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  1. Article ; Online: A head and neck treatment planning strategy for a CBCT-guided ring-gantry online adaptive radiotherapy system.

    Nasser, Nour / Yang, George Q / Koo, Jihye / Bowers, Mark / Greco, Kevin / Feygelman, Vladimir / Moros, Eduardo G / Caudell, Jimmy J / Redler, Gage

    Journal of applied clinical medical physics

    2023  Volume 24, Issue 12, Page(s) e14134

    Abstract: Purpose: A planning strategy was developed and the utility of online-adaptation with the Ethos CBCT-guided ring-gantry adaptive radiotherapy (ART) system was evaluated using retrospective data from Head-and-neck (H&N) patients that required clinical ... ...

    Abstract Purpose: A planning strategy was developed and the utility of online-adaptation with the Ethos CBCT-guided ring-gantry adaptive radiotherapy (ART) system was evaluated using retrospective data from Head-and-neck (H&N) patients that required clinical offline adaptation during treatment.
    Methods: Clinical data were used to re-plan 20 H&N patients (10 sequential boost (SEQ) with separate base and boost plans plus 10 simultaneous integrated boost (SIB)). An optimal approach, robust to online adaptation, for Ethos-initial plans using clinical goal prioritization was developed. Anatomically-derived isodose-shaping helper structures, air-density override, goals for controlling hotspot location(s), and plan normalization were investigated. Online adaptation was simulated using clinical offline adaptive simulation-CTs to represent an on-treatment CBCT. Dosimetric comparisons were based on institutional guidelines for Clinical-initial versus Ethos-initial plans and Ethos-scheduled versus Ethos-adapted plans. Timing for five components of the online adaptive workflow was analyzed.
    Results: The Ethos H&N planning approach generated Ethos-initial SEQ plans with clinically comparable PTV coverage (average PTV
    Conclusions: With an optimal planning approach, Ethos efficiently auto-generated dosimetrically comparable and clinically acceptable initial SEQ plans for H&N patients. Initial SIB plans were inferior and clinically unacceptable, but adapted SIB plans became clinically acceptable. Online adapted plans optimized dose to new anatomy and maintained target coverage/homogeneity with improved OAR sparing in a time-efficient manner.
    MeSH term(s) Humans ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; Retrospective Studies ; Spiral Cone-Beam Computed Tomography ; Organs at Risk ; Radiotherapy, Intensity-Modulated
    Language English
    Publishing date 2023-08-24
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2010347-5
    ISSN 1526-9914 ; 1526-9914
    ISSN (online) 1526-9914
    ISSN 1526-9914
    DOI 10.1002/acm2.14134
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Maintaining dosimetric quality when switching to a Monte Carlo dose engine for head and neck volumetric-modulated arc therapy planning.

    Feygelman, Vladimir / Latifi, Kujtim / Bowers, Mark / Greco, Kevin / Moros, Eduardo G / Isacson, Max / Angerud, Agnes / Caudell, Jimmy

    Journal of applied clinical medical physics

    2022  Volume 23, Issue 5, Page(s) e13572

    Abstract: Head and neck cancers present challenges in radiation treatment planning due to the large number of critical structures near the target(s) and highly heterogeneous tissue composition. While Monte Carlo (MC) dose calculations currently offer the most ... ...

    Abstract Head and neck cancers present challenges in radiation treatment planning due to the large number of critical structures near the target(s) and highly heterogeneous tissue composition. While Monte Carlo (MC) dose calculations currently offer the most accurate approximation of dose deposition in tissue, the switch to MC presents challenges in preserving the parameters of care. The differences in dose-to-tissue were widely discussed in the literature, but mostly in the context of recalculating the existing plans rather than reoptimizing with the MC dose engine. Also, the target dose homogeneity received less attention. We adhere to strict dose homogeneity objectives in clinical practice. In this study, we started with 21 clinical volumetric-modulated arc therapy (VMAT) plans previously developed in Pinnacle treatment planning system. Those plans were recalculated "as is" with RayStation (RS) MC algorithm and then reoptimized in RS with both collapsed cone (CC) and MC algorithms. MC statistical uncertainty (0.3%) was selected carefully to balance the dose computation time (1-2 min) with the planning target volume (PTV) dose-volume histogram (DVH) shape approaching that of a "noise-free" calculation. When the hot spot in head and neck MC-based treatment planning is defined as dose to 0.03 cc, it is exceedingly difficult to limit it to 105% of the prescription dose, as we were used to with the CC algorithm. The average hot spot after optimization and calculation with RS MC was statistically significantly higher compared to Pinnacle and RS CC algorithms by 1.2 and 1.0 %, respectively. The 95% confidence interval (CI) observed in this study suggests that in most cases a hot spot of ≤107% is achievable. Compared to the 95% CI for the previous clinical plans recalculated with RS MC "as is" (upper limit 108%), in real terms this result is at least as good or better than the historic plans.
    MeSH term(s) Algorithms ; Humans ; Monte Carlo Method ; Radiometry ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; Radiotherapy, Intensity-Modulated
    Language English
    Publishing date 2022-02-25
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2010347-5
    ISSN 1526-9914 ; 1526-9914
    ISSN (online) 1526-9914
    ISSN 1526-9914
    DOI 10.1002/acm2.13572
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  3. Article ; Online: Radiobiological and dosimetric impact of RayStation pencil beam and Monte Carlo algorithms on intensity-modulated proton therapy breast cancer plans.

    Rana, Suresh / Greco, Kevin / Samuel, E James Jebaseelan / Bennouna, Jaafar

    Journal of applied clinical medical physics

    2019  Volume 20, Issue 8, Page(s) 36–46

    Abstract: Purpose: RayStation treatment planning system employs pencil beam (PB) and Monte Carlo (MC) algorithms for proton dose calculations. The purpose of this study is to evaluate the radiobiological and dosimetric impact of RayStation PB and MC algorithms on ...

    Abstract Purpose: RayStation treatment planning system employs pencil beam (PB) and Monte Carlo (MC) algorithms for proton dose calculations. The purpose of this study is to evaluate the radiobiological and dosimetric impact of RayStation PB and MC algorithms on the intensity-modulated proton therapy (IMPT) breast plans.
    Methods: The current study included ten breast cancer patients, and each patient was treated with 1-2 proton beams to the whole breast/chestwall (CW) and regional lymph nodes in 28 fractions for a total dose of 50.4 Gy relative biological effectiveness (RBE). A total clinical target volume (CTV_Total) was generated by combining individual CTVs: AxI, AxII, AxIII, CW, IMN, and SCVN. All beams in the study were treated with a range shifter (7.5 cm water equivalent thickness). For each patient, three sets of plans were generated: (a) PB optimization followed by PB dose calculation (PB-PB), (b) PB optimization followed by MC dose calculation (PB-MC), and (c) MC optimization followed by MC dose calculation (MC-MC). For a given patient, each plan was robustly optimized on the CTVs with same parameters and objectives. Treatment plans were evaluated using dosimetric and radiobiological indices (equivalent uniform dose (EUD), tumor control probability (TCP), and normal tissue complication probability (NTCP)).
    Results: The results are averaged over ten breast cancer patients. In comparison to PB-PB plans, PB-MC plans showed a reduction in CTV target dose by 5.3% for D
    Conclusion: If MC is more accurate than PB as reported in the literature, dosimetric and radiobiological results from the current study suggest that PB overestimates the target dose, EUD, and TCP for IMPT breast cancer treatment. The overestimation of dosimetric and radiobiological results of the target volume by PB needs to be further interpreted in terms of clinical outcome.
    MeSH term(s) Algorithms ; Breast Neoplasms/radiotherapy ; Female ; Humans ; Monte Carlo Method ; Organs at Risk/radiation effects ; Prognosis ; Proton Therapy/methods ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted/methods ; Radiotherapy, Intensity-Modulated/methods
    Language English
    Publishing date 2019-07-25
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2010347-5
    ISSN 1526-9914 ; 1526-9914
    ISSN (online) 1526-9914
    ISSN 1526-9914
    DOI 10.1002/acm2.12676
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

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