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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.


Related in: MedlinePlus

a/b Maximum planning risk volume spinal cord (PRV_SC) doses to PTV minimum doses and dose to 0,1ccm of spinal cord to PTV D98 for all cases and institutions
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Fig4: a/b Maximum planning risk volume spinal cord (PRV_SC) doses to PTV minimum doses and dose to 0,1ccm of spinal cord to PTV D98 for all cases and institutions

Mentions: Figure 4a illustrates the maximum dose to the planning risk volume spinal cord (Dmax PRV_SC) as a function of the minimum dose in the PTV (Dmin PTV). Fig. 4b shows the dose to 0.1 cm3 of the spinal cord to the D98 in the PTV. A very strong correlation can be seen - especially between D0.1ccm(SC) and D98(PTV) with a coefficient of determination of R2 = 0.81.Fig. 4


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)

a/b Maximum planning risk volume spinal cord (PRV_SC) doses to PTV minimum doses and dose to 0,1ccm of spinal cord to PTV D98 for all cases and institutions
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig4: a/b Maximum planning risk volume spinal cord (PRV_SC) doses to PTV minimum doses and dose to 0,1ccm of spinal cord to PTV D98 for all cases and institutions
Mentions: Figure 4a illustrates the maximum dose to the planning risk volume spinal cord (Dmax PRV_SC) as a function of the minimum dose in the PTV (Dmin PTV). Fig. 4b shows the dose to 0.1 cm3 of the spinal cord to the D98 in the PTV. A very strong correlation can be seen - especially between D0.1ccm(SC) and D98(PTV) with a coefficient of determination of R2 = 0.81.Fig. 4

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.


Related in: MedlinePlus