An image-based method to synchronize cone-beam CT and optical surface tracking

open5siThe integration of in-room X-ray imaging and optical surface tracking has gained increasing importance in the field of image guided radiotherapy (IGRT). An essential step for this integration consists of temporally synchronizing the acquisition of X-ray projections and surface data. We present an image-based method for the synchronization of cone-beam computed tomography (CBCT) and optical surface systems, which does not require the use of additional hardware. The method is based on optically tracking the motion of a component of the CBCT/gantry unit, which rotates during the acquisition of the CBCT scan. A calibration procedure was implemented to relate the position of the rotating component identified by the optical system with the time elapsed since the beginning of the CBCT scan, thus obtaining the temporal correspondence between the acquisition of X-ray projections and surface data. The accuracy of the proposed synchronization method was evaluated on a motorized moving phantom, performing eight simultaneous acquisitions with an Elekta Synergy CBCT machine and the AlignRT optical device. The median time difference between the sinusoidal peaks of phantom motion signals extracted from the synchronized CBCT and AlignRT systems ranged between -3.1 and 12.9 msec, with a maximum interquartile range of 14.4 msec. The method was also applied to clinical data acquired from seven lung cancer patients, demonstrating the potential of the proposed approach in estimating the individual and daily variations in respiratory parameters and motion correlation of internal and external structures. The presented synchronization method can be particularly useful for tumor tracking applications in extracranial radiation treatments, especially in the field of patient-specific breathing models, based on the correlation between internal tumor motion and external surface surrogates.Fassi, Aurora; Schaerer, Joël; Riboldi, Marco; Sarrut, David; Baroni, GuidoFassi, Aurora; Schaerer, Joël; Riboldi, Marco; Sarrut, David; Baroni, Guid

Computed tomographic atlas for the new international lymph node map for lung cancer: A radiation oncologist perspective

International audiencePurpose : To develop a reproducible definition for each mediastinal lymph node station based on the new TNM classification for lung cancer. Methods and Materials : This paper proposes an atlas using the new international lymph node map used in the seventh edition of the TNM classification for lung cancer. Four radiation oncologists and 1 diagnostic radiologist were involved in the project to put forward a reproducible radiologic description for the lung lymph node stations.Results : The International Association for the Study of Lung Cancer lymph node definitions for stations 1 to 11 have been described and illustrated on axial computed tomographic scan images using a certified radiotherapy planning system. Conclusions : This atlas will assist both diagnostic radiologists and radiation oncologists in accurately defining the lymph node stations on computed tomographic scan in patients diagnosed with lung cancer

Is abdominal compression useful in lung stereotactic body radiation therapy? A 4DCT and dosimetric lobe-dependent study

International audiencePurpose : To determine the usefulness of abdominal compression in lung stereotactic body radiation therapy (SBRT) depending on lobe tumor location.Materials and methods : Twenty-seven non-small cell lung cancer patients were immobilized in the Stereotactic Body Frame™ (Elekta). Eighteen tumors were located in an upper lobe, one in the middle lobe and nine in a lower lobe (one patient had two lesions). All patients underwent two four-dimensional computed tomography (4DCT) scans, with and without abdominal compression. Three-dimensional tumor motion amplitude was determined using manual landmark annotation. We also determined the internal target volume (ITV) and the influence of abdominal compression on lung dose-volume histograms. Results : The mean reduction of tumor motion amplitude was 3.5 mm (p = 0.009) for lower lobe tumors and 0.8 mm (p = 0.026) for upper/middle lobe locations. Compression increased tumor motion in 5 cases. Mean ITV reduction was 3.6 cm3 (p = 0.039) for lower lobe and 0.2 cm3 (p = 0.048) for upper/middle lobe lesions. Dosimetric gain of the compression for lung sparing was not clinically relevant. Conclusions : The most significant impact of abdominal compression was obtained in patients with lower lobe tumors. However, minor or negative effects of compression were reported for other patients and lung sparing was not substantially improved. At our institute, patients with upper or middle lobe lesions are now systematically treated without compression and the usefulness of compression for lower lobe tumors is evaluated on an individual basis

Extraction of the respiratory signal from cone-beam projections for 4D CT imaging

To be efficient, the treatement of the lung cancers with radiation therapy must take into account the respiratory motion. The knowledge of this motion requires the acquisition of 4D computed tomography (CT) images. The free-breathing thorax 4D CT images currently acquired use gated or respiratory-correlated methods. These methods involve the collection of a respiratory signal during the acquisition of data in order to sort them into different groups. The quality of the 4D CT image thus depends on an accurate description by the signal of the position of the thorax in the respiratory cycle. The signal is generally acquired by independent measurements of densitometric data (spirometer, thermometer, ...). We propose to extract it directly from the sequence of 2D cone-beam (CB) projections acquired around the free-breathing thorax. Our method derives the motion between two consecutive 2D CB projections using a block matching algorithm. Blocks are positioned around points of interest constituting a regular sampling of the 2D CB projections. A unidimensional signal is derived from the trajectory of each block in the sequence after projection. Aggregation of a subset of selected makes it possible to derive the respiratory signal during the acquisition time. Our method is validated quantitatively on simulated data and qualitatively on real data. On simulated data, we obtain a respiratory signal with 97.5 % linear correlation with the reference. On real data, the extracted signal allow to reconstruct 4D CT images for comparison with the blurred 3D CT image obtained without taking into account the respiratory motion.Le traitement des cancers des poumons par radiothérapie doit prendre en compte les mouvements respiratoires pour être efficace. La connaissance de ce mouvement passe par l'obtention d'images tomodensitométriques (TDM) 4D. Les images TDM 4D du thorax en respiration libre acquises actuellement utilisent les méthodes de type gated ou respiration-correlated. Ces méthodes nécessitent un signal respiratoire, recueilli pendant l'acquisition des données, pour trier celles-ci en différents groupes. La qualité de l'image TDM 4D dépend alors d'une description correcte, par le signal respiratoire, de la position du thorax dans le cycle respiratoire au cours de l'acquisition. Ce signal est généralement acquis par une mesure indépendante des données densitométriques (spiromètre, thermomètre,...). Nous proposons de l'extraire directement de la séquence de projections cone-beam (CB) 2D acquises autour du thorax en respiration libre. Notre méthode extrait le mouvement entre deux projections CB 2D consécutives par un algorithme de mise en correspondance de blocs. Ces blocs sont positionnés autour de points d'intérêt constituant un sous-échantillonnage régulier des projections CB 2D. Nous déduisons de la trajectoire de chaque bloc dans la séquence un signal unidimensionnel après projection. Une sélection d'un sous-ensemble de ces signaux nous permet d'obtenir, après agrégation, le signal respiratoire pendant le temps de l'acquisition. Notre méthode est validée quantitativement sur données simulées et qualitativement sur données réelles. Sur données simulées, nous obtenons un signal respiratoire corrélé linéairement à 97,5 % avec la référence. Sur données réelles, le signal extrait nous permet de reconstruire l'image TDM 4D d'un patient que l'on compare à l'image TDM 3D floue, obtenue sans prise en compte du mouvement respiratoire

2012 Activity Report of the Regional Research Programme on Hadrontherapy for the ETOILE Center

2012 is the penultimate year of financial support by the CPER 2007-2013 for ETOILE's research program, sustained by the PRRH at the University Claude Bernard. As with each edition we make the annual review of the research in this group, so active for over 12 years now. Over the difficulties in the decision-making process for the implementation of the ETOILE Center, towards which all our efforts are focussed, some "themes" (work packages) were strengthened, others have progressed, or have been dropped. This is the case of the eighth theme (technological developments), centered around the technology for rotative beam distribution heads (gantries) and, after being synchronized with the developments of ULICE's WP6, remained so by ceasing its activities, coinciding also with the retirement of its historic leader at IPNL, Marcel Bajard. Topic number 5 ("In silico simulations") has suffered the departure of its leader, Benjamin Ribba, although the work has still been provided by Branka Bernard, a former postdoctoral fellow in Lyon Sud, and now back home in Croatia, still in contract with UCBL for the ULICE project. Aside from these two issues (and the fact that the theme "Medico-economical simulations" is now directly linked to the first one ("Medical Project"), the rest of the teams are growing, as evidenced by the publication statistics at the beginning of this report. This is obviously due to the financial support of our always faithful regional institutions, but also to the synergy that the previous years, the European projects, the arrival of the PRIMES LabEx, and the national France Hadron infrastructure have managed to impulse. The Rhone-Alpes hadron team, which naturally includes the researchers of LPC at Clermont, should also see its influence result in a strong presence in France Hadron's regional node, which is being organized. The future of this regional research is not yet fully guaranteed, especially in the still uncertain context of ETOILE, but the tracks are beginning to emerge to allow past and present efforts translate into a long future that we all want to see established. Each of the researchers in PRRH is aware that 2013 will be (and already is) the year of great challenge : for ETOILE, for the PRRH, for hadron therapy in France, for French hadrontherapy in Europe (after the opening and beginning of treatments in the German [HIT Heidelberg, Marburg], Italian [CNAO, Pavia] and Austrian [MedAustron, Wien Neuerstadt]) centers. Let us meet again in early 2014 for a comprehensive review of the past and a perspective for the future ..

Briser le mythe de la « jungle qui tue » : analyse du rôle des intermédiaires dans la traversée du Darién (frontière Colombie-Panama)

Un « enfer vert » ; une « jungle qui tue » : la sémantique des discours politiques et médiatiques responsabilise et criminalise la jungle du Darién en la rendant actrice de la migration. Toutefois, cela ne reste qu’un environnement, hostile certes, mais ne pouvant porter la responsabilité de la mort de milliers de migrants qui la traversent quotidiennement pour rejoindre les États-Unis. Cet article interroge cet espace mythifié au-delà de sa topographie et de ses représentations en analysant les rôles des intermédiaires dans la traversée de la jungle à des échelles locales, nationales et internationales. Ces pratiques parfois criminalisées sont recouvertes de représentations qui occultent la diversité des intermédiaires tout en délaissant les capacités agentives des migrants dans leur propre traversée. Ainsi, en s’appuyant sur l’ethnographie de trois points stratégiques sur la route et une approche géographique, cet article a pour ambition de complexifier la figure réductrice de la dynamique migratoire comme partagée entre un gouvernement répressif d’un côté, et des passeurs « méchants » de l’autre.A “green hell”; a “jungle that kills”: The semantics of political and media discourse holds the Darien jungle accountable and criminalizes it as a central actor in migration. However, even if the environment is certainly hostile, it is incapable of bearing the responsibility for the deaths of thousands of migrants who traverse it daily to reach the United States. This article questions this mythologized space of the Darien beyond its topography and representations by analyzing the roles of intermediaries in the jungle crossing at local, national, and international levels. These sometimes criminalized practices are covered with representations that obscure the diversity of intermediaries while neglecting the agency of migrants in their own journeys. Thus, drawing on ethnography of three strategic points on the route and a geographical approach, this article aims to complexify the reductionist images of the migratory dynamics shared between a repressive government on one side and “evil” traffickers on the other.Un «infierno verde»; una «selva asesina»: la semántica de los discursos políticos y mediáticos responsabiliza y criminaliza la jungla de Darién al convertirla en protagonista de la migración. Sin embargo, esto no es más que un entorno, ciertamente hostil, pero que no puede cargar con la responsabilidad de la muerte de miles de migrantes que la atraviesan a diario para llegar a los Estados Unidos. Este artículo cuestiona este espacio mitificado más allá de su topografía y sus representaciones, analizando los roles de los intermediarios en el cruce de la selva a nivel local, nacional e internacional. Estas prácticas, a veces criminalizadas, están cubiertas de representaciones que ocultan la diversidad de los intermediarios, al tiempo que descuidan las capacidades agentivas de los migrantes en su propia travesía. Así, basándose en la etnografía de tres puntos estratégicos en la ruta y un enfoque geográfico, este artículo tiene como objetivo complejizar la figura reduccionista de la dinámica migratoria compartida entre un gobierno represivo de un lado y traficantes «malvados» del otro

A first-in-human study investigating biodistribution, safety and recommended dose of a new radiolabeled MAb targeting FZD10 in metastatic synovial sarcoma patients

Background: Synovial Sarcomas (SS) are rare tumors occurring predominantly in adolescent and young adults with a dismal prognosis in advanced phases. We report a first-in-human phase I of monoclonal antibody (OTSA-101) targeting FZD10, overexpressed in most SS but not present in normal tissues, labelled with radioisotopes and used as a molecular vehicle to specifically deliver radiation to FZD10 expressing SS lesions. Methods: Patients with progressive advanced SS were included. In the first step of this trial, OTSA-101 in vivo biodistribution and lesions uptake were evaluated by repeated whole body planar and SPECT-CT scintigraphies from H1 till H144 after IV injection of 187 MBq of 111In-OTSA-101. A 2D dosimetry study also evaluated the liver absorbed dose when using 90Y-OTSA-101. In the second step, those patients with significant tumor uptake were randomized between 370 MBq (Arm A) and 1110 MBq (Arm B) of 90Y-OTSA-101 for radionuclide therapy. Results: From January 2012 to June 2015, 20 pts. (median age 43 years [21–67]) with advanced SS were enrolled. Even though 111In-OTSA-101 liver uptake appeared to be intense, estimated absorbed liver dose was less than 20 Gy for each patient. Tracer intensity was greater than mediastinum in 10 patients consistent with sufficient tumor uptake to proceed to treatment with 90Y-OTSA-101: 8 were randomized (Arm A: 3 patients and Arm B: 5 patients) and 2 were not randomized due to worsening PS. The most common Grade ≥ 3 AEs were reversible hematological disorders, which were more frequent in Arm B. No objective response was observed. Best response was stable disease in 3/8 patients lasting up to 21 weeks for 1 patient. Conclusions: Radioimmunotherapy targeting FZD10 is feasible in SS patients as all patients presented at least one lesion with 111In-OTSA-101 uptake. Tumor uptake was heterogeneous but sufficient to select 50% of pts. for 90Y-OTSA-101 treatment. The recommended activity for further clinical investigations is 1110 MBq of 90Y-OTSA-101. However, because of hematological toxicity, less energetic particle emitter radioisopotes such as Lutetium 177 may be a better option to wider the therapeutic index. Trial registration: The study was registered on the NCT01469975 ( https://clinicaltrials.gov/ct2/show/NCT01469975 ) website with a registration code NCT01469975 on November the third, 2011