Quantifying the Dosimetric Trade-Offs When Using Intensity-Modulated Radiotherapy to Treat Concave Targets Containing Normal Tissues

Reese, Adam; Das, Shiva K.; Kirkpatrick, John P.; Marks, Lawrence B.

doi:10.1016/j.ijrobp.2008.09.044

Cited by 4 publications

(2 citation statements)

References 12 publications

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“…A previously published LPO algorithm (DeGersem et al 2001) will be used as the algorithm for MLC optimization implemented without restriction on leaf movements. The test phantom features a concave-shaped target volume that wraps around a circular organ at risk which has been used in a number of different other studies to assess IMRT and IMAT optimization (Gillis et al 2005, Mahan et al 2005, Zhang et al 2005, Oliver et al 2008, Reese et al 2009. Unconstrained IMAT plans will then be compared against each other with different optimization strategies and initial conditions.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of optimization strategies and the effect of initial conditions on IMAT optimization using a leaf position optimization algorithm

Oliver¹,

Jensen²,

Chen³

et al. 2009

Phys. Med. Biol.

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Intensity-modulated arc therapy (IMAT) is a rotational variant of intensity-modulated radiation therapy (IMRT) that can be implemented with or without angular dose rate variation. The purpose of this study is to assess optimization strategies and initial conditions using a leaf position optimization (LPO) algorithm altered for variable dose rate IMAT. A concave planning target volume (PTV) with a central cylindrical organ at risk (OAR) was used in this study. The initial IMAT arcs were approximated by multiple static beams at 5 degrees angular increments where multi-leaf collimator (MLC) leaf positions were determined from the beam's eye view to irradiate the PTV but avoid the OAR. For the optimization strategy, two arcs with arc ranges of 280 degrees and 150 degrees were employed and plans were created using LPO alone, variable dose rate optimization (VDRO) alone, simultaneous LPO and VDRO and sequential combinations of these strategies. To assess the MLC initialization effect, three single 360 degrees arc plans with different initial MLC configurations were generated using the simultaneous LPO and VDRO. The effect of changing optimization degrees of freedom was investigated by employing 3 degrees , 5 degrees and 10 degrees angular sampling intervals for the two 280 degrees , two 150 degrees and single arc plans using LPO and VDRO. The objective function value, a conformity index, a dose homogeneity index, mean dose to OAR and normal tissues were computed and used to evaluate the treatment plans. This study shows that the best optimization strategy for a concave target is to use simultaneous MLC LPO and VDRO. We found that the optimization result is sensitive to the choice of initial MLC aperture shapes suggesting that an LPO-based IMAT plan may not be able to overcome local minima for this geometry. In conclusion, simultaneous MLC leaf position and VDRO are needed with the most appropriate initial conditions (MLC positions, arc ranges and number of arcs) for IMAT.

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Section: Introductionmentioning

confidence: 99%

Evaluation of optimization strategies and the effect of initial conditions on IMAT optimization using a leaf position optimization algorithm

Oliver¹,

Jensen²,

Chen³

et al. 2009

Phys. Med. Biol.

View full text Add to dashboard Cite

show abstract

“…As a result, when sparing organs at risk, the dose is redistributed to other normal tissues, possibly causing unintended tissue toxicity. 2 , 3 Therefore, clinical trial evidence is needed to support the theoretical dosimetric superiority of IMRT for its routine application in specific clinical scenarios.…”

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confidence: 99%

Is the Use of Intensity-Modulated Radiotherapy Beneficial for Pancreatic Cancer Patients?

Park

2016

Gut Liver

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Minimising contralateral breast dose in post-mastectomy intensity-modulated radiotherapy by incorporating conformal electron irradiation

Laan

Korevaar

Dolsma

et al. 2010

Radiotherapy and Oncology

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Quantifying the Dosimetric Trade-Offs When Using Intensity-Modulated Radiotherapy to Treat Concave Targets Containing Normal Tissues

Cited by 4 publications

References 12 publications

Evaluation of optimization strategies and the effect of initial conditions on IMAT optimization using a leaf position optimization algorithm

Evaluation of optimization strategies and the effect of initial conditions on IMAT optimization using a leaf position optimization algorithm

Is the Use of Intensity-Modulated Radiotherapy Beneficial for Pancreatic Cancer Patients?

Minimising contralateral breast dose in post-mastectomy intensity-modulated radiotherapy by incorporating conformal electron irradiation

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