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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.


ICRU dose report parameters for one exemplary case (case 1) for all 5 participating institutions. The connecting lines should enhance the distinction between institutions
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Fig3: ICRU dose report parameters for one exemplary case (case 1) for all 5 participating institutions. The connecting lines should enhance the distinction between institutions

Mentions: In Fig. 3 the ICRU dose report parameters are shown for one example case (case 1) for all 5 participating institutions. Good agreement is demonstrated for the parameters D90 and Dmean with a maximum deviation of 2.4 Gy and 1.1 Gy. A higher variability is demonstrated for the other dose report parameters – especially for D98, D95 and Dmax with a maximum difference of 4.9 Gy, 5.1 Gy and 4.6 Gy for this example case. Over all cases, the maximum deviation in D98 and D95 was 8.5 Gy and 7.6 GyFig. 3


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)

ICRU dose report parameters for one exemplary case (case 1) for all 5 participating institutions. The connecting lines should enhance the distinction between institutions
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig3: ICRU dose report parameters for one exemplary case (case 1) for all 5 participating institutions. The connecting lines should enhance the distinction between institutions
Mentions: In Fig. 3 the ICRU dose report parameters are shown for one example case (case 1) for all 5 participating institutions. Good agreement is demonstrated for the parameters D90 and Dmean with a maximum deviation of 2.4 Gy and 1.1 Gy. A higher variability is demonstrated for the other dose report parameters – especially for D98, D95 and Dmax with a maximum difference of 4.9 Gy, 5.1 Gy and 4.6 Gy for this example case. Over all cases, the maximum deviation in D98 and D95 was 8.5 Gy and 7.6 GyFig. 3

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.