Evaluation of organ motion-based robust optimisation for VMAT planning for breast and internal mammary chain radiotherapy

Dunlop, A.; Colgan, R.; Kirby, Anna M.; Ranger, A.; Blasiak-Wal, I.

doi:10.1016/j.ctro.2019.04.004

Cited by 16 publications

(18 citation statements)

References 22 publications

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“…The main disadvantage of this method was that dose distribution of radiotherapy plan used for the nal evaluation was not optimized based on actual radiotherapy implementation status, so this plan was not guaranteed to be the actual optimal solution. Moreover, since VB removed away, the nal dose distribution was inadequate for protection of organs at risk compared with the initial optimized results 14 .…”

Section: Introductionmentioning

confidence: 98%

“…Fredriksson proposed that adding Robust optimization could signi cantly increase the patient's skin dose, and to some extent, it could replace the e cacy of VB22 . The Alex Dunlop team added Robust optimization to study breast cancer radiotherapy based on organ motion, found that D 98 , D 95 , D 50 and D 2 of CTV that added Robust optimization were signi cantly different from treatments without Robust optimization (P<0.01), they proposed that the use of robust optimization based on organ motion to generate VMAT plan is clinically acceptable for the typical and extreme target area changes during treatment14 . Hideharu Miura et al veri ed the advantages of introducing Robust in other tumor types with greater CTV activity, such as Larynx cancer,Robust-optimized plan had better CTV coverage rate than that without Robust-optimized, and less carotid artery exposure dose…”

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confidence: 99%

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WITHDRAWN: The Dosimetric Advantages of Robust Optimization Combined With Flatten Filter Free Mode in Left Breast Cancer

Luo¹,

Shan²,

Shao³

et al. 2020

Preprint

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Background and purposesTo explore the advantages of Robust optimization in dosimetry under flatten filter free(FFF) Mode after left breast cancer surgery.Materials and methods21 patients with left breast cancer after surgery were randomly selected from 2019 to 2020. The planned target volume (PTV) dose was prescribed 50Gy /25times and B. With or without Robust optimization were designed on the RayStation planning system with Volume rotary intensity-modulated radiotherapy technology based on the FFF Mode. By moving the center point of the field to simulated the movement of target area of the internal chest wall (0.50cm) caused by Respiratory movement, dosimetry characteristics. Using spss 23.0 to analyse the datum.Resultswhen the chest wall target moved outward, the PTV target area D98, D95, D2, CI and HI with Robust optimization were better than those without Robust, and the coverage rate of PTV-CHESTV50 was significantly higher than that without Robust optimization (P=0.000060), which was 15.39% higher than that without Robust optimization. CTVV50 coverage with Robust optimization was higher than that without Robust optimization, with an increase of 14.48%. In terms of endangering organ parameters, the average spinal cord dose of the plan with Robust optimization was 13.19% lower than that of the plan without Robust optimization, and the lung V5 of the plan without Robust optimization was slightly lower than that of the plan with Robust optimization, which was 1.80% lower than that of the plan without Robust optimization. There was no significant difference in machine execution efficiency between the two groups (P > 0.05).ConclusionsThe Robust optimization could be adopted in the development of postoperative left breast cancer radiotherapy plan, which ensures that the target dose coverage and the dose limit of organ-at-risk still meet the clinical requirements under condition of chest wall displacement caused by respiratory movement.

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Section: Introductionmentioning

confidence: 98%

mentioning

confidence: 99%

WITHDRAWN: The Dosimetric Advantages of Robust Optimization Combined With Flatten Filter Free Mode in Left Breast Cancer

Luo¹,

Shan²,

Shao³

et al. 2020

Preprint

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show abstract

“…Alternatively, future work may further develop sitespecific models of anatomical variation for breast treatments to handle these uncertainties via scenario-based robust optimization methods. For example, Dunlop et al [31] suggested a robust optimization approach for VMAT planning using a PTV margin and a number of simulated CTs representing anatomical changes of the breast with motions of the breast CTV. The primary goal of this work is to evaluate the benefit of combining an FBL and a LINAC in a treatment room for breast cancer patients.…”

Section: Discussionmentioning

confidence: 99%

Combined proton–photon treatment for breast cancer

et al. 2021

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Objective. Proton therapy remains a limited resource due to gantry size and its cost. Recently, a new design without a gantry has been suggested. It may enable combined proton–photon therapy (CPPT) in conventional bunkers and allow the widespread use of protons. In this work, we explore this concept for breast cancer. Methods. The treatment room consists of a LINAC for intensity modulated radiation therapy (IMRT), a fixed proton beamline (FBL) with beam scanning and a motorized couch for treatments in lying positions with accurate patient setup. Thereby, proton and photon beams are delivered in the same fraction. Treatment planning is performed by simultaneously optimizing IMRT and IMPT plans based on the cumulative dose. The concept is investigated for three breast cancers where the goal is to minimize mean dose to the heart and lung while delivering 40.05 Gy in 15 fractions to the PTV with a SIB of 48 Gy to the tumor bed. The probabilistic approach is applied to mitigate the sensitivity to range uncertainties. Results. CPPT is particularly advantageous for irradiating concave target volumes that wrap around a curved chest wall. There, protons may deliver dose to the peripheral and medial parts of the target volume including lymph nodes. Thereby, the mean dose in normal tissues is reduced compared to single-modality IMRT. However, tangential photon beams may treat parts of the target volume near the interface to the lung. To ensure target coverage for range undershoot in an IMPT plan, proton beams have to deliberately overshoot into the lung tissue—a problem that can be mitigated via the photon component which ensures plan conformity and robustness. Conclusion. CPPT using an FBL may represent a realistic approach to make protons available to more patients. In addition, CPPT may generally improve treatment quality compared to both single-modality proton and photon treatments.

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“…Strong robustness was needed in precision radiotherapy, especially like dose painting which put forward non-uniform prescribed dose in CTV to escalate the dose to regions of high risk and meanwhile de-escalate the dose of the low-risk region. Recently, The robustness optimization methods had been developed by incorporating uncertainty in plan optimization, for CTV should receive the prescribed dose depended on desired dose distribution and dose fall-off near the target rather than geometric margin [29]. Lowe, M. et al [30] believed robustness optimization was an effective method to reduce dose to normal tissues that would be unnecessarily irradiated with the PTV-margin concept.…”

Section: Discussionmentioning

confidence: 99%

A Plan Robustness Qualification Method of Volumetric Arc Radiotherapy (VMAT) of Set Up Uncertainty in Nasopharyngeal Carcinoma (NPC) Radiotherapy

Ding¹,

Xiang²,

Qi³

et al. 2021

Preprint

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Purpose: To evaluate the set-up sensitivity of VMAT plans for Nasopharyngeal carcinoma (NPC) treatment by proposing a plan robustness evaluation method. Methods: 10 patients were selected for this study. A 2-arc volumetric-modulated arc therapy (VMAT) plan was generated for each patient using Varian Eclipse (13.6 Version) treatment planning system (TPS). 5 uncertainty plans (U-plans) were calculated based on the first 5 times set-up errors acquired from cone beam comuter tomography (CBCT). The dose differences and plan robustness of all the PTVs, CTVs, GTVs, and organs at risk (OARs) were analyzed. Tumor control probability (TCP) and normal tissues complication probability (NTCP) were calculated for biological evaluation. Results: The mean dose differences of D98 and D95 (△D98 and△D95) of PTVnx were respectively 3.30 Gy and 2.02 Gy. The △D98 and△D95 of CTVnx were 1.12 Gy and 0.58 Gy. The △D98 and△D95 of GTVnx were 0.56 Gy and 0.33 Gy. The dose coverage of GTVnx and CTVnx was guaranteed with minor dose variation. GTVnd exhibited strong robustness with little variation of D98 (0.5%) and D95 (0.9%). The △D98 and△D95 of CTVnd were 1.39 Gy and 1.03 Gy, distinctively lower than those in PTVnd (2.8 Gy and 2.0 Gy). No marked mean dose variations of Dmean were seen. The mean reduction of TCP (△TCP) in GTVnx and CTVnx were respectively 0.4% and 0.3%. The mean △TCP of GTVnd and CTVnd were 0.92 % and 1.3 % respectively. The CTV exhibited the largest △TCP (2.2 %). In OARs, the optical nerve chiasma was the one with the highest change, with a mean dose variation of 8.81 Gy. The Dmean of bilateral parotids varied in a large range. The mean reduction of NTCP (△NTCP) in the left parotid gland was 13.30%, which sharply increased the risk of parotid gland dysfunction. Conclusion: VMAT plans had a strong sensitivity to set-up uncertainty in NPC radiotherapy, due to the high degree of modulation. We proposed an effective method to evaluate the plan robustness of VMAT plans. Plan robustness and complexity should be taken into account in photon radiotherapy.

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Evaluation of organ motion-based robust optimisation for VMAT planning for breast and internal mammary chain radiotherapy

Cited by 16 publications

References 22 publications

WITHDRAWN: The Dosimetric Advantages of Robust Optimization Combined With Flatten Filter Free Mode in Left Breast Cancer

WITHDRAWN: The Dosimetric Advantages of Robust Optimization Combined With Flatten Filter Free Mode in Left Breast Cancer

Combined proton–photon treatment for breast cancer

A Plan Robustness Qualification Method of Volumetric Arc Radiotherapy (VMAT) of Set Up Uncertainty in Nasopharyngeal Carcinoma (NPC) Radiotherapy

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