Evaluation of intensity modulated radiation therapy dose painting for localized prostate cancer using 68 Ga-HBED-CC PSMA-PET/CT: A planning study based on histopathology reference

AbstractPurposeTo demonstrate the feasibility and to evaluate the tumour control probability (TCP) and normal tissue complication probability (NTCP) of IMRT dose painting using 68Ga-HBED-CC PSMA PET/CT for target delineation in prostate cancer (PCa).Methods and materials10 patients had PSMA PET/CT scans prior to prostatectomy. GTV-PET was generated on the basis of an intraprostatic SUVmax of 30%. Two IMRT plans were generated for each patient: Plan77 which consisted of whole-prostate IMRT to 77Gy, and Plan95 which consisted of whole-prostate IMRT to 77Gy and a simultaneous integrated boost to the GTV-PET up to 95Gy (35 fractions). The feasibility of these plans was judged by their ability to adhere to the FLAME trial protocol. TCP-histo/-PET were calculated on co-registered histology (GTV-histo) and GTV-PET, respectively. NTCPs for rectum and bladder were calculated.ResultsAll plans reached prescription doses whilst adhering to dose constraints. In Plan77 and Plan95 mean doses in GTV-histo were 75.8±0.3Gy and 96.9±1Gy, respectively. Average TCP-histo values for Plan77 and Plan95 were 70% (range: 15–97%), and 96% (range: 78–100%, p77 and Plan95 were 55% (range: 27–82%), and 100% (range: 99–100%, p95 (p=0.25). There were no significant differences in rectal (p=0.563) and bladder (p=0.3) NTCPs.ConclusionsIMRT dose painting using PSMA PET/CT was technically feasible and resulted in significantly higher TCPs without higher NTCPs

Bone mass measurement improvement in micro-CT taking into account the physical phenomena

Suite à l'allongement de la survie des patients atteints de la mucoviscidose (CF), des études ont montré la présence d'une perte osseuse chez les patients CF. Dans ce travail de thèse, une étude de l'évolution de la densité minérale osseuse chez des souris atteintes de mucoviscidose a été effectuée en utilisant un système de micro-tomodensitométrie X. Afin d'améliorer les précisions des mesure, deux méthodes de correction de deux phénomènes physiques ont été appliquées. La première méthode est une correction du durcissement de faisceau X et basée sur une segmentation de l'objet reconstruit après une première reconstruction et en utilisant des courbes d'atténuations précalculées. La deuxième méthode est une méthode de correction de la diffusion des rayons dans l'animal basée sur l'estimation des projections des diffusés en utilisant des noyaux de diffusion précalculées. Des améliorations au niveau de la qualité de l'image et les mesures de densité osseuses ont été obtenues.Due to the increased survival of the patients with cystic fibrosis (CF), studies showed the presence of osteoporosis in CF patients. In this work, a follow-up study of the bone mineral density (BMD) formice with CF is done using a micro-CT system. In order to perform accurately the measurements, weapplied two correction methods aiming to reduce artifacts in CT images. The first correction method is abeam hardening correction technique based on a post-reconstruction procedure and usingpre-calculated linearization curves. The second correction method is a hybrid elimination approach of scatter radiations from acquisition projections and based on the use of pre-calculated scatter kernels,simulated analytically. Improvements have been shown concerning image quality (contrast, artifactsreduction) and BMD measurements

Bone mass measurement improvement in micro-CT taking into account the physical phenomena

Suite à l'allongement de la survie des patients atteints de la mucoviscidose (CF), des études ont montré la présence d'une perte osseuse chez les patients CF. Dans ce travail de thèse, une étude de l'évolution de la densité minérale osseuse chez des souris atteintes de mucoviscidose a été effectuée en utilisant un système de micro-tomodensitométrie X. Afin d'améliorer les précisions des mesure, deux méthodes de correction de deux phénomènes physiques ont été appliquées. La première méthode est une correction du durcissement de faisceau X et basée sur une segmentation de l'objet reconstruit après une première reconstruction et en utilisant des courbes d'atténuations précalculées. La deuxième méthode est une méthode de correction de la diffusion des rayons dans l'animal basée sur l'estimation des projections des diffusés en utilisant des noyaux de diffusion précalculées. Des améliorations au niveau de la qualité de l'image et les mesures de densité osseuses ont été obtenues.Due to the increased survival of the patients with cystic fibrosis (CF), studies showed the presence of osteoporosis in CF patients. In this work, a follow-up study of the bone mineral density (BMD) formice with CF is done using a micro-CT system. In order to perform accurately the measurements, weapplied two correction methods aiming to reduce artifacts in CT images. The first correction method is abeam hardening correction technique based on a post-reconstruction procedure and usingpre-calculated linearization curves. The second correction method is a hybrid elimination approach of scatter radiations from acquisition projections and based on the use of pre-calculated scatter kernels,simulated analytically. Improvements have been shown concerning image quality (contrast, artifactsreduction) and BMD measurements

Amélioration du calcul de la masse osseuse par micro-tomodensitométrie X : prise en compte des phénomènes physiques

Due to the increased survival of the patients with cystic fibrosis (CF), studies showed the presence of osteoporosis in CF patients. In this work, a follow-up study of the bone mineral density (BMD) formice with CF is done using a micro-CT system. In order to perform accurately the measurements, weapplied two correction methods aiming to reduce artifacts in CT images. The first correction method is abeam hardening correction technique based on a post-reconstruction procedure and usingpre-calculated linearization curves. The second correction method is a hybrid elimination approach of scatter radiations from acquisition projections and based on the use of pre-calculated scatter kernels,simulated analytically. Improvements have been shown concerning image quality (contrast, artifactsreduction) and BMD measurements.Suite à l'allongement de la survie des patients atteints de la mucoviscidose (CF), des études ont montré la présence d'une perte osseuse chez les patients CF. Dans ce travail de thèse, une étude de l'évolution de la densité minérale osseuse chez des souris atteintes de mucoviscidose a été effectuée en utilisant un système de micro-tomodensitométrie X. Afin d'améliorer les précisions des mesure, deux méthodes de correction de deux phénomènes physiques ont été appliquées. La première méthode est une correction du durcissement de faisceau X et basée sur une segmentation de l'objet reconstruit après une première reconstruction et en utilisant des courbes d'atténuations précalculées. La deuxième méthode est une méthode de correction de la diffusion des rayons dans l'animal basée sur l'estimation des projections des diffusés en utilisant des noyaux de diffusion précalculées. Des améliorations au niveau de la qualité de l'image et les mesures de densité osseuses ont été obtenues

A fast experimental beam hardening correction method for accurate bone mineral measurements in 3D μCT imaging system

International audienceBone mineral density plays an important role in the determinationof bone strength and fracture risks. Consequently,it is very important to obtain accurate bone mineral densitymeasurements. The microcomputerized tomography systemprovides 3D information about the architectural propertiesof bone. Quantitative analysis accuracy is decreased by thepresence of artefacts in the reconstructed images, mainly dueto beam hardening artefacts (such as cupping artefacts). Inthis paper, we introduced a new beam hardening correctionmethod based on a postreconstruction technique performedwith the use of off-line water and bone linearization curvesexperimentally calculated aiming to take into account thenonhomogeneity in the scanned animal. In order to evaluatethe mass correction rate, calibration line has been carriedout to convert the reconstructed linear attenuation coefficientinto bone masses. The presented correction method was thenapplied on a multimaterial cylindrical phantom and on mouseskeleton images. Mass correction rate up to 18% between uncorrectedand corrected images were obtained as well as aremarkable improvement of a calculated mouse femur masshas been noticed. Results were also compared to those obtainedwhen using the simple water linearization techniquewhich does not take into account the nonhomogeneity in theobject

Focal dose escalation for prostate cancer using 68Ga-HBED-CC PSMA PET/CT and MRI: a planning study based on histology reference

Abstract Background Focal radiation therapy has gained of interest in treatment of patients with primary prostate cancer (PCa). The question of how to define the intraprostatic boost volume is still open. Previous studies showed that multiparametric MRI (mpMRI) or PSMA PET alone could be used for boost volume definition. However, other studies proposed that the combined usage of both has the highest sensitivity in detection of intraprostatic lesions. The aim of this study was to demonstrate the feasibility and to evaluate the tumour control probability (TCP) and normal tissue complication probability (NTCP) of radiation therapy dose painting using 68Ga-HBED-CC PSMA PET/CT, mpMRI or the combination of both in primary PCa. Methods Ten patients underwent PSMA PET/CT and mpMRI followed by prostatectomy. Three gross tumour volumes (GTVs) were created based on PET (GTV-PET), mpMRI (GTV-MRI) and the union of both (GTV-union). Two plans were generated for each GTV. Plan95 consisted of whole-prostate IMRT to 77 Gy in 35 fractions and a simultaneous boost to 95 Gy (Plan95PET/Plan95MRI/Plan95union). Plan80 consisted of whole-prostate IMRT to 76 Gy in 38 fractions and a simultaneous boost to 80 Gy (Plan80PET/Plan80MRI/Plan80union). TCPs were calculated for GTV-histo (TCP-histo), which was delineated based on PCa distribution in co-registered histology slices. NTCPs were assessed for bladder and rectum. Results Dose constraints of published protocols were reached in every treatment plan. Mean TCP-histo were 99.7% (range: 97%–100%) and 75.5% (range: 33%–95%) for Plan95union and Plan80union, respectively. Plan95union had significantly higher TCP-histo values than Plan95MRI (p = 0.008) and Plan95PET (p = 0.008). Plan80union had significantly higher TCP-histo values than Plan80MRI (p = 0.012), but not than Plan80PET (p = 0.472). Plan95MRI had significantly lower NTCP-rectum than Plan95union (p = 0.012). No significant differences in NTCP-rectum and NTCP-bladder were observed for all other plans (p > 0.05). Conclusions IMRT dose escalation on GTVs based on mpMRI, PSMA PET/CT and the combination of both was feasible. Boosting GTV-union resulted in significantly higher TCP-histo with no or minimal increase of NTCPs compared to the other plans

Selective Photooxidation Reactions using Water-Soluble Anthraquinone Photocatalysts

The aerobic organocatalytic oxidation of alcohols was achieved by using water-soluble sodium anthraquinone sulfonate. Under visible-light activation, this catalyst mediated the aerobic oxidation of alcohols to aldehydes and ketones. The photo-oxyfunctionalization of alkanes was also possible under these conditions.BT/Biocatalysi

Additional file 3: of Focal dose escalation for prostate cancer using 68Ga-HBED-CC PSMA PET/CT and MRI: a planning study based on histology reference

A. Additional information on TCP calculation / B. Additional information on NTCP calculation. (PDF 278 kb

Additional file 1: of Focal dose escalation for prostate cancer using 68Ga-HBED-CC PSMA PET/CT and MRI: a planning study based on histology reference

Table S1. Patient characteristics. (PDF 106 kb