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Variability in spine radiosurgery treatment planning - results of an international multi-institutional study.

Toussaint A, Richter A, Mantel F, Flickinger JC, Grills IS, Tyagi N, Sahgal A, Letourneau D, Sheehan JP, Schlesinger DJ, Gerszten PC, Guckenberger M - Radiat Oncol (2016)

Bottom Line: In addition, each institution generated one additional SRS plan for each case based on intra-institutional image registration and contouring, independent of consensus results.Despite close methodical agreement in the daily workflow, clinically significant variability in all steps of the treatment planning process was demonstrated.This may translate into differences in patient clinical outcome and highlights the need for consensus and established delineation and planning criteria.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany. toussaint_a@ukw.de.

ABSTRACT

Background: The aim of this study was to quantify the variability in spinal radiosurgery (SRS) planning practices between five international institutions, all member of the Elekta Spine Radiosurgery Research Consortium.

Methods: Four institutions provided one representative patient case each consisting of the medical history, CT and MR imaging. A step-wise planning approach was used where, after each planning step a consensus was generated that formed the basis for the next planning step. This allowed independent analysis of all planning steps of CT-MR image registration, GTV definition, CTV definition, PTV definition and SRS treatment planning. In addition, each institution generated one additional SRS plan for each case based on intra-institutional image registration and contouring, independent of consensus results.

Results: Averaged over the four cases, image registration variability ranged between translational 1.1 mm and 2.4 mm and rotational 1.1° and 2.0° in all three directions. GTV delineation variability was 1.5 mm in axial and 1.6 mm in longitudinal direction averaged for the four cases. CTV delineation variability was 0.8 mm in axial and 1.2 mm in longitudinal direction. CTV-to-PTV margins ranged between 0 mm and 2 mm according to institutional protocol. Delineation variability was 1 mm in axial directions for the spinal cord. Average PTV coverage for a single fraction18 Gy prescription was 87 ± 5 %; Dmin to the PTV was 7.5 ± 1.8 Gy averaged over all cases and institutions. Average Dmax to the PRV_SC (spinal cord + 1 mm) was 10.5 ± 1.6 Gy and the average Paddick conformity index was 0.69 ± 0.06.

Conclusions: Results of this study reflect the variability in current practice of spine radiosurgery in large and highly experienced academic centers. Despite close methodical agreement in the daily workflow, clinically significant variability in all steps of the treatment planning process was demonstrated. This may translate into differences in patient clinical outcome and highlights the need for consensus and established delineation and planning criteria.

No MeSH data available.


Performance parameters RTOG coverage for all analyzed plans. Abbreviation: results of case 1–4 with consensus (c) and individual (i) plans
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Fig5: Performance parameters RTOG coverage for all analyzed plans. Abbreviation: results of case 1–4 with consensus (c) and individual (i) plans

Mentions: For the PTVindividual based planning process, the variations on planning performance was higher compared to the consensus based planning. Performance parameters are illustrated in Figs. 5 and 6. All discrete values are illustrated with blue dots. Mean values over all institutions are shown in blue squares with standard deviation as error bars. In Fig. 5, the minor deviation range according to the respective protocol is shaded in light blue while major deviation rang is shown in shaded deeper blue.Fig. 5


Variability in spine radiosurgery treatment planning - results of an international multi-institutional study.

Toussaint A, Richter A, Mantel F, Flickinger JC, Grills IS, Tyagi N, Sahgal A, Letourneau D, Sheehan JP, Schlesinger DJ, Gerszten PC, Guckenberger M - Radiat Oncol (2016)

Performance parameters RTOG coverage for all analyzed plans. Abbreviation: results of case 1–4 with consensus (c) and individual (i) plans
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4835862&req=5

Fig5: Performance parameters RTOG coverage for all analyzed plans. Abbreviation: results of case 1–4 with consensus (c) and individual (i) plans
Mentions: For the PTVindividual based planning process, the variations on planning performance was higher compared to the consensus based planning. Performance parameters are illustrated in Figs. 5 and 6. All discrete values are illustrated with blue dots. Mean values over all institutions are shown in blue squares with standard deviation as error bars. In Fig. 5, the minor deviation range according to the respective protocol is shaded in light blue while major deviation rang is shown in shaded deeper blue.Fig. 5

Bottom Line: In addition, each institution generated one additional SRS plan for each case based on intra-institutional image registration and contouring, independent of consensus results.Despite close methodical agreement in the daily workflow, clinically significant variability in all steps of the treatment planning process was demonstrated.This may translate into differences in patient clinical outcome and highlights the need for consensus and established delineation and planning criteria.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany. toussaint_a@ukw.de.

ABSTRACT

Background: The aim of this study was to quantify the variability in spinal radiosurgery (SRS) planning practices between five international institutions, all member of the Elekta Spine Radiosurgery Research Consortium.

Methods: Four institutions provided one representative patient case each consisting of the medical history, CT and MR imaging. A step-wise planning approach was used where, after each planning step a consensus was generated that formed the basis for the next planning step. This allowed independent analysis of all planning steps of CT-MR image registration, GTV definition, CTV definition, PTV definition and SRS treatment planning. In addition, each institution generated one additional SRS plan for each case based on intra-institutional image registration and contouring, independent of consensus results.

Results: Averaged over the four cases, image registration variability ranged between translational 1.1 mm and 2.4 mm and rotational 1.1° and 2.0° in all three directions. GTV delineation variability was 1.5 mm in axial and 1.6 mm in longitudinal direction averaged for the four cases. CTV delineation variability was 0.8 mm in axial and 1.2 mm in longitudinal direction. CTV-to-PTV margins ranged between 0 mm and 2 mm according to institutional protocol. Delineation variability was 1 mm in axial directions for the spinal cord. Average PTV coverage for a single fraction18 Gy prescription was 87 ± 5 %; Dmin to the PTV was 7.5 ± 1.8 Gy averaged over all cases and institutions. Average Dmax to the PRV_SC (spinal cord + 1 mm) was 10.5 ± 1.6 Gy and the average Paddick conformity index was 0.69 ± 0.06.

Conclusions: Results of this study reflect the variability in current practice of spine radiosurgery in large and highly experienced academic centers. Despite close methodical agreement in the daily workflow, clinically significant variability in all steps of the treatment planning process was demonstrated. This may translate into differences in patient clinical outcome and highlights the need for consensus and established delineation and planning criteria.

No MeSH data available.