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The development of alternative therapies for melanoma treatment is of great interest as long-term tumour regression is not achieved with new targeted chemotherapies on selected patients. We previously demonstrated that radioiodinated heteroarylcarboxamide ([131I]ICF01012) induced a strong anti-tumoural effect by inhibiting both primary tumour growth and dissemination process in a B16BL6 melanoma model. In our study, we show that a single injection of [131I]ICF01012 (ranging from 14.8 to 22.2 MBq) was effective and associated with low and transient haematological toxicity. Concerning pigmented organs, cutaneous melanocytes and skin were undamaged. In 30% of treated animals, no histological alteration of retina was observed, and in the remaining 70%, damages were restricted to the optic nerve area. Using the Medical Internal Radiation Dose methodology, we determined that the absorbed dose in major organs is very low (

International audience; We present the first results obtained with a detector, called Large Area Pixelized Detector (LAPD), dedicated to the study the ballistic control of the beam delivered to the patient by in-beam and real time detection of secondary particles, emitted during its irradiation in the context of hadrontherapy. These particles are 511 keV γ from the annihilation of a positron issued from the β+ emitters induced in the patient tissues along the beam path. The LAPD basic concepts are similar to a conventional PET camera. The 511 keV γ are detected and the reconstructed lines of response allow to measure the β+ activity distribution. Nevertheless, when trying to use γ from positron annihilation for the ballistic control in hadrontherapy, the large prompt γ background should be taken into account and properly rejected. First reconstruction results, obtained with a phantom filled with a high intensity FDG source at the cancer research centre of Clermont-Ferrand are shown. We also report results of measurements performed at the Heidelberg Ion-Beam Therapy Centre with one third of the detector, using proton and carbon ion beams.

La directive 97/43/EURATOM du 30 juin 1997 pointe la radiologie interventionnelle comme une des pratiques speciales (Article 9) susceptibles de delivrer des doses elevees, et pour lesquelles il est demande de veiller a ce que les equipements, les procedures, les programmes d’assurance qualite et la formation des operateurs soient particulierement appropriees. En effet, l’utilisation d’un rayonnement X de faible energie lors de procedures allant de quelques secondes a plusieurs heures pour les examens complexes, renvoie inevitablement a des risques stochastiques et deterministes. L’evaluation de la dose maximum a la peau est donc une donnee appreciable dans l’objectif d’un suivi dermatologique du patient. Dans cette etude nous avons choisi d’utiliser comme detecteur les films radiochromiques XR-RV3-Gafchromic ® afin d’obtenir une cartographie de la dose a la peau recue par le patient lors d’une procedure. Les films radiochromiques sont interessants car ils permettent a la fois de visualiser et de quantifier la region de dose maximale. Nous presentons ici les etapes preliminaires a une utilisation sur patient des films, a savoir l’etude des caracteristiques physiques, l’etalonnage en dose, la lecture par scanner plat et l’exploitation des films avec le logiciel de traitement d’images ImageJ. Les resultats obtenus montrent que l’utilisation des films radiochromiques est pertinente pour une evaluation dosimetrique sur patient. Plus particulierement, la reponse des films differe de moins de 3,6 % entre l’etalonnage a 80 kV et 120 kV et l’incertitude globale reste inferieure a 20 % jusqu’a une dose de 12 Gy. L’evolution de la reponse du film dans le temps etant negligeable, la lecture peut etre faite immediatement et l’exploitation du film necessite moins de 15 minutes pour obtenir la cartographie de la dose. L’application de cette technique de mesure in-vivo pour 58 procedures a permis de mettre en evidence une dose maximale a la peau superieure a 3 Gy pour 12 patients. Ces patients ont alors ete orientes vers un suivi dermatologique. Parmi ces patients, l’evaluation de la dose peau a partir des indicateurs dosimetriques fournis par l’installation aurait mene au suivi de seulement 4 patients.

The GATE Monte Carlo simulation platform based on the GEANT4 toolkit has come into widespread use for simulating positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging devices. Here, we explore its use for calculating electron dose distributions in water. Mono-energetic electron dose point kernels and pencil beam kernels in water are calculated for different energies between 15 keV and 20 MeV by means of GATE 6.0, which makes use of the GEANT4 version 9.2 Standard Electromagnetic Physics Package. The results are compared to the well-validated codes EGSnrc and MCNP4C. It is shown that recent improvements made to the GEANT4/GATE software result in significantly better agreement with the other codes. We furthermore illustrate several issues of general interest to GATE and GEANT4 users who wish to perform accurate simulations involving electrons. Provided that the electron step size is sufficiently restricted, GATE 6.0 and EGSnrc dose point kernels are shown to agree to within less than 3% of the maximum dose between 50 keV and 4 MeV, while pencil beam kernels are found to agree to within less than 4% of the maximum dose between 15 keV and 20 MeV.

La methode de calcul Monte Carlo est reconnue aujourd’hui comme l’algorithme pouvant modeliser au plus pres les phenomenes physiques lies aux depots d’energie dans un milieu. D’ou l’interet d’utiliser cette methode dans la planification de traitement du cancer par rayonnement, les systemes de planification traitement (TPS) existant etant limites dans la precision des calculs pour certains cas bien specifiques. Dans cette approche, nous nous interessons a la validation du code de calcul Monte Carlo GATE pour les applications dosimetriques en physique medicale. Cependant, l’utilisation de la methode Monte Carlo pour des geometries complexes ou des images de haute resolution necessite de nombreuses heures de calculs. En effet, un resultat precis ne peut etre obtenu qu’en generant beaucoup d’evenements. Nous etudions donc les capacites de la grille de calcul de maniere a reduire le temps de calcul en deployant nos simulations avec GATE sur un environnement de calcul distribue.

But Les progres techniques autorisent maintenant les traitements conservateurs des melanomes malins de la choroide. L’evolution de la maladie reste dominee par la crainte de metastases, survenant en moyenne apres trois ans. Le but de ce travail est de rapporter deux cas inhabituels de metastases hepatiques de melanome malin de la choroide survenues 11 et 18 ans apres curietherapie. Materiel et methodes Une femme de 40 ans et un homme de 50 ans ont presente un melanome malin de la choroide du pole posterieur de taille T2 et T3. Ils ont ete traites par disque de cobalt. Dans l’annee qui a suivi, les deux tumeurs ont completement regresse. Les patients ont ete suivis regulierement tous les trois mois pendant cinq ans. Resultats Les metastases hepatiques sont apparues respectivement 11 ans et 18 ans plus tard. Discussion et conclusion Ces deux observations semblent indiquer que la dissemination metastatique etait deja presente au moment du diagnostic et que le temps de doublement cellulaire du melanome uveal etait particulierement long. Elles posent le probleme de la duree du melanome uveal et du depistage infraclinique des metastases.

International audience; The GATE Monte Carlo simulation platform based on the Geant4 toolkit is in constant improvement for dosimetric calculations. In this paper, we present the integration of Geant4-DNA processes into the GATE 7.0 platform in the objective to perform multi-scale simulations (from macroscopic to nanometer scale). We simulated three types of clinical and preclinical beams: a 6 MeV electron clinical beam, a X-ray irradiator beam and a clinical proton beam for which we validated depth dose distributions against measurements in water. Frequencies of energy depositions and DNA damage were evaluated using a specific algorithm in charge of allocating energy depositions to atoms constituting DNA molecules represented by their PDB (Protein Data Bank) description.

Resume Objectif de l'etude Analyse retrospective des resultats de la radiotherapie de l'adenocarcinome non metastatique de la prostate a l'exclusion des complications. Patients et methodes Les 610 cas de stade T1-T2 repertories ont ete traites par irradiation externe dans 19 instituts, entre janvier 1983 et janvier 1988. Le recul moyen etait de 10,4 ans, la moyenne d'âge au debut du traitement de 68,5 ans. Resultats Un controle local a 10 ans a ete obtenu pour 86 % des cancers classes T1-T2 (81,4 % dans le cas des T2). Le taux de rechute metastatique etait a 5 et 10 ans respectivement de 25,3 et 30 % (29 et 38,1 % pour les T2). A 10 ans, 62,4 % des tumeurs de stade T1-T2 n'avaient pas recidive; par ailleurs, le taux de survie globale etait de 45,8 % et celui de survie specifique de 70,5 %; 29,9 % des patients etaient vivants sans signe de recidive. Il y avait une correlation entre le stade (TNM), le grade, le statut ganglionnaire pelvien, le controle tumoral local, la presence d'une obstruction ureterale, et la survie. L'irradiation pelvienne, la dose, l'etalement, le traitement hormonal neoadjuvant et la resection transuretrale n'avaient pas d'influence sur le pronostic. Conclusion Il n'y a pas de difference entre les deux etudes francaises (1975–1982 et 1983–1988) sur le plan du recrutement et du pronostic. Les resultats releves dans la litterature sont voisins des notres. Cette etude souligne l'importance des facteurs de pronostic inherents a la tumeur et au malade.

Beta Irradiation (106Ru/106Rh) versus Gamma Irradiation (125I): A Comparative Study on the Normal Rabbit Eye. We compared beta irradiation (106Ru/106Rh) to gamma irradiation (125I) on the normal rabbit eye, using ophthalmic plaques to deliver doses similar to those recommended in man for choroidal melanoma treatment. A detailed dosimetry was performed and the animals were followed up by clinical and histological examinations during 1 year. The mean total doses were either comparable, or larger with iodine-125, but the globes treated with ruthenium-106 exhibited more damaging effects: total destruction of the chorioretina on the plaque site, abnormalities of the retinal vessels and of the close nerve fiber layers, cavernous atrophy of the optic nerve. In the eyes treated with iodine-125, only the external retinal layers were destroyed.

International audience; The GATE Monte Carlo simulation platform based on the Geant4 toolkit is under constant improvement for dosimetric calculations. In this study, we explore its use for the dosimetry of the preclinical targeted radiotherapy of melanoma using a new specific melanin-targeting radiotracer labeled with iodine 131. Calculated absorbed fractions and S values for spheres and murine models (digital and CT-scan-based mouse phantoms) are compared between GATE and EGSnrc Monte Carlo codes considering monoenergetic electrons and the detailed energy spectrum of iodine 131. The behavior of Geant4 standard and low energy models is also tested. Following the different authors' guidelines concerning the parameterization of electron physics models, this study demonstrates an agreement of 1.2% and 1.5% with EGSnrc, respectively, for the calculation of S values for small spheres and mouse phantoms. S values calculated with GATE are then used to compute the dose distribution in organs of interest using the activity distribution in mouse phantoms. This study gives the dosimetric data required for the translation of the new treatment to the clinic.

Although cancer of the penis is a rare disease, we have collected 506 cases through a multicentric study. In the present study we analyse the results obtained from 259 patients treated by interstitial brachytherapy from 1959 to 1989. Among the 259 patients, 184 males had exclusive brachytherapy (group A) while 75 received a combination of surgery and brachytherapy and/or external beam irradiation (EBI) (group B). Five- and 10-year survival rates are, respectively: overall survival, 66 and 52%; cause-specific survival, 88 and 88%; disease-free survival, 78 and 67%. One hundred and forty-three patients in group A (78%) and 48 (64%) in group B avoided mutilation of the penis while late side effects occurred in 137/259 patients (53%). Survival depends on the volume of the tumor and the presence of involved nodes; systematic groin dissection does not however seem advisable.

Objectifs Depuis le decret du 24 mars 2003, tout acte a visee therapeutique doit faire l’objet d’une etude dosimetrique permettant de definir, au cas par cas, l’exposition des differents organes. En pratique, ce type de calcul dosimetrique reste encore peu applique du fait de sa complexite d’execution. Le calcul de la dose absorbee lors du traitement au 177Lu repose sur la quantification des images realisees a l’111In. Une methodologie semi-automatisee, permettant de corriger les images des principaux biais quantitatifs engendres lors d’acquisitions planaires, a ete developpee afin d’etre applicable dans les delais exiges en routine clinique. L’objectif du present travail est de comparer l’activite calculee par imagerie avec l’activite theorique injectee dans un fantome. Materiels et methodes Une solution radioactive de 1,69 × 10−4 MBq/mL d’111In a ete injectee dans des spheres de 22, 28 et 37 mm de diametre (fantome NEMA). La quantification a ete realisee a partir des donnees scintigraphiques planaires et des volumes segmentes sur TDM. L’activite des spheres a ete calculee apres correction de la diffusion par fenetrage en energie, puis correction de l’attenuation et de l’auto-attenuation a l’aide des coefficients d’attenuation convertis aux energies de l’111In, et enfin par la prise en compte du recouvrement d’organe et du bruit de fond grâce aux volumes segmentes TDM. Ces corrections ont ete implementees sur Image J. L’ecart relatif entre l’activite calculee et theorique de chaque sphere a ete calcule. Nous considerons la methode adaptee lorsque l’ecart est inferieur a 10 %. Resultats Le temps necessaire a la quantification et segmentation des images a ete en moyenne de 30 minutes. Les activites calculees a l’aide des images corrigees ont ete de 1,31 ; 2,10 et 4,55 MBq soit, respectivement, une surestimation de +28,2 ; +9,3 et +1,3 %, respectivement, pour les spheres de 22, 28 et 37 mm. D’apres les criteres definis ci-dessus, la methode de correction est applicable pour les spheres de diametre superieur a 28 mm. L’effet de volume partiel ainsi que les erreurs liees au recalage et a la segmentation semblent expliquer la surestimation de l’activite calculee pour les spheres de diametre inferieure a 28 mm. La duree totale du traitement des images depend essentiellement de la complexite de la segmentation. Conclusions Ces travaux preliminaires ont permis de developper un outil semi-automatique permettant une etude dosimetrique par imagerie planaire scintigraphique. Lorsque l’imagerie 3D n’est pas realisable, la methode 2D proposee represente une alternative applicable et performante en routine clinique.

Objectif Evaluation retrospective monocentrique de l’efficacite de la radiochirurgie par accelerateur lineaire et arctherapie des metastases cerebrales en fonction des differents scores pronostiques. Patients et methodes De mai 1997 a mai 2009, 299 traitements pour des metastases cerebrales chez 181 patients ont ete analyses le cancer primitif etait pour 40 % bronchique non a petites cellules, 18 % renal, 16 % melanique et 26 % d’autre histologie. Les classes RPA ( Recursive Partitioning Analysis ) etaient I, II et III dans 37 %, 59 % et 4 % des cas, le score GPA ( Graded Prognostic Assessment ) etait de 2,5 ou moins et de plus de 2,5 respectivement dans 65 % et 35 %, le score SIR ( Score Index for Radiosurgery ) de 7 ou moins et de plus de 7 dans 58 % et 42 %, le score DS-GPA ( Diagnosis-Specific Graded Pronostic Assessment ) de 3 ou moins et de plus de 3 dans 53 % et 47 %. Les metastases cerebrales ont ete irradiees avec un collimateur micromultilames a une dose mediane de 20 Gy a l’isocentre et 18 Gy en enveloppe. Les indications de radiochirugie etaient apres irradiation panencephalique dans 84 % des cas (44 % pour recidive et 40 % en boost ), et 16 % de novo. Resultats La duree mediane de survie etait de 15 mois en cas de carcinome bronchique, de 9,3 mois en cas de cancer renal, de 8,8 mois en cas de melanome et de 16,7 mois en cas d’autre cancer. Il n’y avait pas de difference significative de survie en fonction des indications de radiochirurgie. La duree mediane de survie pour la classe RPA I etait de 14,5 mois ( p p p p Conclusion Cette etude confirme l’importance des scores pronostiques dans la prise en charge des metastases cerebrales par radiochirurgie.

The GATE Monte Carlo simulation platform based on the Geant4 toolkit has now become a diffused tool for simulating PET and SPECT imaging devices. In this paper, we explore its relevance for dosimetry of low-energy 125I photon brachytherapy sources used to treat prostate cancers. To that end, three 125-iodine sources widely used in prostate cancer brachytherapy treatment have been modelled. GATE simulations reproducing dosimetric reference observables such as radial dose function g(r), anisotropy function F(r, theta) and dose-rate constant (Lambda) were performed in liquid water. The calculations were splitted on the EGEE grid infrastructure to reduce the computing time of the simulations. The results were compared to other relevant Monte Carlo results and to measurements published and fixed as recommended values by the AAPM Task Group 43. GATE results agree with consensus values published by AAPM Task Group 43 with an accuracy better than 2%, demonstrating that GATE is a relevant tool for the study of the dose induced by low-energy photons.

Objectifs L’objectif etait d’evaluer prospectivement les effets doses/volumes de la radiotherapie stereotaxique hypofractionnee pulmonaire. Patients et methodes De 2012 a 2014, 58 nodules pulmonaires, dont 52 % primitifs et 86 % peripheriques (chez 54 patients), ont ete traites par irradiation stereotaxiques sur un accelerateur Novalis Tx® par une technique d’arctherapie dynamique coplanaire. Les doses moyennes prescrites sur l’isodose 80 % etaient de 50,8 Gy (42-54) en trois fractions ou 46,1 Gy (36-60) en cinq fractions. La duree moyenne de suivi etait de 11,3 mois. Les populations recevant le traitement en trois et cinq fractions etaient comparables en termes de volume, d’âge, d’etat general et respiratoire (epreuves fonctionnelles respiratoires et dyspnee). Les volumes tumoraux macroscopiques et cibles previsionnels moyens etaient respectivement de 7,2 cm 3 (0,2–31,4) et 40,2 cm 3 (3,9–131). Resultats Tous nodules confondus, les taux de controle local etaient respectivement 90 % et 77 % a 12 et 24 mois. Les facteurs predictifs etaient un traitement en trois fractions (93 contre 58 % a 24 mois, p = 0,003) et le volume tumoral macroscopique ( p = 0,006). Les probabilites de survie globale des patients atteints de cancer primitifs a 6 et 24 mois etaient respectivement de 89 % et 75 %. Les facteurs pronostiques etaient un traitement en trois fractions (88 contre 43 % a 24 mois, p = 0,01), un volume cible previsionnel plus petit (seuil a 55 cm 3 , p = 0,016) et une dose equivalente biologique (BED) avec un rapport α/β egal a 10 plus forte (seuil a 150 Gy a la moyenne du volume cible previsionnel, p = 0,003). Les taux de pneumopathie de grade 2 selon la Common Terminology Criteria for Adverse Events (CTCAE) a 1, 6 et 12 mois etaient respectivement de 11 %, 24 % et 35 %. Les facteurs predictifs etaient un volume expiratoire maximal par seconde (VEMS) plus bas (46 % si moins de 65 % contre 9,7 % a 12 mois ; p = 0,018), une capacite de diffusion du monoxyde de carbone (DLCO) plus basse (60 % si moins de 37 % contre 16 % a 12 mois ; p = 0,027) et un traitement en trois fractions (44 % contre 14 % a 12 mois, p = 0,024). Les BED ( biological effective dose ) moyennes dans le poumon homolateral etaient plus elevees chez les patients traites en trois fractions (18,2 Gy contre 12,8 Gy, p = 0,017). Conclusion Un VEMS de moins de 5 % et une DLCO de moins de 37 % doivent faire majorer les contraintes pulmonaires, notamment de la dose moyenne dans le poumon homolateral. Une BED moyenne dans le volume cible previsionnel de plus de 150 Gy etait associee a une meilleure probabilite de survie globale dans le cas des cancers primitifs.

Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted simulation toolkit adapted to the field of nuclear medicine. In particular, GATE allows the description of time-dependent phenomena such as source or detector movement, and source decay kinetics. This feature makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms. This paper gives a detailed description of the design and development of GATE by the OpenGATE collaboration, whose continuing objective is to improve, document and validate GATE by simulating commercially available imaging systems for PET and SPECT. Large effort is also invested in the ability and the flexibility to model novel detection systems or systems still under design. A public release of GATE licensed under the GNU Lesser General Public License can be downloaded at http:/www-lphe.epfl.ch/GATE/. Two benchmarks developed for PET and SPECT to test the installation of GATE and to serve as a tutorial for the users are presented. Extensive validation of the GATE simulation platform has been started, comparing simulations and measurements on commercially available acquisition systems. References to those results are listed. The future prospects towards the gridification of GATE and its extension to other domains such as dosimetry are also discussed. ispartof: Physics in medicine and biology vol:49 issue:19 pages:4543-4561 ispartof: location:England status: published

The technical advancements now provide conservative treatment of choroidal melanoma. The course of the disease remains marked by the metastases that usually set in within 3 years. The aim of this paper is to report two unusual cases of hepatic metastases of choroidal melanoma that set in 11 and 18 Years after curietherapy.A 40-year-old woman and a 50-year-old man presented with T2 and T3 choroidal melanomas and were treated by cobalt plaque. The tumors decreased within the year and the patients were monitored every 3 months for 5 years.Metastases set in, respectively, 11 and 18 years after treatment.These two observations show that the metastases had already spread at the moment of diagnosis and that the cell doubling time of the melanoma was very long. These findings indicate the difficulties in monitoring patients with choroidal melanoma.

Monte Carlo simulations are increasingly used in scintigraphic imaging to model imaging systems and to develop and assess tomographic reconstruction algorithms and correction methods for improved image quantitation. GATE (GEANT4 application for tomographic emission) is a new Monte Carlo simulation platform based on GEANT4 dedicated to nuclear imaging applications. This paper describes the GATE simulation of a prototype of scintillation camera dedicated to small-animal imaging and consisting of a CsI(Tl) crystal array coupled to a position-sensitive photomultiplier tube. The relevance of GATE to model the camera prototype was assessed by comparing simulated 99mTc point spread functions, energy spectra, sensitivities, scatter fractions and image of a capillary phantom with the corresponding experimental measurements. Results showed an excellent agreement between simulated and experimental data: experimental spatial resolutions were predicted with an error less than 100 microns. The difference between experimental and simulated system sensitivities for different source-to-collimator distances was within 2%. Simulated and experimental scatter fractions in a [98-182 keV] energy window differed by less than 2% for sources located in water. Simulated and experimental energy spectra agreed very well between 40 and 180 keV. These results demonstrate the ability and flexibility of GATE for simulating original detector designs. The main weakness of GATE concerns the long computation time it requires: this issue is currently under investigation by the GEANT4 and the GATE collaborations.

Treatment of conjunctival epithelial tumors is not standardized because it is difficult to compare large series in this rare disease. Surgical excision is usual, but the recurrence rate has led several authors to propose alternative therapies.During the past 20 years, brachytherapy using ophthalmic applicators has been developed and the results of different studies have confirmed the usefulness of this therapy. We report a retrospective study of 13 patients presenting with a conjunctival epithelial tumor treated with ruthenium106 applicators and followed up in our department since 1987.There was no recurrence during a mean follow-up of 48 months. Complications depended on the size of the area treated and the dose of radiation.

Objectif Evaluation clinique prospective monocentrique des dossiers de patients traites par irradiation stereotaxique pour une tumeur pulmonaire de stade I inoperable ou des metastases a croissance lente avec tumeur primitive controlee. Patients et methodes D’octobre 2012 a fevrier 2014, 29 patients ont recu une radiotherapie stereotaxique thoracique pour 22 nodules primitifs de stade I et 10 metastatiques avec un accelerateur lineaire de type Novalis TX ® . Une acquisition dosimetrique quadridimensionnelle a ete realisee pour les 17 derniers patients. L’âge moyen des patients etait de 66,5 ans (50–84). Huit patients souffraient d’une dyspnee de grade 2 ou plus avant le traitement. Les volumes tumoraux macroscopiques et les volumes cibles previsionnels moyens etaient respectivement 8,3 cm 3 (0,2–31,4 ; mediane = 5,0) et 51 cm 3 (4,0–131,0). La dose variait selon le caractere primitif, secondaire, central ou peripherique du nodule. La dose moyenne delivree etait 62,7 Gy (50–75) a l’isocentre en trois ou cinq fractions avec une dose moyenne par fraction de 17,6 Gy (10–22,5). L’etalement moyen etait de 9,5 jours (3–18). Un suivi clinique et scanographique a ete effectue a 1 mois, puis tous les trois mois. Resultats Le suivi median etait de 7,4 mois. La toxicite selon la classification CTCAE ( Common Terminology Criteria for Adverse Events ) etait de grade 2 ou plus pour 26 patients et de 5 pour deux patients, dont une insuffisance respiratoire aigue 15 jours apres la fin du traitement chez un patient avec un volume expiratoire maximal par seconde (VEMS) de 21 % et une diffusion libre du monoxyde de carbone DLCO) de 14 %. Une reponse objective scanographique a ete observee a 3 mois dans 19 cas (61,3 %), dont neuf avec une diminution superieure a 50 %. A 1 an, les probabilites de survies globale et sans recidive etaient respectivement de 69,4 % et 53,9 % avec un taux de controle local de 85,5 %. Conclusion Les resultats preliminaires de cette etude sur la radiotherapie stereotaxique thoracique sont encourageants. La toxicite respiratoire est a prendre en compte en selectionnant les patients plus rigoureusement. L’evaluation a plus long terme avec plus de patients se poursuit.

We compared beta irradiation (106Ru/106Rh) to gamma irradiation (125I) on the normal rabbit eye, using ophthalmic plaques to deliver doses similar to those recommended in man for choroidal melanoma treatment. A detailed dosimetry was performed and the animals were followed up by clinical and histological examinations during 1 year. The mean total doses were either comparable, or larger with iodine-125, but the globes treated with ruthenium-106 exhibited more damaging effects: total destruction of the chorioretina on the plaque site, abnormalities of the retinal vessels and of the close nerve fiber layers, cavernous atrophy of the optic nerve. In the eyes treated with iodine-125, only the external retinal layers were destroyed.

To analyze 65 patients with uveal melanomas treated with cobalt plaque therapy with regards to mortality, visual results and complications.Most of the melanomas were large (T3: 52.5%), with a mean largest dimension of the base of 11 mm, and a mean thickness of 6 mm. Most of the tumors were located in the choroid (95%), with an anterior margin behind the equator (65%), and a posterior margin at less than 3 mm of the disc and/or of the macula (69%). The plaque radiotherapy delivered a mean dose of 95 Gy to the tumor apex, either with a cobalt plaque alone (51 cases), or in association with a ruthenium plaque (14 cases). The mean follow up period was over 8 years.The local control was achieved initially in 86% of the eyes. The estimated melanoma specific survival rate was 83% after 5 years and 74% after 10 years. The main parameter associated with the metastases was the largest dimension of the base (p0.01). The eye was retained in 83% of the cases. The probability of keeping a vision better than or equal to 0,1 was 39% after 5 years and 27% after 10 years. The main parameter associated with the visual loss was the tumor size (p0.01). The complications included cataract (39%), radiation retinopathy (34%), with maculopathy (19%) and/or papillopathy (13.5%), vitreous hemorrhages (22%), neovascular glaucoma (15%) and retinal detachment (12%).These results supported the value of cobalt plaque radiotherapy in the management of uveal melanomas.

Retrospective analysis of the results of radiotherapy in localized prostatic adenocarcinoma. Complications were excluded.Six-hundred-and-ten T1-T2 adenocarcinomas of the prostate were treated with continuous courses of external beam radiation therapy in 19 participating Institutes between January 1983 and January 1988. The mean follow-up was 10.4 years; the mean age of patients at the beginning of radiotherapy was 68.5 years.A 10-year, local control had been achieved in 86% of T1-T2 (81.4% for T2). The 5- and 10-year metastatic relapse rates were 25.3% and 30% (29% and 38.1% for T2), respectively. At 10 years, 62.4% of T1-T2 were recurrence-free; overall survival rate was 45.8% and cause-specific survival rate was 70.5%; 29.9% of T1-T2 patients were alive and disease-free. T category (TNM), pathologic grade, pelvic lymph node status, local tumor control, and obstructive ureteral symptoms were correlated with survival. The influence of pelvic nodes radiation, dose, overall treatment time, previous endocrine treatment, and transuretral resection was not significant for disease-free survival (alive and disease-free) and other endpoints.There was no difference between the French series (1975-1982 and 1983-1988). The results of the literature are comparable to ours. As far as prognostic factors are concerned, this report provides evidence that the explainable variables which influence survival depend on the tumor and patient status.

Introduction The GATE Monte-Carlo (MC) simulation platform ( www.opengatecollaboration.org ) based on the GEANT4 toolkit has come into widespread use for simulating Positron Emission Tomography, Single Photon Emission Computed Tomography, Computing Tomography (CT) imaging devices and radiation therapy. In this work, we explore the simulation of an intensity-modulated arc therapy (IMAT) treatment using GATE 6.2. To reach this objective, we first performed a complete modeling of the Varian's Novalis Tx linear accelerator (15MV photon mode) using the multileaf collimator (MLC). Then, the simulation of the geometry was validated in water before experiencing a head-and-neck cancer treatment. Material and methods The first stage is to model the Novalis Tx head with the GATE MC platform using manufacturer's data. We simulated this linac in 15 MV mode and compared depth doses, in-plane and cross-plane profiles with reference measurements (performed with ionization chambers (Semiflex 31013, PTW and LA48 Linear Array, PTW) and PTW60012 Diode E) in water for several field sizes ranging from 1 × 1 to 10 × 10 cm 2 . Target and flattening filter geometries and initial electron beamare adjusted in order to fit simulation calculations with dosemeasurements. In a second stage, the MLC geometry implementation enabled the simulation of clinical IMAT treatment plans compared with the iPlan treatment planning software (BrainLab) calculations. In order to reduce the computing time of GATE calculations, the simulations are executed on a distributed infrastructure using the GateLab ( http://vip.creatis.insa-lyon.fr/ ) platform. Results Weshowa good agreement between measurements and simulated depth dose profiles in liquid water. GATE and iPlan normalized treatment plans were compared using agammaindex of ±2%/mm.The ongoing work concerning treatment plan comparisons demonstrates limits of the iPlan Pencil Beam algorithm close to heterogeneities. Using the distributed infrastructure, space phase file was produced in 14 h for 500 million primary photons generated reaching a gain of a factor 50 comparing to calculations performed on a single CPU. Conclusions This study demonstrates that GATE offers efficient tools to make possible IMAT applications. In a subsequent work a microdosimetry study should be performed for a complete validation.

Purpose: In this study, we validate the accuracy of the new GATE 6.0 Monte Carlo platform (using GEANT4 9.2 Standard Electromagnetic Physics Package) to model accurate treatment plans in radiation therapy using 18 MV photon beams. Furthermore, we investigate how the specifications of the particle transport management, physic processes and geometry influence the dosimetric accuracy of the results to propose recommendations on the usage of GATE 6.0. Methods: 3D conformational plans were simulated for a lung irradiation using 18MV photon beams from a Varian Clinac 2100C accelerator. The patient volume was derived from CT images and converted into specific format in order to use different voxel sizes. Treatment plans were computed using GATE 6.0 and EGSnrc. Treatment plans obtained with both of the codes were compared using a gamma index evaluation (acceptance criteria 3%/3mm). Investigations on the influence of simulation parameters related to physics or algorithm were examined by qualitative comparisons of DVHs in several regions of interest: PTV and OARs. Results: At first, GATE 6.0 is able to reproduce complex dosimetry in agreement with the well validated Monte Carlo code EGSnrc. Nevertheless, the choice of specific simulation parameters such as cuts, particle production threshold or stepping algorithm showed differences on treatment plans. Users have to fix parameters according to the geometry simulated to ensure a good tracking of particles by taking into account the computation time efficiency. Conclusions: GATE 6.0 provides convivial tools for realistic treatment planning and give comparable results with EGSnrc while the parameters of the simulation are well fixed. These investigations highlight several issues of general interest to users of GATE 6.0 who wish to calculate accurate treatment plans. We wish to thank the GEANT4 collaboration and the OpenGATE collaboration to their scientific and technical suuport. This work was partly supported by grants from the European Commission (through the EGI inititative project), by the French National Grid Inititative (France Grilles), and regional authorites (Conseil General de l'Allier and Conseil Regional d'Auvergne).

Purpose: By calibratingbrachytherapy (BT) sources to the TG‐43U1 reference position at 1cm in water, named the nominal absorbed dose‐rate to water, Ḋ w ,1, accuracy and precision for patient treatment will be increased. Traceability must be provided to Ḋ w ,1 ‐primary‐standards; which soon become available. Methods and Materials: Efforts have been made in discussions with fellow scientists from many countries, by reviewing concerned literature, and similarities are drawn from documents (e.g. extending TG‐43U1). Results: From the study of primary photon interaction mechanisms, a need was recognized to classify BT‐photon radiation qualities as: high‐energy >100keV, medium energy 40keV to 100keV, and low energy

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Fifty-seven uveal malignant melanomas (T2: 36.8%; T3: 49.1%) were treated between 1983 and 1989 with Cobalt 60 or/and Ruthenium 106 Rhodium 106 plaques. The mean follow-up was 32 months (from 6 to 69 months). A diminution of tumor size was observed in 88% of the cases, either rapid and marked (57%), or slower and more moderate (31%). A multivariate study showed the radiation dose administered to the tumor edge to be the most significant parameter associated with the tumor control. Seven patients developed metastases, and the probability of survival at 60 months was 83.3%. This probability was identical to that of 59 comparable patients treated, some years before, by enucleation. The most frequent complications were radiation retinopathy (28.1%) and retinal detachment (15.8%). The treated eye was retained in 86% of cases. In 57% of treated eyes, vision remained better or equal to 0.1. The predictive parameters of vision impairment after treatment seemed to be tumor size, tumor site near the macula and the optic nerve, and the radiation dose to the tumor base. The use of Ruthenium 106 Rhodium 106 appeared to be advantageous in controlling the disease as well as in reducing the incidence of complications.

The association 106Ru/106Rh and 60Co was used to treat choroidal malignant melanomas with a height of 7 mm above the scleral surface (4 cases) and tumors unsuccessfully treated with a first 60Co plaque therapy (3 cases). The association of both radionuclides allowed a dose of 85 Gy at the apex of the tumor and of 700 Gy at least on the base in every case. All the patients were alive without evidence of metastases with a minimum follow up of one year and the tumor regression was constant and sometimes spectacular.

The dosage of radiations delivered during gynaecological brachytherapy is usually calculated for the bladder and the rectum. A new technical approach is described in order to known the dose of radiation received by the terminal portion of the ureter. During placement of the Fletcher suit one of the ureters is catheterized by a special stent which appears on the X-rays control used for dosimetry. Data of 16 pre-operative brachytherapies for carcinoma of the cervix were studied. In half of the cases, the dose debit was higher on the ureter than on the bladder and the rectum. In 7 cases, the dose delivered was also higher on the ureter rather than on the bladder and the rectum. And in 3 cases this dose was higher than 50 grays. It is concluded that the ureter is frequently the most irradiated organ in the pelvis during brachytherapy for carcinoma of the cervix. This may be a physiopathologic explanation for some ureterovaginal fistulas occurring after radical hysterectomy.