Accuracy of out-of-field dose calculation of tomotherapy and cyberknife treatment planning systems: A dosimetric study

Schneider, Uwe; Hälg, Roger A.; Hartmann, Matthias; Mack, Andreas; Storelli, Fabrizio; Joosten, A.; Möckli, Raphaël; Besserer, Jürgen

doi:10.1016/j.zemedi.2013.10.008

Cited by 30 publications

(27 citation statements)

References 9 publications

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“…Importantly, the degree to which commercial treatment planning systems underestimate out-of-field dose varies strongly with position and the TPS dose algorithm used. These findings are similar to that which have recently been reported for a number of different TPSs and treatment modalities (Howell et al , 2010; Joosten et al , 2013b; Schneider et al , 2013). The analytical model proposed in this work, on the other hand, continues to predict measured doses at greater accuracy out to a distance of 40 cm from the CAX.…”

Section: Resultssupporting

confidence: 91%

“…To our knowledge, no contemporary commercial treatment planning system (TPS) includes the capability to accurately predict stray dose far from the treatment field. Thus, there is a large and systematic underestimation of stray radiation exposures by commonly used clinical TPSs (Howell et al , 2010; Schneider et al , 2014; Joosten et al , 2013a) and as a result, these doses and their effects are not accurately considered during treatment.…”

Section: Introductionmentioning

confidence: 99%

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A simple and fast physics-based analytical method to calculate therapeutic and stray doses from external beam, megavoltage x-ray therapy

Jagetic

Newhauser

2015

Phys. Med. Biol.

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State-of-the-art radiotherapy treatment planning systems provide reliable estimates of the therapeutic radiation but are known to underestimate or neglect the stray radiation exposures. Most commonly, stray radiation exposures are reconstructed using empirical formulas or lookup tables. The purpose of this study was to develop the basic physics of a model capable of calculating the total absorbed dose both inside and outside of the therapeutic radiation beam for external beam photon therapy. The model was developed using measurements of total absorbed dose in a water-box phantom from a 6 MV medical linear accelerator to calculate dose profiles in both the in-plane and cross-plane direction for a variety of square field sizes and depths in water. The water-box phantom facilitated development of the basic physical aspects of the model. RMS discrepancies between measured and calculated total absorbed dose values in water were less than 9.3% for all fields studied. Computation times for 10 million dose points within a homogeneous phantom were approximately 4 minutes. These results suggest that the basic physics of the model are sufficiently simple, fast, and accurate to serve as a foundation for a variety of clinical and research applications, some of which may require that the model be extended or simplified based on the needs of the user. A potentially important advantage of a physics-based approach is that the model is more readily adaptable to a wide variety of treatment units and treatment techniques than with empirical models.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

A simple and fast physics-based analytical method to calculate therapeutic and stray doses from external beam, megavoltage x-ray therapy

Jagetic

Newhauser

2015

Phys. Med. Biol.

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“…Out-of-field dosimetry requires a direct measurement as commercial treatment planning systems cannot estimate dose outside the radiation field well [13, 14]. We used RPLGD dosimeters (A.T.G., Chiyoda Technology Corporation, Tokyo, Japan) to estimate the out-of-field organ doses.…”

Section: Methodsmentioning

confidence: 99%

Estimation of the risk of secondary malignancy arising from whole-breast irradiation: comparison of five radiotherapy modalities, including TomoHDA

Han

Paudel

Sung³

et al. 2016

Oncotarget

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The risk of secondary cancer from radiation treatment remains a concern for long-term breast cancer survivors, especially those treated with radiation at the age younger than 45 years. Treatment modalities optimally maximize the dose delivery to the tumor while minimizing radiation doses to neighboring organs, which can lead to secondary cancers. A new TomoTherapy treatment machine, TomoHDATM, can treat an entire breast with two static but intensity-modulated beams in a slice-by-slice fashion. This feature could reduce scattered and leakage radiation doses. We compared the plan quality and lifetime attributable risk (LAR) of a second malignancy among five treatment modalities: three-dimensional conformal radiation therapy, field-in-field forward-planned intensity-modulated radiation therapy, inverse-planned intensity-modulated radiation therapy (IMRT), volumetric modulated arc therapy, and TomoDirect mode on the TomoHDA system. Ten breast cancer patients were selected for retrospective analysis. Organ equivalent doses, plan characteristics, and LARs were compared. Out-of-field organ doses were measured with radio-photoluminescence glass dosimeters. Although the IMRT plan provided overall better plan quality, including the lowest probability of pneumonitis, it caused the second highest LAR. The TomoTherapy plan provided plan quality comparable to the IMRT plan and posed the lowest total LAR to neighboring organs. Therefore, it can be a better treatment modality for younger patients who have a longer life expectancy.

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“…r ( x m , x c ) is the difference in position between measured and calculated dose values, Δ d T and Δ d OOF are the distance to agreement criteria in the therapeutic and out‐of‐field regions, respectively, δ R ( x m , x c ) represents the relative dose difference between measured and calculated dose values, Δ D R is the relative dose difference criterion, δ A ( x m , x c ) represents the absolute dose difference between measured and calculated dose values, and Δ D A is the absolute dose difference criterion. The therapeutic dose region was delineated from the out‐of‐field dose region at the 1% relative dose level based on previously published findings . This allows for a significantly more severe dosimetric test out‐of‐field than conventional methods.…”

Section: Methodsmentioning

confidence: 99%

A descriptive and broadly applicable model of therapeutic and stray absorbed dose from 6 to 25 MV photon beams

et al. 2017

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Accuracy of out-of-field dose calculation of tomotherapy and cyberknife treatment planning systems: A dosimetric study

Cited by 30 publications

References 9 publications

A simple and fast physics-based analytical method to calculate therapeutic and stray doses from external beam, megavoltage x-ray therapy

A simple and fast physics-based analytical method to calculate therapeutic and stray doses from external beam, megavoltage x-ray therapy

Estimation of the risk of secondary malignancy arising from whole-breast irradiation: comparison of five radiotherapy modalities, including TomoHDA

A descriptive and broadly applicable model of therapeutic and stray absorbed dose from 6 to 25 MV photon beams

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