunity for accurate, real-time delivery verification and dose reconstruction given fast image reconstruction and dose computation tools.

show abstract

Delivery Modification as an Alternative to Patient Repositioning in Tomotherapy

Cited by 18 publications

References 4 publications

An on-line replanning scheme for interfractional variationsa)

An on-line replanning scheme for interfractional variationsa)

Fast treatment plan modification with an over-relaxed Cimmino algorithm

A feasible method for clinical delivery verification and dose reconstruction in tomotherapy

Contact Info

Product

Resources

About