Recommendations for implementing stereotactic radiotherapy in peripheral stage IA non-small cell lung cancer: report from the Quality Assurance Working Party of the randomised phase III ROSEL study

Hurkmans, Coen; Cuijpers, J.P.; Lagerwaard, Frank J.; Widder, Joachim; Heide, Uulke A. van der; Schuring, D.; Senan, Suresh

doi:10.1186/1748-717x-4-1

Cited by 222 publications

(180 citation statements)

References 55 publications

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“…As a conclusion, it is difficult to find an explicit relation for the location of a PTV. The similar behavior of the parameters can also be seen in a comprehensive comparison for the type ‘a’ and type ‘b’ algorithms by Hurkmans et al (8) The results in this study represent mostly the worst case scenario of the discrepancies between the algorithms concerning small targets locating centrally in the lung.…”

Section: Discussionsupporting

confidence: 81%

“…Five to seven or more conformal static treatment fields or arc techniques, such as volumetric‐modulated arc therapy (VMAT), enable rapid dose falloff away from target, which spares the normal tissue around the PTV. The history, development, and application of SBRT has been thoroughly presented in several review articles, 2 , 3 clinical trial and protocol reports, 4 , 5 , 6 , 7 , 8 and other comprehensive papers (9) by numerous research groups.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, this study demonstrates the performance of the new type ‘c’ algorithm for lung SBRT dose calculation with clinical plans. Requests for this kind of study can be found in the literature 8 , 11 . At the authors' clinic, the value of the work is self‐evident because, after the commissioning of lung SBRT for clinical use in 1999, for 75% of over 150 patients treated to date, the treatment plans have been calculated with the PBC algorithm (type ‘a’) and the rest with the AAA (type ‘b’).…”

Section: Introductionmentioning

confidence: 99%

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Performance of dose calculation algorithms from three generations in lung SBRT: comparison with full Monte Carlo‐based dose distributions

Ojala

Kapanen

Hyödynmaa

et al. 2014

J Applied Clin Med Phys

108

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The accuracy of dose calculation is a key challenge in stereotactic body radiotherapy (SBRT) of the lung. We have benchmarked three photon beam dose calculation algorithms — pencil beam convolution (PBC), anisotropic analytical algorithm (AAA), and Acuros XB (AXB) — implemented in a commercial treatment planning system (TPS), Varian Eclipse. Dose distributions from full Monte Carlo (MC) simulations were regarded as a reference. In the first stage, for four patients with central lung tumors, treatment plans using 3D conformal radiotherapy (CRT) technique applying 6 MV photon beams were made using the AXB algorithm, with planning criteria according to the Nordic SBRT study group. The plans were recalculated (with same number of monitor units (MUs) and identical field settings) using BEAMnrc and DOSXYZnrc MC codes. The MC‐calculated dose distributions were compared to corresponding AXB‐calculated dose distributions to assess the accuracy of the AXB algorithm, to which then other TPS algorithms were compared. In the second stage, treatment plans were made for ten patients with 3D CRT technique using both the PBC algorithm and the AAA. The plans were recalculated (with same number of MUs and identical field settings) with the AXB algorithm, then compared to original plans. Throughout the study, the comparisons were made as a function of the size of the planning target volume (PTV), using various dose‐volume histogram (DVH) and other parameters to quantitatively assess the plan quality. In the first stage also, 3D gamma analyses with threshold criteria 3normal%/3 mm and 2normal%/2 mm were applied. The AXB‐calculated dose distributions showed relatively high level of agreement in the light of 3D gamma analysis and DVH comparison against the full MC simulation, especially with large PTVs, but, with smaller PTVs, larger discrepancies were found. Gamma agreement index (GAI) values between 95.5% and 99.6% for all the plans with the threshold criteria 3normal%/3 mm were achieved, but 2normal%/2 mm threshold criteria showed larger discrepancies. The TPS algorithm comparison results showed large dose discrepancies in the PTV mean dose false(normalD50normal%false), nearly 60%, for the PBC algorithm, and differences of nearly 20% for the AAA, occurring also in the small PTV size range. This work suggests the application of independent plan verification, when the AAA or the AXB algorithm are utilized in lung SBRT having PTVs smaller than 20‐25 cc. The calculated data from this study can be used in converting the SBRT protocols based on type ‘a’ and/or type ‘b’ algorithms for the most recent generation type ‘c’ algorithms, such as the AXB algorithm.PACS numbers: 87.55.‐x, 87.55.D‐, 87.55.K‐, 87.55.kd, 87.55.Qr

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Section: Discussionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Performance of dose calculation algorithms from three generations in lung SBRT: comparison with full Monte Carlo‐based dose distributions

Ojala

Kapanen

Hyödynmaa

et al. 2014

J Applied Clin Med Phys

108

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“…where in 89.5% of cases a 7 field, all coplanar technique had 2 or less minor deviations 16. They too accounted for heterogeneity correction, but used the less stringent intermediate dose constraints from the ROSEL trial 18. The difference in intermediate dose constraints between RTOG 1021 and ROSEL significantly alters which beam arrangements are deemed acceptable.…”

Section: Discussionmentioning

confidence: 99%

“…report that in 17 of 19 cases, seven equidistant coplanar fields produced no more than two minor deviations. This group, however, used high‐ and intermediate dose constraints from the ROSEL study,18 which are more relaxed than those of RTOG. Furthermore, both Lim et al 15.…”

Section: Introductionmentioning

confidence: 99%

The effect of beam arrangements and the impact of non‐coplanar beams on the treatment planning of stereotactic ablative radiation therapy for early stage lung cancer

Fitzgerald

Owen

Barry

et al. 2015

J of Medical Radiation Sci

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IntroductionThe aim of this study was to compare various coplanar and non‐coplanar 3‐dimensional conformal radiation therapy (3DCRT) beam arrangements for the delivery of stereotactic ablative radiation therapy (SABR) to patients with early stage lung cancer, based on the dosimetric criteria from the Radiation Therapy Oncology Group (RTOG) 1021 protocol.MethodsTen medically inoperable lung cancer patients eligible for SABR were re‐planned using three different coplanar and three different non‐coplanar beam arrangements. The plans were compared by assessing planning target volume (PTV) coverage, doses to normal tissues, the high‐dose conformity (conformity index) and intermediate dose spillage as defined by the D2cm, (the dose at any point 2 cm away from the PTV), and the R50% (the ratio of the volume of half the prescription dose to the volume of the PTV).ResultsSixty plans in total were assessed. Mean PTV coverage with the prescription isodose was similar between coplanar (95.14%) and non‐coplanar (95.26%) techniques (P = 0.47). There was significant difference between all coplanar and all non‐coplanar fields for the R50% (P < 0.0001) but none for the D2cm (P = 0.19). The seven and nine field beam arrangements with two non‐coplanar fields had less unacceptable protocol deviations (10 and 7) than the seven and nine field plans with only coplanar fields (13 and 8). The 13 field coplanar fields did not improve protocol compliance with eight unacceptable deviations. The 10 field non‐coplanar beam arrangement achieved best compliance with the RTOG 1021 dose criteria with only one unacceptable deviation (maximum rib dose).ConclusionA 3DCRT planning technique using 10 fields with ≥6 non‐coplanar beams best satisfied high and intermediate dose constraints stipulated in the RTOG 1021 trial. Further investigations are required to determine if minor protocol deviations should be balanced against efficiency with the extended treatment times required to deliver non‐coplanar fields and if treatment times can be improved using novel intensity modulated techniques.

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Dose prescription with spatial uncertainty for peripheral lung SBRT

Bedford

Blasiak-Wal

Hansen³

2018

J Applied Clin Med Phys

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Current clinical practice is to prescribe to 95% of the planning target volume (PTV) in 4D stereotactic body radiotherapy (SBRT) for lung. Frequently the PTV margin has a very low physical density so that the internal target volume (ITV) receives an unnecessarily high dose. This study investigates the alternative of prescribing to the ITV while including the effects of positional uncertainties. Five patients were retrospectively studied with volumetric modulated arc therapy treatment plans. Five plans were produced for each patient: a static plan prescribed to PTV D 95%, three probabilistic plans prescribed to ITV D 95% and a static plan re‐prescribed to ITV D 95% after inverse planning. For the three probabilistic plans, the scatter kernel in the dose calculation was convolved with a spatial uncertainty distribution consisting of either a uniform distribution extending ±5 mm in the three orthogonal directions, a distribution consisting of delta functions at ±5 mm, or a Gaussian distribution with standard deviation 5 mm. Median ITV D 50% is 23% higher than the prescribed dose for static planning and only 10% higher than the prescribed dose for prescription to the ITV. The choice of uncertainty distribution has less than 2% effect on the median ITV dose. Re‐prescribing a static plan and evaluating with a probabilistic dose calculation results in a median ITV D 95% which is 1.5% higher than when planning probabilistically. This study shows that a robust probabilistic approach to planning SBRT lung treatments results in the ITV receiving a dose closer to the intended prescription. The exact form of the uncertainty distribution is not found to be critical.

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Recommendations for implementing stereotactic radiotherapy in peripheral stage IA non-small cell lung cancer: report from the Quality Assurance Working Party of the randomised phase III ROSEL study

Cited by 222 publications

References 55 publications

Performance of dose calculation algorithms from three generations in lung SBRT: comparison with full Monte Carlo‐based dose distributions

Performance of dose calculation algorithms from three generations in lung SBRT: comparison with full Monte Carlo‐based dose distributions

The effect of beam arrangements and the impact of non‐coplanar beams on the treatment planning of stereotactic ablative radiation therapy for early stage lung cancer

Dose prescription with spatial uncertainty for peripheral lung SBRT

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