Direct aperture optimization–based intensity-modulated radiotherapy for whole breast irradiation

Ahunbay, E; Chen, Guang‐Pei; Thatcher, Steven; Jursinic, Paul A.; White, Julia; Albano, Katherine; Li, X. Allen

doi:10.1016/j.ijrobp.2006.11.036

Cited by 57 publications

(65 citation statements)

References 29 publications

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“…Among the hybrid arms, the 70:30 arm showed a statistically significant CI of 0·81 compared with 0·45, 0·46 and 0·26 for the 60:40, 70:30 and 80:20 and conventional arms, respectively. As evident in other comparative studies, 13,16,20,[48][49][50] IMRT shows greater dose conformity to target structures with our results further reflected in comparative hybrid studies. 17,18,28,51 When considering the dose homogeneity across the PTV boost , the HI indicates that the hybrid technique creates a more homogenous dose at 0·15 for all arms compared with 0·18 with the conventional plan.…”

Section: Discussionsupporting

confidence: 86%

Hybrid intensity-modulated radiation therapy (IMRT) simultaneous integrated boost (SIB) technique versus three-dimensional (3D) conformal radiotherapy with SIB for breast radiotherapy: a planning comparison

et al. 2016

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Aim: This study aims to compare conventional simultaneous integrated boost (SIB) planning technique with a hybrid SIB intensity-modulated radiation therapy (IMRT) technique with varying open tangent to IMRT field dose ratios. Furthermore, we investigated which of the dose ratios proves the most favourable as a class solution across a sample. Methods:In total, 15 patients with conventional SIB treatment plans were re-planned with hybrid SIB IMRT technique using three differing open field:IMRT dose ratios, that is, 80:20, 70:30 and 60:40. Plans were compared using dosimetric comparison of organs at risk (OARs) and homogeneity and conformity indexes across target structures.Results: All hybrid plans reduced dose maximums and showed a reduction of high doses to both lungs but increased lower doses, that is, V5, with similar results discovered for the heart. Contralateral breast dose was shown to decrease V5 and V1 measures by hybrid arms, whereas increasing the V2. Left anterior descending artery dose and non-irradiated structures were reduced by all hybrid arms. The homogeneity and conformity increased across all hybrid arms. Qualitative assessment of all plans also favoured hybrid plans.Findings: Hybrid plans produced superior dose conformity, homogeneity, reduced dose maximums and showed an improvement in most OAR parameters. The 70:30 hybrid technique exhibited greater benefits as a class solution to the sample than conventional plans due to superior dose conformity and homogeneity to target volumes.

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Section: Discussionsupporting

confidence: 86%

Hybrid intensity-modulated radiation therapy (IMRT) simultaneous integrated boost (SIB) technique versus three-dimensional (3D) conformal radiotherapy with SIB for breast radiotherapy: a planning comparison

et al. 2016

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“…The number of segments for DAO was approximately 45% segments less than those for beamlet optimizer, this is in contrast to the findings of Van Asselen et al (4) who was the only group reported an increase in segments using DMPO for breast IMRT. In another study DAO-IMRT plans for 15 breast cancer patients in supine (10 patients) and prone (5 patients) positions with a goal of uniform dose coverage of the whole breast were designed (20) . These DAO-IMRT plans were compared with standard IMRT using beamlet optimization and conventional 3D-CRT plans using wedges.…”

Section: Discussionmentioning

confidence: 99%

“…In this TPS, the one-step optimization is referred to as the direct machine parameter optimization (DMPO), and the twostep method is referred to as the intensity modulation (IM). From a study of 11 head-and-neck plans, Jones and Williams (18) found that fewer segments were used in DMPO plans than corresponding IM plans.…”

Section: Shepard Et Almentioning

confidence: 99%

“…They found no significant reduction in MUs, but a reduction in the number of segments. As well, Ahunbay et al (20) compared the DAO method in the Panther TPS and the two-step optimization in the XiO CMS TPS for ten cases of whole breast treatment. They observed that the total number of MUs for DAO plans were approximately 60% less than those of two-step optimization IMRT plans.…”

Section: Shepard Et Almentioning

confidence: 99%

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Clinical and Plan Complexity Effects of Using Direct Aperture Optimization in Breast, Head and Neck IMRT Treatment

2016

Egypt. J. Biophys. Biomed. Engng.

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O INVESTIGATE the planning complexity and dosimetric impacts of direct aperture optimization (DAO) in IMRT treatment of breast, head and neck (H/N) cancers.Three breast and five H/N patients were planned using the beamlet optimizer in Elekta-Xio © ver 4.6 IMRT treatment planning system. Based on our experience in beamlet IMRT optimization, breast PTVs were prescribed to 50 Gy with 2 fields. While PTVs in H/N plans were prescribed to 70 Gy delivered by 7 fields.. In all plans, fields were set to be equally spaced. All cases were re-planed using Direct Aperture optimizer (DAO) in Prowess Panther © ver 5.01 IMRT planning system at same configurations and dose constraints. Plans were evaluated according to ICRU criteria, number of segments, number of monitor units and planning time.For H/N plans, the dose that covers 95% (D 95 ) from PTV was 0.8% on average for plans done using beamlet optimizer more than that done using DAO, while D98%, D50% and D2% were higher in DAO plans than in beamlet optimizer by about 3%, 1%, and 2.2 %, respectively. For OAR, results showed an improvement in lung sparing in plans done using beamlet optimizer where V20 was lower by 12%. While DAO improved heart sparing than beamlet optimizer as V20 was lower 12%. These results achied using around less 45% segments number and 50% monitor units number as well.In DAO H/N plans, the near maximum dose (D 2 ) and the dose that covers 95% (D 95 ) of PTV has improved by 4% in DAO. For organs at risk (OAR), DAO reduced the volume covered by 30% (V 30 ) inspinal cord, right parotid, and left parotid by 60%, 54%, and 53% respectively. This considerable dosimetric quality improvement achieved using 25% less planning time and lower number of segments and monitor units by 46% and 51%, respectively.

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“…[4][5][6][7] Most published DAO methods begin the optimization process using a beamlet description of the beam and perform a beamlet optimization for a number of iterations. The algorithm then chooses candidate apertures after sequencing the intensity distributions and performs further optimization on this relatively large number of apertures (typically at least 5-10 per field).…”

Section: Introductionmentioning

confidence: 99%

Inverse‐optimized 3D conformal planning: Minimizing complexity while achieving equivalence with beamlet IMRT in multiple clinical sites

et al. 2012

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Purpose: Inverse planned intensity modulated radiation therapy (IMRT) has helped many centers implement highly conformal treatment planning with beamlet-based techniques. The many comparisons between IMRT and 3D conformal (3DCRT) plans, however, have been limited because most 3DCRT plans are forward-planned while IMRT plans utilize inverse planning, meaning both optimization and delivery techniques are different. This work avoids that problem by comparing 3D plans generated with a unique inverse planning method for 3DCRT called inverse-optimized 3D (IO-3D) conformal planning. Since IO-3D and the beamlet IMRT to which it is compared use the same optimization techniques, cost functions, and plan evaluation tools, direct comparisons between IMRT and simple, optimized IO-3D plans are possible. Though IO-3D has some similarity to direct aperture optimization (DAO), since it directly optimizes the apertures used, IO-3D is specifically designed for 3DCRT fields (i.e., 1-2 apertures per beam) rather than starting with IMRT-like modulation and then optimizing aperture shapes. The two algorithms are very different in design, implementation, and use. The goals of this work include using IO-3D to evaluate how close simple but optimized IO-3D plans come to nonconstrained beamlet IMRT, showing that optimization, rather than modulation, may be the most important aspect of IMRT (for some sites). Methods: The IO-3D dose calculation and optimization functionality is integrated in the in-house 3D planning/optimization system. New features include random point dose calculation distributions, costlet and cost function capabilities, fast dose volume histogram (DVH) and plan evaluation tools, optimization search strategies designed for IO-3D, and an improved, reimplemented edge/octree calculation algorithm. The IO-3D optimization, in distinction to DAO, is designed to optimize 3D conformal plans (one to two segments per beam) and optimizes MLC segment shapes and weights with various user-controllable search strategies which optimize plans without beamlet or pencil beam approximations. IO-3D allows comparisons of beamlet, multisegment, and conformal plans optimized using the same cost functions, dose points, and plan evaluation metrics, so quantitative comparisons are straightforward. Here, comparisons of IO-3D and beamlet IMRT techniques are presented for breast, brain, liver, and lung plans. Results: IO-3D achieves high quality results comparable to beamlet IMRT, for many situations. Though the IO-3D plans have many fewer degrees of freedom for the optimization, this work finds that IO-3D plans with only one to two segments per beam are dosimetrically equivalent (or nearly so) to the beamlet IMRT plans, for several sites. IO-3D also reduces plan complexity significantly. Here, monitor units per fraction (MU/Fx) for IO-3D plans were 22%-68% less than that for the 1 cm Â 1 cm beamlet IMRT plans and 72%-84% than the 0.5 cm Â 0.5 cm beamlet IMRT plans. Conclusions: The unique IO-3D algorithm illustrates that inverse planning can achieve ...

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Direct aperture optimization–based intensity-modulated radiotherapy for whole breast irradiation

Cited by 57 publications

References 29 publications

Hybrid intensity-modulated radiation therapy (IMRT) simultaneous integrated boost (SIB) technique versus three-dimensional (3D) conformal radiotherapy with SIB for breast radiotherapy: a planning comparison

Hybrid intensity-modulated radiation therapy (IMRT) simultaneous integrated boost (SIB) technique versus three-dimensional (3D) conformal radiotherapy with SIB for breast radiotherapy: a planning comparison

Clinical and Plan Complexity Effects of Using Direct Aperture Optimization in Breast, Head and Neck IMRT Treatment

Inverse‐optimized 3D conformal planning: Minimizing complexity while achieving equivalence with beamlet IMRT in multiple clinical sites

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