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

Toussaint, A and Richter, A and Mantel, F and Flickinger, JC and Grills, IS and Tyagi, N and Sahgal, A and Letourneau, D and Sheehan, JP and Schlesinger, DJ and Gerszten, PC and Guckenberger, M (2016) Variability in spine radiosurgery treatment planning - results of an international multi-institutional study. Radiation Oncology, 11 (1).

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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.


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Item Type: Article
Status: Published
CreatorsEmailPitt UsernameORCID
Toussaint, A
Richter, A
Mantel, F
Flickinger, JCjflickin@pitt.eduJFLICKIN
Grills, IS
Tyagi, N
Sahgal, A
Letourneau, D
Sheehan, JP
Schlesinger, DJ
Gerszten, PCgerszten@pitt.eduGERSZTEN
Guckenberger, M
Date: 18 April 2016
Date Type: Publication
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Journal or Publication Title: Radiation Oncology
Volume: 11
Number: 1
DOI or Unique Handle: 10.1186/s13014-016-0631-9
Institution: University of Pittsburgh
Schools and Programs: School of Medicine > Neurological Surgery
School of Medicine > Radiation Oncology
Refereed: Yes
Date Deposited: 22 Jul 2016 17:02
Last Modified: 22 Jun 2021 15:55


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