Radiothérapie guidée par l'image

Crevoisier, R. de; Isambert, A.; Lisbona, A.; Bodez, V.; Marguet, Maud; Lafay, F; Remonnay, Raphaël; Jl, Lagrange

doi:10.1016/j.canrad.2007.08.002

Cited by 22 publications

(2 citation statements)

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“…In clinical trials, gold fiducial markers were implanted in the prostate to tune the table position before each radiation beam. Yet, it is unclear if a cone-beam computed tomography (CBCT) should be performed before each beam to monitor a possible variation of the organs at risk (OARs) fullness [3][4][5], especially when performed with hyaluronic acid spacer. The present technical note was designed to assess this question.…”

Section: Introductionmentioning

confidence: 99%

CBCT evaluation of inter- and intra-fraction motions during prostate stereotactic body radiotherapy: a technical note

et al. 2020

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Background: In most clinical trials, gold fiducial markers are implanted in the prostate to tune the table position before each radiation beam. Yet, it is unclear if a cone-beam computed tomography (CBCT) should be performed before each beam to monitor a possible variation of the organs at risk (OARs) fullness, especially in case of rectoprostatic spacer implantation. The present study aimed at assessing the inter-and intra-fraction movements of prostate, bladder and rectum in patients implanted with a hyaluronic acid spacer and undergoing prostate stereotactic body radiotherapy (SBRT). Methods: Data about consecutive patients undergoing prostate SBRT were prospectively collected between 2015 and 2019. Inter-and intra-fraction prostate displacements and volume variation of organs at risk (OARs) were assessed with CBCTs. Results: Eight patients were included. They underwent prostate SBRT (37.5Gy, 5 fractions of 7.5Gy) guided by prostate gold fiducial markers. Inter-fraction variation of the bladder volume was insignificant. Intra-fraction mean increase of the bladder volume was modest (29 cc) but significant (p < 0.001). Both inter-and intra-fraction variations of the rectum volume were insignificant but for one patient. He had no rectal toxicity. The magnitude of table displacement necessary to match the prostate gold fiducial marker frequently exceeded the CTV/PTV margins (0.4 cm) before the first (35%) and the second arc (15%). Inter-and intra-fraction bladder and rectum volume variations did not correlate with prostate displacement. Conclusion: Major prostate position variations were reported. In-room kV fiducial imaging before each arc seems mandatory. Intra-fraction imaging of the OARs appears unnecessary. We suggest that only one CBCT is needed before the first arc.

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Section: Introductionmentioning

confidence: 99%

CBCT evaluation of inter- and intra-fraction motions during prostate stereotactic body radiotherapy: a technical note

et al. 2020

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“…La radiothérapie guidée par l'image (IGRT) s'est peu à peu imposée dans le paysage de la radiothérapie conformationnelle avec modulation d'intensité (RCMI), dans le but d'obtenir une précision accrue du positionnement du patient, et plus précisément de la tumeur, sous la machine de traitement. L'IGRT repose sur l'acquisition régulière d'images lors des séances de traitement, ces images pouvant être en deux, trois, voire quatre dimensions (2D-3D-4D), selon les localisations anatomiques (1)(2)(3). La tomographie conique, plus couramment appelée CBCT (Cone Beam Computed Tomography), est la modalité d'imagerie 3D la plus répandue pour les besoins de l'IGRT.…”

Section: Introductionunclassified

Calcul de dose de radiothérapie à partir de tomographies coniques : état de l’art

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Lafond

et al. 2018

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En radiothérapie externe, la planification dosimétrique est basée sur des images tomodensitométriques (CT). Une conversion des nombres Hounsfield, contenus dans ces images, en densité électronique (ou physique) est nécessaire pour réaliser un calcul de dose tenant compte des hétérogénéités. Dans un processus d'IGRT (Image Guided Radiotherapy), le Cone Beam CT (CBCT) est utilisé pour visualiser et recaler les structures anatomiques. Le calcul de dose sur CBCT est attrayant dans une perspective de «rapporter» et de «monitorer» la dose délivrée à la séance, notamment dans un contexte de radiothérapie adaptative guidée par la dose. La précision attendue du calcul de dose sur imagerie CBCT est contrainte par la qualité image, la variation des nombres Hounsfield et les dimensions restreintes du volume d'acquisition. L'analyse de la littérature permet d'identifier trois types de stratégies de calcul de dose sur CBCT : l'utilisation de courbes de correspondance entre nombres Hounsfield et densités, l'affectation de densités à différentes structures segmentées et l'utilisation du recalage déformable entre les images CT et CBCT. Les résultats de la littérature montrent des écarts entre les doses calculées sur CBCT et celles calculées sur CT souvent inférieurs à 3 %, toutes méthodes confondues. Néanmoins, le calcul de dose sur images CBCT nécessite une certaine prudence car ces écarts peuvent atteindre 10 % avec une méthode inadaptée. Bien qu'aucune méthode de calcul de dose sur CBCT ne se détache nettement des autres, certaines se montrent prometteuses et nécessitent d'être associées à une automatisation pour une mise en oeuvre en routine clinique.

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Assessment of the intrinsic radiosensitivity of glioma cells and monitoring of metabolite ratio changes after irradiation by 14.7-T high-resolution¹H MRS

et al. 2014

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Gliomas are the most common type of primary brain tumor. Radiation therapy (RT) is the primary adjuvant treatment to eliminate residual tumor tissue after surgery. However, the current RT guided by conventional imaging is unsatisfactory. A fundamental question is whether it is possible to further enhance the effectiveness and efficiency of RT based on individual radiosensitivity. In this research, to probe the correlation between radiosensitivity and the metabolite characteristics of glioma cells in vitro, a perchloric acid (PCA) extracting method was used to obtain water-soluble metabolites [such as N-acetylaspartate (NAA), choline (Cho), creatine (Cr) and succinate (Suc)]. Spectral patterns from these processed water-soluble metabolite samples were acquired by in vitro 14.7-T high-resolution ¹H MRS. Survival fraction analysis was performed to test the intrinsic radiosensitivity of glioma cell lines. Good ¹H MRS of PCA extracts from glioma cells was obtained. The radiosensitivity of glioma cells correlated positively with the Cho/Cr and Cho/NAA ratios, but negatively with the Suc/Cr ratio. Irradiation of the C6 cell line at different X-ray dosages led to changes in metabolite ratios and apoptotic rates. A plateau phase of metabolite ratio change and a decrease in apoptotic rate were found in the C6 cell line. We conclude that in vitro high-resolution ¹H MRS possesses the sensitivity required to detect subtle biochemical changes at the cellular level. ¹H MRS may aid in the assessment of the individual radiosensitivity of brain tumors, which is pivotal in the identification of the biological target volume.

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Radiothérapie guidée par l'image

Cited by 22 publications

References 71 publications

CBCT evaluation of inter- and intra-fraction motions during prostate stereotactic body radiotherapy: a technical note

CBCT evaluation of inter- and intra-fraction motions during prostate stereotactic body radiotherapy: a technical note

Calcul de dose de radiothérapie à partir de tomographies coniques : état de l’art

Assessment of the intrinsic radiosensitivity of glioma cells and monitoring of metabolite ratio changes after irradiation by 14.7-T high-resolution¹H MRS

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Radiothérapie guidée par l'image

Cited by 22 publications

References 71 publications

CBCT evaluation of inter- and intra-fraction motions during prostate stereotactic body radiotherapy: a technical note

CBCT evaluation of inter- and intra-fraction motions during prostate stereotactic body radiotherapy: a technical note

Calcul de dose de radiothérapie à partir de tomographies coniques : état de l’art

Assessment of the intrinsic radiosensitivity of glioma cells and monitoring of metabolite ratio changes after irradiation by 14.7-T high-resolution1H MRS

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Assessment of the intrinsic radiosensitivity of glioma cells and monitoring of metabolite ratio changes after irradiation by 14.7-T high-resolution¹H MRS