Marie Fargier-Voiron1, Benoît Presles2, Pascal Pommier3, Simon Rit2, Alexandre Munoz3, Hervé Liebgott1, David Sarrut2, Marie-Claude Biston4. 1. CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Villeurbanne, France. 2. CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Villeurbanne, France; Léon Bérard Cancer Center, University of Lyon, France. 3. Léon Bérard Cancer Center, University of Lyon, France. 4. CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Villeurbanne, France; Léon Bérard Cancer Center, University of Lyon, France. Electronic address: marie-claude.biston@lyon.unicancer.fr.
Abstract
PURPOSE: To evaluate the impact of transabdominal probe pressure on prostate positioning with an intramodality ultrasound (US) image-guided-radiotherapy system and to quantify pressure variability over the treatment course. MATERIAL AND METHODS: 8 prostate cancer patients (group A) and 17 healthy volunteers underwent 3 consecutive US images with increasing probe pressure levels, and 1 CT acquisition for the group A only. Prostate positions were compared after manual registration of the first US image contour projected on 2 others. Group A's pressure levels were quantified by measuring skin-to-skin distances between corresponding CT-US images. The same methodology was used on paired CT/CBCT-US images acquired during treatments of 18 prostate cancer patients to determine whether the different pressure levels applied to the group A were close to the clinical practices and to quantify pressure variability along the treatment course. RESULTS: 84% of 3D prostate displacements were above 2mm for at least one pressure level. Probe pressures deliberately applied were similar to the ones observed clinically. The latter drastically varied between sessions. CONCLUSION: Even with an intramodality system, probe pressure can impact prostate localization because of the pressure variability along the treatment course. Therefore, margins should be expanded from 0.5 to 1.2mm to ensure treatment accuracy.
PURPOSE: To evaluate the impact of transabdominal probe pressure on prostate positioning with an intramodality ultrasound (US) image-guided-radiotherapy system and to quantify pressure variability over the treatment course. MATERIAL AND METHODS: 8 prostate cancerpatients (group A) and 17 healthy volunteers underwent 3 consecutive US images with increasing probe pressure levels, and 1 CT acquisition for the group A only. Prostate positions were compared after manual registration of the first US image contour projected on 2 others. Group A's pressure levels were quantified by measuring skin-to-skin distances between corresponding CT-US images. The same methodology was used on paired CT/CBCT-US images acquired during treatments of 18 prostate cancerpatients to determine whether the different pressure levels applied to the group A were close to the clinical practices and to quantify pressure variability along the treatment course. RESULTS: 84% of 3D prostate displacements were above 2mm for at least one pressure level. Probe pressures deliberately applied were similar to the ones observed clinically. The latter drastically varied between sessions. CONCLUSION: Even with an intramodality system, probe pressure can impact prostate localization because of the pressure variability along the treatment course. Therefore, margins should be expanded from 0.5 to 1.2mm to ensure treatment accuracy.
Authors: Bryan P Bednarz; Sydney Jupitz; Warren Lee; David Mills; Heather Chan; Timothy Fiorillo; James Sabitini; David Shoudy; Aqsa Patel; Jhimli Mitra; Shourya Sarcar; Bo Wang; Andrew Shepard; Charles Matrosic; James Holmes; Wesley Culberson; Michael Bassetti; Patrick Hill; Alan McMillan; James Zagzebski; L Scott Smith; Thomas K Foo Journal: Phys Med Date: 2021-07-01 Impact factor: 3.119
Authors: Sarah A Mason; Tuathan P O'Shea; Ingrid M White; Susan Lalondrelle; Kate Downey; Mariwan Baker; Claus F Behrens; Jeffrey C Bamber; Emma J Harris Journal: Med Phys Date: 2017-06-16 Impact factor: 4.071
Authors: Saskia M Camps; Davide Fontanarosa; Peter H N de With; Frank Verhaegen; Ben G L Vanneste Journal: Biomed Res Int Date: 2018-01-24 Impact factor: 3.411