Helical tomotherapy for SIB and hypo-fractionated treatments in lung carcinomas: A 4D Monte Carlo treatment planning study

Sterpin, Edmond; Janssens, Guillaume; Xivry, Jonathan Orban de; Goossens, Samuel; Wanet, Marie; Lee, John A.; Delor, Antoine; Bol, Vanesa; Vynckier, Stefaan; Grégoire, Vincent; Geets, Xavier

doi:10.1016/j.radonc.2012.06.005

Cited by 26 publications

(26 citation statements)

References 43 publications

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“…different from 5 s) during the whole treatment, by selecting an appropriate but still comfortable breathing period. Fortunately, such aliasing is not relevant for the helical treatment delivery, the latter being rather insensitive to beam and tumor motion interplay effects [29][30][31]. Secondly, the influence of surrounding tissues or bones in the registration procedure may result in erroneous tumor positioning.…”

Section: Discussionmentioning

confidence: 99%

Impact of motion induced artifacts on automatic registration of lung tumors in Tomotherapy

et al. 2015

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Section: Discussionmentioning

confidence: 99%

Impact of motion induced artifacts on automatic registration of lung tumors in Tomotherapy

et al. 2015

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“…Wedged techniques or field-in-field techniques seem insensitive for breathing motion, while IMRT techniques are highly sensitive to movement [21]. Tomotherapy uses IMRT, but plan delivery accuracy doesn't seem significantly affected by breathing [22]. …”

Section: Discussionmentioning

confidence: 99%

Breast conserving treatment for breast cancer: dosimetric comparison of different non-invasive techniques for additional boost delivery

et al. 2014

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BackgroundToday it is unclear which technique for delivery of an additional boost after whole breast radiotherapy for breast conserved patients should be state of the art. We present a dosimetric comparison of different non-invasive treatment techniques for additional boost delivery.MethodsFor 10 different tumor bed localizations, 7 different non-invasive treatment plans were made. Dosimetric comparison of PTV-coverage and dose to organs at risk was performed.ResultsThe Vero system achieved an excellent PTV-coverage and at the same time could minimize the dose to the organs at risk with an average near-maximum-dose (D2) to the heart of 0.9 Gy and the average volume of ipsilateral lung receiving 5 Gy (V5) of 1.5%. The TomoTherapy modalities delivered an average D2 to the heart of 0.9 Gy for the rotational and of 2.3 Gy for the static modality and an average V5 to the ipsilateral lung of 7.3% and 2.9% respectively. A rotational technique offers an adequate conformity at the cost of more low dose spread and a larger build-up area. In most cases a 2-field technique showed acceptable PTV-coverage, but a bad conformity. Electrons often delivered a worse PTV-coverage than photons, with the planning requirements achieved only in 2 patients and with an average D2 to the heart of 2.8 Gy and an average V5 to the ipsilateral lung of 5.8%.ConclusionsWe present advices which can be used as guidelines for the selection of the best individualized treatment.

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“…The interplay effect has been extensively studied for various photon radiotherapy techniques such as IMRT (Pedroni et al 2005; Bortfeld et al 2002; Berbeco et al 2006), Tomotherapy (Phillips et al 1992; Sterpin et al 2012; Seco et al 2009), RapidArc (Ong et al 2011) and VMAT (Rao et al 2012). The general consensus from these previous studies is that the interplay effect is insignificant for fractionated photon techniques, as any variations induced average out over the course of a conventionally fractionated treatment.…”

Section: Introductionmentioning

confidence: 99%

Interplay effects in proton scanning for lung: a 4D Monte Carlo study assessing the impact of tumor and beam delivery parameters

et al. 2013

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Relative motion between a tumor and a scanning proton beam results in a degradation of the dose distribution (interplay effect). This study investigates the relationship between beam scanning parameters and the interplay effect, with the goal of finding parameters that minimize interplay. 4D Monte Carlo simulations of pencil beam scanning proton therapy treatments were performed using the 4DCT geometry of 5 lung cancer patients of varying tumor size (50.4–167.1cc) and motion amplitude (2.9–30.1mm). Treatments were planned assuming delivery in 35×2.5Gy(RBE) fractions. The spot size, time to change the beam energy (τes), time required for magnet settling (τss), initial breathing phase, spot spacing, scanning direction, scanning speed, beam current and patient breathing period were varied for each of the 5 patients. Simulations were performed for a single fraction and an approximation of conventional fractionation. For the patients considered, the interplay effect could not be predicted using the superior-inferior (SI) motion amplitude alone. Larger spot sizes (σ ~9–16mm) were less susceptible to interplay, giving an equivalent uniform dose (EUD) of 99.0±4.4% (1 standard deviation) in a single fraction compared to 86.1±13.1% for smaller spots (σ ~2–4mm). The smaller spot sizes gave EUD values as low as 65.3% of the prescription dose in a single fraction. Reducing the spot spacing improved the target dose homogeneity. The initial breathing phase can have a significant effect on the interplay, particularly for shorter delivery times. No clear benefit was evident when scanning either parallel or perpendicular to the predominant axis of motion. Longer breathing periods decreased the EUD. In general, longer delivery times led to lower interplay effects. Conventional fractionation showed significant improvement in terms of interplay, giving a EUD of at least 84.7% and 100.0% of the prescription dose for the small and larger spot sizes respectively. The interplay effect is highly patient specific, depending on the motion amplitude, tumor location and the delivery parameters. Large degradations of the dose distribution in a single fraction were observed, but improved significantly using conventional fractionation.

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Helical tomotherapy for SIB and hypo-fractionated treatments in lung carcinomas: A 4D Monte Carlo treatment planning study

Cited by 26 publications

References 43 publications

Impact of motion induced artifacts on automatic registration of lung tumors in Tomotherapy

Impact of motion induced artifacts on automatic registration of lung tumors in Tomotherapy

Breast conserving treatment for breast cancer: dosimetric comparison of different non-invasive techniques for additional boost delivery

Interplay effects in proton scanning for lung: a 4D Monte Carlo study assessing the impact of tumor and beam delivery parameters

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