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Projects / Programmes source: ARIS

Method for multimodal comparative analysis of 3D volumes, based on CT/MR images

Research activity

Code Science Field Subfield
3.04.00  Medical sciences  Oncology   

Code Science Field
B200  Biomedical sciences  Cytology, oncology, cancerology 
Keywords
volume contouring, magnetic resonance, interobserver differences
Evaluation (rules)
source: COBISS
Researchers (4)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  20658  PhD Cvetka Bilban-Jakopin  Medical sciences  Researcher  2008 - 2011  62 
2.  24481  Rihard Hudej  Oncology  Researcher  2008 - 2011  50 
3.  20657  PhD Robert Hudej  Oncology  Head  2008 - 2011  90 
4.  21727  MSc Primož Petrič  Oncology  Researcher  2008 - 2011  122 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0302  Institute of Oncology Ljubljana  Ljubljana  5055733000  15,493 
Abstract
In this project we propose the development of multimodal interobserver analysis of contoured volumes, that would enable the analysis on the level of whole volumes and on the level of individual voxels inside the contoured volumes. The aim of the project is to develop a software that would be able to read CT and MR images, import contoured volumes and with different methods analyze the interobserver differences. The methodology of the contoured volume analysis will be based on two levels: 1. Comparison on the global level: a. Size of contoured volumes b. Volumetric conformity index 2. Comparison on the local level: a. Conformity index on separate CT/MR slices b. Frequency of volume overlap in each voxel inside contoured volumes c. Measurment of smallest distances between contoured volumes on each CT/MR slice and for each voxel inside contoured volumes. The software will be able to overlap the results with CT/MR images. This option will serve as an efficient tool for interobserver difference localization and identification for these differences. It will be possible to use the software as: - quality control inside the radiotherapeutic centres - efficient learning tool for future contouring recommendation users - method for data analysis in future research projects of broader field of radiotherapy.
Significance for science
Capability for local dose escalation afforded by 3D image guided barchytherapy exceeds any other radiotherapy modality. Accurate contouring of the target volume and organs at risk therefore represents a precondition for its success. Systematic analysis of contouring variations and development of strategies for their reduction are crucial for further development of modern brachytherapy. The Contour Analysis Tool (CAT) software application that was developed within the frame of this project enables a comprehensive assessment of interobserver or intermodality delineation variability both on the volumetric, as well as on topographic level. Majority of published analyses in this field deal mainly with volumetric intercomaparisons, whereas detailed topographic mapping of contour deviations was limited to a few research groups and mainly to the field of external beam radiotherapy up to now. By using CAT, the magnitude and topographic distribution of contouring uncertainties in brachytherapy can be quantified, enabling a deeper understanging of potentials and limitiations of different imaging modalities used. In addition, eventual predilection regions for disagreement can be identified and the time courses and shapes of typical brachytherapist's learning curves in different clnical settings can be described. These basic scientific questions with direct applicability in clinical practice have not been addressed systematically in the past. After testing with known phantom geometries, CAT has been tested already in several research settings, including different contouring workshops, organized in the frame of the Gyn GEC ESTRO Network, during Gynae Resolution workshop, organized at the General Hospital of Vienna, Austria and within an EMBRACE contouring workshop at Utrecht Medical Center, the Netherlands. In addition, CAT has been utilized in a prospective fashion in two interobserver contouring studies, performed at the Institute of Oncology Ljubljana at the end of 2009 and beginning of 2010. Importantly, CAT is being applied as the main methodological platform of a large, prospective multi-center contouring study in cervix cancer brachytherapy, which is an important part of the EMBRACE study (www.embracestudy.dk). Results of the above mentioned and future scientific research, enabled by the CAT software are expected to give additional mommentum to the rapidly evolving field of 3D image guided gynaecological brachytherapy.
Significance for the country
The incidence of malignancies that require treatment with radiotherapy, including brachytherapy, continues to increase in Slovenia and other parts of the world. Scientific results, obtained in systematic interobserver studies using CAT as the methodological package, will improve our ability for highly conformal dose escalation in the target volume while avoiding excessive irradiation of the surrounding normal tissues. This is expected to be translated into improved clinical results with an increased chance of uncomplicated cure, having also a direct beneficial impact on the public healthcare situation, and reduction of costs, connected to challenging and usually ineffective treatment of cancer recurrence. In fact, improving delineation accuracy is a precondition for further developments of the high-tech brachytherapy approaches and by developing the methodology of CAT software, slovenian research partners are taking the international initiative in this important topic. In addition to the expected improvement of clinical results, unifying the contouring process will improve the ability of different oncological centres to record, report and compare dosimetric and clinical data – to speak a common language. Importantly, one of very promising areas of application of CAT software is the education of radiotherapy and radiology residents. Implementation of the CAT software in an international multi-institutional prospective study setting, such as the EMBRACE study (www.embracestudy.dk) represents an important means of affirmation of Slovenian research potential on the international level and assures firm connections with the opinion leading research groups for the future scientific and clinical cooperation.
Most important scientific results Annual report 2008, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2008, final report, complete report on dLib.si
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