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Sample records for auto-contoured target volume

  1. Integrated-boost IMRT or 3-D-CRT using FET-PET based auto-contoured target volume delineation for glioblastoma multiforme - a dosimetric comparison

    International Nuclear Information System (INIS)

    Biological brain tumor imaging using O-(2-[18F]fluoroethyl)-L-tyrosine (FET)-PET combined with inverse treatment planning for locally restricted dose escalation in patients with glioblastoma multiforme seems to be a promising approach. The aim of this study was to compare inverse with forward treatment planning for an integrated boost dose application in patients suffering from a glioblastoma multiforme, while biological target volumes are based on FET-PET and MRI data sets. In 16 glioblastoma patients an intensity-modulated radiotherapy technique comprising an integrated boost (IB-IMRT) and a 3-dimensional conventional radiotherapy (3D-CRT) technique were generated for dosimetric comparison. FET-PET, MRI and treatment planning CT (P-CT) were co-registrated. The integrated boost volume (PTV1) was auto-contoured using a cut-off tumor-to-brain ratio (TBR) of ≥ 1.6 from FET-PET. PTV2 delineation was MRI-based. The total dose was prescribed to 72 and 60 Gy for PTV1 and PTV2, using daily fractions of 2.4 and 2 Gy. After auto-contouring of PTV1 a marked target shape complexity had an impact on the dosimetric outcome. Patients with 3-4 PTV1 subvolumes vs. a single volume revealed a significant decrease in mean dose (67.7 vs. 70.6 Gy). From convex to complex shaped PTV1 mean doses decreased from 71.3 Gy to 67.7 Gy. The homogeneity and conformity for PTV1 and PTV2 was significantly improved with IB-IMRT. With the use of IB-IMRT the minimum dose within PTV1 (61.1 vs. 57.4 Gy) and PTV2 (51.4 vs. 40.9 Gy) increased significantly, and the mean EUD for PTV2 was improved (59.9 vs. 55.3 Gy, p < 0.01). The EUD for PTV1 was only slightly improved (68.3 vs. 67.3 Gy). The EUD for the brain was equal with both planning techniques. In the presented planning study the integrated boost concept based on inversely planned IB-IMRT is feasible. The FET-PET-based automatically contoured PTV1 can lead to very complex geometric configurations, limiting the achievable mean dose in the boost

  2. Comparison of primary target volumes delineated on four-dimensional CT and 18 F-FDG PET/CT of non-small-cell lung cancer

    International Nuclear Information System (INIS)

    To determine the optimal threshold of 18 F-fluorodexyglucose (18 F-FDG) positron emission tomography CT (PET/CT) images that generates the best volumetric match to internal gross target volume (IGTV) based on four-dimensional CT (4DCT) images. Twenty patients with non-small cell lung cancer (NSCLC) underwent enhanced three-dimensional CT (3DCT) scan followed by enhanced 4DCT scan of the thorax under normal free breathing with the administration of intravenous contrast agents. A total of 100 ml of ioversol was injected intravenously, 2 ml/s for 3DCT and 1 ml/s for 4DCT. Then 18 F-FDG PET/CT scan was performed based on the same positioning parameters (the same immobilization devices and identical position verified by laser localizer as well as skin marks). Gross target volumes (GTVs) of the primary tumor were contoured on the ten phases images of 4DCT to generate IGTV10. GTVPET were determined with eight different threshold using an auto-contouring function. The differences in the position, volume, concordance index (CI) and degree of inclusion (DI) of the targets between GTVPET and IGTV10 were compared. The images from seventeen patients were suitable for further analysis. Significant differences between the centric coordinate positions of GTVPET (excluding GTVPET15%) and IGTV10 were observed only in z axes (P < 0.05). GTVPET15%, GTVPET25% and GTVPET2.0 were not statistically different from IGTV10 (P < 0.05). GTVPET15% approximated closely to IGTV10 with median percentage volume changes of 4.86%. The best CI was between IGTV10 and GTVPET15% (0.57). The best DI of IGTV10 in GTVPET was IGTV10 in GTVPET15% (0.80). None of the PET-based contours had both close spatial and volumetric approximation to the 4DCT IGTV10. At present 3D-PET/CT should not be used for IGTV generation

  3. Irradiation of target volumes with concave outlines

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    De Neve, W.; Fortan, L.; Derycke, S.; Van Duyse, B.; DE Wagter, C. [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde

    1995-12-01

    A heuristic planning procedure allowing to obtain a 3-dimensional conformal dose distribution for target volumes with concavities has been investigated. The procedure divides the planning problem into a number of sub-problems each solvable by known methods. By patching together the solutions to the sub-problems, a solution with a predictable dosimetric outcome can be obtained. The procedure can be applied to most 3-dimensional systems. The procedure is described and its applications to the irradiation of neoplasms are discussed. (A.S.).

  4. Irradiation of target volumes with concave outlines

    International Nuclear Information System (INIS)

    A heuristic planning procedure allowing to obtain a 3-dimensional conformal dose distribution for target volumes with concavities has been investigated. The procedure divides the planning problem into a number of sub-problems each solvable by known methods. By patching together the solutions to the sub-problems, a solution with a predictable dosimetric outcome can be obtained. The procedure can be applied to most 3-dimensional systems. The procedure is described and its applications to the irradiation of neoplasms are discussed. (A.S.)

  5. Target volume definition in radiation oncology

    International Nuclear Information System (INIS)

    The main objective of this book is to provide radiation oncologists with a clear, up-to-date guide to tumor delineation and contouring of organs at risk. With this in mind, a detailed overview of recent advances in imaging for radiation treatment planning is presented. Novel concepts for target volume delineation are explained, taking into account the innovations in imaging technology. Special attention is paid to the role of the newer imaging modalities, such as positron emission tomography and diffusion and perfusion magnetic resonance imaging. All of the most important tumor entities treated with radiation therapy are covered in the book. Each chapter is devoted to a particular tumor type and has been written by a recognized expert in that topic.

  6. Target volume definition in radiation oncology

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    Grosu, Anca-Ligia [Univ. Medical Center Freiburg (Germany). Dept. of Radiation Oncology; Nieder, Carsten (ed.) [Nordland Hospital, Bodo (Norway). Dept. of Oncology

    2015-05-01

    The main objective of this book is to provide radiation oncologists with a clear, up-to-date guide to tumor delineation and contouring of organs at risk. With this in mind, a detailed overview of recent advances in imaging for radiation treatment planning is presented. Novel concepts for target volume delineation are explained, taking into account the innovations in imaging technology. Special attention is paid to the role of the newer imaging modalities, such as positron emission tomography and diffusion and perfusion magnetic resonance imaging. All of the most important tumor entities treated with radiation therapy are covered in the book. Each chapter is devoted to a particular tumor type and has been written by a recognized expert in that topic.

  7. Combined Recipe for Clinical Target Volume and Planning Target Volume Margins

    International Nuclear Information System (INIS)

    Purpose: To develop a combined recipe for clinical target volume (CTV) and planning target volume (PTV) margins. Methods and Materials: A widely accepted PTV margin recipe is Mgeo = aΣgeo + bσgeo, with Σgeo and σgeo standard deviations (SDs) representing systematic and random geometric uncertainties, respectively. On the basis of histopathology data of breast and lung tumors, we suggest describing the distribution of microscopic islets around the gross tumor volume (GTV) by a half-Gaussian with SD Σmicro, yielding as possible CTV margin recipe: Mmicro = ƒ(Ni) × Σmicro, with Ni the average number of microscopic islets per patient. To determine ƒ(Ni), a computer model was developed that simulated radiation therapy of a spherical GTV with isotropic distribution of microscopic disease in a large group of virtual patients. The minimal margin that yielded Dmin <95% in maximally 10% of patients was calculated for various Σmicro and Ni. Because Σmicro is independent of Σgeo, we propose they should be added quadratically, yielding for a combined GTV-to-PTV margin recipe: MGTV-PTV = √([aΣgeo]2 + [ƒ(Ni)Σmicro]2) + bσgeo. This was validated by the computer model through numerous simultaneous simulations of microscopic and geometric uncertainties. Results: The margin factor ƒ(Ni) in a relevant range of Σmicro and Ni can be given by: ƒ(Ni) = 1.4 + 0.8log(Ni). Filling in the other factors found in our simulations (a = 2.1 and b = 0.8) yields for the combined recipe: MGTV-PTV = √((2.1Σgeo)2 + ([1.4 + 0.8log(Ni)] × Σmicro)2) + 0.8σgeo. The average margin difference between the simultaneous simulations and the above recipe was 0.2 ± 0.8 mm (1 SD). Calculating Mgeo and Mmicro separately and adding them linearly overestimated PTVs by on average 5 mm. Margin recipes based on tumor control probability (TCP) instead of Dmin criteria yielded similar results. Conclusions: A general recipe for GTV-to-PTV margins is proposed, which shows that CTV and PTV margins

  8. The effects of target motion in kV-CBCT imaging

    International Nuclear Information System (INIS)

    Background: To study the impact of target motion in kV-CBCT imaging. Material/Methods: To simulate the respiratory movement, dynamic phantom was programmed to move in three dimension with a period of four seconds and of two different amplitudes (PA1 and PA2). The targets of well defined geometries (cylinder, sphere, solid triangle, U-shaped and dumbbell) were made using wax. The static targets were CT imaged (reference image). Using CBCT, the targets in static and dynamic modes were imaged under full-fan beam. The line profiles along cranio-caudal direction, influence of target's initial moving phase and volume estimation using auto-contouring tool were used to analyze the effects of target motion on CBCT imaging. Results: Comparing the line profiles of targets in CBCT with CT, the length of average HU spread was reduced by 42.5 1.85%, except the cylindrical target which is by 19.35% for PA1. The percentage difference in reconstructed volume of static targets imaged using CBCT and CT (HU WW - 500 to 0) ranges from -1.32% to -5.94%. The volume losses for targets imaged in dynamic mode PA1 ranges from 14.35% to 30.95% and for PA2 it was 21.29% to 43.80%. The solid triangle and cylindrical targets suffered the maximum and minimum volume losses respectively. Conclusions: Non-gated CBCT imaging of the moving targets encounters significant loss of volumetric information, due to scatter artifacts. These may result in a systematic error in re-contouring when CBCT images are used for the re-planning work. (authors)

  9. Biological modelling of fuzzy target volumes in 3D radiotherapy

    International Nuclear Information System (INIS)

    Purpose/Objective: The outcome of each radiotherapy depends critically on the optimal choice of the target volume. The goal of the radiotherapist is to include all tumor spread at the same time as saving as much healthy tissue as possible. Even when the information of all imaging modalities is combined, the diagnostic techniques are not sensitive and specific enough to visualize all microscopic tumor cell spread. Due to this lack of information there is room for different interpretations concerning the extend of the target volume, leading to a fuzzy target volume. The aim of this work is to develop a model to score different target volume boundaries within the region of diagnostic uncertainty in terms of tumor control probability (TCP) and normal tissue complication probabilities (NTCP). Materials and Methods: In order to assess the region of diagnostic uncertainty, the radiotherapist defines interactively a minimal planning target volume that absolutely must be irradiated according to the diagnostic information available and a maximal planning target volume outside which no tumor cell spread is expected. For the NTCP calculation we use the Lyman 4 parameter model to estimate the response of an organ at risk to a uniform partial volume irradiation. The TCP calculation is based on the Poisson model of cell killing. The TCP estimation depends not only on volume, dose, clonogenic cell density and the α parameter of the linear quadratic model but also on the probability to find clonogenic cells in the considered volume. Inside the minimal PTV this probability is 1, outside the maximal PTV it is 0. Therefore all voxels inside the minimal PTV are assigned the value of 1 with respect to the target volume, all voxels outside the maximal PTV the value of 0. For voxels in the region of uncertainty in between, a 3D linear interpolation is performed. Here we assume the probability to follow the interpolated values. Starting with the minimal PTV, the expected gain in TCP and

  10. Target volumes in radiation therapy of childhood brain tumours

    International Nuclear Information System (INIS)

    Pediatric tumors have enjoyed considerable improvements for the past 30 years. This is mainly due to the extensive use of combined therapeutical modalities in which chemotherapy plays a prominent role. In many children, local treatment including radiotherapy, can nowadays be adapted in terms of target volume and dose to the 'response' to an initial course of chemotherapy almost on a case by case basis. This makes precise recommendation on local therapy highly difficult in this age group. We will concentrate in this paper on brain tumors in which chemotherapy is of limited value and radiotherapy still plays a key-role. (authors)

  11. Diffusion tensor imaging for target volume definition in glioblastoma multiforme

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    Berberat, Jatta; Remonda, Luca [Cantonal Hospital, Department of Neuro-radiology, Aarau (Switzerland); McNamara, Jane; Rogers, Susanne [Cantonal Hospital, Department of Radiation Oncology, Aarau (Switzerland); Bodis, Stephan [Cantonal Hospital, Department of Radiation Oncology, Aarau (Switzerland); University Hospital, Department of Radiation Oncology, Zurich (Switzerland)

    2014-10-15

    Diffusion tensor imaging (DTI) is an MR-based technique that may better detect the peritumoural region than MRI. Our aim was to explore the feasibility of using DTI for target volume delineation in glioblastoma patients. MR tensor tracts and maps of the isotropic (p) and anisotropic (q) components of water diffusion were coregistered with CT in 13 glioblastoma patients. An in-house image processing program was used to analyse water diffusion in each voxel of interest in the region of the tumour. Tumour infiltration was mapped according to validated criteria and contralateral normal brain was used as an internal control. A clinical target volume (CTV) was generated based on the T{sub 1}-weighted image obtained using contrast agent (T{sub 1Gd}), tractography and the infiltration map. This was compared to a conventional T{sub 2}-weighted CTV (T{sub 2}-w CTV). Definition of a diffusion-based CTV that included the adjacent white matter tracts proved highly feasible. A statistically significant difference was detected between the DTI-CTV and T{sub 2}-w CTV volumes (p < 0.005, t = 3.480). As the DTI-CTVs were smaller than the T{sub 2}-w CTVs (tumour plus peritumoural oedema), the pq maps were not simply detecting oedema. Compared to the clinical planning target volume (PTV), the DTI-PTV showed a trend towards volume reduction. These diffusion-based volumes were smaller than conventional volumes, yet still included sites of tumour recurrence. Extending the CTV along the abnormal tensor tracts in order to preserve coverage of the likely routes of dissemination, whilst sparing uninvolved brain, is a rational approach to individualising radiotherapy planning for glioblastoma patients. (orig.) [German] Die Diffusions-Tensor-Bildgebung (DTI) ist eine MR-Technik, die dank der Erfassung des peritumoralen Bereichs eine Verbesserung bezueglich MRI bringt. Unser Ziel war die Pruefung der Machbarkeit der Verwendung der DTI fuer die Zielvolumenabgrenzung fuer Patienten mit

  12. Target volume uncertainty and a method to visualize its effect on the target dose prescription

    International Nuclear Information System (INIS)

    Purpose: To consider the uncertainty in the construction of target boundaries for optimization, and to demonstrate how the principles of mathematical programming can be applied to determine and display the effect on the tumor dose of making small changes to the target boundary. Methods: The effect on the achievable target dose of making successive small shifts to the target boundary within its range of uncertainty was found by constructing a mixed-integer linear program that automated the placement of the beam angles using the initial target volume. Results: The method was demonstrated using contours taken from a nasopharynx case, with dose limits placed on surrounding structures. In the illustrated case, enlarging the target anteriorly to provide greater assurance of disease coverage did not force a sacrifice in the minimum or mean tumor doses. However, enlarging the margin posteriorly, near a critical structure, dramatically changed the minimum, mean, and maximum tumor doses. Conclusion: Tradeoffs between the position of the target boundary and the minimum target dose can be developed using mixed-integer programming, and the results projected as a guide to contouring and plan selection

  13. [Gross tumor volume (GTV) and clinical target volume (CTV) in radiotherapy of benign skull base tumors].

    Science.gov (United States)

    Maire, J P; Liguoro, D; San Galli, F

    2001-10-01

    Skull base tumours represent about 35 to 40% of all intracranial tumours. There are now many reports in the literature confirming the fact that about 80 to 90% of such tumours are controlled with fractionated radiotherapy. Stereotactic and 3-dimensional treatment planning techniques increase local control and central nervous system tolerance. Definition of the gross tumor volume (GTV) is generally easy with currently available medical imaging systems and computers for 3-dimensional dosimetry. The definition of the clinical target volume (CTV) is more difficult to appreciate; it is defined from the CTV plus a margin, which depends on the histology and anterior therapeutic history of the tumour. It is important to take into account the visible tumour and its possible extension pathways (adjacent bone, holes at the base of skull) and/or an anatomic region (sella turcica + adjacent cavernous sinus). It is necessary to evaluate these volumes with CT Scan and MRI to appreciate tumor extension in a 3-dimentional approach, in order to reduce the risk of marginal recurrences. The aim of this paper is to discuss volume definition as a function of tumour site and tumour type to be irradiated. PMID:11715310

  14. 11C-methane production in small volume, high pressure gas targets

    International Nuclear Information System (INIS)

    The parameters affecting the production of 11C-methane, in situ, in small volume, high-pressure gas targets include target chamber size and material. The results are based on experiments that varied the target gas composition, the target material and geometry. Methane production yields were typically 65% of the yields of 11CO2 in the same target chamber. (orig.)

  15. [Gross tumor volume (GTV) and clinical target volume (CTV) in adult gliomas].

    Science.gov (United States)

    Kantor, G; Loiseau, H; Vital, A; Mazeron, J J

    2001-10-01

    Glioblastoma multiform and astrocytoma are the most frequent primary cancer of the central nervous system of adult. Definitions of gross tumor volume (GTV) and clinical target volume (CTV) are based on the confrontation of clinical presentation (age, performance status, neurologic symptoms...), histological type and imaging aspects. For glioblastoma multiform, the GTV can be defined by the area of contrast enhancement observed on the CT scan or MRI. Definition of the CTV can be more difficult and have to take into account the risk of presence of isolated malignant cells in the oedema surrounding the tumor or in the adjacent brain structures. The classical concept of GTV plus a safety margin of 2 cm around is discussed with a CTV containing at least all the oedematous area and eventually adjacent brain structures (nuclei, corpus callosum or other long associative fibers...). For low grade astrocytoma, the definition of GTV can be difficult if the tumoral infiltration is diffuse without nodular visible tumor. CTV corresponds to at least T2 MRI hypersignal area when visible. For postoperative tumor, technical considerations are important for the detection of residual tumor. A safety margin around the resected area is designed according to the risk of presence of isolated cells or involvement of adjacent brain structures. PMID:11715309

  16. Improving the consistency in cervical esophageal target volume definition by special training

    International Nuclear Information System (INIS)

    Purpose: Three-dimensional conformal radiation therapy requires the precise definition of the target volume. Its potential benefits could be offset by the inconsistency in target definition by radiation oncologists. In a previous survey of radiation oncologists, a large degree of variation in target volume definition of cervical esophageal cancer was noted for the boost phase of radiotherapy. The present study evaluated whether special training could improve the consistency in target volume definitions. Methods and Materials: A pre-training survey was performed to establish baseline values. This was followed by a special one-on-one training session on treatment planning based on the RTOG 94-05 protocol to 12 radiation oncologists. Target volumes were redrawn immediately and at 1-2 months later. Post-training vs. pre-training target volumes were compared. Results: There was less variability in the longitudinal positions of the target volumes post-training compared to pre-training (p<0.05 in 5 of 6 comparisons). One case had more variability due to the lack of a visible gross tumor on CT scans. Transverse contours of target volumes did not show any significant difference pre- or post-training. Conclusion: For cervical esophageal cancer, this study suggests that special training on protocol guidelines may improve consistency in target volume definition. Explicit protocol directions are required for situations where the gross tumor is not easily visible on CT scans. This may be particularly important for multicenter clinical trials, to reduce the occurrences of protocol violations

  17. Target volume delineation variation in radiotherapy for early stage rectal cancer in the Netherlands

    NARCIS (Netherlands)

    Nijkamp, Jasper; de Haas-Kock, Danielle F. M.; Beukema, Jannet C.; Neelis, Karen J.; Woutersen, Dankert; Ceha, Heleen; Rozema, Tom; Slot, Annerie; Vos-Westerman, Hanneke; Intven, Martijn; Spruit, Patty H.; van der Linden, Yvette; Geijsen, Debby; Verschueren, Karijn; van Herk, Marcel B.; Marijnen, Corrie A. M.

    2012-01-01

    Purpose: The aim of this study was to measure and improve the quality of target volume delineation by means of national consensus on target volume definition in early-stage rectal cancer. Methods and materials: The CTV's for eight patients were delineated by 11 radiation oncologists in 10 institutes

  18. Technology transfer from NASA to targeted industries, volume 2

    Science.gov (United States)

    Mccain, Wayne; Schroer, Bernard J.; Souder, William E.; Spann, Mary S.; Watters, Harry; Ziemke, M. Carl

    1993-01-01

    This volume contains the following materials to support Volume 1: (1) Survey of Metal Fabrication Industry in Alabama; (2) Survey of Electronics Manufacturing/Assembly Industry in Alabama; (3) Apparel Modular Manufacturing Simulators; (4) Synopsis of a Stereolithography Project; (5) Transferring Modular Manufacturing Technology to an Apparel Firm; (6) Letters of Support; (7) Fact Sheets; (8) Publications; and (9) One Stop Access to NASA Technology Brochure.

  19. Delineation of Supraclavicular Target Volumes in Breast Cancer Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Lindsay C. [Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota (United States); Diehn, Felix E. [Department of Radiology, Mayo Clinic, Rochester, Minnesota (United States); Boughey, Judy C. [Department of Surgery, Mayo Clinic, Rochester, Minnesota (United States); Childs, Stephanie K.; Park, Sean S.; Yan, Elizabeth S.; Petersen, Ivy A. [Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota (United States); Mutter, Robert W., E-mail: mutter.robert@mayo.edu [Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota (United States)

    2015-07-01

    Purpose: To map the location of gross supraclavicular metastases in patients with breast cancer, in order to determine areas at highest risk of harboring subclinical disease. Methods and Materials: Patients with axial imaging of gross supraclavicular disease were identified from an institutional breast cancer registry. Locations of the metastatic lymph nodes were transferred onto representative axial computed tomography images of the supraclavicular region and compared with the Radiation Therapy Oncology Group (RTOG) breast cancer atlas for radiation therapy planning. Results: Sixty-two patients with 161 supraclavicular nodal metastases were eligible for study inclusion. At the time of diagnosis, 117 nodal metastases were present in 44 patients. Forty-four nodal metastases in 18 patients were detected at disease recurrence, 4 of whom had received prior radiation to the supraclavicular fossa. Of the 161 nodal metastases, 95 (59%) were within the RTOG consensus volume, 4 nodal metastases (2%) in 3 patients were marginally within the volume, and 62 nodal metastases (39%) in 30 patients were outside the volume. Supraclavicular disease outside the RTOG consensus volume was located in 3 regions: at the level of the cricoid and thyroid cartilage (superior to the RTOG volume), in the posterolateral supraclavicular fossa (posterolateral to the RTOG volume), and in the lateral low supraclavicular fossa (lateral to the RTOG volume). Only women with multiple supraclavicular metastases had nodal disease that extended superiorly to the level of the thyroid cartilage. Conclusions: For women with risk of harboring subclinical supraclavicular disease warranting the addition of supraclavicular radiation, coverage of the posterior triangle and the lateral low supraclavicular region should be considered. For women with known supraclavicular disease, extension of neck coverage superior to the cricoid cartilage may be warranted.

  20. Delineation of Supraclavicular Target Volumes in Breast Cancer Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: To map the location of gross supraclavicular metastases in patients with breast cancer, in order to determine areas at highest risk of harboring subclinical disease. Methods and Materials: Patients with axial imaging of gross supraclavicular disease were identified from an institutional breast cancer registry. Locations of the metastatic lymph nodes were transferred onto representative axial computed tomography images of the supraclavicular region and compared with the Radiation Therapy Oncology Group (RTOG) breast cancer atlas for radiation therapy planning. Results: Sixty-two patients with 161 supraclavicular nodal metastases were eligible for study inclusion. At the time of diagnosis, 117 nodal metastases were present in 44 patients. Forty-four nodal metastases in 18 patients were detected at disease recurrence, 4 of whom had received prior radiation to the supraclavicular fossa. Of the 161 nodal metastases, 95 (59%) were within the RTOG consensus volume, 4 nodal metastases (2%) in 3 patients were marginally within the volume, and 62 nodal metastases (39%) in 30 patients were outside the volume. Supraclavicular disease outside the RTOG consensus volume was located in 3 regions: at the level of the cricoid and thyroid cartilage (superior to the RTOG volume), in the posterolateral supraclavicular fossa (posterolateral to the RTOG volume), and in the lateral low supraclavicular fossa (lateral to the RTOG volume). Only women with multiple supraclavicular metastases had nodal disease that extended superiorly to the level of the thyroid cartilage. Conclusions: For women with risk of harboring subclinical supraclavicular disease warranting the addition of supraclavicular radiation, coverage of the posterior triangle and the lateral low supraclavicular region should be considered. For women with known supraclavicular disease, extension of neck coverage superior to the cricoid cartilage may be warranted

  1. MRI definition of target volumes using fuzzy logic method for three-dimensional conformal radiation therapy

    International Nuclear Information System (INIS)

    Purpose: Three-dimensional (3D) volume determination is one of the most important problems in conformal radiation therapy. Techniques of volume determination from tomographic medical imaging are usually based on two-dimensional (2D) contour definition with the result dependent on the segmentation method used, as well as on the user's manual procedure. The goal of this work is to describe and evaluate a new method that reduces the inaccuracies generally observed in the 2D contour definition and 3D volume reconstruction process. Methods and Materials: This new method has been developed by integrating the fuzziness in the 3D volume definition. It first defines semiautomatically a minimal 2D contour on each slice that definitely contains the volume and a maximal 2D contour that definitely does not contain the volume. The fuzziness region in between is processed using possibility functions in possibility theory. A volume of voxels, including the membership degree to the target volume, is then created on each slice axis, taking into account the slice position and slice profile. A resulting fuzzy volume is obtained after data fusion between multiorientation slices. Different studies have been designed to evaluate and compare this new method of target volume reconstruction and a classical reconstruction method. First, target definition accuracy and robustness were studied on phantom targets. Second, intra- and interobserver variations were studied on radiosurgery clinical cases. Results: The absolute volume errors are less than or equal to 1.5% for phantom volumes calculated by the fuzzy logic method, whereas the values obtained with the classical method are much larger than the actual volumes (absolute volume errors up to 72%). With increasing MRI slice thickness (1 mm to 8 mm), the phantom volumes calculated by the classical method are increasing exponentially with a maximum absolute error up to 300%. In contrast, the absolute volume errors are less than 12% for phantom

  2. Volume rendering in treatment planning for moving targets

    International Nuclear Information System (INIS)

    Advances in computer technologies have facilitated the development of tools for 3-dimensional visualization of CT-data sets with volume rendering. The company Fovia has introduced a high definition volume rendering engine (HDVR trademark by Fovia Inc., Palo Alto, USA) that is capable of representing large CT data sets with high user interactivity even on standard PCs. Fovia provides a software development kit (SDK) that offers control of all the features of the rendering engine. We extended the SDK by functionalities specific to the task of treatment planning for moving tumors. This included navigation of the patient's anatomy in beam's eye view, fast point-and-click measurement of lung tumor trajectories as well as estimation of range perturbations due to motion by calculation of (differential) water equivalent path lengths for protons and carbon ions on 4D-CT data sets. We present patient examples to demonstrate the advantages and disadvantages of volume rendered images as compared to standard 2-dimensional axial plane images. Furthermore, we show an example of a range perturbation analysis. We conclude that volume rendering is a powerful technique for the representation and analysis of large time resolved data sets in treatment planning

  3. Target volume definition for three-dimensional conformal radiation therapy of lung cancer.

    Science.gov (United States)

    Armstrong, J G

    1998-06-01

    Three-dimensional conformal radiation therapy (3DCRT) is a mode of high precision radiotherapy which has the potential to improve the therapeutic ratio of radiation therapy for locally advanced non-small cell lung cancer. The preliminary clinical experience with 3DCRT has been promising and justifies further endeavour to refine its clinical application and ultimately test its role in randomized trials. There are several steps to be taken before 3DCRT evolves into an effective single modality for the treatment of lung cancer and before it is effectively integrated with chemotherapy. This article addresses core issues in the process of target volume definition for the application of 3DCRT technology to lung cancer. The International Commission on Radiation Units and Measurements Report no. 50 definitions of target volumes are used to identify the factors influencing target volumes in lung cancer. The rationale for applying 3DCRT to lung cancer is based on the frequency of failure to eradicate gross tumour with conventional approaches. It may therefore be appropriate to ignore subclinical or microscopic extensions when designing a clinical target volume, thereby restricting target volume size and allowing dose escalation. When the clinical target volume is expanded to a planning target volume, an optimized margin would result in homogeneous irradiation to the highest dose feasible within normal tissue constraints. To arrive at such optimized margins, multiple factors, including data acquisition, data transfer, patient movement, treatment reproducibility, and internal organ and target volume motion, must be considered. These factors may vary significantly depending on technology and techniques, and published quantitative analyses are no substitute for meticulous attention to detail and audit of performance. PMID:9849380

  4. International Spine Radiosurgery Consortium Consensus Guidelines for Target Volume Definition in Spinal Stereotactic Radiosurgery

    International Nuclear Information System (INIS)

    Purpose: Spinal stereotactic radiosurgery (SRS) is increasingly used to manage spinal metastases. However, target volume definition varies considerably and no consensus target volume guidelines exist. This study proposes consensus target volume definitions using common scenarios in metastatic spine radiosurgery. Methods and Materials: Seven radiation oncologists and 3 neurological surgeons with spinal radiosurgery expertise independently contoured target and critical normal structures for 10 cases representing common scenarios in metastatic spine radiosurgery. Each set of volumes was imported into the Computational Environment for Radiotherapy Research. Quantitative analysis was performed using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE) with kappa statistics calculating agreement between physicians. Optimized confidence level consensus contours were identified using histogram agreement analysis and characterized to create target volume definition guidelines. Results: Mean STAPLE agreement sensitivity and specificity was 0.76 (range, 0.67-0.84) and 0.97 (range, 0.94-0.99), respectively, for gross tumor volume (GTV) and 0.79 (range, 0.66-0.91) and 0.96 (range, 0.92-0.98), respectively, for clinical target volume (CTV). Mean kappa agreement was 0.65 (range, 0.54-0.79) for GTV and 0.64 (range, 0.54-0.82) for CTV (P<.01 for GTV and CTV in all cases). STAPLE histogram agreement analysis identified optimal consensus contours (80% confidence limit). Consensus recommendations include that the CTV should include abnormal marrow signal suspicious for microscopic invasion and an adjacent normal bony expansion to account for subclinical tumor spread in the marrow space. No epidural CTV expansion is recommended without epidural disease, and circumferential CTVs encircling the cord should be used only when the vertebral body, bilateral pedicles/lamina, and spinous process are all involved or there is extensive metastatic

  5. Repeated CT scan in improving the reproducibility of grass tumor volume for moving target

    International Nuclear Information System (INIS)

    Objective: To find a method to improve the range accuracy of moving target such as peripheral lung tumors, since a single CT snapshot may not be accurate during the treatment process.Methods: A simple harmonic motion phantom, embedded with a cube and a circular ball, was used to simulate the tumor motion. Individualized moving targets were scanned 24 times with different amplitudes and frequencies. Then the images were fused from every 1, 2 or 3 sets of CT scans. The GTV volume variation of circular target and the length variation of the cube target along the z axis were contoured and analyzed. Results: As motion amplitude increased, the maximum of both circular target volume and cube target length was increased, while the minimum of the factors was decreased. Motion frequency affected the target volume less than amplitude. For a cube target with the length of 3.3 cm at stationary phase, when motion frequencies was 20 and motion amplitude was 2 cm, the maximal length was 2. 4 times of the minimal length (5. 1 cm vs. 2. 1 cm). When it came to the cube target groups fused from every 1,2 and 3 sets of CT scans, the average length and standard deviation were (3.77 ± 1.20)cm, (4.18 ±0. 91)cm and (4.52 ±0. 59)cm, respectively. With the increase of fused scan number, targets became bigger, the standard deviation decreased, and the change of center positions was decreased. Conclusions: The motion amplitude, frequency and the number of CT scans are the main factors affecting target definition, though, the optimized scanning phase is not certained. When 4DCT and respiration gating technique are not available,the efficient and practical method to solve this problem is to scan the target three or more times and fuse them in planning system, which will generate a larger, more reproducible GTV volume for moving targets. (authors)

  6. Rectal cancer: The radiation basis of radiotherapy, target volume; Cancers du rectum: volumes cible de la radiotherapie, bases rationnelles

    Energy Technology Data Exchange (ETDEWEB)

    Bosset, J.F.; Servagi-Vernat, S. [Service oncologie-radiotherapie, CHU Jean-Minjoz, 3, boulevard Fleming, 25030 Besancon (France); Crehange, G. [Service oncologie-radiotherapie, centre Georges-Francois-Leclerc, 1, rue du Pr-Marion, 21079 Dijon cedex (France); Azria, D. [Service oncologie-radiotherapie, centre Val-d' Aurelle, rue Croix-Verte, 34298 Montpellier cedex 5 (France); Gerard, J.P. [Service oncologie-radiotherapie, centre Antoine-Lacassagne, 33, avenue Valombrose, 06189 Nice (France); Hennequin, C. [Service oncologie-radiotherapie, hopital Saint-Louis, 1, avenue Claude-Vellefaux, 75475 Paris (France)

    2011-10-15

    Since the implementation of preoperative chemo-radiotherapy and meso-rectal excision, the 5-year rates of locoregional failures in T3-T4 N0-N1M0 rectal cancer fell from 25-30% thirty years ago to 5-8% nowadays. A critical analysis of the locoregional failures sites and mechanisms, as well as the identification of nodal extension, helps the radiation oncologist to optimize the radiotherapy target definition. The upper limit of the clinical target volume is usually set at the top of the third sacral vertebra. The lateral pelvic nodes should be included when the tumor is located in the distal part of the rectum. The anal sphincter and the levator muscles should be spared when a conservative surgery is planned. In case of abdomino-perineal excision, the ischio-rectal fossa and the sphincters should be included in the clinical target volume. A confrontation with radiologist and surgeon is mandatory to improve the definition of the target volumes to be treated. (authors)

  7. Organs at risk and target volumes: Definition for conformal radiation therapy in breast cancer

    International Nuclear Information System (INIS)

    Adjuvant radiotherapy is a standard component of breast cancer treatment. The addition of radiotherapy after breast conserving surgery has been shown to reduce local recurrence rate and improve long-term survival. Accurate delineation of target volumes and organs at risk is crucial to the quality of treatment planning and delivered accomplished with innovate technologies in radiation therapy. This allows the radiation beam to be shaped specifically to each individual patient's anatomy. Target volumes include the mammary gland and surgical bed in case of breast conserving surgery, the chest wall in case of mastectomy, and if indicated, regional lymph nodes (axillary, supra- and infra-clavicular and internal mammary). Organs at risk include lungs, thyroid, brachial plexus, heart, spinal cord and oesophagus. The aim of this article is to encourage the use of conformal treatment and delineation of target volumes and organs at risk and to describe specifically the definition of these volumes. (authors)

  8. Optimized training of responsible shift personnel in nuclear power plants. Supplement volume 5 for chapter 7: Learning targets

    International Nuclear Information System (INIS)

    This supplement volume describes the process to establish learning targets in the administrative and organizational sectors, the method adopted in revising learning targets, as well as learning targets to be attained by studying publications of other institutions. (DG)

  9. Microinvasion of liver metastases from colorectal cancer: predictive factors and application for determining clinical target volume

    OpenAIRE

    Qian, Yang; Zeng, Zhao-Chong; Ji, Yuan; Xiao, Yin-Ping

    2015-01-01

    Objectives This study evaluates the microscopic characteristics of liver metastases from colorectal cancer (LMCRC) invasion and provides a reference for expansion from gross tumor volume (GTV) to clinical targeting volume (CTV). Methods Data from 129 LMCRC patients treated by surgical resection at our hospital between January 2008 and September 2009 were collected for study. Tissue sections used for pathology and clinical data were reviewed. Patient information used for the study included gen...

  10. Magnetic Resonance Imaging- Versus Computed Tomography-Based Target Volume Delineation of the Glandular Breast Tissue (Clinical Target Volume Breast) in Breast-Conserving Therapy: An Exploratory Study

    International Nuclear Information System (INIS)

    Purpose: To examine MRI and CT for glandular breast tissue (GBT) volume delineation and to assess interobserver variability. Methods and Materials: Fifteen breast cancer patients underwent a planning CT and MRI, consecutively, in the treatment position. Four observers (two radiation oncologists and two radiologists) delineated the GBT according to the CT and separately to the MR images. Volumes, centers of mass, maximum extensions with standard deviations (SD), and interobserver variability were quantified. Observers viewed delineation differences between MRI and CT and delineation differences among observers. Results: In cranio-lateral and cranio-medial directions, GBT volumes were delineated larger using MRI when compared with those delineated with CT. Center of mass on MRI shifted a mean (SD) 17% (4%) into the cranial direction and a mean 3% (4%) into the dorsal direction when compared with that on the planning CT. Only small variations between observers were noted. The GBT volumes were approximately 4% larger on MRI (mean [SD] ratio MRI to CT GBT volumes, 1.04 [0.06]). Findings were concordant with viewed MRI and CT images and contours. Conformity indices were only slightly different; mean conformity index was 77% (3%) for MRI and 79% (4%) for CT. Delineation differences arising from personal preferences remained recognizable irrespective of the imaging modality used. Conclusions: Contoured GBT extends substantially further into the cranio-lateral and cranio-medial directions on MRI when compared with CT. Interobserver variability is comparable for both imaging modalities. Observers should be aware of existing personal delineation preferences. Institutions are recommended to review and discuss target volume delineations and to design supplementary guidelines if necessary.

  11. Comparison between CT- and FDG-PET-defined target volumes for radiotherapy planning in head-and-neck cancers

    International Nuclear Information System (INIS)

    Nine patients with head-and-neck cancer underwent computerized tomography (CT) simulation and [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) to compare the radiotherapy target volumes. The PET volumes were delineated with an automatic segmentation based on the source-to-background ratio. The volume comparison showed a reduction and qualitative discrepancies between the PET- and CT-volumes.

  12. Analysis of target volumes for gliomas; Volumes-cibles anatomocliniques (GTV et CTV) des tumeurs gliales

    Energy Technology Data Exchange (ETDEWEB)

    Kantor, G. [Centre Regional de Lutte Contre le Cancer, Service de Radiotherapie, Institut Bergonie, 33 - Bordeaux (France); Bordeaux-2 Univ., 33 (France); Loiseau, H. [Hopital Pellegrin-Tripode, Service de Neurochirurgie, 33 - Bordeaux (France); Bordeaux-2 Univ., 33 (France)

    2005-06-15

    Gliomas are the most frequent tumors of the central nervous system of the adult. These intra-parenchymal tumors are infiltrative and the most important criterion for definition of GTV and CTV is the extent of infiltration. Delineation of GTV and CTV for untreated and resected glioma remains a controversial and difficult issue because of the discrepancy between real tumor invasion and that estimated by CT or MRI. Is particularly helpful a joint analysis of the four different methods as histopathological correlations with CT and MRI, use of new modality imaging, pattern of relapses after treatment and interobserver studies. The presence of isolated tumor cells in intact brain, oedema or adjacent structures requires the definition of two different options for CTV: i) a geometrical option with GTV defined as the tumor mass revealed by the contrast-enhanced zone on CT or MRI and a CTV with an expanded margin of 2 or 3 cm; ii) an anatomic option including the entire zone of oedema or isolated tumor cell infiltration extending at least as far as the limits of the hyperintense zone on T2-weighted MRI. Inclusion of adjacent structures (such as white matter, corpus callosum, subarachnoid spaces) in the CTV mainly depends on the site of the tumor and size of the volume is generally enlarged. (authors)

  13. Target volume delineation variation in radiotherapy for early stage rectal cancer in the Netherlands

    International Nuclear Information System (INIS)

    Purpose: The aim of this study was to measure and improve the quality of target volume delineation by means of national consensus on target volume definition in early-stage rectal cancer. Methods and materials: The CTV’s for eight patients were delineated by 11 radiation oncologists in 10 institutes according to local guidelines (phase 1). After observer variation analysis a workshop was organized to establish delineation guidelines and a digital atlas, with which the same observers re-delineated the dataset (phase 2). Variation in volume, most caudal and cranial slice and local surface distance variation were analyzed. Results: The average delineated CTV volume decreased from 620 to 460 cc (p < 0.001) in phase 2. Variation in the caudal CTV border was reduced significantly from 1.8 to 1.2 cm SD (p = 0.01), while it remained 0.7 cm SD for the cranial border. The local surface distance variation (cm SD) reduced from 1.02 to 0.74 for anterior, 0.63 to 0.54 for lateral, 0.33 to 0.25 for posterior and 1.22 to 0.46 for the sphincter region, respectively. Conclusions: The large variation in target volume delineation could significantly be reduced by use of consensus guidelines and a digital delineation atlas. Despite the significant reduction there is still a need for further improvement.

  14. Contrast enhanced 4D-CT imaging for target volume definition in pancreatic ductal adenocarcinoma

    International Nuclear Information System (INIS)

    A procedure to improve target volume definition in pancreatic ductal adenocarcinoma by contrast enhanced 4D-CT imaging has been implemented for radiotherapy planning. The procedure allows good quality images to be obtained over the whole patient's breathing cycle in terms of anatomical details, pancreatic enhancement and vessel definition

  15. ESTRO consensus guideline on target volume delineation for elective radiation therapy of early stage breast cancer

    NARCIS (Netherlands)

    Offersen, B.V.; Boersma, L.J.; Kirkove, C.; Hol, S.; Aznar, M.C.; Sola, A. Biete; Kirova, Y.M.; Pignol, J.P.; Remouchamps, V.; Verhoeven, K.; Weltens, C.; Arenas, M.; Gabrys, D.; Kopek, N.; Krause, M.; Lundstedt, D.; Marinko, T.; Montero, A.; Yarnold, J.; Poortmans, P.M.P.

    2015-01-01

    BACKGROUND AND PURPOSE: Delineation of clinical target volumes (CTVs) is a weak link in radiation therapy (RT), and large inter-observer variation is seen in breast cancer patients. Several guidelines have been proposed, but most result in larger CTVs than based on conventional simulator-based RT. T

  16. Investigations on the necessity of dose calculations for several planes of the target volume

    International Nuclear Information System (INIS)

    In radiotherapy planning, the shape of a target volume can at present be exactly delimited by means of computed tomography. A method often applied is to project the largest target volume scan on the plane of the central ray and to calculate the dose in this plane. This method does not allow to take into account any change of the target volume scan which will be mainly due to the body contours of the patient. The results of dose calculations made in several planes for pharyngeal and laryngeal tumors are presented. With this procedure, 33 out of 60 irradiation techniques for nine tumor sites meet the requirements with regard to the central ray plane. If several planes are regarded, this is only true for ten irradiation plans. If is therefore absolutely necessary to calculate the doses of several planes if the target volume has an irregular shape or if the body contours vary considerably. This is the only way to prevent a false treatment caused by possibly severe dose excesses or dose insufficiencies in radiotherapy. (orig.)

  17. Selection and delineation of target volumes in head and neck tumors: beyond ICRU definition

    International Nuclear Information System (INIS)

    Improvement in irradiation techniques, which allows dose distributions sculpting around volumes of very complex shapes, has revealed the limitations in selection and delineation of target volumes. The use of functional imaging (PET, fMRI) in addition to anatomic imaging, will probably bring an extra level of complexity to this issue. In particular, the use of specific markers to visualize biological pathways known to influence response to ionizing radiation (e.g. hypoxia, proliferation) could lead to the delineation of sub-target volumes for delivering an extra boost dose. Such concept of Image-Guided Radiation Therapy still need to be tested in experimental models and in well defined clinical situations before its use in a routine clinical set-up. (author)

  18. Target Centroid Position Estimation of Phase-Path Volume Kalman Filtering

    Directory of Open Access Journals (Sweden)

    Fengjun Hu

    2016-01-01

    Full Text Available For the problem of easily losing track target when obstacles appear in intelligent robot target tracking, this paper proposes a target tracking algorithm integrating reduced dimension optimal Kalman filtering algorithm based on phase-path volume integral with Camshift algorithm. After analyzing the defects of Camshift algorithm, compare the performance with the SIFT algorithm and Mean Shift algorithm, and Kalman filtering algorithm is used for fusion optimization aiming at the defects. Then aiming at the increasing amount of calculation in integrated algorithm, reduce dimension with the phase-path volume integral instead of the Gaussian integral in Kalman algorithm and reduce the number of sampling points in the filtering process without influencing the operational precision of the original algorithm. Finally set the target centroid position from the Camshift algorithm iteration as the observation value of the improved Kalman filtering algorithm to fix predictive value; thus to make optimal estimation of target centroid position and keep the target tracking so that the robot can understand the environmental scene and react in time correctly according to the changes. The experiments show that the improved algorithm proposed in this paper shows good performance in target tracking with obstructions and reduces the computational complexity of the algorithm through the dimension reduction.

  19. Lymphatic atlas-based target volume definition for intensity-modulated radiation therapy planning

    International Nuclear Information System (INIS)

    Despite the improvements in current imaging modalities such as CT and MRI, the detection of normal or malignant lymph nodes remains a challenge due to the large variability in lymph node characteristics and the variation in imaging quality and the limited imaging resolution. A computerized lymph node atlas could be the ideal tool for target volume definition based on the distribution of normal lymph nodes surrounding the verified malignant nodes to improve the accuracy of intensity-modulated radiation therapy planning. The standard lymph node topography in the newly constructed 3D lymph node atlas offers a detailed topographical distribution of discrete nodal locations in relation to surrounding organs at risk. In the present paper, the recently developed lymph node atlas is used for selection and delineation of target volumes in the head and neck, thorax and pelvic region. Image registration techniques were implemented to integrate the topography of the lymph node atlas into the patient's data set. By combining the knowledge-based lymph node distribution with the patient's data set, more detailed definitions of the target volumes were obtained to facilitate biologically based treatment plan optimization. The response values of the biologically optimized treatment plans were used to derive the probability of tumor control and the probability of complications in organs at risk. The treatment outcome of the lung reference plan showed a lower probability of recurrence in comparison to planning without the lymph node atlas. The lymph node atlas can improve and standardize the target volume definition by including more accurate anatomical knowledge for target volume definition and biologically optimized radiation therapy planning

  20. The use of positron emission tomography/computed tomography imaging in radiation therapy: a phantom study for setting internal target volume of biological target volume

    International Nuclear Information System (INIS)

    Fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is an important method for detecting tumours, planning radiotherapy treatment, and evaluating treatment responses. However, using the standardized uptake value (SUV) threshold with PET imaging may be suitable not to determine gross tumour volume but to determine biological target volume (BTV). The aim of this study was to extract internal target volume of BTV from PET images. Three spherical densities of 18F-FDG were employed in a phantom with an air or water background with repetitive motion amplitudes of 0–30 mm. The PET data were reconstructed with attenuation correction (AC) based on CT images obtained by slow CT scanning (SCS) or helical CT scanning (HCS). The errors in measured SUVmax and volumes calculated using SUV threshold values based on SUVmax (THmax) in experiments performed with varying extents of respiratory motion and AC were analysed. A partial volume effect (PVE) was not observed in spheres with diameters of ≥ 28 mm. When calculating SUVmax and THmax, using SCS for AC yielded smaller variance than using HCS (p < 0.05). For spheres of 37- and 28-mm diameters in the phantom with either an air or water background, significant differences were observed when mean THmax of 30-, 20-, or 10-mm amplitude were compared with the stationary conditions (p < 0.05). The average THmax values for 37-mm and 28-mm spheres with an air background were 0.362 and 0.352 in non-motion, respectively, and the mean THmax values for 37-mm and 28-mm spheres with a water background were 0.404 and 0.387 in non-motion and 0.244 and 0.263 in motion, respectively. When the phantom background was air, regardless of sphere concentration or size, THmax was dependent only on motion amplitude. We found that there was no PVE for spheres with ≥ 28-mm diameters, and differences between SUVmax and THmax were reduced by using SCS for AC. In the head-and-neck and the abdomen, the standard values of

  1. The effect of image-guided radiation therapy on the margin between the clinical target volume and planning target volume in lung cancer

    International Nuclear Information System (INIS)

    Introduction: This study aimed to evaluate the effect of image-guided radiation therapy (IGRT) on the margin between the clinical target volume (CTV) and planning target volume (PTV) in lung cancer. Methods: The CTV and PTV margin were determined in three dimensions by four radiation oncologists using a standard method in 10 lung cancer patients, and compared to consensus values. Transfer error was measured using a rigid phantom containing gold markers. Systematic error and random error set up errors were calculated in three dimensions from pre-treatment and post-treatment cone beam CT scans. Finally, the margin between the CTV and PTV was corrected for set up error and calculated. Results: The margins between the CTV and PTV with IGRT (and without IGRT) were 0.88 cm (0.96 cm), 0.99 cm (1.08 cm) and 1.28 cm (1.82 cm) in the anterior and posterior (AP), left and right (LR) and superior and inferior (SI) directions, respectively. Images from two other patients verified the validity of the corrected margin. The target delineation errors of the radiation oncologists are considered to be the largest compared with the set up errors. The application of IGRT reduced the set up errors and the margins between CTV and PTV. Conclusions: The delineation errors of radiation oncologists are the most important factor to consider for the margin between CTV and PTV for lung cancer. IGRT can reduce the margins by reducing the set up errors, especially in the SI direction. Further research is required to assess whether the reduction in the margin is solely based on set up errors

  2. The effect of image-guided radiation therapy on the margin between the clinical target volume and planning target volume in lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jun; Li, Minghui; Zhang, Tao; Han, Wei; Chen, Dongfu; Hui, Zhouguang; Lv, Jima; Zhang, Zhong; Zhang, Yin; Zhang, Liansheng; Zheng, Rong; Dai, Jianrong; Wang, Luhua, E-mail: wlhwq@yahoo.com [Department of Radiotherapy, Cancer Hospital, Chinese Academy of Medical Sciences, Beijing (China)

    2014-02-15

    Introduction: This study aimed to evaluate the effect of image-guided radiation therapy (IGRT) on the margin between the clinical target volume (CTV) and planning target volume (PTV) in lung cancer. Methods: The CTV and PTV margin were determined in three dimensions by four radiation oncologists using a standard method in 10 lung cancer patients, and compared to consensus values. Transfer error was measured using a rigid phantom containing gold markers. Systematic error and random error set up errors were calculated in three dimensions from pre-treatment and post-treatment cone beam CT scans. Finally, the margin between the CTV and PTV was corrected for set up error and calculated. Results: The margins between the CTV and PTV with IGRT (and without IGRT) were 0.88 cm (0.96 cm), 0.99 cm (1.08 cm) and 1.28 cm (1.82 cm) in the anterior and posterior (AP), left and right (LR) and superior and inferior (SI) directions, respectively. Images from two other patients verified the validity of the corrected margin. The target delineation errors of the radiation oncologists are considered to be the largest compared with the set up errors. The application of IGRT reduced the set up errors and the margins between CTV and PTV. Conclusions: The delineation errors of radiation oncologists are the most important factor to consider for the margin between CTV and PTV for lung cancer. IGRT can reduce the margins by reducing the set up errors, especially in the SI direction. Further research is required to assess whether the reduction in the margin is solely based on set up errors.

  3. Optimized planning target volume margin in helical tomotherapy for prostate cancer: is there a preferred method?

    CERN Document Server

    Cao, Yuan Jie; Chang, Kyung Hwan; Shim, Jang Bo; Kim, Kwang Hyeon; Jang, Min Sun; Yoon, Won Sup; Yang, Dae Sik; Park, Young Je; Kim, Chul Yong

    2015-01-01

    To compare the dosimetrical differences between plans generated by helical tomotherapy using 2D or 3D margining technique in in prostate cancer. Ten prostate cancer patients were included in this study. For 2D plans, planning target volume (PTV) was created by adding 5 mm (lateral/anterior-posterior) to clinical target volume (CTV). For 3D plans, 5 mm margin was added not only in lateral/anterior-posterior, but also in superior-inferior to CTV. Various dosimetrical indices, including the prescription isodose to target volume (PITV) ratio, conformity index (CI), homogeneity index (HI), target coverage index (TCI), modified dose homogeneity index (MHI), conformation number (CN), critical organ scoring index (COSI), and quality factor (QF) were determined to compare the different treatment plans. Differences between 2D and 3D PTV indices were not significant except for CI (p = 0.023). 3D margin plans (11195 MUs) resulted in higher (13.0%) monitor units than 2D margin plans (9728 MUs). There were no significant d...

  4. Target volume and position variations during intensity-modulated radiotherapy for patients with nasopharyngeal carcinoma

    Directory of Open Access Journals (Sweden)

    Tan W

    2013-11-01

    Full Text Available Wenyong Tan,* Yanping Li,* Guang Han, Jiaozhen Xu, Xiaohong Wang, Ying Li, Desheng HuDepartment of Radiation Oncology, Hubei Cancer Hospital, Wuhan, People's Republic of China*These authors contributed equally to this workPurpose: Considerable anatomical changes occur during intensity-modulated radiotherapy (IMRT for nasopharyngeal carcinoma (NPC. This study aimed to quantify volumetric and positional variations of the target volume during IMRT.Materials and methods: Twenty patients with locally advanced NPC who received concurrent (13 patients or sequential (seven patients chemoradiotherapy were prospectively recruited and underwent planning computed tomography (CT and six repeat CTs (every five fractions. Each repeat CT was rigidly registered to the planning CT. Gross tumor volume (GTV and elective clinical target volume (CTV were manually delineated on each axial CT image. CTVs of the primary tumor and lymph nodes were expanded with 5 mm margins to corresponding GTVs, with necessary modifications. Volume loss, system and random errors, and the mean and three-dimensional vector displacements were calculated and compared statistically.Results: Volumes of the primary tumor and small (>1 cm, ≤3 cm and large (>3 cm positive neck lymph nodes decreased at a rate of 2.6%, 3.7%, and 3.9% per treatment day, respectively. CTVs of the primary tumor, lymph nodes, and elective region decreased 1.5%, 2.3%, and 0.3% per treatment day, respectively. Average displacements of the GTVs and CTVs were <1.3 mm in all directions. GTVs and CTVs of the large and small lymph nodes shifted medially by 0.8–1.3 and 0.6–1.2 mm, respectively, on average. Average three-dimensional displacements of the GTVs and CTVs were 3.4–4.3 mm and 2.5–3.7 mm, respectively. Volume loss and displacements in most directions were significantly larger in patients receiving concurrent chemoradiotherapy than in those receiving sequential therapy. Volume loss and displacements of the

  5. Role of PET/CT functional imaging on constructing a tumor radiotherapeutic biological target volume

    International Nuclear Information System (INIS)

    In studies on intensity modulated radiotherapy with conventional fractionation, different radiosensitivity areas require different irradiation doses. In tumor radiotherapy areas CR, boosts in radiotherapy doses should be determined according to whether there are survived tumor cells or not. To those survived cells, CT imaging has become the key tool to delineate the radiotherapy target. Thus, the study on the construction of biological target volume with PET/CT functional imaging, which could reflect either radiosensitivity or cell proliferation-related cell metabolism, anoxia and DNA number of various cell cycle phases, is an important research area. (authors)

  6. Guidelines for delineation of lymphatic clinical target volumes for high conformal radiotherapy: head and neck region

    International Nuclear Information System (INIS)

    The success of radiotherapy depends on the accurate delineation of the clinical target volume. The delineation of the lymph node regions has most impact, especially for tumors in the head and neck region. The purpose of this article was the development an atlas for the delineation of the clinical target volume for patients, who should receive radiotherapy for a tumor of the head and neck region. Literature was reviewed for localisations of the adjacent lymph node regions and their lymph drain in dependence of the tumor entity. On this basis the lymph node regions were contoured on transversal CT slices. The probability for involvement was reviewed and a recommendation for the delineation of the CTV was generated

  7. SU-E-T-578: On Definition of Minimum and Maximum Dose for Target Volume

    International Nuclear Information System (INIS)

    Purpose: This study aims to investigate the impact of different minimum and maximum dose definitions in radiotherapy treatment plan quality evaluation criteria by using tumor control probability (TCP) models. Methods: Dosimetric criteria used in RTOG 1308 protocol are used in the investigation. RTOG 1308 is a phase III randomized trial comparing overall survival after photon versus proton chemoradiotherapy for inoperable stage II-IIIB NSCLC. The prescription dose for planning target volume (PTV) is 70Gy. Maximum dose (Dmax) should not exceed 84Gy and minimum dose (Dmin) should not go below 59.5Gy in order for the plan to be “per protocol” (satisfactory).A mathematical model that simulates the characteristics of PTV dose volume histogram (DVH) curve with normalized volume is built. The Dmax and Dmin are noted as percentage volumes Dη% and D(100-δ)%, with η and d ranging from 0 to 3.5. The model includes three straight line sections and goes through four points: D95%= 70Gy, Dη%= 84Gy, D(100-δ)%= 59.5 Gy, and D100%= 0Gy. For each set of η and δ, the TCP value is calculated using the inhomogeneously irradiated tumor logistic model with D50= 74.5Gy and γ50=3.52. Results: TCP varies within 0.9% with η; and δ values between 0 and 1. With η and η varies between 0 and 2, TCP change was up to 2.4%. With η and δ variations from 0 to 3.5, maximum of 8.3% TCP difference is seen. Conclusion: When defined maximum and minimum volume varied more than 2%, significant TCP variations were seen. It is recommended less than 2% volume used in definition of Dmax or Dmin for target dosimetric evaluation criteria. This project was supported by NIH grants U10CA180868, U10CA180822, U24CA180803, U24CA12014 and PA CURE Grant

  8. SU-E-T-578: On Definition of Minimum and Maximum Dose for Target Volume

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Y; Yu, J; Xiao, Y [Thomas Jefferson University Hospital, Philadelphia, PA (United States)

    2015-06-15

    Purpose: This study aims to investigate the impact of different minimum and maximum dose definitions in radiotherapy treatment plan quality evaluation criteria by using tumor control probability (TCP) models. Methods: Dosimetric criteria used in RTOG 1308 protocol are used in the investigation. RTOG 1308 is a phase III randomized trial comparing overall survival after photon versus proton chemoradiotherapy for inoperable stage II-IIIB NSCLC. The prescription dose for planning target volume (PTV) is 70Gy. Maximum dose (Dmax) should not exceed 84Gy and minimum dose (Dmin) should not go below 59.5Gy in order for the plan to be “per protocol” (satisfactory).A mathematical model that simulates the characteristics of PTV dose volume histogram (DVH) curve with normalized volume is built. The Dmax and Dmin are noted as percentage volumes Dη% and D(100-δ)%, with η and d ranging from 0 to 3.5. The model includes three straight line sections and goes through four points: D95%= 70Gy, Dη%= 84Gy, D(100-δ)%= 59.5 Gy, and D100%= 0Gy. For each set of η and δ, the TCP value is calculated using the inhomogeneously irradiated tumor logistic model with D50= 74.5Gy and γ50=3.52. Results: TCP varies within 0.9% with η; and δ values between 0 and 1. With η and η varies between 0 and 2, TCP change was up to 2.4%. With η and δ variations from 0 to 3.5, maximum of 8.3% TCP difference is seen. Conclusion: When defined maximum and minimum volume varied more than 2%, significant TCP variations were seen. It is recommended less than 2% volume used in definition of Dmax or Dmin for target dosimetric evaluation criteria. This project was supported by NIH grants U10CA180868, U10CA180822, U24CA180803, U24CA12014 and PA CURE Grant.

  9. Definition of a moving gross target volume for stereotactic radiation therapy of stented coronary arteries

    International Nuclear Information System (INIS)

    Purpose: To measure the effect of cardiac motion on coronary artery stent position during the cardiac cycle as a first step toward exploring the feasibility of stereotactic external beam radiation therapy targeted at restenotic stented coronary arteries. Methods and Materials: The three-dimensional (3D) position of eight coronary artery stents in 8 patients immobilized in a stereotactic body frame was studied noninvasively by single-breathhold ECG-gated multislice spiral computed tomography (MSCT) during 10 retrospectively selected phases, equally distributed throughout the R-R interval of consecutive cardiac cycles. The volume encompassing all measured 3D positions of the stent was measured. Results: Stent volumes measured by MSCT closely agreed with measurements by quantitative coronary angiography (r > 0.99). The mean of the maximum 3D stent center of mass displacement between any two phases during the cardiac cycle for all eight coronary arteries was 7.5 mm (range 3.3-20.5 mm) in the lateral direction, 8.6 mm (range 2.7-21.6 mm) in the ventrodorsal direction, and 8.2 mm (range 2.5-19.7 mm) in the craniocaudal direction. As was anticipated, the volume encompassing all measured 3D positions of the stent represented only a fraction of the whole heart volume in all patients, i.e., less than 0.6%. Conclusions: ECG-gated MSCT allowed the measurement of the volume encompassing multiphase 3D positions of coronary artery stents during the cardiac cycle. This volume, a measure of the cardiac motion effect on coronary artery stent position during the cardiac cycle, represents a moving gross target for stereotactic external beam radiation therapy

  10. Gold markers for tumor localization and target volume delineation in radiotherapy for rectal cancer

    International Nuclear Information System (INIS)

    In locally advanced rectal cancer, neoadjuvant radiochemotherapy is indicated. To improve target volume definition for radiotherapy planning, the potential of implanted gold markers in the tumor region was evaluated. In nine consecutive patients, two to three gold markers were implanted in the tumor region during rigid rectoscopy. Computed tomography scans were performed during treatment planning. All electronic portal imaging devices (EPIDs) recorded during treatment series were analyzed. All patients underwent complete tumor resection with meticulous histopathologic examination. The gold markers could easily be implanted into the mesorectal tissue at the caudal tumor border without any complications. They were helpful in identifying the inferior border of the planning target volume in order to spare normal tissue (in particular anal structures). No significant shift of the markers was found during the course of therapy. Marker matching of the EPIDs did not improve patient positioning in comparison to bone structure matching. The former position of at least one marker could be identified in all patients during histopathologic examination. The use of gold marker enables a more precise definition of the target volume for radiotherapy in patients with rectal cancer. This could eventually allow a better protection of anal structures of patients with a tumor localization = 5 cm cranial of the anal sphincter. The implantation of the gold markers improved communication between the surgeon, the radiooncologist and the pathologist resulting in intensified exchange of relevant informations. (orig.)

  11. Apparent diffusion coefficients in GEC ESTRO target volumes for image guided adaptive brachytherapy of locally advanced cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Haack, Soeren (Dept. of Clinical Engineering, Aarhus Univ. Hospital (Denmark)), E-mail: Soeren.haack@stab.rm.dk; Morre Pedersen, Erik (Dept. of Radiology, Aarhus Sygehus, Aarhus Univ. Hospital (Denmark)); Jespersen, Sune N. (Center of Functionally Integrative Neuroscience, Aarhus Univ. Hospital (Denmark)); Kallehauge, Jesper F. (Dept. of Medical Physics, Aarhus Univ. Hospital (Denmark)); Lindegaard, Jacob Christian; Tanderup, Kari (Dept. of Oncology Aarhus Univ. Hospital (Denmark))

    2010-10-15

    Background and purpose. T2 weighted MRI is recommended for image guided adaptive brachytherapy (IGABT) in cervical cancer. Diffusion weighted imaging (DWI) and the derived apparent diffusion coefficient (ADC) may add additional biological information on tumour cell density. The purpose of this study was to evaluate the distribution of the ADC within target volumes as recommended by GEC-ESTRO: Gross Tumour Volume at BT (GTVBT), High-Risk Clinical Tumour Volume (HR-CTV) and Intermediate-Risk Clinical Target Volume (IR-CTV) and to evaluate the change of diffusion between fractions of IGABT. Material and methods. Fifteen patients with locally advanced cervical cancer were examined by MRI before their first (BT1) and second (BT2) fraction of IGABT, resulting in a total of 30 MR examinations including both T2 weighted and DWI sequences. The Apparent Diffusion Coefficient (ADC) was calculated by use of three levels of b-values (0, 600, 1000 s/mm2). ADC maps were constructed and fused with the GEC ESTRO target contours. The mean ADC value within each target volume was calculated. Furthermore, volumes of low diffusion (ADClow) were defined based on an ADC threshold of 1.2 x 10-3 mm2/s, and overlap with target volumes was evaluated. Change of ADC level in target volumes and change of ADClow volume from BT1 to BT2 was also evaluated. Results. The mean ADC was significantly lower in GTVBT than in HR-CTV (p<0.001) which again was significantly lower than in IR-CTV (p<0.001). There was no significant change of the ADClow volume or ADC level within each target structure between BT1 and BT2 (p=0.242). All three GEC-ESTRO volumes contained volumes with low diffusion. The GTVBT contained 37.2% volume of low diffusion, HR-CTV 20.3% and IR-CTV 10.8%. Conclusion. With DWI we were able to find a significant difference in ADC-values for the three different GEC ESTRO targets. This supports the assumption that the target volumes used for dose prescription in IGABT contain tissues with

  12. Reproducibility of target volumes generated using uncoached 4-dimensional CT scans for peripheral lung cancer

    International Nuclear Information System (INIS)

    4-dimensional CT (4DCT) scans are increasingly used to account for mobility during radiotherapy planning. As variations in respiratory patterns can alter observed motion, with consequent changes in the generated target volumes, we evaluated the reproducibility of 4D target volumes generated during repeat uncoached quiet respiration. A retrospective analysis was performed on two successive scans (4DCT1 and 4DCT2) generated at the same scanning session for 26 patients with peripheral lung cancer treated with stereotactic radiotherapy (SRT). The volume and position of planning target volumes (PTV4DCT1 and PTV4DCT2) contoured on both scans were compared, and a dosimetric analysis performed. A SRT plan optimized for each PTV was sequentially applied to the other PTV, and coverage by the 80% isodose was evaluated. Color intensity projections (CIP) were used to evaluate regions of underdosage. No significant volumetric differences were observed between the two PTVs (t-Test p = 0.60). The average displacement of the center of mass between corresponding PTVs was 1.4 ± 1.0 mm, but differences in position were 2.0 mm or greater in 5 cases (19%). Coverage of both PTVs by the 80% prescription isodose exceeded 90% for all but one patient. For the latter, the prescription isodose covered only 82.5% of PTV4DCT1. CIP analysis revealed that the region of underdosage was an end-inspiratory position occupied by the tumor for only 10–20% of the respiratory cycle. In nearly all patients with stage I lung cancer, the PTV derived from a single uncoached 4DCT achieves dosimetric coverage that is similar to that achieved using two such consecutive scans

  13. Optimized planning target volume margin in helical tomotherapy for prostate cancer: Is there a preferred method?

    Science.gov (United States)

    Cao, Yuan Jie; Lee, Suk; Chang, Kyung Hwan; Shim, Jang Bo; Kim, Kwang Hyeon; Jang, Min Sun; Yoon, Won Sup; Yang, Dae Sik; Park, Young Je; Kim, Chul Yong

    2015-07-01

    We compare the dosimetrical differences between plans generated for helical tomotherapy by using the 2D or 3D the margining technique for the treatment of prostate cancer. Ten prostate cancer patients were included in this study. For 2D plans, the planning target volume (PTV) was created by adding 5 mm (lateral/anterior-posterior) to the clinical target volume (CTV). For 3D plans, a 5-mm margin was added not only lateral/anterior-posterior, but also superior-inferior, to the CTV. Various dosimetrical indices, including the prescription isodose to target volume (PITV) ratio, conformity index (CI), homogeneity index (HI), target coverage index (TCI), modified dose homogeneity index (MHI), conformation number (CN), critical organ scoring index (COSI), and quality factor (QF) were determined to compare the different treatment plans. Differences between the 2D and the 3D PTV indices were not significant except for the CI (p = 0.023). 3D margin plans (11195 MUs) resulted in higher (13.0%) monitor units than 2D margin plans (9728 MUs). There were no significant differences in any organs at risk (OARs) between the 2D and the 3D plans. Overall, the average dose for the 2D plan was slightly lower than that for the 3D plan dose. Compared to the 2D plan, the 3D plan increased the average treatment time by 1.5 minutes; however, this difference was not statistically significant (p = 0.082). We confirmed that the 2D and the 3D margin plans were not significantly different with regard to various dosimetric indices such as the PITV, CI, and HI for PTV and the OARs with tomotherapy.

  14. A prospective study of nomogram-based adaptation of prostate radiotherapy target volumes

    International Nuclear Information System (INIS)

    A prospective clinical trial was conducted to evaluate the feasibility of a novel approach to the treatment of patients with high risk prostate cancer (HRPC) through the use of a nomogram to tailor radiotherapy target volumes. Twenty seven subjects with HRPC were treated with a mildly hypofractionated radiotherapy regimen using image-guided IMRT technique between Jun/2013-Jan/2015. A set of validated prognostic factors were inputted into the Memorial-Sloan-Kettering Cancer Center (MSKCC) prostate cancer nomogram to estimate risk of loco-regional spread (LRS). The nomogram risk estimates for extra-capsular extension (ECE), seminal vesicles involvement (SVI), and pelvic lymph nodes involvement (LNI) were used to adapt radiotherapy treatment volumes based on a risk threshold of ≥15 % in all cases. A planning guide was used to delineate target volumes and organs at risk (OAR). Up to three dose levels were administered over 28 fractions; 70Gy for gross disease in the prostate +/− seminal vesicles (2.5Gy/fraction), 61.6Gy for subclinical peri-prostatic disease (2.2Gy/fraction) and 50.4Gy to pelvic nodes (1.8Gy/fraction). Data regarding protocol adherence, nomogram use, radiotherapy dose distribution, and acute toxicity were collected. Nomogram use 100 % of patients were treated for ECE, 88.9 % for SVI, and 70.4 % for LNI. The three areas at risk of LRS were appropriately treated according to the study protocol in 98.8 % cases. The MSKCC nomogram estimates for LRS differed significantly between the time of recruitment and analysis. Contouring protocol compliance Compliance with the trial contouring protocol for up to seven target volumes was 93.0 % (159/171). Compliance with protocol for small bowel contouring was poor (59.3 %). Dose constraints compliance Compliance with dose constraints for target volumes was 97.4 % (191/196). Compliance with dose constraints for OAR was 88.2 % (285/323). Acute toxicity There were no grade 3 acute toxicities observed. 20/27 (74

  15. Integration of three-dimensional magnetic resonance spectrometry to the irradiation treatment plan for glioblastomas: definition of new target volumes

    International Nuclear Information System (INIS)

    Based on a clinic trial, the authors report the definition of a new reliable and reproducible method to delimit and integrate targets to the treatment plan which are specific to magnetic resonance spectrometry imagery for the radiotherapy of glioblastomas, in order to perform a treatment by intensity-modulated conformational radiotherapy (IMRT). A weighted conventional MRI has been performed before radiotherapy. The importation of anatomic-metabolic images into the dose planning system comprises two steps: normalization on the whole volume of magnetic resonance spectrometry imagery, and segmentation of target volumes specific to spectrometry anomalies. This integration of target volumes is thus facilitated. Short communication

  16. Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was to evaluate the variability in target volume and organ at risk (OAR) contour delineation for retroperitoneal sarcoma (RPS) among 12 sarcoma radiation oncologists. Methods and Materials: Radiation planning computed tomography (CT) scans for 2 cases of RPS were distributed among 12 sarcoma radiation oncologists with instructions for contouring gross tumor volume (GTV), clinical target volume (CTV), high-risk CTV (HR CTV: area judged to be at high risk of resulting in positive margins after resection), and OARs: bowel bag, small bowel, colon, stomach, and duodenum. Analysis of contour agreement was performed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics. Results: Ten radiation oncologists contoured both RPS cases, 1 contoured only RPS1, and 1 contoured only RPS2 such that each case was contoured by 11 radiation oncologists. The first case (RPS 1) was a patient with a de-differentiated (DD) liposarcoma (LPS) with a predominant well-differentiated (WD) component, and the second case (RPS 2) was a patient with DD LPS made up almost entirely of a DD component. Contouring agreement for GTV and CTV contours was high. However, the agreement for HR CTVs was only moderate. For OARs, agreement for stomach, bowel bag, small bowel, and colon was high, but agreement for duodenum (distorted by tumor in one of these cases) was fair to moderate. Conclusions: For preoperative treatment of RPS, sarcoma radiation oncologists contoured GTV, CTV, and most OARs with a high level of agreement. HR CTV contours were more variable. Further clarification of this volume with the help of sarcoma surgical oncologists is necessary to reach consensus. More attention to delineation of the duodenum is also needed

  17. Variation of clinical target volume definition in three-dimensional conformal radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Purpose: Currently, three-dimensional conformal radiation therapy (3D-CRT) planning relies on the interpretation of computed tomography (CT) axial images for defining the clinical target volume (CTV). This study investigates the variation among multiple observers to define the CTV used in 3D-CRT for prostate cancer. Methods and Materials: Seven observers independently delineated the CTVs (prostate ± seminal vesicles [SV]) from the CT simulation data of 10 prostate cancer patients undergoing 3D-CRT. Six patients underwent CT simulation without the use of contrast material and serve as a control group. The other 4 had urethral and bladder opacification with contrast medium. To determine interobserver variation, we evaluated the derived volume, the maximum dimensions, and the isocenter for each examination of CTV. We assessed the reliability in the CTVs among the observers by correlating the variation for each class of measurements. This was estimated by intraclass correlation coefficient (ICC), with 1.00 defining absolute correlation. Results: For the prostate volumes, the ICC was 0.80 (95% confidence interval [CI]: 0.56-0.96). This changed to 0.92 (95% CI: 0.75-0.99) with the use of contrast material. Similarly, the maximal prostatic dimensions were reliable and improved. There was poor agreement in defining the SV. For this structure, the ICC never exceeded 0.28. The reliability of the isocenter was excellent, with the ICC exceeding 0.83 and 0.90 for the prostate ± SV, respectively. Conclusions: In 3D-CRT for prostate cancer, there was excellent agreement among multiple observers to define the prostate target volume but poor agreement to define the SV. The use of urethral and bladder contrast improved the reliability of localizing the prostate. For all CTVs, the isocenter was very reliable and should be used to compare the variation in 3D dosimetry among multiple observers

  18. Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists

    Energy Technology Data Exchange (ETDEWEB)

    Baldini, Elizabeth H., E-mail: ebaldini@partners.org [Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Abrams, Ross A. [Department of Radiation Oncology, Rush University Medical Center, Chicago, Illinois (United States); Bosch, Walter [Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States); Roberge, David [Department of Radiation Oncology, Centre Hospitalier de l' Universite de Montreal, Montreal, Quebec (Canada); Haas, Rick L.M. [Department of Radiotherapy, Netherlands Cancer Institute, Amsterdam (Netherlands); Catton, Charles N. [Department of Radiation Oncology, Princess Margaret Cancer Centre, Toronto, Ontario (Canada); Indelicato, Daniel J. [Department of Radiation Oncology, University of Florida Medical Center, Jacksonville, Florida (United States); Olsen, Jeffrey R. [Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States); Deville, Curtiland [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Chen, Yen-Lin [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Finkelstein, Steven E. [Translational Research Consortium, 21st Century Oncology, Scottsdale, Arizona (United States); DeLaney, Thomas F. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Wang, Dian [Department of Radiation Oncology, Rush University Medical Center, Chicago, Illinois (United States)

    2015-08-01

    Purpose: The purpose of this study was to evaluate the variability in target volume and organ at risk (OAR) contour delineation for retroperitoneal sarcoma (RPS) among 12 sarcoma radiation oncologists. Methods and Materials: Radiation planning computed tomography (CT) scans for 2 cases of RPS were distributed among 12 sarcoma radiation oncologists with instructions for contouring gross tumor volume (GTV), clinical target volume (CTV), high-risk CTV (HR CTV: area judged to be at high risk of resulting in positive margins after resection), and OARs: bowel bag, small bowel, colon, stomach, and duodenum. Analysis of contour agreement was performed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics. Results: Ten radiation oncologists contoured both RPS cases, 1 contoured only RPS1, and 1 contoured only RPS2 such that each case was contoured by 11 radiation oncologists. The first case (RPS 1) was a patient with a de-differentiated (DD) liposarcoma (LPS) with a predominant well-differentiated (WD) component, and the second case (RPS 2) was a patient with DD LPS made up almost entirely of a DD component. Contouring agreement for GTV and CTV contours was high. However, the agreement for HR CTVs was only moderate. For OARs, agreement for stomach, bowel bag, small bowel, and colon was high, but agreement for duodenum (distorted by tumor in one of these cases) was fair to moderate. Conclusions: For preoperative treatment of RPS, sarcoma radiation oncologists contoured GTV, CTV, and most OARs with a high level of agreement. HR CTV contours were more variable. Further clarification of this volume with the help of sarcoma surgical oncologists is necessary to reach consensus. More attention to delineation of the duodenum is also needed.

  19. A treatment planning comparison of four target volume contouring guidelines for locally advanced pancreatic cancer radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: Contouring of target volumes varies significantly in radiotherapy of pancreatic ductal adenocarcinoma (PDAC). There is a lack of consensus as to whether elective lymph nodes (eLN’s) should be included or not in the planning target volume (PTV). In the present study we analyzed the dosimetric coverage of the eLN’s and organs at risk (OAR) by comparing four different contouring guidelines. Methods and materials: PTVs were delineated with (Oxford and RTOG guidelines) or without (Michigan and SCALOP guidelines) including the eLNs in eleven patients with PDAC. eLNs included the peripancreatic, paraaortic, paracaval, celiac trunk, superior mesenteric and portal vein clinical target volumes (CTVs). A 3D-CRT plan (50.40 Gy in 28 fractions) was performed to analyze and compare the dosimetric coverage of all eLNs and OAR between the 4 contouring guidelines. Results: The size of Oxford and RTOG PTVs was comparable and significantly larger than the SCALOP and Michigan PTVs. Interestingly the eLNs received a significant amount of incidental dose irradiation by PTV-based plans that only aimed to treat the tumor without the eLNs. The dosimetric coverage of eLN presented a large variability according to the respective contouring methods. The difference in the size of the 4 PTVs was reflected to the dose distribution at the OAR. Conclusions: Our study provides important information regarding the impact of different contouring guidelines on the dose distribution to the eLNs and the OAR in patients with locally advanced PDAC treated with radiotherapy

  20. Planning target volume (PTV) definition and its effects in the radiotherapy

    International Nuclear Information System (INIS)

    Tills work intends to study the margins required to define a planning target volume (PTV) for adequate treatment of the mobile tumors such as prostate or those located in areas with less mobility as the ones in head and neck region, in the absence of daily localization imaging based. It is also intends to evaluate the impact caused by the PTV, in terms of dose, to the critical structures surrounding the PTV and its influence when inverse planning is used in the intensity-modulated radiation therapy (IMRT). Data from 387 prostate patients were analyzed retrospectively. Every patient in the study received daily pre-treatment localization with 2D ultrasound resulting in a total of 10,327 localizations, each comprising of an isocenter displacement in 3 directions: anterior-posterior (AP), right-left lateral (RL), and superior-inferior (SI). The mean displacement and standard deviation (SD) for each direction for each patient was computed from daily treatment records. The uncertainties (SD) in the target position were 4.4 mm (AP), 3.6 mm (RL), and 4.5 mm (SI). A study of the uncertainties in the daily positioning of 78 head and neck patients who used thermoplastic mask to immobilize them, evaluated with electronic portal imaging device (EPID), showed variations (SD) in the isocenter treatment position of 3.1 mm (AP), 1.5 mm (RL), and 4.5 mm (SI). By applying these shifts in an anthropomorphic phantom it was studied the dose-volume histograms resultant of the isocenter displacement in the daily treatment. The result showed the importance of putting margins in the clinical target volume to assure an adequate treatment and also showed that isocenter daily variation can cause an increase to the dose greater than the tolerance level to the critical organs. (author)

  1. A method of calculating a lung clinical target volume DVH for IMRT with intrafractional motion.

    Science.gov (United States)

    Kung, J H; Zygmanski, P; Choi, N; Chen, G T Y

    2003-06-01

    The motion of lung tumors from respiration has been reported in the literature to be as large as 1-2 cm. This motion requires an additional margin between the Clinical Target Volume (CTV) and the Planning Target Volume (PTV). In Intensity Modulated Radiotherapy (IMRT), while such a margin is necessary, the margin may not be sufficient to avoid unintended high and low dose regions to the interior on moving CTV. Gated treatment has been proposed to improve normal tissues sparing as well as to ensure accurate dose coverage of the tumor volume. The following questions have not been addressed in the literature: (a) what is the dose error to a target volume without a gated IMRT treatment? (b) What is an acceptable gating window for such a treatment. In this study, we address these questions by proposing a novel technique for calculating the three-dimensional (3-D) dose error that would result if a lung IMRT plan were delivered without a gated linac beam. The method is also generalized for gated treatment with an arbitrary triggering window. IMRT plans for three patients with lung tumors were studied. The treatment plans were generated with HELIOS for delivery with 6 MV on a CL2100 Varian linear accelerator with a 26 pair MLC. A CTV to PTV margin of 1 cm was used. An IMRT planning system searches for an optimized fluence map phi(x,y) for each port, which is then converted into a dynamic MLC file (DMLC). The DMLC file contains information about MLC subfield shapes and the fractional Monitor Units (MUs) to be delivered for each subfield. With a lung tumor, a CTV that executes a quasiperiodic motion z(t) does not receive phi(x,y), but rather an Effective Incident Fluence EIF(x,y). We numerically evaluate the EIF(x,y) from a given DMLC file by a coordinate transformation to the Target's Eye View (TEV). In the TEV coordinate system, the CTV itself is stationary, and the MLC is seen to execute a motion -z(t) that is superimposed on the DMLC motion. The resulting EIF(x,y) is

  2. A method of calculating a lung clinical target volume DVH for IMRT with intrafractional motion

    International Nuclear Information System (INIS)

    The motion of lung tumors from respiration has been reported in the literature to be as large as 1-2 cm. This motion requires an additional margin between the Clinical Target Volume (CTV) and the Planning Target Volume (PTV). In Intensity Modulated Radiotherapy (IMRT), while such a margin is necessary, the margin may not be sufficient to avoid unintended high and low dose regions to the interior on moving CTV. Gated treatment has been proposed to improve normal tissues sparing as well as to ensure accurate dose coverage of the tumor volume. The following questions have not been addressed in the literature: (a) what is the dose error to a target volume without a gated IMRT treatment? (b) What is an acceptable gating window for such a treatment. In this study, we address these questions by proposing a novel technique for calculating the three-dimensional (3-D) dose error that would result if a lung IMRT plan were delivered without a gated linac beam. The method is also generalized for gated treatment with an arbitrary triggering window. IMRT plans for three patients with lung tumors were studied. The treatment plans were generated with HELIOS for delivery with 6 MV on a CL2100 Varian linear accelerator with a 26 pair MLC. A CTV to PTV margin of 1 cm was used. An IMRT planning system searches for an optimized fluence map Φ(x,y) for each port, which is then converted into a dynamic MLC file (DMLC). The DMLC file contains information about MLC subfield shapes and the fractional Monitor Units (MUs) to be delivered for each subfield. With a lung tumor, a CTV that executes a quasiperiodic motion z(t) does not receive Φ(x,y), but rather an Effective Incident Fluence EIF(x,y). We numerically evaluate the EIF(x,y) from a given DMLC file by a coordinate transformation to the Target's Eye View (TEV). In the TEV coordinate system, the CTV itself is stationary, and the MLC is seen to execute a motion -z(t) that is superimposed on the DMLC motion. The resulting EIF(x,y) is input

  3. Clinical target volume delineation in glioblastomas: pre-operative versus post-operative/pre-radiotherapy MRI

    Science.gov (United States)

    Farace, P; Giri, M G; Meliadò, G; Amelio, D; Widesott, L; Ricciardi, G K; Dall'Oglio, S; Rizzotti, A; Sbarbati, A; Beltramello, A; Maluta, S; Amichetti, M

    2011-01-01

    Objectives Delineation of clinical target volume (CTV) is still controversial in glioblastomas. In order to assess the differences in volume and shape of the radiotherapy target, the use of pre-operative vs post-operative/pre-radiotherapy T1 and T2 weighted MRI was compared. Methods 4 CTVs were delineated in 24 patients pre-operatively and post-operatively using T1 contrast-enhanced (T1PRECTV and T1POSTCTV) and T2 weighted images (T2PRECTV and T2POSTCTV). Pre-operative MRI examinations were performed the day before surgery, whereas post-operative examinations were acquired 1 month after surgery and before chemoradiation. A concordance index (CI) was defined as the ratio between the overlapping and composite volumes. Results The volumes of T1PRECTV and T1POSTCTV were not statistically different (248 ± 88 vs 254 ± 101), although volume differences >100 cm3 were observed in 6 out of 24 patients. A marked increase due to tumour progression was shown in three patients. Three patients showed a decrease because of a reduced mass effect. A significant reduction occurred between pre-operative and post-operative T2 volumes (139 ± 68 vs 78 ± 59). Lack of concordance was observed between T1PRECTV and T1POSTCTV (CI = 0.67 ± 0.09), T2PRECTV and T2POSTCTV (CI = 0.39 ± 0.20) and comparing the portion of the T1PRECTV and T1POSTCTV not covered by that defined on T2PRECTV images (CI = 0.45 ± 0.16 and 0.44 ± 0.17, respectively). Conclusion Using T2 MRI, huge variations can be observed in peritumoural oedema, which are probably due to steroid treatment. Using T1 MRI, brain shifts after surgery and possible progressive enhancing lesions produce substantial differences in CTVs. Our data support the use of post-operative/pre-radiotherapy T1 weighted MRI for planning purposes. PMID:21045069

  4. Residual tumor after neoadjuvant chemoradiation outside the radiation therapy target volume : a new prognostic factor for survival in esophageal cancer

    NARCIS (Netherlands)

    Muijs, Christina; Smit, Justin; Karrenbeld, Arend; Beukema, Jannet C.; Mul, Veronique; van Dam, Go; Hospers, Geke; Kluin, Phillip; Langendijk, Johannes; Plukker, John

    2014-01-01

    PURPOSE/OBJECTIVE(S): The aim of this study was to analyze the accuracy of gross tumor volume (GTV) delineation and clinical target volume (CTV) margins for neoadjuvant chemoradiation therapy (neo-CRT) in esophageal carcinoma at pathologic examination and to determine the impact on survival. METHODS

  5. Residual Tumor After Neoadjuvant Chemoradiation Outside the Radiation Therapy Target Volume : A New Prognostic Factor for Survival in Esophageal Cancer

    NARCIS (Netherlands)

    Muijs, Christina; Smit, Justin; Karrenbeld, Arend; Beukema, J.C.; Mul, Veronique; van Dam, Go; Hospers, Geke; Kluin, Phillip; Langendijk, Johannes; Plukker, John

    2014-01-01

    Purpose/Objective(s): The aim of this study was to analyze the accuracy of gross tumor volume (GTV) delineation and clinical target volume (CTV) margins for neoadjuvant chemoradiation therapy (neo-CRT) in esophageal carcinoma at pathologic examination and to determine the impact on survival. Methods

  6. MRI-assisted specification/localization of target volumes. Aspects of quality control

    International Nuclear Information System (INIS)

    The transportation of MRI information on tumor extension into CT-based radiation therapy planning is desirable for several reasons. MRI's better contrast resolution is usually considered the most important, as it leads to a more exact definition of target volumes. Unlike diagnostic imaging, where a certain margin of error in depiction of tumor extension seems acceptable, radiation therapy planning makes it absolutely necessary, that the contents of very MR pixel (or voxel) correspond exactly to the corresponding area in the patient examined. This exact correspondence may be disturbed by a variety of influencing factors. Objects like various implants may lead to the most severe image distortions and - even worse - contrast alterations, some of which are not easily visible on the slices which are used for target volume definition. Additionally, MR images may have intrinsic faults which are able to change the correspondence between the voxel and the part of the patient's body it represents. Quality control has therefore to ensure that parameters like slice thickness are correct and kept constant by the imager. Image fusion may then be used to transfer MR information on tumor extension into the CT data. Electron density distribution provided by CT then allows for treatment planning. Implanted markers may then be used to ensure exact correspondence between the examined parts of the patient's body and the representing pixel or voxel. Care should be taken that landmarks themselves do not influence this relationship. (orig.)

  7. Dosimetric Advantages of Midventilation Compared With Internal Target Volume for Radiation Therapy of Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lens, Eelco, E-mail: e.lens@amc.uva.nl; Horst, Astrid van der; Versteijne, Eva; Tienhoven, Geertjan van; Bel, Arjan

    2015-07-01

    Purpose: The midventilation (midV) approach can be used to take respiratory-induced pancreatic tumor motion into account during radiation therapy. In this study, the dosimetric consequences for organs at risk and tumor coverage of using a midV approach compared with using an internal target volume (ITV) were investigated. Methods and Materials: For each of the 18 patients, 2 treatment plans (25 × 2.0 Gy) were created, 1 using an ITV and 1 using a midV approach. The midV dose distribution was blurred using the respiratory-induced motion from 4-dimensional computed tomography. The resulting planning target volume (PTV) coverage for this blurred dose distribution was analyzed; PTV coverage was required to be at least V{sub 95%} >98%. In addition, the change in PTV size and the changes in V{sub 10Gy}, V{sub 20Gy}, V{sub 30Gy}, V{sub 40Gy}, D{sub mean} and D{sub 2cc} for the stomach and for the duodenum were analyzed; differences were tested for significance using the Wilcoxon signed-rank test. Results: Using a midV approach resulted in sufficient target coverage. A highly significant PTV size reduction of 13.9% (P<.001) was observed. Also, all dose parameters for the stomach and duodenum, except the D{sub 2cc} of the duodenum, improved significantly (P≤.002). Conclusions: By using the midV approach to account for respiratory-induced tumor motion, a significant PTV reduction and significant dose reductions to the stomach and to the duodenum can be achieved when irradiating pancreatic tumors.

  8. Dosimetric Advantages of Midventilation Compared With Internal Target Volume for Radiation Therapy of Pancreatic Cancer

    International Nuclear Information System (INIS)

    Purpose: The midventilation (midV) approach can be used to take respiratory-induced pancreatic tumor motion into account during radiation therapy. In this study, the dosimetric consequences for organs at risk and tumor coverage of using a midV approach compared with using an internal target volume (ITV) were investigated. Methods and Materials: For each of the 18 patients, 2 treatment plans (25 × 2.0 Gy) were created, 1 using an ITV and 1 using a midV approach. The midV dose distribution was blurred using the respiratory-induced motion from 4-dimensional computed tomography. The resulting planning target volume (PTV) coverage for this blurred dose distribution was analyzed; PTV coverage was required to be at least V95% >98%. In addition, the change in PTV size and the changes in V10Gy, V20Gy, V30Gy, V40Gy, Dmean and D2cc for the stomach and for the duodenum were analyzed; differences were tested for significance using the Wilcoxon signed-rank test. Results: Using a midV approach resulted in sufficient target coverage. A highly significant PTV size reduction of 13.9% (P<.001) was observed. Also, all dose parameters for the stomach and duodenum, except the D2cc of the duodenum, improved significantly (P≤.002). Conclusions: By using the midV approach to account for respiratory-induced tumor motion, a significant PTV reduction and significant dose reductions to the stomach and to the duodenum can be achieved when irradiating pancreatic tumors

  9. An analytic solution for calculating the beam intensity profiles useful to irradiate target volumes with bi-concave outlines

    International Nuclear Information System (INIS)

    A heuristic planing procedure allowing to obtain a 3-dimensional conformal dose distribution in radiotherapy for target volumes with a bi-concave or multi-concave shape has been developed. The described method is tested on a phantom simulating a pelvic target, described by Brahme

  10. An analytic solution for calculating the beam intensity profiles useful to irradiate target volumes with bi-concave outlines

    Energy Technology Data Exchange (ETDEWEB)

    De Neve, W.; Derycke, S.; De Wagter, C. [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde

    1995-12-01

    A heuristic planing procedure allowing to obtain a 3-dimensional conformal dose distribution in radiotherapy for target volumes with a bi-concave or multi-concave shape has been developed. The described method is tested on a phantom simulating a pelvic target, described by Brahme.

  11. Anatomo-clinical target volumes (GTV and CTV) in radiotherapy; Volumes cibles anatomocliniques (GTV et CTV) en radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Kantor, G. [Institut Bergonie, Universite Victor-Segalen, Dept. de Radiotherapie, Centre Regional de Lutte Contre le Cancer, 33 - Bordeaux (France); Halimi, P. [Hopital Europeen Georges-Pompidou, Service de Radiologie, Faculte de Medecine Paris-5, 75 - Paris (France)

    2005-06-15

    In this issue will be tackled the development of tools (multi modules scanner and images fusion) and the analysis of volumes for cerebral tumors (head and neck). It seemed necessary to update this theme because of the ever more widespread use of conformation radiotherapy and new constraints of volumes definitions brought by radiotherapy with intensity modulation. (N.C.)

  12. Target volumes in radiotherapy for high-grade malignant glioma of the brain

    International Nuclear Information System (INIS)

    Delineation of the clinical target volume (CTV) in radiation treatment planning of high-grade glioma is a controversial issue. The use of computerized tomography (CT) and magnetic resonance imaging (MRI) has greatly improved the accuracy of tumor localization in three-dimensional planning. This review aims at critically analyzing available literature data in which tumor extent of high-grade glioma has been assessed using CT and/or MRI and relating this to postmortem observations. Attention is given to the pattern of tumor spread at initial presentation and to tumor recurrence pattern after external beam irradiation. Special emphasis is given to the site of tumor regrowth after radiation treatment in relation to the boundaries of the CTV. Guidelines for delineating CTV will be inferred from this information, taking data on radiation effects on the normal brain into account. (author)

  13. Evaluation of potential internal target volume of liver tumors using cine-MRI

    International Nuclear Information System (INIS)

    Purpose: Four-dimensional computed tomography (4DCT) is widely used for evaluating moving tumors, including lung and liver cancers. For patients with unstable respiration, however, the 4DCT may not visualize tumor motion properly. High-speed magnetic resonance imaging (MRI) sequences (cine-MRI) permit direct visualization of respiratory motion of liver tumors without considering radiation dose exposure to patients. Here, the authors demonstrated a technique for evaluating internal target volume (ITV) with consideration of respiratory variation using cine-MRI. Methods: The authors retrospectively evaluated six patients who received stereotactic body radiotherapy (SBRT) to hepatocellular carcinoma. Before acquiring planning CT, sagittal and coronal cine-MRI images were acquired for 30 s with a frame rate of 2 frames/s. The patient immobilization was conducted under the same condition as SBRT. Planning CT images were then acquired within 15 min from cine-MRI image acquisitions, followed by a 4DCT scan. To calculate tumor motion, the motion vectors between two continuous frames of cine-MRI images were calculated for each frame using the pyramidal Lucas–Kanade method. The target contour was delineated on one frame, and each vertex of the contour was shifted and copied onto the following frame using neighboring motion vectors. 3D trajectory data were generated with the centroid of the contours on sagittal and coronal images. To evaluate the accuracy of the tracking method, the motion of clearly visible blood vessel was analyzed with the motion tracking and manual detection techniques. The target volume delineated on the 50% (end-exhale) phase of 4DCT was translated with the trajectory data, and the distribution of the occupancy probability of target volume was calculated as potential ITV (ITV Potential). The concordance between ITV Potential and ITV estimated with 4DCT (ITV 4DCT) was evaluated using the Dice’s similarity coefficient (DSC). Results: The distance

  14. Role of choline PET/CT in guiding target volume delineation for irradiation of prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Schwarzenboeck, S.M.; Kurth, J. [University Medical Centre Rostock, Department of Nuclear Medicine, Rostock (Germany); Gocke, C.; Kuhnt, T.; Hildebrandt, G. [University Medical Centre Rostock, Department of Radiotherapy, Rostock (Germany); Krause, B.J. [University Medical Centre Rostock, Department of Nuclear Medicine, Rostock (Germany); Universitaet Rostock, Department of Nuclear Medicine, Universitaetsmedizin Rostock, Rostock (Germany)

    2013-07-15

    Choline PET/CT has shown limitations for the detection of primary prostate cancer and nodal metastatic disease, mainly due to limited sensitivity and specificity. Conversely in the restaging of prostate cancer recurrence, choline PET/CT is a promising imaging modality for the detection of local regional and nodal recurrence with an impact on therapy management. This review highlights current literature on choline PET/CT for radiation treatment planning in primary and recurrent prostate cancer. Due to limited sensitivity and specificity in differentiating between benign and malignant prostatic tissues in primary prostate cancer, there is little enthusiasm for target volume delineation based on choline PET/CT. Irradiation planning for the treatment of single lymph node metastases on the basis of choline PET/CT is controversial due to its limited lesion-based sensitivity in primary nodal staging. In high-risk prostate cancer, choline PET/CT might diagnose lymph node metastases, which potentially can be included in the conventional irradiation field. Prior to radiation treatment of recurrent prostate cancer, choline PET/CT may prove useful for patient stratification by excluding distant disease which would require systemic therapy. In patients with local recurrence, choline PET/CT can be used to delineate local sites of recurrence within the prostatic resection bed allowing a boost to PET-positive sites. In patients with lymph node metastases outside the prostatic fossa and regional metastatic lymph nodes, choline PET/CT might influence radiation treatment planning by enabling extension of the target volume to lymphatic drainage sites with or without a boost to PET-positive lymph nodes. Further clinical randomized trials are required to assess treatment outcomes following choline-based biological radiation treatment planning in comparison with conventional radiation treatment planning. (orig.)

  15. Change of tumor target volume during waiting time for intensity-modulated radiotherapy (IMRT) in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Objective: To determine the influence of change in tumor target volume of nasopharyngeal carcinoma (NPC) while waiting for intensity modulated radiation therapy (IMRT). Methods: From March 2005 to December 2005, 31 patients with nasopharyngeal carcinoma received IMRT as the initial treatment at the Cancer Hospital of Chinese Academic of Medical Sciences. The original simulation CT scan was acquired before IMRT planning. A second CT scan was acquired before the start of radiotherapy. Wait- ing time was defined as the duration between CT simulation and start of radiotherapy. CT-CT fusion was used to minimize the error of delineation between the first tumor target volume (GTV) and the second tumor target volume (sGTV). Tumor target volume was calculated by treatment planning system. T test was carried out to analyse the difference between GTV and sGTV. Pearson correlation and multivariate linear regression was used to analyse the influence factor of the change betweent GTV and sGTV. Results: Median waiting time was 18 days (range, 9-27 days). There were significant differences between GTV and sGTV of both primary tumor (P=0.009) and metastatic lymphoma (P=0.005 ). Both Pearson correlation and multivariate linear regression showed that the change of primary tumor target volume had significant correlation with the first tumor target volume but had no significant correlation with the waiting time, sex, age, T stage and N stage (1992 Chinese Fuzhou Staging Classification). Conclusions: Within the range of the waiting time ob- served in our study, large volume primary tumor would have had a significant increase in volume, but whether the therapeutic effect would be influenced or not would need to be proved by study of large number of cases. Patients with large volume tumor should be considered to reduce the influence of waiting time by enlarging gross target volume and clinical targe volume and by neoadjuveant chemotherapy. For avoiding the unnecessary high-dose to normal

  16. Radiotherapy planning for glioblastoma based on a tumor growth model: improving target volume delineation

    Science.gov (United States)

    Unkelbach, Jan; Menze, Bjoern H.; Konukoglu, Ender; Dittmann, Florian; Le, Matthieu; Ayache, Nicholas; Shih, Helen A.

    2014-02-01

    Glioblastoma differ from many other tumors in the sense that they grow infiltratively into the brain tissue instead of forming a solid tumor mass with a defined boundary. Only the part of the tumor with high tumor cell density can be localized through imaging directly. In contrast, brain tissue infiltrated by tumor cells at low density appears normal on current imaging modalities. In current clinical practice, a uniform margin, typically two centimeters, is applied to account for microscopic spread of disease that is not directly assessable through imaging. The current treatment planning procedure can potentially be improved by accounting for the anisotropy of tumor growth, which arises from different factors: anatomical barriers such as the falx cerebri represent boundaries for migrating tumor cells. In addition, tumor cells primarily spread in white matter and infiltrate gray matter at lower rate. We investigate the use of a phenomenological tumor growth model for treatment planning. The model is based on the Fisher-Kolmogorov equation, which formalizes these growth characteristics and estimates the spatial distribution of tumor cells in normal appearing regions of the brain. The target volume for radiotherapy planning can be defined as an isoline of the simulated tumor cell density. This paper analyzes the model with respect to implications for target volume definition and identifies its most critical components. A retrospective study involving ten glioblastoma patients treated at our institution has been performed. To illustrate the main findings of the study, a detailed case study is presented for a glioblastoma located close to the falx. In this situation, the falx represents a boundary for migrating tumor cells, whereas the corpus callosum provides a route for the tumor to spread to the contralateral hemisphere. We further discuss the sensitivity of the model with respect to the input parameters. Correct segmentation of the brain appears to be the most

  17. Radiotherapy planning for glioblastoma based on a tumor growth model: improving target volume delineation

    International Nuclear Information System (INIS)

    Glioblastoma differ from many other tumors in the sense that they grow infiltratively into the brain tissue instead of forming a solid tumor mass with a defined boundary. Only the part of the tumor with high tumor cell density can be localized through imaging directly. In contrast, brain tissue infiltrated by tumor cells at low density appears normal on current imaging modalities. In current clinical practice, a uniform margin, typically two centimeters, is applied to account for microscopic spread of disease that is not directly assessable through imaging. The current treatment planning procedure can potentially be improved by accounting for the anisotropy of tumor growth, which arises from different factors: anatomical barriers such as the falx cerebri represent boundaries for migrating tumor cells. In addition, tumor cells primarily spread in white matter and infiltrate gray matter at lower rate. We investigate the use of a phenomenological tumor growth model for treatment planning. The model is based on the Fisher–Kolmogorov equation, which formalizes these growth characteristics and estimates the spatial distribution of tumor cells in normal appearing regions of the brain. The target volume for radiotherapy planning can be defined as an isoline of the simulated tumor cell density. This paper analyzes the model with respect to implications for target volume definition and identifies its most critical components. A retrospective study involving ten glioblastoma patients treated at our institution has been performed. To illustrate the main findings of the study, a detailed case study is presented for a glioblastoma located close to the falx. In this situation, the falx represents a boundary for migrating tumor cells, whereas the corpus callosum provides a route for the tumor to spread to the contralateral hemisphere. We further discuss the sensitivity of the model with respect to the input parameters. Correct segmentation of the brain appears to be the most

  18. Radiotherapy planning for glioblastoma based on a tumor growth model: improving target volume delineation.

    Science.gov (United States)

    Unkelbach, Jan; Menze, Bjoern H; Konukoglu, Ender; Dittmann, Florian; Le, Matthieu; Ayache, Nicholas; Shih, Helen A

    2014-02-01

    Glioblastoma differ from many other tumors in the sense that they grow infiltratively into the brain tissue instead of forming a solid tumor mass with a defined boundary. Only the part of the tumor with high tumor cell density can be localized through imaging directly. In contrast, brain tissue infiltrated by tumor cells at low density appears normal on current imaging modalities. In current clinical practice, a uniform margin, typically two centimeters, is applied to account for microscopic spread of disease that is not directly assessable through imaging. The current treatment planning procedure can potentially be improved by accounting for the anisotropy of tumor growth, which arises from different factors: anatomical barriers such as the falx cerebri represent boundaries for migrating tumor cells. In addition, tumor cells primarily spread in white matter and infiltrate gray matter at lower rate. We investigate the use of a phenomenological tumor growth model for treatment planning. The model is based on the Fisher-Kolmogorov equation, which formalizes these growth characteristics and estimates the spatial distribution of tumor cells in normal appearing regions of the brain. The target volume for radiotherapy planning can be defined as an isoline of the simulated tumor cell density. This paper analyzes the model with respect to implications for target volume definition and identifies its most critical components. A retrospective study involving ten glioblastoma patients treated at our institution has been performed. To illustrate the main findings of the study, a detailed case study is presented for a glioblastoma located close to the falx. In this situation, the falx represents a boundary for migrating tumor cells, whereas the corpus callosum provides a route for the tumor to spread to the contralateral hemisphere. We further discuss the sensitivity of the model with respect to the input parameters. Correct segmentation of the brain appears to be the most

  19. Volume Transmission in Central Dopamine and Noradrenaline Neurons and Its Astroglial Targets.

    Science.gov (United States)

    Fuxe, Kjell; Agnati, Luigi F; Marcoli, Manuela; Borroto-Escuela, Dasiel O

    2015-12-01

    Already in the 1960s the architecture and pharmacology of the brainstem dopamine (DA) and noradrenaline (NA) neurons with formation of vast numbers of DA and NA terminal plexa of the central nervous system (CNS) indicated that they may not only communicate via synaptic transmission. In the 1980s the theory of volume transmission (VT) was introduced as a major communication together with synaptic transmission in the CNS. VT is an extracellular and cerebrospinal fluid transmission of chemical signals like transmitters, modulators etc. moving along energy gradients making diffusion and flow of VT signals possible. VT interacts with synaptic transmission mainly through direct receptor-receptor interactions in synaptic and extrasynaptic heteroreceptor complexes and their signaling cascades. The DA and NA neurons are specialized for extrasynaptic VT at the soma-dendrtitic and terminal level. The catecholamines released target multiple DA and adrenergic subtypes on nerve cells, astroglia and microglia which are the major cell components of the trophic units building up the neural-glial networks of the CNS. DA and NA VT can modulate not only the strength of synaptic transmission but also the VT signaling of the astroglia and microglia of high relevance for neuron-glia interactions. The catecholamine VT targeting astroglia can modulate the fundamental functions of astroglia observed in neuroenergetics, in the Glymphatic system, in the central renin-angiotensin system and in the production of long-distance calcium waves. Also the astrocytic and microglial DA and adrenergic receptor subtypes mediating DA and NA VT can be significant drug targets in neurological and psychiatric disease. PMID:25894681

  20. Gross tumor volume (GTV) and clinical target volume (CTV) for radiation therapy of benign skull base tumours; Volume tumoral macroscopique (GTV) et volume-cible anatomoclinique (CTV) dans la radiotherapie des tumeurs benignes de la base du crane

    Energy Technology Data Exchange (ETDEWEB)

    Maire, J.P. [Centre Hospitalier Universitaire de Bordeaux, Hopital Saint Andre, Service d' Oncologie Radiotherapie, 33 - Bordeaux (France); Liguoro, D.; San Galli, F. [Centre Hospitalier Universitaire de Bordeaux, Hopital Saint Andre, Service de Neurochirurgie A, 33 - Bordeaux (France)

    2001-10-01

    Skull base tumours represent a out 35 to 40% of all intracranial tumours. There are now many reports in the literature confirming the fact that about 80 to 90% of such tumours are controlled with fractionated radiotherapy. Stereotactic and 3-dimensional treatment planning techniques increase local control and central nervous system tolerance. Definition of the gross tumor volume (GTV) is generally easy with currently available medical imaging systems and computers for 3-dimensional dosimetry. The definition of the clinical target volume (CTV) is more difficult to appreciate: it is defined from the CTV plus a margin, which depends on the histology and anterior therapeutic history of the tumour. It is important to take into account the visible tumour and its possible extension pathways (adjacent bone, holes at the base of skull) and/or an anatomic region (sella turcica + adjacent cavernous sinus). It is necessary to evaluate these volumes with CT Scan and MRI to appreciate tumor extension in a 3-dimensional approach, in order to reduce the risk of marginal recurrences. The aim of this paper is to discuss volume definition as a function of tumour site and tumour type to be irradiated. (authors)

  1. Radiotherapy of large target volumes in Hodgkin's lymphoma: normal tissue sparing capability of forward IMRT versus conventional techniques

    OpenAIRE

    Conson Manuel; Magliulo Mario; Liuzzi Raffaele; Cella Laura; Camera Luigi; Salvatore Marco; Pacelli Roberto

    2010-01-01

    Abstract Background This paper analyses normal tissue sparing capability of radiation treatment techniques in Hodgkin's lymphoma with large treatment volume. Methods 10 patients with supradiaphragmatic Hodgkin's lymphoma and planning target volume (PTV) larger than 900 cm3 were evaluated. Two plans were simulated for each patient using 6 MV X-rays: a conventional multi-leaf (MLC) parallel-opposed (AP-PA) plan, and the same plan with additional MLC shaped segments (forward planned intensity mo...

  2. Definition of the planning target volume of organs at risk (planning organ at risk volume, PRV) in case of radiotherapy of the ORL sphere

    International Nuclear Information System (INIS)

    The authors report a study which aimed at quantifying anatomic variations of organs at risk and their dosimetric impact, and at computing appropriate margins around organs at risk to generate planning target volumes of organs at risk, representative of the dose delivered to organs at risk. Nine patients have been treated for a locally advanced ORL cancer by a concomitant combination of radiotherapy and chemotherapy, with weekly scanographies during the radiotherapy. Registration has been successfully performed according to three bone references. Volume modifications and motions have been computed to define the margins around three organs at risk. Short communication

  3. Integrating respiratory-gated PET-based target volume delineation in liver SBRT planning, a pilot study

    International Nuclear Information System (INIS)

    To assess the feasibility and benefit of integrating four-dimensional (4D) Positron Emission Tomography (PET) – computed tomography (CT) for liver stereotactic body radiation therapy (SBRT) planning. 8 patients with 14 metastases were accrued in the study. They all underwent a non-gated PET and a 4D PET centered on the liver. The same CT scan was used for attenuation correction, registration, and considered the planning CT for SBRT planning. Six PET phases were reconstructed for each 4D PET. By applying an individualized threshold to the 4D PET, a Biological Internal Target Volume (BITV) was generated for each lesion. A gated Planning Target Volume (PTVg) was created by adding 3 mm to account for set-up margins. This volume was compared to a manual Planning Target Volume (PTV) delineated with the help of a semi-automatic Biological Target Volume (BTV) obtained from the non-gated exam. A 5 mm radial and a 10 mm craniocaudal margins were applied to account for tumor motion and set-up margins to create the PTV. One undiagnosed liver metastasis was discovered thanks to the 4D PET. The semi-automatic BTV were significantly smaller than the BITV (p = 0.0031). However, after applying adapted margins, 4D PET allowed a statistically significant decrease in the PTVg as compared to the PTV (p = 0.0052). In comparison to non-gated PET, 4D PET may better define the respiratory movements of liver targets and improve SBRT planning for liver metastases. Furthermore, non respiratory-gated PET exams can both misdiagnose liver metastases and underestimate the real internal target volumes

  4. Optimization of radiotherapy to target volumes with concave outlines: target-dose homogenization and selective sparing of critical structures by constrained matrix inversion

    International Nuclear Information System (INIS)

    The design of 3D-conformal dose distributions for targets with concave outlines is a technical challenge in conformal radiotherapy. For these targets, it is impossible to find beam incidences for which the target volume can be isolated from the tissues at risk. Commonly occurring examples are most thyroid cancers and the targets located at the lower neck and upper mediastinal levels related to some head and neck. A solution to this problem was developed, using beam intensity modulation executed with a multileaf collimator by applying a static beam-segmentation technique. The method includes the definition of beam incidences and beam segments of specific shape as well as the calculation of segment weights. Tests on Sherouse's GRATISTM planning system allowed to escalate the dose to these targets to 65-70 Gy without exceeding spinal cord tolerance. Further optimization by constrained matrix inversion was investigated to explore the possibility of further dose escalation

  5. Optimization of radiotherapy to target volumes with concave outlines: target-dose homogenization and selective sparing of critical structures by constrained matrix inversion

    Energy Technology Data Exchange (ETDEWEB)

    Colle, C.; Van den Berge, D.; De Wagter, C.; Fortan, L.; Van Duyse, B.; De Neve, W.

    1995-12-01

    The design of 3D-conformal dose distributions for targets with concave outlines is a technical challenge in conformal radiotherapy. For these targets, it is impossible to find beam incidences for which the target volume can be isolated from the tissues at risk. Commonly occurring examples are most thyroid cancers and the targets located at the lower neck and upper mediastinal levels related to some head and neck. A solution to this problem was developed, using beam intensity modulation executed with a multileaf collimator by applying a static beam-segmentation technique. The method includes the definition of beam incidences and beam segments of specific shape as well as the calculation of segment weights. Tests on Sherouse`s GRATISTM planning system allowed to escalate the dose to these targets to 65-70 Gy without exceeding spinal cord tolerance. Further optimization by constrained matrix inversion was investigated to explore the possibility of further dose escalation.

  6. Target volume delineation and field setup. A practical guide for conformal and intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Nancy Y. [Memorial Sloan-Kettering Cancer Center, New York, NY (United States). Radiation Oncology; Lu, Jiade J. (eds.) [National Univ. Health System, Singapore (Singapore). Dept. of Radiation Oncology; National Univ. of Singapore (Singapore). Dept. of Medicine

    2013-03-01

    Practical handbook on selection and delineation of tumor volumes and fields for conformal radiation therapy, including IMRT. Helpful format facilitating use on a step-by-step basis in daily practice. Designed to ensure accurate coverage of commonly encountered tumors along their routes of spread. This handbook is designed to enable radiation oncologists to appropriately and confidently delineate tumor volumes/fields for conformal radiation therapy, including intensity-modulated radiation therapy (IMRT), in patients with commonly encountered cancers. The orientation of this handbook is entirely practical, in that the focus is on the illustration of clinical target volume (CTV) delineation for each major malignancy. Each chapter provides guidelines and concise knowledge on CTV selection for a particular disease, explains how the anatomy of lymphatic drainage shapes the selection of the target volume, and presents detailed illustrations of volumes, slice by slice, on planning CT images. While the emphasis is on target volume delineation for three-dimensional conformal therapy and IMRT, information is also provided on conventional radiation therapy field setup and planning for certain malignancies for which IMRT is not currently suitable.

  7. Anatomic Boundaries of the Clinical Target Volume (Prostate Bed) After Radical Prostatectomy

    International Nuclear Information System (INIS)

    Purpose: We sought to derive and validate an interdisciplinary consensus definition for the anatomic boundaries of the postoperative clinical target volume (CTV, prostate bed). Methods and Materials: Thirty one patients who had planned for radiotherapy after radical prostatectomy were enrolled and underwent computed tomography and magnetic resonance imaging (MRI) simulation prior to radiotherapy. Through an iterative process of consultation and discussion, an interdisciplinary consensus definition was derived based on a review of published data, patterns of local failure, surgical practice, and radiologic anatomy. In validation, we analyzed the distribution of surgical clips in reference to the consensus CTV and measured spatial uncertainties in delineating the CTV and vesicourethral anastomosis. Clinical radiotherapy plans were retrospectively evaluated against the consensus CTV (prostate bed). Results: Anatomic boundaries of the consensus CTV (prostate bed) are described. Surgical clips (n = 339) were well distributed throughout the CTV. The vesicourethral anastomosis was accurately localized using central sagittal computed tomography reconstruction, with a mean ± standard deviation uncertainty of 1.8 ± 2.5 mm. Delineation uncertainties were small for both MRI and computed tomography (mean reproducibility, 0-3.8 mm; standard deviation, 1.0-2.3); they were most pronounced in the anteroposterior and superoinferior dimensions and at the superior/posterior-most aspect of the CTV. Retrospectively, the mean ± standard deviation CTV (prostate bed) percentage of volume receiving 100% of prescribed dose was only 77% ± 26%. Conclusions: We propose anatomic boundaries for the CTV (prostate bed) and present evidence supporting its validity. In the absence of gross recurrence, the role of MRI in delineating the CTV remains to be confirmed. The CTV is larger than historically practiced at our institution and should be encompassed by a microscopic tumoricidal dose

  8. Impact Factors for Microinvasion in Intrahepatic Cholangiocarcinoma: A Possible System for Defining Clinical Target Volume

    International Nuclear Information System (INIS)

    Purpose: To quantify microscopic invasion of intrahepatic cholangiocarcinoma (IHC) into nontumor tissue and define the gross tumor volume (GTV)-to-clinical target volume (CTV) expansion necessary for radiotherapy. Methods and Materials: One-hundred IHC patients undergoing radical resection from January 2004 to July 2008 were enrolled in this study. Pathologic and clinical data including maximum tumor diameter, tumor boundary type, TNM stage, histologic grade, tumor markers, and liver enzymes were reviewed. The distance of microinvasion from the tumor boundary was measured by microscopy. The contraction coefficient for tumor measurements in radiographs and slide-mounted tissue was calculated. SPSS15.0 was used for statistical analysis. Results: Sixty-five patients (65%) exhibited tumor microinvasions. Microinvasions ranged from 0.4-8 mm, with 96% of patients having a microinvasion distance ≤6 mm measured on slide. The radiograph-to-slide contraction coefficient was 82.1%. The degree of microinvasion was correlated with tumor boundary type, TNM stage, histologic grade, and serum levels of carbohydrate antigen 19-9, alanine aminotransferase, aspartate aminotransferase, γ-glutamyltransferase and alkaline phosphatase. To define CTV accurately, we devised a scoring system based on combination of these factors. According to this system, a score ≤1.5 is associated with 96.1% sensitivity in detecting patients with a microextension ≤4.9 mm in radiographs, whereas a score ≥2 has a 95.1% sensitivity in detecting microextension ≤7.9 mm measured on radiograph. Conclusions: Patients with a score ≤1.5 and ≥2 require a radiographic GTV-to-CTV expansions of 4.9 and 7.9 mm, respectively, to encompass >95% of microinvasions.

  9. Microinvasion of liver metastases from colorectal cancer: predictive factors and application for determining clinical target volume

    International Nuclear Information System (INIS)

    This study evaluates the microscopic characteristics of liver metastases from colorectal cancer (LMCRC) invasion and provides a reference for expansion from gross tumor volume (GTV) to clinical targeting volume (CTV). Data from 129 LMCRC patients treated by surgical resection at our hospital between January 2008 and September 2009 were collected for study. Tissue sections used for pathology and clinical data were reviewed. Patient information used for the study included gender, age, original tumor site, number of tumors, tumor size, levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 199 (CA199), synchronous or metachronous liver metastases, and whether patients received chemotherapy. The distance of liver microinvasion from the tumor boundary was measured microscopically by two senior pathologists. Of 129 patients evaluated, 81 (62.8 %) presented microinvasion distances from the tumor boundary ranging between 1.0 − 7.0 mm. A GTV-to-CTV expansion of 5, 6.7, or 7.0 mm was required to provide a 95, 99, or 100 % probability, respectively, of obtaining clear resection margins by microscopic observation. The extent of invasion was not related to gender, age, synchronous or metachronous liver metastases, tumor size, CA199 level, or chemotherapy. The extent of invasion was related to original tumor site, CEA level, and number of tumors. A scoring system was established based on the latter three positive predictors. Using this system, an invasion distance less than 3 mm was measured in 93.4 % of patients with a score of ≤1 point, but in only 85.7 % of patients with a score of ≤2 points. The extent of tumor invasion in our LMCRC patient cohort correlated with original tumor site, CEA level, and number of tumors. These positive predictors may potentially be used as a scoring system for determining GTV-to-CTV expansion

  10. Note: Development of a volume-limited dot target for a high brightness extreme ultraviolet microplasma source

    International Nuclear Information System (INIS)

    We report on production of volume-limited dot targets based on electron beam lithographic and sputtering technologies for use in efficient high brightness extreme ultraviolet microplasma sources. We successfully produced cylindrical tin (Sn) targets with diameters of 10, 15, and 20 μm and a height of 150 nm. The calculated spectrum around 13.5 nm was in good agreement with that obtained experimentally

  11. Delineation of target volumes and organs at risk in conformal radiotherapy for the prostate cancer: French trials of dose escalation

    International Nuclear Information System (INIS)

    The delineation of target volume and organs at risk depends on the organs definition, and on the modalities for the CT-scan acquisition. Inter-observer variability in the delineation may be large, especially when patient's anatomy is unusual. During the two french multicentric studies of conformal radiotherapy for localized prostate cancer, it was made an effort to harmonize the delineation of the target volumes and organs at risk. Two cases were proposed for delineation during two workshops. In the first case, the mean prostate volume was 46,5 mL (extreme: 31,7-61,3), the mean prostate and seminal vesicles volume was 74,7 mL (extreme: 59,6-80,3), the rectal and bladder walls varied respectively in proportion from 1 to 1,45 and from 1 to 1,16; in the second case, the mean prostate volume was 53,1 mL (extreme: 40,8-73,1), the volume of prostate plus seminal vesicles was 65,1 mL (extreme: 53,2-89), the rectal wall varied proportionally from 1 to 1, 24 and the vesical wall varied from 1 to 1,67. For participating centers to the french studies of dose escalation, a quality control of contours was performed to decrease the inter-observer variability. The ways to reduce the discrepancies of volumes delineation, between different observers, are discussed. A better quality of the CT images use of urethral opacification, and consensual definition of clinical target volumes and organs at risk may contribute to that improvement. (authors)

  12. Gross tumor volume and clinical target volume in prostate cancer: How do satellites relate to the index lesion

    International Nuclear Information System (INIS)

    Purpose: There is an increasing interest for dose differentiation in prostate radiotherapy. The purpose of our study was to analyze the spatial distribution of tumor satellites inside the prostate. Methods and materials: 61 prostatectomy specimens were stained with H&E. Tumor regions were delineated by the uro-pathologist. Volumes, distances and cell densities of all delineated tumor regions were measured and further analyzed. Results: Multifocal disease was seen in 84% of the patients. The median number of tumor foci was 3. The median distance between the index lesion and the satellites was 1.0 cm, with a maximum of 4.4 cm. The index lesions accounted for 88% of the total tumor volume. The contribution of tumor foci < 0.1 cm3 to the total tumor volume was 2%. The median cell density of the index lesion and all satellites, regardless of size, were significantly higher than that of the prostate. Conclusions: Satellites do not appear in a limited margin around the index lesion (GTV). Consequently, a fixed CTV margin would not effectively cover all satellites. Thus if the aim is to treat all tumor foci, the entire prostate gland should be considered CTV

  13. The ADVANCE project: Formal evaluation of the targeted deployment. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    The Advanced Driver and Vehicle Advisory Navigation ConcEpt (ADVANCE) was an invehicle advanced traveler information system (ATIS) that operated in the northwest suburbs of Chicago, Illinois. It was designed to provide origin-destination shortest-time route guidance to a vehicle based on (a) an on-board static (fixed) data base of average network link travel times by time of day, combined as available and appropriate with (b) dynamic (real-time) information on traffic conditions provided by radio frequency (RF) communications to and from a traffic information center (TIC). Originally conceived in 1990 as a major project that would have installed 3,000 to 5,000 route guidance units in privately owned vehicles throughout the test area, ADVANCE was restructured in 1995 as a {open_quotes}targeted deployment,{close_quotes} in which approximately 80 vehicles were to be equipped with the guidance units - Mobile Navigation Assistants (MNAs) - to be in full communication with the TIC while driving the ADVANCE test area road system. Volume one consists of the evaluation managers overview report, and several appendices containing test results.

  14. ESTRO consensus guideline on target volume delineation for elective radiation therapy of early stage breast cancer

    International Nuclear Information System (INIS)

    Background and purpose: Delineation of clinical target volumes (CTVs) is a weak link in radiation therapy (RT), and large inter-observer variation is seen in breast cancer patients. Several guidelines have been proposed, but most result in larger CTVs than based on conventional simulator-based RT. The aim was to develop a delineation guideline obtained by consensus between a broad European group of radiation oncologists. Material and methods: During ESTRO teaching courses on breast cancer, teachers sought consensus on delineation of CTV through dialogue based on cases. One teacher delineated CTV on CT scans of 2 patients, followed by discussion and adaptation of the delineation. The consensus established between teachers was sent to other teams working in the same field, both locally and on a national level, for their input. This was followed by developing a broad consensus based on discussions. Results: Borders of the CTV encompassing a 5 mm margin around the large veins, running through the regional lymph node levels were agreed, and for the breast/thoracic wall other vessels were pointed out to guide delineation, with comments on margins for patients with advanced breast cancer. Conclusion: The ESTRO consensus on CTV for elective RT of breast cancer, endorsed by a broad base of the radiation oncology community, is presented to improve consistency

  15. Clinical target volume delineation including elective nodal irradiation in preoperative and definitive radiotherapy of pancreatic cancer

    International Nuclear Information System (INIS)

    Radiotherapy (RT) is widely used in the treatment of pancreatic cancer. Currently, recommendation has been given for the delineation of the clinical target volume (CTV) in adjuvant RT. Based on recently reviewed pathologic data, the aim of this study is to propose criteria for the CTV definition and delineation including elective nodal irradiation (ENI) in the preoperative and definitive treatment of pancreatic cancer. The anatomical structures of interest, as well as the abdominal vasculature were identified on intravenous contrast-enhanced CT scans of two different patients with pancreatic cancer of the head and the body. To delineate the lymph node area, a margin of 10 mm was added to the arteries. We proposed a set of guidelines for elective treatment of high-risk nodal areas and CTV delineation. Reference CT images were provided. The proposed guidelines could be used for preoperative or definitive RT for carcinoma of the head and body of the pancreas. Further clinical investigations are needed to validate the defined CTVs

  16. Uncertainties of target volume delineation in MRI guided adaptive brachytherapy of cervix cancer: A multi-institutional study

    International Nuclear Information System (INIS)

    Background and aim: We aimed to quantify target volume delineation uncertainties in cervix cancer image guided adaptive brachytherapy (IGABT). Materials and methods: Ten radiation oncologists delineated gross tumour volume (GTV), high- and intermediate-risk clinical target volume (HR CTV, IR CTV) in six patients. Their contours were compared with two reference delineations (STAPLE-Simultaneous Truth and Performance Level Estimation and EC- expert consensus) by calculating volumetric and planar conformity index (VCI and PCI) and inter-delineation distances (IDD). Results: VCISTAPLE and VCIEC were 0.76 and 0.72 for HR CTV, 0.77 and 0.68 for IR CTV and 0.59 and 0.58 for GTV. Variation was most prominent caudally and cranially in all target volumes and posterolaterally in IR CTV. IDDSTAPLE and IDDEC for HR CTV (3.6 ± 3.5 and 3.8 ± 3.4 mm) were significantly lower than for GTV (4.8 ± 4.2 and 4.2 ± 3.5 mm) and IR CTV (4.7 ± 5.2 and 5.2 ± 5.6 mm) (p < 0.05). Conclusions: Due to lower delineation uncertainties when compared to GTV and IR CTV, HR CTV may be considered most robust volume for dose prescription and optimization in cervix cancer IGABT. Adequate imaging, training and use of contouring recommendations are main strategies to minimize delineation uncertainties

  17. Patterns of relapse following radiotherapy for differentiated thyroid cancer: Implication for target volume delineation

    International Nuclear Information System (INIS)

    Introduction: Post-operative residual disease in differentiated thyroid cancer is an indication for external beam radiotherapy (EBRT) especially if there is poor radioiodine uptake by the residual disease. There are no standardized guidelines or consensus in target delineation for radiotherapy in thyroid cancer. Aims: To determine the pattern of recurrence in patients with well differentiated thyroid cancer who received adjuvant or definitive radiotherapy as well as radioiodine ablation following surgery or biopsy with a view to better defining future target volume delineation for radiotherapy. Materials and methods: Forty-nine patients with differentiated thyroid cancer received radical external beam radiotherapy and radioiodine ablation (3.5 GBq) following thyroidectomy or biopsy between 1990 and 2000. Nineteen patients had macroscopic residual (11) or inoperable disease (8), whilst 30 patients had clear (5) or microscopic positive resection margin (24), and 1 patient the resection margin status was unknown. All the patients were deemed high risk for local recurrence or progressive disease. The thyroid bed and regional nodes were irradiated using two radiotherapy techniques: (1) non co-planar lateral fields (NCLF) in coronal plane using 6 MV photons to a dose of 45-50 Gy in 16 fractions over 22 days and (2) anterior-posterior parallel pair of 6 MV photons to a dose of 40-42.5 Gy in 16 fractions over 22 days. There was no attempt to irradiate the lymph nodes in that part of the anterior and posterior mediastinum extending from the brachiocephalic veins to the carina. Results: The median follow-up was 5.4 years (range 0.9-12.4 years). The actuarial 5-year cause-specific survival and local control for the whole group was 75.7% and 81.4%, respectively. Of the 4 patients with mediastinal recurrence, all had neck recurrences and two had distant metastases. All the medisastinal recurrences occurred in superior mediastinum (level VII) and all were treated with NCLF in

  18. Analysis of FET-PET imaging for target volume definition in patients with gliomas treated with conformal radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: Modern radiotherapy (RT) techniques such as stereotactic RT, intensity-modulated RT, or particle irradiation allow local dose escalation with simultaneous sparing of critical organs. Several trials are currently investigating their benefit in glioma reirradiation and boost irradiation. Target volume definition is of critical importance especially when steep dose gradient techniques are employed. In this manuscript we investigate the impact of O-(2-(F-18)fluoroethyl)-L-tyrosine-positron emission tomography/computer tomography (FET-PET/CT) on target volume definition in low and high grade glioma patients undergoing either first or re-irradiation with particles. Methods and material: We investigated volumetric size and uniformity of magnetic resonance imaging (MRI)- vs. FET-PET/CT-derived gross tumor volumes (GTVs) and planning target volumes (PTVs) of 41 glioma patients. Clinical cases are presented to demonstrate potential benefits of integrating FET-PET/CT-planning into daily routine. Results: Integrating FET-uptake into the delineation of GTVs yields larger volumes. Combined modality-derived PTVs are significantly enlarged in high grade glioma patients and in case of primary RT. The congruence of MRI and FET signals for the identification of glioma GTVs is poor with mean uniformity indices of 0.39. MRI-based PTVs miss 17% of FET-PET/CT-based GTVs. Non significant alterations were detected in low grade glioma patients and in those undergoing reirradiation. Conclusions: Target volume definition for malignant gliomas during initial RT may yield significantly differing results depending upon the imaging modality, which the contouring process is based upon. The integration of both MRI and FET-PET/CT may help to improve GTV coverage by avoiding larger incongruences between physical and biological imaging techniques. In low grade gliomas and in cases of reirradiation, more studies are needed in order to investigate a potential benefit of FET

  19. Locoregional extension patterns of nasopharyngeal carcinoma and suggestions for clinical target volume delineation

    Institute of Scientific and Technical Information of China (English)

    Wen-Fei Li; Jun Ma; Ying Sun; Mo Chen; Ling-Long Tang; Li-Zhi Liu; Yan-Ping Mao; Lei Chen; Guan-Qun Zhou; Li Li

    2012-01-01

    Clinical target volume (CTV) delineation is crucial for tumor control and normal tissue protection.This study aimed to define the Iocoregional extension patterns of nasopharyngeal carcinoma (NPC) and to improve CTV delineation.Magnetic resonance imaging scans of 2366 newly diagnosed NPC patients were reviewed.According to incidence rates of tumor invasion,the anatomic sites surrounding the nasopharynx were classified into high-risk (>30%),medium-risk (5%-30%),and low-risk (<5%) groups.The lymph node (LN) level was determined according to the Radiation Therapy Oncology Group guidelines,which were further categorized into the upper neck (retropharyngeal region and level Ⅱ),middle neck (levels Ⅲ and Va),and lower neck (levels IV and Vb and the supraclavicular fossa).The high-risk anatomic sites were adjacent to the nasopharynx,whereas those at medium-or low-risk were separated from the nasopharynx.If the high-risk anatomic sites were involved,the rates of tumor invasion into the adjacent medium-risk sites increased; if not,the rates were significantly lower (P < 0.01).Among the 1920 (81.1%) patients with positive LN,the incidence rates of LN metastasis in the upper,middle,and lower neck were 99.6%,30.2%,and 7.2%,respectively,and skip metastasis happened in only 1.2% of patients.In the 929 patients who had unilateral upper neck involvement,the rates of contralateral middle neck and lower neck involvement were 1.8% and 0.4%,respectively.Thus,local disease spreads stepwise from proximal sites to distal sites,and LN metastasis spreads from the upper neck to the lower neck.Individualized CTV delineation for NPC may be feasible.

  20. Impact of 18F-FDG PET/CT on target volume delineation in recurrent or residual gynaecologic carcinoma

    OpenAIRE

    Vees, Hansjoerg; Casanova, Nathalie; Zilli, Thomas; Imperiano, Hestia; Ratib, Osman; Popowski, Youri; Wang, Hui; Zaidi, Habib; Miralbell, Raymond

    2012-01-01

    Background To evaluate the impact of 18F-FDG PET/CT on target volume delineation in gynaecological cancer. Methods F-FDG PET/CT based RT treatment planning was performed in 10 patients with locally recurrent (n = 5) or post-surgical residual gynaecological cancer (n = 5). The gross tumor volume (GTV) was defined by 4 experienced radiation oncologists first using contrast enhanced CT (GTVCT) and secondly using the fused 18F-FDG PET/CT datasets (GTVPET/CT). In addition, the GTV was delineated u...

  1. The impact of Gross Tumor Volume (GTV) and Clinical Target Volume (CTV) definition on the total accuracy in radiotherapy. Theoretical aspects and practical experiences

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, E.; Hess, C.F. [Dept. of Radiation Therapy, Univ. of Goettingen (Germany)

    2003-01-01

    Aim: To evaluate the impact of interobserver variability in the contouring of gross tumor volumes (GTVs) and clinical target volumes (CTVs) on the global geometric accuracy in radiation therapy. Material and Methods: In a review of the currently available literature, the magnitude of interobserver variability is analyzed, causes and consequences are discussed. Uncertainties due to inconsistencies in contouring are related to other sources of geometric errors, particularly patient positioning and organ motion. Results: Interobserver variability is a major - for some tumor locations probably the largest - factor contributing to geometric inaccuracy. Causes are multifactorial and include image- and observer-related factors, such as the subjective interpretation of image information. Conclusion: Consequences to reduce interobserver variability are proposed, among others the selection of adequate imaging modalities, intensified radiologic training, and the use of telecommunication tools. (orig.)

  2. Variation in the Definition of Clinical Target Volumes for Pelvic Nodal Conformal Radiation Therapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Purpose: We conducted a comparative study of clinical target volume (CTV) definition of pelvic lymph nodes by multiple genitourinary (GU) radiation oncologists looking at the levels of discrepancies amongst this group. Methods and Materials: Pelvic computed tomography (CT) scans from 2 men were distributed to 14 Radiation Therapy Oncology Group GU radiation oncologists with instructions to define CTVs for the iliac and presacral lymph nodes. The CT data with contours were then returned for analysis. In addition, a questionnaire was completed that described the physicians' method for target volume definition. Results: Significant variation in the definition of the iliac and presacral CTVs was seen among the physicians. The minimum, maximum, mean (SD) iliac volumes (mL) were 81.8, 876.6, 337.6 ± 203 for case 1 and 60.3, 627.7, 251.8 ± 159.3 for case 2. The volume of 100% agreement was 30.6 and 17.4 for case 1 and 2 and the volume of the union of all contours was 1,012.0 and 807.4 for case 1 and 2, respectively. The overall agreement was judged to be moderate in both cases (kappa = 0.53 (p < 0.0001) and kappa = 0.48 (p < 0.0001). There was no volume of 100% agreement for either of the two presacral volumes. These variations were confirmed in the responses to the associated questionnaire. Conclusions: Significant disagreement exists in the definition of the CTV for pelvic nodal radiation therapy among GU radiation oncology specialists. A consensus needs to be developed so as to accurately assess the merit and safety of such treatment.

  3. Prospective comparative evaluation of planning target volume margin for brain intensity modulated radiotherapy utilizing hybrid online imaging modalities

    OpenAIRE

    Sayan Paul; Shilpi Roy; Shaleen Agrawal; Anusheel Munshi; Kanan Jassal; Tharmar Ganesh; Saneg Krishnankutty; Jeen Soundra Pandian Sathiya; Bidhu Kalyan Mohanti

    2015-01-01

    Background: A new advancement in daily monitoring of patient positioning is the use of hybrid technologies where two separate online imaging modalities are integrated to achieve precise treatment delivery. Our center has a set-up that integrates Elekta Linear accelerator device (EPID) with BrainLAB ExacTrac imaging for the first time in the world. We calculated planning target volume (PTV) margin for brain radiotherapy with thermoplastic mask immobilization with conventional EPID and BrainLAB...

  4. Atlas-based automatic segmentation of head and neck organs at risk and nodal target volumes: a clinical validation

    OpenAIRE

    Daisne, Jean-François; Blumhofer, Andreas

    2013-01-01

    Background Intensity modulated radiotherapy for head and neck cancer necessitates accurate definition of organs at risk (OAR) and clinical target volumes (CTV). This crucial step is time consuming and prone to inter- and intra-observer variations. Automatic segmentation by atlas deformable registration may help to reduce time and variations. We aim to test a new commercial atlas algorithm for automatic segmentation of OAR and CTV in both ideal and clinical conditions. Methods The updated Brai...

  5. Comparison of planning target volumes based on three-dimensional and four-dimensional CT imaging of thoracic esophageal cancer

    OpenAIRE

    Wang, Wei; LI, JIANBIN; Zhang, Yingjie; SHAO, QIAN; Xu, Min; Fan, Tingyong; Wang, Jinzhi

    2016-01-01

    Wei Wang, Jianbin Li, Yingjie Zhang, Qian Shao, Min Xu, Tingyong Fan, Jinzhi Wang Department of Radiation Oncology, Shandong Cancer Hospital Affiliated to Shandong University, Shandong Academy of Medical Sciences, Shandong, People’s Republic of China Background and purpose: To investigate the definition of planning target volumes (PTVs) based on four-dimensional computed tomography (4DCT) compared with conventional PTV definition and PTV definition using asymmetrical margins for t...

  6. Target volume definition for external beam partial breast radiotherapy: Clinical, pathological and technical studies informing current approaches

    International Nuclear Information System (INIS)

    Partial breast irradiation (PBI) is currently under investigation in several phase III trials and, following a recent consensus statement, its use off-study may increase despite ongoing uncertainty regarding optimal target volume definition. We review the clinical, pathological and technical evidence for target volume definition in external beam partial breast irradiation (EB-PBI). The optimal method of tumour bed (TB) delineation requires X-ray CT imaging of implanted excision cavity wall markers. The definition of clinical target volume (CTV) as TB plus concentric 15 mm margins is based on the anatomical distribution of multifocal and multicentric disease around the primary tumour in mastectomy specimens, and the clinical locations of local tumour relapse (LR) after breast conservation surgery. If the majority of LR originate from foci of residual invasive and/or intraduct disease in the vicinity of the TB after complete microscopic resection, CTV margin logically takes account of the position of primary tumour within the surgical resection specimen. The uncertain significance of independent primary tumours as sources of preventable LR, and of wound healing responses in stimulating LR, increases the difficulties in defining optimal CTV. These uncertainties may resolve after long-term follow-up of current PBI trials. By contrast, a commonly used 10 mm clinical to planning target volume (PTV) margin has a stronger evidence base, although departmental set-up errors need to be confirmed locally. A CTV-PTV margin >10 mm may be required in women with larger breasts and/or large seromas, whilst the role of image-guided radiotherapy with or without TB markers in reducing CTV-PTV margins needs to be explored.

  7. Target volume delineation in breast conserving radiotherapy: are co-registered CT and MR images of added value?

    International Nuclear Information System (INIS)

    In breast conserving radiotherapy differences of target volume delineations between observers do occur. We evaluated whether delineations based on co-registered computed tomography (CT) and magnetic resonance (MR) imaging may result in an improved consistency between observers. We used the delineation conformity index (CI) to compare clinical target volumes of glandular breast tissue (CTV breast) and lumpectomy cavity (LC) on both imaging modalities. Four observers delineated CTV breast and LC on co-registered CTMR images in ten breast cancer patients. CIs were determined for CT and CTMR. Furthermore, the Cavity Visualization Score (CVS) of LC was taken into account. The mean CI for CTV breast (CICT;CTV: 0.82 and CICT-CTMR;CTV: 0.80) and LC (CICT;LC: 0.52 and CICT-CTMR;LC: 0.48) did not differ significantly (p = 0.07 and p = 0.33, respectively). Taking CVS into account for the LC, with a CVS ≥ 4 the mean CI was 0.62 for both CICT;LC and CICT-CTMR;LC. The mean volume of the delineated glandular breast tissue based on CT was significantly larger compared to the volume based on CTMR. For patients with a CVS ≥ 4, the mean CIs of the LC were higher compared to CVS < 4 for volumes delineated on both CT as well as CTMR images. In our study cohort no significant differences between the CIs of the CTV breast and the LC delineated on CTMR co-registered images were found compared to the CIs on CT images only. Adding MR images does not seem to improve consistency of the delineation of the CTV breast and the LC, even though the volumes were copied from CT images. Since we included only ten patients, caution should be taken with regard to the results of our study

  8. Suggestion for the prostatic fossa clinical target volume in adjuvant or salvage radiotherapy after a radical prostatectomy

    International Nuclear Information System (INIS)

    Background and purpose: To assess the location of recurrent tumors and suggest the optimal target volume in adjuvant or salvage radiotherapy (RT) after a radical prostatectomy (RP). Material and methods: From January 2000 to December 2012, 113 patients had been diagnosed with suspected recurrent prostate cancer by MRI scan and received salvage RT in the Samsung Medical Center. This study assessed the location of the suspected tumor recurrences and used the inferior border of the pubic symphysis as a point of reference. Results: There were 118 suspect tumor recurrences. The most common site of recurrence was the anastomotic site (78.8%), followed by the bladder neck (15.3%) and retrovesical area (5.9%). In the cranial direction, 106 (87.3%) lesions were located within 30 mm of the reference point. In the caudal direction, 12 lesions (10.2%) were located below the reference point. In the transverse plane, 112 lesions (94.9%) were located within 10 mm of the midline. Conclusions: A MRI scan acquired before salvage RT is useful for the localization of recurrent tumors and the delineation of the target volume. We suggest the optimal target volume in adjuvant or salvage RT after RP, which includes 97% of suspected tumor recurrences

  9. Performance of an atlas-based autosegmentation software for delineation of target volumes for radiotherapy of breast and anorectal cancer

    International Nuclear Information System (INIS)

    Background and purpose: To validate atlas-based autosegmentation for contouring breast/anorectal targets. Methods and materials: ABAS uses atlases with defined CTVs as template cases to automatically delineate target volumes in other patient CT-datasets. Results are compared with manually contoured CTVs of breast/anorectal cancer according to RTOG-guidelines. The impact of using specific atlases matched to individual patient geometry was evaluated. Results were quantified by analyzing Dice Similarity Coefficient (DSC), logit(DSC) and Percent Overlap (PO). DSC >0.700 and logit(DSC) >0.847 are acceptable. In addition a new algorithm (STAPLE) was evaluated. Results: ABAS produced good results for the CTV of breast/anorectal cancer targets. Delineation of inguinal lymphatic drainage, however, was insufficient. Results for breast CTV were (DSC: 0.86–0.91 ([0, 1]), logit(DSC): 1.82–2.36 ([−∞, ∞]), PO: 75.5–82.89%) and for anorectal CTVA (DSC: 0.79–0.85, logit(DSC): 1.40–1.77, PO: 68–73.67%). Conclusions: ABAS produced satisfactory results for these clinical target volumes that are defined by more complex tissue interface geometry, thus streamlining and facilitating the radiotherapy workflow which is essential to face increasing demand and limited resources. STAPLE improved contouring outcome. Small target volumes not clearly defined are still to be delineated manually. Based on these results, ABAS has been clinically introduced for precontouring of CTVs/OARs.

  10. Changes in the planning target volume and liver volume dose based on the selected respiratory phase in respiratory-gated radiation therapy for a hepatocellular carcinoma

    Science.gov (United States)

    Lee, Jae-Seung; Im, In-Chul; Kang, Su-Man; Goo, Eun-Hoe; Baek, Seong-Min

    2013-11-01

    The aim of this study was to quantitatively analyze the changes in the planning target volume (PTV) and liver volume dose based on the respiratory phase to identify the optimal respiratory phase for respiratory-gated radiation therapy for a hepatocellular carcinoma (HCC). Based on the standardized procedure for respiratory-gated radiation therapy, we performed a 4-dimensional computed tomography simulation for 0 ˜ 90%, 30 ˜ 70%, and 40 ˜ 60% respiratory phases to assess the respiratory stability (S R ) and the defined PTV i for each respiratory phase i. A treatment plan was established, and the changes in the PTV i and dose volume of the liver were quantitatively analyzed. Most patients (91.5%) passed the respiratory stability test (S R = 0.111 ± 0.015). With standardized respiration training exercises, we were able to minimize the overall systematic error caused by irregular respiration. Furthermore, a quantitative analysis to identify the optimal respiratory phase revealed that when a short respiratory phase (40 ˜ 60%) was used, the changes in the PTV were concentrated inside the center line; thus, we were able to obtain both a PTV margin accounting for respiration and a uniform radiation dose within the PTV.

  11. Radiotherapy of large target volumes in Hodgkin's lymphoma: normal tissue sparing capability of forward IMRT versus conventional techniques

    Directory of Open Access Journals (Sweden)

    Conson Manuel

    2010-05-01

    Full Text Available Abstract Background This paper analyses normal tissue sparing capability of radiation treatment techniques in Hodgkin's lymphoma with large treatment volume. Methods 10 patients with supradiaphragmatic Hodgkin's lymphoma and planning target volume (PTV larger than 900 cm3 were evaluated. Two plans were simulated for each patient using 6 MV X-rays: a conventional multi-leaf (MLC parallel-opposed (AP-PA plan, and the same plan with additional MLC shaped segments (forward planned intensity modulated radiation therapy, FPIMRT. In order to compare plans, dose-volume histograms (DVHs of PTV, lungs, heart, spinal cord, breast, and thyroid were analyzed. The Inhomogeneity Coefficient (IC, the PTV receiving 95% of the prescription dose (V95, the normal tissue complication probability (NTCP and dose-volume parameters for the OARs were determined. Results the PTV coverage was improved (mean V95AP-PA = 95.9 and ICAP-PA = 0.4 vs. V95FPIMRT = 96.8 and ICFPIMRT = 0.31, p ≤ 0.05 by the FPIMRT technique compared to the conventional one. At the same time, NTCPs of lung, spinal cord and thyroid, and the volume of lung and thyroid receiving ≥ 30 Gy resulted significantly reduced when using the FPIMRT technique. Conclusions The FPIMRT technique can represent a very useful and, at the same time, simple method for improving PTV conformity while saving critical organs when large fields are needed as in Hodgkin's lymphoma.

  12. Sparing Healthy Tissue and Increasing Tumor Dose Using Bayesian Modeling of Geometric Uncertainties for Planning Target Volume Personalization

    International Nuclear Information System (INIS)

    Objective: To develop a mathematical tool that can update a patient's planning target volume (PTV) partway through a course of radiation therapy to more precisely target the tumor for the remainder of treatment and reduce dose to surrounding healthy tissue. Methods and Materials: Daily on-board imaging was used to collect large datasets of displacements for patients undergoing external beam radiation therapy for solid tumors. Bayesian statistical modeling of these geometric uncertainties was used to optimally trade off between displacement data collected from previously treated patients and the progressively accumulating data from a patient currently partway through treatment, to optimally predict future displacements for that patient. These predictions were used to update the PTV position and margin width for the remainder of treatment, such that the clinical target volume (CTV) was more precisely targeted. Results: Software simulation of dose to CTV and normal tissue for 2 real prostate displacement datasets consisting of 146 and 290 patients treated with a minimum of 30 fractions each showed that re-evaluating the PTV position and margin width after 8 treatment fractions reduced healthy tissue dose by 19% and 17%, respectively, while maintaining CTV dose. Conclusion: Incorporating patient-specific displacement patterns from early in a course of treatment allows PTV adaptation for the remainder of treatment. This substantially reduces the dose to healthy tissues and thus can reduce radiation therapy–induced toxicities, improving patient outcomes

  13. Is a single arc sufficient in volumetric-modulated arc therapy (VMAT) for complex-shaped target volumes?

    International Nuclear Information System (INIS)

    Purpose: To compare step-and-shoot intensity-modulated radiotherapy (ss-IMRT) with volumetric-modulated arc therapy (VMAT) for complex-shaped target volumes with a simultaneous integrated boost (SIB). Materials and methods: This retrospective planning study was based on 20 patients composed of prostate cancer (n = 5), postoperative (n = 5) or primary (n = 5) radiotherapy for pharyngeal cancer and for cancer of the paranasal sinuses (n = 5); a SIB with two or three dose levels was planned in all patients. For each patient, one ss-IMRT plan with direct-machine-parameter optimization (DMPO) and VMAT plans with one to three arcs (SmartArc technique) were generated in the Pinnacle planning system. Results: Single arc VMAT improved target coverage and dose homogeneity in radiotherapy for prostate cancer. Two and three VMAT arcs were required to achieve equivalent results compared to ss-IMRT in postoperative and primary radiotherapy for pharyngeal cancer, respectively. In radiotherapy for cancer of the paranasal sinuses, multiarc VMAT resulted in increased spread of low doses to the lenses and decreased target coverage in the region between the orbits. Conclusions: The complexity of the target volume determined whether single arc VMAT was equivalent to ss-IMRT. Multiple arc VMAT improved results compared to single arc VMAT at cost of increased delivery times, increased monitor unites and increased spread of low doses.

  14. Sparing Healthy Tissue and Increasing Tumor Dose Using Bayesian Modeling of Geometric Uncertainties for Planning Target Volume Personalization

    Energy Technology Data Exchange (ETDEWEB)

    Herschtal, Alan, E-mail: Alan.Herschtal@petermac.org [Department of Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, Melbourne (Australia); Faculty of Health, Arts and Design, Swinburne University of Technology, Melbourne (Australia); Te Marvelde, Luc [Department of Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, Melbourne (Australia); Mengersen, Kerrie [School of Mathematical Sciences, Science and Engineering Faculty, Queensland University of Technology, Brisbane (Australia); Foroudi, Farshad [Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne (Australia); The Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne (Australia); Eade, Thomas [Northern Sydney Cancer Centre, Radiation Oncology Department, Royal North Shore Hospital, St. Leonards, Sydney (Australia); Northern Clinical School, University of Sydney (Australia); Pham, Daniel [Department of Radiation Therapy, Peter MacCallum Cancer Centre, Melbourne (Australia); Caine, Hannah [Northern Sydney Cancer Centre, Radiation Oncology Department, Royal North Shore Hospital, St. Leonards, Sydney (Australia); Kron, Tomas [The Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne (Australia); Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne (Australia)

    2015-06-01

    Objective: To develop a mathematical tool that can update a patient's planning target volume (PTV) partway through a course of radiation therapy to more precisely target the tumor for the remainder of treatment and reduce dose to surrounding healthy tissue. Methods and Materials: Daily on-board imaging was used to collect large datasets of displacements for patients undergoing external beam radiation therapy for solid tumors. Bayesian statistical modeling of these geometric uncertainties was used to optimally trade off between displacement data collected from previously treated patients and the progressively accumulating data from a patient currently partway through treatment, to optimally predict future displacements for that patient. These predictions were used to update the PTV position and margin width for the remainder of treatment, such that the clinical target volume (CTV) was more precisely targeted. Results: Software simulation of dose to CTV and normal tissue for 2 real prostate displacement datasets consisting of 146 and 290 patients treated with a minimum of 30 fractions each showed that re-evaluating the PTV position and margin width after 8 treatment fractions reduced healthy tissue dose by 19% and 17%, respectively, while maintaining CTV dose. Conclusion: Incorporating patient-specific displacement patterns from early in a course of treatment allows PTV adaptation for the remainder of treatment. This substantially reduces the dose to healthy tissues and thus can reduce radiation therapy–induced toxicities, improving patient outcomes.

  15. Analysis of CBCT image registration methods and the planning target volume margins for liver cancers using lipiodol as a direct surrogate for target localization

    International Nuclear Information System (INIS)

    Objective: To analyze the transitional shifts between with different sets of cone-beam computed tomography (CBCT) and the planning CT for liver cancer patients, and calculate the margins from clinical target volume (CTV) to the planning target volume (PTV) with and without image guided radiotherapy (IGRT). Methods: Five liver cancer patients received radiotherapy after transcatheter arterial chemoembolization (TACE). The first CBCT images (CBCT1) were obtained with Elekta CBCT plus active breathing control (ABC) system before treatment. The second CBCT images (CBCT2) were obtained after correcting the set-up errors and the third CBCT images (CBCT3) were obtained after treatment. The CBCT images were registered and matched with the planning CT images using lipiodol as a direct surrogate for target localization. The PTV margins were calculated by comparing the shift between planning CT and CBCT according to formula M =2.5 (Σ doctor2 + Σ set-up2 + Σ transter2 )1/2. Paired t-test was used to compare the differences between the results from CBCT1, CBCT2 and CBCT3. Results: The average transition shifts in the left-right (LR), superior-inferior (SI) and anterior-posterior (AP) directions were 0.254, -0.612, 0.314 cm between planning CT and CBCT1; were 0.020, 0.014, -0.064 cm between planning CT and CBCT2; and they were -0.004, 0.042, -0.040 cm between planning CT and CBCT3. The PTV margins were LR 0.96 cm, SI 0.96 cm and AP 0.83 cm without IGRT, and LR 0.67 cm, SI 0.68 cm and AP 0.58 cm with IGRT. Conclusions: The PTV margins can be reduced by 3 mm with IGRT for liver cancer using lipiodol as a direct surrogate for target localization. (authors)

  16. Impact of 18F-FDG PET/CT on target volume delineation in recurrent or residual gynaecologic carcinoma

    International Nuclear Information System (INIS)

    To evaluate the impact of 18F-FDG PET/CT on target volume delineation in gynaecological cancer. F-FDG PET/CT based RT treatment planning was performed in 10 patients with locally recurrent (n = 5) or post-surgical residual gynaecological cancer (n = 5). The gross tumor volume (GTV) was defined by 4 experienced radiation oncologists first using contrast enhanced CT (GTVCT) and secondly using the fused 18F-FDG PET/CT datasets (GTVPET/CT). In addition, the GTV was delineated using the signal-to-background (SBR) ratio-based adaptive thresholding technique (GTVSBR). Overlap analysis were conducted to assess geographic mismatches between the GTVs delineated using the different techniques. Inter- and intra-observer variability were also assessed. The mean GTVCT (43.65 cm3) was larger than the mean GTVPET/CT (33.06 cm3), p = 0.02. In 6 patients, GTVPET/CT added substantial tumor extension outside the GTVCT even though 90.4% of the GTVPET/CT was included in the GTVCT and 30.2% of the GTVCT was found outside the GTVPET/CT. The inter- and intra-observer variability was not significantly reduced with the inclusion of 18F-FDG PET imaging (p = 0.23 and p = 0.18, respectively). The GTVSBR was smaller than GTVCT p ≤ 0.005 and GTVPET/CT p ≤ 0.005. The use of 18F-FDG PET/CT images for target volume delineation of recurrent or post-surgical residual gynaecological cancer alters the GTV in the majority of patients compared to standard CT-definition. The use of SBR-based auto-delineation showed significantly smaller GTVs. The use of PET/CT based target volume delineation may improve the accuracy of RT treatment planning in gynaecologic cancer

  17. Target Volume Delineation in Dynamic Positron Emission Tomography Based on Time Activity Curve Differences

    Science.gov (United States)

    Teymurazyan, Artur

    Tumor volume delineation plays a critical role in radiation treatment planning and simulation, since inaccurately defined treatment volumes may lead to the overdosing of normal surrounding structures and potentially missing the cancerous tissue. However, the imaging modality almost exclusively used to determine tumor volumes, X-ray Computed Tomography (CT), does not readily exhibit a distinction between cancerous and normal tissue. It has been shown that CT data augmented with PET can improve radiation treatment plans by providing functional information not available otherwise. Presently, static PET scans account for the majority of procedures performed in clinical practice. In the radiation therapy (RT) setting, these scans are visually inspected by a radiation oncologist for the purpose of tumor volume delineation. This approach, however, often results in significant interobserver variability when comparing contours drawn by different experts on the same PET/CT data sets. For this reason, a search for more objective contouring approaches is underway. The major drawback of conventional tumor delineation in static PET images is the fact that two neighboring voxels of the same intensity can exhibit markedly different overall dynamics. Therefore, equal intensity voxels in a static analysis of a PET image may be falsely classified as belonging to the same tissue. Dynamic PET allows the evaluation of image data in the temporal domain, which often describes specific biochemical properties of the imaged tissues. Analysis of dynamic PET data can be used to improve classification of the imaged volume into cancerous and normal tissue. In this thesis we present a novel tumor volume delineation approach (Single Seed Region Growing algorithm in 4D (dynamic) PET or SSRG/4D-PET) in dynamic PET based on TAC (Time Activity Curve) differences. A partially-supervised approach is pursued in order to allow an expert reader to utilize the information available from other imaging

  18. Determination of Internal Target Volume From a Single Positron Emission Tomography/Computed Tomography Scan in Lung Cancer

    International Nuclear Information System (INIS)

    Purpose: The use of four-dimensional computed tomography (4D-CT) to determine the tumor internal target volume (ITV) is usually characterized by high patient radiation exposure. The objective of this study was to propose and evaluate an approach that relies on a single static positron emission tomography (PET)/CT scan to determine the ITV, thereby eliminating the need for 4D-CT and thus reduce patient radiation dose. Methods and Materials: The proposed approach is based on the concept that the observed PET image is the result of a joint convolution of an ideal PET image (free from motion and partial volume effect) with a motion-blurring kernel (MBK) and partial volume effect. In this regard, the MBK and tumor ITV are then estimated from the deconvolution of this joint model. To test this technique, phantom and patient studies were performed using different sphere/tumor sizes and motion trajectories. In all studies, a 4D-CT and a PET/CT image of the sphere/tumor were acquired. The ITV from the proposed technique was then compared to the maximum intensity projection (MIP) volume of the 4D-CT images. A Dice coefficient of the two volumes was calculated to represent the similarity between the two ITVs. Results: The average ITVs of the proposed technique were 97.2% ± 0.3% and 81.0% ± 16.7% similar to the MIP volume in the phantom and patient studies, respectively. The average dice coefficients were 0.87 ± 0.05 and 0.73 ± 0.16, respectively, for the two studies. Conclusion: Using the proposed approach, a single static PET/CT scan has the potential to replace a 4D-CT to determine the tumor ITV. This approach has the added advantage of reducing patient radiation exposure and determining the tumor MBK compared to 4D-CT/MIP-CT.

  19. A Beam-Specific Planning Target Volume (PTV) Design for Proton Therapy to Account for Setup and Range Uncertainties

    International Nuclear Information System (INIS)

    Purpose: To report a method for explicitly designing a planning target volume (PTV) for treatment planning and evaluation in heterogeneous media for passively scattered proton therapy and scanning beam proton therapy using single-field optimization (SFO). Methods and Materials: A beam-specific PTV (bsPTV) for proton beams was derived by ray-tracing and shifting ray lines to account for tissue misalignment in the presence of setup error or organ motion. Range uncertainties resulting from inaccuracies in computed tomography–based range estimation were calculated for proximal and distal surfaces of the target in the beam direction. The bsPTV was then constructed based on local heterogeneity. The bsPTV thus can be used directly as a planning target as if it were in photon therapy. To test the robustness of the bsPTV, we generated a single-field proton plan in a virtual phantom. Intentional setup and range errors were introduced. Dose coverage to the clinical target volume (CTV) under various simulation conditions was compared between plans designed based on the bsPTV and a conventional PTV. Results: The simulated treatment using the bsPTV design performed significantly better than the plan using the conventional PTV in maintaining dose coverage to the CTV. With conventional PTV plans, the minimum coverage to the CTV dropped from 99% to 67% in the presence of setup error, internal motion, and range uncertainty. However, plans using the bsPTV showed minimal drop of target coverage from 99% to 94%. Conclusions: The conventional geometry-based PTV concept used in photon therapy does not work well for proton therapy. We investigated and validated a beam-specific PTV method for designing and evaluating proton plans.

  20. Defining Radiotherapy Target Volumes Using 18F-Fluoro-Deoxy-Glucose Positron Emission Tomography/Computed Tomography: Still a Pandora's Box?

    International Nuclear Information System (INIS)

    Purpose: We discuss the effect of 18F-fluoro-deoxy-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) data on target volume definition for radiotherapy planning. We compared the effect of various thresholding methods on the PET-based target volume vs. the standard CT-based tumor volume. Methods and Materials: Different thresholding methods were reviewed and compared to our PET-based gross tumor volume data obtained from a cohort of 31 non-small-cell lung carcinoma patients who had undergone preoperative PET/CT scans for staging. The feasibility and limitations of FDG-based PET/CT data on target volume delineation in radiotherapy planning have been demonstrated with frequently used approaches for target outlining such as the qualitative visual method and the fixed 15% or 40% of the maximal iso-uptake value threshold methods. Results: The relationship between PET-based and CT-based volumes generally suffers from poor correlation between the two image data sets, expressed in terms of a large statistical variation in gross tumor volume ratios, irrespective of the threshold method used. However, we found that the maximal signal/background ratios in non-small-cell lung carcinoma patients correlated well with the pathologic results, with an average ratio for adenocarcinoma, large cell carcinoma, and squamous cell carcinoma of 10.5 ± 3.5, 12.6 ± 2.8, and 14.1 ± 5.9, respectively. Conclusion: The fluctuations in tumor volume using different quantitative PET thresholding approaches did not depend on the thresholding method used. They originated from the nature of functional imaging in general and PET imaging in particular. Functional imaging will eventually be used for biologically tailored target radiotherapy volume definition not as a replacement of CT- or magnetic resonance imaging-based anatomic gross tumor volumes but with the methods complementing each other in a complex mosaic of distinct biologic target volumes.

  1. A clip-based protocol for breast boost radiotherapy provides clear target visualisation and demonstrates significant volume reduction over time

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Lorraine [Department of Radiation Oncology, Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Cox, Jennifer [Department of Radiation Oncology, Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Faculty of Health Sciences, University of Sydney, Sydney, New South Wales (Australia); Morgia, Marita [Department of Radiation Oncology, Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Atyeo, John [Faculty of Health Sciences, University of Sydney, Sydney, New South Wales (Australia); Lamoury, Gillian [Department of Radiation Oncology, Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia)

    2015-09-15

    The clinical target volume (CTV) for early stage breast cancer is difficult to clearly identify on planning computed tomography (CT) scans. Surgical clips inserted around the tumour bed should help to identify the CTV, particularly if the seroma has been reabsorbed, and enable tracking of CTV changes over time. A surgical clip-based CTV delineation protocol was introduced. CTV visibility and its post-operative shrinkage pattern were assessed. The subjects were 27 early stage breast cancer patients receiving post-operative radiotherapy alone and 15 receiving post-operative chemotherapy followed by radiotherapy. The radiotherapy alone (RT/alone) group received a CT scan at median 25 days post-operatively (CT1rt) and another at 40 Gy, median 68 days (CT2rt). The chemotherapy/RT group (chemo/RT) received a CT scan at median 18 days post-operatively (CT1ch), a planning CT scan at median 126 days (CT2ch), and another at 40 Gy (CT3ch). There was no significant difference (P = 0.08) between the initial mean CTV for each cohort. The RT/alone cohort showed significant CTV volume reduction of 38.4% (P = 0.01) at 40 Gy. The Chemo/RT cohort had significantly reduced volumes between CT1ch: median 54 cm{sup 3} (4–118) and CT2ch: median 16 cm{sup 3}, (2–99), (P = 0.01), but no significant volume reduction thereafter. Surgical clips enable localisation of the post-surgical seroma for radiotherapy targeting. Most seroma shrinkage occurs early, enabling CT treatment planning to take place at 7 weeks, which is within the 9 weeks recommended to limit disease recurrence.

  2. A clip-based protocol for breast boost radiotherapy provides clear target visualisation and demonstrates significant volume reduction over time

    International Nuclear Information System (INIS)

    The clinical target volume (CTV) for early stage breast cancer is difficult to clearly identify on planning computed tomography (CT) scans. Surgical clips inserted around the tumour bed should help to identify the CTV, particularly if the seroma has been reabsorbed, and enable tracking of CTV changes over time. A surgical clip-based CTV delineation protocol was introduced. CTV visibility and its post-operative shrinkage pattern were assessed. The subjects were 27 early stage breast cancer patients receiving post-operative radiotherapy alone and 15 receiving post-operative chemotherapy followed by radiotherapy. The radiotherapy alone (RT/alone) group received a CT scan at median 25 days post-operatively (CT1rt) and another at 40 Gy, median 68 days (CT2rt). The chemotherapy/RT group (chemo/RT) received a CT scan at median 18 days post-operatively (CT1ch), a planning CT scan at median 126 days (CT2ch), and another at 40 Gy (CT3ch). There was no significant difference (P = 0.08) between the initial mean CTV for each cohort. The RT/alone cohort showed significant CTV volume reduction of 38.4% (P = 0.01) at 40 Gy. The Chemo/RT cohort had significantly reduced volumes between CT1ch: median 54 cm3 (4–118) and CT2ch: median 16 cm3, (2–99), (P = 0.01), but no significant volume reduction thereafter. Surgical clips enable localisation of the post-surgical seroma for radiotherapy targeting. Most seroma shrinkage occurs early, enabling CT treatment planning to take place at 7 weeks, which is within the 9 weeks recommended to limit disease recurrence

  3. Target volume definition in conformal radiotherapy for prostate cancer: quality assurance in the MRC RT-01 trial

    International Nuclear Information System (INIS)

    Prior to randomization of patients into the UK Medical Research Council multicentre randomized trial (RT-01) of conformal radiotherapy (CFRT) in prostate cancer, clinicians at participating centres were required to complete a quality assurance (QA) clinical planning exercise to enable an investigation of inter-observer variability in gross target volume (GTV) and normal structure outlining. Thirteen participating centres and two investigators completed the clinical planning exercise of three practice planning cases. Clinicians were asked to draw outlines of the GTV, rectum and bladder on hard-copy computerized tomography (CT) films of the pelvis, which were transferred onto the Cadplan computer planning system by a single investigator. Centre, inferior and superior CT levels of GTV, rectum and bladder were noted, and volume calculations performed. Planning target volumes (PTV) were generated using automatic volume expansion of GTVs by a 1 cm margin. Anterior, right and left lateral beam eye views (BEV) of the PTVs were generated. Using a common central point, the BEV PTVs were superimposed for each beam direction of each case. Radial PTV variation was investigated by measurement of a novel parameter, termed the radial line measurement variation (RLMV). GTV central slice and length were defined with reasonable consistency. The RLMV analysis showed that the main part of the prostate gland, bladder and inferior rectum were outlined with good consistency among clinicians. However, the outlining of the prostatic apex, superior aspect of the prostate projecting into the bladder, seminal vesicles, the base of seminal vesicles and superior rectum were more variable. This exercise has demonstrated adequate consistency of GTV definition. The RLMV method of analysis indicates particular regions of clinician uncertainty. Appropriate feedback has been given to all participating clinicians, and the final RT-01 trial protocol has been modified to accommodate these findings

  4. Fee Increases and Target Income Hypothesis: Data from Quebec on Physicians' Compensation and Service Volumes

    OpenAIRE

    Contandriopoulos, Damien; Perroux, Mélanie

    2013-01-01

    Recent years have witnessed important public investments in physicians' compensation across Canada. The current paper uses data from Quebec to assess the impact of those investments on the volumes of services provided to the population. While total physician compensation costs, average physician compensation and average unit cost per service all rose extremely fast, the total number of services, number of services per capita and average number of services per physician either stagnated or dec...

  5. Target Volume Delineation in Oropharyngeal Cancer: Impact of PET, MRI, and Physical Examination

    International Nuclear Information System (INIS)

    Introduction: Sole utilization of computed tomography (CT) scans in gross tumor volume (GTV) delineation for head-and-neck cancers is subject to inaccuracies. This study aims to evaluate contributions of magnetic resonance imaging (MRI), positron emission tomography (PET), and physical examination (PE) to GTV delineation in oropharyngeal cancer (OPC). Methods: Forty-one patients with OPC were studied. All underwent contrast-enhanced CT simulation scans (CECTs) that were registered with pretreatment PETs and MRIs. For each patient, three sets of primary and nodal GTV were contoured. First, reference GTVs (GTVref) were contoured by the treating radiation oncologist (RO) using CT, MRI, PET, and PE findings. Additional GTVs were created using fused CT/PET scans (GTVctpet) and CT/MRI scans (GTVctmr) by two other ROs blinded to GTVref. To compare GTVs, concordance indices (CI) were calculated by dividing the respective overlap volumes by overall volumes. To evaluate the contribution of PE, composite GTVs derived from CT, MRI, and PET (GTVctpetmr) were compared with GTVref. Results: For primary tumors, GTVref was significantly larger than GTVctpet and GTVctmr (p 0.75), indicating that although the modalities were complementary, the added benefit was small in the context of CECTs. In addition, PE did not aid greatly in nodal GTV delineation. Conclusion: PET and MRI are complementary and combined use is ideal. However, the low CI (ctpetmr vs. ref) particularly for primary tumors underscores the limitations of defining GTVs using imaging alone. PE is invaluable and must be incorporated.

  6. Internal target volume determined with expansion margins beyond composite gross tumor volume in three-dimensional conformal radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Purpose: Gross tumor volume (GTV) of lung cancer defined by fast helical CT scan represents an image of moving tumor captured at a point in active respiratory movement. However, the method for defining internal margins beyond GTV to account for its expected physiologic movement and all variations in size and shape during the administration of radiation has not been established. The goal of this study was to determine the internal margins with expansion margins beyond individual GTVs defined with (1) fast scan at shallow free breathing (2) breath-hold scans at the end of tidal volume inspiration and expiration, and (3) 4-s slow scan to approximate the composite GTV of all scans. Methods and materials: A series of sequential CT scans were acquired with (1) a fast helical scan at shallow free breathing and (2) breath-hold scans at the end of tidal volume expiration and inspiration for the first 6 patients, and (3) a 4-s slow scan at quiet free breathing, which was added for the latter 7 patients. We fused breath-hold scans and the 4-s slow scan to the fast scan at shallow free breathing to generate the composite GTV. Margins necessary to encompass the composite GTV beyond individual GTVs defined by either fast scan at quiet free breathing, breath-hold scans, or the 4-s slow scan at quiet free breathing were defined as expansion or internal margins and termed the internal target volumes. The centroid of the tumor volume was also used as another reference for tumor movement. Results: Thirteen patients with 14 tumors were enrolled into the study. Substantial tumor movement was noted by either the extent of internal margins beyond each GTV or the movement of the centroid. Internal margins varied significantly according to the method of CT scanning for determination of GTV. Even for tumors in the same lobe of the lung, a wide range of internal margins and significant variation in the centroid movement in all directions (x, y, and z) were observed. The GTV of a single fast

  7. Evaluation of atlas based auto-segmentation for head and neck target volume delineation in adaptive/replan IMRT

    International Nuclear Information System (INIS)

    IMRT for head and neck patients requires clinicians to delineate clinical target volumes (CTV) on a planning-CT (>2hrs/patient). When patients require a replan-CT, CTVs must be re-delineated. This work assesses the performance of atlas-based autosegmentation (ABAS), which uses deformable image registration between planning and replan-CTs to auto-segment CTVs on the replan-CT, based on the planning contours. Fifteen patients with planning-CT and replan-CTs were selected. One clinician delineated CTVs on the planning-CTs and up to three clinicians delineated CTVs on the replan-CTs. Replan-CT volumes were auto-segmented using ABAS using the manual CTVs from the planning-CT as an atlas. ABAS CTVs were edited manually to make them clinically acceptable. Clinicians were timed to estimate savings using ABAS. CTVs were compared using dice similarity coefficient (DSC) and mean distance to agreement (MDA). Mean inter-observer variability (DSC>0.79 and MDA<2.1mm) was found to be greater than intra-observer variability (DSC>0.91 and MDA<1.5mm). Comparing ABAS to manual CTVs gave DSC=0.86 and MDA=2.07mm. Once edited, ABAS volumes agreed more closely with the manual CTVs (DSC=0.87 and MDA=1.87mm). The mean clinician time required to produce CTVs reduced from 169min to 57min when using ABAS. ABAS segments volumes with accuracy close to inter-observer variability however the volumes require some editing before clinical use. Using ABAS reduces contouring time by a factor of three.

  8. Microspheres targeted with a mesothelin antibody and loaded with doxorubicin reduce tumor volume of human mesotheliomas in xenografts

    International Nuclear Information System (INIS)

    Malignant mesotheliomas (MMs) are chemoresistant tumors related to exposure to asbestos fibers. The long latency period of MM (30-40 yrs) and heterogeneity of tumor presentation make MM difficult to diagnose and treat at early stages. Currently approved second-line treatments following surgical resection of MMs include a combination of cisplatin or carboplatin (delivered systemically) and pemetrexed, a folate inhibitor, with or without subsequent radiation. The systemic toxicities of these treatments emphasize the need for more effective, localized treatment regimens. Acid-prepared mesoporous silica (APMS) microparticles were loaded with doxorubicin (DOX) and modified externally with a mesothelin (MB) specific antibody before repeated intraperitoneal (IP) injections into a mouse xenograft model of human peritoneal MM. The health/weight of mice, tumor volume/weight, tumor necrosis and cell proliferation were evaluated in tumor-bearing mice receiving saline, DOX high (0.2 mg/kg), DOX low (0.05 mg/kg), APMS-MB, or APMS-MB-DOX (0.05 mg/kg) in saline. Targeted therapy (APMS-MB-DOX at 0.05 mg/kg) was more effective than DOX low (0.05 mg/kg) and less toxic than treatment with DOX high (0.2 mg/kg). It also resulted in the reduction of tumor volume without loss of animal health and weight, and significantly decreased tumor cell proliferation. High pressure liquid chromatography (HPLC) of tumor tissue confirmed that APMS-MB-DOX particles delivered DOX to target tissue. Data suggest that targeted therapy results in greater chemotherapeutic efficacy with fewer adverse side effects than administration of DOX alone. Targeted microparticles are an attractive option for localized drug delivery

  9. Evaluation of dose-volume histogram parameters (V20 and mean dose) in lung cancer adaptive radiotherapy with design of composite lung volumes (ITV; Evaluacion de parametros del histograma dosis-volumen (V20 y dosis media) en radioterapia adaptada de cancer de pulmon con diseno de volumenes pulmonares compuestos (Internal Target Volume, ITV)

    Energy Technology Data Exchange (ETDEWEB)

    Monroy Anton, J. L.; Solar Tortosa, M.; Lopez Munoz, M.; Navarro Bergada, A.; Estornell gualde, M. A.; Melchor Iniguez, M.

    2013-07-01

    Physiological respiratory motion is a challenge in external radiotherapy for lung tumors. In adaptive radiotherapy, changing position of the target volume should be reflected in the simulation procedure and taken into account in the design of volumes for CTV/PTV proper coverage. This may be achieved through the design of an Internal Target Volume (ITV) as indicated in ICRU-62. However, the Dose-Volume Histogram (DVH) evaluation of the doses received by the healthy lung may vary in the case of designing a single lung volume, compared to the composite lung volume obtained with the fusion of normal breathing, inspiration and expiration (ITV{sub l}ung). (Author)

  10. Development of whole-building energy design targets for commercial buildings: Phase 1, Planning: Volume 2, Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Crawley, D.B.; Briggs, R.S.; Jones, J.W.; Seaton, W.W.; Kaufman, J.E.; Deringer, J.J.; Kennett, E.W.

    1987-08-01

    This is the second volume of the Phase 1 report and discusses the 10 tasks performed in Phase 1. The objective of this research is to develop a methodology for setting energy design targets to provide voluntary guidelines for the buildings industry. The whole-building energy targets project is being conducted at the Pacific Northwest Laboratory (PNL) for the US Department of Energy (DOE) to encourage the construction of energy-efficient buildings by informing designers and owners about cost-effective goals for energy use in new commercial buildings. The outcome of this research will be a flexible methodology for setting such targets. The tasks are listed and discussed in this report as follows: Task 1 - Develop Detailed Project Goals and Objectives; Task 2 - Establish Buildings-Industry Liaison; Task 3 - Develop Approaches to the Energy Targets Model, Building Operations, and Climate; Task 4 - Develop an Approach for Treating Economic Considerations; Task 5 - Develop an Approach for Treating Energy Sources; Task 6 - Collect Energy-Use Data; Task 7 - Survey Energy Expert Opinion; Task 8 - Evaluation Procedure Specification and Integration; Task 9 - Phase 1 Report Development; and Task 10 - Phase 1 Review Planning.

  11. Physics of laser fusion. Volume II. Diagnostics of experiments on laser fusion targets at LLNL

    International Nuclear Information System (INIS)

    These notes present the experimental basis and status for laser fusion as developed at LLNL. There are two other volumes in this series: Vol. I, by C.E. Max, presents the theoretical laser-plasma interaction physics; Vol. III, by J.F. Holzrichter et al., presents the theory and design of high-power pulsed lasers. A fourth volume will present the theoretical implosion physics. The notes consist of six sections. The first, an introductory section, provides some of the history of inertial fusion and a simple explanation of the concepts involved. The second section presents an extensive discussion of diagnostic instrumentation used in the LLNL Laser Fusion Program. The third section is a presentation of laser facilities and capabilities at LLNL. The purpose here is to define capability, not to derive how it was obtained. The fourth and fifth sections present the experimental data on laser-plasma interaction and implosion physics. The last chapter is a short projection of the future

  12. Physics of laser fusion. Volume II. Diagnostics of experiments on laser fusion targets at LLNL

    Energy Technology Data Exchange (ETDEWEB)

    Ahlstrom, H.G.

    1982-01-01

    These notes present the experimental basis and status for laser fusion as developed at LLNL. There are two other volumes in this series: Vol. I, by C.E. Max, presents the theoretical laser-plasma interaction physics; Vol. III, by J.F. Holzrichter et al., presents the theory and design of high-power pulsed lasers. A fourth volume will present the theoretical implosion physics. The notes consist of six sections. The first, an introductory section, provides some of the history of inertial fusion and a simple explanation of the concepts involved. The second section presents an extensive discussion of diagnostic instrumentation used in the LLNL Laser Fusion Program. The third section is a presentation of laser facilities and capabilities at LLNL. The purpose here is to define capability, not to derive how it was obtained. The fourth and fifth sections present the experimental data on laser-plasma interaction and implosion physics. The last chapter is a short projection of the future.

  13. Chemoradiation for Ductal Pancreatic Carcinoma: Principles of Combining Chemotherapy with Radiation, Definition of Target Volume and Radiation Dose

    Directory of Open Access Journals (Sweden)

    Heinemann V

    2005-05-01

    Full Text Available Review of the role of chemoradiotherapy in the treatment of locally advanced pancreatic cancer with a specific focus on the technical feasibility and the integration of chemoradiotherapy into multimodal treatment concepts. Combined chemoradiotherapy of pancreatic cancer is a safe treatment with an acceptable profile of side effects when applied with modern planning and radiation techniques as well as considering tissue tolerance. Conventionally fractionated radiation regimens with total doses of 45-50 Gy and small-volume boost radiation with 5.4 Gy have found the greatest acceptance. Locoregional lymphatic drainage should be included in the planning of target volumes because the risk of tumor involvement and local or loco-regional recurrence is high. Up to now, 5-fluorouracil has been considered the "standard" agent for concurrent chemoradiotherapy. The role of gemcitabine given concurrently with radiation has not yet been defined, since high local efficacy may also be accompanied by enhanced toxicities. In addition, no dose or administration form has been determined to be "standard" up to now. The focus of presently ongoing research is to define an effective and feasible regimen of concurrent chemoradiotherapy. While preliminary results indicate promising results using gemcitabine-based chemoradiotherapy, reliable data derived from mature phase III trials are greatly needed. Intensity-modulated radiotherapy has been developed to improve target-specific radiation and to reduce organ toxicity. Its clinical relevance still needs to be defined.

  14. Technical review of target volume delineation on the posterior fossa tumor: an optimal head and neck position

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sang Min; Lee, Sang Wook; Ahn, Seung Do; Kim, Jong Hoon; Yi, Byong Yong; Ra, Young Shin; Ghim, Thad; Choi, Eun Kyung [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

    2003-03-01

    To explore a 3D conformal radiotherapy technique for a posterior fossa boost, and the potential advantages of a prone position for such radiotherapy, A CT simulator and 3D conformal radiotherapy planning system was used for the posterior fossa boost treatment of a 13-year-old medulloblastoma patient. He was placed in the prone position and immobilized with an aquaplast mask and immobilization mold. CT scans were obtained of the brain from the top of the skull to the lower neck, with IV contrast enhancement. The target volume and normal structures were delineated on each slice, with treatment planning performed using non-coplanar conformal beams. The CT scans, and treatment in the prone position, were performed successfully. In the prone position, the definition of the target volume was made easier due to the well enhanced tentorium. In addition, the posterior fossa was located anteriorly, and with the greater choice of beam arrangements, more accurate treatment planning was possible as the primary beams were not obstructed by the treatment table. A posterior fossa boost, in the prone position, is feasible in cooperating patients, but further evaluation is needed to define the optimal and most comfortable treatment positions.

  15. Histopathological correlation of 11C-choline PET scans for target volume definition in radical prostate radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: To evaluate the accuracy of 11C-choline PET scans in defining dominant intraprostatic lesions (DILs) for radiotherapy target volume definition. Material and methods: Eight men with prostate cancer who had 11C-choline PET scans prior to radical prostatectomy were studied. Several methods were used to contour the DIL on the PET scans: visual, PET Edge, Region Grow, absolute standardised uptake value (SUV) thresholds and percentage of maximum SUV thresholds. Prostatectomy specimens were sliced in the transverse plane and DILs were delineated on these by a pathologist. These were then compared with the PET scans. The accuracy of correlation was assessed by the Dice similarity coefficient (DSC) and the Youden index. Results: The contouring method resulting in both the highest DSC and the highest Youden index was 60% of the maximum SUV (SUV60%), with values of 0.64 and 0.51, respectively. However SUV60% was not statistically significantly better than all of the other methods by either measure. Conclusions: Although not statistically significant, SUV60% resulted in the best correlation between 11C-choline PET and pathology amongst all the methods studied. The degree of correlation shown here is consistent with previous studies that have justified using imaging for DIL radiotherapy target volume definition.

  16. Impact of 18F-FDG PET/CT on target volume delineation in recurrent or residual gynaecologic carcinoma

    Directory of Open Access Journals (Sweden)

    Vees Hansjörg

    2012-10-01

    Full Text Available Abstract Background To evaluate the impact of 18F-FDG PET/CT on target volume delineation in gynaecological cancer. Methods F-FDG PET/CT based RT treatment planning was performed in 10 patients with locally recurrent (n = 5 or post-surgical residual gynaecological cancer (n = 5. The gross tumor volume (GTV was defined by 4 experienced radiation oncologists first using contrast enhanced CT (GTVCT and secondly using the fused 18F-FDG PET/CT datasets (GTVPET/CT. In addition, the GTV was delineated using the signal-to-background (SBR ratio-based adaptive thresholding technique (GTVSBR. Overlap analysis were conducted to assess geographic mismatches between the GTVs delineated using the different techniques. Inter- and intra-observer variability were also assessed. Results The mean GTVCT (43.65 cm3 was larger than the mean GTVPET/CT (33.06 cm3, p = 0.02. In 6 patients, GTVPET/CT added substantial tumor extension outside the GTVCT even though 90.4% of the GTVPET/CT was included in the GTVCT and 30.2% of the GTVCT was found outside the GTVPET/CT. The inter- and intra-observer variability was not significantly reduced with the inclusion of 18F-FDG PET imaging (p = 0.23 and p = 0.18, respectively. The GTVSBR was smaller than GTVCT p ≤ 0.005 and GTVPET/CT p ≤ 0.005. Conclusions The use of 18F-FDG PET/CT images for target volume delineation of recurrent or post-surgical residual gynaecological cancer alters the GTV in the majority of patients compared to standard CT-definition. The use of SBR-based auto-delineation showed significantly smaller GTVs. The use of PET/CT based target volume delineation may improve the accuracy of RT treatment planning in gynaecologic cancer.

  17. FDG-PET/CT imaging for staging and target volume delineation in conformal radiotherapy of anal carcinoma

    International Nuclear Information System (INIS)

    FDG-PET/CT imaging has an emerging role in staging and treatment planning of various tumor locations and a number of literature studies show that also the carcinoma of the anal canal may benefit from this diagnostic approach. We analyzed the potential impact of FDG-PET/CT in stage definition and target volume delineation of patients affected by carcinoma of the anal canal and candidates for curative radiotherapy. Twenty seven patients with biopsy proven anal carcinoma were enrolled. Pathology was squamous cell carcinoma in 20 cases, cloacogenic carcinoma in 3, adenocarcinoma in 2, and basal cell carcinoma in 2. Simulation was performed by PET/CT imaging with patient in treatment position. Gross Tumor Volume (GTV) and Clinical Target Volume (CTV) were drawn on CT and on PET/CT fused images. PET-GTV and PET-CTV were respectively compared to CT-GTV and CT-CTV by Wilcoxon rank test for paired data. PET/CT fused images led to change the stage in 5/27 cases (18.5%): 3 cases from N0 to N2 and 2 from M0 to M1 leading to change the treatment intent from curative to palliative in a case. Based on PET/CT imaging, GTV and CTV contours changed in 15/27 (55.6%) and in 10/27 cases (37.0%) respectively. PET-GTV and PET-CTV resulted significantly smaller than CT-GTV (p = 1.2 × 10-4) and CT-CTV (p = 2.9 × 10-4). PET/CT-GTV and PET/CT-CTV, that were used for clinical purposes, were significantly greater than CT-GTV (p = 6 × 10-5) and CT-CTV (p = 6 × 10-5). FDG-PET/CT has a potential relevant impact in staging and target volume delineation of the carcinoma of the anal canal. Clinical stage variation occurred in 18.5% of cases with change of treatment intent in 3.7%. The GTV and the CTV changed in shape and in size based on PET/CT imaging

  18. Correlation between target volume and electron transport effects affecting heterogeneity corrections in stereotactic body radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Recently, stereotactic body radiotherapy (SBRT) for lung cancer is conducted with heterogeneity-corrected treatment plans, as the correction greatly affects the dose delivery to the lung tumor. In this study, the correlation between the planning target volume (PTV) and the dose delivery is investigated by separation of the heterogeneity correction effects into photon attenuation and electron transport. Under Institutional Review Board exemption status, 74 patients with lung cancer who were treated with SBRT were retrospectively evaluated. All treatment plans were generated using an anisotropic analytical algorithm (AAA) of an Eclipse (Varian Medical Systems, Palo Alto, CA) treatment planning system. Two additional plans were created using the same treatment parameters (monitor units, beam angles and energy): a plan with no heterogeneity correction (NC), and a plan calculated with a pencil beam convolution algorithm (PBC). Compared with NC, AAA and PBC isocenter doses were on average 13.4% and 21.8% higher, respectively. The differences in the isocenter dose and the dose coverage for 95% of the PTV (D95%) between PBC and AAA were correlated logarithmically (ρ = 0.78 and ρ = 0.46, respectively) with PTV. Although D95% calculated with AAA was in general 2.9% larger than that for NC, patients with a small PTV showed a negative ΔD95% for AAA due to the significant effect of electron transport. The PTV volume shows logarithmic correlation with the effects of the lateral electron transport. These findings indicate that the dosimetric metrics and prescription, especially in clinical trials, should be clearly evaluated in the context of target volume characteristics and with proper heterogeneity correction. (author)

  19. 鼻咽癌临床靶区定义%Definition of clinical target volume (CTV) for nasopharyngeal carcinoma

    Institute of Scientific and Technical Information of China (English)

    林少俊; 潘建基; 郭巧娟

    2011-01-01

    Radiation therapy is the mainstay treatment modality for nasopharyngeal carcinoma (NPC), and the outcome is well associated to radiation dose. As a precise radiation technology, intensity-modulated radiotherapy (IMRT) offers the possibility of improving survival and simultaneously protect the surrounding normal tissue. The improvement of local control by IMRT has been well confirmed by a number of studies form domestic and abroad. However, the selection and definition of clinical target volume (CTV) for nasopharyngeal carcinoma has not yet reached a consensus. This article aimed to discovery the direction and mode for future research of reducing the treatment volume by reviewing the domestic and international development of CTV.%鼻咽癌为放射剂量相关性恶性肿瘤,放射治疗是鼻咽癌的首选治疗方法.调强放射治疗作为精确的放疗技术为提高剂量、保护周围正常组织提供了可能,国内外多家放疗中心的研究结果己证实调强放疗可提高鼻咽癌局部控制率.然而,当前对鼻咽癌的亚临床靶区(clinical target volume,CTV)的界定尚未达成共识,本文通过回顾国内外鼻咽癌CTV定义的发展过程,探讨未来缩小鼻咽癌靶区定义的发展方向和模式.

  20. Automated biological target volume delineation for radiotherapy treatment planning using FDG-PET/CT

    International Nuclear Information System (INIS)

    This study compared manually delineated gross tumour volume (GTV) and automatically generated biological tumour volume (BTV) based on fluoro-deoxy-glucose (FDG) positron emission tomography (PET)/CT to assess the robustness of predefined PET algorithms for radiotherapy (RT) planning in routine clinical practice. RT-planning data from 20 consecutive patients (lung- (40%), oesophageal- (25%), gynaecological- (25%) and colorectal (10%) cancer) who had undergone FDG-PET/CT planning between 08/2010 and 09/2011 were retrospectively analysed, five of them underwent neoadjuvant chemotherapy before radiotherapy. In addition to manual GTV contouring, automated segmentation algorithms were applied–among these 38%, 42%, 47% and 50% SUVmax as well as the PERCIST total lesion glycolysis (TLG) algorithm. Different ratios were calculated to assess the overlap of GTV and BTV including the conformity index and the ratio GTV included within the BTV. Median age of the patients was 66 years and median tumour SUVmax 9.2. Median size of the GTVs defined by the radiation oncologist was 43.7 ml. Median conformity indices were between 30.0–37.8%. The highest amount of BTV within GTV was seen with the 38% SUVmax algorithm (49.0%), the lowest with 50% SUVmax (36.0%). Best agreement was obtained for oesophageal cancer patients with a conformity index of 56.4% and BTV within GTV ratio of 71.1%. At present there is only low concordance between manually derived GTVs and automatically segmented FDG-PET/CT based BTVs indicating the need for further research in order to achieve higher volumetric conformity and therefore to get access to the full potential of FDG-PET/CT for optimization of radiotherapy planning

  1. Effect of interfractional shoulder motion on low neck nodal targets for patients treated using volume modulated arc therapy (VMAT

    Directory of Open Access Journals (Sweden)

    Kevin Casey

    2014-03-01

    Full Text Available Purpose: To quantify the dosimetric impact of interfractional shoulder motion on targets in the low neck for head and neck patients treated with volume modulated arc therapy (VMAT.Methods: Three patients with head and neck cancer were selected. All three required treatment to nodal regions in the low neck in addition to the primary tumor site. The patients were immobilized during simulation and treatment with a custom thermoplastic mask covering the head and shoulders. One VMAT plan was created for each patient utilizing two full 360° arcs and a second plan was created consisting of two superior VMAT arcs matched to an inferior static AP supraclavicular field. A CT-on-rails alignment verification was performed weekly during each patient’s treatment course. The weekly CT images were registered to the simulation CT and the target contours were deformed and applied to the weekly CT. The two VMAT plans were copied to the weekly CT datasets and recalculated to obtain the dose to the deformed low neck contours.Results: The average observed shoulder position shift in any single dimension relative to simulation was 2.5 mm. The maximum shoulder shift observed in a single dimension was 25.7 mm. Low neck target mean doses, normalized to simulation and averaged across all weekly recalculations were 0.996, 0.991, and 1.033 (Full VMAT plan and 0.986, 0.995, and 0.990 (Half-Beam VMAT plan for the three patients, respectively. The maximum observed deviation in target mean dose for any individual weekly recalculation was 6.5%, occurring with the Full VMAT plan for Patient 3.Conclusion: Interfractional variation in dose to low neck nodal regions was quantified for three head and neck patients treated with VMAT. Mean dose was 3.3% higher than planned for one patient using a Full VMAT plan. A Half-Beam technique is likely a safer choice when treating the supraclavicular region with VMAT.-------------------------------------------Cite this article as: Casey K

  2. Accuracy of relocation, evaluation of geometric uncertainties and clinical target volume (CTV) to planning target volume (PTV) margin in fractionated stereotactic radiotherapy for intracranial tumors using relocatable Gill-Thomas-Cosman (GTC) frame.

    Science.gov (United States)

    Das, Saikat; Isiah, Rajesh; Rajesh, B; Ravindran, B Paul; Singh, Rabi Raja; Backianathan, Selvamani; Subhashini, J

    2011-01-01

    The present study is aimed at determination of accuracy of relocation of Gill-Thomas-Cosman frame during fractionated stereotactic radiotherapy. The study aims to quantitatively determine the magnitudes of error in anteroposterior, mediolateral and craniocaudal directions, and determine the margin between clinical target volume to planning target volume based on systematic and random errors. Daily relocation error was measured using depth helmet and measuring probe. Based on the measurements, translational displacements in anteroposterior (z), mediolateral (x), and craniocaudal (y) directions were calculated. Based on the displacements in x, y and z directions, systematic and random error were calculated and three-dimensional radial displacement vector was determined. Systematic and random errors were used to derive CTV to PTV margin. The errors were within ± 2 mm in 99.2% cases in anteroposterior direction (AP), in 99.6% cases in mediolateral direction (ML), and in 97.6% cases in craniocaudal direction (CC). In AP, ML and CC directions, systematic errors were 0.56, 0.38, 0.42 mm and random errors were 1.86, 1.36 and 0.73 mm, respectively. Mean radial displacement was 1.03 mm ± 0.34. CTV to PTV margins calculated by ICRU formula were 1.86, 1.45 and 0.93 mm; by Stroom's formula they were 2.42, 1.74 and 1.35 mm; by van Herk's formula they were 2.7, 1.93 and 1.56 mm (AP, ML and CC directions). Depth helmet with measuring probe provides a clinically viable way for assessing the relocation accuracy of GTC frame. The errors were within ± 2 mm in all directions. Systematic and random errors were more along the anteroposterior axes. According to the ICRU formula, a margin of 2 mm around the tumor seems to be adequate. PMID:21587166

  3. The ADVANCE project: Formal evaluation of the targeted deployment. Volume 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    ADVANCE [Advanced Driver and Vehicle Advisory Navigation ConcEpt] was a public/private partnership conceived and developed by four founding parties. The founding parties include the Federal Highway Administration (FHWA), the Illinois Department of Transportation (IDOT), the University of Illinois at Chicago and Northwestern University operating together under the auspices of the Illinois Universities Transportation Research Consortium (IUTRC), and Motorola, Inc. The major responsibilities of each party are fully described in the Project agreement. Subsequently, these four were joined on the Steering Committee by the American Automobile Association (AAA). This unique blending of public sector, private sector and university interests, augmented by more than two dozen other private sector participants, provided a strong set of resources for ADVANCE. The ADVANCE test area covered over 300 square miles including portions of the City of Chicago and 40 northwest suburban communities. The Project encompasses the high growth areas adjacent to O`Hare International Airport, the Schaumbura/Hoffman Estates office and retail complexes, and the Lake-Cook Road development corridor. It also includes major sports and entertainment complexes such as the Arlington International Racecourse and the Rosemont Horizon. The population in the area is more than 750,000. This volume provides a summary of the insights and achievements made as a result of this field test, and selected appendices containing more detailed information.

  4. Intensity modulated radiotherapy for high risk prostate cancer based on sentinel node SPECT imaging for target volume definition

    International Nuclear Information System (INIS)

    The RTOG 94-13 trial has provided evidence that patients with high risk prostate cancer benefit from an additional radiotherapy to the pelvic nodes combined with concomitant hormonal ablation. Since lymphatic drainage of the prostate is highly variable, the optimal target volume definition for the pelvic lymph nodes is problematic. To overcome this limitation, we tested the feasibility of an intensity modulated radiation therapy (IMRT) protocol, taking under consideration the individual pelvic sentinel node drainage pattern by SPECT functional imaging. Patients with high risk prostate cancer were included. Sentinel nodes (SN) were localised 1.5–3 hours after injection of 250 MBq 99mTc-Nanocoll using a double-headed gamma camera with an integrated X-Ray device. All sentinel node localisations were included into the pelvic clinical target volume (CTV). Dose prescriptions were 50.4 Gy (5 × 1.8 Gy / week) to the pelvis and 70.0 Gy (5 × 2.0 Gy / week) to the prostate including the base of seminal vesicles or whole seminal vesicles. Patients were treated with IMRT. Furthermore a theoretical comparison between IMRT and a three-dimensional conformal technique was performed. Since 08/2003 6 patients were treated with this protocol. All patients had detectable sentinel lymph nodes (total 29). 4 of 6 patients showed sentinel node localisations (total 10), that would not have been treated adequately with CT-based planning ('geographical miss') only. The most common localisation for a probable geographical miss was the perirectal area. The comparison between dose-volume-histograms of IMRT- and conventional CT-planning demonstrated clear superiority of IMRT when all sentinel lymph nodes were included. IMRT allowed a significantly better sparing of normal tissue and reduced volumes of small bowel, large bowel and rectum irradiated with critical doses. No gastrointestinal or genitourinary acute toxicity Grade 3 or 4 (RTOG) occurred. IMRT based on sentinel lymph node

  5. Intensity modulated radiotherapy for high risk prostate cancer based on sentinel node SPECT imaging for target volume definition

    Directory of Open Access Journals (Sweden)

    Anastasiadis Aristotelis

    2005-07-01

    Full Text Available Abstract Background The RTOG 94-13 trial has provided evidence that patients with high risk prostate cancer benefit from an additional radiotherapy to the pelvic nodes combined with concomitant hormonal ablation. Since lymphatic drainage of the prostate is highly variable, the optimal target volume definition for the pelvic lymph nodes is problematic. To overcome this limitation, we tested the feasibility of an intensity modulated radiation therapy (IMRT protocol, taking under consideration the individual pelvic sentinel node drainage pattern by SPECT functional imaging. Methods Patients with high risk prostate cancer were included. Sentinel nodes (SN were localised 1.5–3 hours after injection of 250 MBq 99mTc-Nanocoll using a double-headed gamma camera with an integrated X-Ray device. All sentinel node localisations were included into the pelvic clinical target volume (CTV. Dose prescriptions were 50.4 Gy (5 × 1.8 Gy / week to the pelvis and 70.0 Gy (5 × 2.0 Gy / week to the prostate including the base of seminal vesicles or whole seminal vesicles. Patients were treated with IMRT. Furthermore a theoretical comparison between IMRT and a three-dimensional conformal technique was performed. Results Since 08/2003 6 patients were treated with this protocol. All patients had detectable sentinel lymph nodes (total 29. 4 of 6 patients showed sentinel node localisations (total 10, that would not have been treated adequately with CT-based planning ('geographical miss' only. The most common localisation for a probable geographical miss was the perirectal area. The comparison between dose-volume-histograms of IMRT- and conventional CT-planning demonstrated clear superiority of IMRT when all sentinel lymph nodes were included. IMRT allowed a significantly better sparing of normal tissue and reduced volumes of small bowel, large bowel and rectum irradiated with critical doses. No gastrointestinal or genitourinary acute toxicity Grade 3 or 4 (RTOG

  6. SU-E-J-75: Importance of 4DCT for Target Volume Definition in Stereotactic Lung Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: We aimed to investigate the importance of 4DCT for lung tumors treated with SBRT and whether maximum intensity projection (MIP) and free breathing (FB) images can compansate for tumor movement. Methods: Six patients with primary lung cancer and 2 patients with lung metastasis with a median age of 69.5 (42–86) were included. Patients were positioned supine on a vacuum bag. In addition to FB planning CT images, 4DCT images were obtained at 3 mm intervals using Varian RPM system with (Siemens Somatom Sensetion 64). MIP series were reconstructed using 4DCT images. PTV-FB and PTV-MIP (GTV+5mm) volumes were contoured using FB and MIP series, respectively. GTVs were defined on each of eight different breathing phase images and were merged to create the ITV. PTV-4D was generated with a 5 mm margin to ITV. PTV-MIP and PTV-4D contours were copied to FB CT series and treatment plans for PTV-MIP and PTV-FB were generated using RapidArc (2 partial arc) technique in Eclipse (version 11, AAA algorithm). The prescription dose was 5600cGy in 7 fractions. ITV volumes receiving prescription dose (%) and V95 for ITV were calculated for each treatment plan. Results: The mean PTV-4B, PTV-MIP and PTV-FB volumes were 23.2 cc, 15.4cc ve 11cc respectively. Median volume of ITV receiving the prescription dose was 34.6% (16.4–70 %) and median V95 dose for ITV was 1699cGy (232cGy-5117cGy) in the plan optimized for PTV-FB as the reference. When the plan was optimized for PTV-MIP, median ITV volume receiving the prescription dose was 67.15% (26–86%) and median V95 dose for ITV was 4231cGy (1735cGy-5290cGy). Conclusion: Images used in lung SBRT are critical for treatment quality; FB and MIP images did not compensate target movement, therefore 4DCT images should be obtained for all patients undergoing lung SBRT or the safety margins should be adjusted

  7. Planning target volume margins for prostate radiotherapy using daily electronic portal imaging and implanted fiducial markers

    International Nuclear Information System (INIS)

    Fiducial markers and daily electronic portal imaging (EPI) can reduce the risk of geographic miss in prostate cancer radiotherapy. The purpose of this study was to estimate CTV to PTV margin requirements, without and with the use of this image guidance strategy. 46 patients underwent placement of 3 radio-opaque fiducial markers prior to prostate RT. Daily pre-treatment EPIs were taken, and isocenter placement errors were corrected if they were ≥ 3 mm along the left-right or superior-inferior axes, and/or ≥ 2 mm along the anterior-posterior axis. During-treatment EPIs were then obtained to estimate intra-fraction motion. Without image guidance, margins of 0.57 cm, 0.79 cm and 0.77 cm, along the left-right, superior-inferior and anterior-posterior axes respectively, are required to give 95% probability of complete CTV coverage each day. With the above image guidance strategy, these margins can be reduced to 0.36 cm, 0.37 cm and 0.37 cm respectively. Correction of all isocenter placement errors, regardless of size, would permit minimal additional reduction in margins. Image guidance, using implanted fiducial markers and daily EPI, permits the use of narrower PTV margins without compromising coverage of the target, in the radiotherapy of prostate cancer

  8. Are We Ready for Positron Emission Tomography/Computed Tomography-based Target Volume Definition in Lymphoma Radiation Therapy?

    International Nuclear Information System (INIS)

    Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has become indispensable for the clinical management of lymphomas. With consistent evidence that it is more accurate than anatomic imaging in the staging and response assessment of many lymphoma subtypes, its utility continues to increase. There have therefore been efforts to incorporate PET/CT data into radiation therapy decision making and in the planning process. Further, there have also been studies investigating target volume definition for radiation therapy using PET/CT data. This article will critically review the literature and ongoing studies on the above topics, examining the value and methods of adding PET/CT data to the radiation therapy treatment algorithm. We will also discuss the various challenges and the areas where more evidence is required.

  9. Can FDG-PET assist in radiotherapy target volume definition of metastatic lymph nodes in head-and-neck cancer?

    International Nuclear Information System (INIS)

    Background and purpose: The role of FDG-PET in radiotherapy target volume definition of the neck was evaluated by comparing eight methods of FDG-PET segmentation to the current CT-based practice of lymph node assessment in head-and-neck cancer patients. Materials and methods: Seventy-eight head-and-neck cancer patients underwent coregistered CT- and FDG-PET scans. Lymph nodes were classified as 'enlarged' if the shortest axial diameter on CT was ≥10 mm, and as 'marginally enlarged' if it was 7-10 mm. Subsequently, lymph nodes were assessed on FDG-PET applying eight segmentation methods: visual interpretation (PETVIS), applying fixed thresholds at a standardized uptake value (SUV) of 2.5 and at 40% and 50% of the maximum signal intensity of the primary tumor (PETSUV, PET40%, PET50%) and applying a variable threshold based on the signal-to-background ratio (PETSBR). Finally, PET40%N, PET50%N and PETSBRN were acquired using the signal of the lymph node as the threshold reference. Results: Of 108 nodes classified as 'enlarged' on CT, 75% were also identified by PETVIS, 59% by PET40%, 43% by PET50% and 43% by PETSBR. Of 100 nodes classified as 'marginally enlarged', only a minority were visualized by FDG-PET. The respective numbers were 26%, 10%, 7% and 8% for PETVIS, PET40%, PET50% and PETSBR. PET40%N, PET50%N and PETSBRN, respectively, identified 66%, 82% and 96% of the PETVIS-positive nodes. Conclusions: Many lymph nodes that are enlarged and considered metastatic by standard CT-based criteria appear to be negative on FDG-PET scan. Alternately, a small proportion of marginally enlarged nodes are positive on FDG-PET scan. However, the results are largely dependent on the PET segmentation tool used, and until proper validation FDG-PET is not recommended for target volume definition of metastatic lymph nodes in routine practice.

  10. The study on the potential clinical value of sentinel lymphoscintigraphy in the radiation target volume design of internal mammary nodes

    International Nuclear Information System (INIS)

    Objective: We explored the potential clinical value of SPECT sentinel lymphoscintigraphy combined with a positional CT in defining the radiation target volume of internal mammary lymph nodes (IMN). Methods: (1) Forty breast cancer patients were enrolled, using 99Tcm-sulfur colloid (SC) as radiotracer and GE Millennium VG Hawkeye as imaging instrument. The depth ( distance from center of IMN to the surface of pectoralis major) and width (distance between the center of IMN and mid-sternal line) of each IMN were measured in the Hawkeye fusion images. (2) Hawkeye CT and diagnostic enhanced CT images of the same patients were analyzed, with the same reference points selected and their depths and widths measured. The location accuracy by the positional CT was evaluated. (3) Hawkeye positional CT and diagnostic CT scan were performed respectively using the CT quality control model attached to Hawkeye. The distances between the center of spheres on the Hawkeye CT and diagnostic CT images were measured, and then the data were compared and the model location accuracy of Hawkeye evaluated. Statistical comparison for the depth and the width between left and right IMN were performed with the t-test. Result: (1) Seventy IMN in 40 patients were studied. The depth was 1.10-3.99 cm with an average of 2.15 cm. The width was 1.52-6.59 cm with an average of 4.37 cm. The difference of depth between left and right IMN was not statistically significant (t= 1.1, P= 0.275), neither was the width (t=0.8, P=0.408). Only 11.4% (8/70) of the IMN and 10.0% (4/40) of the patients could fit the routine field. (2) CT position system of Hawkeye for localization of IMN was similar to that of diagnostic CT. Conclusion: IMN lymphoscintigraphy using Hawkeye CT positional system may be helpful for defining individual IMN radiation target volume. (authors)

  11. Dosimetric evaluation of planning target volume margin reduction for prostate cancer via image-guided intensity-modulated radiation therapy

    Science.gov (United States)

    Hwang, Taejin; Kang, Sei-Kwon; Cheong, Kwang-Ho; Park, Soah; Yoon, Jai-Woong; Han, Taejin; Kim, Haeyoung; Lee, Meyeon; Kim, Kyoung-Joo; Bae, Hoonsik; Suh, Tae-Suk

    2015-07-01

    The aim of this study was to quantitatively estimate the dosimetric benefits of the image-guided radiation therapy (IGRT) system for the prostate intensity-modulated radiation therapy (IMRT) delivery. The cases of eleven patients who underwent IMRT for prostate cancer without a prostatectomy at our institution between October 2012 and April 2014 were retrospectively analyzed. For every patient, clinical target volume (CTV) to planning target volume (PTV) margins were uniformly used: 3 mm, 5 mm, 7 mm, 10 mm, 12 mm, and 15 mm. For each margin size, the IMRT plans were independently optimized by one medical physicist using Pinnalce3 (ver. 8.0.d, Philips Medical System, Madison, WI) in order to maintain the plan quality. The maximum geometrical margin (MGM) for every CT image set, defined as the smallest margin encompassing the rectum at least at one slice, was between 13 mm and 26 mm. The percentage rectum overlapping PTV (%V ROV ), the rectal normal tissue complication probability (NTCP) and the mean rectal dose (%RD mean ) increased in proportion to the increase of PTV margin. However the bladder NTCP remained around zero to some extent regardless of the increase of PTV margin while the percentage bladder overlapping PTV (%V BOV ) and the mean bladder dose (%BD mean ) increased in proportion to the increase of PTV margin. Without relatively large rectum or small bladder, the increase observed for rectal NTCP, %RDmean and %BD mean per 1-mm PTV margin size were 1.84%, 2.44% and 2.90%, respectively. Unlike the behavior of the rectum or the bladder, the maximum dose on each femoral head had little effect on PTV margin. This quantitative study of the PTV margin reduction supported that IG-IMRT has enhanced the clinical effects over prostate cancer with the reduction of normal organ complications under the similar level of PTV control.

  12. Influence of experience and qualification on PET-based target volume delineation. When there is no expert - ask your colleague

    International Nuclear Information System (INIS)

    The integration of positron emission tomography (PET) information for target volume delineation in radiation treatment planning is routine in many centers. In contrast to automatic contouring, research on visual-manual delineation is scarce. The present study investigates the dependency of manual delineation on experience and qualification. A total of 44 international interdisciplinary observers each defined a [18F]fluorodeoxyglucose (FDG)-PET based gross tumor volume (GTV) using the same PET/CT scan from a patient with lung cancer. The observers were ''experts'' (E; n = 3), ''experienced interdisciplinary pairs'' (EP; 9 teams of radiation oncologist (RO) + nuclear medicine physician (NP)), ''single field specialists'' (SFS; n = 13), and ''students'' (S; n = 10). Five automatic delineation methods (AM) were also included. Volume sizes and concordance indices within the groups (pCI) and relative to the experts (eCI) were calculated. E (pCI = 0.67) and EP (pCI = 0.53) showed a significantly higher agreement within the groups as compared to SFS (pCI = 0.43, p = 0.03, and p = 0.006). In relation to the experts, EP (eCI = 0.55) showed better concordance compared to SFS (eCI = 0.49) or S (eCI = 0.47). The intermethod variability of the AM (pCI = 0.44) was similar to that of SFS and S, showing poorer agreement with the experts (eCI = 0.35). The results suggest that interdisciplinary cooperation could be beneficial for consistent contouring. Joint delineation by a radiation oncologist and a nuclear medicine physician showed remarkable agreement and better concordance with the experts compared to other specialists. The relevant intermethod variability of the automatic algorithms underlines the need for further standardization and optimization in this field. (orig.)

  13. Clipping of tumour resection margins allows accurate target volume delineation in head and neck cancer adjuvant radiation therapy

    International Nuclear Information System (INIS)

    Background: Accurate tumour bed localisation is a key requirement for adjuvant radiotherapy. A new procedure is described for head and neck cancer treatment that improves tumour bed localisation using titanium clips. Materials and methods: Following complete local excision of the primary tumour, the tumour bed was marked with titanium clips. Preoperative gross target volume (GTV) and postoperative tumour bed were examined and the distances between the centres of gravity were evaluated. Results: 49 patients with squamous cell carcinoma of the oral cavity were prospectively enrolled in this study. All patients underwent tumour resection, neck lymph node dissection and defect reconstruction in one stage. During surgery, 7–49 clips were placed in the resection cavity. Surgical clip insertion was successful in 88% (n = 43). Clip identification and tumour bed delineation was successful in all 43 patients. The overall distance between the centres of gravity of the preoperative tumour extension to the tumour bed was 0.9 cm. A significant relationship between the preoperative tumour extension and the postoperative tumour bed volume could be demonstrated. Conclusion: We demonstrate a precise delineation of the former tumour cavity. Improvements in tumour bed delineation allow an increase of accuracy for adjuvant treatment

  14. Impact of PET/CT on the treatment planning and target volume delineation of radiotherapy in the patients with non-small-cell lung cancer complicated by atelectasis

    International Nuclear Information System (INIS)

    Objective: To investigate the impact of PET/CT on the treatment planning and target volume delineation of radiotherapy in patients with NSCLC complicated by atelectasis. Methods: Pre-treatment PET/CT scans were performed in 36 patients with pathologically proven NSCLC complicated by atelectasis of different severity undergoing curative 3D-CRT planning. Clinical staging before and after PET/CT was compared and the change of treatment plan was evaluated. The target volumes were delineated by CT and PET/CT. Results: PET/CT results changed the clinical staging in 18 (50.0%, 18/36) patients. PET/CT identified distant metastatic diseases in 11 (30.6%, 11/36) patients, thus excluding their eligibility for curative 3D-CRT. Of these 11 patients, managements were changed to palliative radiotherapy in 3 patients, chemotherapy in 7 patients and best supportive therapy in 1 patient. In the 25 patients with curative 3D-CRT, PET/CT altered the radiotherapy volume in 21 cases, including 12 with volume reduction, 7 with volume enlargement and 2 with location change. Three patients were given additional conventional radiotherapy, since PET/CT indicated supraclavicular nodal metastases. In the 3 patients with palliative 3D-CRT, 2 had target volume reduction and 1 had target volume enlargement after PET/CT. Conclusions: PET/CT may play a role in the management of patients with NSCLC complicated by atelectasis. It is also helpful for accurate delineation of target volume in 3D-CRT treatment planning. (authors)

  15. Treating dose of target volume of nasopharyngeal carcinoma and contiguous organ at risk influenced by MRI and CT image difference in cranial base

    International Nuclear Information System (INIS)

    Objective: To study the treating dose of target volume of nasopharyngeal carcinoma (NPC) and contiguous organ at risk influenced by magnetic resonance imaging (MRI) and computed tomography (CT) Image difference in cranial base. Methods: 26 cases were performed from 101 patients of NPC with MRI and CT image difference in cranial base. We applied ARTP-TOP3D-TPS system to delineate target volume of NPC and contiguous organ at risk and develop the three-dimensional conformal radiotherapy (3-DCRT) plan, and compared the target volume of NPC by MRI (GTVMR) with the target volume of NPC by CT (GTVCT). Results: There was statistic difference between GTVMR (47.0±16.3) cm3 and GTVCT (31.6±10.0) cm3 (Z=4.462, P5 mean dose of brainstem, spinal cord, pituitary, temporal lobe and both eyes in MRI based plan were larger. There was no statistic difference in the mean dose of spinal cord between two plans. Conclusions: The dose of target volume in 3D-CRT plan based GTVMR is superior to GTVCT, but the dose of contiguous organ at risk in 3D-CRT plan based GTVMR is higher. (authors)

  16. Defining the Optimal Planning Target Volume in Image-Guided Stereotactic Radiosurgery of Brain Metastases: Results of a Randomized Trial

    Energy Technology Data Exchange (ETDEWEB)

    Kirkpatrick, John P., E-mail: john.kirkpatrick@dm.duke.edu [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States); Department of Surgery, Duke University, Durham, North Carolina (United States); Wang, Zhiheng [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States); Sampson, John H. [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States); Department of Surgery, Duke University, Durham, North Carolina (United States); McSherry, Frances; Herndon, James E. [Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina (United States); Allen, Karen J.; Duffy, Eileen [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States); Hoang, Jenny K. [Department of Radiology, Duke University, Durham, North Carolina (United States); Chang, Zheng; Yoo, David S.; Kelsey, Chris R.; Yin, Fang-Fang [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States)

    2015-01-01

    Purpose: To identify an optimal margin about the gross target volume (GTV) for stereotactic radiosurgery (SRS) of brain metastases, minimizing toxicity and local recurrence. Methods and Materials: Adult patients with 1 to 3 brain metastases less than 4 cm in greatest dimension, no previous brain radiation therapy, and Karnofsky performance status (KPS) above 70 were eligible for this institutional review board–approved trial. Individual lesions were randomized to 1- or 3- mm uniform expansion of the GTV defined on contrast-enhanced magnetic resonance imaging (MRI). The resulting planning target volume (PTV) was treated to 24, 18, or 15 Gy marginal dose for maximum PTV diameters less than 2, 2 to 2.9, and 3 to 3.9 cm, respectively, using a linear accelerator–based image-guided system. The primary endpoint was local recurrence (LR). Secondary endpoints included neurocognition Mini-Mental State Examination, Trail Making Test Parts A and B, quality of life (Functional Assessment of Cancer Therapy-Brain), radionecrosis (RN), need for salvage radiation therapy, distant failure (DF) in the brain, and overall survival (OS). Results: Between February 2010 and November 2012, 49 patients with 80 brain metastases were treated. The median age was 61 years, the median KPS was 90, and the predominant histologies were non–small cell lung cancer (25 patients) and melanoma (8). Fifty-five, 19, and 6 lesions were treated to 24, 18, and 15 Gy, respectively. The PTV/GTV ratio, volume receiving 12 Gy or more, and minimum dose to PTV were significantly higher in the 3-mm group (all P<.01), and GTV was similar (P=.76). At a median follow-up time of 32.2 months, 11 patients were alive, with median OS 10.6 months. LR was observed in only 3 lesions (2 in the 1 mm group, P=.51), with 6.7% LR 12 months after SRS. Biopsy-proven RN alone was observed in 6 lesions (5 in the 3-mm group, P=.10). The 12-month DF rate was 45.7%. Three months after SRS, no significant change in

  17. Defining the Optimal Planning Target Volume in Image-Guided Stereotactic Radiosurgery of Brain Metastases: Results of a Randomized Trial

    International Nuclear Information System (INIS)

    Purpose: To identify an optimal margin about the gross target volume (GTV) for stereotactic radiosurgery (SRS) of brain metastases, minimizing toxicity and local recurrence. Methods and Materials: Adult patients with 1 to 3 brain metastases less than 4 cm in greatest dimension, no previous brain radiation therapy, and Karnofsky performance status (KPS) above 70 were eligible for this institutional review board–approved trial. Individual lesions were randomized to 1- or 3- mm uniform expansion of the GTV defined on contrast-enhanced magnetic resonance imaging (MRI). The resulting planning target volume (PTV) was treated to 24, 18, or 15 Gy marginal dose for maximum PTV diameters less than 2, 2 to 2.9, and 3 to 3.9 cm, respectively, using a linear accelerator–based image-guided system. The primary endpoint was local recurrence (LR). Secondary endpoints included neurocognition Mini-Mental State Examination, Trail Making Test Parts A and B, quality of life (Functional Assessment of Cancer Therapy-Brain), radionecrosis (RN), need for salvage radiation therapy, distant failure (DF) in the brain, and overall survival (OS). Results: Between February 2010 and November 2012, 49 patients with 80 brain metastases were treated. The median age was 61 years, the median KPS was 90, and the predominant histologies were non–small cell lung cancer (25 patients) and melanoma (8). Fifty-five, 19, and 6 lesions were treated to 24, 18, and 15 Gy, respectively. The PTV/GTV ratio, volume receiving 12 Gy or more, and minimum dose to PTV were significantly higher in the 3-mm group (all P<.01), and GTV was similar (P=.76). At a median follow-up time of 32.2 months, 11 patients were alive, with median OS 10.6 months. LR was observed in only 3 lesions (2 in the 1 mm group, P=.51), with 6.7% LR 12 months after SRS. Biopsy-proven RN alone was observed in 6 lesions (5 in the 3-mm group, P=.10). The 12-month DF rate was 45.7%. Three months after SRS, no significant change in

  18. Methodologies for localizing loco-regional hypopharyngeal carcinoma recurrences in relation to FDG-PET positive and clinical radiation therapy target volumes

    International Nuclear Information System (INIS)

    Background. Focal methods to determine the source of recurrence are presented, tested for reproducibility and compared to volumetric approaches with respect to the number of recurrences ascribed to the FDG-PET positive and high dose volumes. Material and methods. Six patients treated for hypopharyngeal squamous cell carcinoma were extracted from archives. Inclusion criteria were: FDG-PET/CT for primary radiotherapy planning and clinical complete remission followed by loco-regional relapse. CT scan at the time of recurrence was also required. The recurrence volume was delineated in the follow-up scans by a radiologist. Putative points of origin (PO) of the recurrence were determined by two strategies 1) defined by an oncologist or 2) as the center-of-volume (COV) of the recurrence. The most likely recurrence point of origin on the treatment planning scan was also determined. All expert based points of origin were repeated to estimate reproducibility. The recurrence volume and PO were propagated to the treatment planning scan using a rigid transformation. Relations of the PO to target volumes, radiation doses and therapy-points-of-origin were quantified. For the volumetric methods, the overlap of the recurrence volume and target volumes was used to determine the source of the recurrence. Results. All recurrences were located in-field, but the volumetric approaches tended to designate fewer recurrences in the PET positive volume (25% for the 95% threshold, 95% confidence interval (CI):3-65%) than the observer-based methods (50% for the COV and both expert evaluations on the recurrence scan, 95% CI: 16-84%). The reproducibility of the expert POs is better on the recurrence scan than on the therapy scan. Conclusion. Volumetric approaches favor large target volumes as the source of the recurrence, thus underestimating the number of recurrences originating in the PET positive volume. Expert based and COV approaches on the recurrence scan are the most reproducible methods

  19. Comparison of Intensity-Modulated Radiotherapy Planning Based on Manual and Automatically Generated Contours Using Deformable Image Registration in Four-Dimensional Computed Tomography of Lung Cancer Patients

    International Nuclear Information System (INIS)

    Purpose: To evaluate the implications of differences between contours drawn manually and contours generated automatically by deformable image registration for four-dimensional (4D) treatment planning. Methods and Materials: In 12 lung cancer patients intensity-modulated radiotherapy (IMRT) planning was performed for both manual contours and automatically generated ('auto') contours in mid and peak expiration of 4D computed tomography scans, with the manual contours in peak inspiration serving as the reference for the displacement vector fields. Manual and auto plans were analyzed with respect to their coverage of the manual contours, which were assumed to represent the anatomically correct volumes. Results: Auto contours were on average larger than manual contours by up to 9%. Objective scores, D2% and D98% of the planning target volume, homogeneity and conformity indices, and coverage of normal tissue structures (lungs, heart, esophagus, spinal cord) at defined dose levels were not significantly different between plans (p = 0.22-0.94). Differences were statistically insignificant for the generalized equivalent uniform dose of the planning target volume (p = 0.19-0.94) and normal tissue complication probabilities for lung and esophagus (p = 0.13-0.47). Dosimetric differences >2% or >1 Gy were more frequent in patients with auto/manual volume differences ≥10% (p = 0.04). Conclusions: The applied deformable image registration algorithm produces clinically plausible auto contours in the majority of structures. At this stage clinical supervision of the auto contouring process is required, and manual interventions may become necessary. Before routine use, further investigations are required, particularly to reduce imaging artifacts

  20. Investigation on the role of integrated PET/MRI for target volume definition and radiotherapy planning in patients with high grade glioma

    International Nuclear Information System (INIS)

    Purpose: To evaluate the impact of fluid-attenuated-inversion-recovery MRI (FLAIR/MRI) and Carbon-11-labeled-methionine PET (11C-MET-PET) on high grade glioma (HGG) tumor volume delineation for radiotherapy planning. Material and methods: Sixty-nine patients with HGG were evaluated. The clinical target volumes (CTV1, generated by adding a 10 mm margin to FLAIRMRI area, CTV2 by adding a 20 mm margin to enhanced T1MRI) and biological target volume (BTV) were delineated on pre-operative MRI images and 11CMETPET respectively. Results: The overlap between CTV1 and CTV2 showed a low correlation between the two volumes with CTV1 not always fully included into the CTV2. In all cases the whole BTV was included into the CTV1, while in 35/69 patients (50%) part of BTV was outside the CTV2 despite larger margins were added. In all cases recurrences were within the CTV1 volume and in 19/38 (50%) partially outside the CTV2. In all patients relapse corresponded to the BTV area. Conclusions: Our data suggest that the target volume definition using FLAIR–MRI is more adequate compared to enhanced T1MRI. 11C-METPET uptake could help identify microscopic residual areas

  1. The morpho-PET with 18F-F.D.G. improves the definition of the target volume for the radiotherapy of child Hodgkin disease

    International Nuclear Information System (INIS)

    The objective is to study the impact of PET-T.D.M. images re-timing before chemotherapy with these ones of dosimetric scanner ( post chemotherapy) on the target volume determination and their inter observers variability among children receiving a closing radiotherapy for a Hodgkin disease. Conclusions: the inter observers variability for the clinical target volume (C.T.V.) definition is significantly reduced by the re-timing of initial PET-T.D.M. images on the ballistic scanner. This study illustrates the interest of the multidisciplinary cooperation between nuclear doctor and radiotherapist for the radiotherapy optimization. (N.C.)

  2. Consensus and controversies on delineation of radiotherapy target volume for patients with non-small cell lung cancer

    International Nuclear Information System (INIS)

    Objective: To investigate the consensus and controversies on delineation of radiotherapy target volume for patients with non-small cell lung cancer (NSCLC). Methods: Study questionnaires were designed by radiation oncologists in Peking University School of Oncology. The forms were sent through e mail to radiation oncologists in 10 radiation departments in China and 2 departments in US in November, 2007. The brief introduction and PET/CT digital data of one patient with NSCLC were sent to radiation oncologists in 10 departments in Beijing. On Jan. 12, 2008, the case discussion was held by more than 300 radiation oncologists from Beijing, Tianjin, Hebei, Liaoning Province and Inner Mongolia Autonomous Region. Results: All receivers of the questionnaire responded. The set up error was 5-7 mm. For patients with locally advanced NSCLC treated with radiotherapy concurrently with near full dose chemotherapy, 11 out of 12 responding departments defined planning target volume (PTV) of primary tumor as gross tumor volume(GTV) plus 6-8 mm plus set-up error and respiratory movements, and only one defined PTV as GTV plus set-up error and respiratory movements. For PTV of the mediastinal lymph nodes in the same patient, 9 out of 12 responding departments defined PTV as GTV plus 6-8 mm plus set-up error and respiratory movements, and 3 (of China) out of 12 defined PTV as GTV plus set-up error and respiratory movements. Stereotactic body radiotherapy with high fraction dose was used in 11 out of 12 responding departments with fraction dose varying from 6 to 20 Gy, including 6 of which defined PTV of primary tumor as GTV plus 6-8 mm plus respiratory movements and set-up error, and 5 defined PTV of early stage lung cancer as GTV plus respiratory movements and set-up error. The consensus on delineation of primary tumor of the case discussion was that the appropriate window width and window level were 1600 Hounsfield Units(HU) and -600 HU for lung window, and 400 HU and 20 HU for

  3. On the automated definition of mobile target volumes from 4D-CT images for stereotactic body radiotherapy

    International Nuclear Information System (INIS)

    Stereotactic body radiotherapy (SBRT) can be used to treat small lesions in the chest. A vacuum-based immobilization system is used in our clinic for SBRT, and a motion envelope is used in treatment planning. The purpose of this study is to automatically derive motion envelopes using deformable image registration of 4D-CT images, and to assess the effect of abdominal pressure on the motion envelopes. 4D-CT scans at ten phases were acquired prior to treatment for both free and restricted breathing using a vacuum-based immobilization system that includes an abdominal pressure pillow. To study the stability of the motion envelope over the course of treatment, a mid-treatment 4D-CT scan was obtained after delivery of the third fraction for two patients. The planning target volume excluding breathing motion (PTVex) was defined on the image set at full exhalation phase and transformed into all other phases using displacement maps from deformable image registration. The motion envelope was obtained as the union of PTVex masks of all phases. The ratios of the motion envelope to PTVex volume ranged from 1.3 to 2.5. When pressure was applied, the ratios were reduced by as much as 29% compared to free breathing for some patients, but increased by up to 9% for others. The abdominal pressure pillow has more motion restriction effects on the anterior/inferior region of the lung. For one of the two patients for whom the 4D-CT scan was repeated at mid-treatment, the motion envelope was reproducible. However, for the other patient the tumor location and lung motion pattern significantly changed due to changes in the anatomy surrounding the tumor during the course of treatment, indicating that an image-guided approach to SBRT may increase the efficacy of this treatment

  4. Residual Tumor After Neoadjuvant Chemoradiation Outside the Radiation Therapy Target Volume: A New Prognostic Factor for Survival in Esophageal Cancer

    International Nuclear Information System (INIS)

    Purpose/Objective(s): The aim of this study was to analyze the accuracy of gross tumor volume (GTV) delineation and clinical target volume (CTV) margins for neoadjuvant chemoradiation therapy (neo-CRT) in esophageal carcinoma at pathologic examination and to determine the impact on survival. Methods and Materials: The study population consisted of 63 esophageal cancer patients treated with neo-CRT. GTV and CTV borders were demarcated in situ during surgery on the esophagus, using anatomical reference points to provide accurate information regarding tumor location at pathologic evaluation. To identify prognostic factors for disease-free survival (DFS) and overall survival (OS), a Cox regression analysis was performed. Results: After resection, macroscopic residual tumor was found outside the GTV in 7 patients (11%). Microscopic residual tumor was located outside the CTV in 9 patients (14%). The median follow-up was 15.6 months. With multivariate analysis, only microscopic tumor outside the CTV (hazard ratio [HR], 4.96; 95% confidence interval [CI], 1.03-15.36), and perineural growth (HR, 5.77; 95% CI, 1.27-26.13) were identified as independent prognostic factors for OS. The 1-year OS was 20% for patients with tumor outside the CTV and 86% for those without (P<.01). For DFS, microscopic tumor outside the CTV (HR, 5.92; 95% CI, 1.89-18.54) and ypN+ (HR, 3.36; 95% CI, 1.33-8.48) were identified as independent adverse prognostic factors. The 1-year DFS was 23% versus 77% for patients with or without tumor outside the CTV (P<.01). Conclusions: Microscopic tumor outside the CTV is associated with markedly worse OS after neo-CRT. This may either stress the importance of accurate tumor delineation or reflect aggressive tumor behavior requiring new adjuvant treatment modalities

  5. Distance-to-Agreement Investigation of Tomotherapy's Bony Anatomy-Based Autoregistration and Planning Target Volume Contour-Based Optimization

    International Nuclear Information System (INIS)

    Purpose: To compare Tomotherapy's megavoltage computed tomography bony anatomy autoregistration with the best achievable registration, assuming no deformation and perfect knowledge of planning target volume (PTV) location. Methods and Materials: Distance-to-agreement (DTA) of the PTV was determined by applying a rigid-body shift to the PTV region of interest of the prostate from its reference position, assuming no deformations. Planning target volume region of interest of the prostate was extracted from the patient archives. The reference position was set by the 6 degrees of freedom (dof)—x, y, z, roll, pitch, and yaw—optimization results from the previous study at this institution. The DTA and the compensating parameters were calculated by the shift of the PTV from the reference 6-dof to the 4-dof—x, y, z, and roll—optimization. In this study, the effectiveness of Tomotherapy's 4-dof bony anatomy–based autoregistration was compared with the idealized 4-dof PTV contour-based optimization. Results: The maximum DTA (maxDTA) of the bony anatomy-based autoregistration was 3.2 ± 1.9 mm, with the maximum value of 8.0 mm. The maxDTA of the contour-based optimization was 1.8 ± 1.3 mm, with the maximum value of 5.7 mm. Comparison of Pearson correlation of the compensating parameters between the 2 4-dof optimization algorithms shows that there is a small but statistically significant correlation in y and z (0.236 and 0.300, respectively), whereas there is very weak correlation in x and roll (0.062 and 0.025, respectively). Conclusions: We find that there is an average improvement of approximately 1 mm in terms of maxDTA on the PTV going from 4-dof bony anatomy-based autoregistration to the 4-dof contour-based optimization. Pearson correlation analysis of the 2 4-dof optimizations suggests that uncertainties due to deformation and inadequate resolution account for much of the compensating parameters, but pitch variation also makes a statistically significant

  6. Setup Variations in Radiotherapy of Anal Cancer: Advantages of Target Volume Reduction Using Image-Guided Radiation Treatment

    International Nuclear Information System (INIS)

    Purpose: To define setup variations in the radiation treatment (RT) of anal cancer and to report the advantages of image-guided RT (IGRT) in terms of reduction of target volume and treatment-related side effects. Methods and Materials: Twelve consecutive patients with anal cancer treated by combined chemoradiation by use of helical tomotherapy from March 2007 to November 2008 were selected. With patients immobilized and positioned in place, megavoltage computed tomography (MVCT) scans were performed before each treatment and were automatically registered to planning CT scans. Patients were shifted per the registration data and treated. A total of 365 MVCT scans were analyzed. The primary site received a median dose of 55 Gy. To evaluate the potential dosimetric advantage(s) of IGRT, cases were replanned according to Radiation Therapy Oncology Group 0529, with and without adding recommended setup variations from the current study. Results: Significant setup variations were observed throughout the course of RT. The standard deviations for systematic setup correction in the anterior–posterior (AP), lateral, and superior–inferior (SI) directions and roll rotation were 1.1, 3.6, and 3.2 mm, and 0.3°, respectively. The average random setup variations were 3.8, 5.5, and 2.9 mm, and 0.5°, respectively. Without daily IGRT, margins of 4.9, 11.1, and 8.5 mm in the AP, lateral, and SI directions would have been needed to ensure that the planning target volume (PTV) received ≥95% of the prescribed dose. Conversely, daily IGRT required no extra margins on PTV and resulted in a significant reduction of V15 and V45 of intestine and V10 of pelvic bone marrow. Favorable toxicities were observed, except for acute hematologic toxicity. Conclusions: Daily MVCT scans before each treatment can effectively detect setup variations and thereby reduce PTV margins in the treatment of anal cancer. The use of concurrent chemotherapy and IGRT provided favorable toxicities, except for

  7. Impact of planning target volume margins and rectal distention on biochemical failure in image-guided radiotherapy of prostate cancer

    International Nuclear Information System (INIS)

    Background and purpose: A previous study in our department demonstrated the negative impact on freedom from biochemical failure (FFBF) of using too narrow planning target volume (PTV) margins during prostate image-guided radiotherapy (IGRT). Here, we investigated the impact of appropriate PTV margins and rectal distention on FFBF. Methods and materials: A total of 50 T1-T3N0M0 prostate cancer patients were treated with daily IGRT by implanted markers. In the first 25 patients, PTV margins were 3 mm laterolateral, 5 mm anterioposterior and 4 mm craniocaudal. The subsequent 25 patients were treated with isotropic margins of 6 mm. The rectal cross-sectional area (CSA) was determined on the planning CT. Median follow-up was 61 months. Results: The overall 5-year FFBF was 83%. A 6 mm PTV margin was related to increased 5-year FFBF on univariate analysis (96% vs 74% with the tighter PTV margins, p = 0.04). The 5-year FFBF of patients with a rectal distention on the planning CT was worse compared to those with limited rectal filling (75% for CSA ⩾ 9 cm2 vs 89% for CSA < 9 cm2, p = 0.02), which remained significant on multivariate analysis (p = 0.04). Conclusion: This retrospective study illustrated the positive impact of PTV margin adaptation and addressed the importance of avoiding rectal distention at time of the planning CT

  8. Extension of Local Disease in Nasopharyngeal Carcinoma Detected by Magnetic Resonance Imaging: Improvement of Clinical Target Volume Delineation

    International Nuclear Information System (INIS)

    Purpose: To define by MRI the local extension patterns in patients presenting with nasopharyngeal carcinoma (NPC) and to improve clinical target volume delineation. Methods and Materials: Consecutive patients (N = 943) with newly diagnosed and untreated NPC were included in this study. All patients underwent MRI of the nasopharynx and neck, which was reviewed by two radiologists. Results: According to the incidence rates of tumor invasion, the anatomic sites surrounding the nasopharynx were initially classified into three risk grades: high risk (≥ 35%), medium risk (≥ 5-35%), and low risk (< 5%). Incidence rates of tumor invasion into anatomic sites at medium risk were increased, reaching 55.2%, when adjacent high-risk anatomic sites were involved. However, the rates were substantially lower, mostly < 10%, when adjacent high-risk sites were not involved. The incidence rates of concurrent tumor invasion into bilateral sites were < 10%, except in the case of prevertebral muscle involvement (13.1%). Among the 178 incidences of cavernous sinus invasion, there were often two or more simultaneous infiltration routes (60.6%); when only one route was involved, the foramen ovale was the most common (26.4%). Conclusions: In patients presenting with NPC, local disease spreads stepwise from proximal sites to more distal sites. Tumors extend quickly through privileged pathways such as neural foramina. The anatomic sites surrounding the nasopharynx are at low risk of concurrent bilateral tumor invasion. Selective radiotherapy of the local disease in NPC may be feasible.

  9. A dimensionless dynamic contrast enhanced MRI parameter for intra-prostatic tumour target volume delineation: initial comparison with histology

    Science.gov (United States)

    Hrinivich, W. Thomas; Gibson, Eli; Gaed, Mena; Gomez, Jose A.; Moussa, Madeleine; McKenzie, Charles A.; Bauman, Glenn S.; Ward, Aaron D.; Fenster, Aaron; Wong, Eugene

    2014-03-01

    Purpose: T2 weighted and diffusion weighted magnetic resonance imaging (MRI) show promise in isolating prostate tumours. Dynamic contrast enhanced (DCE)-MRI has also been employed as a component in multi-parametric tumour detection schemes. Model-based parameters such as Ktrans are conventionally used to characterize DCE images and require arterial contrast agent (CR) concentration. A robust parameter map that does not depend on arterial input may be more useful for target volume delineation. We present a dimensionless parameter (Wio) that characterizes CR wash-in and washout rates without requiring arterial CR concentration. Wio is compared to Ktrans in terms of ability to discriminate cancer in the prostate, as demonstrated via comparison with histology. Methods: Three subjects underwent DCE-MRI using gadolinium contrast and 7 s imaging temporal resolution. A pathologist identified cancer on whole-mount histology specimens, and slides were deformably registered to MR images. The ability of Wio maps to discriminate cancer was determined through receiver operating characteristic curve (ROC) analysis. Results: There is a trend that Wio shows greater area under the ROC curve (AUC) than Ktrans with median AUC values of 0.74 and 0.69 respectively, but the difference was not statistically significant based on a Wilcoxon signed-rank test (p = 0.13). Conclusions: Preliminary results indicate that Wio shows potential as a tool for Ktrans QA, showing similar ability to discriminate cancer in the prostate as Ktrans without requiring arterial CR concentration.

  10. Target volume for postoperative radiotherapy in non-small cell lung cancer: Results from a prospective trial

    International Nuclear Information System (INIS)

    Background and purpose: A previous prospective trial reported that three-dimensional conformal postoperative radiotherapy (PORT) for pN2 NSCLC patients using a limited clinical target volume (CTV) had a late morbidity rate and pulmonary function that did not differ from those observed in pN1 patients treated with surgery without PORT. The aim of this study was to assess locoregional control and localization of failure in patients treated with PORT. Materials and methods: The pattern of locoregional failure was evaluated retrospectively in 151 of 171 patients included in the PORT arm. The CTV included the involved lymph node stations and those with a risk of invasion >10%. Competing risk analysis was used to assess the incidence of locoregional failure and its location outside the CTV. Results: Overall survival at 5 years was 27.1% with a median follow-up of 67 months for 40 living patients. The 5-year cumulative incidence of locoregional failure was 19.4% (95% CI: 18.2–20.5%) including a failure rate of 2% (95% CI: 0–17%) in locations outside or at the border of the CTV. Conclusions: The use of limited CTV was associated with acceptable risk of geographic miss. Overall locoregional control was similar to that reported by other studies using PORT for pN2 patients

  11. Influence of experience and qualification on PET-based target volume delineation. When there is no expert - ask your colleague

    Energy Technology Data Exchange (ETDEWEB)

    Doll, C.; Grosu, A.L.; Nestle, U. [University Medical Center Freiburg, Radiation Oncology Department, Freiburg/Breisgau (Germany); Duncker-Rohr, V. [University Medical Center Freiburg, Radiation Oncology Department, Freiburg/Breisgau (Germany); Ortenau Clinical Center Offenburg, Radiation Oncology Department, Offenburg (Germany); Ruecker, G. [University of Freiburg, Institute of Medical Biometry und Medical Informatics, Freiburg (Germany); Mix, M. [University Medical Center Freiburg, Nuclear Medicine Department, Freiburg (Germany); MacManus, M. [University of Melbourne, The Sir Peter MacCallum Department of Oncology, Melbourne (Australia); Ruysscher, D. de [University Hospital Leuven/KU Leuven, Department of Radiation Oncology, Leuven (Belgium); Vogel, W. [Antoni van Leeuwenhoek Hospital, Department of Nuclear Medicine, The Netherlands Cancer Institute, Amsterdam (Netherlands); Eriksen, J.G. [Odense University Hospital, Department of Oncology, Odense (Denmark); Oyen, W. [Radboud University Nijmegen Medical Center, Department of Nuclear Medicine, Nijmegen (Netherlands); Weber, W. [University Medical Center Freiburg, Nuclear Medicine Department, Freiburg (Germany); Memorial Sloan-Kettering Cancer Center, Department of Radiology/Molecular Imaging and Therapy Service, New York (United States)

    2014-06-15

    The integration of positron emission tomography (PET) information for target volume delineation in radiation treatment planning is routine in many centers. In contrast to automatic contouring, research on visual-manual delineation is scarce. The present study investigates the dependency of manual delineation on experience and qualification. A total of 44 international interdisciplinary observers each defined a [{sup 18}F]fluorodeoxyglucose (FDG)-PET based gross tumor volume (GTV) using the same PET/CT scan from a patient with lung cancer. The observers were ''experts'' (E; n = 3), ''experienced interdisciplinary pairs'' (EP; 9 teams of radiation oncologist (RO) + nuclear medicine physician (NP)), ''single field specialists'' (SFS; n = 13), and ''students'' (S; n = 10). Five automatic delineation methods (AM) were also included. Volume sizes and concordance indices within the groups (pCI) and relative to the experts (eCI) were calculated. E (pCI = 0.67) and EP (pCI = 0.53) showed a significantly higher agreement within the groups as compared to SFS (pCI = 0.43, p = 0.03, and p = 0.006). In relation to the experts, EP (eCI = 0.55) showed better concordance compared to SFS (eCI = 0.49) or S (eCI = 0.47). The intermethod variability of the AM (pCI = 0.44) was similar to that of SFS and S, showing poorer agreement with the experts (eCI = 0.35). The results suggest that interdisciplinary cooperation could be beneficial for consistent contouring. Joint delineation by a radiation oncologist and a nuclear medicine physician showed remarkable agreement and better concordance with the experts compared to other specialists. The relevant intermethod variability of the automatic algorithms underlines the need for further standardization and optimization in this field. (orig.) [German] Die Daten aus der Positronenemissionstomographie (PET) werden in vielen Kliniken routinemaessig zur

  12. Delineation of target volumes and organs at risk in adjuvant radiotherapy of early breast cancer: national guidelines and contouring atlas by the Danish Breast Cancer Cooperative Group

    DEFF Research Database (Denmark)

    Nielsen, Mette H; Berg, Martin; Pedersen, Anders N;

    2013-01-01

    During the past decade planning of adjuvant radiotherapy (RT) of early breast cancer has changed from two-dimensional (2D) to 3D conformal techniques. In the planning computerised tomography (CT) scan both the targets for RT and the organs at risk (OARs) are visualised, enabling an increased focu...... on target dose coverage and homogeneity with only minimal dose to the OARs. To ensure uniform RT in the national prospective trials of the Danish Breast Cancer Cooperative Group (DBCG), a national consensus for the delineation of clinical target volumes (CTVs) and OARs was required....

  13. A consensus-based guideline defining the clinical target volume for pelvic lymph nodes in external beam radiotherapy for uterine cervical cancer

    International Nuclear Information System (INIS)

    The objective of this study was to develop a consensus-based guideline as well as an atlas defining pelvic nodal clinical target volumes in external beam radiotherapy for uterine cervical cancer. A working subgroup to establish the consensus-based guideline on clinical target volumes for uterine cervical cancer was formulated by the Radiation Therapy Study Group of the Japan Clinical Oncology Group in July 2008. The working subgroup consisted of seven radiation oncologists. The process resulting in the consensus included a comparison of contouring on CT images among the members, reviewing of published textbooks and the relevant literature and a distribution analysis of metastatic nodes on computed tomography/magnetic resonance imaging of actual patients. The working subgroup defined the pelvic nodal clinical target volumes for cervical cancer and developed an associated atlas. As a basic criterion, the lymph node clinical target volume was defined as the area encompassed by a 7 mm margin around the applicable pelvic vessels. Modifications were made in each nodal area to cover adjacent adipose tissues at risk of microscopic nodal metastases. Although the bones and muscles were excluded, the bowel was not routinely excluded in the definition. Each of the following pelvic node regions was defined: common iliac, external iliac, internal iliac, obturator and presacral. Anatomical structures bordering each lymph node region were defined for six directions; anterior, posterior, lateral, medial, cranial and caudal. Drafts of the definition and the atlas were reviewed by members of the JCOG Gynecologic Cancer Study Group (GCSG). We developed a consensus-based guideline defining the pelvic node clinical target volumes that included an atlas. The guideline will be continuously updated to reflect the ongoing changes in the field. (author)

  14. Reduce in Variation and Improve Efficiency of Target Volume Delineation by a Computer-Assisted System Using a Deformable Image Registration Approach

    International Nuclear Information System (INIS)

    Purpose: To determine whether a computer-assisted target volume delineation (CAT) system using a deformable image registration approach can reduce the variation of target delineation among physicians with different head and neck (HN) IMRT experiences and reduce the time spent on the contouring process. Materials and Methods: We developed a deformable image registration method for mapping contours from a template case to a patient case with a similar tumor manifestation but different body configuration. Eight radiation oncologists with varying levels of clinical experience in HN IMRT performed target delineation on two HN cases, one with base-of-tongue (BOT) cancer and another with nasopharyngeal cancer (NPC), by first contouring from scratch and then by modifying the contours deformed by the CAT system. The gross target volumes were provided. Regions of interest for comparison included the clinical target volumes (CTVs) and normal organs. The volumetric and geometric variation of these regions of interest and the time spent on contouring were analyzed. Results: We found that the variation in delineating CTVs from scratch among the physicians was significant, and that using the CAT system reduced volumetric variation and improved geometric consistency in both BOT and NPC cases. The average timesaving when using the CAT system was 26% to 29% for more experienced physicians and 38% to 47% for the less experienced ones. Conclusions: A computer-assisted target volume delineation approach, using a deformable image-registration method with template contours, was able to reduce the variation among physicians with different experiences in HN IMRT while saving contouring time

  15. Definition of the planning target volume of organs at risk (planning organ at risk volume, PRV) in case of radiotherapy of the ORL sphere; Definition d'un volume cible previsionnel d'organe a risque (Planning organ at risk volume, PRV) en cas de radiotherapie de la sphere ORL

    Energy Technology Data Exchange (ETDEWEB)

    Louvel, G.; Le Prise, E.; Williaume, D.; De Crevoisier, R. [Centre Eugene-Marquis, 35 - Rennes (France); Cazoulat, G.; Lafond, C.; Simon, A.; Haigron, P.; De Crevoisier, R. [Universite de Rennes 1 LTSI, 35 - Rennes (France); Inserm U642, 35 - Rennes (France); Li, B.S. [Shandong Cancer Hospital, Jinan (China); Boisselier, P. [Centre Val d' Aurelle, 34 - Montpellier (France)

    2010-10-15

    The authors report a study which aimed at quantifying anatomic variations of organs at risk and their dosimetric impact, and at computing appropriate margins around organs at risk to generate planning target volumes of organs at risk, representative of the dose delivered to organs at risk. Nine patients have been treated for a locally advanced ORL cancer by a concomitant combination of radiotherapy and chemotherapy, with weekly scanographies during the radiotherapy. Registration has been successfully performed according to three bone references. Volume modifications and motions have been computed to define the margins around three organs at risk. Short communication

  16. SU-E-J-192: Verification of 4D-MRI Internal Target Volume Using Cine MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lafata, K; Czito, B; Palta, M; Bashir, M; Yin, F; Cai, J [Duke University Medical Center, Durham, NC (United States)

    2014-06-01

    Purpose: To investigate the accuracy of 4D-MRI in determining the Internal Target Volume (ITV) used in radiation oncology treatment planning of liver cancers. Cine MRI is used as the standard baseline in establishing the feasibility and accuracy of 4D-MRI tumor motion within the liver. Methods: IRB approval was obtained for this retrospective study. Analysis was performed on MR images from four patients receiving external beam radiation therapy for liver cancer at our institution. Eligible patients received both Cine and 4D-MRI scans before treatment. Cine images were acquired sagittally in real time at a slice bisecting the tumor, while 4D images were acquired volumetrically. Cine MR DICOM headers were manipulated such that each respiratory frame was assigned a unique slice location. This approach permitted the treatment planning system (Eclipse, Varian Medical Systems) to recognize a complete respiratory cycle as a “volume”, where the gross tumor was contoured temporally. Software was developed to calculate the union of all frame contours in the structure set, resulting in the corresponding plane of the ITV projecting through the middle of the tumor, defined as the Internal Target Area (ITA). This was repeated for 4D-MRI, at the corresponding slice location, allowing a direct comparison of ITAs obtained from each modality. Results: Four patients have been analyzed. ITAs contoured from 4D-MRI correlate with contours from Cine MRI. The mean error of 4D values relative to Cine values is 7.67 +/− 2.55 %. No single ITA contoured from 4D-MRI demonstrated more than 10.5 % error compared to its Cine MRI counterpart. Conclusion: Motion management is a significant aspect of treatment planning within dynamic environments such as the liver, where diaphragmatic and cardiac activity influence plan accuracy. This small pilot study suggests that 4D-MRI based ITA measurements agree with Cine MRI based measurements, an important step towards clinical implementation. NIH 1R21

  17. Mapping Patterns of Ipsilateral Supraclavicular Nodal Metastases in Breast Cancer: Rethinking the Clinical Target Volume for High-risk Patients

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Hao [Department of Radiation Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Wang, Shu-Lian, E-mail: wsl20040118@yahoo.com [Department of Radiation Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Li, Jing; Xue, Mei; Xiong, Zu-Kun [Department of Radiology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Jin, Jing; Wang, Wei-Hu; Song, Yong-Wen; Liu, Yue-Ping; Ren, Hua; Fang, Hui; Yu, Zi-Hao; Liu, Xin-Fan [Department of Radiation Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Li, Ye-Xiong, E-mail: yexiong12@163.com [Department of Radiation Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China)

    2015-10-01

    Purpose: To map the location of metastatic supraclavicular (SCV) lymph nodes (LNMs) in breast cancer patients with SCV node involvement and determine whether and where the radiation therapy clinical target volume (CTV) of this region could be modified in high-risk subsets. Methods and Materials: Fifty-five patients with metastatic SCV LNMs were eligible for geographic mapping and atlas coverage analysis. All LNMs and their epicenters were registered proportionally by referencing the surrounding landmarks onto simulation computed tomography images of a standard patient. CTVs based on selected SCV atlases, including the one by the Radiation Therapy Oncology Group (RTOG) were contoured. A modified SCV CTV was tried and shown to have better involved-node coverage and thus theoretically improved prophylaxis in this setting. Results: A total of 50 (91%) and 45 (81.8%) patients had LNMs in the medial and lateral SCV subregions, respectively. Also, 36 patients (65.5%) had LNMs located at the junction of the jugular-subclavian veins. All nodes were covered in only 25.5% to 41.8% of patients by different atlases. The RTOG atlas covered all nodes in 25.5% of patients. Stratified by the nodes in all the patients as a whole, 49.2% to 81.3% were covered, and the RTOG atlas covered 62.6%. The lateral and posterior borders were the most overlooked locations. Modification by extending the borders to natural anatomic barriers allowed the new CTV to cover all the nodes in 81.8% of patients and encompass 96.1% of all the nodes. Conclusions: According to the distribution of SCV LNMs, the extent of existing atlases might not be adequate for potential metastatic sites in certain groups of patients. The extension of the lateral and posterior CTV borders in high-risk or recurrent patients might be a reasonable approach for increasing coverage. However, additional data in more homogeneous populations with localized disease are needed before routine application.

  18. Mapping Patterns of Ipsilateral Supraclavicular Nodal Metastases in Breast Cancer: Rethinking the Clinical Target Volume for High-risk Patients

    International Nuclear Information System (INIS)

    Purpose: To map the location of metastatic supraclavicular (SCV) lymph nodes (LNMs) in breast cancer patients with SCV node involvement and determine whether and where the radiation therapy clinical target volume (CTV) of this region could be modified in high-risk subsets. Methods and Materials: Fifty-five patients with metastatic SCV LNMs were eligible for geographic mapping and atlas coverage analysis. All LNMs and their epicenters were registered proportionally by referencing the surrounding landmarks onto simulation computed tomography images of a standard patient. CTVs based on selected SCV atlases, including the one by the Radiation Therapy Oncology Group (RTOG) were contoured. A modified SCV CTV was tried and shown to have better involved-node coverage and thus theoretically improved prophylaxis in this setting. Results: A total of 50 (91%) and 45 (81.8%) patients had LNMs in the medial and lateral SCV subregions, respectively. Also, 36 patients (65.5%) had LNMs located at the junction of the jugular-subclavian veins. All nodes were covered in only 25.5% to 41.8% of patients by different atlases. The RTOG atlas covered all nodes in 25.5% of patients. Stratified by the nodes in all the patients as a whole, 49.2% to 81.3% were covered, and the RTOG atlas covered 62.6%. The lateral and posterior borders were the most overlooked locations. Modification by extending the borders to natural anatomic barriers allowed the new CTV to cover all the nodes in 81.8% of patients and encompass 96.1% of all the nodes. Conclusions: According to the distribution of SCV LNMs, the extent of existing atlases might not be adequate for potential metastatic sites in certain groups of patients. The extension of the lateral and posterior CTV borders in high-risk or recurrent patients might be a reasonable approach for increasing coverage. However, additional data in more homogeneous populations with localized disease are needed before routine application

  19. What's new in target volume definition for radiologists in ICRU Report 71? How can the ICRU volume definitions be integrated in clinical practice?

    DEFF Research Database (Denmark)

    Berthelsen, Anne Kiil; Dobbs, Jane; Kjellén, Elisabeth;

    2007-01-01

    The optimal definition of the size, shape and location of gross tumour volume is one of the most important steps in the planning of radiation therapy, and necessitates a proper understanding of the procedure from both the oncologic radiologist and the radiation oncologist. This overview reports on...

  20. Quantitative evaluation of cone-beam computed tomography in target volume definition for offline image-guided radiation therapy of prostate cancer

    International Nuclear Information System (INIS)

    Purpose: To quantitatively evaluate cone-beam CT (CBCT) in target volume definition in an offline image guidance environment. Methods and materials: Fifteen patients each with five helical CTs (HCT) and eight CBCTs were included. A single physician manually delineated prostate and seminal vesicles (SVs) on each CT. The clinical target volume (CTV) was prostate for low risk group (G1), plus SVs for intermediate risk group (G2). The internal target volumes (ITVs) on CBCT (ITVCBCT) were constructed and compared with ITVHCT. The following comparisons were performed: CTV and ITV in HCT and CBCT; similarity of ITVs using overlap index (OI); surface differences between ITVs; quality assurance of ITVCBCT using CTV from weekly CBCT; and dosimetric evaluations of ITVHCT coverage on plans from ITVCBCT. Results: There was no statistical significant difference of CTV or ITV. The ITV OIs were 91%/88% for G1/G2 patients. They improved significantly with 1-2 mm margins. Therefore, the ITVs were mostly within 2 mm. The CTVs from weekly CBCT had >95% overlap with ITVCBCT. The ITV dose differences (D95, and Dmean) were <0.3%. Conclusions: It is feasible to use CBCT for target definition in offline image guidance, thereby eliminating the separate helical CT scan process.

  1. Impact of 18F-FDG PET/CT on target volume delineation in recurrent or residual gynaecologic carcinoma

    OpenAIRE

    Vees Hansjörg; Casanova Nathalie; Zilli Thomas; Imperiano Hestia; Ratib Osman; Popowski Youri; Wang Hui; Zaidi Habib; Miralbell Raymond

    2012-01-01

    Abstract Background To evaluate the impact of 18F-FDG PET/CT on target volume delineation in gynaecological cancer. Methods F-FDG PET/CT based RT treatment planning was performed in 10 patients with locally recurrent (n = 5) or post-surgical residual gynaecological cancer (n = 5). The gross tumor volume (GTV) was defined by 4 experienced radiation oncologists first using contrast enhanced CT (GTVCT) and secondly using the fused 18F-FDG PET/CT datasets (GTVPET/CT). In addition, the GTV was del...

  2. Influence of experience and qualification on PET-based target volume delineation. When there is no expert--ask your colleague

    DEFF Research Database (Denmark)

    Doll, C; Duncker-Rohr, V; Rücker, G;

    2014-01-01

    BACKGROUND AND PURPOSE: The integration of positron emission tomography (PET) information for target volume delineation in radiation treatment planning is routine in many centers. In contrast to automatic contouring, research on visual-manual delineation is scarce. The present study investigates...... observers were "experts" (E; n = 3), "experienced interdisciplinary pairs" (EP; 9 teams of radiation oncologist (RO) + nuclear medicine physician (NP)), "single field specialists" (SFS; n = 13), and "students" (S; n = 10). Five automatic delineation methods (AM) were also included. Volume sizes and...

  3. Comparison of Five Segmentation Tools for 18F-Fluoro-Deoxy-Glucose-Positron Emission Tomography-Based Target Volume Definition in Head and Neck Cancer

    International Nuclear Information System (INIS)

    Purpose: Target-volume delineation for radiation treatment to the head and neck area traditionally is based on physical examination, computed tomography (CT), and magnetic resonance imaging. Additional molecular imaging with 18F-fluoro-deoxy-glucose (FDG)-positron emission tomography (PET) may improve definition of the gross tumor volume (GTV). In this study, five methods for tumor delineation on FDG-PET are compared with CT-based delineation. Methods and Materials: Seventy-eight patients with Stages II-IV squamous cell carcinoma of the head and neck area underwent coregistered CT and FDG-PET. The primary tumor was delineated on CT, and five PET-based GTVs were obtained: visual interpretation, applying an isocontour of a standardized uptake value of 2.5, using a fixed threshold of 40% and 50% of the maximum signal intensity, and applying an adaptive threshold based on the signal-to-background ratio. Absolute GTV volumes were compared, and overlap analyses were performed. Results: The GTV method of applying an isocontour of a standardized uptake value of 2.5 failed to provide successful delineation in 45% of cases. For the other PET delineation methods, volume and shape of the GTV were influenced heavily by the choice of segmentation tool. On average, all threshold-based PET-GTVs were smaller than on CT. Nevertheless, PET frequently detected significant tumor extension outside the GTV delineated on CT (15-34% of PET volume). Conclusions: The choice of segmentation tool for target-volume definition of head and neck cancer based on FDG-PET images is not trivial because it influences both volume and shape of the resulting GTV. With adequate delineation, PET may add significantly to CT- and physical examination-based GTV definition

  4. Impact of 18FDG-PET/CT on biological target volume (BTV) definition for treatment planning for non-small cell lung cancer patients

    Science.gov (United States)

    Devic, Slobodan; Tomic, Nada; Faria, Sergio; Dean, Geoffrey; Lisbona, Robert; Parker, William; Kaufman, Chris; Podgorsak, Ervin B.

    2007-02-01

    This work represents our effort to test feasibility of FDG-based PET/CT on target volume delineation in radiotherapy treatment planning of NSCLC patients. Different methods have been developed to enable more precise target outlining using PET: Qualitative Visual Method, CTV=2.5 SUV units, linear SUV threshold function method, and CTV=40% Iso of Maximum Uptake Value. We are proposing reconstruction of three biological target volumes: necrotic BTV (same as PTV created by radiation oncologist using CT data), proliferating BTV (based on PET signal to background ratio 1:3) and hypoxic BTV (based on PET signal to background ratio of 1:19). Two IMRT plans were created and compared to the conventional treatment plan: "conservative" IMRT plan delivers 52.5 Gy to the necrotic BTV and 65 Gy to the hypoxic BTV; "radical" IMRT plan delivers 30 Gy to necrotic BTV, 52.5 Gy to proliferating BTV and 65 Gy to hypoxic BTV. Use of BTVs in IMRT plans is attractive because it increases dose to targets considered to need higher doses. It reduces considerably dose to heart and spinal cord, organs considered to limit dose escalation approaches in NSCLC treatment. "Conservative" IMRT approach can be understood as a PET/CT-based concomitant boost to the tumor expressing the highest FDG uptake. "Radical" plan implies deviation from the traditional uniform dose target coverage approach, with the intention of achieving better surrounding tissue sparing and ultimately allowing for dose escalation protocols relying on biologically based treatment planning.

  5. Impact of 18FDG-PET/CT on biological target volume (BTV) definition for treatment planning for non-small cell lung cancer patients

    International Nuclear Information System (INIS)

    This work represents our effort to test feasibility of FDG-based PET/CT on target volume delineation in radiotherapy treatment planning of NSCLC patients. Different methods have been developed to enable more precise target outlining using PET: Qualitative Visual Method, CTV=2.5 SUV units, linear SUV threshold function method, and CTV=40% Iso of Maximum Uptake Value. We are proposing reconstruction of three biological target volumes: necrotic BTV (same as PTV created by radiation oncologist using CT data), proliferating BTV (based on PET signal to background ratio 1:3) and hypoxic BTV (based on PET signal to background ratio of 1:19). Two IMRT plans were created and compared to the conventional treatment plan: 'conservative' IMRT plan delivers 52.5 Gy to the necrotic BTV and 65 Gy to the hypoxic BTV; 'radical' IMRT plan delivers 30 Gy to necrotic BTV, 52.5 Gy to proliferating BTV and 65 Gy to hypoxic BTV. Use of BTVs in IMRT plans is attractive because it increases dose to targets considered to need higher doses. It reduces considerably dose to heart and spinal cord, organs considered to limit dose escalation approaches in NSCLC treatment. 'Conservative' IMRT approach can be understood as a PET/CT-based concomitant boost to the tumor expressing the highest FDG uptake. 'Radical' plan implies deviation from the traditional uniform dose target coverage approach, with the intention of achieving better surrounding tissue sparing and ultimately allowing for dose escalation protocols relying on biologically based treatment planning

  6. Photon dosimetry methods outside the target volume in radiation therapy: Optically stimulated luminescence (OSL), thermoluminescence (TL) and radiophotoluminescence (RPL) dosimetry

    International Nuclear Information System (INIS)

    Dosimetry methods outside the target volume are still not well established in radiotherapy. Luminescence detectors due to their small dimensions, very good sensitivity, well known dose and energy response are considered as an interesting approach in verification of doses outside the treated region. The physical processes of thermoluminescence (TL), radiophotoluminescence (RPL) and optically stimulated luminescence (OSL) are very similar and can be described in terms of the energy band model of electron-hole production following irradiation. This work is a review of the main dosimetric characteristics of luminescence detectors which were used in experiments performed by EURADOS Working Group 9 for in-phantom measurements of secondary radiation (scattered and leakage photons). TL LiF:Mg,Ti detectors type MTS-7 (IFJ PAN, Poland), types TLD-100 and TLD-700 (Harshaw), OSL Al2O3:C detectors type nanoDot™ (Landauer Inc.) and RPL rod glass elements type GD-352M (Asahi Techno Glass Coorporation) are described. The main characteristics are discussed, together with the readout and calibration procedures which lead to a determination of absorbed dose to water. All dosimeter types used show very good uniformity, batch reproducibility and homogeneity. For improved accuracy, individual sensitivity correction factors should be applied for TL and OSL dosimeters while for RPL dosimeters there is no need for individual sensitivity corrections. The dose response of all dosimeters is linear for a wide range of doses. The energy response of GD-352M type dosimeters (with Sn filter) used for out-of-field measurements is flat for medium and low energy X-rays. The energy dependence for TLDs is low across the range of photon energies used and the energy correction was neglected. A significant over response of Al2O3:C OSLDs irradiated in kilovoltage photon beams was taken into account. The energy correction factor fen was calculated by using the 2006 PENELOPE Monte Carlo code. With suitable

  7. A preliminary study of three-dimensional conformal radiotherapy with different clinical target volumes for esophageal cancer

    International Nuclear Information System (INIS)

    Objective: To investigate the value of prophylactic irradiation to the lymphatic drainage area in radical three-dimensional conformal radiotherapy (3DCRT) and to evaluate the efficacy and adverse effects of 3DCRT with different clinical target volumes. Methods: A retrospective analysis was performed on the records of 219 esophageal cancer patients without distant metastasis who received 3DCRT from January 2005 to December 2010. One hundred and five patients received involved-field irradiation (IFI) with a total dose of 54-66 Gy; 114 patients received elective nodal irradiation (ENI) with a total dose of 46-52 Gy; the prescribed dose to the primary lesion was 56-70 Gy. The Kaplan-Meier method was used to calculate local control (LC) and overall survival (OS) rates,and the log-rank test was used for univariate prognostic analysis. Results: The 1-, 3-, and 5-year sample sizes were 219, 172 and 67,respectively. The 1-,3-,and 5-year LC rates for IFI group were 63.0%, 39.1%, and 27.2%, respectively, versus 70.5%, 53.3%, and 51.7% for ENI group (χ2=6.22, P=0.013); the 1-, 3-, and 5-year OS rates for IFI group were 67.6%, 24.9%, and 15.0%, respectively, versus 73.7%, 45.1%, and 26.0% for ENI group (χ2=5.04, P=0.025). The univariate stratified analysis showed that the LC and OS rates were significantly higher in the ENI group than in the IFI group for patients with middle-or lower-thoracic primary lesion or N0 disease (P=0.007, 0.015; P=0.054, 0.013). Conclusions: For esophageal cancer patients with middle-or lower-thoracic primary lesion or without lymph node metastasis, prophylactic irradiation to the lymphatic drainage area can increase LC and OS rates. (authors)

  8. How iliopelvic lymphoscintigraphy can affect the definition of planning target volume in radiation therapy of pelvic and testicular tumors

    International Nuclear Information System (INIS)

    Purpose: External beam radiation therapy (EBRT) of most intrapelvic and testicular tumors has been generally performed with large fields encompassing both the primary disease and lymphatic drainage. This study was carried out to map the pelvic and periaortic lymphatics by means of iliopelvic lymphoscintigraphy (IPL) in preparation for radiotherapy planning. Methods and Materials: Between January 2000 and October 2001, 70 patients scheduled for EBRT (61 operated on, 52 females, 18 males, mean age 61, range, 24-80), affected with uterine (43), rectal (11), testicular (8), anal (4), penile (2), and vulvar (2) cancers were enrolled in the study. IPL was performed by injection of 99mtechnetium-nanocolloids in the bipedal (70 cases) or bipedal plus perianal (20 cases) sites. The sensitivity of IPL in mapping the lymphatic anatomy was evaluated first. Then three radiation oncologists scored the modifications induced by IPL on the planning target volume (PTV) which had been previously delineated only on the basis of bony landmarks. The original fields were classified 'inadequate' if they failed to match the new PTV by more than 1 cm. Results: IPL sensitivity in showing the inguinal, external iliac, common, and periaortic lymphatics was 100%, 90%, 80%, and 70% in anterior-posterior (A-P) projections, and 100%, 80%, 70%, and 60% in lateral projections respectively. For the presacral and hypogastric ones the sensitivity was 40%. When compared with bony landmarks, IPL changed the delineation of PTV in 24 of 70 A-P P-A fields (34%) and 22 of 58 (38%) lateral fields. Furthermore, 8/12 (67%) lymphadenectomies resulted in being incomplete. No IPL-related toxicity was observed. Conclusion: IPL is a safe, inexpensive (cost: 100 Euros), and effective method to map the lymphatic chains. In the A-P scintigrams these structures were detected in 85% (70-100%) of the patients referred for total pelvis irradiation, and this figure could be higher in subjects not operated on. IPL can also

  9. Monte-Carlo model development for evaluation of current clinical target volume definition for heterogeneous and hypoxic glioblastoma

    Science.gov (United States)

    Moghaddasi, L.; Bezak, E.; Harriss-Phillips, W.

    2016-05-01

    Clinical target volume (CTV) determination may be complex and subjective. In this work a microscopic-scale tumour model was developed to evaluate current CTV practices in glioblastoma multiforme (GBM) external radiotherapy. Previously, a Geant4 cell-based dosimetry model was developed to calculate the dose deposited in individual GBM cells. Microscopic extension probability (MEP) models were then developed using Matlab-2012a. The results of the cell-based dosimetry model and MEP models were combined to calculate survival fractions (SF) for CTV margins of 2.0 and 2.5 cm. In the current work, oxygenation and heterogeneous radiosensitivity profiles were incorporated into the GBM model. The genetic heterogeneity was modelled using a range of α/β values (linear-quadratic model parameters) associated with different GBM cell lines. These values were distributed among the cells randomly, taken from a Gaussian-weighted sample of α/β values. Cellular oxygen pressure was distributed randomly taken from a sample weighted to profiles obtained from literature. Three types of GBM models were analysed: homogeneous-normoxic, heterogeneous-normoxic, and heterogeneous-hypoxic. The SF in different regions of the tumour model and the effect of the CTV margin extension from 2.0–2.5 cm on SFs were investigated for three MEP models. The SF within the beam was increased by up to three and two orders of magnitude following incorporation of heterogeneous radiosensitivities and hypoxia, respectively, in the GBM model. However, the total SF was shown to be overdominated by the presence of tumour cells in the penumbra region and to a lesser extent by genetic heterogeneity and hypoxia. CTV extension by 0.5 cm reduced the SF by a maximum of 78.6  ±  3.3%, 78.5  ±  3.3%, and 77.7  ±  3.1% for homogeneous and heterogeneous-normoxic, and heterogeneous hypoxic GBMs, respectively. Monte-Carlo model was developed to quantitatively evaluate SF for genetically

  10. Prospective comparative evaluation of planning target volume margin for brain intensity modulated radiotherapy utilizing hybrid online imaging modalities

    Directory of Open Access Journals (Sweden)

    Sayan Paul

    2015-01-01

    Full Text Available Background: A new advancement in daily monitoring of patient positioning is the use of hybrid technologies where two separate online imaging modalities are integrated to achieve precise treatment delivery. Our center has a set-up that integrates Elekta Linear accelerator device (EPID with BrainLAB ExacTrac imaging for the first time in the world. We calculated planning target volume (PTV margin for brain radiotherapy with thermoplastic mask immobilization with conventional EPID and BrainLAB ExacTrac image guidance system. Materials and Methods: EPID (iViewGT and ExacTrac verification images of 32 patients in total 784 radiotherapy sessions were acquired and analyzed. Systematic (Σ and random errors (σ were calculated in cranio-caudal, lateral and anteroposterior directions. PTV margins calculated using van Herk (2.5 Σ +0.7 σ formula for each imaging system. Result: Of total 784 sessions EPID image were obtained in 723 sessions, ExacTrac obtained in 431 sessions. In cranio-caudal direction, the systematic error, random error, and the calculated PTV margin were 0.09 cm, 0.12 cm, and 0.31 cm, respectively, with EPID image and 0.17 cm, 0.13 cm, and 0.51 cm, respectively, with ExacTrac. The corresponding values in lateral direction were 0.11 cm, 0.15 cm, and 0.40 cm with EPID and 0.16 cm, 0.10 cm, and 0.47 cm, respectively, with ExacTrac image. The same parameters for anteroposterior were 0.10 cm, 0.13 cm, 0.37 cm with EPID and 0.144 cm, 0.10 cm, and 0.43 cm with ExacTrac image. Pearson's correlation coefficient was found to be 0.66, 0.67, 0.62 in these three directions. Conclusion: With dual imaging modalities, our calculated adequate PTV margin for brain radiotherapy cases are 0.51 cm, 0.47 cm, is 0.43 cm in cranio-caudal, right-left, and anteroposterior directions, respectively.

  11. An off-line strategy for constructing a patient-specific planning target volume in adaptive treatment process for prostate cancer

    International Nuclear Information System (INIS)

    Purpose: To improve the efficacy of dose delivery and dose escalation for external beam radiotherapy of prostate cancer, an off-line strategy for constructing a patient-specific planning target volume is developed in the adaptive radiotherapy process using image feedback of target location and patient setup position. Materials and Methods: We hypothesize that a patient-specific confidence-limited planning target volume (cl-PTV), constructed using an initial sequence of daily measurements of internal target motion and patient setup error, exists and ensures that the clinical target volume (CTV) in the prostate cancer patient receives the prescribed dose within a predefined dose tolerance. A patient-specific bounding volume to correct for target location and compensate for target random motion was first constructed using the convex hull of the first k days of CT measurements. The bounding volume and the initial days of CT measurements were minimized based on a predefined dosimetric criterion. The hypothesis was tested using multiple daily CT images by mimicking the actual treatment of both conventional 4-field-box and intensity-modulated radiotherapy (IMRT) on each of 30 patients with prostate cancer. For each patient, a patient-specific setup margin was also applied to the bounding volume to form the final cl-PTV. This margin was determined using the random setup error predicted from the initial days of portal imaging measurements and the residuals after correcting for the systematic setup error. Results: The bounding volume constructed using daily CT measurements in the first week of treatment are adequate for the conventional beam delivery to achieve maximum dose reduction in the CTV of 2% or less of the prescription dose, for at least 80% of patients (p = 0.08), and 4.5% or less for 95% of patients (p 0.1). However, for IMRT delivery, 2 weeks of daily CT measurements are required to achieve a similar level of the dosimetric criterion, otherwise the maximum dose

  12. Evaluation of variability in target volume delineation for newly diagnosed glioblastoma: a multi-institutional study from the Korean Radiation Oncology Group

    International Nuclear Information System (INIS)

    This study aimed for a collaborative evaluation of variability in the target volumes for glioblastoma, determined and contoured by different radiotherapy (RT) facilities in Korea. Fifteen panels of radiation oncologists from independent institutions contoured the gross target volumes (GTVs) and clinical target volumes (CTVs) for 3-dimensional conformal RT or intensity-modulated RT on each simulation CT images, after scrutinizing the enhanced T1-weighted and T2-weighted-fluid-attenuated inversion recovery MR images of 9 different cases of glioblastoma. Degrees of contouring agreement were analyzed by the kappa statistics. Using the algorithm of simultaneous truth and performance level estimation (STAPLE), GTVSTAPLE and CTVSTAPLE contours were derived. Contour agreement was moderate (mean kappa 0.58) among the GTVs and was substantial (mean kappa 0.65) among the CTVs. However, each panels’ GTVs and modification of CTVs regarding anatomical structures varied. Three-fourth of contoured panels’ CTVs encompassed the peritumoral areas of T2-high signal intensity (T2-HSI). Nine of nine GTVSTAPLE encompased the surgical cavity and the T1-enhanced lesions. Eight of nine CTVSTAPLE encompassed the peritumoral T2-HSI area. The median MARGIN90 and the median MARGIN95 were 1.4 cm and 1.5 cm, respectively. Moderate to substantial agreement existed in target volumes for 3-dimensional or intensity-modulated RT determined by radiation oncologists in Korea. According to the estimated consensus contours, the initial CTV encompassed the GTV with margin less than 2.0 cm and the whole peritumoral areas of T2-HSI. The findings of our study propose the need for further studies and modified guidelines. The online version of this article (doi:10.1186/s13014-015-0439-z) contains supplementary material, which is available to authorized users

  13. Efficacy of the smaller target volume for stage III non-small cell lung cancer treated with intensity-modulated radiotherapy

    OpenAIRE

    LIANG, XIANGCUN; Yu, Huiming; Yu, Rong; Xu, Gang; Guangying ZHU

    2015-01-01

    The present study reports the local recurrence, distant metastasis, progression-free survival, overall survival and radiation toxicity between two arms of stage III non-small cell lung cancer (NSCLC) treated with intensity-modulated radiotherapy (IMRT); one arm with clinical target volume (CTV) and the other without CTV. The two arms of local recurrence, distant metastasis, progression-free survival, overall survival, grade 3–4 radiation esophagitis and hematological toxicity had no statistic...

  14. Delineation of target volumes and organs at risk in adjuvant radiotherapy of early breast cancer: National guidelines and contouring atlas by the Danish Breast Cancer Cooperative Group

    International Nuclear Information System (INIS)

    During the past decade planning of adjuvant radiotherapy (RT) of early breast cancer has changed from two-dimensional (2D) to 3D conformal techniques. In the planning computerised tomography (CT) scan both the targets for RT and the organs at risk (OARs) are visualised, enabling an increased focus on target dose coverage and homogeneity with only minimal dose to the OARs. To ensure uniform RT in the national prospective trials of the Danish Breast Cancer Cooperative Group (DBCG), a national consensus for the delineation of clinical target volumes (CTVs) and OARs was required. Material and methods. A CT scan of a breast cancer patient after surgical breast conservation and axillary lymph node (LN) dissection was used for delineation. During multiple dummy-runs seven experienced radiation oncologists contoured all CTVs and OARs of interest in adjuvant breast RT. Two meetings were held in the DBCG Radiotherapy Committee to discuss the contouring and to approve a fi nal consensus. The Dice similarity coefficient (DSC) was used to evaluate the delineation agreement before and after the consensus. Results. The consensus delineations of CTVs and OARs are available online and a table is presented with a contouring description of the individual volumes. The consensus provides recommendations for target delineation in a standard patient both in case of breast conservation or mastectomy. Before the consensus, the average value of the DSC was modest for most volumes, but high for the breast CTV and the heart. After the consensus, the DSC increased for all volumes. Conclusion. The DBCG has provided the fi rst national guidelines and a contouring atlas of CTVs and OARs definition for RT of early breast cancer. The DSC is a useful tool in quantifying the effect of the introduction of guidelines indicating improved inter-delineator agreement. This consensus will be used by the DBCG in our prospective trials

  15. High-resolution x-ray imaging of Kα volume radiation induced by high-intensity laser pulse interaction with a copper target

    Czech Academy of Sciences Publication Activity Database

    Galtier, E.; Moinard, A.; Khattak, F.Y.; Renner, Oldřich; Robert, T.; Santos, J.J.; Beaucourt, C.; Angelo, P.; Tikhonchuk, V.; Rosmej, F.B.

    2012-01-01

    Roč. 45, č. 20 (2012), s. 1-6. ISSN 0953-4075 R&D Projects: GA ČR GAP205/10/0814 Institutional research plan: CEZ:AV0Z10100523 Keywords : laser -matter interaction * x-ray spectroscopy * particle generation * x-ray imaging * Kα volume radiation * Cu targets Subject RIV: BH - Optics, Masers, Laser s Impact factor: 2.031, year: 2012

  16. TU-A-12A-06: Intra-Observer Variability in Delineation of Target Volumes in Breast Radiotherapy and Its Effect On Accuracy of Deformation Measurements

    International Nuclear Information System (INIS)

    Purpose: In breast radiotherapy, the target volume may change during treatment and need adaptation of the treatment plan. This is possible for both tumour bed (TB) and whole breast (WB) target volumes. Delineation of the target (to detect changes) is also subject to uncertainty due to intra- and inter-observer variability. This work measured the uncertainty, due to intraobserver variability, in the quantification of tissue deformation. Methods: Datasets consisting of paired prone and supine CT scans of three patients were used. Significant deformation in target volumes is expected between prone and supine patient positions. The selected cases had 1) no seroma, 2) some seroma, and 3) large seroma. The TB and WB were outlined on each dataset three times by one clinician. Delineation variability was defined as the standard deviations of the distances between observer outlines. For each target volume and each case, tissue deformation between prone and supine delineations was quantified using the Dice similarity coefficient (DSC) and the average surface distance (ASD). The uncertainty in the tissue deformation (due to delineation variability) was quantified by measuring the ranges of DSC and ASD using all combinations of pairs of outlines (9 pairs). Results: For the TB, the range of delineation variability was 0.44-1.16 mm. The deformation, DSC and ASD, (and uncertainty in measurement) of the TB between prone and supine position of the cases were: 1) 0.21 (0.17-0.28) and 12.4 mm (11.8-13 mm); 2) 0.54 (0.51-0.57) and 3.3 mm (3.1-3.5 mm); 3) 0.62 (0.61-0.64) and 4.9 mm (4.6-5.2 mm). WB deformation measurements were subject to less uncertainty due to delineation variability than TB deformation measurements. Conclusion: For the first time, the uncertainty, due to observer variability, in the measurement of the deformation of breast target volumes was investigated. Deformations in these ranges would be difficult to detect. This work was supported in part by Cancer Research

  17. Determining optimal clinical target volume margins in head-and-neck cancer based on microscopic extracapsular extension of metastatic neck nodes

    International Nuclear Information System (INIS)

    Purpose: To determine the optimal clinical target volume margins around the gross nodal tumor volume in head-and-neck cancer by assessing microscopic tumor extension beyond cervical lymph node capsules. Methods and Materials: Histologic sections of 96 dissected cervical lymph nodes with extracapsular extension (ECE) from 48 patients with head-and-neck squamous cell carcinoma were examined. The maximum linear distance from the external capsule border to the farthest extent of the tumor or tumoral reaction was measured. The trends of ECE as a function of the distance from the capsule and lymph node size were analyzed. Results: The median diameter of all lymph nodes was 11.0 mm (range: 3.0-30.0 mm). The mean and median ECE extent was 2.2 mm and 1.6 mm, respectively (range: 0.4-9.0 mm). The ECE was <5 mm from the capsule in 96% of the nodes. As the distance from the capsule increased, the probability of tumor extension declined. No significant difference between the extent of ECE and lymph node size was observed. Conclusion: For N1 nodes that are at high risk for ECE but not grossly infiltrating musculature, 1 cm clinical target volume margins around the nodal gross tumor volume are recommended to cover microscopic nodal extension in head-and-neck cancer

  18. The impact of time between staging PET/CT and definitive chemo-radiation on target volumes and survival in patients with non-small cell lung cancer

    International Nuclear Information System (INIS)

    Background and purpose: To investigate the impact of treatment delays on radiation therapy (RT) target volumes and overall survival (OS) in patients with non-small cell lung cancer (NSCLC) who underwent two baseline FDG PET/CT scans. Material and methods: Patients underwent a staging (PET1) and RT planning (PET2) FDG PET/CT scan. At PET1 all patients were eligible for radical chemo-RT. OS and progression-free survival (PFS) were compared for patients remaining eligible for radical RT and those treated palliatively because PET2 showed progression. RT target volumes were contoured using PET1 and PET2. Normal tissue doses were compared for patients remaining eligible for radical RT. Results: Eighty-two patients underwent PET2 scans between October 2004 and February 2007. Of these, 21 had a prior PET1 scan, median 23 days apart (range 8–176 days). Six patients (29%) were unsuitable for radical RT after PET2; five received palliative treatment and one received no treatment. Patients treated palliatively had significantly worse OS and PFS than patients treated radically p < 0.001. Mean RT tumour volume increased from 105cc to 198cc (p < 0.005) between scans. Conclusions: Disease progression while awaiting initiation of curative RT in NSCLC is associated with larger treatment volumes and worse survival

  19. Comparison of planning target volumes based on three-dimensional CT and four-dimensional CT simulation images of non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Objective: To compare the positional and volumetric differences of planning target volumes (PTVs) based on axial three-dimensional CT (3D-CT) and four-dimensional CT (4D-CT) for the primary tumor of non-small cell lung cancer (NSCLC). Methods: Sixteen NSCLC patients with lesions located in the upper lobe and 12 patients with lesions in middle and lower lobes, totally 28 patients, initially underwent three-dimensional CT scans followed by 4D-CT scans of the thorax under normal free breathing. PTVvector was defined on gross tumor volume (GTV) contoured on 3D-CT and its motion vector. The clinical target volumes (CTVs) were created by adding 7 mm to GTVs, then, internal target volume (ITVs) were produced by enlarging CTVs isotropically based on the individually measured amount of motion in the 4D-CT, lastly, PTVs were created by adding 3 mm setup margin to ITVs. PTV4D was defined on the fusion of CTVs on all phases of the 4D data. The CTV wag generated by adding 7 mm to the GTV on each phase, then, PTVs were produced by fusing CTVs on 10 phases and adding 3 mm setup margin. The position of the target center, the volume of target and the degree of inclusion (DI) were compared reciprocally between the PTVvector and the PTV4D The difference of the position, volume and degree of inclusion of the targets between PTVvector and PTV4D were compared, and the relevance between the relative characters of the targets and the three-dimensional vector was analyzed based on the groups of the patients. Results: The median of the 3 D motion vector for the lesions in the upper lobe was 2.8 mm, significantly lower than that for the lesions in the middle and lower lobe (7.0 mm, z=-3.485, P<0.05). In the upper lobe group there was only significant spatial difference between the PTVvector and PTV4D targets in the center coordinate at the x axe (z=-2.010, P<0.05), while in the middle and lower lobes there was only significant spatial difference between the PTVvector and PTV4D targets in the

  20. The potential advantages of 18FDG PET/CT-based target volume delineation in radiotherapy planning of head and neck cancer

    International Nuclear Information System (INIS)

    Purpose: This study investigated two fixed threshold methods to delineate the target volume using 18FDG PET/CT before and during a course of radical radiotherapy in locally advanced squamous cell carcinoma of the head and neck. Materials and methods: Patients were enrolled into the study between March 2006 and May 2008. 18FDG PET/CT scans were carried out 72 h prior to the start of radiotherapy and then at 10, 44 and 66 Gy. Functional volumes were delineated according to the SUV Cut Off (SUVCO) (2.5, 3.0, 3.5, and 4.0 bwg/ml) and percentage of the SUVmax (30%, 35%, 40%, 45%, and 50%) thresholds. The background 18FDG uptake and the SUVmax within the volumes were also assessed. Results: Primary and lymph node volumes for the eight patients significantly reduced with each increase in the delineation threshold (for example 2.5-3.0 bwg/ml SUVCO) compared to the baseline threshold at each imaging point. There was a significant reduction in the volume (p ≤ 0.0001-0.01) after 36 Gy compared to the 0 Gy by the SUVCO method. There was a negative correlation between the SUVmax within the primary and lymph node volumes and delivered radiation dose (p ≤ 0.0001-0.011) but no difference in the SUV within the background reference region. The volumes delineated by the PTSUVmax method increased with the increase in the delivered radiation dose after 36 Gy because the SUVmax within the region of interest used to define the edge of the volume was equal or less than the background 18FDG uptake and the software was unable to effectively differentiate between tumour and background uptake. Conclusions: The changes in the target volumes delineated by the SUVCO method were less susceptible to background 18FDG uptake compared to those delineated by the PTSUVmax and may be more helpful in radiotherapy planning. The best method and threshold have still to be determined within institutions, both nationally and internationally.

  1. The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

    International Nuclear Information System (INIS)

    Purpose: Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment. Methods: A Perspex thorax phantom was used to simulate a patient. Three wooden “lung” inserts with embedded Perspex “lesions” were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours. Results: When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to

  2. Radiotherapy of large target volumes in Hodgkin's lymphoma: normal tissue sparing capability of forward IMRT versus conventional techniques

    International Nuclear Information System (INIS)

    This paper analyses normal tissue sparing capability of radiation treatment techniques in Hodgkin's lymphoma with large treatment volume. 10 patients with supradiaphragmatic Hodgkin's lymphoma and planning target volume (PTV) larger than 900 cm3 were evaluated. Two plans were simulated for each patient using 6 MV X-rays: a conventional multi-leaf (MLC) parallel-opposed (AP-PA) plan, and the same plan with additional MLC shaped segments (forward planned intensity modulated radiation therapy, FPIMRT). In order to compare plans, dose-volume histograms (DVHs) of PTV, lungs, heart, spinal cord, breast, and thyroid were analyzed. The Inhomogeneity Coefficient (IC), the PTV receiving 95% of the prescription dose (V95), the normal tissue complication probability (NTCP) and dose-volume parameters for the OARs were determined. the PTV coverage was improved (mean V95AP-PA = 95.9 and ICAP-PA = 0.4 vs. V95FPIMRT = 96.8 and ICFPIMRT = 0.31, p ≤ 0.05) by the FPIMRT technique compared to the conventional one. At the same time, NTCPs of lung, spinal cord and thyroid, and the volume of lung and thyroid receiving ≥ 30 Gy resulted significantly reduced when using the FPIMRT technique. The FPIMRT technique can represent a very useful and, at the same time, simple method for improving PTV conformity while saving critical organs when large fields are needed as in Hodgkin's lymphoma

  3. The influence of target and patient characteristics on the volume obtained from cone beam CT in lung stereotactic body radiation therapy

    International Nuclear Information System (INIS)

    Purpose: To investigate the influence of tumor and patient characteristics on the target volume obtained from cone beam CT (CBCT) in lung stereotactic body radiation therapy (SBRT). Materials and methods: For a given cohort of 71 patients, the internal target volume (ITV) in CBCT obtained from four different datasets was compared with a reference ITV drawn on a four-dimensional CT (4DCT). The significance of the tumor size, location, relative target motion (RM) and patient’s body mass index (BMI) and gender on the adequacy of ITV obtained from CBCT was determined. Results: The median ITV-CBCT was found to be smaller than the ITV-4DCT by 11.8% (range: −49.8 to +24.3%, P < 0.001). Small tumors located in the lower lung were found to have a larger RM than large tumors in the upper lung. Tumors located near the central lung had high CT background which reduced the target contrast near the edges. Tumor location close to center vs. periphery was the only significant factor (P = 0.046) causing underestimation of ITV in CBCT, rather than RM (P = 0.323) and other factors. Conclusions: The current clinical study has identified that the location of tumor is a major source of discrepancy between ITV-CBCT and ITV-4DCT for lung SBRT

  4. RTOG Sarcoma Radiation Oncologists Reach Consensus on Gross Tumor Volume (GTV) and Clinical Target Volume (CTV) on Computed Tomographic Images for Preoperative Radiotherapy of Primary Soft Tissue Sarcoma of Extremity in RTOG Studies

    Science.gov (United States)

    Wang, Dian; Bosch, Walter; Roberge, David; Finkelstein, Steven E.; Petersen, Ivy; Haddock, Michael; Chen, Yen-Lin E.; Saito, Naoyuki G.; Kirsch, David G.; Hitchcock, Ying J.; Wolfson, Aaron H.; DeLaney, Thomas F.

    2011-01-01

    Objective To develop an Radiation Therapy Oncology Group (RTOG) atlas delineating gross tumor volume (GTV), and clinical target volume (CTV) to be used for preoperative radiotherapy of primary extremity soft tissue sarcoma (STS). Methods A consensus meeting was held during the RTOG meeting in January 2010 to reach agreement about GTV and CTV delineation on CT images for preoperative radiotherapy of high-grade large extremity STS. Data were presented to address the local extension of STS. Extensive discussion ensued to develop optimal criteria for GTV and CTV delineation on CT images. Results A consensus was reached on appropriate CT-based GTV and CTV. GTV is gross tumor defined by T1 contrast-enhanced MRI images. Fusion of MRI and CT is recommended to delineate the GTV. CTV for high-grade large STS typically includes GTV plus 3 cm margins in the longitudinal directions. If this causes the field to extend beyond the compartment, the field can be shortened to include the end of a compartment. The radial margin from the lesion should be 1.5 cm including any portion of the tumor not confined by an intact fascial barrier, bone or skin surface. Conclusion The consensus on GTV and CTV for preoperative radiotherapy of high-grade large extremity STS is available as web-based images as well as descriptive format through the RTOG. This is expected to improve target volume consistency and allow for rigorous evaluation of the benefits and risks of such treatment. PMID:21676552

  5. Impact of 4D-18FDG-PET/CT imaging on target volume delineation in SBRT patients with central versus peripheral lung tumors. Multi-reader comparative study

    International Nuclear Information System (INIS)

    Purpose: Evaluation of the effect of co-registered 4D-18FDG-PET/CT for SBRT target delineation in patients with central versus peripheral lung tumors. Methods: Analysis of internal target volume (ITV) delineation of central and peripheral lung lesions in 21 SBRT-patients. Manual delineation was performed by 4 observers in 2 contouring phases: on respiratory gated 4DCT with diagnostic 3DPET available aside (CT-ITV) and on co-registered 4DPET/CT (PET/CT-ITV). Comparative analysis of volumes and inter-reader agreement. Results: 11 cases of peripheral and 10 central lesions were evaluated. In peripheral lesions, average CT-ITV was 6.2 cm3 and PET/CT-ITV 8.6 cm3, resembling a mean change in hypothetical radius of 2 mm. For both CT-ITVs and PET/CT-ITVs inter reader agreement was good and unchanged (0.733 and 0.716; p = 0.58). All PET/CT-ITVs stayed within the PTVs derived from CT-ITVs. In central lesions, average CT-ITVs were 42.1 cm3, PET/CT-ITVs 44.2 cm3, without significant overall volume changes. Inter-reader agreement improved significantly (0.665 and 0.750; p < 0.05). 2/10 PET/CT-ITVs exceeded the PTVs derived from CT-ITVs by >1 ml in average for all observers. Conclusion: The addition of co-registered 4DPET data to 4DCT based target volume delineation for SBRT of centrally located lung tumors increases the inter-observer agreement and may help to avoid geographic misses

  6. A predictive model to guide management of the overlap region between target volume and organs at risk in prostate cancer volumetric modulated arc therapy

    International Nuclear Information System (INIS)

    The goal of this study is to determine whether the magnitude of overlap between planning target volume (PTV) and rectum (Rectumoverlap) or PTV and bladder (Bladderoverlap) in prostate cancer volumetric-modulated arc therapy (VMAT) is predictive of the dose-volume relationships achieved after optimization, and to identify predictive equations and cutoff values using these overlap volumes beyond which the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) dose-volume constraints are unlikely to be met. Fifty-seven patients with prostate cancer underwent VMAT planning using identical optimization conditions and normalization. The PTV (for the 50.4 Gy primary plan and 30.6 Gy boost plan) included 5 to 10 mm margins around the prostate and seminal vesicles. Pearson correlations, linear regression analyses, and receiver operating characteristic (ROC) curves were used to correlate the percentage overlap with dose-volume parameters. The percentage Rectumoverlap and Bladderoverlap correlated with sparing of that organ but minimally impacted other dose-volume parameters, predicted the primary plan rectum V45 and bladder V50 with R2 = 0.78 and R2 = 0.83, respectively, and predicted the boost plan rectum V30 and bladder V30 with R2 = 0.53 and R2 = 0.81, respectively. The optimal cutoff value of boost Rectumoverlap to predict rectum V75 >15% was 3.5% (sensitivity 100%, specificity 94%, p overlap to predict bladder V80 >10% was 5.0% (sensitivity 83%, specificity 100%, p < 0.01). The degree of overlap between PTV and bladder or rectum can be used to accurately guide physicians on the use of interventions to limit the extent of the overlap region prior to optimization.

  7. A predictive model to guide management of the overlap region between target volume and organs at risk in prostate cancer volumetric modulated arc therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mattes, Malcolm D.; Lee, Jennifer C.; Einaiem, Sara; Guirguis, Adel; Ikoro, N. C.; Ashamalla Hani [Dept. of Radiation Oncology, New York Methodist Hospital, Brooklyn (United States)

    2013-12-15

    The goal of this study is to determine whether the magnitude of overlap between planning target volume (PTV) and rectum (Rectum{sub overlap}) or PTV and bladder (Bladder{sub overlap}) in prostate cancer volumetric-modulated arc therapy (VMAT) is predictive of the dose-volume relationships achieved after optimization, and to identify predictive equations and cutoff values using these overlap volumes beyond which the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) dose-volume constraints are unlikely to be met. Fifty-seven patients with prostate cancer underwent VMAT planning using identical optimization conditions and normalization. The PTV (for the 50.4 Gy primary plan and 30.6 Gy boost plan) included 5 to 10 mm margins around the prostate and seminal vesicles. Pearson correlations, linear regression analyses, and receiver operating characteristic (ROC) curves were used to correlate the percentage overlap with dose-volume parameters. The percentage Rectum{sub overlap} and Bladder{sub overlap} correlated with sparing of that organ but minimally impacted other dose-volume parameters, predicted the primary plan rectum V{sub 45} and bladder V{sub 50} with R{sup 2} = 0.78 and R{sup 2} = 0.83, respectively, and predicted the boost plan rectum V{sub 30} and bladder V{sub 30} with R{sup 2} = 0.53 and R{sup 2} = 0.81, respectively. The optimal cutoff value of boost Rectumoverlap to predict rectum V75 >15% was 3.5% (sensitivity 100%, specificity 94%, p < 0.01), and the optimal cutoff value of boost Bladder{sub overlap} to predict bladder V{sub 80} >10% was 5.0% (sensitivity 83%, specificity 100%, p < 0.01). The degree of overlap between PTV and bladder or rectum can be used to accurately guide physicians on the use of interventions to limit the extent of the overlap region prior to optimization.

  8. Use of combined maximum and minimum intensity projections to determine internal target volume in 4-dimensional CT scans for hepatic malignancies

    Directory of Open Access Journals (Sweden)

    Liu Jin

    2012-01-01

    Full Text Available Abstract Background To evaluate the accuracy of the combined maximum and minimum intensity projection-based internal target volume (ITV delineation in 4-dimensional (4D CT scans for liver malignancies. Methods 4D CT with synchronized IV contrast data were acquired from 15 liver cancer patients (4 hepatocellular carcinomas; 11 hepatic metastases. We used five approaches to determine ITVs: (1. ITVAllPhases: contouring gross tumor volume (GTV on each of 10 respiratory phases of 4D CT data set and combining these GTVs; (2. ITV2Phase: contouring GTV on CT of the peak inhale phase (0% phase and the peak exhale phase (50% and then combining the two; (3. ITVMIP: contouring GTV on MIP with modifications based on physician's visual verification of contours in each respiratory phase; (4. ITVMinIP: contouring GTV on MinIP with modification by physician; (5. ITV2M: combining ITVMIP and ITVMinIP. ITVAllPhases was taken as the reference ITV, and the metrics used for comparison were: matching index (MI, under- and over-estimated volume (Vunder and Vover. Results 4D CT images were successfully acquired from 15 patients and tumor margins were clearly discernable in all patients. There were 9 cases of low density and 6, mixed on CT images. After comparisons of metrics, the tool of ITV2M was the most appropriate to contour ITV for liver malignancies with the highest MI of 0.93 ± 0.04 and the lowest proportion of Vunder (0.07 ± 0.04. Moreover, tumor volume, target motion three-dimensionally and ratio of tumor vertical diameter over tumor motion magnitude in cranio-caudal direction did not significantly influence the values of MI and proportion of Vunder. Conclusion The tool of ITV2M is recommended as a reliable method for generating ITVs from 4D CT data sets in liver cancer.

  9. Antagomirs targeting microRNA-134 increase hippocampal pyramidal neuron spine volume in vivo and protect against pilocarpine-induced status epilepticus.

    Science.gov (United States)

    Jimenez-Mateos, Eva M; Engel, Tobias; Merino-Serrais, Paula; Fernaud-Espinosa, Isabel; Rodriguez-Alvarez, Natalia; Reynolds, James; Reschke, Cristina R; Conroy, Ronan M; McKiernan, Ross C; deFelipe, Javier; Henshall, David C

    2015-07-01

    Emerging data support roles for microRNA (miRNA) in the pathogenesis of various neurologic disorders including epilepsy. MicroRNA-134 (miR-134) is enriched in dendrites of hippocampal neurons, where it negatively regulates spine volume. Recent work identified upregulation of miR-134 in experimental and human epilepsy. Targeting miR-134 in vivo using antagomirs had potent anticonvulsant effects against kainic acid-induced seizures and was associated with a reduction in dendritic spine number. In the present study, we measured dendritic spine volume in mice injected with miR-134-targeting antagomirs and tested effects of the antagomirs on status epilepticus triggered by the cholinergic agonist pilocarpine. Morphometric analysis of over 6,400 dendritic spines in Lucifer yellow-injected CA3 pyramidal neurons revealed increased spine volume in mice given antagomirs compared to controls that received a scrambled sequence. Treatment of mice with miR-134 antagomirs did not alter performance in a behavioral test (novel object location). Status epilepticus induced by pilocarpine was associated with upregulation of miR-134 within the hippocampus of mice. Pretreatment of mice with miR-134 antagomirs reduced the proportion of animals that developed status epilepticus following pilocarpine and increased animal survival. In antagomir-treated mice that did develop status epilepticus, seizure onset was delayed and total seizure power was reduced. These studies provide in vivo evidence that miR-134 regulates spine volume in the hippocampus and validation of the seizure-suppressive effects of miR-134 antagomirs in a model with a different triggering mechanism, indicating broad conservation of anticonvulsant effects. PMID:24874920

  10. Use of combined maximum and minimum intensity projections to determine internal target volume in 4-dimensional CT scans for hepatic malignancies

    International Nuclear Information System (INIS)

    To evaluate the accuracy of the combined maximum and minimum intensity projection-based internal target volume (ITV) delineation in 4-dimensional (4D) CT scans for liver malignancies. 4D CT with synchronized IV contrast data were acquired from 15 liver cancer patients (4 hepatocellular carcinomas; 11 hepatic metastases). We used five approaches to determine ITVs: (1). ITVAllPhases: contouring gross tumor volume (GTV) on each of 10 respiratory phases of 4D CT data set and combining these GTVs; (2). ITV2Phase: contouring GTV on CT of the peak inhale phase (0% phase) and the peak exhale phase (50%) and then combining the two; (3). ITVMIP: contouring GTV on MIP with modifications based on physician's visual verification of contours in each respiratory phase; (4). ITVMinIP: contouring GTV on MinIP with modification by physician; (5). ITV2M: combining ITVMIP and ITVMinIP. ITVAllPhases was taken as the reference ITV, and the metrics used for comparison were: matching index (MI), under- and over-estimated volume (Vunder and Vover). 4D CT images were successfully acquired from 15 patients and tumor margins were clearly discernable in all patients. There were 9 cases of low density and 6, mixed on CT images. After comparisons of metrics, the tool of ITV2M was the most appropriate to contour ITV for liver malignancies with the highest MI of 0.93 ± 0.04 and the lowest proportion of Vunder (0.07 ± 0.04). Moreover, tumor volume, target motion three-dimensionally and ratio of tumor vertical diameter over tumor motion magnitude in cranio-caudal direction did not significantly influence the values of MI and proportion of Vunder. The tool of ITV2M is recommended as a reliable method for generating ITVs from 4D CT data sets in liver cancer

  11. Variations in Target Volume Definition for Postoperative Radiotherapy in Stage III Non-Small-Cell Lung Cancer: Analysis of an International Contouring Study

    International Nuclear Information System (INIS)

    Purpose: Postoperative radiotherapy (PORT) in patients with completely resected non-small-cell lung cancer with mediastinal involvement is controversial because of the failure of earlier trials to demonstrate a survival benefit. Improved techniques may reduce toxicity, but the treatment fields used in routine practice have not been well studied. We studied routine target volumes used by international experts and evaluated the impact of a contouring protocol developed for a new prospective study, the Lung Adjuvant Radiotherapy Trial (Lung ART). Methods and Materials: Seventeen thoracic radiation oncologists were invited to contour their routine clinical target volumes (CTV) for 2 representative patients using a validated CD-ROM-based contouring program. Subsequently, the Lung ART study protocol was provided, and both cases were contoured again. Variations in target volumes and their dosimetric impact were analyzed. Results: Routine CTVs were received for each case from 10 clinicians, whereas six provided both routine and protocol CTVs for each case. Routine CTVs varied up to threefold between clinicians, but use of the Lung ART protocol significantly decreased variations. Routine CTVs in a postlobectomy patient resulted in V20 values ranging from 12.7% to 54.0%, and Lung ART protocol CTVs resulted in values of 20.6% to 29.2%. Similar results were seen for other toxicity parameters and in the postpneumectomy patient. With the exception of upper paratracheal nodes, protocol contouring improved coverage of the required nodal stations. Conclusion: Even among experts, significant interclinician variations are observed in PORT fields. Inasmuch as contouring variations can confound the interpretation of PORT results, mandatory quality assurance procedures have been incorporated into the current Lung ART study.

  12. Patterns of failure and comparison of different target volume delineations in patients with glioblastoma treated with conformal radiotherapy plus concomitant and adjuvant temozolomide

    International Nuclear Information System (INIS)

    Purpose: To analyze the recurrence patterns in patients with newly diagnosed glioblastoma (GBM) treated with conformal radiotherapy (RT) plus concomitant and adjuvant temozolomide (TMZ), and to compare the patterns of failure according to different target volume delineations. Methods and materials: One hundred and five patients with GBM which recurred after three-dimensional (3D) conformal RT plus TMZ were evaluated. The clinical target volume (CTV) used for our treatment planning (S'Andrea plans) consisted of residual tumor and resection cavity plus 2-cm margins according to recent randomized trials of the European Organisation for Research and Treatment of Cancer (EORTC). MRI scans showing tumor recurrences were fused with the planning computed tomography (CT), and the patterns of failure were analyzed dosimetrically using dose-volume histograms. For each patient a theoretical plan based on the addition of postoperative edema plus 2-cm margins according to current guidelines of Radiation Therapy Oncology Group (RTOG) was created and patterns of failure were evaluated. Results: The median overall survival and progression-free survival were 14.2 months and 7.5 months, respectively. Recurrences were central in 79 patients, in-field in 6 patients, marginal in 6 patients, and distant in 14 patients. Analysis of O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation status showed different recurrence patterns of GBMs in patients with MGMT methylated compared with patients with MGMT unmethylated status. Recurrences occurred central/in-field and outside in 64% and 31% of methylated patients, and in 91% and 5.4% of unmethylated patients, respectively (P = 0.01). Patterns of failure were similar between the different treatment plans, however the median volume percent of brain irradiated to high doses was significantly smaller for our plans than for RTOG plans (P = 0.0001). Conclusion: Most of patients treated with RT plus concomitant and adjuvant RT have

  13. Intensity modulated radiation therapy (IMRT: differences in target volumes and improvement in clinically relevant doses to small bowel in rectal carcinoma

    Directory of Open Access Journals (Sweden)

    Delclos Marc E

    2011-06-01

    covered by classic bony landmark-derived fields, without incurring penalty with respect to adjacent organs-at-risk. Conclusions For rectal carcinoma, IMRT, compared to 3DCRT, yielded plans superior with respect to target coverage, homogeneity, and conformality, while lowering dose to adjacent organs-at-risk. This is achieved despite treating larger volumes, raising the possibility of a clinically-relevant improvement in the therapeutic ratio through the use of IMRT with a belly-board apparatus.

  14. High-resolution x-ray imaging of Kα volume radiation induced by high-intensity laser pulse interaction with a copper target

    Science.gov (United States)

    Galtier, E.; Moinard, A.; Khattak, F. Y.; Renner, O.; Robert, T.; Santos, J. J.; Beaucourt, C.; Angelo, P.; Tikhonchuk, V.; Rosmej, F. B.

    2012-10-01

    In a proof of principle experiment using the LULI 100-TW laser facility ELFIE, we have demonstrated high spectral and spatial resolution of Kα volume radiation induced by energetic electrons generated by irradiating solid Cu targets with visible (0.53 µm) 350 fs laser pulses. Employing an x-ray spectrometer equipped with the spherically bent crystal of quartz (502) and with an image plate, single shot Cu-Kα radiation was recorded in first-order reflection allowing for a geometrical mapping of the emission induced by hot electrons with a spatial resolution down to 30 µm. The simultaneously achieved high spectral resolution permitted the identification of asymmetries in the Kα1-group emission profile. Data from the shot in which a part of the laser beam was incident at grazing angle to the target surface show a signature of enhanced lateral transport of energetic electrons.

  15. RTOG Sarcoma Radiation Oncologists Reach Consensus on Gross Tumor Volume and Clinical Target Volume on Computed Tomographic Images for Preoperative Radiotherapy of Primary Soft Tissue Sarcoma of Extremity in Radiation Therapy Oncology Group Studies

    Energy Technology Data Exchange (ETDEWEB)

    Wang Dian, E-mail: dwang@mcw.edu [Medical College of Wisconsin, Milwaukee, WI (United States); Bosch, Walter [Washington University, St. Louis, MO (United States); Roberge, David [McGill University, Montreal, Quebec (Canada); Finkelstein, Steven E. [Moffitt Cancer Center, Tampa, FL (United States); Petersen, Ivy; Haddock, Michael [Mayo Clinic, Rochester, MN (United States); Chen, Yen-Lin E.; Saito, Naoyuki G. [Roswell Park Cancer Institute, Buffalo, NY (United States); Kirsch, David G. [Duke University, Durham, NC (United States); Hitchcock, Ying J. [University of Utah, Salt Lake City, UT (United States); Wolfson, Aaron H. [University of Miami Miller School of Medicine, Miami, FL (United States); DeLaney, Thomas F. [Massachusetts General Hospital, Boston, MA (United States)

    2011-11-15

    Objective: To develop a Radiation Therapy Oncology Group (RTOG) atlas delineating gross tumor volume (GTV) and clinical target volume (CTV) to be used for preoperative radiotherapy of primary extremity soft tissue sarcoma (STS). Methods and Materials: A consensus meeting was held during the RTOG meeting in January 2010 to reach agreement about GTV and CTV delineation on computed tomography (CT) images for preoperative radiotherapy of high-grade large extremity STS. Data were presented to address the local extension of STS. Extensive discussion ensued to develop optimal criteria for GTV and CTV delineation on CT images. Results: A consensus was reached on appropriate CT-based GTV and CTV. The GTV is gross tumor defined by T1 contrast-enhanced magnetic resonance images. Fusion of magnetic resonance and images is recommended to delineate the GTV. The CTV for high-grade large STS typically includes the GTV plus 3-cm margins in the longitudinal directions. If this causes the field to extend beyond the compartment, the field can be shortened to include the end of a compartment. The radial margin from the lesion should be 1.5 cm, including any portion of the tumor not confined by an intact fascial barrier, bone, or skin surface. Conclusion: The consensus on GTV and CTV for preoperative radiotherapy of high-grade large extremity STS is available as web-based images and in a descriptive format through the RTOG. This is expected to improve target volume consistency and allow for rigorous evaluation of the benefits and risks of such treatment.

  16. Variation in the Gross Tumor Volume and Clinical Target Volume for Preoperative Radiotherapy of Primary Large High-Grade Soft Tissue Sarcoma of the Extremity Among RTOG Sarcoma Radiation Oncologists

    Energy Technology Data Exchange (ETDEWEB)

    Wang Dian, E-mail: dwang@mcw.edu [Medical College of Wisconsin, Milwaukee, WI (United States); Bosch, Walter [Washington University, St. Louis, MO (United States); Kirsch, David G. [Duke University, Durham, NC (United States); Al Lozi, Rawan; El Naqa, Issam [Washington University, St. Louis, MO (United States); Roberge, David [McGill University Health Centre, Montreal (Canada); Finkelstein, Steven E. [Moffitt Cancer Center, Tampa, FL (United States); Petersen, Ivy; Haddock, Michael [Mayo Clinic, Rochester, MN (United States); Chen, Yen-Lin E. [Massachusetts General Hospital, Boston, MA (United States); Saito, Naoyuki G. [Roswell Park Cancer Institute, Buffalo, NY (United States); Hitchcock, Ying J. [University of Utah, Salt Lake City, UT (United States); Wolfson, Aaron H. [University of Miami Miller School of Medicine, Miami, FL (United States); DeLaney, Thomas F. [Massachusetts General Hospital, Boston, MA (United States)

    2011-12-01

    Purpose: To evaluate variability in the definition of preoperative radiotherapy gross tumor volume (GTV) and clinical target volume (CTV) delineated by sarcoma radiation oncologists. Methods and Materials: Extremity sarcoma planning CT images along with the corresponding diagnostic MRI from two patients were distributed to 10 Radiation Therapy Oncology Group sarcoma radiation oncologists with instructions to define GTV and CTV using standardized guidelines. The CT data with contours were then returned for central analysis. Contours representing statistically corrected 95% (V95) and 100% (V100) agreement were computed for each structure. Results: For the GTV, the minimum, maximum, mean (SD) volumes (mL) were 674, 798, 752 {+-} 35 for the lower extremity case and 383, 543, 447 {+-} 46 for the upper extremity case. The volume (cc) of the union, V95 and V100 were 882, 761, and 752 for the lower, and 587, 461, and 455 for the upper extremity, respectively. The overall GTV agreement was judged to be almost perfect in both lower and upper extremity cases (kappa = 0.9 [p < 0.0001] and kappa = 0.86 [p < 0.0001]). For the CTV, the minimum, maximum, mean (SD) volumes (mL) were 1145, 1911, 1605 {+-} 211 for the lower extremity case and 637, 1246, 1006 {+-} 180 for the upper extremity case. The volume (cc) of the union, V95, and V100 were 2094, 1609, and 1593 for the lower, and 1533, 1020, and 965 for the upper extremity cases, respectively. The overall CTV agreement was judged to be almost perfect in the lower extremity case (kappa = 0.85 [p < 0.0001]) but only substantial in the upper extremity case (kappa = 0.77 [p < 0.0001]). Conclusions: Almost perfect agreement existed in the GTV of these two representative cases. Tshere was no significant disagreement in the CTV of the lower extremity, but variation in the CTV of upper extremity was seen, perhaps related to the positional differences between the planning CT and the diagnostic MRI.

  17. Variation in the Gross Tumor Volume and Clinical Target Volume for Preoperative Radiotherapy of Primary Large High-Grade Soft Tissue Sarcoma of the Extremity Among RTOG Sarcoma Radiation Oncologists

    International Nuclear Information System (INIS)

    Purpose: To evaluate variability in the definition of preoperative radiotherapy gross tumor volume (GTV) and clinical target volume (CTV) delineated by sarcoma radiation oncologists. Methods and Materials: Extremity sarcoma planning CT images along with the corresponding diagnostic MRI from two patients were distributed to 10 Radiation Therapy Oncology Group sarcoma radiation oncologists with instructions to define GTV and CTV using standardized guidelines. The CT data with contours were then returned for central analysis. Contours representing statistically corrected 95% (V95) and 100% (V100) agreement were computed for each structure. Results: For the GTV, the minimum, maximum, mean (SD) volumes (mL) were 674, 798, 752 ± 35 for the lower extremity case and 383, 543, 447 ± 46 for the upper extremity case. The volume (cc) of the union, V95 and V100 were 882, 761, and 752 for the lower, and 587, 461, and 455 for the upper extremity, respectively. The overall GTV agreement was judged to be almost perfect in both lower and upper extremity cases (kappa = 0.9 [p < 0.0001] and kappa = 0.86 [p < 0.0001]). For the CTV, the minimum, maximum, mean (SD) volumes (mL) were 1145, 1911, 1605 ± 211 for the lower extremity case and 637, 1246, 1006 ± 180 for the upper extremity case. The volume (cc) of the union, V95, and V100 were 2094, 1609, and 1593 for the lower, and 1533, 1020, and 965 for the upper extremity cases, respectively. The overall CTV agreement was judged to be almost perfect in the lower extremity case (kappa = 0.85 [p < 0.0001]) but only substantial in the upper extremity case (kappa = 0.77 [p < 0.0001]). Conclusions: Almost perfect agreement existed in the GTV of these two representative cases. Tshere was no significant disagreement in the CTV of the lower extremity, but variation in the CTV of upper extremity was seen, perhaps related to the positional differences between the planning CT and the diagnostic MRI.

  18. Impact of 18-fluorodeoxyglucose positron emission tomography on computed tomography defined target volumes in radiation treatment planning of esophageal cancer : reduction in geographic misses with equal inter-observer variability

    NARCIS (Netherlands)

    Schreurs, Liesbeth; Busz, D. M.; Paardekooper, G. M. R. M.; Beukema, J. C.; Jager, P. L.; Van der Jagt, E. J.; van Dam, G. M.; Groen, H.; Plukker, J. Th. M.; Langendijk, J. A.

    2010-01-01

    P>Target volume definition in modern radiotherapy is based on planning computed tomography (CT). So far, 18-fluorodeoxyglucose positron emission tomography (FDG-PET) has not been included in planning modality in volume definition of esophageal cancer. This study evaluates fusion of FDG-PET and CT in

  19. Development of whole-building energy design targets for commercial buildings: Phase 1, Planning: Volume 1, Final report

    Energy Technology Data Exchange (ETDEWEB)

    Crawley, D.B.; Briggs, R.S.; Jones, J.W.; Seaton, W.W.; Kaufman, J.E.; Deringer, J.J.; Kennett, E.W.

    1987-04-01

    This report describes background research for preparation of a plan for development of whole-building energy targets for new commercial buildings. The lead laboratory for this program is the Pacific Northwest Laboratory. A wide variety of expertise and resources from industry, academia, other government entities, and other DOE laboratories are used in planning, reviewing and conducting research activities. Cooperative and complementary research development, and technology transfer activities with other interested organizations are actively pursued.

  20. Dose distribution assessment (comparison) in the target volume treated with VMAT given by the planning system and evaluated by TL dosimeters

    International Nuclear Information System (INIS)

    Volumetric-modulated arc therapy (VMAT) is a relatively new therapy technique in which treatment is delivered using a cone beam that rotates around the patient. The radiation is delivered in a continuous gantry rotation while the cone beam is modulated by the intertwining of dynamic multileaf collimators (MLCs). Studies of VMAT plans have shown reduction in the treatment delivery time and monitor units (MU) comparable to IMRT plans improving major comfort to the patient and reducing uncertainties associated with patient movement during treatment. The treatment using VMAT minimizes the biological effects of radiation to critical structures near to the target volumes and produces excellent dose distributions. The dosimetry of ionizing radiation is essential for the radiological protection programs for quality assurance and licensing of equipment. For radiation oncology a quality assurance program is essentially to maintain the quality of patient care. As the VMAT is a new technique of radiation therapy it is important to optimize quality assurance mechanisms to ensure that tests are performed in order to preserve the patient and the equipment. This paper aims to determinate the dose distribution in the target volume (tumor to be treated) and the scattered dose distribution in the risk organs for VMAT technique comparing data given by the planning system and thermoluminescent (TL) response. (author)

  1. A comparison of perfusion computed tomography and contrast enhanced computed tomography on radiation target volume delineation using rabbit VX2 brain tumor model

    International Nuclear Information System (INIS)

    Objective: To compare the accuracy of blood volume perfusion imaging (perfusion CT)with contrast enhanced 64-slice spiral computed tomography (CECT) in the evaluation of gross tumor volume (GTV) and clinical target volume (CTV) using rabbits with VX2 brain tumor. Methods: Perfusion CT and CECT were performed in 20 rabbits with VX2 brain tumor. The GTV and CTV calculated with the maximal and minimal diameter of each tumor in the blood volume (BV) maps and CECT were measured and compared to those in pathological specimens. Results: The mean value of the maximal and minimal diameter of GTV was (8.19 ± 2.29) mm and (4.83 ± 1.31) mm in pathological specimens, (11.98 ±3.29) mm and (7.03±1.82) mm in BV maps, while (6.36±3.85) mm and (3.17±1.93) mm in CECT images, which were significantly different (pathological specimen vs. BV map, t = 7.17, P =0.000;pathological specimen vs. CECT, t = 8.37, P = 0.000, respectively). The mean value of the maximal and minimal diameter of CTV in pathologic specimens was (12.87 ± 3.74) mm and (7.71 ± 2.15) mm, which was significantly different from that of GTV and CTV in CECT (t = - 3. 18, P = 0. 005 and t = - 4.24, P =0.000; t= -11.59,P=0.000 and t= -9.39, P=0.000), while similar with that of GTV in BV maps (t = - 1.95,P = 0. 067; t = - 2. 06, P = 0. 054). For CECT, the margin from GTV to CTV was 81.83% ±40.33% for the maximal diameter and 276.73% ± 131.46% for the minimal. While for BV maps, the margin was 7.93% ± 17. 84% and 12.52% ± 27. 83%, which was significant different from that for CECT images (t=7.36, P=0. 000 and t= -8.78, P=0.000). Conclusions: Compared with CECT, the BV map from 64-slice spiral CT perfusion imaging might have higher accuracy in target volume delineation for brain tumor. (authors)

  2. Quantitative assessment of inter-observer variability in target volume delineation on stereotactic radiotherapy treatment for pituitary adenoma and meningioma near optic tract

    Directory of Open Access Journals (Sweden)

    Aibe Norihiro

    2011-01-01

    Full Text Available Abstract Background To assess inter-observer variability in delineating target volume and organs at risk in benign tumor adjacent to optic tract as a quality assurance exercise. Methods We quantitatively analyzed 21 plans made by 11 clinicians in seven CyberKnife centers. The clinicians were provided with a raw data set (pituitary adenoma and meningioma including clinical information, and were asked to delineate the lesions and create a treatment plan. Their contouring and plans (10 adenoma and 11 meningioma plans, were then compared. In addition, we estimated the influence of differences in contouring by superimposing the respective contours onto a default plan. Results The median planning target volume (PTV and the ratio of the largest to the smallest contoured volume were 9.22 cm3 (range, 7.17 - 14.3 cm3 and 1.99 for pituitary adenoma, and 6.86 cm3 (range 6.05 - 14.6 cm3 and 2.41 for meningioma. PTV volume was 10.1 ± 1.74 cm3 for group 1 with a margin of 1 -2 mm around the CTV (n = 3 and 9.28 ± 1.8 cm3(p = 0.51 for group 2 with no margin (n = 7 in pituitary adenoma. In meningioma, group 1 showed larger PTV volume (10.1 ± 3.26 cm3 than group 2 (6.91 ± 0.7 cm3, p = 0.03. All submitted plan keep the irradiated dose to optic tract within the range of 50 Gy (equivalent total doses in 2 Gy fractionation. However, contours superimposed onto the dose distribution of the default plan indicated that an excessive dose 23.64 Gy (up to 268% of the default plan in pituitary adenoma and 24.84 Gy (131% of the default plan in meningioma to the optic nerve in the contours from different contouring. Conclusion Quality assurance revealed inter-observer variability in contour delineation and their influences on planning for pituitary adenoma and meningioma near optic tract.

  3. Quantitative assessment of inter-observer variability in target volume delineation on stereotactic radiotherapy treatment for pituitary adenoma and meningioma near optic tract

    International Nuclear Information System (INIS)

    To assess inter-observer variability in delineating target volume and organs at risk in benign tumor adjacent to optic tract as a quality assurance exercise. We quantitatively analyzed 21 plans made by 11 clinicians in seven CyberKnife centers. The clinicians were provided with a raw data set (pituitary adenoma and meningioma) including clinical information, and were asked to delineate the lesions and create a treatment plan. Their contouring and plans (10 adenoma and 11 meningioma plans), were then compared. In addition, we estimated the influence of differences in contouring by superimposing the respective contours onto a default plan. The median planning target volume (PTV) and the ratio of the largest to the smallest contoured volume were 9.22 cm3 (range, 7.17 - 14.3 cm3) and 1.99 for pituitary adenoma, and 6.86 cm3 (range 6.05 - 14.6 cm3) and 2.41 for meningioma. PTV volume was 10.1 ± 1.74 cm3 for group 1 with a margin of 1 -2 mm around the CTV (n = 3) and 9.28 ± 1.8 cm3(p = 0.51) for group 2 with no margin (n = 7) in pituitary adenoma. In meningioma, group 1 showed larger PTV volume (10.1 ± 3.26 cm3) than group 2 (6.91 ± 0.7 cm3, p = 0.03). All submitted plan keep the irradiated dose to optic tract within the range of 50 Gy (equivalent total doses in 2 Gy fractionation). However, contours superimposed onto the dose distribution of the default plan indicated that an excessive dose 23.64 Gy (up to 268% of the default plan) in pituitary adenoma and 24.84 Gy (131% of the default plan) in meningioma to the optic nerve in the contours from different contouring. Quality assurance revealed inter-observer variability in contour delineation and their influences on planning for pituitary adenoma and meningioma near optic tract

  4. Target volume definition for 18F-FDG PET-positive lymph nodes in radiotherapy of patients with non-small cell lung cancer

    International Nuclear Information System (INIS)

    FDG PET is increasingly used in radiotherapy planning. Recently, we demonstrated substantial differences in target volumes when applying different methods of FDG-based contouring in primary lung tumours (Nestle et al., J Nucl Med 2005;46:1342-8). This paper focusses on FDG-positive mediastinal lymph nodes (LNPET). In our institution, 51 NSCLC patients who were candidates for radiotherapy prospectively underwent staging FDG PET followed by a thoracic PET scan in the treatment position and a planning CT. Eleven of them had 32 distinguishable non-confluent mediastinal or hilar nodal FDG accumulations (LNPET). For these, sets of gross tumour volumes (GTVs) were generated at both acquisition times by four different PET-based contouring methods (visual: GTVvis; 40% SUVmax: GTV40; SUV=2.5: GTV2.5; target/background (T/B) algorithm: GTVbg). All differences concerning GTV sizes were within the range of the resolution of the PET system. The detectability and technical delineability of the GTVs were significantly better in the late scans (e.g. p 0.02 for diagnostic application of SUVmax = 2.5; p = 0.0001 for technical delineability by GTV2.5; p = 0.003 by GTV40), favouring the GTVbg method owing to satisfactory overall applicability and independence of GTVs from acquisition time. Compared with CT, the majority of PET-based GTVs were larger, probably owing to resolution effects, with a possible influence of lesion movements. For nodal GTVs, different methods of contouring did not lead to clinically relevant differences in volumes. However, there were significant differences in technical delineability, especially after early acquisition. Overall, our data favour a late acquisition of FDG PET scans for radiotherapy planning, and the use of a T/B algorithm for GTV contouring. (orig.)

  5. Toward Semi-automated Assessment of Target Volume Delineation in Radiotherapy Trials: The SCOPE 1 Pretrial Test Case

    Energy Technology Data Exchange (ETDEWEB)

    Gwynne, Sarah, E-mail: Sarah.Gwynne2@wales.nhs.uk [Department of Clinical Oncology, Velindre Cancer Centre, Cardiff, Wales (United Kingdom); Spezi, Emiliano; Wills, Lucy [Department of Medical Physics, Velindre Cancer Centre, Cardiff, Wales (United Kingdom); Nixon, Lisette; Hurt, Chris [Wales Cancer Trials Unit, School of Medicine, Cardiff University, Cardiff, Wales (United Kingdom); Joseph, George [Department of Diagnostic Radiology, Velindre Cancer Centre, Cardiff, Wales (United Kingdom); Evans, Mererid [Department of Clinical Oncology, Velindre Cancer Centre, Cardiff, Wales (United Kingdom); Griffiths, Gareth [Wales Cancer Trials Unit, School of Medicine, Cardiff University, Cardiff, Wales (United Kingdom); Crosby, Tom [Department of Clinical Oncology, Velindre Cancer Centre, Cardiff, Wales (United Kingdom); Staffurth, John [Division of Cancer, School of Medicine, Cardiff University, Cardiff, Wales (United Kingdom)

    2012-11-15

    Purpose: To evaluate different conformity indices (CIs) for use in the analysis of outlining consistency within the pretrial quality assurance (Radiotherapy Trials Quality Assurance [RTTQA]) program of a multicenter chemoradiation trial of esophageal cancer and to make recommendations for their use in future trials. Methods and Materials: The National Cancer Research Institute SCOPE 1 trial is an ongoing Cancer Research UK-funded phase II/III randomized controlled trial of chemoradiation with capecitabine and cisplatin with or without cetuximab for esophageal cancer. The pretrial RTTQA program included a detailed radiotherapy protocol, an educational package, and a single mid-esophageal tumor test case that were sent to each investigator to outline. Investigator gross tumor volumes (GTVs) were received from 50 investigators in 34 UK centers, and CERR (Computational Environment for Radiotherapy Research) was used to perform an assessment of each investigator GTV against a predefined gold-standard GTV using different CIs. A new metric, the local conformity index (l-CI), that can localize areas of maximal discordance was developed. Results: The median Jaccard conformity index (JCI) was 0.69 (interquartile range, 0.62-0.70), with 14 of 50 investigators (28%) achieving a JCI of 0.7 or greater. The median geographical miss index was 0.09 (interquartile range, 0.06-0.16), and the mean discordance index was 0.27 (95% confidence interval, 0.25-0.30). The l-CI was highest in the middle section of the volume, where the tumor was bulky and more easily definable, and identified 4 slices where fewer than 20% of investigators achieved an l-CI of 0.7 or greater. Conclusions: The available CIs analyze different aspects of a gold standard-observer variation, with JCI being the most useful as a single metric. Additional information is provided by the l-CI and can focus the efforts of the RTTQA team in these areas, possibly leading to semi-automated outlining assessment.

  6. Methodological approaches to planar and volumetric scintigraphic imaging of small volume targets with high spatial resolution and sensitivity

    International Nuclear Information System (INIS)

    Single-photon emission computed tomography (SPECT) is a non-invasive imaging technique, which provides information reporting the functional states of tissues. SPECT imaging has been used as a diagnostic tool in several human disorders and can be used in animal models of diseases for physiopathological, genomic and drug discovery studies. However, most of the experimental models used in research involve rodents, which are at least one order of magnitude smaller in linear dimensions than man. Consequently, images of targets obtained with conventional gamma-cameras and collimators have poor spatial resolution and statistical quality. We review the methodological approaches developed in recent years in order to obtain images of small targets with good spatial resolution and sensitivity. Multi pinhole, coded mask- and slit-based collimators are presented as alternative approaches to improve image quality. In combination with appropriate decoding algorithms, these collimators permit a significant reduction of the time needed to register the projections used to make 3-D representations of the volumetric distribution of target's radiotracers. Simultaneously, they can be used to minimize artifacts and blurring arising when single pinhole collimators are used. Representation images are presented, which illustrate the use of these collimators. We also comment on the use of coded masks to attain tomographic resolution with a single projection, as discussed by some investigators since their introduction to obtain near-field images. We conclude this review by showing that the use of appropriate hardware and software tools adapted to conventional gamma-cameras can be of great help in obtaining relevant functional information in experiments using small animals. (author)

  7. Methodological approaches to planar and volumetric scintigraphic imaging of small volume targets with high spatial resolution and sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Mejia, J.; Galvis-Alonso, O.Y. [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Faculdade de Medicina. Dept. de Biologia Molecular], e-mail: mejia_famerp@yahoo.com.br; Braga, J. [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Div. de Astrofisica; Correa, R. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Div. de Ciencia Espacial e Atmosferica; Leite, J.P. [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Dept. de Neurologia, Psiquiatria e Psicologia Medica; Simoes, M.V. [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Dept. de Clinica Medica

    2009-08-15

    Single-photon emission computed tomography (SPECT) is a non-invasive imaging technique, which provides information reporting the functional states of tissues. SPECT imaging has been used as a diagnostic tool in several human disorders and can be used in animal models of diseases for physiopathological, genomic and drug discovery studies. However, most of the experimental models used in research involve rodents, which are at least one order of magnitude smaller in linear dimensions than man. Consequently, images of targets obtained with conventional gamma-cameras and collimators have poor spatial resolution and statistical quality. We review the methodological approaches developed in recent years in order to obtain images of small targets with good spatial resolution and sensitivity. Multi pinhole, coded mask- and slit-based collimators are presented as alternative approaches to improve image quality. In combination with appropriate decoding algorithms, these collimators permit a significant reduction of the time needed to register the projections used to make 3-D representations of the volumetric distribution of target's radiotracers. Simultaneously, they can be used to minimize artifacts and blurring arising when single pinhole collimators are used. Representation images are presented, which illustrate the use of these collimators. We also comment on the use of coded masks to attain tomographic resolution with a single projection, as discussed by some investigators since their introduction to obtain near-field images. We conclude this review by showing that the use of appropriate hardware and software tools adapted to conventional gamma-cameras can be of great help in obtaining relevant functional information in experiments using small animals. (author)

  8. A New Brain Positron Emission Tomography Scanner With Semiconductor Detectors for Target Volume Delineation and Radiotherapy Treatment Planning in Patients With Nasopharyngeal Carcinoma

    International Nuclear Information System (INIS)

    Purpose: We compared two treatment planning methods for stereotactic boost for treating nasopharyngeal carcinoma (NPC): the use of conventional whole-body bismuth germanate (BGO) scintillator positron emission tomography (PETCONVWB) versus the new brain (BR) PET system using semiconductor detectors (PETNEWBR). Methods and Materials: Twelve patients with NPC were enrolled in this study. [18F]Fluorodeoxyglucose-PET images were acquired using both the PETNEWBR and the PETCONVWB system on the same day. Computed tomography (CT) and two PET data sets were transferred to a treatment planning system, and the PETCONVWB and PETNEWBR images were coregistered with the same set of CT images. Window width and level values for all PET images were fixed at 3000 and 300, respectively. The gross tumor volume (GTV) was visually delineated on PET images by using either PETCONVWB (GTVCONV) images or PETNEWBR (GTVNEW) images. Assuming a stereotactic radiotherapy boost of 7 ports, the prescribed dose delivered to 95% of the planning target volume (PTV) was set to 2000 cGy in 4 fractions. Results: The average absolute volume (±standard deviation [SD]) of GTVNEW was 15.7 ml (±9.9) ml, and that of GTVCONV was 34.0 (±20.5) ml. The average GTVNEW was significantly smaller than that of GTVCONV (p = 0.0006). There was no statistically significant difference between the maximum dose (p = 0.0585) and the mean dose (p = 0.2748) of PTV. The radiotherapy treatment plan based on the new gross tumor volume (PLANNEW) significantly reduced maximum doses to the cerebrum and cerebellum (p = 0.0418) and to brain stem (p = 0.0041). Conclusion: Results of the present study suggest that the new brain PET system using semiconductor detectors can provide more accurate tumor delineation than the conventional whole-body BGO PET system and may be an important tool for functional and molecular radiotherapy treatment planning.

  9. Comparison of target volumes in radiotherapy defined on scanner and on PET-T.D.M. with 18F-F.D.G. in the frame of head and neck cancers

    International Nuclear Information System (INIS)

    The objective is to study in a prospective way, in the frame of head and neck cancers, the impact of the positron computed tomography with 18F fluorodeoxyglucose (PET-F.D.G.) on the limitation of target volumes in radiotherapy. In conclusions, the gross tumor volume (G.T.V.) defined on PET is smaller than this one defined on scanner, that could be interesting in radiotherapy, in the perspective of a dose escalation. In addition, areas of discordance exist between the clinical target volumes (C.T.V.70 and C.T.V.50) defined on PET and on scanner. These discordances, synonyms of under or over estimation of target volumes, could have important clinical consequences in term of local control and toxicity. (N.C.)

  10. Magnetic Resonance Imaging-Based Target Volume Delineation in Radiation Therapy Treatment Planning for Brain Tumors Using Localized Region-Based Active Contour

    International Nuclear Information System (INIS)

    Purpose: To evaluate the clinical application of a robust semiautomatic image segmentation method to determine the brain target volumes in radiation therapy treatment planning. Methods and Materials: A local robust region-based algorithm was used on MRI brain images to study the clinical target volume (CTV) of several patients. First, 3 oncologists delineated CTVs of 10 patients manually, and the process time for each patient was calculated. The averages of the oncologists’ contours were evaluated and considered as reference contours. Then, to determine the CTV through the semiautomatic method, a fourth oncologist who was blind to all manual contours selected 4-8 points around the edema and defined the initial contour. The time to obtain the final contour was calculated again for each patient. Manual and semiautomatic segmentation were compared using 3 different metric criteria: Dice coefficient, Hausdorff distance, and mean absolute distance. A comparison also was performed between volumes obtained from semiautomatic and manual methods. Results: Manual delineation processing time of tumors for each patient was dependent on its size and complexity and had a mean (±SD) of 12.33 ± 2.47 minutes, whereas it was 3.254 ± 1.7507 minutes for the semiautomatic method. Means of Dice coefficient, Hausdorff distance, and mean absolute distance between manual contours were 0.84 ± 0.02, 2.05 ± 0.66 cm, and 0.78 ± 0.15 cm, and they were 0.82 ± 0.03, 1.91 ± 0.65 cm, and 0.7 ± 0.22 cm between manual and semiautomatic contours, respectively. Moreover, the mean volume ratio (=semiautomatic/manual) calculated for all samples was 0.87. Conclusions: Given the deformability of this method, the results showed reasonable accuracy and similarity to the results of manual contouring by the oncologists. This study shows that the localized region-based algorithms can have great ability in determining the CTV and can be appropriate alternatives for manual approaches in brain cancer

  11. Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Akila N., E-mail: aviswanathan@lroc.harvard.edu [Brigham and Women' s Hospital/Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Erickson, Beth [Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Gaffney, David K. [University of Utah Huntsman Cancer Hospital, Salt Lake City, Utah (United States); Beriwal, Sushil [University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Bhatia, Sudershan K. [University of Iowa, Iowa City, Iowa (United States); Lee Burnett, Omer [University of Alabama, Birmingham, Alabama (United States); D' Souza, David P.; Patil, Nikhilesh [London Health Sciences Centre and Western University, London, Ontario (Canada); Haddock, Michael G. [Mayo Medical Center, Rochester, Minnesota (United States); Jhingran, Anuja [University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Jones, Ellen L. [University of North Carolina, Chapel Hill, North Carolina (United States); Kunos, Charles A. [Case Western Reserve University, Cleveland, Ohio (United States); Lee, Larissa J. [Brigham and Women' s Hospital/Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Lin, Lilie L. [University of Pennsylvania, Philadelphia, Pennsylvania (United States); Mayr, Nina A. [University of Washington, Seattle, Washington (United States); Petersen, Ivy [Mayo Medical Center, Rochester, Minnesota (United States); Petric, Primoz [Division of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana (Slovenia); Department of Radiation Oncology, National Center for Cancer Care and Research, Doha (Qatar); Portelance, Lorraine [University of Miami Miller School of Medicine, Miami, Florida (United States); Small, William [Loyola University Strich School of Medicine, Chicago, Illinois (United States); Strauss, Jonathan B. [The Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, Illinois (United States); and others

    2014-10-01

    Objective: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy. Methods and Materials: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case. Results: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR. Conclusion: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at (http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx)

  12. A Comparison of Amplitude-Based and Phase-Based Positron Emission Tomography Gating Algorithms for Segmentation of Internal Target Volumes of Tumors Subject to Respiratory Motion

    International Nuclear Information System (INIS)

    Purpose: To quantitatively compare the accuracy of tumor volume segmentation in amplitude-based and phase-based respiratory gating algorithms in respiratory-correlated positron emission tomography (PET). Methods and Materials: List-mode fluorodeoxyglucose-PET data was acquired for 10 patients with a total of 12 fluorodeoxyglucose-avid tumors and 9 lymph nodes. Additionally, a phantom experiment was performed in which 4 plastic butyrate spheres with inner diameters ranging from 1 to 4 cm were imaged as they underwent 1-dimensional motion based on 2 measured patient breathing trajectories. PET list-mode data were gated into 8 bins using 2 amplitude-based (equal amplitude bins [A1] and equal counts per bin [A2]) and 2 temporal phase-based gating algorithms. Gated images were segmented using a commercially available gradient-based technique and a fixed 40% threshold of maximum uptake. Internal target volumes (ITVs) were generated by taking the union of all 8 contours per gated image. Segmented phantom ITVs were compared with their respective ground-truth ITVs, defined as the volume subtended by the tumor model positions covering 99% of breathing amplitude. Superior-inferior distances between sphere centroids in the end-inhale and end-exhale phases were also calculated. Results: Tumor ITVs from amplitude-based methods were significantly larger than those from temporal-based techniques (P=.002). For lymph nodes, A2 resulted in ITVs that were significantly larger than either of the temporal-based techniques (P<.0323). A1 produced the largest and most accurate ITVs for spheres with diameters of ≥2 cm (P=.002). No significant difference was shown between algorithms in the 1-cm sphere data set. For phantom spheres, amplitude-based methods recovered an average of 9.5% more motion displacement than temporal-based methods under regular breathing conditions and an average of 45.7% more in the presence of baseline drift (P<.001). Conclusions: Target volumes in images generated

  13. Coregistration of Prechemotherapy PET-CT for Planning Pediatric Hodgkin's Disease Radiotherapy Significantly Diminishes Interobserver Variability of Clinical Target Volume Definition

    International Nuclear Information System (INIS)

    Purpose: To assess the interobserver variability in clinical target volume (CTV) definitions when using registered 18F-labeled deoxyglucose positron emission tomography (FDG-PET-CT) versus side-by-side image sets in pediatric Hodgkin's disease (HD). Methods and Materials: Prechemotherapy FDG-PET-CT scans performed in the treatment position were acquired from 20 children (median age, 14 years old) with HD (stages 2A to 4B) and registered with postchemotherapy planning CT scans. The patients had a median age of 14 years and stages of disease ranging between 2A and 4B. Image sets were coregistered using a semiautomatic coregistration system. The biological target volume was defined on all the coregistered images as a guide to defining the initial site of involvement and to avoid false-positive or negative results. Five radiation oncologists independently defined the CTV for all 20 patients: once using separate FDG-PET-CT images as a guide (not registered) to define CTVa and once using the registered FDG-PET-CT data to define CTVb. The total volumes were compared, as well as their coefficients of variation (COV). To assess the interobserver variability, the percentages of intersection between contours drawn by all observers for each patient were calculated for CTVa and for CTVb. Results: The registration of a prechemotherapy FDG-PET-CT scan caused a change in the CTV for all patients. Comparing CTVa with CTVb showed that the mean CTVb increased in 14 patients (range, 0.61%-101.96%) and decreased in 6 patients (range, 2.97%-37.26%). The COV for CTVb significantly decreased for each patient; the mean COVs for CTVa and CTVb were 45% (21%-65%) and 32% (13%-57%), respectively (p = 0.0004). The percentage of intersection among all CTVbs for the five observers increased significantly by 89.77% (1.99%-256.41%) compared to that of CTVa (p = 0.0001). Conclusions: High observer variability can occur during CT-based definition of CTVs for children diagnosed with HD. Registration

  14. Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

    International Nuclear Information System (INIS)

    Objective: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy. Methods and Materials: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case. Results: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR. Conclusion: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at (http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx)

  15. Reconstitution of internal target volumes by combining four-dimensional computed tomography and a modified slow computed tomography scan in stereotactic body radiotherapy planning for lung cancer

    International Nuclear Information System (INIS)

    To evaluate the volumetric and geometric differences in the ITVs generated by four-dimensional (4D) computed tomography (CT), a modified slow CT scan, and a combination of these CT methods in lung cancer patients treated with stereotactic body radiotherapy (SBRT). Both 4D CT and modified slow CT using a multi-slice CT scanner were performed for SBRT planning in 14 patients with 15 pulmonary targets. Volumetric and geometric analyses were performed for (1) ITVall, generated by combining the gross tumor volumes (GTVs) from all 8 phases of the 4D CT; (2) ITV2, generated by combining the GTVs from 2 extreme phases of the 4D CT; (3) ITVslow, derived from the GTV on the modified slow CT scan; (4) ITVall+slow, generated by combining ITVall and ITVslow; and (5) ITV2+slow, generated by combining ITV2 and ITVslow. Three SBRT plans were performed using 3 ITVs to assess the dosimetric effects on normal lung caused by the various target volumes. ITVall (11.8 ± 8.3 cm3) was significantly smaller than ITVall+slow (12.5 ± 8.9 cm3), with mean values of 5.8% for the percentage volume difference, and a mean of 7.5% of ITVslow was not encompassed in ITVall. The geometric coverages of ITV2 and ITVslow for ITVall were 84.7 ± 6.6% and 76.2 ± 9.3%, respectively, but the coverage for ITVall increased to 90.9 ± 5.9% by using the composite of these two ITVs. There were statistically significant increases in the lung-dose parameters of the plans based on ITVall+slow compared to the plans based on ITVall or ITV2+slow. However, the magnitudes of these differences were relatively small, with a value of less than 3% in all dosimetric parameters. Due to its ability to provides additional motion information, the combination of 4D CT and a modified slow CT scan in SBRT planning for lung cancer can be used to reduce possible errors in true target delineation caused by breathing pattern variations

  16. Contrast-enhanced magnetization transfer imaging: improvement of brain tumor conspicuity and delineation for radiosurgical target volume definition

    International Nuclear Information System (INIS)

    Purpose: To assess the contrast-noise-ratio (CNR), and thus tumor conspicuity and delineation, on contrast-enhanced T1-weighted magnetization transfer (MT) images compared to conventional T1-weighted spin echo (SE) images as a strategy to improve definition of the macroscopic boost volume in radiosurgery treatment planning in patients with high grade gliomas or metastatic brain lesions. Materials and methods: Fifty patients (mean age, 51 years) with histologically proven or suspected high grade glioma or cerebral metastases were prospectively examined by MR imaging. Following gadolinium dimeglumine administration (0.1 mmol/kg body weight) the brain was imaged with both a T1-weighted MT-fast low angle shot (FLASH) pulse sequence and with a conventional T1-weighted SE sequence without MT saturation. Lesion conspicuity, size and CNR were compared for both techniques. Results: The mean tumor diameter of malignant gliomas was significantly (P < 0.01) larger when measured on T1-weighted MT-FLASH images compared to T1-weighted SE images and was comparable for metastatic lesions. The mean CNR of enhancing lesions on T1-weighted MT-FLASH was 14 ± 5 compared to 10 ± 4 on SE images, representing a significant (P < 0.05) improvement. Lesion conspicuity and delineation was improved in 10 of 20 patients (50%) with high grade gliomas and in 15 of 30 patients (50%) with metastases. Additional contrast enhancing lesions were detected in 8 of 30 patients (27%) with metastases on MT-FLASH images. Lesion conspicuity was markedly improved in the posterior fossa. Discussion: Contrast-enhanced T1-weighted MT-FLASH images improve lesion detection and delineation in the planning process of radiosurgery in patients with intracranial high grade gliomas or metastases and may even alter the treatment approach

  17. SU-E-T-389: Effect of Interfractional Shoulder Motion On Low Neck Nodal Targets for Patients Treated Using Volume Modulated Arc Therapy (VMAT)

    Energy Technology Data Exchange (ETDEWEB)

    Casey, K; Wong, P; Tung, S [MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: To quantify the dosimetric impact of interfractional shoulder motion on targets in the low neck for head and neck patients treated with volume modulated arc therapy (VMAT). Methods: Three patients with head and neck cancer were selected. All three required treatment to nodal regions in the low neck in addition to the primary tumor. The patients were immobilized during simulation and treatment with a custom thermoplastic mask covering the head and shoulders. One VMAT plan was created for each patient utilizing two full 360° arcs. A second plan was created consisting of two superior VMAT arcs matched to an inferior static AP supraclavicular field. A CT-on-rails alignment verification was performed weekly during each patient's treatment course. The weekly CT images were registered to the simulation CT and the target contours were deformed and applied to the weekly CT. The two VMAT plans were copied to the weekly CT datasets and recalculated to obtain the dose to the low neck contours. Results: The average observed shoulder position shift in any single dimension relative to simulation was 2.5 mm. The maximum shoulder shift observed in a single dimension was 25.7 mm. Low neck target mean doses, normalized to simulation and averaged across all weekly recalculations were 0.996, 0.991, and 1.033 (Full VMAT plan) and 0.986, 0.995, and 0.990 (Half-Beam VMAT plan) for the three patients, respectively. The maximum observed deviation in target mean dose for any individual weekly recalculation was 6.5%, occurring with the Full VMAT plan for Patient 3. Conclusion: Interfractional variation in dose to low neck nodal regions was quantified for three head and neck patients treated with VMAT. Mean dose was 3.3% higher than planned for one patient using a Full VMAT plan. A Half-Beam technique is likely a safer choice when treating the supraclavicular region with VMAT.

  18. SU-E-T-389: Effect of Interfractional Shoulder Motion On Low Neck Nodal Targets for Patients Treated Using Volume Modulated Arc Therapy (VMAT)

    International Nuclear Information System (INIS)

    Purpose: To quantify the dosimetric impact of interfractional shoulder motion on targets in the low neck for head and neck patients treated with volume modulated arc therapy (VMAT). Methods: Three patients with head and neck cancer were selected. All three required treatment to nodal regions in the low neck in addition to the primary tumor. The patients were immobilized during simulation and treatment with a custom thermoplastic mask covering the head and shoulders. One VMAT plan was created for each patient utilizing two full 360° arcs. A second plan was created consisting of two superior VMAT arcs matched to an inferior static AP supraclavicular field. A CT-on-rails alignment verification was performed weekly during each patient's treatment course. The weekly CT images were registered to the simulation CT and the target contours were deformed and applied to the weekly CT. The two VMAT plans were copied to the weekly CT datasets and recalculated to obtain the dose to the low neck contours. Results: The average observed shoulder position shift in any single dimension relative to simulation was 2.5 mm. The maximum shoulder shift observed in a single dimension was 25.7 mm. Low neck target mean doses, normalized to simulation and averaged across all weekly recalculations were 0.996, 0.991, and 1.033 (Full VMAT plan) and 0.986, 0.995, and 0.990 (Half-Beam VMAT plan) for the three patients, respectively. The maximum observed deviation in target mean dose for any individual weekly recalculation was 6.5%, occurring with the Full VMAT plan for Patient 3. Conclusion: Interfractional variation in dose to low neck nodal regions was quantified for three head and neck patients treated with VMAT. Mean dose was 3.3% higher than planned for one patient using a Full VMAT plan. A Half-Beam technique is likely a safer choice when treating the supraclavicular region with VMAT

  19. Treatment of Non-Small Cell Lung Cancer (NSCLC) Using CT in Combination with a PET Examination to Minimize the Clinical Target Volume of the Mediastinum

    Institute of Scientific and Technical Information of China (English)

    Yusheng Shi; Xiaogang Deng; Longhua Chen

    2007-01-01

    OBJECTIVE To decrease radiation injury of the esophagus and lungs by utilizing a CT scan in combination with PET tumor imaging in order to minimize the clinical target area of locally advanced non-small cell lung cancer, without preventive radiation on the lymphatic drainage area. METHODS Of 76 patients with locally advanced non-small cell lung cancer (NSCLC), 32 received a PET examination before radiotherapy. Preventive radiation was not conducted in the mediastinum area without lymphatic metastasis, which was confirmed by CT and PET. For the other 44 patients, preventive radiation was performed in the lymphatic drainage area. PET examinations showed that the clinical target volume of the patients was decreased on average to about one third. The radiation therapy for patients of the two groups was the same, I.e. The dose for accelerated fractionated irradiation was 3 Gy/time and 5 time/week. The preventive dose was 42 to 45 Gy/time, 14 to 15 time/week, with 3-week treatment, and the therapeutic dose was 60 to 63 Gy/time, 20 to 21 time/week, with a period of 4 to 5 weeks.RESULTS The rate of missed lymph nodes beyond the irradiation field was 6.3% and 4.5% respectively in the group with and without PET examination (P = 0.831). The incidence of acute radioactive esophagitis was 15.6 % and 45.5% in the two groups respectively (P = 0.006). The incidence of acute radiation pneumonia and long-term pulmonary fibrosis in the two groups was 6.3% and 9.1%, and 68.8% and 75.0%, respectively (P = 0.982 and P = 0.547).CONCLUSION The recurrence rate in the lymph nodes beyond the target area was not increased after minimizing the clinical target volume (CTV), whereas radioactive injury to the lungs and esophageal injury was reduced, and especially with a significant decrease in the rate of acute radioactive esophagitis. The method of CT in combination with PET for minimizing the mediastinal CTV is superior to the conventional preventive radiation of the mediastinum.

  20. Beam specific planning target volumes incorporating 4DCT for pencil beam scanning proton therapy of thoracic tumors

    CERN Document Server

    Lin, Liyong; Huang, Sheng; Mayer, Rulon; Thomas, Andrew; Solberg, Timothy D; McDonough, James E; Simone, Charles B

    2015-01-01

    The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties and patient setup variations. Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4DCT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4DCT phases, using +-3% uncertainty in stopping power, and +-3 mm uncertainty in patient setup in each direction were used to create 8X12X10=960 PBS plans for the evaluation of ten patients. Plans were normalized to provide identical coverage between DS and PBS. The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and...

  1. PET/CT imaging for target volume delineation in curative intent radiotherapy of non-small cell lung cancer: IAEA consensus report 2014

    International Nuclear Information System (INIS)

    This document describes best practice and evidence based recommendations for the use of FDG-PET/CT for the purposes of radiotherapy target volume delineation (TVD) for curative intent treatment of non-small cell lung cancer (NSCLC). These recommendations have been written by an expert advisory group, convened by the International Atomic Energy Agency (IAEA) to facilitate a Coordinated Research Project (CRP) aiming to improve the applications of PET based radiation treatment planning (RTP) in low and middle income countries. These guidelines can be applied in routine clinical practice of radiotherapy TVD, for NSCLC patients treated with concurrent chemoradiation or radiotherapy alone, where FDG is used, and where a calibrated PET camera system equipped for RTP patient positioning is available. Recommendations are provided for PET and CT image visualization and interpretation, and for tumor delineation using planning CT with and without breathing motion compensation

  2. A Prospective Pathologic Study to Define the Clinical Target Volume for Partial Breast Radiation Therapy in Women With Early Breast Cancer

    International Nuclear Information System (INIS)

    Purpose: To determine an appropriate clinical target volume for partial breast radiation therapy (PBRT) based on the spatial distribution of residual invasive and in situ carcinoma after wide local excision (WLE) for early breast cancer or ductal carcinoma in situ (DCIS). Methods and Materials: We performed a prospective pathologic study of women potentially eligible for PBRT who had re-excision and/or completion mastectomy after WLE for early breast cancer or DCIS. A pathologic assessment protocol was used to determine the maximum radial extension (MRE) of residual carcinoma from the margin of the initial surgical cavity. Women were stratified by the closest initial radial margin width: negative (>1 mm), close (>0 mm and ≤1 mm), or involved. Results: The study population was composed of 133 women with a median age of 59 years (range, 27-82 years) and the following stage groups: 0 (13.5%), I (40.6%), II (38.3%), and III (7.5%). The histologic subtypes of the primary tumor were invasive ductal carcinoma (74.4%), invasive lobular carcinoma (12.0%), and DCIS alone (13.5%). Residual carcinoma was present in the re-excision and completion mastectomy specimens in 55.4%, 14.3%, and 7.2% of women with an involved, close, and negative margin, respectively. In the 77 women with a noninvolved radial margin, the MRE of residual disease, if present, was ≤10 mm in 97.4% (95% confidence interval 91.6-99.5) of cases. Larger MRE measurements were significantly associated with an involved margin (P30 mm (P=.03), premenopausal status (P=.03), and negative progesterone receptor status (P=.05). Conclusions: A clinical target volume margin of 10 mm would encompass microscopic residual disease in >90% of women potentially eligible for PBRT after WLE with noninvolved resection margins.

  3. A Prospective Pathologic Study to Define the Clinical Target Volume for Partial Breast Radiation Therapy in Women With Early Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Brandon T., E-mail: Brandon.Nguyen@act.gov.au [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Canberra Hospital, Radiation Oncology Department, Garran, ACT (Australia); Deb, Siddhartha [Department of Anatomical Pathology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Victorian Cancer Biobank, Cancer Council of Victoria, Carlton, Victoria (Australia); Fox, Stephen [Department of Anatomical Pathology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Hill, Prudence [Department of Anatomical Pathology, St. Vincent' s Hospital Melbourne, Fitzroy, Victoria (Australia); Collins, Marnie [Centre for Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Chua, Boon H. [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); University of Melbourne, Parkville, Victoria (Australia)

    2012-12-01

    Purpose: To determine an appropriate clinical target volume for partial breast radiation therapy (PBRT) based on the spatial distribution of residual invasive and in situ carcinoma after wide local excision (WLE) for early breast cancer or ductal carcinoma in situ (DCIS). Methods and Materials: We performed a prospective pathologic study of women potentially eligible for PBRT who had re-excision and/or completion mastectomy after WLE for early breast cancer or DCIS. A pathologic assessment protocol was used to determine the maximum radial extension (MRE) of residual carcinoma from the margin of the initial surgical cavity. Women were stratified by the closest initial radial margin width: negative (>1 mm), close (>0 mm and {<=}1 mm), or involved. Results: The study population was composed of 133 women with a median age of 59 years (range, 27-82 years) and the following stage groups: 0 (13.5%), I (40.6%), II (38.3%), and III (7.5%). The histologic subtypes of the primary tumor were invasive ductal carcinoma (74.4%), invasive lobular carcinoma (12.0%), and DCIS alone (13.5%). Residual carcinoma was present in the re-excision and completion mastectomy specimens in 55.4%, 14.3%, and 7.2% of women with an involved, close, and negative margin, respectively. In the 77 women with a noninvolved radial margin, the MRE of residual disease, if present, was {<=}10 mm in 97.4% (95% confidence interval 91.6-99.5) of cases. Larger MRE measurements were significantly associated with an involved margin (P<.001), tumor size >30 mm (P=.03), premenopausal status (P=.03), and negative progesterone receptor status (P=.05). Conclusions: A clinical target volume margin of 10 mm would encompass microscopic residual disease in >90% of women potentially eligible for PBRT after WLE with noninvolved resection margins.

  4. Development of RTOG Consensus Guidelines for the Definition of the Clinical Target Volume for Postoperative Conformal Radiation Therapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Purpose: To define a prostate fossa clinical target volume (PF-CTV) for Radiation Therapy Oncology Group (RTOG) trials using postoperative radiotherapy for prostate cancer. Methods and Materials: An RTOG-sponsored meeting was held to define an appropriate PF-CTV after radical prostatectomy. Data were presented describing radiographic failure patterns after surgery. Target volumes used in previous trials were reviewed. Using contours independently submitted by 13 radiation oncologists, a statistical imputation method derived a preliminary 'consensus' PF-CTV. Results: Starting from the model-derived CTV, consensus was reached for a CT image-based PF-CTV. The PF-CTV should extend superiorly from the level of the caudal vas deferens remnant to >8-12 mm inferior to vesicourethral anastomosis (VUA). Below the superior border of the pubic symphysis, the anterior border extends to the posterior aspect of the pubis and posteriorly to the rectum, where it may be concave at the level of the VUA. At this level, the lateral border extends to the levator ani. Above the pubic symphysis, the anterior border should encompass the posterior 1-2 cm of the bladder wall; posteriorly, it is bounded by the mesorectal fascia. At this level, the lateral border is the sacrorectogenitopubic fascia. Seminal vesicle remnants, if present, should be included in the CTV if there is pathologic evidence of their involvement. Conclusions: Consensus on postoperative PF-CTV for RT after prostatectomy was reached and is available as a CT image atlas on the RTOG website. This will allow uniformity in defining PF-CTV for clinical trials that include postprostatectomy RT.

  5. Adenocarcinoma of the Esophagogastric Junction: The Pattern of Metastatic Lymph Node Dissemination as a Rationale for Elective Lymphatic Target Volume Definition

    International Nuclear Information System (INIS)

    Purpose: Regional nodal metastasis after neoadjuvant chemoradiation of adenocarcinoma of the esophagogastric junction (AEG) predicts survival. We aimed to clarify the lymph node (LN) distribution of AEG according to location of the tumor mass and invasion of neighboring areas for the selection of radiotherapy planning target volume (PTV) margins. Methods and Materials: Patterns of regional spread were analyzed in pathology reports of 326 patients patients with AEG who had undergone primary resection, with ≥15 lymph nodes examined. Tumors were classified into AEG types based on endoscopy and pathology reports. Fisher's exact test was used to compare nodal disease and tumor characteristics. Pulmonary dose-volume histograms were tested in 8 patients. Results: Nodes were positive in 81% of T2 to T4 tumors. Type of AEG, tumor size, lymphovascular invasion, and grading significantly influenced nodal distribution. We found that marked esophageal invasion of AEG II/III significantly correlated with paraesophageal nodal disease, and T3 to T4 AEG II/III had a significant rate of splenic hilum/artery nodes. Middle and lower paraesophageal nodes should be treated in T2 to T4 AEG I and AEG II with ≥15 mm involvement above the Z-line, and T3 to T4 AEG II. The splenic hilum and artery nodes can be spared in T2 AEG tumors, especially Type I tumors. The influence of paraesophageal nodal treatment on the risk of postoperative pulmonary complications can be estimated from dose-volume histograms. Conclusions: Accurate pretherapeutic staging predicts the risk of subclinical nodal disease and should be used to select the appropriate radiotherapeutic PTV. Careful selection of the PTV can be used to maximize the therapeutic window in multimodal therapy for AEG

  6. Defining the target volume for post-operative radiotherapy after D2 dissection in gastric cancer by CT-based vessel-guided delineation

    International Nuclear Information System (INIS)

    Purpose: To determine the recurrent nodal gross tumor volume (rnGTV) based on CT-guided vascular structure to refine the clinical target volume (CTV) delineation in postoperative radiotherapy for advanced gastric cancer following radical gastrectomy with D2 dissection. Materials and methods: We retrospectively reviewed follow-up images from 91 patients with their first regional recurrence after D2 dissection in stage III gastric cancer with N3 disease. We defined rnGTV as recurrent nodes shown in follow-up CT images, in which one diagnostic radiologist with specialty of gastrointestinal tract investigated. We drew rnGTVs at the equivalent location based on the same vessels of reference comparing CT images to recurrence CT images. Results: We propose vessel-based locations of rnGTVs on CT images with axial and coronal views. We show different patterns of regional recurrence according to the location of primary gastric cancer using CT and digitally reconstructed radiograph (DRR) images. Frequently recurred sites, overlapped by more than five rnGTVs, are depicted in a DRR image. Conclusions: This study suggests vessel-based delineations of rnGTVs on CT images depending on nodal recurrence sites from follow-up images after D2 lymphadenectomy. Our results could help reduce the inter-observer variation of CTV delineation after D2 dissection in gastric cancer

  7. Target volume coverage and dose to organs at risk in prostate cancer patients. Dose calculation on daily cone-beam CT data sets

    International Nuclear Information System (INIS)

    On the basis of correct Hounsfield unit to electron density calibration, cone-beam computed tomography (CBCT) data provide the opportunity for retrospective dose recalculation in the patient. Therefore, the consequences of translational positioning corrections and of morphological changes in the patient anatomy can be quantified for prostate cancer patients. The organs at risk were newly contoured on the CBCT data sets of 7 patients so as to evaluate the actual applied dose. The daily dose to the planning target volume (PTV) was recalculated with and without the translation data, which result from the real patient repositioning. A CBCT-based dose recalculation with uncertainties less than 3 % is possible. The deviations between the planning CT and the CBCT without the translational positioning correction vector show an average dose difference of - 8 % inside the PTV. An inverse proportional relation between the mean bladder dose and the actual volume of the bladder could be established. The daily applied dose to the rectum is about 1-54 % higher than predicted by the planning CT. A dose calculation based on CBCT data is possible. The daily positioning correction of the patient is necessary to avoid an underdosage in the PTV. The new contouring of the organs at risk - the bladder and rectum - allows a better appraisal to be made of the total applied dose to these organs. (orig.)

  8. A Prospective Evaluation of Staging and Target Volume Definition of Lymph Nodes by 18FDG PET/CT in Patients With Squamous Cell Carcinoma of Thoracic Esophagus

    International Nuclear Information System (INIS)

    Purpose: To determine an optimal standardized uptake value (SUV) threshold for detecting lymph node (LN) metastases in esophageal cancer using 18F-Fluorodeoxyglucose positron emission tomography/computer tomography (18FDG PET/CT) and to define the resulting nodal target volume, using histopathology as a “gold standard.” Methods: Sixteen patients with esophageal squamous cell carcinoma who underwent radical esophagectomy and three-field LN dissection after 18FDG PET/CT and CT scans were enrolled into this study. Locations of LN groups were recorded according to a uniform LN map. Diagnostic performance of different SUV thresholds was assessed by receiver operating characteristic analysis. The optimal cutoff SUV was determined by plotting the false-negative rate (FNR) and false-positive rate (FPR), the sum of both error rates (FNR+FPR), and accuracy against a hypothetical SUV threshold. For each patient, nodal gross tumor volumes (GTVNs) were generated with CT alone (GTVNCT), PET/CT (GTVNPET), and pathologic data (GTVNpath). GTVNCT or GTVNPET was compared with GTVNpath by means of a conformity index (CI), which is the intersection of the two GTVNs divided by the sum of them minus the intersection, e.g., CICT and path = GTVNCT and path/(GTVNCT+ GTVNpath – GTVNCT and path). Results: LN metastases occurred in 21 LN groups among the 144 specimens taken from the 16 patients. The area under the receiver operating characteristic curve was 0.9017 ± 0.0410. The plot of error rates showed a minimum of FNR+FPR for an SUV of 2.36, at which the sensitivity, specificity, and accuracy were 76.19%, 95.93%, and 93.06%, respectively, whereas those of CT were 33.33%, 94.31%, and 85.42% (p values: 0.0117, 0.7539, and 0.0266). Mean GTVNCT, GTVNPET, and GTVNpath were 1.52 ± 2.38, 2.82 ± 4.51, and 2.68 ± 4.16cm3, respectively. Mean CICT and path and CIPET and path were 0.31 and 0.65 (p value = 0.0352). Conclusions: Diagnostic superiority of PET/CT at an SUV threshold of 2.36 over

  9. Dosimetric accuracy of a treatment planning system for actively scanned proton beams and small target volumes: Monte Carlo and experimental validation

    CERN Document Server

    Magro, G; Mairani, A; Mirandola, A; Panizza, D; Russo, S; Ferrari, A; Valvo, F; Fossati, P; Ciocca, M

    2015-01-01

    This study was performed to evaluate the accuracy of a commercial treatment planning system (TPS), in optimising proton pencil beam dose distributions for small targets of different sizes (5–30 mm side) located at increasing depths in water. The TPS analytical algorithm was benchmarked against experimental data and the FLUKA Monte Carlo (MC) code, previously validated for the selected beam-line. We tested the Siemens syngo® TPS plan optimisation module for water cubes fixing the configurable parameters at clinical standards, with homogeneous target coverage to a 2 Gy (RBE) dose prescription as unique goal. Plans were delivered and the dose at each volume centre was measured in water with a calibrated PTW Advanced Markus® chamber. An EBT3® film was also positioned at the phantom entrance window for the acquisition of 2D dose maps. Discrepancies between TPS calculated and MC simulated values were mainly due to the different lateral spread modeling and resulted in being related to the field-to-spot size r...

  10. Comparison of target volumes in radiotherapy defined on scanner and on PET-T.D.M. with {sup 18}F-F.D.G. in the frame of head and neck cancers; Comparaison des volumes cibles en radiotherapie definis sur scanner et sur TEP-TDM au 18F FDG dans le cadre des cancers de la tete et du cou

    Energy Technology Data Exchange (ETDEWEB)

    Henriques De Figueiredo, B.; Barret, O.; Allard, M.; Fernandez, P. [Service de medecine nucleaire, CHU de Pellegrin, Bordeaux, (France); Demeaux, H.; Maire, J.P.; Lagarde, P. [service de radiotherapie, hopital Saint-Andre, Bordeaux, (France); Kantor, G.; Richau, P. [departement de radiotherapie, institut Bergonie, Bordeaux, (France); De Mones Del Pujol, E. [service d' ORL, hopital Pellegrin, Bordeaux, (France)

    2009-05-15

    The objective is to study in a prospective way, in the frame of head and neck cancers, the impact of the positron computed tomography with {sup 18}F fluorodeoxyglucose (PET-F.D.G.) on the limitation of target volumes in radiotherapy. In conclusions, the gross tumor volume (G.T.V.) defined on PET is smaller than this one defined on scanner, that could be interesting in radiotherapy, in the perspective of a dose escalation. In addition, areas of discordance exist between the clinical target volumes (C.T.V.70 and C.T.V.50) defined on PET and on scanner. These discordances, synonyms of under or over estimation of target volumes, could have important clinical consequences in term of local control and toxicity. (N.C.)

  11. Feasibility of omitting clinical target volume for limited-disease small cell lung cancer treated with chemotherapy and intensity-modulated radiotherapy

    International Nuclear Information System (INIS)

    To analyze the feasibility of omitting clinical target volume (CTV) for limited small cell lung cancer treated with chemotherapy and intensity modulated radiotherapy. 89 patients were treated from January 1, 2008 to August 31, 2011, 54 cases were irradiated with target volume without CTV, and 35 cases were irradiated with CTV. Both arms were irradiated post chemotherapy tumor extent and omitted elective nodal irradiation; dose prescription was 95% PTV56-63 Gy/28-35 F/5.6-7 weeks. In the arm without CTV and arm with CTV, the local relapse rates were 16.7% and 17.1% (p = 0.586) respectively. In the arm without CTV, of the 9 patients with local relapse, 6 recurred in-field, 2 recurred in margin, 1 recurred out of field. In the arm with CTV, of the 6 patients with local relapse, 4 recurred in-field, 1 recurred in margin, 1 recurred out of field. The distant metastases rates were 42.6% and 51.4% (p = 0.274) respectively. Grade 3-4 hematological toxicity and radiation esophagitis had no statistically significant, but grade 3-4 radiation pneumonia was observed in only 7.4% in the arm without CTV, compared 22.9% in the arm with CTV (p = 0.040). The median survival in the arm without CTV had not reached, compared with 38 months in the with CTV arm. The l- years, 2- years, 3- years survival rates of the arm without CTV and the arm with CTV were 81.0%, 66.2%, 61.5% and 88.6%, 61.7%, 56.6% (p = 0.517). The multivariate analysis indicated that the distant metastases (p = 0.000) and PCI factor (p = 0.004) were significantly related to overall survival. Target delineation omitting CTV for limited-disease small cell lung cancer received IMRT was feasible. The distant metastases and PCI factor were significantly related to overall survival

  12. Potential impacts of OCS oil and gas activities on fisheries. Volume 1. Annotated bibliography and database descriptions for target species distribution and abundance studies. Section 1, Part 1. Final report. [Outer Continental Shelf

    Energy Technology Data Exchange (ETDEWEB)

    Tear, L.M.

    1989-10-01

    The purpose of the volume is to present an annotated bibliography of unpublished and grey literature related to the distribution and abundance of select species of finfish and shellfish along the coasts of the United States. The volume also includes descriptions of databases that contain information related to target species' distribution and abundance. An index is provided at the end of each section to help the reader locate studies or databases related to a particular species.

  13. Potential impacts of OCS oil and gas activities on fisheries. Volume 1. Annotated bibliography and data-base descriptions for target-species distribution and abundance studies. Section 2. Final report. [Outer Continental Shelf

    Energy Technology Data Exchange (ETDEWEB)

    Tear, L.M.

    1989-10-01

    The purpose of the volume is to present an annotated bibliography of unpublished and grey literature related to the distribution and abundance of select species of finfish and shellfish along the coasts of the United States. The volume also includes description of databases that contain information related to target species' distribution and abundance. An index is provided at the end of each section to help the reader locate studies or databases related to a particular species.

  14. Potential impacts of OCS oil and gas activities on fisheries. Volume 1. Annotated bibliography and database descriptions for target-species distribution and abundance studies. Section 1, Part 2. Final report. [Outer Continental Shelf

    Energy Technology Data Exchange (ETDEWEB)

    Tear, L.M.

    1989-10-01

    The purpose of the volume is to present an annotated bibliography of unpublished and grey literature related to the distribution and abundance of select species of finfish and shellfish along the coasts of the United States. The volume also includes descriptions of databases that contain information related to target species' distribution and abundance. An index is provided at the end of each section to help the reader locate studies or databases related to a particular species.

  15. Target volume definition in high-risk prostate cancer patients using sentinel node SPECT/CT and 18 F-choline PET/CT

    Directory of Open Access Journals (Sweden)

    Vees Hansjörg

    2012-08-01

    Full Text Available Abstract Background To assess the influence of sentinel lymph nodes (SNs SPECT/CT and 18 F-choline (18 F-FCH PET/CT in radiotherapy (RT treatment planning for prostate cancer patients with a high-risk for lymph node (LN involvement. Methods Twenty high-risk prostate cancer patients underwent a pelvic SPECT acquisition following a transrectal ultrasound guided injection of 99mTc-Nanocoll into the prostate. In all patients but one an 18 F-FCH PET/CT for RT treatment planning was performed. SPECT studies were coregistered with the respective abdominal CTs. Pelvic SNs localized on SPECT/CT and LN metastases detected by 18 F-FCH PET/CT were compared to standard pelvic clinical target volumes (CTV. Results A total of 104 pelvic SNs were identified on SPECT/CT (mean 5.2 SNs/patient; range 1–10. Twenty-seven SNs were located outside the standard pelvic CTV, 17 in the proximal common iliac and retroperitoneal regions above S1, 9 in the pararectal fat and 1 in the inguinal region. SPECT/CT succeeded to optimize the definition of the CTV and treatment plans in 6/20 patients due to the presence of pararectal SNs located outside the standard treatment volume. 18 F-FCH PET/CT identified abnormal tracer uptake in the iliac LN region in 2/19 patients. These abnormal LNs were negative on SPECT/CT suggesting a potential blockade of lymphatic drainage by metastatic LNs with a high tumour burden. Conclusions Multimodality imaging which combines SPECT/CT prostate lymphoscintigraphy and 18 F-FCH PET/CT identified SNs outside standard pelvic CTVs or highly suspicious pelvic LNs in 40% of high-risk prostate cancer patients, highlighting the potential impact of this approach in RT treatment planning.

  16. Target volume definition in high-risk prostate cancer patients using sentinel node SPECT/CT and 18 F-choline PET/CT

    International Nuclear Information System (INIS)

    To assess the influence of sentinel lymph nodes (SNs) SPECT/CT and 18 F-choline (18 F-FCH) PET/CT in radiotherapy (RT) treatment planning for prostate cancer patients with a high-risk for lymph node (LN) involvement. Twenty high-risk prostate cancer patients underwent a pelvic SPECT acquisition following a transrectal ultrasound guided injection of 99mTc-Nanocoll into the prostate. In all patients but one an 18 F-FCH PET/CT for RT treatment planning was performed. SPECT studies were coregistered with the respective abdominal CTs. Pelvic SNs localized on SPECT/CT and LN metastases detected by 18 F-FCH PET/CT were compared to standard pelvic clinical target volumes (CTV). A total of 104 pelvic SNs were identified on SPECT/CT (mean 5.2 SNs/patient; range 1–10). Twenty-seven SNs were located outside the standard pelvic CTV, 17 in the proximal common iliac and retroperitoneal regions above S1, 9 in the pararectal fat and 1 in the inguinal region. SPECT/CT succeeded to optimize the definition of the CTV and treatment plans in 6/20 patients due to the presence of pararectal SNs located outside the standard treatment volume. 18 F-FCH PET/CT identified abnormal tracer uptake in the iliac LN region in 2/19 patients. These abnormal LNs were negative on SPECT/CT suggesting a potential blockade of lymphatic drainage by metastatic LNs with a high tumour burden. Multimodality imaging which combines SPECT/CT prostate lymphoscintigraphy and 18 F-FCH PET/CT identified SNs outside standard pelvic CTVs or highly suspicious pelvic LNs in 40% of high-risk prostate cancer patients, highlighting the potential impact of this approach in RT treatment planning

  17. Inter-observer variability of clinical target volume delineation in radiotherapy treatment of pancreatic cancer: a multi-institutional contouring experience

    International Nuclear Information System (INIS)

    An observational multi-institutional study has been conducted aimed to evaluate the inter-observer variability in clinical target volume (CTV) delineation among different radiation oncologists in radiotherapy treatment of pancreatic cancer. A multi-institutional contouring dummy-run of two different cases of pancreatic cancer treated by postoperative and preoperative radiotherapy (RT) was performed. Clinical history, diagnostics, and planning CT imaging were available on AIRO website. Participants were requested to delineate CTVs according to their skills and knowledge. Aiming to quantify interobserver variability of CTVs delineations, the total volume, craniocaudal, laterolateral, and anteroposterior diameters were calculated. Descriptive statistic was calculated. The 95% Confidence Interval (95% CI) for coefficient of variation (CV) was estimated. The Dice Similarity Index (DSI) was used to evaluate the spatial overlap accuracy of the different CTVs compared with the CTVs of a national reference Centre considered as a benchmark. The mean DSI (mDSI) was calculated and reported. A total of 18 radiation oncologists from different Institutes submitted the targets. Less variability was observed for the Elective CTV rather than the Boost CTV, in both cases. The estimated CV were 28.8% (95% CI: 21.2 - 45.0%) and 20.0% (95% CI: 14.9 - 30.6%) for the Elective CTV, in adjuvant (Case 1) and neoadjuvant (Case 2) case, respectively. The mDSI value was 0.68 for the Elective CTVs in both cases (range 0.19 - 0.79 in postoperative vs range 0.35 - 0.79 in preoperative case). The mDSI was increased to 0.71 (Case 1) and 0.72 (Case 2) if the observers with a worse agreement have been excluded. On the other hand, a CV of 42.4% (95% CI: 30.1 - 72.4%) and 63.8% (95% CI: 43.9 - 119.2%) with a mDSI value of 0.44 and 0.52, were calculated for the Boost CTV in Case 1 and Case 2, respectively. The CV and mDSI obtained values for Elective CTVs showed an acceptable agreement among participants

  18. SU-E-T-480: Radiobiological Dose Comparison of Single Fraction SRS, Multi-Fraction SRT and Multi-Stage SRS of Large Target Volumes Using the Linear-Quadratic Formula

    Energy Technology Data Exchange (ETDEWEB)

    Ding, C; Hrycushko, B; Jiang, S; Meyer, J; Timmerman, R [UT Southwestern Medical Center, Dallas, TX (United States)

    2014-06-01

    Purpose: To compare the radiobiological effect on large tumors and surrounding normal tissues from single fraction SRS, multi-fractionated SRT, and multi-staged SRS treatment. Methods: An anthropomorphic head phantom with a centrally located large volume target (18.2 cm{sup 3}) was scanned using a 16 slice large bore CT simulator. Scans were imported to the Multiplan treatment planning system where a total prescription dose of 20Gy was used for a single, three staged and three fractionated treatment. Cyber Knife treatment plans were inversely optimized for the target volume to achieve at least 95% coverage of the prescription dose. For the multistage plan, the target was segmented into three subtargets having similar volume and shape. Staged plans for individual subtargets were generated based on a planning technique where the beam MUs of the original plan on the total target volume are changed by weighting the MUs based on projected beam lengths within each subtarget. Dose matrices for each plan were export in DICOM format and used to calculate equivalent dose distributions in 2Gy fractions using an alpha beta ratio of 10 for the target and 3 for normal tissue. Results: Singe fraction SRS, multi-stage plan and multi-fractionated SRT plans had an average 2Gy dose equivalent to the target of 62.89Gy, 37.91Gy and 33.68Gy, respectively. The normal tissue within 12Gy physical dose region had an average 2Gy dose equivalent of 29.55Gy, 16.08Gy and 13.93Gy, respectively. Conclusion: The single fraction SRS plan had the largest predicted biological effect for the target and the surrounding normal tissue. The multi-stage treatment provided for a more potent biologically effect on target compared to the multi-fraction SRT treatments with less biological normal tissue than single-fraction SRS treatment.

  19. Suspect screening and target quantification of multi-class pharmaceuticals in surface water based on large-volume injection liquid chromatography and time-of-flight mass spectrometry.

    Science.gov (United States)

    Vergeynst, Leendert; Van Langenhove, Herman; Joos, Pieter; Demeestere, Kristof

    2014-04-01

    The ever-growing number of emerging micropollutants such as pharmaceuticals requests rapid and sensitive full-spectrum analytical techniques. Time-of-flight high-resolution mass spectrometry (TOF-HRMS) is a promising alternative for the state-of-the-art tandem mass spectrometry instruments because of its ability to simultaneously screen for a virtually unlimited number of suspect analytes and to perform target quantification. The challenge for such suspect screening is to develop a strategy, which minimizes the false-negative rate without restraining numerous false-positives. At the same time, omitting laborious sample enrichment through large-volume injection ultra-performance liquid chromatography (LVI-UPLC) avoids selective preconcentration. A suspect screening strategy was developed using LVI-UPLC-TOF-MS aiming the detection of 69 multi-class pharmaceuticals in surface water without the a priori availability of analytical standards. As a novel approach, the screening takes into account the signal-intensity-dependent accurate mass error of TOF-MS, hereby restraining 95 % of the measured suspect pharmaceuticals present in surface water. Application on five Belgian river water samples showed the potential of the suspect screening approach, as exemplified by a false-positive rate not higher than 15 % and given that 30 out of 37 restrained suspect compounds were confirmed by the retention time of analytical standards. Subsequently, this paper discusses the validation and applicability of the LVI-UPLC full-spectrum HRMS method for target quantification of the 69 pharmaceuticals in surface water. Analysis of five Belgian river water samples revealed the occurrence of 17 pharmaceuticals in a concentration range of 17 ng L(-1) up to 3.1 μg L(-1). PMID:24633561

  20. Radiation Therapy Oncology Group Consensus Panel Guidelines for the Delineation of the Clinical Target Volume in the Postoperative Treatment of Pancreatic Head Cancer

    International Nuclear Information System (INIS)

    Purpose: To develop contouring guidelines to be used in the Radiation Therapy Oncology Group protocol 0848, a Phase III randomized trial evaluating the benefit of adjuvant chemoradiation in patients with resected head of pancreas cancer. Methods and Materials: A consensus committee of six radiation oncologists with expertise in gastrointestinal radiotherapy developed stepwise contouring guidelines and an atlas for the delineation of the clinical target volume (CTV) in the postoperative treatment of pancreas cancer, based on identifiable regions of interest and margin expansions. Areas at risk for subclinical disease to be included in the CTV were defined, including nodal regions, anastomoses, and the preoperative primary tumor location. Regions of interest that could be reproducibly contoured on postoperative imaging after a pancreaticoduodenectomy were identified. Standardized expansion margins to encompass areas at risk were developed after multiple iterations to determine the optimal margin expansions. Results: New contouring recommendations based on CT anatomy were established. Written guidelines for the delineation of the postoperative CTV and normal tissues, as well as a Web-based atlas, were developed. Conclusions: The postoperative abdomen has been a difficult area for effective radiotherapy. These new guidelines will help physicians create fields that better encompass areas at risk and minimize dose to normal tissues.

  1. Skin Cancer of the Head and Neck With Perineural Invasion: Defining the Clinical Target Volumes Based on the Pattern of Failure

    International Nuclear Information System (INIS)

    Purpose: To analyze patterns of failure in patients with head-and-neck cutaneous squamous cell carcinoma (HNCSCC) and clinical/radiologic evidence of perineural invasion (CPNI), in order to define neural clinical target volume (CTV) for treatment planning. Methods and Materials: Patients treated with three-dimensional (3D) conformal or intensity-modulated radiotherapy (IMRT) for HNCSCC with CPNI were included in the study. A retrospective review of the clinical charts, radiotherapy (RT) plans and radiologic studies has been conducted. Results: Eleven consecutive patients with HNCSCCs with CPNI were treated from 2000 through 2007. Most patients underwent multiple surgical procedures and RT courses. The most prevalent failure pattern was along cranial nerves (CNs), and multiple CNs were ultimately involved in the majority of cases. In all cases the involved CNs at recurrence were the main nerves innervating the primary tumor sites, as well as their major communicating nerves. We have found several distinct patterns of disease spread along specific CNs depending on the skin regions harboring the primary tumors, including multiple branches of CN V and VII. These patterns and the pertinent anatomy are detailed in the this article. Conclusions: Predictable disease spread patterns along cranial nerves supplying the primary tumor sites were found in this study. Awareness of these patterns, as well as knowledge of the relevant cranial nerve anatomy, should be the basis for CTV definition and delineation for RT treatment planning.

  2. Droplet Characterization and Penetration of an Ultra-Low Volume Mosquito Adulticide Spray Targeting the Asian Tiger Mosquito, Aedes albopictus, within Urban and Suburban Environments of Northeastern USA.

    Science.gov (United States)

    Faraji, Ary; Unlu, Isik; Crepeau, Taryn; Healy, Sean; Crans, Scott; Lizarraga, Griffith; Fonseca, Dina; Gaugler, Randy

    2016-01-01

    Adult control of Aedes albopictus via ultra-low volume is difficult because this species occurs primarily in peridomestic habitats where obstacles such as buildings and vegetation can disrupt spray plumes and droplet dispersion. We determined droplet penetration and characterization of a pyrethroid adulticide applied from the ground at mid (46.77 ml/ha) and maximum (93.53 ml/ha) label rates within cryptic habitats of urban and suburban environments. Droplets were collected from all habitats, with no significant differences detected between locations within the same application rate or collection method. No differences were detected in droplet densities (drops per mm2) between rates within urban environments, but more droplets were collected in urban (149.93 ± 11.07 SE) than suburban sites (114.37 ± 11.32) at the maximum label rate (P = 0.003). The excellent penetration of aerosols into cryptic habitats of an urban site was likely due to the shorter spray paths afforded by our network of roads and alleys. Mid label rates displayed similar droplet density values as maximum label rates in urban areas, indicating that lower rates may be used effectively to reduce costs, lessen non-target effects, and increase environmental stewardship. Advances in formulations and technology are driving changes in adulticide applications, leading to use of the minimum effective dose for maximum efficacy, precision, and accountability. PMID:27116103

  3. Prospective evaluation of microscopic extension using whole-mount preparation in patients with hepatocellular carcinoma: Definition of clinical target volume for radiotherapy

    International Nuclear Information System (INIS)

    To define the clinical target volume (CTV) for radiotherapy in patients with hepatocellular carcinoma (HCC). A prospective study was conducted to histologically evaluate the presence and the distance of microscopic extension (ME) for resected HCC on the basis of examination of whole-mount preparations of carcinoma tissue sections. A total of 380 whole-mount slides prepared from tumor samples of 76 patients with HCC were examined. Patients with elevated pretreatment AFP levels exhibited higher risk of ME as compared to those with normal pretreatment AFP levels (93.9% vs. 69.8%, P < 0.01). ME positivity was 16.7% for Grade 1, 79.1% for Grade 2, and 96.3% for Grade 3 tumors (P < 0.01). The mean distance of ME was 0.0 ± 0.1 mm (range 0-0.2 mm) for Grade 1, 0.9 ± 0.9 mm (range 0-4.5 mm) for Grade 2, and 1.9 ± 1.9 mm (range 0-8.0 mm) for Grade 3 tumors (P < 0.01). The CTV margins for tumor Grades 1, 2, and 3 HCC, are recommended to be 0.2 mm, 4.5 mm, and 8.0 mm beyond the gross tumor margin, respectively, to account for possible ME of the tumors in all patients

  4. Droplet Characterization and Penetration of an Ultra-Low Volume Mosquito Adulticide Spray Targeting the Asian Tiger Mosquito, Aedes albopictus, within Urban and Suburban Environments of Northeastern USA

    Science.gov (United States)

    Faraji, Ary; Unlu, Isik; Crepeau, Taryn; Healy, Sean; Crans, Scott; Lizarraga, Griffith; Fonseca, Dina; Gaugler, Randy

    2016-01-01

    Adult control of Aedes albopictus via ultra-low volume is difficult because this species occurs primarily in peridomestic habitats where obstacles such as buildings and vegetation can disrupt spray plumes and droplet dispersion. We determined droplet penetration and characterization of a pyrethroid adulticide applied from the ground at mid (46.77 ml/ha) and maximum (93.53 ml/ha) label rates within cryptic habitats of urban and suburban environments. Droplets were collected from all habitats, with no significant differences detected between locations within the same application rate or collection method. No differences were detected in droplet densities (drops per mm2) between rates within urban environments, but more droplets were collected in urban (149.93 ± 11.07 SE) than suburban sites (114.37 ± 11.32) at the maximum label rate (P = 0.003). The excellent penetration of aerosols into cryptic habitats of an urban site was likely due to the shorter spray paths afforded by our network of roads and alleys. Mid label rates displayed similar droplet density values as maximum label rates in urban areas, indicating that lower rates may be used effectively to reduce costs, lessen non-target effects, and increase environmental stewardship. Advances in formulations and technology are driving changes in adulticide applications, leading to use of the minimum effective dose for maximum efficacy, precision, and accountability. PMID:27116103

  5. Circumferential or sectored beam arrangements for stereotactic body radiation therapy (SBRT) of primary lung tumors: Effect on target and normal-structure dose-volume metrics

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Mara W. [Broad Institute of MIT and Harvard, Cambridge, MA (United States); Department of Physics, Brandeis University, Waltham, MA (United States); Kato, Catherine M. [Macalester College, St. Paul, MN (United States); Carson, Kelly M.P. [The University of North Carolina, Chapel Hill, NC (United States); Matsunaga, Nathan M. [Santa Clara University, Santa Clara, CA (United States); Arao, Robert F. [Department of Public Health and Preventive Medicine, Oregon Health and Science University, Portland, OR (United States); Doss, Emily J. [Department of Internal Medicine, Providence St. Vincent Medical Center, Portland, OR (United States); McCracken, Charles L. [Department of Radiation Medicine, Oregon Health and Science University, Portland, OR (United States); Meng, Lu Z. [Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, CA (United States); Chen, Yiyi [Department of Public Health and Preventive Medicine, Oregon Health and Science University, Portland, OR (United States); Laub, Wolfram U.; Fuss, Martin [Department of Radiation Medicine, Oregon Health and Science University, Portland, OR (United States); Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, Corvallis, OR (United States); Tanyi, James A., E-mail: tanyij@ohsu.edu [Department of Radiation Medicine, Oregon Health and Science University, Portland, OR (United States); Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, Corvallis, OR (United States)

    2013-01-01

    To compare 2 beam arrangements, sectored (beam entry over ipsilateral hemithorax) vs circumferential (beam entry over both ipsilateral and contralateral lungs), for static-gantry intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) delivery techniques with respect to target and organs-at-risk (OAR) dose-volume metrics, as well as treatment delivery efficiency. Data from 60 consecutive patients treated using stereotactic body radiation therapy (SBRT) for primary non–small-cell lung cancer (NSCLC) formed the basis of this study. Four treatment plans were generated per data set: IMRT/VMAT plans using sectored (-s) and circumferential (-c) configurations. The prescribed dose (PD) was 60 Gy in 5 fractions to 95% of the planning target volume (PTV) (maximum PTV dose ∼ 150% PD) for a 6-MV photon beam. Plan conformality, R{sub 50} (ratio of volume circumscribed by the 50% isodose line and the PTV), and D{sub 2} {sub cm} (D{sub max} at a distance ≥2 cm beyond the PTV) were evaluated. For lungs, mean doses (mean lung dose [MLD]) and percent V{sub 30}/V{sub 20}/V{sub 10}/V{sub 5} Gy were assessed. Spinal cord and esophagus D{sub max} and D{sub 5}/D{sub 50} were computed. Chest wall (CW) D{sub max} and absolute V{sub 30}/V{sub 20}/V{sub 10}/V{sub 5} {sub Gy} were reported. Sectored SBRT planning resulted in significant decrease in contralateral MLD and V{sub 10}/V{sub 5} {sub Gy}, as well as contralateral CW D{sub max} and V{sub 10}/V{sub 5} {sub Gy} (all p < 0.001). Nominal reductions of D{sub max} and D{sub 5}/D{sub 50} for the spinal cord with sectored planning did not reach statistical significance for static-gantry IMRT, although VMAT metrics did show a statistically significant decrease (all p < 0.001). The respective measures for esophageal doses were significantly lower with sectored planning (p < 0.001). Despite comparable dose conformality, irrespective of planning configuration, R{sub 50} significantly improved with IMRT

  6. Synthesis of knowledge of the potential impacts of OCS (Outer Continental Shelf) oil and gas activities on fisheries. Volume 1. Appendix, annotated bibliography and data base descriptions for target species, distribution and abundance studies. Section 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tear, L.M.

    1989-10-01

    The purpose of the appendix is to present an annotated bibliography of published and grey literature related to the distribution and abundance of select species of finfish and shellfish along the coasts of the United States. The volume also includes descriptions of data bases that contain information related to target species distribution and abundance.

  7. How does knowledge of three-dimensional excision margins following breast conservation surgery impact upon clinical target volume definition for partial-breast radiotherapy?

    International Nuclear Information System (INIS)

    Background and purpose: To compare partial-breast clinical target volumes generated using a standard 15 mm margin (CTVstandard) with those generated using three-dimensional surgical excision margins (CTVtailored30) in women who have undergone wide local excision (WLE) for breast cancer. Material and methods: Thirty-five women underwent WLE with placement of clips in the anterior, deep and coronal excision cavity walls. Distances from tumour to each of six margins were measured microscopically. Tumour bed was defined on kV-CT images using clips. CTVstandard was generated by adding a uniform three-dimensional 15 mm margin, and CTVtailored30 was generated by adding 30 mm minus the excision margin in three-dimensions. Concordance between CTVstandard and CTVtailored30 was quantified using conformity (CoI), geographical-miss (GMI) and normal-tissue (NTI) indices. An external-beam partial-breast irradiation (PBI) plan was generated to cover 95% of CTVstandard with the 95% isodose. Percentage-volume coverage of CTVtailored30 by the 95% isodose was measured. Results: Median (range) coronal, superficial and deep excision margins were 15.0 (0.5-76.0) mm, 4.0 (0.0-60.0) mm and 4.0 (0.5-35.0) mm, respectively. Median CoI, GMI and NTI were 0.62, 0.16 and 0.20, respectively. Median coverage of CTVtailored30 by the PBI-plan was 97.7% (range 84.9-100.0%). CTVtailored30 was inadequately covered by the 95% isodose in 4/29 cases. In three cases, the excision margin in the direction of inadequate coverage was ≤2 mm. Conclusions: CTVs based on 3D excision margin data are discordant with those defined using a standard uniform 15 mm TB-CTV margin. In women with narrow excision margins, the standard TB-CTV margin could result in a geographical miss. Therefore, wider TB-CTV margins should be considered where re-excision does not occur.

  8. Potential role of proton therapy in the treatment of pediatric medulloblastoma/primitive neuroectodermal tumors: reduction of the supratentorial target volume

    International Nuclear Information System (INIS)

    Purpose: One of the components of radiotherapy (RT) in medulloblastoma/primitive neuroectodermal tumors is the prophylactic irradiation of the whole brain (WBI). With the aim of reducing late neuropsychologic morbidity a CT-scan-based dosimetric study was undertaken in which treatment was confined mainly or exclusively to supratentorial sites considered at high risk for disease recurrence. Methods and Materials: A comparative dosimetric study is presented in which a three field (two laterals and one posterior) proton plan (spot scanning method) is compared with a two-field conventional WBI 6 MV x-ray plan, to a 6-field 'hand-made' 6 MV x-ray plan, and to a computer-optimized 9-field 'inverse' 15 MV x-ray plan. For favorable patients, 30 Gy were delivered to the ventricles and main cisterns, the subfrontal and subtemporal regions, and the posterior fossa. For the unfavorable patients, 10 Gy WBI preceded a boost to 30 Gy to the same treatment volume chosen for favorable patients. The dose distribution was evaluated with dose-volume histograms to examine the coverage of the targets as well as the dose to the nontarget brain and optical structures. In addition, the risks of radiation-related late neuropsychologic effects after WBI were collected from the literature and used to predict normal tissue complication probabilities (NTCPs) for an intelligence quotient deficit after treatment with photon or proton beams. Results: Proton beams succeeded better in reducing the dose to the brain hemispheres and eye than any of the photon plans. A 25.1% risk of an IQ score <90 was predicted after 30 Gy WBI. Almost a 10% drop in the predicted risk was observed when using proton beams in both favorable and unfavorable patients. However, predicted NTCPs for both optimized photon plans ('hand made' and 'inverse') were only slightly higher (0.3-2.5%) than those of proton beams. An age-modifying factor was introduced in the predictive NTCP model to assess for IQ differences in relation

  9. Estimation of the mediastinal involvement probability in non-small cell lung cancer: a statistical definition of the clinical target volume for 3-dimensional conformal radiotherapy?

    International Nuclear Information System (INIS)

    Purpose. - Conformal irradiation of non-small cell lung carcinoma (NSCLC) is largely based on a precise definition of the nodal clinical target volume (CTVn). The reduction of the number of nodal stations to be irradiated would render tumor dose escalation more achievable. The aim of this work was to design an mathematical tool based on documented data, that would predict the risk of metastatic involvement for each nodal station. Methods and material. - From the large surgical series published in the literature we looked at the main pre-treatment parameters that modify the risk of nodal invasion. The probability of involvement for the 17 nodal stations described by the American Thoracic Society (ATS) was computed from all these publications and then weighted according to the French epidemiological data. Starting from the primitive location of the tumour as the main characteristic, we built a probabilistic tree for each nodal station representing the risk distribution as a function of each tumor feature. From the statistical point of view, we used the inversion of probability trees method described by Weinstein and Feinberg. Results. -Taking into account all the different parameters of I the pre-treatment staging relative to each level of the ATS map brings up to 20,000 different combinations. The first chosen parameters in the tree were, depending on the tumour location, the histological classification, the metastatic stage, the nodal stage weighted in function of the sensitivity and specificity of the diagnostic examination used (PET scan, CAT scan) and the tumoral stage. A software is proposed to compute a predicted probability of involvement of each nodal station for any given clinical presentation.Conclusion. -To better define the CTVn in NSCLC 3DRT, we propose a software that evaluates the mediastinal nodal involvement risk from easily accessible individual pretreatment parameters. (authors)

  10. Determination of the optimal statistical uncertainty to perform electron-beam Monte Carlo absorbed dose estimation in the target volume; Determination de l'incertitude statistique optimale pour realiser un calcul de dose dans le volume cible en utilisant la methode de Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Isambert, A.; Lefkopoulos, D. [Institut Gustave-Roussy, Medical Physics Dept., 94 - Villejuif (France); Brualla, L. [NCTeam, Strahlenklinik, Universitatsklinikum Essen (Germany); Benkebil, M. [DOSIsoft, 94 - Cachan (France)

    2010-04-15

    Purpose of study Monte Carlo based treatment planning system are known to be more accurate than analytical methods for performing absorbed dose estimation, particularly in and near heterogeneities. However, the required computation time can still be an issue. The present study focused on the determination of the optimum statistical uncertainty in order to minimise computation time while keeping the reliability of the absorbed dose estimation in treatments planned with electron-beams. Materials and methods Three radiotherapy plans (medulloblastoma, breast and gynaecological) were used to investigate the influence of the statistical uncertainty of the absorbed dose on the target volume dose-volume histograms (spinal cord, intra-mammary nodes and pelvic lymph nodes, respectively). Results The study of the dose-volume histograms showed that for statistical uncertainty levels (1 S.D.) above 2 to 3%, the standard deviation of the mean dose in the target volume calculated from the dose-volume histograms increases by at least 6%, reflecting the gradual flattening of the dose-volume histograms. Conclusions This work suggests that, in clinical context, Monte Carlo based absorbed dose estimations should be performed with a maximum statistical uncertainty of 2 to 3%. (authors)

  11. Toward optimal organ at risk sparing in complex volumetric modulated arc therapy: An exponential trade-off with target volume dose homogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Tol, Jim P., E-mail: j.tol@vumc.nl; Dahele, Max; Doornaert, Patricia; Slotman, Ben J.; Verbakel, Wilko F. A. R. [Department of Radiation Oncology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam (Netherlands)

    2014-02-15

    Purpose: Conventional radiotherapy typically aims for homogenous dose in the planning target volume (PTV) while sparing organs at risk (OAR). The authors quantified and characterized the trade-off between PTV dose inhomogeneity (IH) and OAR sparing in complex head and neck volumetric modulated arc therapy plans. Methods: Thirteen simultaneous integrated boost plans were created per patient, for ten patients. PTV boost{sub (B)}/elective{sub (E)} optimization priorities were systematically increased. IH{sub B} and IH{sub E}, defined as (100% − V95%) + V107%, were evaluated against the average of the mean dose to the combined composite swallowing and combined salivary organs (D-OAR{sub comp}). To investigate the influence of OAR size and position with respect to PTV{sub B/E}, OAR dose was evaluated against a modified Euclidean distance (DM{sub B}/DM{sub E}) between OAR and PTV. Results: Although the achievable D-OAR{sub comp} for a given level of PTV IH differed between patients, excellent logarithmic fits described the D-OAR{sub comp}/IH{sub B} and IH{sub E} relationship in all patients (mean R{sup 2} of 0.98 and 0.97, respectively). Allowing an increase in average IH{sub B} and IH{sub E} over a clinically acceptable range, e.g., from 0.4% ± 0.5% to 2.0% ± 2.0% and 6.9% ± 2.8% to 14.8% ± 2.7%, respectively, corresponded to a decrease in average dose to the composite salivary and swallowing structures from 30.3 ± 6.5 to 23.6 ± 4.7 Gy and 32.5 ± 8.3 to 26.8 ± 9.3 Gy. The increase in PTV{sub E} IH was mainly accounted for by an increase in V107, by on average 5.9%, rather than a reduction in V95, which was on average only 2%. A linear correlation was found between the OAR dose to composite swallowing structures and contralateral parotid and submandibular gland, with DM{sub E} (R{sup 2} = 0.83, 0.88, 0.95). Only mean ipsilateral parotid dose correlated with DM{sub B} (R{sup 2} = 0.87). Conclusions: OAR sparing is highly dependent on the permitted PTV{sub B

  12. Synthesis of knowledge of the potential impacts of OCS (Outer Continental Shelf) oil and gas activities on fisheries. Volume 1. Appendix, annotated bibliography and data base descriptions for target species, distribution and abundance studies. Section 1, Part 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tear, L.M.

    1989-10-01

    The purpose of the appendix is to present an annotated bibliography of published and grey literature related to the distribution and abundance of select species of finfish and shellfish along the coasts of the United States. The volume also includes descriptions of data bases that contain information related to target species distribution and abundance. An index is provided at the end of each section to help the reader locate studies or data bases related to a particular species.

  13. Synthesis of knowledge of the potential impacts of OCS (Outer Continental Shelf) oil and gas activities on fisheries. Volume 1. Appendix, annotated bibliography, and data base descriptions for target species, distribution and abundance studies. Section 1, Part 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tear, L.M.

    1989-10-01

    The purpose of the appendix is to present an annotated bibliography of published and grey literature related to the distribution and abundance of select species of finfish and shellfish along the coasts of the United States. The volume also includes descriptions of databases that contain information related to target species distribution and abundance. An index is provided at the end of each section to help the reader locate studies or data bases related to a particular species.

  14. Methodologies for localizing loco-regional hypopharyngeal carcinoma recurrences in relation to FDG-PET positive and clinical radiation therapy target volumes

    DEFF Research Database (Denmark)

    Due, Anne Kirkebjerg; Korreman, Stine Sofia; Tomé, Wolfgang;

    2010-01-01

    Focal methods to determine the source of recurrence are presented, tested for reproducibility and compared to volumetric approaches with respect to the number of recurrences ascribed to the FDG-PET positive and high dose volumes....

  15. Probe into the clinical significance of target volume and change of the normal organs in image-guided radiotherapy for nasopharynegeal carcinoma

    International Nuclear Information System (INIS)

    Objective: To study the changes in gross tumor volume (GTV) and normal organs dur- ing intensity modulated radiation therapy (IMRT), and the probability of carrying out image-guided radio- therapy(IGRT) for nasopharyngeal carcinoma. Methods: Fifteen patients with nasopharyngeal carcinoma were treated by IMRT. CT was acquired before the planning, start of treatment and at the twenty-fifth time during radiotherapy. All images were fused with the second, third CT pictures and the initial CT pictures. Both GTV and normal tissues were manually contoured on every, axial slice to investigate the changes. Results: Primary tumor volume increased in two cases after finishing plan. Up to the twenty-fifth time during radiotherapy, primary tumors and parotid glands in volume decreased by 0-10.39 cm3 (gas volume) and 0.13-23.80 cm3; The shrunken degree correlated with the volume of the parotid glands before IMRT. The axial diameters of head decreased incoordinately. Conclusions: The primary tumor and normal tissue is changed during IMRT in nasopharyngeal carcinoma. The clinical consequences of these may be underdosage of tumor volume and/or overdosage of critical normal structures. Conclusively, the study is helpful in carrying out the second IMRT plan or IGRT for nasopharyngeal carcinoma. (authors)

  16. Contribution of 18F-Fluoro-ethyl-tyrosine Positron Emission Tomography to Target Volume Delineation in Stereotactic Radiotherapy of Malignant Cranial Base Tumours: First Clinical Experience

    Directory of Open Access Journals (Sweden)

    Reinhold Graf

    2012-01-01

    Full Text Available Increased amino acid uptake has been demonstrated in intracerebral tumours and head and neck carcinomas of squamous cell origin. We investigated the potential impact of using 18F-fluoro-ethyl-tyrosine (18F-FET-PET/CT in addition to conventional imaging for gross tumour volume (GTV delineation in stereotactic radiotherapy of skull base tumours. The study population consisted of 14 consecutive patients with cranial base tumours (10 with squamous cell histology, 4 others. All patients underwent a FET-PET/CT examination in addition to contrast-enhanced CT and 11 patients underwent MRI. All tumours and histologic types showed increased FET uptake. The GTV was defined by all voxels showing hyperintensity in MRI or CT (GTVMRI/CT or enhancement in PET (GTVPET, forming a GTVcomposite that was used for the initial treatment fields. An additional volume of infiltrative growth outside the GTVMRI/CT of about 1.0 ± 2 cm3 (5% of the conventional volume was demonstrated by FET-PET only (GTVPETplus with significant enlargement (>10% of GTVMRI/CT in three patients. From existing data, we found correlation between cellular density and the standardized uptake value (SUV of FET. We were able to substantially reduce the volume of escalated radiation dose (GTVboost by 11 ± 2 cm3 (24% of the conventional volume.

  17. More Accurate Definition of Clinical Target Volume Based on the Measurement of Microscopic Extensions of the Primary Tumor Toward the Uterus Body in International Federation of Gynecology and Obstetrics Ib-IIa Squamous Cell Carcinoma of the Cervix

    International Nuclear Information System (INIS)

    Purpose: To more accurately define clinical target volume for cervical cancer radiation treatment planning by evaluating tumor microscopic extension toward the uterus body (METU) in International Federation of Gynecology and Obstetrics stage Ib-IIa squamous cell carcinoma of the cervix (SCCC). Patients and Methods: In this multicenter study, surgical resection specimens from 318 cases of stage Ib-IIa SCCC that underwent radical hysterectomy were included. Patients who had undergone preoperative chemotherapy, radiation, or both were excluded from this study. Microscopic extension of primary tumor toward the uterus body was measured. The association between other pathologic factors and METU was analyzed. Results: Microscopic extension toward the uterus body was not common, with only 12.3% of patients (39 of 318) demonstrating METU. The mean (±SD) distance of METU was 0.32 ± 1.079 mm (range, 0-10 mm). Lymphovascular space invasion was associated with METU distance and occurrence rate. A margin of 5 mm added to gross tumor would adequately cover 99.4% and 99% of the METU in the whole group and in patients with lymphovascular space invasion, respectively. Conclusion: According to our analysis of 318 SCCC specimens for METU, using a 5-mm gross tumor volume to clinical target volume margin in the direction of the uterus should be adequate for International Federation of Gynecology and Obstetrics stage Ib-IIa SCCC. Considering the discrepancy between imaging and pathologic methods in determining gross tumor volume extent, we recommend a safer 10-mm margin in the uterine direction as the standard for clinical practice when using MRI for contouring tumor volume

  18. More Accurate Definition of Clinical Target Volume Based on the Measurement of Microscopic Extensions of the Primary Tumor Toward the Uterus Body in International Federation of Gynecology and Obstetrics Ib-IIa Squamous Cell Carcinoma of the Cervix

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wen-Jia [Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong Province (China); Wu, Xiao [Department of Pathology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong Province (China); Xue, Ren-Liang; Lin, Xiang-Ying [Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong Province (China); Kidd, Elizabeth A. [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Yan, Shu-Mei [Department of Pathology, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong Province (China); Zhang, Yao-Hong [Department of Radiation Oncology, Chaozhou Hospital of Chaozhou City, Guangdong Province (China); Zhai, Tian-Tian; Lu, Jia-Yang; Wu, Li-Li; Zhang, Hao [Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong Province (China); Huang, Hai-Hua [Department of Pathology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong Province (China); Chen, Zhi-Jian; Li, De-Rui [Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong Province (China); Xie, Liang-Xi, E-mail: xieliangxi1@qq.com [Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong Province (China)

    2015-01-01

    Purpose: To more accurately define clinical target volume for cervical cancer radiation treatment planning by evaluating tumor microscopic extension toward the uterus body (METU) in International Federation of Gynecology and Obstetrics stage Ib-IIa squamous cell carcinoma of the cervix (SCCC). Patients and Methods: In this multicenter study, surgical resection specimens from 318 cases of stage Ib-IIa SCCC that underwent radical hysterectomy were included. Patients who had undergone preoperative chemotherapy, radiation, or both were excluded from this study. Microscopic extension of primary tumor toward the uterus body was measured. The association between other pathologic factors and METU was analyzed. Results: Microscopic extension toward the uterus body was not common, with only 12.3% of patients (39 of 318) demonstrating METU. The mean (±SD) distance of METU was 0.32 ± 1.079 mm (range, 0-10 mm). Lymphovascular space invasion was associated with METU distance and occurrence rate. A margin of 5 mm added to gross tumor would adequately cover 99.4% and 99% of the METU in the whole group and in patients with lymphovascular space invasion, respectively. Conclusion: According to our analysis of 318 SCCC specimens for METU, using a 5-mm gross tumor volume to clinical target volume margin in the direction of the uterus should be adequate for International Federation of Gynecology and Obstetrics stage Ib-IIa SCCC. Considering the discrepancy between imaging and pathologic methods in determining gross tumor volume extent, we recommend a safer 10-mm margin in the uterine direction as the standard for clinical practice when using MRI for contouring tumor volume.

  19. A correlation study on target displacement and volume variation of primary middle and distal esophageal cancer during normal respiration using four-dimensional CT

    International Nuclear Information System (INIS)

    Objective: To investigate the correlation between the motion of gross tumor volume (GTV) and the interested organs, and the correlation between the volume of GTV and the volume of heart and lung for the mid - and distal esophageal cancer using four - dimensional CT (4 DCT). Methods: Seventeen patients with middle/distal esophageal carcinoma underwent respiration-synchronized 4DCT simulation during free breathing. All image sets were registered with the reference image (T0 phase), and the GTV, the dome of diaphragm, lung and heart were delineated on CT images of the ten respiratory phases. The position of GTV, lung, heart and the dome of diaphragm were identified in all 4DCT phases,and the volume of GTV, lung and heart were also achieved. Paired sample t test were performed to compare the primary esophageal cancer displacement in the three directions. The pearson correlation test was use to study the correlation of GTV motion with the OARs , and the volume correlation of GTV with lung and heart.Results The maximum displacement of the GTV were 0.19 cm, 0.17 cm, and 0.48 cm, respectively in x, y and z directions. And the displacement were significant different between z and x, y directions (t = - 3. 59, - 4. 09, P = 0.002, 0.001). The displacement of GTV correlated well with right lung and heart in three dimensions (TRL-x = 0.922, PRL-x = 0.000, TRL-y = 0.700, PRL-y = 0.024, rRL-z = 0.994, PrRL-z = 0.000; TH-x = 0.720, PH-x = 0.010, rH-y = 0.920, PH-y = 0.000, rH-z = 0.910, PH-z = 0.000), and only significantly associated with left lung in z direction (r = 0.987, P = 0.000). There was a good correlation between GTV and the dome of diaphragm in z direction (rL = 0.918, PL = 0.000; rR= 0.928, PR= 0.000). Changes in the GTV volume was correlated well with the lung volume (rLL = - 0.680, PLL =0.031; rrL = - 0.670, PrL = 0.034), but the correlation was not significant with the heart (r= -0.368, P= 0.295) during respiratory cycle. Conclusions: For middle/distal esophageal

  20. Impact of the PET on the treatment decision and the target volume definition in the non at small cells lung cancer- definitive results clinical part

    International Nuclear Information System (INIS)

    The analysis was realized at 134 patient's of median age 61 years. It was in 65 % of cases a epidermoid carcinoma and 35 % of an adenocarcinoma, undifferentiated in 9% of cases and well differentiated in 29 % of the cases. The majority of tumors were of stage 3 (79 %). The Tep has led a new dosimetry for 21.6 % of the inclusive. In the end the decision of radiotherapy was cancelled for 9 patients (6.7 %). At 43 patients (34 %), the Tep has led a modification of the radiotherapy protocol. These modifications concerned the total dose ( 20 patients), the dose by session ( 5 patients), the total volume ( 34 patients), the number of beams ( 11 patients) or the number of volumes ( 10 patients). (N.C.)

  1. Costs and benefits of industrial reporting and voluntary targets for energy efficiency. A report to the Congress of the United States. Volume I: Main report

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    Section 131(c) of the Energy Policy Act of 1992 (EPACT) (Public Law 102-486) requires the Department of Energy (DOE) to evaluate the costs and benefits of federally mandated energy efficiency reporting requirements and voluntary energy efficiency improvement targets for energy-intensive industries. It also requires DOE to evaluate the role of reporting and targets in improving energy efficiency. Specifically, the legislation states: Not later than one year after the data of the enactment of this Act, the Secretary shall, in consultation with affected industries, evaluate and report to the Congress regarding the establishment of Federally mandated energy efficiency reporting requirements and voluntary energy efficiency improvement targets for energy intensive industries. Such report shall include an evaluation of the costs and benefits of such reporting requirements and voluntary energy efficiency improvement targets, and recommendations regarding the role of such activities in improving energy efficiency in energy intensive industries. This report is DOE`s response to that directive. It is the culmination of a year-long study that included (1) analysis of documents pertaining to a previous reporting and targets effort, the industrial Energy Efficiency Improvements Program (or the CE-189 program, following the designation of the reporting form used to collect data in that program), administered by DOE from 1976 to 1985, as well as other important background information; (2) extensive consultations with government and industry officials regarding the CE-189 Program, experience with other programs that have reporting elements, and the attributes of possible alternative strategies for reporting and targets; and (3) analyses of the costs and benefits of the CE-189 Program and several alternatives to the CE-189 approach.

  2. Lipiodol injections for optimization of target volume delineation in a patient with a second tumor of the oropharynx. A case report

    International Nuclear Information System (INIS)

    Lipiodol injections were administered in the head and neck area to improve gross tumor volume (GTV) definition for small-volume re-irradiation of a 63-year-old previously irradiated patient with a second tumor of the oropharynx in the posterior wall with longitudinal ligament infiltration (cT4cN0cM0). The patient had dialysis-depending renal failure. On diagnostic computed tomography (CT), which was performed with intravenous contrast agent, the tumor in the oropharynx was not detectable. Because of dialysis-depending renal failure comorbidity, no contrast agent was applied in the planning CT and in the diagnostic magnetic resonance imaging (MRI) study. In each cross-sectional imaging study performed, the GTV, especially in craniocaudal extensions, was not safely delineable. Therefore, craniocaudal tumor margins were pharyngoscopically marked with Lipiodol injections, an iodine-containing contrast agent. In a second planning CT, the GTV could be defined with the help of the Lipiodol marks and small-volume re-irradiation was performed. No Lipiodol-associated side effects occurred in the patient. In the present case, the use of Lipiodol injections at the tumor margins facilitated the definition of the GTV. (orig.)

  3. Costs and benefits of industrial reporting and voluntary targets for energy efficiency. A report to the Congress of the United States. Volume II: Appendices

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    This part sets forth the regulations for the Industrial Energy conservation Program established under Part E of Title III of the Act. It includes criteria and procedures for the identification of reporting corporations, reporting requirements, criteria and procedures for exemption from filing reports directly with DOE, voluntary industrial energy efficiency improvement targets and voluntary recovered materials utilization targets. The purpose of the program is to promote increased energy conservation by American industry and, as it relates to the use of recovered materials, to conserve valuable energy and scarce natural resources.

  4. 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography-Based Radiotherapy Target Volume Definition in Non-Small-Cell Lung Cancer: Delineation by Radiation Oncologists vs. Joint Outlining With a PET Radiologist?

    International Nuclear Information System (INIS)

    Purpose: 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) has benefits in target volume (TV) definition in radiotherapy treatment planning (RTP) for non-small-cell lung cancer (NSCLC); however, an optimal protocol for TV delineation has not been determined. We investigate volumetric and positional variation in gross tumor volume (GTV) delineation using a planning PET/CT among three radiation oncologists and a PET radiologist. Methods and Materials: RTP PET/CT scans were performed on 28 NSCLC patients (Stage IA-IIIB) of which 14 patients received prior induction chemotherapy. Three radiation oncologists and one PET radiologist working with a fourth radiation oncologist independently delineated the GTV on CT alone (GTVCT) and on fused PET/CT images (GTVPETCT). The mean percentage volume change (PVC) between GTVCT and GTVPETCT for the radiation oncologists and the PVC between GTVCT and GTVPETCT for the PET radiologist were compared using the Wilcoxon signed-rank test. Concordance index (CI) was used to assess both positional and volume change between GTVCT and GTVPETCT in a single measurement. Results: For all patients, a significant difference in PVC from GTVCT to GTVPETCT exists between the radiation oncologist (median, 5.9%), and the PET radiologist (median, -0.4%, p = 0.001). However, no significant difference in median concordance index (comparing GTVCT and GTVFUSED for individual cases) was observed (PET radiologist = 0.73; radiation oncologists = 0.66; p = 0.088). Conclusions: Percentage volume changes from GTVCT to GTVPETCT were lower for the PET radiologist than for the radiation oncologists, suggesting a lower impact of PET/CT in TV delineation for the PET radiologist than for the oncologists. Guidelines are needed to standardize the use of PET/CT for TV delineation in RTP.

  5. Study for identification of beneficial Uses of Space (BUS). Volume 2: Technical report. Book 3: Development and business analysis of space processed tungsten fox X-ray targets

    Science.gov (United States)

    1975-01-01

    The development plans, analysis of required R and D and production resources, the costs of such resources, and finally, the potential profitability of a commercial space processing opportunity for containerless melting and resolidification of tungsten are discussed. The aim is to obtain a form of tungsten which, when fabricated into targets for X-ray tubes, provides at least, a 50 percent increase in service life.

  6. MRI-assisted versus conventional treatment planning in brachytherapy of cervical and endometrial carcinoma: The impact of individual anatomy on dose distribution in target volume and organs at risk

    International Nuclear Information System (INIS)

    Objective: Dose prescription and definition of target volume in brachytherapy of cervical and endometrial cancer are calculated to standard points as Manchester point A or point My(ometrium) in most centers. Calculation of doses to organs at risk mainly relies on ICRU-report 38. But standard dose prescription neglects individual patient anatomy. While MRI and CT had widespread impact on individual planning in external beam radiotherapy, there is still a minor influence on brachytherapy. The impact of individual anatomy on dose distribution in target volume and organs at risk demonstrates the objective of individual brachytherapy planning. Materials and Methods: 8 patients with cervical and 4 patients with endometrial carcinoma underwent MRI of the pelvis with in-situ applicators (ring-tandem applicators for cervical carcinoma and modified Heyman-capsules for endometrial carcinoma). T1w slices were angulated coronal and sagittal to get rectangular reproductions to applicator axis. Orthogonal or isocentric X-ray films for conventional treatment planning were done. MRI-information on target and organs at risk was transformed into coordinates relative to applicator axis and dose calculation on the database of conventional treatment planning was performed by Nucletron Planning System PLATO. Isodoses were projected into MRI slices. Prescribed dose to patients with cervical cancer was 8.5 Gy to point A resp. 10 Gy to point My (2cm below fundal myometrium and 2cm lateral applicator axis) in endometrial cancer. Results: Dose prescription to Manchester point A or point My represented in only 50% of cases uterine serosa. Instead of 2cm lateral of applicator axis, uterine surface ranged from 1.0 cm to 3.9 cm at the level of point A (mean 2.25 cm coronal and 1.77 cm sagittal) and from 1.5 cm to 4.4 cm at the level of point My (mean 2.7 cm coronal and 2.1 cm sagittal). Uterine volume ranged from 69 cc to 277 cc, mean volume was 150cc. Dose-volume histograms of patients with

  7. Differences in the definition of internal target volumes using slow CT alone or in combination with thin-slice CT under breath-holding conditions during the planning of stereotactic radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Purpose: To investigate how the delineations of the internal target volume (ITV) made from 'slow' CT alter with reference to 'thin-slice' CT. Materials and methods: Thin-slice CT images taken under breath-holding conditions and slow CT images taken under shallow-breathing conditions (8 s/image) of 11 lung cancers were used for this study. Five radiation oncologists delineated ITV of the 11 lesions using slow CT images (ITV1), and then redefined them with reference to thin-slice CT images (ITV2). SD-images (standard deviation image) were created for all patients from ITV images in order to visualize the regional variation of the ITVs. Results: The mean value of ITV2 was smaller than that initially defined by ITV1. There was no significant change in ITV1 and ITV2 between operators with regard to standard deviation in volume. There was a significant difference in the distribution of the ratio of ITV1 to ITV2 obtained on thin-slice CTs between cases with and without ground glass opacity. In cases without ground glass opacity there was a tendency for ITV2 to have a smaller volume than ITV1. Conclusions: Combined use of slow CT and thin-slice CT in delineation of ITV contours appeared to be useful in making adjustments for obscured tumor images caused by respiratory movement

  8. Lipiodol injections for optimization of target volume delineation in a patient with a second tumor of the oropharynx. A case report

    Energy Technology Data Exchange (ETDEWEB)

    Haderlein, Marlen; Merten, Ricarda; Stojanovic, Andrea; Speer, Stefan; Fietkau, Rainer; Ott, Oliver J. [University Hospitals of Erlangen, Department of Radiation Oncology, Erlangen (Germany); Scherl, Claudia [University Hospitals of Erlangen, Department of Otorhinolaryngology, Erlangen (Germany)

    2015-08-15

    Lipiodol injections were administered in the head and neck area to improve gross tumor volume (GTV) definition for small-volume re-irradiation of a 63-year-old previously irradiated patient with a second tumor of the oropharynx in the posterior wall with longitudinal ligament infiltration (cT4cN0cM0). The patient had dialysis-depending renal failure. On diagnostic computed tomography (CT), which was performed with intravenous contrast agent, the tumor in the oropharynx was not detectable. Because of dialysis-depending renal failure comorbidity, no contrast agent was applied in the planning CT and in the diagnostic magnetic resonance imaging (MRI) study. In each cross-sectional imaging study performed, the GTV, especially in craniocaudal extensions, was not safely delineable. Therefore, craniocaudal tumor margins were pharyngoscopically marked with Lipiodol injections, an iodine-containing contrast agent. In a second planning CT, the GTV could be defined with the help of the Lipiodol marks and small-volume re-irradiation was performed. No Lipiodol-associated side effects occurred in the patient. In the present case, the use of Lipiodol injections at the tumor margins facilitated the definition of the GTV. (orig.) [German] Anwendung von Lipiodolinjektionen im Kopf-Hals-Bereich zur Verbesserung der GTV-Definition bei einer kleinvolumigen Re-Bestrahlung eines 63-jaehrigen, vorbestrahlten Patienten mit einem Zweitmalignom im Oropharynx mit Infiltration des hinteren Laengsbandes (cT4cN0cM0). Nebenbefundlich bestand bei dem Patienten eine dialysepflichtige Niereninsuffizienz. Im initialen diagnostischen Kontrastmittel-CT der Hals und Thoraxregion war der Tumor nicht abgrenzbar, so dass das Bestrahlungsplanungs-CT in Anbetracht des diagnostischen CTs und der bekannten Niereninsuffizienz ohne intravenoeses Kontrastmittel durchgefuehrt wurde. Das diagnostische MRT (vgl. Abb. 1) wurde ebenfalls ohne intravenoeses Kontrastmittel durchgefuehrt wurden. In allen durchgefuehrten

  9. Repeated CT scan in improving the reproducibility of grass tumor volume for moving target%重复CT扫描提高运动靶区勾画范围准确性研究

    Institute of Scientific and Technical Information of China (English)

    姜庆丰; 李光俊; 徐庆丰; 蒋晓芹; 柏森

    2010-01-01

    目的 通过运动靶区的模拟,探讨CT扫描对运动肿瘤靶区勾画范围准确性的影响,寻找提高运动靶区准确显示的方法.方法 以不同频率和振幅做简谐运动的靶区在CT机上扫描,每组分别重复扫描24次,然后对组内24次扫描图像每2、3次扫描随机分组融合.在Pinnacle计划系统中勾画靶区,分析运动对靶区沿运动方向长度的影响.结果 随运动幅度增加,CT扫描所得球形靶区最大体积与方形靶区最大长度都增加,球形靶区最小体积与方形靶区最小长度减小.运动频率对靶体积及长度影响较运动幅度小.对静止扫描长度为3.3 cm、运动频率为20和幅度为2 cm的方形运动靶区24次扫描中最大长度5.1 cm是最小长度2.1 cm的2.4倍.对组内24次扫描图像每1、2、3次融合,融合后靶区长度平均值±标准差分别为(3.77±1.20)、(4.18±0.91)、(4.52±0.59)cm.结论 随运动频率和幅度增加,CT扫描图像与靶区整个运动范围偏差增大.随扫描次数增加,融合所得靶区长度逐渐增加.在没有条件采取措施控制靶区运动情况下,重复CT扫描能简便有效地提高运动靶区勾画范围准确性.%Objective To find a method to improve the range accuracy of moving target such as peripheral lung tumors, since a single CT snapshot may not be accurate during the treatment process.Methods A simple harmonic motion phantom, embedded with a cube and a circular ball, was used to simulate the tumor motion. Individualized moving targets were scanned 24 times with different amplitudes and frequencies. Then the images were fused from every 1, 2 or 3 sets of CT scans. The GTV volume variation of circular target and the length variation of the cube target along the z axis were contoured and analyzed. Results As motion amplitude increased, the maximum of both circular target volume and cube target length was increased, while the minimum of the factors was decreased. Motion frequency affected the

  10. Comparative evaluation of CT-based and respiratory-gated PET/CT-based planning target volume (PTV) in the definition of radiation treatment planning in lung cancer: preliminary results

    International Nuclear Information System (INIS)

    The aim of this study was to compare planning target volume (PTV) defined on respiratory-gated positron emission tomography (PET)/CT (RG-PET/CT) to PTV based on ungated free-breathing CT and to evaluate if RG-PET/CT can be useful to personalize PTV by tailoring the target volume to the lesion motion in lung cancer patients. Thirteen lung cancer patients (six men, mean age 70.0 years, 1 small cell lung cancer, 12 non-small cell lung cancer) who were candidates for radiation therapy were prospectively enrolled and submitted to RG-PET/CT. Ungated free-breathing CT images obtained during a PET/CT study were visually contoured by the radiation oncologist to define standard clinical target volumes (CTV1). Standard PTV (PTV1) resulted from CTV1 with the addition of 1-cm expansion of margins in all directions. RG-PET/CT images were contoured by the nuclear medicine physician and radiation oncologist according to a standardized institutional protocol for contouring gated images. Each CT and PET image of the patient's respiratory cycle phases was contoured to obtain the RG-CT-based CTV (CTV2) and the RG-PET/CT-based CTV (CTV3), respectively. RG-CT-based and RG-PET/CT-based PTV (PTV2 and PTV3, respectively) were then derived from gated CTVs with a margin expansion of 7-8 mm in head to feet direction and 5 mm in anterior to posterior and left to right direction. The portions of gated PTV2 and PTV3 geometrically not encompassed in PTV1 (PTV2 out PTV1 and PTV3 out PTV1) were also calculated. Mean ± SD CTV1, CTV2 and CTV3 were 30.5 ± 33.2, 43.1 ± 43.2 and 44.8 ± 45.2 ml, respectively. CTV1 was significantly smaller than CTV2 and CTV3 (p = 0.017 and 0.009 with Student's t test, respectively). No significant difference was found between CTV2 and CTV3. Mean ± SD of PTV1, PTV2 and PTV3 were 118.7 ± 94.1, 93.8 ± 80.2 and 97.0 ± 83.9 ml, respectively. PTV1 was significantly larger than PTV2 and PTV3 (p = 0.038 and 0.043 with Student's t test, respectively). No significant

  11. Comparative evaluation of CT-based and respiratory-gated PET/CT-based planning target volume (PTV) in the definition of radiation treatment planning in lung cancer: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, Luca; Elisei, Federica [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); Meregalli, Sofia; Niespolo, Rita [San Gerardo Hospital, Radiotherapy, Monza (Italy); Zorz, Alessandra; De Ponti, Elena; Morzenti, Sabrina; Crespi, Andrea [San Gerardo Hospital, Medical Physics, Monza (Italy); Brenna, Sarah [University of Milan-Bicocca, School of Radiation Oncology, Monza (Italy); Gardani, Gianstefano [San Gerardo Hospital, Radiotherapy, Monza (Italy); University of Milan-Bicocca, Milan (Italy); Messa, Cristina [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); University of Milan-Bicocca, Tecnomed Foundation, Milan (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy)

    2014-04-15

    The aim of this study was to compare planning target volume (PTV) defined on respiratory-gated positron emission tomography (PET)/CT (RG-PET/CT) to PTV based on ungated free-breathing CT and to evaluate if RG-PET/CT can be useful to personalize PTV by tailoring the target volume to the lesion motion in lung cancer patients. Thirteen lung cancer patients (six men, mean age 70.0 years, 1 small cell lung cancer, 12 non-small cell lung cancer) who were candidates for radiation therapy were prospectively enrolled and submitted to RG-PET/CT. Ungated free-breathing CT images obtained during a PET/CT study were visually contoured by the radiation oncologist to define standard clinical target volumes (CTV1). Standard PTV (PTV1) resulted from CTV1 with the addition of 1-cm expansion of margins in all directions. RG-PET/CT images were contoured by the nuclear medicine physician and radiation oncologist according to a standardized institutional protocol for contouring gated images. Each CT and PET image of the patient's respiratory cycle phases was contoured to obtain the RG-CT-based CTV (CTV2) and the RG-PET/CT-based CTV (CTV3), respectively. RG-CT-based and RG-PET/CT-based PTV (PTV2 and PTV3, respectively) were then derived from gated CTVs with a margin expansion of 7-8 mm in head to feet direction and 5 mm in anterior to posterior and left to right direction. The portions of gated PTV2 and PTV3 geometrically not encompassed in PTV1 (PTV2 out PTV1 and PTV3 out PTV1) were also calculated. Mean ± SD CTV1, CTV2 and CTV3 were 30.5 ± 33.2, 43.1 ± 43.2 and 44.8 ± 45.2 ml, respectively. CTV1 was significantly smaller than CTV2 and CTV3 (p = 0.017 and 0.009 with Student's t test, respectively). No significant difference was found between CTV2 and CTV3. Mean ± SD of PTV1, PTV2 and PTV3 were 118.7 ± 94.1, 93.8 ± 80.2 and 97.0 ± 83.9 ml, respectively. PTV1 was significantly larger than PTV2 and PTV3 (p = 0.038 and 0.043 with Student's t test, respectively). No

  12. Geometrical differences in gross target volumes between 3DCT and 4DCT imaging in radiotherapy for non-small-cell lung cancer

    International Nuclear Information System (INIS)

    The aim of this study was to explore the characteristic of 3DCT scanning phases and estimate the comparative amount of respiration motion information included in 3DCT and 4DCT by comparing the volumetric and positional difference between the volumes from 3DCT and 4DCT for the radiotherapy of non-small-cell lung cancer (NSCLC). A total of 28 patients with NSCLC sequentially underwent 3DCT and 4DCT simulation scans of the thorax during free breathing. The 4DCT images with respiratory signal data were reconstructed and sorted into 10 phases throughout a respiratory cycle. GTV-3D from 3DCT, GTV-0%, GTV-20%, GTV-50% and GTV-70% from end-inspiration, mid-expiration, end-expiration and mid-inspiration of 4DCT, and the internal GTV (IGTV-10) from the fused phase of 4DCT were delineated based on the 50% phase image, respectively. The differences in the position, size, matching index (MI) and degree of inclusion (DI) for different volumes were evaluated. The variation in the centroid shifts of GTV-0% and GTV-3D, GTV-20% and GTV-3D, GTV-50% and GTV-3D, and GTV-90% and GTV-3D in the 3D direction was not significant (P = 0.990). The size ratios of GTV-0%, GTV-20%, GTV-50%, GTV-70% and IGTV-10 to GTV-3D were 0.94 ± 0.18, 0.95 ± 0.18, 0.98 ± 0.15, 1.00 ± 0.18 and 1.60 ± 0.55, respectively. DIs of GTV-3D in IGTV-10, and IGTV-10 in GTV-3D were 0.88 ± 0.14 and 0.59 ± 0.16 (P < 0.001). The 3DCT scanning phases are irregular. The CTV-to-ITV expansion should be isotropic when defining the ITV on the 3DCT. The internal GTV derived from 4DCT cannot completely include the GTV from 3DCT. An additional margin may be required when defining the ITV-based 4DCT

  13. Volume Entropy

    OpenAIRE

    Astuti, Valerio; Christodoulou, Marios; Rovelli, Carlo

    2016-01-01

    Building on a technical result by Brunnemann and Rideout on the spectrum of the Volume operator in Loop Quantum Gravity, we show that the dimension of the space of the quadrivalent states --with finite-volume individual nodes-- describing a region with total volume smaller than $V$, has \\emph{finite} dimension, bounded by $V \\log V$. This allows us to introduce the notion of "volume entropy": the von Neumann entropy associated to the measurement of volume.

  14. Prospective evaluation of early treatment outcome in patients with meningiomas treated with particle therapy based on target volume definition with MRI and {sup 68}Ga-DOTATOC-PET

    Energy Technology Data Exchange (ETDEWEB)

    Combs, Stephanie E.; Welzel, Thomas; Habermehl, Daniel; Rieken, Stefan; Dittmar, Jan-Oliver; Kessel, Kerstin; Debus, Juergen [Univ. Hospital of Heidelberg, Dept. of Radiation Oncology, Heidelberg (Germany)], e-mail: Stephanie.Combs@med.uni-heidelberg.de; Jaekel, Oliver [Heidelberg Ion Therapy Center (HIT), Heidelberg (Germany); Haberkorn, Uwe [Univ. Hospital of Heidelberg, Dept. of Nuclear Medicine, Heidelberg (Germany)

    2013-04-15

    Purpose: To evaluate early treatment results and toxicity in patients with meningiomas treated with particle therapy. Material and methods: Seventy patients with meningiomas were treated with protons (n = 38) or carbon ion radiotherapy (n = 26). Median age was 49 years. Median age at treatment was 55 years, 24 were male (34%), and 46 were female (66%). Histology was benign meningioma in 26 patients (37%), atypical in 23 patients (33%) and anaplastic in four patients (6%). In 17 patients (24%) with skull base meningiomas diagnosis was based on the typical appearance of a meningioma. For benign meningiomas, total doses of 52.2-57.6 GyE were applied with protons. For high-grade lesions, the boost volume was 18 GyE carbon ions, with a median dose of 50 GyE applied as highly conformal radiation therapy. Nineteen patients were treated as re-irradiation. Treatment planning with MRI and 68-Ga-DOTATOC-PET was evaluated. Results: Very low rates of side effects developed, including headaches, nausea and dizziness. No severe treatment-related toxicity was observed. Local control for benign meningiomas was 100%. Five of 27 patients (19%) developed tumor recurrence during follow-up. Of these, four patients had been treated as re-irradiation for recurrent high-risk meningiomas. Actuarial local control after re-irradiation of high-risk meningiomas was therefore 67% at six and 12 months. In patients treated with primary radiotherapy, only one of 13 patients (8%) developed tumor recurrence 17 months after radiation therapy (photon and carbon ion boost). Conclusion: Continuous prospective follow-up and development of novel study concepts are required to fully exploit the long-term clinical data after particle therapy for meningiomas. To date, it may be concluded that when proton therapy is available, meningioma patients can be offered a treatment at least comparable to high-end photon therapy.

  15. 胶质母细胞瘤放射治疗靶区设计现状与思考%Target volume delineation for glioblastoma multiforme: current practice and advice

    Institute of Scientific and Technical Information of China (English)

    李明焕; 孔莉; 于金明

    2013-01-01

    胶质母细胞瘤(GBM)术后放疗大都采用MRI与CT融合影像来勾画靶区,但是否包含瘤周水肿区尚有争议.根据术后、放疗后的复发范围,不论靶区设计是否包含水肿区,大部分复发都发生在磁共振(MRI)显示增强原发肿瘤灶外2 cm之内,瘤周水肿程度与复发模式无必然关系.GBM的临床和病理特征对放化疗疗效预测和预后也有重要指导意义.GBM的靶区设计趋向于个体化,可在保证疗效的同时减少治疗毒性.%The use of adjuvant extemal-beam RT is well established in the postoperative treatment of glioblastoma multiforme (CBM).It is consensus that target volume should be determined based on the fusion images of MRI and CT,but the inclusion of peritumoural edematous is controversial.The vast majority of recurrences occur within 2 cm of the original tumor site or " in radiation field".There is no inevitable relation between the degree of peritumoral edema and recurrence model.The clinical and pathological characteristics may be as predictive and prognostic factors for the treatment of GBM.Target volume delineation for CBM tend to individual,which can maintain known outcomes and reduce treatment toxicity.

  16. Large planning target volume in whole abdomen radiation therapy in ovarian cancers - a comparison between volumetric arc and fixed beam based intensity modulation in ovarian cancers: a comparison between volumetric arc and fixed beam based intensity modulation

    International Nuclear Information System (INIS)

    Aim of this study is to assess dosimetric characteristics of multiple iso-centre volumetric-modulated arc therapy for the treatment of a large PTV in whole abdomen and ovarian cancers and in comparison with IMRT. Two patients with Epithelial Ovarian Cancer (EOC) underwent CT-simulation in supine position with vacuum cushion and acquired CT-image with 3 mm slice thickness. IMRT and VMAT plans were generated with multiple isocenter using Eclipse Planning System (V10.0.39) for (6 MV photon) Varian UNIQUE Performance Linac equipped with a Millennium-120 MLC and optimised with Progressive Resolution optimizer (PRO3) for prescription 36 Gy to the whole abdomen (PTVWAR) and 45 Gy with daily fraction of 1.8 Gy to the pelvis and pelvic nodes (PTVPelvis) with Simultaneous Integrated Boost and calculated with AAA algorithm in 2.5 mm grid resolution. Mean, V95%, V90%, V107% and uniformity number (Uniformity was defined as US-95%=D5%-D95%/Dmean) was calculated for Planning Target Volumes (PTVs). Organs at Risk (OAR's) were analysed statistically in terms of dose and volume. MU and delivery time were compared. Pre-treatment quality assurance was scored with Gamma Agreement Index (GAl) with 3% and 3 mm thresholds with EPID as well as corresponding Dynalog files were generated and analysed. Feasibility and deliverability of VMAT plans showed to be a solution for the treatment planning and delivery for a large PTV volume (PTV-WAR) treatments, surrounded by critical structures such as liver, spinal canal, and kidneys, offering good dosimetric features with significant logistic improvements compared to IMRT. VMAT combines the advantages of faster delivery and lower number of monitor units (MU). It would help to reduce potential risk of secondary malignancy. VMAT(RapidArc) showed to be a solution to WAR treatments offering good dosimetric features with significant logistic improvements compared to IMRT

  17. Volumetric-modulated arc therapy for left-sided breast cancer and all regional nodes improves target volumes coverage and reduces treatment time and doses to the heart and left coronary artery, compared with a field-in-field technique

    International Nuclear Information System (INIS)

    We compared two intensity-modulated radiotherapy techniques for left-sided breast treatment, involving lymph node irradiation including the internal mammary chain. Inverse planned arc-therapy (VMAT) was compared with a forward-planned multi-segment technique with a mono-isocenter (MONOISO). Ten files were planned per technique, delivering a 50-Gy dose to the breast and 46.95 Gy to nodes, within 25 fractions. Comparative endpoints were planning target volume (PTV) coverage, dose to surrounding structures, and treatment delivery time. PTV coverage, homogeneity and conformality were better for two arc VMAT plans; V95%PTV-T was 96% for VMAT vs 89.2% for MONOISO. Homogeneity index (HI)PTV-T was 0.1 and HIPTV-N was 0.1 for VMAT vs 0.6 and 0.5 for MONOISO. Treatment delivery time was reduced by a factor of two using VMAT relative to MONOISO (84 s vs 180 s). High doses to organs at risk were reduced (V30left lung = 14% using VMAT vs 24.4% with MONOISO; dose to 2% of the volume (D2%)heart = 26.1 Gy vs 32 Gy), especially to the left coronary artery (LCA) (D2%LCA = 34.4 Gy vs 40.3 Gy). However, VMAT delivered low doses to a larger volume, including contralateral organs (mean dose [Dmean]right lung = 4 Gy and Dmeanright breast = 3.2 Gy). These were better protected using MONOISO plans (Dmeanright lung = 0.8 Gy and Dmeanright breast = 0.4 Gy). VMAT improved PTV coverage and dose homogeneity, but clinical benefits remain unclear. Decreased dose exposure to the LCA may be clinically relevant. VMAT could be used for complex treatments that are difficult with conventional techniques. Patient age should be considered because of uncertainties concerning secondary malignancies. (author)

  18. Clinical Validation of Atlas-Based Auto-Segmentation of Multiple Target Volumes and Normal Tissue (Swallowing/Mastication) Structures in the Head and Neck

    International Nuclear Information System (INIS)

    . Conclusion: Multiple-subject ABAS of computed tomography images proved to be a useful novel tool in the rapid delineation of target and normal tissues. Although editing of the autocontours is inevitable, a substantial time reduction was achieved using editing, instead of manual contouring (180 vs. 66 min).

  19. Clinical Validation of Atlas-Based Auto-Segmentation of Multiple Target Volumes and Normal Tissue (Swallowing/Mastication) Structures in the Head and Neck

    Energy Technology Data Exchange (ETDEWEB)

    Teguh, David N. [Department of Radiation Oncology, Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Levendag, Peter C., E-mail: p.levendag@erasmusmc.nl [Department of Radiation Oncology, Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Voet, Peter W.J.; Al-Mamgani, Abrahim [Department of Radiation Oncology, Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Han Xiao; Wolf, Theresa K.; Hibbard, Lyndon S. [Elekta-CMS Software, Maryland Heights, MO 63043 (United States); Nowak, Peter; Akhiat, Hafid; Dirkx, Maarten L.P.; Heijmen, Ben J.M.; Hoogeman, Mischa S. [Department of Radiation Oncology, Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam (Netherlands)

    2011-11-15

    . Conclusion: Multiple-subject ABAS of computed tomography images proved to be a useful novel tool in the rapid delineation of target and normal tissues. Although editing of the autocontours is inevitable, a substantial time reduction was achieved using editing, instead of manual contouring (180 vs. 66 min).

  20. Proteomic and transcriptomic analysis of heart failure due to volume overload in a rat aorto-caval fistula model provides support for new potential therapeutic targets - monoamine oxidase A and transglutaminase 2

    Directory of Open Access Journals (Sweden)

    Petrak Jiri

    2011-11-01

    Full Text Available Abstract Background Chronic hemodynamic overloading leads to heart failure (HF due to incompletely understood mechanisms. To gain deeper insight into the molecular pathophysiology of volume overload-induced HF and to identify potential markers and targets for novel therapies, we performed proteomic and mRNA expression analysis comparing myocardium from Wistar rats with HF induced by a chronic aorto-caval fistula (ACF and sham-operated rats harvested at the advanced, decompensated stage of HF. Methods We analyzed control and failing myocardium employing iTRAQ labeling, two-dimensional peptide separation combining peptide IEF and nano-HPLC with MALDI-MS/MS. For the transcriptomic analysis we employed Illumina RatRef-12v1 Expression BeadChip. Results In the proteomic analysis we identified 2030 myocardial proteins, of which 66 proteins were differentially expressed. The mRNA expression analysis identified 851 differentially expressed mRNAs. Conclusions The differentially expressed proteins confirm a switch in the substrate preference from fatty acids to other sources in the failing heart. Failing hearts showed downregulation of the major calcium transporters SERCA2 and ryanodine receptor 2 and altered expression of creatine kinases. Decreased expression of two NADPH producing proteins suggests a decreased redox reserve. Overexpression of annexins supports their possible potential as HF biomarkers. Most importantly, among the most up-regulated proteins in ACF hearts were monoamine oxidase A and transglutaminase 2 that are both potential attractive targets of low molecular weight inhibitors in future HF therapy.

  1. High-risk clinical target volume delineation in CT-guided cervical cancer brachytherapy - Impact of information from FIGO stage with or without systematic inclusion of 3D documentation of clinical gynecological examination

    Energy Technology Data Exchange (ETDEWEB)

    Hegazy, Neamat [Dept. of Radiotherapy, Comprehensive Cancer Centre Vienna, Medical Univ. of Vienna, Vienna (Austria); Dept. of Clinical Oncology, Medical Univ. of Alexandria, Alexandria (Egypt); Poetter Rickard; Kirisits, Christian [Dept. of Radiotherapy, Comprehensive Cancer Centre Vienna, Medical Univ. of Vienna, Vienna (Austria); Christian Doppler Lab. for Medical Radiation Research for Radiation Oncology, Medical Univ. Vienna (Austria); Berger, Daniel; Federico, Mario; Sturdza, Alina; Nesvacil, Nicole [Dept. of Radiotherapy, Comprehensive Cancer Centre Vienna, Medical Univ. of Vienna, Vienna (Austria)], e-mail: nicole.nesvacil@meduniwien.ac.at

    2013-10-15

    Purpose: The aim of the study was to improve computed tomography (CT)-based high-risk clinical target volume (HR CTV) delineation protocols for cervix cancer patients, in settings without any access to magnetic resonance imaging (MRI) at the time of brachytherapy. Therefore the value of a systematic integration of comprehensive three-dimensional (3D) documentation of repetitive gynecological examination for CT-based HR CTV delineation protocols, in addition to information from FIGO staging, was investigated. In addition to a comparison between reference MRI contours and two different CT-based contouring methods (using complementary information from FIGO staging with or without additional 3D clinical drawings), the use of standardized uterine heights was also investigated. Material and methods: Thirty-five cervix cancer patients with CT- and MR-images and 3D clinical drawings at time of diagnosis and brachytherapy were included. HR CTV{sub stage} was based on CT information and FIGO stage. HR CTV{sub stage} {sub +3Dclin} was contoured on CT using FIGO stage and 3D clinical drawing. Standardized HR CTV heights were: 1/1, 2/3 and 1/2 of uterine height. MRI-based HR CTV was delineated independently. Resulting widths, thicknesses, heights, and volumes of HR CTV{sub stage}, HR CTV{sub stage+3Dclin} and MRI-based HR CTV contours were compared. Results: The overall normalized volume ratios (mean{+-}SD of CT/MRI{sub ref} volume) of HR CTV{sub stage} and HR{sub stage+3Dclin} were 2.6 ({+-}0.6) and 2.1 ({+-}0.4) for 1/1 and 2.3 ({+-}0.5) and 1.8 ({+-}0.4), for 2/3, and 1.9 ({+-}0.5) and 1.5 ({+-}0.3), for 1/2 of uterine height. The mean normalized widths were 1.5{+-}0.2 and 1.2{+-}0.2 for HR CTV{sub stage} and HR CTV{sub stage+3Dclin}, respectively (p < 0.05). The mean normalized heights for HR CTV{sub stage} and HR CTV{sub stage+3Dclin} were both 1.7{+-}0.4 for 1/1 (p < 0.05.), 1.3{+-}0.3 for 2/3 (p < 0.05) and 1.1{+-}0.3 for 1/2 of uterine height. Conclusion: CT-based HR

  2. Time-Adjusted Internal Target Volume: A Novel Approach Focusing on Heterogeneity of Tumor Motion Based on 4-Dimensional Computed Tomography Imaging for Radiation Therapy Planning of Lung Cancer

    International Nuclear Information System (INIS)

    Purpose: To consider nonuniform tumor motion within the internal target volume (ITV) by defining time-adjusted ITV (TTV), a volume designed to include heterogeneity of tumor existence on the basis of 4-dimensional computed tomography (4D-CT). Methods and Materials: We evaluated 30 lung cancer patients. Breath-hold CT (BH-CT) and free-breathing 4D-CT scans were acquired for each patient. The tumors were manually delineated using a lung CT window setting (window, 1600 HU; level, −300 HU). Tumor in BH-CT images was defined as gross tumor volume (GTV), and the sum of tumors in 4D-CT images was defined as ITV-4D. The TTV images were generated from the 4D-CT datasets, and the tumor existence probability within ITV-4D was calculated. We calculated the TTV80 value, which is the percentage of the volume with a tumor existence probability that exceeded 80% on ITV-4D. Several factors that affected the TTV80 value, such as the ITV-4D/GTV ratio or tumor centroid deviation, were evaluated. Results: Time-adjusted ITV images were acquired for all patients, and tumor respiratory motion heterogeneity was visualized. The median (range) ITV-4D/GTV ratio and median tumor centroid deviation were 1.6 (1.0-4.1) and 6.3 mm (0.1-30.3 mm), respectively. The median TTV80 value was 43.3% (2.9-98.7%). Strong correlations were observed between the TTV80 value and the ITV-4D/GTV ratio (R=−0.71) and tumor centroid deviation (R=−0.72). The TTV images revealed the tumor motion pattern features within ITV. Conclusions: The TTV images reflected nonuniform tumor motion, and they revealed the tumor motion pattern features, suggesting that the TTV concept may facilitate various aspects of radiation therapy planning of lung cancer while incorporating respiratory motion in the future

  3. Deuterium high pressure target

    International Nuclear Information System (INIS)

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system

  4. Deuterium High Pressure Target

    CERN Document Server

    Perevozchikov, V; Vinogradov, Yu I; Vikharev, M D; Ganchuk, N S; Golubkov, A N; Grishenchkin, S K; Demin, A M; Demin, D L; Zinov, V G; Kononenko, A A; Lobanov, V N; Malkov, I L; Yukhimchuk, S A

    2001-01-01

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm^3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system.

  5. Volume-to-volume registration

    OpenAIRE

    Harg, Erik

    2005-01-01

    Implementation of automated volume-to-volume registration applications for three separate registration steps desired in enhancing neurosurgical navigation is considered. Prototype implementations for MRI-to-MRI registration, MRI-to-US registration and US-to-US registration have been made using registration methods available in the Insight Toolkit, with variants of the Mutual Information similarity metric. The obtained results indicate that automatic volume-to-volume registration using Normali...

  6. CT/MRI融合图像在盆腔肿瘤放疗靶区勾画中的应用%Application of CT/MRI Image Fusion in the Delineating of the Gross Tumor Target Volumes in the Radiotherapy for Pelvic Cavity Tumor

    Institute of Scientific and Technical Information of China (English)

    张海南; 汤日杰; 张书旭; 蔡霜

    2011-01-01

    Objective To study the value of application of CT/MRI image fusion in the delineating of the gross tumor target volumes in the radiotherapy for pelvic tumor in the middle-aged and elderly patients. Methods Nineteen patients suffering from pelvic tumor underwent CT and MRI examination within one week.All CT and MRI images were manually transported to the Nucletron PLATO Radiation Treatment Planning System(V 8.0, Philips medical corporation), and CT/MRI images were processed for image fusion.The experienced radiotherapeutic physicians delineated and analyzed the target volume of CT and MRI images, and gross tumor target volume of the CT/MR image fusion. Results The gross tumor target volume of the CT/MR image fusion relative the target volume of CT increased 6.29%,and relative MRI raised 11.84%,CT/MRI image fusion is superior to single CT and MRI image in the delineation of the gross tumor target volume, which was verified by test. Conclusion The technology of CT/MR image fusion can help to confirm target volume for pelvic tumor which will improve the accuracy in demarcating of the gross tumor target volume of pelvic cavity tumor, and promote the diagnosis and treatment of pelvic cavity tumor.%目的 探讨CT/MRI融合图像在中老年盆腔肿瘤放疗靶区(GTV)勾画中的应用价值.方法 19例盆腔肿瘤患者均在1周内分别进行CT、MRI异机非同步扫描.全部CT和MRI图像手工配准后传送至飞利浦公司的PINNACLE V8.0放射治疗计划系统,并进行图像融合.由有经验的放疗科医师对CT靶区、MRI靶区及CT与MR融合图像肿瘤靶区(GTV)进行勾画及评价分析.结果 GTVFUSION相对GTVCT提高了6.29%、相对GTVMRI提高了11.84%,融合图像对GTV的勾画明显优于单独CT图像或MRI图像.结论 CT/MRI图像融合技术有利于盆腔肿瘤靶区的确定,提高了临床对盆腔肿瘤靶区(GTV)勾画的准确率,利于患者的诊治.

  7. The use of fused PET/CT images for patient selection and radical radiotherapy target volume definition in patients with non-small cell lung cancer: Results of a prospective study with mature survival data

    International Nuclear Information System (INIS)

    Background and purpose: This prospective study investigated the impact of radiotherapy (RT)-planning FDG-PET/CT on management of non-small cell lung cancer (NSCLC). Materials and methods: Patients still eligible for radical RT after conventional staging underwent RT-planning PET/CT and, if disease was still treatable to 60 Gy, they entered our planning study, where visually-contoured tumour volumes derived with and without PET information were compared. If PET/CT detected advanced disease, palliative therapy was given. Overall survival (OS) for palliative and curative patients was compared. Results: Of 76 eligible patients, only 50 (66%) received radical chemoRT after PET/CT while 26 (34%) received palliative therapies because PET/CT detected advanced disease. Without PET, FDG-avid tumour would reside outside the planning target volume (PTV) in 36% of radical cases and in 25% 95% prescribed dose. OS for all patients was 56.8% and 24.9% at 1 and 4 years, respectively. OS for patients given chemoRT was 77.5% and 35.6% at 1 and 4 years, respectively and was 32% for stage IIIA patients at 4 years. OS for patients treated palliatively was inferior (P < 0.001); 16.3% and 4.1% at 1 and 4 years, respectively. Conclusions: Planning PET/CT frequently changed management and was associated with excellent survival. Survival data from this study were presented in part at the 2011 World Lung Cancer Conference, Amsterdam and planning data at the 2010 Annual Scientific Meeting of the American Society for Therapeutic Radiology and Oncology, Chicago

  8. Laser program annual report, 1977. Volume 2

    International Nuclear Information System (INIS)

    This volume contains detailed information on each of the following sections: (1) fusion target design, (2) target fabrication, (3) laser fusion experiments and analysis, (4) advanced lasers, (5) systems and applications studies, and (6) laser isotope separation program

  9. Laser program annual report, 1977. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Bender, C.F.; Jarman, B.D. (eds.)

    1978-07-01

    This volume contains detailed information on each of the following sections: (1) fusion target design, (2) target fabrication, (3) laser fusion experiments and analysis, (4) advanced lasers, (5) systems and applications studies, and (6) laser isotope separation program. (MOW)

  10. A teaching intervention in a contouring dummy run improved target volume delineation in locally advanced non-small cell lung cancer. Reducing the interobserver variability in multicentre clinical studies

    Energy Technology Data Exchange (ETDEWEB)

    Schimek-Jasch, Tanja; Prokic, Vesna; Doll, Christian; Grosu, Anca-Ligia; Nestle, Ursula [University Medical Center Freiburg, Department of Radiation Oncology, Freiburg (Germany); German Cancer Research Center (DKFZ), Heidelberg (Germany); German Cancer Consortium (DKTK) partner site: Freiburg, Heidelberg (Germany); Troost, Esther G.C. [Maastricht University Medical Centre, Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht (Netherlands); Ruecker, Gerta [University Medical Center Freiburg, Institute for Medical Biometry and Statistics, Centre for Medical Biometry and Medical Informatics, Freiburg (Germany); Avlar, Melanie [German Cancer Research Center (DKFZ), Heidelberg (Germany); Duncker-Rohr, Viola [Ortenau-Klinikum Offenburg-Gengenbach, Department of Radiation Oncology, Gengenbach (Germany); Mix, Michael [University Medical Center Freiburg, Department of Nuclear Medicine, Freiburg (Germany); German Cancer Research Center (DKFZ), Heidelberg (Germany); German Cancer Consortium (DKTK) partner site: Freiburg, Heidelberg (Germany)

    2015-02-10

    Interobserver variability in the definition of target volumes (TVs) is a well-known confounding factor in (multicentre) clinical studies employing radiotherapy. Therefore, detailed contouring guidelines are provided in the prospective randomised multicentre PET-Plan (NCT00697333) clinical trial protocol. This trial compares strictly FDG-PET-based TV delineation with conventional TV delineation in patients with locally advanced non-small cell lung cancer (NSCLC). Despite detailed contouring guidelines, their interpretation by different radiation oncologists can vary considerably, leading to undesirable discrepancies in TV delineation. Considering this, as part of the PET-Plan study quality assurance (QA), a contouring dummy run (DR) consisting of two phases was performed to analyse the interobserver variability before and after teaching. In the first phase of the DR (DR1), radiation oncologists from 14 study centres were asked to delineate TVs as defined by the study protocol (gross TV, GTV; and two clinical TVs, CTV-A and CTV-B) in a test patient. A teaching session was held at a study group meeting, including a discussion of the results focussing on discordances in comparison to the per-protocol solution. Subsequently, the second phase of the DR (DR2) was performed in order to evaluate the impact of teaching. Teaching after DR1 resulted in a reduction of absolute TVs in DR2, as well as in better concordance of TVs. The Overall Kappa(κ) indices increased from 0.63 to 0.71 (GTV), 0.60 to 0.65 (CTV-A) and from 0.59 to 0.63 (CTV-B), demonstrating improvements in overall interobserver agreement. Contouring DRs and study group meetings as part of QA in multicentre clinical trials help to identify misinterpretations of per-protocol TV delineation. Teaching the correct interpretation of protocol contouring guidelines leads to a reduction in interobserver variability and to more consistent contouring, which should consequently improve the validity of the overall study

  11. Distribution pattern of lymph node metastases and its implication in individualized radiotherapeutic clinical target volume delineation of regional lymph nodes in patients with stage IA to IIA cervical cancer

    International Nuclear Information System (INIS)

    To study the distribution pattern of lymph node metastases of stage IA to IIA cervical cancer and to clarify the individualized clinical target volume delineation of regional lymph nodes (CTVn). A total of 665 cases with International Federation Gynecology and Obstetrics stage IA to IIA cervical cancer who underwent radical hysterectomy and pelvic lymphadenectomy were retrospectively reviewed. The clinicopathological factors related to lymph node metastases were analyzed using logistic regression analysis. Pelvic lymph node metastases were found in 168 of 665 patients resulting in a metastasis rate of 25.3%. Binary logistic regression analysis showed that age, lymph vascular space involvement, and deep stromal invasion statistically influenced pelvic lymph node metastases (p = 0.017, < 0.001, < 0.001, respectively). Pathological morphology type, lymph node metastases of the obturator, the external iliac and internal iliac, and the para-aortic had a strong influence on lymph node metastases of the common iliac (p = 0.022, 0.003, < 0.001, 0.009, respectively). Tumor size and lymph node metastases of the common iliac were significantly related to lymph node metastases of the para-aortic (p = 0.045, < 0.001, respectively). Lymph node metastases of the obturator, the external iliac and internal iliac were strongly correlated to lymph node metastases of the circumflex iliac node distal to the external iliac node (CINDEIN; p = 0.027, 0.024, respectively). Factors related to lymph node metastases should be comprehensively considered to design and tailor CTVn for radiotherapy of cervical cancer. Selective regional irradiation including the correlated lymphatic drainage regions should be performed

  12. A teaching intervention in a contouring dummy run improved target volume delineation in locally advanced non-small cell lung cancer. Reducing the interobserver variability in multicentre clinical studies

    International Nuclear Information System (INIS)

    Interobserver variability in the definition of target volumes (TVs) is a well-known confounding factor in (multicentre) clinical studies employing radiotherapy. Therefore, detailed contouring guidelines are provided in the prospective randomised multicentre PET-Plan (NCT00697333) clinical trial protocol. This trial compares strictly FDG-PET-based TV delineation with conventional TV delineation in patients with locally advanced non-small cell lung cancer (NSCLC). Despite detailed contouring guidelines, their interpretation by different radiation oncologists can vary considerably, leading to undesirable discrepancies in TV delineation. Considering this, as part of the PET-Plan study quality assurance (QA), a contouring dummy run (DR) consisting of two phases was performed to analyse the interobserver variability before and after teaching. In the first phase of the DR (DR1), radiation oncologists from 14 study centres were asked to delineate TVs as defined by the study protocol (gross TV, GTV; and two clinical TVs, CTV-A and CTV-B) in a test patient. A teaching session was held at a study group meeting, including a discussion of the results focussing on discordances in comparison to the per-protocol solution. Subsequently, the second phase of the DR (DR2) was performed in order to evaluate the impact of teaching. Teaching after DR1 resulted in a reduction of absolute TVs in DR2, as well as in better concordance of TVs. The Overall Kappa(κ) indices increased from 0.63 to 0.71 (GTV), 0.60 to 0.65 (CTV-A) and from 0.59 to 0.63 (CTV-B), demonstrating improvements in overall interobserver agreement. Contouring DRs and study group meetings as part of QA in multicentre clinical trials help to identify misinterpretations of per-protocol TV delineation. Teaching the correct interpretation of protocol contouring guidelines leads to a reduction in interobserver variability and to more consistent contouring, which should consequently improve the validity of the overall study

  13. Patterns of Local-Regional Failure in Completely Resected Stage IIIA(N2) Non-Small Cell Lung Cancer Cases: Implications for Postoperative Radiation Therapy Clinical Target Volume Design

    International Nuclear Information System (INIS)

    Purpose: To analyze patterns of local-regional failure (LRF) for completely resected stage IIIA(N2) non-small cell lung cancer (NSCLC) patients treated in our hospital and to propose a clinical target volume (CTV) for postoperative radiation therapy (PORT) in these patients. Methods and Materials: From 2005 to 2011, consecutive patients with pT1-3N2 NSCLC who underwent complete resection in our hospital but who did not receive PORT were identified. The patterns of first LRF were assessed and evaluated as to whether these areas would be encompassed by our proposed PORT CTV. Results: With a median follow-up of 24 months, 173 of 250 patients (69.2%) experienced disease recurrence. Of the 54 patients with LRF as the first event, 48 (89%) had recurrence within the proposed PORT CTV, and 6 (11%) had failures occurring both within and outside the proposed CTV (all of which occurred in patients with right-lung cancer). Ninety-three percent of failure sites (104 of 112) would have been contained within the proposed PORT CTV. For left-sided lung cancer, the most common lymph node station failure site was 4R, followed by 7, 4L, 6, 10L, and 5. For right-sided lung cancer, the most common site was station 2R, followed by 10R, 4R, and 7. Conclusions: LRF following complete surgery was an important and potentially preventable pattern of failure in stage IIIA(N2) patients. Ipsilateral superior mediastinal recurrences dominated for right-sided tumors, whereas left-sided tumors frequently involved the bilateral superior mediastinum. Most of the LRF sites would have been covered by the proposed PORT CTV. A prospective investigation of patterns of failure after PORT (following our proposed CTV delineation guideline) is presently underway and will be reported in a separate analysis

  14. Quantum volume

    Science.gov (United States)

    Ryabov, V. A.

    2015-08-01

    Quantum systems in a mechanical embedding, the breathing mode of a small particles, optomechanical system, etc. are far not the full list of examples in which the volume exhibits quantum behavior. Traditional consideration suggests strain in small systems as a result of a collective movement of particles, rather than the dynamics of the volume as an independent variable. The aim of this work is to show that some problem here might be essentially simplified by introducing periodic boundary conditions. At this case, the volume is considered as the independent dynamical variable driven by the internal pressure. For this purpose, the concept of quantum volume based on Schrödinger’s equation in 𝕋3 manifold is proposed. It is used to explore several 1D model systems: An ensemble of free particles under external pressure, quantum manometer and a quantum breathing mode. In particular, the influence of the pressure of free particle on quantum oscillator is determined. It is shown also that correction to the spectrum of the breathing mode due to internal degrees of freedom is determined by the off-diagonal matrix elements of the quantum stress. The new treatment not using the “force” theorem is proposed for the quantum stress tensor. In the general case of flexible quantum 3D dynamics, quantum deformations of different type might be introduced similarly to monopole mode.

  15. Sequential (gemcitabine/vinorelbine) and concurrent (gemcitabine) radiochemotherapy with FDG-PET-based target volume definition in locally advanced non-small cell lung cancer: first results of a phase I/II study

    International Nuclear Information System (INIS)

    The aim of the study was to determine the maximal tolerated dose (MTD) of gemcitabine every two weeks concurrent to radiotherapy, administered during an aggressive program of sequential and simultaneous radiochemotherapy for locally advanced, unresectable non-small cell lung cancer (NSCLC) and to evaluate the efficacy of this regime in a phase II study. 33 patients with histologically confirmed NSCLC were enrolled in a combined radiochemotherapy protocol. 29 patients were assessable for evaluation of toxicity and tumor response. Treatment included two cycles of induction chemotherapy with gemcitabine (1200 mg/m2) and vinorelbine (30 mg/m2) at day 1, 8 and 22, 29 followed by concurrent radiotherapy (2.0 Gy/d; total dose 66.0 Gy) and chemotherapy with gemcitabine every two weeks at day 43, 57 and 71. Radiotherapy planning included [18F] fluorodeoxyglucose positron emission tomography (FDG PET) based target volume definition. 10 patients were included in the phase I study with an initial gemcitabine dose of 300 mg/m2. The dose of gemcitabine was increased in steps of 100 mg/m2 until the MTD was realized. MTD was defined for the patient group receiving gemcitabine 500 mg/m2 due to grade 2 (next to grade 3) esophagitis in all patients resulting in a mean body weight loss of 5 kg (SD = 1.4 kg), representing 8% of the initial weight. These patients showed persisting dysphagia 3 to 4 weeks after completing radiotherapy. In accordance with expected complications as esophagitis, dysphagia and odynophagia, we defined the MTD at this dose level, although no dose limiting toxicity (DLT) grade 3 was reached. In the phase I/II median follow-up was 15.7 months (4.1 to 42.6 months). The overall response rate after completion of therapy was 64%. The median overall survival was 19.9 (95% CI: [10.1; 29.7]) months for all eligible patients. The median disease-free survival for all patients was 8.7 (95% CI: [2.7; 14.6]) months. After induction chemotherapy, the maximum tolerated dose

  16. Sequential (gemcitabine/vinorelbine and concurrent (gemcitabine radiochemotherapy with FDG-PET-based target volume definition in locally advanced non-small cell lung cancer: first results of a phase I/II study

    Directory of Open Access Journals (Sweden)

    Stanzel Sven

    2007-06-01

    Full Text Available Abstract Background The aim of the study was to determine the maximal tolerated dose (MTD of gemcitabine every two weeks concurrent to radiotherapy, administered during an aggressive program of sequential and simultaneous radiochemotherapy for locally advanced, unresectable non-small cell lung cancer (NSCLC and to evaluate the efficacy of this regime in a phase II study. Methods 33 patients with histologically confirmed NSCLC were enrolled in a combined radiochemotherapy protocol. 29 patients were assessable for evaluation of toxicity and tumor response. Treatment included two cycles of induction chemotherapy with gemcitabine (1200 mg/m2 and vinorelbine (30 mg/m2 at day 1, 8 and 22, 29 followed by concurrent radiotherapy (2.0 Gy/d; total dose 66.0 Gy and chemotherapy with gemcitabine every two weeks at day 43, 57 and 71. Radiotherapy planning included [18F] fluorodeoxyglucose positron emission tomography (FDG PET based target volume definition. 10 patients were included in the phase I study with an initial gemcitabine dose of 300 mg/m2. The dose of gemcitabine was increased in steps of 100 mg/m2 until the MTD was realized. Results MTD was defined for the patient group receiving gemcitabine 500 mg/m2 due to grade 2 (next to grade 3 esophagitis in all patients resulting in a mean body weight loss of 5 kg (SD = 1.4 kg, representing 8% of the initial weight. These patients showed persisting dysphagia 3 to 4 weeks after completing radiotherapy. In accordance with expected complications as esophagitis, dysphagia and odynophagia, we defined the MTD at this dose level, although no dose limiting toxicity (DLT grade 3 was reached. In the phase I/II median follow-up was 15.7 months (4.1 to 42.6 months. The overall response rate after completion of therapy was 64%. The median overall survival was 19.9 (95% CI: [10.1; 29.7] months for all eligible patients. The median disease-free survival for all patients was 8.7 (95% CI: [2.7; 14.6] months. Conclusion

  17. Defining the “Hostile Pelvis” for Intensity Modulated Radiation Therapy: The Impact of Anatomic Variations in Pelvic Dimensions on Dose Delivered to Target Volumes and Organs at Risk in Patients With High-Risk Prostate Cancer Treated With Whole Pelvic Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yirmibeşoğlu Erkal, Eda, E-mail: eyirmibesoglu@yahoo.com [Department of Radiation Oncology, Kocaeli University Faculty of Medicine, Kocaeli (Turkey); Karabey, Sinan [Department of Radiation Oncology, Kocaeli University Faculty of Medicine, Kocaeli (Turkey); Karabey, Ayşegül [Department of Radiation Oncology, Kocaeli State Hospital, Kocaeli (Turkey); Hayran, Mutlu [Department of Preventive Oncology, Hacettepe University Cancer Institute, Ankara (Turkey); Erkal, Haldun Şükrü [Department of Radiation Oncology, Sakarya University Faculty of Medicine, Sakarya (Turkey)

    2015-07-15

    Purpose: The aim of this study was to evaluate the impact of variations in pelvic dimensions on the dose delivered to the target volumes and the organs at risk (OARs) in patients with high-risk prostate cancer (PCa) to be treated with whole pelvic radiation therapy (WPRT) in an attempt to define the hostile pelvis in terms of intensity modulated radiation therapy (IMRT). Methods and Materials: In 45 men with high-risk PCa to be treated with WPRT, the target volumes and the OARs were delineated, the dose constraints for the OARs were defined, and treatment plans were generated according to the Radiation Therapy Oncology Group 0924 protocol. Six dimensions to reflect the depth, width, and height of the bony pelvis were measured, and 2 indexes were calculated from the planning computed tomographic scans. The minimum dose (D{sub min}), maximum dose (D{sub max}), and mean dose (D{sub mean}) for the target volumes and OARs and the partial volumes of each of these structures receiving a specified dose (V{sub D}) were calculated from the dose-volume histograms (DVHs). The data from the DVHs were correlated with the pelvic dimensions and indexes. Results: According to an overall hostility score (OHS) calculation, 25 patients were grouped as having a hospitable pelvis and 20 as having a hostile pelvis. Regarding the OHS grouping, the DVHs for the bladder, bowel bag, left femoral head, and right femoral head differed in favor of the hospitable pelvis group, and the DVHs for the rectum differed for a range of lower doses in favor of the hospitable pelvis group. Conclusions: Pelvimetry might be used as a guide to define the challenging anatomy or the hostile pelvis in terms of treatment planning for IMRT in patients with high-risk PCa to be treated with WPRT.

  18. Optimal margins between clinical target volume (CTV) and planning target volume (PTV)

    OpenAIRE

    Hjulfors, Emmelie Maria

    2011-01-01

    The purpose of this study was to estimate the CTV-PTV margin required for prostate and head and neck cancer treatments at the radiotherapy departments of Karolinska University Hospital.    Portal image data from patients treated at the radiotherapy departments during the period of 2009-2011 was used to estimate the set-up displacements for each treatment area. By using the acquired images the magnitude of the systematic, i.e. preparatory, and random, i.e. execution, error was determined in th...

  19. Specification of volume and dose in radiotherapy

    International Nuclear Information System (INIS)

    As a result of a questionnaire about dose and volume specifications in radiotherapy in the Nordic countries, a group has been set up to propose common recommendations for these countries. The proposal is partly based on ICRU 50, but with major extensions. These extensions fall into three areas: patient geometry, treatment geometry, and dose specifications. For patient geometry and set-up one need alignment markings and anatomical reference points, the latter can be divided into internal and external reference points. These points are necessary to get relationships between coordinate systems related to patient and to treatment unit. For treatment geometry the main volume will be an anatomical target volume which just encompass the clinical target volume with all its variations and movements. This anatomical volume are the most suitable volume for prescription, optimization and reporting dose. A set-up margin should be added to the beam periphery in beams-eye-view to get the minimum size and shape of the beam. For dose specification the most important parameter for homogeneous dose distributions is the arithmetic mean of dose to the anatomical target volume together with its standard deviation. In addition the dose to the ICRU reference point should be reported for intercomparison, together with minimum and maximum doses or dose volume histograms for the anatomical target volume. (author)

  20. CERN: Fixed target targets

    International Nuclear Information System (INIS)

    Full text: While the immediate priority of CERN's research programme is to exploit to the full the world's largest accelerator, the LEP electron-positron collider and its concomitant LEP200 energy upgrade (January, page 1), CERN is also mindful of its long tradition of diversified research. Away from LEP and preparations for the LHC proton-proton collider to be built above LEP in the same 27-kilometre tunnel, CERN is also preparing for a new generation of heavy ion experiments using a new source, providing heavier ions (April 1992, page 8), with first physics expected next year. CERN's smallest accelerator, the LEAR Low Energy Antiproton Ring continues to cover a wide range of research topics, and saw a record number of hours of operation in 1992. The new ISOLDE on-line isotope separator was inaugurated last year (July, page 5) and physics is already underway. The remaining effort concentrates around fixed target experiments at the SPS synchrotron, which formed the main thrust of CERN's research during the late 1970s. With the SPS and LEAR now approaching middle age, their research future was extensively studied last year. Broadly, a vigorous SPS programme looks assured until at least the end of 1995. Decisions for the longer term future of the West Experimental Area of the SPS will have to take into account the heavy demand for test beams from work towards experiments at big colliders, both at CERN and elsewhere. The North Experimental Area is the scene of larger experiments with longer lead times. Several more years of LEAR exploitation are already in the pipeline, but for the longer term, the ambitious Superlear project for a superconducting ring (January 1992, page 7) did not catch on. Neutrino physics has a long tradition at CERN, and this continues with the preparations for two major projects, the Chorus and Nomad experiments (November 1991, page 7), to start next year in the West Area. Delicate neutrino oscillation effects could become

  1. Sputter target

    Science.gov (United States)

    Gates, Willard G.; Hale, Gerald J.

    1980-01-01

    The disclosure relates to an improved sputter target for use in the deposition of hard coatings. An exemplary target is given wherein titanium diboride is brazed to a tantalum backing plate using a gold-palladium-nickel braze alloy.

  2. Multi-scenario based robust intensity-modulated proton therapy (IMPT) plans can account for set-up errors more effectively in terms of normal tissue sparing than planning target volume (PTV) based intensity-modulated photon plans in the head and neck region

    International Nuclear Information System (INIS)

    In a previous report, we compared the conformity of robust intensity-modulated proton therapy (IMPT) plans with that of helical tomotherapy plans for re-irradiations of head and neck carcinomas using a fixed set-up error of 2 mm. Here, we varied the maximum set-up errors between 0 and 5 mm and compared the robust IMPT-plans with planning target volume (PTV) based intensity-modulated photon therapy (IMRT). Seven patients were treated with a PTV-based tomotherapy plan. Set-up margins of 0, 2, and 5 mm were subtracted from the PTV to generate target volumes (TV) TV0mm, TV2mm, and TV5mm, for which robust IMPT-plans were created assuming range uncertainties of ±3.5% and using worst case optimization assuming set-up errors of 0, 2, and 5 mm, respectively. Robust optimization makes use of the feature that set-up errors in beam direction alone do not affect the distal and proximal margin for that beam. With increasing set-up errors, the body volumes that were exposed to a selected minimum dose level between 20% and 95% of the prescribed dose decreased. In IMPT-plans with 0 mm set-up error, the exposed body volumes were on average 6.2% ± 0.9% larger than for IMPT-plans with 2 mm set-up error, independent of the considered dose level (p < 0.0001, F-test). In IMPT-plans accounting for 5 mm set-up error, the exposed body volumes were by 11.9% ± 0.8% smaller than for IMPT-plans with 2 mm set-up error at a fixed minimum dose (p < 0.0001, F-test). This set-up error dependence of the normal tissue exposure around the TV in robust IMPT-plans corresponding to the same IMRT-plan led to a decrease in the mean dose to the temporal lobes and the cerebellum, and in the D2% of the brain stem or spinal cord with increasing set-up errors considered during robust IMPT-planning. For recurrent head and neck cancer, robust IMPT-plan optimization led to a decrease in normal tissue exposure with increasing set-up error for target volumes corresponding to the same PTV

  3. Renormalized Volume

    CERN Document Server

    Gover, A Rod

    2016-01-01

    For any conformally compact manifold with hypersurface boundary we define a canonical renormalized volume functional and compute an explicit, holographic formula for the corresponding anomaly. For the special case of asymptotically Einstein manifolds, our method recovers the known results. The anomaly does not depend on any particular choice of regulator, but the coefficients of divergences do. We give explicit formulae for these divergences valid for any choice of regulating hypersurface; these should be relevant to recent studies of quantum corrections to entanglement entropies. The anomaly is expressed as a conformally invariant integral of a local Q-curvature that generalizes the Branson Q-curvature by including data of the embedding. In each dimension this canonically defines a higher dimensional generalization of the Willmore energy/rigid string action. We show that the variation of these energy functionals is exactly the obstruction to solving a singular Yamabe type problem with boundary data along the...

  4. Target capture and target ghosts

    Science.gov (United States)

    Auerbach, Steven P.

    1996-05-01

    Optimal detection methods for small targets rely on whitened matched filters, which convolve the measured data with the signal model, and whiten the result with the noise covariance. In real-world implementations of such filters, the noise covariance must be estimated from the data, and the resulting covariance estimate may be corrupted by presence of the target. The resulting loss in SNR is called 'target capture'. Target capture is often thought to be a problem only for bright targets. This presentation shows that target capture also arises for dim targets, leading to an SNR loss which is independent of target strength and depends on the averaging method used to estimate the noise covariance. This loss is due to a 'coherent beat' between the true noise and that portion of the estimated noise covariance due to the target. This beat leads to 'ghost targets', which diminish the target SNR by producing a negative target ghost at the target's position. A quantitative estimate of this effect will be given, and shown to agree with numerical results. The effect of averaging on SNR is also discussed for data scenes with synthetic injected targets, in cases where the noise covariance is estimated using 'no target' data. For these cases, it is shown that the so-called 'optimal' filter, which uses the true noise covariance, is actually worse than a 'sub-optimal' filter which estimates the noise from scene. This apparent contradiction is resolved by showing that the optimal filter is best if the same filter is used for many scenes, but is outperformed by a filter adapted to a specific scene.

  5. Direct Volume Rendering of Curvilinear Volumes

    Science.gov (United States)

    Vaziri, Arsi; Wilhelms, J.; Challinger, J.; Alper, N.; Ramamoorthy, S.; Kutler, Paul (Technical Monitor)

    1998-01-01

    Direct volume rendering can visualize sampled 3D scalar data as a continuous medium, or extract features. However, it is generally slow. Furthermore, most algorithms for direct volume rendering have assumed rectilinear gridded data. This paper discusses methods for using direct volume rendering when the original volume is curvilinear, i.e. is divided into six-sided cells which are not necessarily equilateral hexahedra. One approach is to ray-cast such volumes directly. An alternative approach is to interpolate the sample volumes to a rectilinear grid, and use this regular volume for rendering. Advantages and disadvantages of the two approaches in terms of speed and image quality are explored.

  6. Impact of planning target volume (PTV) on the late toxicity and on survival without biochemical relapse among patients suffering from a prostate cancer and treated by intensity-modulated conformational irradiation guided by three-dimensional echography; Impact du volume cible previsionnel (PTV) sur la toxicite tardive et la survie sans rechute biochimique chez des patients atteints d'un cancer de la prostate traite par irradiation conformationnalle avec modulation d'intensite guidee par echographie tridimensionnelle

    Energy Technology Data Exchange (ETDEWEB)

    Mirjolet, C.; Crehange, G.; Gauthier, M.; Azelie, C.; Martin, E.; Truc, G.; Peignaux, K.; Bonnetain, F.; Naudy, S.; Maingon, P. [Centre Georges Francois Leclerc, 21 - Dijon (France)

    2010-10-15

    As several dosimetric studies demonstrated a theoretical benefit of the image-guided and intensity-modulated conformational radiotherapy (IMRT) to reduce the planning target volume (PTV) margins and irradiated healthy tissues, the authors report and discuss data obtained on 170 men suffering from a prostate cancer and treated by IMRT with a daily repositioning performed using a three-dimensional echography. Patients have been classified in two groups with respect to the margin value. Toxicity has been assessed and survival without biochemical progress has been computed. Few grade 2 genital-urinary effects have been observed. Only patients having a Gleason score greater than 7 or suffering from diabetes have a lower survival rate without biochemical advance. Short communication

  7. Influence of CT/MRI Fusion Image on Target Volume and 3-D Conformal Radiotherapy in Non-small Cell Lung Cancer with Brain Metastasis%CT/MRI诊断影像融合对非小细胞肺癌脑转移瘤靶区及三维适形治疗影响

    Institute of Scientific and Technical Information of China (English)

    杨金山; 魏永兵; 侯超; 李静; 朱瑞霞

    2014-01-01

    目的:比较CT图像和CT/MRI融合图像来源的肺癌脑转移肿瘤靶区,评价CT/MRI融合靶区容积应用于三维适形放射治疗时,对治疗剂量的影响。方法:将20例非小细胞肺癌脑转移患者的增强CT和MRI扫描的图像传送至图像处理工作站,在CT和CT/MRI融合图像上分别勾画GTV和周围重要的器官。每个病例分别在CT图像和CT/MRI融合图像都做1个三维适形放射治疗计划。肿瘤的处方剂量为60 Gy,比较2个治疗计划中肿瘤靶区的95%容积(D95)受照平均剂量、周围正常组织的5%容积(D5)受照平均剂量。结果:CT/MRI融合图像上的肿瘤靶区平均比CT上的肿瘤靶区大21.32%。用CT上勾画的靶区有一部分肿瘤处于低剂量区,CT/MRI融合图像上的靶区D95剂量分布较好,但在周围重要器官的剂量分布较高。结论:CT/MRI融合图像有助于靶区的确定,在三维适形放射治疗计划上的肿瘤靶区剂量分布足够,能提高靶区勾画的准确性,更利于精确放疗的实施。%Objective:To compare the CT images and CT/MRI images fusion sources of lung cancer with brain metastasis tumor target,and to evaluae the effects of dose for treatment on target volume CT/MRI fusion for three-dimensional conformal radiotherapy. Method:The enhancement CT and MRI scan image of 20 patients with brain metastases from non-small cell lung cancer was transfer to image processing workstation,GTV and surrounding vital organs on CT and CT/MRI images fusion was delineated respectively. A three-dimensional conformal radiotherapy plan was done in CT images and CT/MRI fusion images of ach case. Tumor prescription dose was 60 Gy. Compared the average dose of the 95%volume(D95)tumor target,the average dose of the 5%of the normal tissue around of the two treatment plans. Result:The tumor targets of the CT/MRI images fusion was greater than those of the CT tumor targets on average 21.32%. A part of the tumor was

  8. Antiproton Target

    CERN Multimedia

    1980-01-01

    Antiproton target used for the AA (antiproton accumulator). The first type of antiproton production target used from 1980 to 1982 comprised a rod of copper 3mm diameter and 120mm long embedded in a graphite cylinder that was itself pressed into a finned aluminium container. This assembly was air-cooled and it was used in conjunction with the Van der Meer magnetic horn. In 1983 Fermilab provided us with lithium lenses to replace the horn with a view to increasing the antiproton yield by about 30%. These lenses needed a much shorter target made of heavy metal - iridium was chosen for this purpose. The 50 mm iridium rod was housed in an extension to the original finned target container so that it could be brought very close to the entrance to the lithium lens. Picture 1 shows this target assembly and Picture 2 shows it mounted together with the lithium lens. These target containers had a short lifetime due to a combination of beam heating and radiation damage. This led to the design of the water-cooled target in...

  9. Is it always possible to respect dose constraints for target volumes and organs at risk within the frame of breast radiotherapy after conservative treatment?; Le respect des contraintes de dose aux volumes cibles et aux organes a risque est-il toujours possible dans le cadre d'une radiotherapie du sein apres traitement conservateur?

    Energy Technology Data Exchange (ETDEWEB)

    Renoult, F.; Faivre, J.C.; Charra Brunaud, C.; Tournier-Rangeard, L.; Lostette, J.; Huger, S.; Marchesi, V.; Peiffert, D.; Marchal, C. [Centre Alexis-Vautrin, 54 - Nancy (France); Xemard, S. [Centre hospitalier Jean-Monnet, 88 - Epinal (France)

    2010-10-15

    The use of three-dimensional breast radiotherapy after a conservative treatment allowed cardiotoxicity as well as the dose delivered to lungs to be significantly reduced. However several bibliographic references give different dose constraints. Based on the constraints given by the Oncological radiotherapy French Society (SFRO), the authors analysed whether these recommendations could be actually respected within a daily practice. Based on a sample of 91 patients, the authors collected the following data: mammary gland volumes receiving respectively 95 and 107% of the dose before the boost calculation, heart and pulmonary volumes receiving different dose levels. Coverage constraints are indicated. It appears that the present technique does not allow the constraints to be respected in a majority of cases. Short communication

  10. Volumes in Hyperbolic Space

    OpenAIRE

    Laternser, Christina

    2011-01-01

    This paper focuses on the investigation of volumes of large Coxeter hyperbolic polyhedron. First, the paper investigates the smallest possible volume for a large Coxeter hyperbolic polyhedron and then looks at the volume of pyramids with one vertex at infinity.

  11. ICF target positioning robot system

    International Nuclear Information System (INIS)

    Based on the function analysis of target positioner for inertial confinement fusion, a kind of ICF target positioning robot system is designed to realize the adjustment and the alignment of a target. The robot system includes a target storage sub-system, a target exchange subsystem, a target transport subsystem and a 6-degree of freedom precision parallel robot subsystem, the structure and principle of every subsystem are dissertated. The system realizes micro scale position by parallel structure which is in the front of the system, and has the advantages of low mass, high stiffness, small cone angle, small volume and high precision. The robot system can position a target into a very small micro scale scope around the center of the target chamber whose diameter is several meters, the precision of the position reaches micro scale. Motion parameter of the positioning robot system has been tested. Experiment proves that the robot system has realized precision target position and target exchange on the condition of vacuum. (authors)

  12. Targeted Learning

    CERN Document Server

    van der Laan, Mark J

    2011-01-01

    The statistics profession is at a unique point in history. The need for valid statistical tools is greater than ever; data sets are massive, often measuring hundreds of thousands of measurements for a single subject. The field is ready to move towards clear objective benchmarks under which tools can be evaluated. Targeted learning allows (1) the full generalization and utilization of cross-validation as an estimator selection tool so that the subjective choices made by humans are now made by the machine, and (2) targeting the fitting of the probability distribution of the data toward the targe

  13. CT与MRI图像融合对脑转移瘤三维适形放疗靶区的影响%The influence of target volume by CT/MRI image fusion on brain metastasis's three-dimensional conformal radiotherapy

    Institute of Scientific and Technical Information of China (English)

    陈苏玮; 袁锋; 林志仁; 王伟锋

    2012-01-01

    Objective To improve the accuracy of delineating three-dimensional conformal radiotherapy target volume by comparing the difference between computed tomography(CT)/magnetic resonance imaging (MRI) image fusion on brain metastasis area and CT's target area. Methods CT's images and MRI's images collected from 25 cases with brain metastasis in the same period were transmitted to image processing workstation and fused into CT/MRI images, and then 41 pairs of gross tumor volume (GTV) were delineated in CT and CT/MRI, and finally difference was compared between the two group. Results The value of GTVCT in 41 pairs from 25 cases was (31.75±9.93) cm3 and in GTVCT/MRI was (28.92±8.25) cm3. Among 41 control groups, the number of the accuracy of GTVCT lower than that of GTVCT/MRI was 18, GTCCT higher than that of GTVCT/MRI was 23. Conclusion The improving accuracy of brain metastasis's target volume sketched by CT/MRI image fusion is more suitable for three-dimensional conformal radiotherapy.%目的 研究CT与MRI图像融合的脑转移瘤靶区与CT图像靶区的不同,提高三维适形放疗靶区勾画的准确性.方法 同期采集25例脑转移瘤患者的CT和MRI图像,传送至图像处理工作站融合成CT/MRI图像,分别在CT及CT/MRI融合图像勾画41组GTV,比较两种图像勾画的GTV的差别.结果 25例患者共41组靶区的GTVcr为(31.75±9.93)cm3,GTVCT/MRI为(28.92±8.25)cm3.41个对照组中,GTVCr <GTVCT/MRI为18个,GTVCT >GTVCT/MRI为23个.结论 采用CT/MRI融合后图像勾画的脑转移瘤靶区精确度提高,更适合于三维立体适形放疗.

  14. Estimation of daily interfractional larynx residual setup error after isocentric alignment for head and neck radiotherapy: Quality-assurance implications for target volume and organ-at-risk margination using daily CT-on-rails imaging

    Science.gov (United States)

    Baron, Charles A.; Awan, Musaddiq J.; Mohamed, Abdallah S. R.; Akel, Imad; Rosenthal, David I.; Gunn, G. Brandon; Garden, Adam S.; Dyer, Brandon A.; Court, Laurence; Sevak, Parag R; Kocak-Uzel, Esengul; Fuller, Clifton D.

    2016-01-01

    Larynx may alternatively serve as a target or organ-at-risk (OAR) in head and neck cancer (HNC) image-guided radiotherapy (IGRT). The objective of this study was to estimate IGRT parameters required for larynx positional error independent of isocentric alignment and suggest population–based compensatory margins. Ten HNC patients receiving radiotherapy (RT) with daily CT-on-rails imaging were assessed. Seven landmark points were placed on each daily scan. Taking the most superior anterior point of the C5 vertebra as a reference isocenter for each scan, residual displacement vectors to the other 6 points were calculated post-isocentric alignment. Subsequently, using the first scan as a reference, the magnitude of vector differences for all 6 points for all scans over the course of treatment were calculated. Residual systematic and random error, and the necessary compensatory CTV-to-PTV and OAR-to-PRV margins were calculated, using both observational cohort data and a bootstrap-resampled population estimator. The grand mean displacements for all anatomical points was 5.07mm, with mean systematic error of 1.1mm and mean random setup error of 2.63mm, while bootstrapped POIs grand mean displacement was 5.09mm, with mean systematic error of 1.23mm and mean random setup error of 2.61mm. Required margin for CTV-PTV expansion was 4.6mm for all cohort points, while the bootstrap estimator of the equivalent margin was 4.9mm. The calculated OAR-to-PRV expansion for the observed residual set-up error was 2.7mm, and bootstrap estimated expansion of 2.9mm. We conclude that the interfractional larynx setup error is a significant source of RT set-up/delivery error in HNC both when the larynx is considered as a CTV or OAR. We estimate the need for a uniform expansion of 5mm to compensate for set up error if the larynx is a target or 3mm if the larynx is an OAR when using a non-laryngeal bony isocenter. PMID:25679151

  15. Volume definition system for treatment planning

    International Nuclear Information System (INIS)

    Purpose: Volume definition is a difficult and time consuming task in 3D treatment planning. We have studied a systems approach for constructing an efficient and reliable set of tools for volume definition. Our intent is to automate body outline, air cavities and bone volume definition and accelerate definition of other anatomical structures. An additional focus is on assisting in definition of CTV and PTV. The primary goals of this work are to cut down the time used in contouring and to improve the accuracy of volume definition. Methods: We used the following tool categories: manual, semi-automatic, automatic, structure management, target volume definition, and visualization tools. The manual tools include mouse contouring tools with contour editing possibilities and painting tools with a scaleable circular brush and an intelligent brush. The intelligent brush adapts its shape to CT value boundaries. The semi-automatic tools consist of edge point chaining, classical 3D region growing of single segment and competitive volume growing of multiple segments. We tuned the volume growing function to take into account both local and global region image values, local volume homogeneity, and distance. Heuristic seeding followed with competitive volume growing finds the body outline, couch and air automatically. The structure management tool stores ICD-O coded structures in a database. The codes have predefined volume growing parameters and thus are able to accommodate the volume growing dissimilarity function for different volume types. The target definition tools include elliptical 3D automargin for CTV to PTV transformation and target volume interpolation and extrapolation by distance transform. Both the CTV and the PTV can overlap with anatomical structures. Visualization tools show the volumes as contours or color wash overlaid on an image and displays voxel rendering or translucent triangle mesh rendering in 3D. Results: The competitive volume growing speeds up the

  16. Ovarian volume throughout life

    DEFF Research Database (Denmark)

    Kelsey, Thomas W; Dodwell, Sarah K; Wilkinson, A Graham;

    2013-01-01

    cancer. To date there is no normative model of ovarian volume throughout life. By searching the published literature for ovarian volume in healthy females, and using our own data from multiple sources (combined n=59,994) we have generated and robustly validated the first model of ovarian volume from...... to about 2.8 mL (95% CI 2.7-2.9 mL) at the menopause and smaller volumes thereafter. Our model allows us to generate normal values and ranges for ovarian volume throughout life. This is the first validated normative model of ovarian volume from conception to old age; it will be of use in the...

  17. Multivariate volume rendering

    Energy Technology Data Exchange (ETDEWEB)

    Crawfis, R.A.

    1996-03-01

    This paper presents a new technique for representing multivalued data sets defined on an integer lattice. It extends the state-of-the-art in volume rendering to include nonhomogeneous volume representations. That is, volume rendering of materials with very fine detail (e.g. translucent granite) within a voxel. Multivariate volume rendering is achieved by introducing controlled amounts of noise within the volume representation. Varying the local amount of noise within the volume is used to represent a separate scalar variable. The technique can also be used in image synthesis to create more realistic clouds and fog.

  18. Accelerator target

    Energy Technology Data Exchange (ETDEWEB)

    Schlyer, David J. (Bellport, NY); Ferrieri, Richard A. (Patchogue, NY); Koehler, Conrad (Miller Place, NY)

    1999-01-01

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression.

  19. IUCF liquid hydrogen target system

    International Nuclear Information System (INIS)

    A liquid hydrogen or deuterium target system is described for use with intermediate energy light ion beams at IUCF. In its present use as a production target for polarized neutrons, the target cell is mounted within the beamline. Thus, certain safety features are required which prevent a possible hydrogen explosion inside the beamline or the cyclotron. These safety devices include an acoustical delay line which slows the hydrogen gas shock wave and a fast valve which closes before any large volume of escaping gas reaches it. Other safety interlocks to reduce the chances of target cell breakage and to quickly shut off ignition sources are discussed. A device involving a variable heat load which is coupled directly to the cryocondenser and is used to continually monitor and stabilize the pressure and temperature of the liquid hydrogen is described here

  20. Layered volume splatting

    OpenAIRE

    Schlegel, P.; Pajarola, R.

    2009-01-01

    We present a new layered, hardware-accelerated splatting algorithm for volume rendering. Layered volume splatting features the speed benefits of fast axis-aligned pre-classified sheet-buffer splatting while at the same time exhibiting display quality comparable to high-quality post-classified view-aligned sheet-buffer splatting. Additionally, we enhance the quality by using a more accurate approximation of the volume rendering integral. Commonly, the extinction coefficient of the volume r...

  1. CELL VOLUME CONFERENCES

    OpenAIRE

    V. Štrbák

    2016-01-01

    This mini-review describes the history of cell volume conferences with the emphasis on the research of cell volume sensitive peptide exocytosis initiated by Prof. Monte A. Greer as well as the recent achievements on the study of the mechanisms of cell volume adjustment and their implications in the regulation of metabolism, gene expression, cell proliferation and death.

  2. Liquid hydrogen target cooled by circulating helium

    International Nuclear Information System (INIS)

    Structure and characteristics of a liquid hydrogen target, where hydrogen is liquefied with liquid helium flow using evaporation heat of liquid helium and vapour cold, are described. Good thermal insulation of liquid helium supply line permits to remove out of the target the most volumetric and heavy component - helium tank - and to supply liquid helium along spreaded pipeline from the Dewar helium flask. It results in considerable reduction of dimensions and weight, the structure simplification and work facilitation with the target. The target having a working volume of 400 mm length and 60 mm diameter was tested. Vacuum casing of the working volume was made of foam plastic, heat flow to the working volume is equal to 1.5 W. Achieving mode of operation including structure cooling and hydrogen liquefaction took approximately 3 h, liquid helium flow rate for liquefaction of 1 l hydrogen is 2.7 l. Liquid helium flow rate in the mode of operation was equal to 0.7 l/h, i.e. target operation period without adding liquid helium to the Dewar flask is 4-5 days. The target described is notable for simplicity in fabrication, reliability in operation and is very suitable for using in experiment as compared to existing targets with hydrogen liquefaction with liquid helium. Unit structure of the target enables to easily change its configuration relative to problems of concrete physical experiment

  3. Targeted multi-pinhole SPECT

    International Nuclear Information System (INIS)

    Small-animal single photon emission computed tomography (SPECT) with focused multi-pinhole collimation geometries allows scanning modes in which large amounts of photons can be collected from specific volumes of interest. Here we present new tools that improve targeted imaging of specific organs and tumours, and validate the effects of improved targeting of the pinhole focus. A SPECT system with 75 pinholes and stationary detectors was used (U-SPECT-II). An XYZ stage automatically translates the animal bed with a specific sequence in order to scan a selected volume of interest. Prior to stepping the animal through the collimator, integrated webcams acquire images of the animal. Using sliders, the user designates the desired volume to be scanned (e.g. a xenograft or specific organ) on these optical images. Optionally projections of an atlas are overlaid semiautomatically to locate specific organs. In order to assess the effects of more targeted imaging, scans of a resolution phantom and a mouse myocardial phantom, as well as in vivo mouse cardiac and tumour scans, were acquired with increased levels of targeting. Differences were evaluated in terms of count yield, hot rod visibility and contrast-to-noise ratio. By restricting focused SPECT scans to a 1.13-ml resolution phantom, count yield was increased by a factor 3.6, and visibility of small structures was significantly enhanced. At equal noise levels, the small-lesion contrast measured in the myocardial phantom was increased by 42%. Noise in in vivo images of a tumour and the mouse heart was significantly reduced. Targeted pinhole SPECT improves images and can be used to shorten scan times. Scan planning with optical cameras provides an effective tool to exploit this principle without the necessity for additional X-ray CT imaging. (orig.)

  4. Calf muscle volume estimates: Implications for Botulinum toxin treatment?

    DEFF Research Database (Denmark)

    Bandholm, Thomas Quaade; Sonne-Holm, Stig; Thomsen, Carsten;

    2007-01-01

    An optimal botulinum toxin dose may be related to the volume of the targeted muscle. We investigated the suitability of using ultrasound and anthropometry to estimate gastrocnemius and soleus muscle volume. Gastrocnemius and soleus muscle thickness was measured in 11 cadaveric human legs, using...

  5. Volume Regulated Channels

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjær

    - serves a multitude of functions in the mammalian cell, regulating the membrane potential (Em), cell volume, protein activity and the driving force for facilitated transporters giving Cl- and Cl- channels a major potential of regulating cellular function. These functions include control of the cell cycle...... of volume perturbations evolution have developed system of channels and transporters to tightly control volume homeostasis. In the past decades evidence has been mounting, that the importance of these volume regulated channels and transporters are not restricted to the defense of cellular volume......, controlled cell death and cellular migration. Volume regulatory mechanisms has long been in focus for regulating cellular proliferation and my thesis work have been focusing on the role of Cl- channels in proliferation with specific emphasis on ICl, swell. Pharmacological blockage of the ubiquitously...

  6. Volume Regulation in Epithelia

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Hoffmann, Else Kay

    2016-01-01

    We review studies on regulatory volume decrease (RVD) and regulatory volume increase (RVI) of major ion and water transporting vertebrate epithelia. The rate of RVD and RVI is faster in cells of high osmotic permeability like amphibian gallbladder and mammalian proximal tubule as compared to...... amphibian skin and mammalian cortical collecting tubule of low and intermediate osmotic permeability. Crosstalk between entrance and exit mechanisms interferes with volume regulation both at aniso-osmotic and iso-osmotic volume perturbations. It has been proposed that cell volume regulation is an intrinsic...... function of iso-osmotic fluid transport that depends on Na+ recirculation. The causative relationship is discussed for a fluid-absorbing and a fluid-secreting epithelium of which the Na+ recirculation mechanisms have been identified. A large number of transporters and ion channels involved in cell volume...

  7. Quantitative targeting maps based on experimental investigations for a branched tube model in magnetic drug targeting

    Energy Technology Data Exchange (ETDEWEB)

    Gitter, K., E-mail: kurt.gitter@tu-dresden.de [TU Dresden, Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, 01062 Dresden (Germany); Odenbach, S. [TU Dresden, Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, 01062 Dresden (Germany)

    2011-12-15

    Magnetic drug targeting (MDT), because of its high targeting efficiency, is a promising approach for tumour treatment. Unwanted side effects are considerably reduced, since the nanoparticles are concentrated within the target region due to the influence of a magnetic field. Nevertheless, understanding the transport phenomena of nanoparticles in an artery system is still challenging. This work presents experimental results for a branched tube model. Quantitative results describe, for example, the net amount of nanoparticles that are targeted towards the chosen region due to the influence of a magnetic field. As a result of measurements, novel drug targeting maps, combining, e.g. the magnetic volume force, the position of the magnet and the net amount of targeted nanoparticles, are presented. The targeting maps are valuable for evaluation and comparison of setups and are also helpful for the design and the optimisation of a magnet system with an appropriate strength and distribution of the field gradient. The maps indicate the danger of accretion within the tube and also show the promising result of magnetic drug targeting that up to 97% of the nanoparticles were successfully targeted. - Highlights: > Quantitative targeting maps summarise a series of measurements. > Targeting maps combine quantitative data, magnetic volume forces and magnet position. > Here, up to 97% of injected particles were targeted towards the tumour region. > High concentration of injected ferrofluid brings the danger of accretion. > Low miscibility of ferrofluid by water modelling the blood flow is detected.

  8. Mean nuclear volume

    DEFF Research Database (Denmark)

    Mogensen, O.; Sørensen, Flemming Brandt; Bichel, P.;

    1999-01-01

    We evaluated the following nine parameters with respect to their prognostic value in females with endometrial cancer: four stereologic parameters [mean nuclear volume (MNV), nuclear volume fraction, nuclear index and mitotic index], the immunohistochemical expression of cancer antigen (CA125) and...

  9. Postoperative volume balance

    DEFF Research Database (Denmark)

    Frost, H; Mortensen, C.R.; Secher, N H;

    2016-01-01

    In healthy humans, stroke volume (SV) and cardiac output (CO) do not increase with expansion of the central blood volume by head-down tilt or administration of fluid. Here, we exposed 85 patients to Trendelenburg's position about one hour after surgery while cardiovascular variables were determined...

  10. Emphysema lung lobe volume reduction: effects on the ipsilateral and contralateral lobes

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Matthew S.; Kim, Hyun J.; Abtin, Fereidoun G.; Galperin-Aizenberg, Maya; Pais, Richard; Da Costa, Irene G.; Ordookhani, Arash; Chong, Daniel; Ni, Chiayi; McNitt-Gray, Michael F.; Goldin, Jonathan G. [David Geffen School of Medicine at UCLA, Center for Computer Vision and Imaging Biomarkers, Department of Radiological Sciences, Los Angeles, CA (United States); Strange, Charlie [Medical University of South Carolina, Department of Pulmonary and Critical Care Medicine, Columbia, SC (United States); Tashkin, Donald P. [David Geffen School of Medicine at UCLA, Division of Pulmonary and Critical Care Medicine, Los Angeles, CA (United States)

    2012-07-15

    To investigate volumetric and density changes in the ipsilateral and contralateral lobes following volume reduction of an emphysematous target lobe. The study included 289 subjects with heterogeneous emphysema, who underwent bronchoscopic volume reduction of the most diseased lobe with endobronchial valves and 132 untreated controls. Lobar volume and low-attenuation relative area (RA) changes post-procedure were measured from computed tomography images. Regression analysis (Spearman's rho) was performed to test the association between change in the target lobe volume and changes in volume and density variables in the other lobes. The target lobe volume at full inspiration in the treatment group had a mean reduction of -0.45 L (SE = 0.034, P < 0.0001), and was associated with volume increases in the ipsilateral lobe (rho = -0.68, P < 0.0001) and contralateral lung (rho = -0.16, P = 0.006), and overall reductions in expiratory RA (rho = 0.31, P < 0.0001) and residual volume (RV)/total lung capacity (TLC) (rho = 0.13, P = 0.03). When the volume of an emphysematous target lobe is reduced, the volume is redistributed primarily to the ipsilateral lobe, with an overall reduction. Image-based changes in lobar volumes and densities indicate that target lobe volume reduction is associated with statistically significant overall reductions in air trapping, consistent with expansion of the healthier lung. (orig.)

  11. Gated viewing for target detection and target recognition

    Science.gov (United States)

    Steinvall, Ove K.; Olsson, Hakan; Bolander, Goeran; Groenwall, Christina A.; Letalick, Dietmar

    1999-05-01

    Gated viewing using short pulse lasers and fast cameras offers many new possibilities in imaging compared with passive EO imaging. Among these we note ranging capability, large target-to-background contrast also in low visibility, good penetration capability trough obscurants and vegetation as well as through shadows in buildings, cars, etc. We also note that short wavelength laser systems have better angular resolution than long-wave infrared systems of the same aperture size. This gives an interesting potential of combined IR and laser systems for target detection and classification. Beside military applications civilian applications of gated viewing for search and rescue as well as vehicle enhanced vision and other applications are in progress. This presentation investigates the performance for gated viewing systems during different atmospheric conditions, including obscurants and gives examples of experimental data. The paper also deals with signal processing of gated viewing images for target detection. This is performed in two steps. First, image frames containing information of interest are found. In a second step those frames are investigated further to evaluate if man-made objects are present. In this step a sequence of images (video frames) are set up as a 3-D volume to incorporate spatial information. The object will then be detected using a set of quadrature filters operating on the volume.

  12. Google attention and target price run ups

    OpenAIRE

    Siganos, A.

    2013-01-01

    We explore the increase in the share prices of target firms before their merger announcements. We use a novelty Google search volume to proxy the market expectation hypothesis according to which firms with an abnormal upward change in Google searches are identified as firms with potential merger activity. We find that Google indicators can explain a larger percentage of the price increase in target firms before their mergers than the Financial Times. However even the Google proxy of the marke...

  13. Live ultrasound volume reconstruction using scout scanning

    Science.gov (United States)

    Meyer, Amelie; Lasso, Andras; Ungi, Tamas; Fichtinger, Gabor

    2015-03-01

    Ultrasound-guided interventions often necessitate scanning of deep-seated anatomical structures that may be hard to visualize. Visualization can be improved using reconstructed 3D ultrasound volumes. High-resolution 3D reconstruction of a large area during clinical interventions is challenging if the region of interest is unknown. We propose a two-stage scanning method allowing the user to perform quick low-resolution scouting followed by high-resolution live volume reconstruction. Scout scanning is accomplished by stacking 2D tracked ultrasound images into a low-resolution volume. Then, within a region of interest defined in the scout scan, live volume reconstruction can be performed by continuous scanning until sufficient image density is achieved. We implemented the workflow as a module of the open-source 3D Slicer application, within the SlicerIGT extension and building on the PLUS toolkit. Scout scanning is performed in a few seconds using 3 mm spacing to allow region of interest definition. Live reconstruction parameters are set to provide good image quality (0.5 mm spacing, hole filling enabled) and feedback is given during live scanning by regularly updated display of the reconstructed volume. Use of scout scanning may allow the physician to identify anatomical structures. Subsequent live volume reconstruction in a region of interest may assist in procedures such as targeting needle interventions or estimating brain shift during surgery.

  14. Bronchoscopic lung volume reduction

    Directory of Open Access Journals (Sweden)

    M. I. Polkey

    2006-12-01

    Full Text Available Surgical lung volume reduction can improve exercise performance and forced expiratory volume in one second in patients with emphysema. However, the procedure is associated with a 5% mortality rate and a nonresponse rate of 25%. Accordingly, interest has focused on alternative ways of reducing lung volume. Two principle approaches are used: collapse of the diseased area using blockers placed endobronchially and the creation of extrapulmonary pathways. Preliminary data from the former approach suggest that it can be successful and that the magnitude of success is related to reduction in dynamic hyperinflation.

  15. Volume rendering: application in static field conformal radiosurgery

    Science.gov (United States)

    Bourland, J. Daniel; Camp, Jon J.; Robb, Richard A.

    1992-09-01

    Lesions in the head which are large or irregularly shaped present challenges for radiosurgical treatment by linear accelerator or other radiosurgery modalities. To treat these lesions we are developing static field, conformal stereotactic radiosurgery. In this procedure seven to eleven megavoltage x-ray beams are aimed at the target volume. Each beam is designed from the beam's-eye view, and has its own unique geometry: gantry angle, table angle, and shape which conforms to the projected cross-section of the target. A difficulty with this and other 3- D treatment plans is the visualization of the treatment geometry and proposed treatment plan. Is the target volume geometrically covered by the arrangement of beams, and is the dose distribution adequate? To answer these questions we have been investigating the use of ANALYZETM volume rendering to display the target anatomy and the resultant dose distribution.

  16. Retrospective clinical study of simultaneous reduced dose in clinical target volume of radical intensity-modulated radiotherapy for treatment of stage Ⅲ non-small-cell lung cancer%CTV同步减量根治性IMRT对Ⅲ期NSCLC回顾观察

    Institute of Scientific and Technical Information of China (English)

    陈秀丽; 刘宁波; 赵路军; 姬凯; 石翔宇; 王大权; 陈曦; 王平

    2016-01-01

    Objective To evaluate the efficacy and adverse effects of radical intensity-modulated radiotherapy (IMRT) with simultaneous reduced dose in clinical target volume (CTV) for inoperable stage Ⅲ non-small cell lung cancer (NSCLC).Methods A retrospective analysis was performed on a total of 70 patients with stage Ⅲ NSCLC who were admitted to our hospital from 2010 to 2014.All patients received simultaneous reduced-dose IMRT with a prescribed dose of 60 Gy in 30 fractions or 60.2 Gy in 28 fractions for primary gross tumor volume (PGTV,expansion of gross tumor volume by 0.5 cm) and a prescribed dose of 54 Gy in 30 fractions or 50.4 Gy in 28 fractions for planning target volume (PTV).In the 70 patients,40 received neoadjuvant chemotherapy prior to radiotherapy,50 concurrent chemoradiotherapy,and 25 adjuvant chemotherapy after radiotherapy.Short-term treatment outcomes and adverse reactions were evaluated.The Kaplan-Meier method was used for survival analysis.Results The median follow-up time was 42.8 months (16.9-68.3 months).The short-term response rate (complete response (CR) plus partial response (PR))was 81.4%.The CR,PR,stable disease,and progressive disease rates were 7%(5/70),74% (52/70),13%(9/70),and 6%(4/70),respectively.In all patients,the median survival time was 26.6 months (5.2-68.3 months).The 2-year overall survival,local recurrence-free survival,and progression-free survival rates were 55%,68%,and 45%,respectively.In all patients,9%(6/70) had grade ≥3 radiation pneumonitis,4% (3/70) grade ≥ 3 oesophagitis,and 7% (5/70) grade ≥ 3 myelosuppression.Conclusions IMRT with simultaneous reduced dose in CTV is effective for stage Ⅲ NSCLC.It deserves further prospective studies with large sample sizes.%目的 观察CTV同步减量根治性IMRT对不能手术的Ⅲ期NSCLC患者的疗效及不良反应.方法 回顾分析2010-2014年本院收治的Ⅲ期NSCLC患者共70例,均为IMRT同步减量照射,PGTV(GTV外放0.5cm)剂量为60

  17. Integers annual volume 2013

    CERN Document Server

    Landman, Bruce

    2014-01-01

    ""Integers"" is a refereed online journal devoted to research in the area of combinatorial number theory. It publishes original research articles in combinatorics and number theory. This work presents all papers of the 2013 volume in book form.

  18. Cooking the volumes

    OpenAIRE

    Sparavigna, Amelia Carolina

    2012-01-01

    Cooking possesses a system of units of measurement, that includes measures of volumes based on pre-metric units. This paper discusses the cooking measures and compares their features with those of the ancient Roman measures of capacity.

  19. Environmental chemistry: Volume A

    Energy Technology Data Exchange (ETDEWEB)

    Yen, T.F.

    1999-08-01

    This is an extensive introduction to environmental chemistry for engineering and chemical professionals. The contents of Volume A include a brief review of basic chemistry prior to coverage of litho, atmo, hydro, pedo, and biospheres.

  20. New volume and inverse volume operators for loop quantum gravity

    OpenAIRE

    Yang, Jinsong; Ma, Yongge

    2016-01-01

    A new alternative volume operator is constructed for loop quantum gravity by using the so-called co-triad operators as building blocks. It is shown that the new volume operator shares the same qualitative properties with the standard volume operator. Moreover, a new alternative inverse volume operator is also constructed in the light of the construction of the alternative volume operator, which is possessed of the same qualitative properties as those of the alternative volume operator. The ne...

  1. Towards the amplituhedron volume

    OpenAIRE

    Ferro, Livia; Lukowski, Tomasz; Orta, Andrea; Parisi, Matteo

    2016-01-01

    It has been recently conjectured that scattering amplitudes in planar N = 4 $$ \\mathcal{N}=4 $$ super Yang-Mills are given by the volume of the (dual) amplituhedron. In this paper we show some interesting connections between the tree-level amplituhedron and a special class of differential equations. In particular we demonstrate how the amplituhedron volume for NMHV amplitudes is determined by these differential equations. The new formulation allows for a straightforward geometric description,...

  2. Volume anomaly in ferrimagnetism

    OpenAIRE

    Pascard, H.; Globus, A.

    1981-01-01

    The volume anomaly ΔV/V due to the magnetic energy corresponding to the exchange interactions is experimentally determined for YIG. The experimental values (from 77 K to Tc) agree with the values deduced from the theoretical expression based on the Néel's theories of volume anomaly and of ferrimagnetism. These results are compared with those obtained by other authors on ferromagnetic and antiferromagnetic materials with localized magnetic moments : a reduced curve is obtained.

  3. Volume holographic memory

    OpenAIRE

    Cornelia Denz; K. O. Muller; F. Visinka; Berger, G; T. Tschudi

    2000-01-01

    Volume holography represents a promising alternative to existing storage technologies. Its parallel data storage leads to high capacities combined with short access times and high transfer rates. The design and realization of a compact volume holographic storage demonstrator is presented. The technique of phase-coded multiplexing implemented to superimpose many data pages in a single location enables to store up to 480 holograms per storage location without any moving parts. Results of analog...

  4. Reachable volume RRT

    KAUST Repository

    McMahon, Troy

    2015-05-01

    © 2015 IEEE. Reachable volumes are a new technique that allows one to efficiently restrict sampling to feasible/reachable regions of the planning space even for high degree of freedom and highly constrained problems. However, they have so far only been applied to graph-based sampling-based planners. In this paper we develop the methodology to apply reachable volumes to tree-based planners such as Rapidly-Exploring Random Trees (RRTs). In particular, we propose a reachable volume RRT called RVRRT that can solve high degree of freedom problems and problems with constraints. To do so, we develop a reachable volume stepping function, a reachable volume expand function, and a distance metric based on these operations. We also present a reachable volume local planner to ensure that local paths satisfy constraints for methods such as PRMs. We show experimentally that RVRRTs can solve constrained problems with as many as 64 degrees of freedom and unconstrained problems with as many as 134 degrees of freedom. RVRRTs can solve problems more efficiently than existing methods, requiring fewer nodes and collision detection calls. We also show that it is capable of solving difficult problems that existing methods cannot.

  5. Features of photonuclear radionuclide production in the thick targets

    International Nuclear Information System (INIS)

    One of the basic requirements for the production technology of radionuclides is to provide a high specific activity of the target nuclide as well as its full activity in target. Traditionally this problem is solved by using a large volume of photonuclear targets with subsequent by radiochemical separation target nuclide. Modeling and experimental study of the spatial distribution of the activity carried out in this work for the various targets. Optimal parameters of irradiation to achieve the maximum yield of isotopes Mo99(Tc99m) and Cu67 in targets from molybdenum and zinc of natural composition have been found.

  6. WYSIWYG (What You See is What You Get) volume visualization.

    Science.gov (United States)

    Guo, Hanqi; Mao, Ningyu; Yuan, Xiaoru

    2011-12-01

    In this paper, we propose a volume visualization system that accepts direct manipulation through a sketch-based What You See Is What You Get (WYSIWYG) approach. Similar to the operations in painting applications for 2D images, in our system, a full set of tools have been developed to enable direct volume rendering manipulation of color, transparency, contrast, brightness, and other optical properties by brushing a few strokes on top of the rendered volume image. To be able to smartly identify the targeted features of the volume, our system matches the sparse sketching input with the clustered features both in image space and volume space. To achieve interactivity, both special algorithms to accelerate the input identification and feature matching have been developed and implemented in our system. Without resorting to tuning transfer function parameters, our proposed system accepts sparse stroke inputs and provides users with intuitive, flexible and effective interaction during volume data exploration and visualization. PMID:22034329

  7. Target Awareness: Lupus

    Science.gov (United States)

    ... Target Awareness: Lupus Jan. 15, 2009 Target Awareness: Lupus Target Awareness: Lupus provides a brief overview of ... Email Print Tags for this Story treatments symptoms Lupus FAQ What is lupus? What are the common ...

  8. Target Awareness: Lupus

    Medline Plus

    Full Text Available ... Target Awareness: Lupus Jan. 15, 2009 Target Awareness: Lupus Target Awareness: Lupus provides a brief overview of ... Email Print Tags for this Story treatments symptoms Lupus FAQ What is lupus? What are the common ...

  9. Target factory in perspective

    International Nuclear Information System (INIS)

    A target factory diagram has been constructed for an analysis of the shell coating process system in relation to target production. The number of deposition units needed to achieve the coating requirements will be a major target production operating cost

  10. Nuclear maintenance work volume model

    International Nuclear Information System (INIS)

    This presentation will cover a work volume model, detailing what contributes to a maintenance backlog and demonstrate the impact of these contributing factors on it's reduction. In our quest to achieve sustainable nuclear excellence, we have engaged in many debates over our degree of success in reducing the maintenance backlog at Ontario Power Generation plants. The backlog is a volume of work and a simplified analogy would be to consider it as the water level in a tank. The inflow would be the new work requests/minor work orders not completed by the Fix It Now Team, and the outflow would be the completed work orders. The equilibrium in the tank would be the result of the incoming rate of new work versus the rate of outgoing completed work. We can accommodate increasing levels for short durations, but our success depends on our ability to manage the process and achieving timely long term reduction in backlog. Although everyone seemed to have an understanding for the type of change required, it was difficult to quantify the optimum combination. Increasing the work force always seems to be an obvious choice, along with productivity improvements but there must be careful consideration given to the preventative maintenance program and resource allocation such as Support Staff, Fix It Now Team, Outages, Projects, etc. Various other factors impacting on our work rates would include training loads, sick leave and overtime. A need was identified for some analytical tool that would illustrate if our goals were attainable with our present course of action, and demonstrate what changes needed to be implemented in order to be successful. We developed a model consisting of an Excel spreadsheet that trends the backlog for each maintenance workgroup. The user populates the model with specific historical data for plant resource profiles and work execution. The program generates two sets of charts for each maintenance groups, one for actual data and another for target data. The

  11. Volumes of chain links

    CERN Document Server

    Kaiser, James; Rollins, Clint

    2011-01-01

    Agol has conjectured that minimally twisted n-chain links are the smallest volume hyperbolic manifolds with n cusps, for n at most 10. In his thesis, Venzke mentions that these cannot be smallest volume for n at least 11, but does not provide a proof. In this paper, we give a proof of Venzke's statement. The proof for n at least 60 is completely rigorous. The proof for n between 11 and 59 uses a computer calculation, and can be made rigorous for manifolds of small enough complexity, using methods of Moser and Milley. Finally, we prove that the n-chain link with 2m or 2m+1 half-twists cannot be the minimal volume hyperbolic manifold with n cusps, provided n is at least 60 or |m| is at least 8, and we give computational data indicating this remains true for smaller n and |m|.

  12. Aperiodic Volume Optics

    Science.gov (United States)

    Gerke, Tim D.

    Presented in this thesis is an investigation into aperiodic volume optical devices. The three main topics of research and discussion are the aperiodic volume optical devices that we call computer-generated volume holograms (CGVH), defects within periodic 3D photonic crystals, and non-periodic, but ordered 3D quasicrystals. The first of these devices, CGVHs, are designed and investigated numerically and experimentally. We study the performance of multi-layered amplitude computer-generated volume holograms in terms of efficiency and angular/frequency selectivity. Simulation results show that such aperiodic devices can increase diffraction efficiency relative to periodic amplitude volume holograms while maintaining angular and wavelength selectivity. CGVHs are also designed as voxelated volumes using a new projection optimization algorithm. They are investigated using a volumetric diffraction simulation and a standard 3D beam propagation technique as well as experimentally. Both simulation and experiment verify that the structures function according to their design. These represent the first diffractive structures that have the capacity for generating arbitrary transmission and reflection wave fronts and that provide the ability for multiplexing arbitrary functionality given different illumination conditions. Also investigated and discussed in this thesis are 3D photonic crystals and quasicrystals. We demonstrate that these devices can be fabricated using a femtosecond laser direct writing system that is particularly appropriate for fabrication of such arbitrary 3D structures. We also show that these devices can provide 3D partial bandgaps which could become complete bandgaps if fabricated using high index materials or by coating lower index materials with high index metals. Our fabrication method is particularly suited to the fabrication of engineered defects within the periodic or quasi-periodic systems. We demonstrate the potential for fabricating defects within

  13. Volume holographic memory

    Directory of Open Access Journals (Sweden)

    Cornelia Denz

    2000-05-01

    Full Text Available Volume holography represents a promising alternative to existing storage technologies. Its parallel data storage leads to high capacities combined with short access times and high transfer rates. The design and realization of a compact volume holographic storage demonstrator is presented. The technique of phase-coded multiplexing implemented to superimpose many data pages in a single location enables to store up to 480 holograms per storage location without any moving parts. Results of analog and digital data storage are shown and real time optical image processing is demonstrated.

  14. Variance of volume estimators

    Czech Academy of Sciences Publication Activity Database

    Janáček, Jiří

    Jena : Friedrich-Schiller-Universität, 2007. s. 23-23. [Workshop on Stochastic Geometry, Stereology and Image Analysis /14./. 23.09.2007-28.09.2007, Neudietendorf] R&D Projects: GA AV ČR(CZ) IAA100110502 Institutional research plan: CEZ:AV0Z50110509 Keywords : spr2 * stereology * volume * variance Subject RIV: EA - Cell Biology

  15. Volume measuring system

    Science.gov (United States)

    Oele, J. S.

    1975-01-01

    Chamber is designed to be airtight; it includes face mask for person to breathe outside air so that he does not disturb chamber environment. Chamber includes piston to vary air volume inside. Also included are two microphone transducers which record pressure information inside chamber.

  16. Overview of the Volume

    Science.gov (United States)

    Dennis, Brian R.; Emslie, A. G.; Hudson, H. S.

    2011-01-01

    In this introductory chapter, we provide a brief summary of the successes and remaining challenges in understanding the solar flare phenomenon and its attendant implications for particle acceleration mechanisms in astrophysical plasmas. We also provide a brief overview of the contents of the other chapters in this volume, with particular reference to the well-observed flare of 2002 July 23.

  17. 4D-CT-based plan target volume (PTV)definition compared with conventional PTV definition using general margin in radiotherapy for lung cancer%肺癌放疗中四维CT技术与传统方法勾画靶区计划比较

    Institute of Scientific and Technical Information of China (English)

    鞠潇; 李明辉; 周宗玫; 张可; 韩伟; 符贵山; 曹莹; 王绿化

    2014-01-01

    目的 比较肺癌放疗中四维CT(4D-CT)技术与传统方法勾画计划靶区体积(PTV)的治疗计划差异.方法 选择10例肺癌患者,均行4D-CT及普通螺旋CT定位扫描,分别采用4D-CT和常规经验外扩PTV方法确定计划靶区(PTV4D和PTWconv)和制定治疗计划(Plan4D和Planconv),测量大体肿瘤体积(GTV)质心在三维方向上随呼吸运动的位移,计算三维空间位移向量| (v)|.比较4D-CT技术与传统方法所得PTV、双肺平均受量(MLD)、双肺V5(Vx表示接受xGy照射的百分体积)、双肺V1o、双肺V15、双肺V20、心脏平均受量(MHD)、心脏V30、心脏V40、99%靶体积受照剂量(D99)和95%靶体积受照剂量(D95)的变化,并分析其与三维空间位移向量|(v)|的关系.结果 10例患者中,8例患者PTV4D< PTVconv,减少(13.0±8.0)%(P=0.018),2例患者PTV4D> PTVconv.GTV质心三维空间位移向量|(v)|为(0.78±0.72)cm.MLD4D较MLDconv减少(8.6±9.9)%(P=0.037).Plan4D的双肺V5、V10、V15、V20分别较Planconv减少(7.2±10.5)%、(5.5±8.9)%、(6.5±8.4)%和(5.7±7.4)%(均P<0.05).10例患者Plan4D和Planconv的D99分别为(56.68±1.82) Gy和(56.12±2.23) Gy(P=0.092),Plan4D和Planconv的D95分别为(60.04±0.46) Gy和(59.86±0.51) Gy (P =0.026).PTV4D/PTVconv与三维空间位移向量| (v) |呈正相关关系(P =0.008),D994D/D99conv与| (v) |呈负相关关系(P=0.002),D994D/D99conv、(MLDconv-MLD4D)/MLDconv、双肺(V5conv-V54D)/V5conv、双肺(V10conv-V104D)/V10conv、(MHDconv-MHD4D)/MHDconv、心脏(V30conv-V304D)/V30convv与PTV4D/PTVconv呈负相关关系(均P<0.05).结论 4D-CT可准确评价肺部肿瘤随呼吸运动的位移,应用4D-CT数据定义靶区及制定计划,可缩小肿瘤动度小的PTV,提高靶区内剂量,减少正常组织受量,对于肿瘤动度大的患者,可在不明显增加正常组织受量的前提下,避免靶区遗漏.%Objective To investigate the dosimetric benefit of 4D-CT in the planning target volume (PTV) definition

  18. Prostate cancer: Doses and volumes of radiotherapy; Cancer de prostate: doses et volumes cibles

    Energy Technology Data Exchange (ETDEWEB)

    Hennequin, C.; Rivera, S.; Quero, L. [Service de cancerologie-radiotherapie, hopital Saint-Louis, AP-HP, 75 - Paris (France); Latorzeff, I. [Service de radiotherapie, groupe Oncorad-Garonne, clinique Pasteur, -l' Atrium-, 31 - Toulouse (France)

    2010-10-15

    Radiotherapy is nowadays a major therapeutic option in prostate cancer. Technological improvements allowed dose escalation without increasing late toxicity. Some randomized trials have shown that dose escalation decreases the biochemical failure rate, without any benefit in survival with the present follow-up. However, some studies indicate that the distant metastases rate is also decreased. Most of these studies have been done without hormonal treatment, and the role of dose escalation in case of long-term androgen deprivation is unknown. The target volume encompassed the whole gland: however, complete or partial focal treatment of the prostate can be done with sophisticated IMRT technique and must be evaluated. Proximal part of the seminal vesicles must be included in the target volumes. The role of nodal irradiation is another debate, but it could be logically proposed for the unfavourable group. (authors)

  19. Thermal hydraulics of lead-bismuth target of 0.6 MW target complex

    International Nuclear Information System (INIS)

    The experimental results of the work on the project of target complex - demonstration installation for justification of subcritical accelerator-control system with liquid metal target are given. The investigation program consisted of determination of target pressure drop along the flow path length from suction to outlet nozzles and dependence of injection losses on distance between separating membrane and shaped grid; development of technical design report on coolant flow azimuthal distribution balancing near separating membrane; generation of coolant flow rate profiles in volume energy release zone; investigation of intensity and velocity pulsation spectra near separating membrane

  20. Effective neutron targets

    International Nuclear Information System (INIS)

    Because of the lack of a free neutron target, deuterium targets have been used extensively in studying the neutron structure. The unique spin structure of the 3He ground state wave function and the recent developments in laser technologies made polarized 3He targets widely used in many experiments from neutron electromagnetic form factor studies to nucleon spin structure function measurements at all major electron accelerator facilities. In this talk, the current status of the polarized 3He targets will be reviewed. The author will focus on neutron electromagnetic form factor studies using polarized 3He targets. The polarized nucleon spin structure function measurements using polarized 3He targets will also be discussed

  1. Target Visualization at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Potter, Daniel Abraham [Univ. of California, Davis, CA (United States)

    2011-01-01

    As the National Ignition Facility continues its campaign to achieve ignition, new methods and tools will be required to measure the quality of the targets used to achieve this goal. Techniques have been developed to measure target surface features using a phase-shifting diffraction interferometer and Leica Microsystems confocal microscope. Using these techniques we are able to produce a detailed view of the shell surface, which in turn allows us to refine target manufacturing and cleaning processes. However, the volume of data produced limits the methods by which this data can be effectively viewed by a user. This paper introduces an image-based visualization system for data exploration of target shells at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. It aims to combine multiple image sets into a single visualization to provide a method of navigating the data in ways that are not possible with existing tools.

  2. Molecular Targets for Targeted Radionuclide Therapy

    International Nuclear Information System (INIS)

    Molecular targeted radionuclide cancer therapy is becoming of increasing importance, especially for disseminated diseases. Systemic chemotherapies often lack selectivity while targeted radionuclide therapy has important advantages as the radioactive cytotoxic unit of the targeting vector is specifically directed to the cancer, sparing normal tissues. The principle strategy to improve cancer selectivity is to couple therapeutic agents to tumour-targeting vectors. In targeted radionuclide therapy (TRT), the cytotoxic portion of the conjugates normally contains a therapeutic radiometal immobilised by a bifunctional chelator. The aim is therefore to use as ligand-targeted therapeutics vectors coupled to Auger-, alpha- and/or beta-emitting radionuclides. An advantage of using radiation instead of chemotherapeutics as the cytotoxic agent is the so called 'crossfire effect'. This allows sterilisation of tumour cells that are not directly targeted due to heterogeneity in target molecule expression or inhomogeneous vector delivery. However, before the targeting ligands can be selected, the target molecule on the tumour has to be selected. It should be uniquely expressed, or at least highly overexpressed, on or in the target cells relative to normal tissues. The target should be easily accessible for ligand delivery and should not be shed or down- regulated after ligand binding. An important property of a receptor (or antigen) is its potential to be internalized upon binding of the ligand. This provides an active uptake mechanism and allows the therapeutic agent to be trapped within the tumour cells. Molecular targets of current interest include: Receptors: G-protein coupled receptors are overexpressed on many major human tumours. The prototype of these receptors are somatostatin receptors which show very high density in neuroendocrine tumours, but there are many other most interesting receptors to be applied for TRT. The targeting ligands for these receptors are

  3. Mixed volumes of hypersimplices

    OpenAIRE

    Liu, Gaku

    2014-01-01

    In this paper we consider mixed volumes of combinations of hypersimplices. These numbers, called "mixed Eulerian numbers", were first considered by A. Postnikov and were shown to satisfy many properties related to Eulerian numbers, Catalan numbers, binomial coefficients, etc. We give a general combinatorial interpretation for mixed Eulerian numbers and prove the above properties combinatorially. In particular, we show that each mixed Eulerian number enumerates a certain set of permutations in...

  4. Backward volume contraction for endomorphisms with eventual volume expansion

    OpenAIRE

    Pinheiro, Vilton; Castro, Armando; Alves, J. F.

    2009-01-01

    We consider smooth maps on compact Riemannian manifolds. We prove that under some mild condition of eventual volume expansion Lebesgue almost everywhere we have uniform backward volume contraction on every pre-orbit for Lebesgue almost every point.

  5. Anisotropic Ambient Volume Shading.

    Science.gov (United States)

    Ament, Marco; Dachsbacher, Carsten

    2016-01-01

    We present a novel method to compute anisotropic shading for direct volume rendering to improve the perception of the orientation and shape of surface-like structures. We determine the scale-aware anisotropy of a shading point by analyzing its ambient region. We sample adjacent points with similar scalar values to perform a principal component analysis by computing the eigenvectors and eigenvalues of the covariance matrix. In particular, we estimate the tangent directions, which serve as the tangent frame for anisotropic bidirectional reflectance distribution functions. Moreover, we exploit the ratio of the eigenvalues to measure the magnitude of the anisotropy at each shading point. Altogether, this allows us to model a data-driven, smooth transition from isotropic to strongly anisotropic volume shading. In this way, the shape of volumetric features can be enhanced significantly by aligning specular highlights along the principal direction of anisotropy. Our algorithm is independent of the transfer function, which allows us to compute all shading parameters once and store them with the data set. We integrated our method in a GPU-based volume renderer, which offers interactive control of the transfer function, light source positions, and viewpoint. Our results demonstrate the benefit of anisotropic shading for visualization to achieve data-driven local illumination for improved perception compared to isotropic shading. PMID:26529745

  6. Information architecture. Volume 4: Vision

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The Vision document marks the transition from definition to implementation of the Department of Energy (DOE) Information Architecture Program. A description of the possibilities for the future, supported by actual experience with a process model and tool set, points toward implementation options. The directions for future information technology investments are discussed. Practical examples of how technology answers the business and information needs of the organization through coordinated and meshed data, applications, and technology architectures are related. This document is the fourth and final volume in the planned series for defining and exhibiting the DOE information architecture. The targeted scope of this document includes DOE Program Offices, field sites, contractor-operated facilities, and laboratories. This document paints a picture of how, over the next 7 years, technology may be implemented, dramatically improving the ways business is conducted at DOE. While technology is mentioned throughout this document, the vision is not about technology. The vision concerns the transition afforded by technology and the process steps to be completed to ensure alignment with business needs. This goal can be met if those directing the changing business and mission-support processes understand the capabilities afforded by architectural processes.

  7. Price level targeting

    OpenAIRE

    Shukayev, Malik; Ueberfeldt, Alexander

    2010-01-01

    Various papers have suggested that Price-Level targeting is a welfare improving policy relative to Inflation targeting. From a practical standpoint, this raises an important yet unanswered question: What is the optimal price index to target? This paper derives the optimal price level targeting index defined over the eight main components of the Consumer Price Index. It finds that such an index places a heavier weight, relative to the expenditure weight, on sectors with slow price adjustments....

  8. Multilayer polymer microspot targets

    International Nuclear Information System (INIS)

    Last year the authors reported on the development of a seeded microspot x-ray diagnostic target. This target consisted of a 300-μm-diam, 2-μm-thick disk of silicon or sulfur-seeded hydrocarbon polymer nested tightly in a hole in a 2-μm-thick film of pure hydrocarbon polymer. This year they extended our work on the microspot target, fully encapsulating the microspot in what they call the multilayer polymer microspot target

  9. Target Price Accuracy

    OpenAIRE

    Alexander G. Kerl

    2011-01-01

    This study analyzes the accuracy of forecasted target prices within analysts’ reports. We compute a measure for target price forecast accuracy that evaluates the ability of analysts to exactly forecast the ex-ante (unknown) 12-month stock price. Furthermore, we determine factors that explain this accuracy. Target price accuracy is negatively related to analyst-specific optimism and stock-specific risk (measured by volatility and price-to-book ratio). However, target price accuracy is positive...

  10. The Targeting of Advertising

    OpenAIRE

    Ganesh Iyer; David Soberman; J. Miguel Villas-Boas

    2005-01-01

    An important question that firms face in advertising is developing effective media strategy. Major improvements in the quality of consumer information and the growth of targeted media vehicles allow firms to precisely target advertising to consumer segments within a market. This paper examines advertising strategy when competing firms can target advertising to different groups of consumers within a market. With targeted advertising, we find that firms advertise more to consumers who have a st...

  11. TARGET COSTING FUNCTIONS

    OpenAIRE

    Dimi OFILEANU

    2015-01-01

    This article aims to highlight the concept of Target Costing. Based on the characteristics of Target Costing, identified in specialized literature, the article presents its main advantages and disadvantages. Also, a comparison is being made between Target Cost and Traditional Cost (in its traditional form, the cost represents an independent variable on the basis of which the sell price is established; and in the Target Cost form the cost represents a dependent variable which is determined on ...

  12. An actionable climate target

    Science.gov (United States)

    Geden, Oliver

    2016-05-01

    The Paris Agreement introduced three mitigation targets. In the future, the main focus should not be on temperature targets such as 2 or 1.5 °C, but on the target with the greatest potential to effectively guide policy: net zero emissions.

  13. ENT interstitial pulse dose rate curietherapy: using dose-volume histograms; Curietherapie interstitielle de debit pulse ORL: utilisation des histogrammes dose-volume

    Energy Technology Data Exchange (ETDEWEB)

    Le Bourhis, J.; Moreira, J.F.; Chassin, V.; Donnarieix, D.; Lapeyre, M. [Centre jean-Perrin, Clermont-Ferrand (France)

    2011-10-15

    The authors report a study which aimed at analysing dosimetric results on different dose-volume histograms obtained during a three-dimensional pulse dose rate curie-therapy. Six patients have been treated by post-operative curie-therapy of a tongue cancer. Using dose-volume histograms allows the dose delivered to organs at risk and to the target volume to be controlled. Short communication

  14. Three architectures for volume rendering

    OpenAIRE

    Hesser, Jürgen; Männer, Reinhard; Knittel, Günter; Straßer, Wolfgang; Pfister, Hanspeter; Kaufman, Arie

    1995-01-01

    Volume rendering is a key technique in scientific visualization that lends itself to significant exploitable parallelism. The high computational demands of real-time volume rendering and continued technological advances in the area of VLSI give impetus to the development of special-purpose volume rendering architectures. This paper presents and characterizes three recently developed volume rendering engines which are based on the ray-casting method. A taxonomy of the algorithmic variants of r...

  15. Calculus Students' Understanding of Volume

    Science.gov (United States)

    Dorko, Allison; Speer, Natasha M.

    2013-01-01

    Researchers have documented difficulties that elementary school students have in understanding volume. Despite its importance in higher mathematics, we know little about college students' understanding of volume. This study investigated calculus students' understanding of volume. Clinical interview transcripts and written responses to volume…

  16. COMPASS polarized target for Drell-Yan

    CERN Document Server

    Pešek, M

    2014-01-01

    In the COMPASS Drell–Yan experiment the pion beam with momen tum of 190 GeV/ c and in- tensity up to 10 8 pions/s will interact with transversely polarized proton t arget producing muon pair via Drell–Yan process. The solid-state NH 3 will be polarized by dynamic nuclear polar- ization. Maximum polarization reached during data taking i s expected to be up to 90%. The non-interacting beam and other particles produced inside t he target will be stopped in the hadron absorber after the target. Two target cells, sepparated by a 20 cm gap in between, each 55 cm long and 4 cm in diameter give the target material volume about 691 cm 3 . The target platform needs to be moved by 2.3 m in upstream dire ction from the position used in previous experiments in order to accomodate the absorber. D uring the beam time higher radiation is expected in the area of the control room. Thus a new target r emote control system is needed. The target magnet is undergoing a substantial upgrade. Drell–Yan data taking is expected t...

  17. New volume and inverse volume operators for loop quantum gravity

    CERN Document Server

    Yang, Jinsong

    2016-01-01

    A new alternative volume operator is constructed for loop quantum gravity by using the so-called co-triad operators as building blocks. It is shown that the new volume operator shares the same qualitative properties with the standard volume operator. Moreover, a new alternative inverse volume operator is also constructed in the light of the construction of the alternative volume operator, which is possessed of the same qualitative properties as those of the alternative volume operator. The new inverse volume operator can be employed to construct the Hamiltonian operator of matter fields, which may lead to an anomaly-free on shell quantum constraint algebra without any special restriction on the regularization procedure for gravity coupled to matter fields.

  18. New volume and inverse volume operators for loop quantum gravity

    Science.gov (United States)

    Yang, Jinsong; Ma, Yongge

    2016-08-01

    A new alternative volume operator is constructed for loop quantum gravity by using the so-called cotriad operators as building blocks. It is shown that the new volume operator shares the same qualitative properties with the standard volume operator. Moreover, a new alternative inverse volume operator is also constructed in the light of the construction of the alternative volume operator, which is possessed of the same qualitative properties as those of the alternative volume operator. The new inverse volume operator can be employed to construct the Hamiltonian operator of matter fields, which may lead to an anomaly-free on-shell quantum constraint algebra without any special restriction on the regularization procedure for gravity coupled to matter fields.

  19. Targeted cancer therapies

    Institute of Scientific and Technical Information of China (English)

    Li Yan; Neal Rosen; Carlos Arteaga

    2011-01-01

    With unprecedented understanding of molecular events underlying human cancer in this genomic era, a large number of drugs specifically targeting hypothesized oncogenic drivers to which tumors are potentially addicted to have been developed and continue to be developed. These targeted cancer therapies are being actively tested in clinical trials with mixed successes. This editorial provides an overview on successful targeted cancer drugs on the market and those drugs that are in late clinical development stages. Importantly, the article lays out main challenges in developing molecular targeted therapies and potential path forward to overcome these challenges, as well as opportunities for China in this new era of targeted agents. The editorial serves as an introduction to the Targeted Cancer Therapies serias that will review in depth of major pathways and drugs targeting these pathways to be published in the coming issues of the Chinese Journal of Cancer.

  20. Polarized targets and beams

    International Nuclear Information System (INIS)

    First the experimental situation of the single-pion photoproduction and the photodisintegration of the deuteron is briefly discussed. Then a description of the Bonn polarization facilities is given. The point of main effort is put on the polarized target which plays a vital role in the program. A facility for photon induced double polarization experiments at ELSA will be presented in section 4. Properties of a tensor polarized deuteron target are discussed in section 5. The development in the field of polarized targets, especially on new target materials, enables a new generation of polarized target experiments with (polarized) electrons. Some comments on the use of a polarized target in combination with electron beams will be discussed in section 6. Electron deuteron scattering from a tensor polarized deuteron target is considered and compared with other experimental possibilities. (orig./HSI)

  1. Radwaste '86: proceedings volume

    International Nuclear Information System (INIS)

    The volume contains all the papers presented at the above Conference, which was held in Cape Town, South Africa from 7 to 12 September 1986. A total of 55 contributions cover the full spectrum of the theme of the Conference, which was subdivided into four sessions. Conditioning, treatment and management of radioactive waste: 12 papers reporting on experiences in various countries, as well as specialist topics such as the extraction of radioactive contaminants from reactor pool water. Containment, safe handling and long-term integrity of ILLW packages: 2 papers dealing with cask design. Transport and storage of radwaste and spent fuel: 7 papers ranging from broad overviews to specific operations in different parts of the world. Radioactive waste disposal and environmental impact: 32 papers covering topics from site selection, design and operation, to modelling and monitoring studies. South Africa's Vaalputs radioactive waste disposal facility is comprehensively described. The volume is a useful reference for anyone interested in the disposal of radioactive waste, especially in arid environments, as well as its treatment and management prior to disposal, and will appeal to a wide range of disciplines including engineers, geologists, geophysicists, life scientists and environmentalists. Of particular interest would be the intensive studies undertaken in South Africa prior to the establishment of a radioactive waste repository in that country

  2. Environmental report 1995. Volume 2

    International Nuclear Information System (INIS)

    This is Volume 2 of the Lawrence Livermore National Laboratory's (LLNL's) annual Environmental Report 1995. This volume is intended to support summary data from Volume 1 and is essentially a detailed data report that provides additional data points, where applicable. Some summary data are also included in Volume 2, and more detailed accounts are given of sample collection and analytical methods. Volume 2 includes information in eight chapters on monitoring of air, air effluent, sewage, surface water, ground water, soil and sediment, vegetation and foodstuff, and environmental radiation, as well as three chapters on ground water protection, compliance self-monitoring and quality assurance

  3. Flayer target acceleration and energy transfer at its collision with massive targets

    International Nuclear Information System (INIS)

    Investigations of efficiency of macroparticle acceleration and crater creation processes for the two wavelengths of the PALS (Prague Asterix Laser System) facility laser beam: λ1=1.315 μm and λ3=0.438 μm, and two types of targets made of Al: single massive target and double target consisting of a foil (thickness of 6 and 11 μm) placed before the massive target at the distance of 200-500 μm are presented. Targets were irradiated by the iodine laser beam: EL=120-240 J, the focal spot diameter of 250 μm, and the pulse duration of 0.4 ns. Velocities of the accelerated macroparticles as well as electron density distributions of plasma stream were determined by means of a 3-frame interferometry. Shape and volume of craters were obtained employing crater replica technology and microscopy measurement. Experimental results were analyzed and interpreted by means of two-dimensional theoretical and numerical simulations. Energy transfer as well as two- dimensional shock wave generation and crater formation at the collision of laser-driven macroparticle with massive target have been described. The values of laser energy absorption coefficient, ablation loading efficiency and efficiency of energy transfer at the laser-driven macroparticle impact have been obtained at the different wavelength of laser radiation by crater volume measurement data. (author)

  4. Viability Assessment Volume 1

    International Nuclear Information System (INIS)

    Since May 1996, under its draft Civilian Radioactive Waste Management Program Plan (DOE 1996), DOE has been carrying out a 5-year program of work to support the decision in 2001 by the Secretary of Energy on whether or not to recommend the site to the President. Part of this program was to address major unresolved technical issues and to complete an assessment of the viability of the Yucca Mountain site by 1998. Affirming the DOE plans, Congress directed DOE in the 1997 Energy and Water Development Appropriations Act to provide a viability assessment of the Yucca Mountain site to Congress and the President. This Viability Assessment (VA) document is the DOE report to Congress and the President. They are expected to use the VA to make an informed decision about program direction and funding. Drawing on 15 years of scientific investigation and design work at Yucca Mountain, the VA summarizes a large technical basis of field investigations, laboratory tests, models, analyses, and engineering, described in cited references. The VA identifies the major uncertainties relevant to the technical defensibility of DOE analyses and designs, the DOE approach to managing these uncertainties, and the status of work toward the site recommendation and LA. The VA also identifies DOE plans for the remaining work, and the estimated costs of completing an LA and constructing and operating a repository. The attention to uncertainties is important because DOE must evaluate how the repository will perform during the next 10,000 years or longer. Uncertainties exist because of variability in the natural (geologic and hydrologic) systems at Yucca Mountain and because of imperfect scientific understanding of the natural processes that might affect the repository system. This is Volume 1 and it covers, Introduction and Site Characteristics, includes a high-level summary of the results of the VA and some additional background information. (The overview is bound separately.) Section 1 of Volume

  5. GWAS and drug targets

    OpenAIRE

    Cao, Chen; Moult, John

    2014-01-01

    Background Genome wide association studies (GWAS) have revealed a large number of links between genome variation and complex disease. Among other benefits, it is expected that these insights will lead to new therapeutic strategies, particularly the identification of new drug targets. In this paper, we evaluate the power of GWAS studies to find drug targets by examining how many existing drug targets have been directly 'rediscovered' by this technique, and the extent to which GWAS results may ...

  6. Inertial Confinement fusion targets

    Science.gov (United States)

    Hendricks, C. D.

    1982-01-01

    Inertial confinement fusion (ICF) targets are made as simple flat discs, as hollow shells or as complicated multilayer structures. Many techniques were devised for producing the targets. Glass and metal shells are made by using drop and bubble techniques. Solid hydrogen shells are also produced by adapting old methods to the solution of modern problems. Some of these techniques, problems, and solutions are discussed. In addition, the applications of many of the techniques to fabrication of ICF targets is presented.

  7. The ISOLDE target robots

    CERN Multimedia

    Maximilein Brice

    2002-01-01

    ISOLDE targets need to be changed frequently, around 80 times per year. The high radiation levels do not permit this to be done by human hands and the target changes are effected by 2 industrial robots (picture _01). On the left, in the distance, the front-end of the GPS (General Purpose Separator) is seen, while the HRS (High Resolution Separator) is at the right. Also seen are the doors to the irradiated-target storage.

  8. Moving Target Defense

    CERN Document Server

    Jajodia, Sushil; Swarup, Vipin; Wang, Cliff; Wang, X Sean

    2011-01-01

    Moving Target Defense: Creating Asymmetric Uncertainty for Cyber Threats was developed by a group of leading researchers. It describes the fundamental challenges facing the research community and identifies new promising solution paths. Moving Target Defense which is motivated by the asymmetric costs borne by cyber defenders takes an advantage afforded to attackers and reverses it to advantage defenders. Moving Target Defense is enabled by technical trends in recent years, including virtualization and workload migration on commodity systems, widespread and redundant network connectivity, instr

  9. Target Window Reliability

    Energy Technology Data Exchange (ETDEWEB)

    Woloshun, Keith Albert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-02-11

    The target window design implemented and tested in experiments at ANL have performed without failure for the available beam of 6 mm FWHM on a 12 mm diameter target. However, scaling that design to a 25 mm diameter target size for a 12 mm FWHM beam has proven problematic. Combined thermal and mechanical (pressure induced) stresses and strains are too high to maintain the small coolant gaps and provide adequate fatigue lifetime.

  10. Generalized Partial Volume

    DEFF Research Database (Denmark)

    Darkner, Sune; Sporring, Jon

    2011-01-01

    Mutual Information (MI) and normalized mutual information (NMI) are popular choices as similarity measure for multimodal image registration. Presently, one of two approaches is often used for estimating these measures: The Parzen Window (PW) and the Generalized Partial Volume (GPV). Their...... theoretical relation has so far been unexplored. We present the direct connection between PW and GPV for NMI in the case of rigid and non-rigid image registration. Through step-by-step derivations of PW and GPV we clarify the difference and show that GPV is algorithmically inferior to PW from a model point of...... view as well as w.r.t. computational complexity. Finally, we present algorithms for both approaches for NMI which is comparable in speed to Sum of Squared Differences (SSD), and we illustrate the differences between PW and GPV on a number of registration examples....

  11. Volume 6, Issue 1

    Directory of Open Access Journals (Sweden)

    Karen Nelson

    2015-03-01

    Full Text Available The International Journal of the First Year in Higher Education (Int J FYHE explores the transition experience of the first year student but this issue, Volume 6 Issue 1, has several unique characteristics. As a publication, it has a significant transition feature of its own: This issue is the last under this title and the current journal is to undergo a transformation, re-emerging with a new title and look in time for the inaugural STARS Conference in Melbourne, Australia in July 2015.   These are exciting times, not only for our editorial team, but also for prospective authors as the new journal will broaden the current First Year focus to that of enhancing students’ tertiary experiences across their entire learning journey in all its multiplicity and complexity.

  12. Target Assembly Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Target Assembly Facility integrates new armor concepts into actual armored vehicles. Featuring the capability ofmachining and cutting radioactive materials, it...

  13. Targeting the tumor microenvironment

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, P.A.; Lee, G.Y.; Bissell, M.J.

    2006-11-07

    Despite some notable successes cancer remains, for the most part, a seemingly intractable problem. There is, however, a growing appreciation that targeting the tumor epithelium in isolation is not sufficient as there is an intricate mutually sustaining synergy between the tumor epithelial cells and their surrounding stroma. As the details of this dialogue emerge, new therapeutic targets have been proposed. The FDA has already approved drugs targeting microenvironmental components such as VEGF and aromatase and many more agents are in the pipeline. In this article, we describe some of the 'druggable' targets and processes within the tumor microenvironment and review the approaches being taken to disrupt these interactions.

  14. Bayesian multiple target tracking

    CERN Document Server

    Streit, Roy L

    2013-01-01

    This second edition has undergone substantial revision from the 1999 first edition, recognizing that a lot has changed in the multiple target tracking field. One of the most dramatic changes is in the widespread use of particle filters to implement nonlinear, non-Gaussian Bayesian trackers. This book views multiple target tracking as a Bayesian inference problem. Within this framework it develops the theory of single target tracking, multiple target tracking, and likelihood ratio detection and tracking. In addition to providing a detailed description of a basic particle filter that implements

  15. The Target Visitation Problem

    OpenAIRE

    Hildenbrandt, Achim

    2015-01-01

    The thesis considers the target visitation problem, a combinatorial optimization problem, which merges the classical traveling salesman problem with the linear ordering problem. In more detail, we are looking for a tour which visits a set of targets and which is optimal with respect to two different aspects: On the one hand, we have given a travel cost from each target to every other. On the other hand, we have preference values which tell us how much we would like to visit one target before ...

  16. Raytracing and Direct-Drive Targets

    Science.gov (United States)

    Schmitt, Andrew J.; Bates, Jason; Fyfe, David; Eimerl, David

    2013-10-01

    Accurate simulation of the effects of laser imprinting and drive asymmetries in directly driven targets requires the ability to distinguish between raytrace noise and the intensity structure produced by the spatial and temporal incoherence of optical smoothing. We have developed and implemented a smoother raytrace algorithm for our mpi-parallel radiation hydrodynamics code, FAST3D. The underlying approach is to connect the rays into either sheets (in 2D) or volume-enclosing chunks (in 3D) so that the absorbed energy distribution continuously covers the propagation area illuminated by the laser. We will describe the status and show the different scalings encountered in 2D and 3D problems as the computational size, parallelization strategy, and number of rays is varied. Finally, we show results using the method in current NIKE experimental target simulations and in proposed symmetric and polar direct-drive target designs. Supported by US DoE/NNSA.

  17. Optimal target VOI size for accurate 4D coregistration of DCE-MRI

    Science.gov (United States)

    Park, Brian; Mikheev, Artem; Zaim Wadghiri, Youssef; Bertrand, Anne; Novikov, Dmitry; Chandarana, Hersh; Rusinek, Henry

    2016-03-01

    Dynamic contrast enhanced (DCE) MRI has emerged as a reliable and diagnostically useful functional imaging technique. DCE protocol typically lasts 3-15 minutes and results in a time series of N volumes. For automated analysis, it is important that volumes acquired at different times be spatially coregistered. We have recently introduced a novel 4D, or volume time series, coregistration tool based on a user-specified target volume of interest (VOI). However, the relationship between coregistration accuracy and target VOI size has not been investigated. In this study, coregistration accuracy was quantitatively measured using various sized target VOIs. Coregistration of 10 DCE-MRI mouse head image sets were performed with various sized VOIs targeting the mouse brain. Accuracy was quantified by measures based on the union and standard deviation of the coregistered volume time series. Coregistration accuracy was determined to improve rapidly as the size of the VOI increased and approached the approximate volume of the target (mouse brain). Further inflation of the VOI beyond the volume of the target (mouse brain) only marginally improved coregistration accuracy. The CPU time needed to accomplish coregistration is a linear function of N that varied gradually with VOI size. From the results of this study, we recommend the optimal size of the VOI to be slightly overinclusive, approximately by 5 voxels, of the target for computationally efficient and accurate coregistration.

  18. Phantom study of PET/CT guided delineation of radiation therapy volume

    International Nuclear Information System (INIS)

    Objective: To propose a model-based method for calculating the threshold in GTV determination by 18F-FDG PET in a phantom study. Methods: A phantom was constructed of a 9 L cylindrical tank.Glass spheres with volumes ranging from 0.5 to 16 ml (0.5, 1, 2, 4, 8 and 16 ml) were suspended within the tank. The six spheres were filled with an identical concentration of FDG (203.5 MBq/L) and suspended within 3 different background baths of FDG (6.179, 16.021, 0 MBq/L) solutions, creating 3 target-to-background ratios of 32.96 : 1, 12.69 : 1 and target to zero background. A linear regressive function was constructed which represented the relationship between the threshold and the average activity concentration of the target. A 40% of maximum intensity threshold and the linear regressive function method were applied to define the spheres filled with 18F-FDG. The volume differences between the two methods and the true volumes of the spheres were compared with t-test. Results: The linear regressive function model was derived as:threshold =(mean target concentration + 2.6227)/1.9752. The results indicated that a smaller deviation occurred when the function was utilized to estimate the volumes of the phantoms as compared to the 40% of maximum intensity threshold method, but there were no significant differences between them (t=0.306, P>0.05). The effect of the linear regressive function on volume was such that when the phantom sphere volumes were ≥ 1 ml, the average deviation between the defined volumes and the true volumes of phantoms was 1.01%; but when the phantom sphere volume was 0.5 ml, the average deviation was 9.53%. When the 40% of maximum intensity threshold method was applied to define the phantom spheres of volume ≥2 ml, the average deviation between the defined volumes and the true volumes of phantoms was -4.62%; but, the average deviation of that was 19.9% when the volumes of spheres were 0.5 and 1 ml. When the linear regressive function was applied to phantom

  19. Enhanced Volume Rendering Techniques for High-Resolution Color Cryo-Imaging Data

    OpenAIRE

    Gargesha, Madhusudhana; Qutaish, Mohammed; Roy, Debashish; Steyer, Grant; Bartsch, Hauke; Wilson, David L.

    2009-01-01

    We are developing enhanced volume rendering techniques for color image data. One target application is cryo-imaging, which provides whole-mouse, micron-scale, anatomical color, and molecular fluorescence image volumes by alternatively sectioning and imaging the frozen tissue block face. With the rich color images provided by cryo-imaging, we use true-color volume rendering and visually enhance anatomical regions by proper selection of voxel opacity. To compute opacity, we use color and/or gra...

  20. Proposed Site Treatment Plan (PSTP). Volumes 1 and 2 and Reference Document

    Energy Technology Data Exchange (ETDEWEB)

    Helmich, E.; Noller, D.K.; Wierzbicki, K.S.; Bailey, L.L.

    1994-12-22

    The Compliance Plan Volume provides overall schedules with target dates for achieving compliance with the land disposal restrictions (LDR) and contains procedures to establish milestones to be enforced under the Order. Information regarding the technical evaluation of treatment options for SRS mixed wastes is contained in the Background Volume and is provided for informational purposes only.

  1. Semipermanent Volumization by an Absorbable Filler: Onlay Injection Technique to the Bone

    Directory of Open Access Journals (Sweden)

    Takanobu Mashiko, MD

    2013-04-01

    Conclusions: Semipermanent volumizing effects can be achieved by HA injection if the target area has an underlying bony floor. Periosteal stem cells may be activated by HA injection and may contribute to persistent volumizing effects. This treatment may be a much less invasive alternative to fat or bone grafting.

  2. Limitations of the planning organ at risk volume (PRV) concept

    International Nuclear Information System (INIS)

    Purpose: Previously, we determined a planning target volume (PTV) margin recipe for geometrical errors in radiotherapy equal to MT = 2Σ + 0.7σ, with Σ and σ standard deviations describing systematic and random errors, respectively. In this paper, we investigated margins for organs at risk (OAR), yielding the so-called planning organ at risk volume (PRV). Methods and Materials: For critical organs with a maximum dose (Dmax) constraint, we calculated margins such that Dmax in the PRV is equal to the motion averaged Dmax in the (moving) clinical target volume (CTV). We studied margins for the spinal cord in 10 head-and-neck cases and 10 lung cases, each with two different clinical plans. For critical organs with a dose-volume constraint, we also investigated whether a margin recipe was feasible. Results: For the 20 spinal cords considered, the average margin recipe found was: MR = 1.6Σ + 0.2σ with variations for systematic and random errors of 1.2Σ to 1.8Σ and -0.2σ to 0.6σ, respectively. The variations were due to differences in shape and position of the dose distributions with respect to the cords. The recipe also depended significantly on the volume definition of Dmax. For critical organs with a dose-volume constraint, the PRV concept appears even less useful because a margin around, e.g., the rectum changes the volume in such a manner that dose-volume constraints stop making sense. Conclusion: The concept of PRV for planning of radiotherapy is of limited use. Therefore, alternative ways should be developed to include geometric uncertainties of OARs in radiotherapy planning

  3. SHADOW MAPPING OR SHADOW VOLUME?

    Directory of Open Access Journals (Sweden)

    Hoshang Kolivand

    2011-01-01

    Full Text Available In this paper two techniques of shadow generation are described. Volume shadow is geometric base but shadow mapping is image base. Silhouette detection is a most expensive step to create volume shadow. Two algorithms to recognize silhouette are introduced. Stencil buffer and Z- buffer are two other tools for creating shadow by volume shadow technique. Both algorithms are implemented in virtual environment with moveable light source. Triangular method and the Visible-non visible method are introduced. The recent traditional silhouette detection and implementation techniques used in volume shadow algorithm are improved. With introduce flowchart of both algorithms, the last volume shadow algorithm using stencil buffer is rewritten. A very simple algorithm to create volume shadow is proposed. The last shadow mapping algorithm is rewritten. These techniques are poised to bring realism into commercial games. It may be use in virtual reality applications.

  4. Nano-oncologicals new targeting and delivery approaches

    CERN Document Server

    Alonso, Maria Jose

    2014-01-01

    This authoritative volume focuses on emerging technologies in cancer nano medicine, characterized by their multi-functionality and potential to address simultaneously diverse issues of clinical relevance in the treatment of cancer. The book consists of sixteen chapters divided into six sections: 1) Biological Barriers in Cancer; 2) Tumor Targeting; 3) Targeting the Immune System; 4) Gene Therapy; 5) Nano theranostics and 6) Translational Aspects of Nano-Oncologicals. The volume starts with an introduction describing the biological barriers associated with cancer therapy and highlighting ways

  5. Strategic Targeted Advertising

    NARCIS (Netherlands)

    A. Galeotti; J.L. Moraga-Gonzalez (José Luis)

    2003-01-01

    textabstractWe present a strategic game of pricing and targeted-advertising. Firms can simultaneously target price advertisements to different groups of customers, or to the entire market. Pure strategy equilibria do not exist and thus market segmentation cannot occur surely. Equilibria exhibit rand

  6. Pure HD polarized targets

    International Nuclear Information System (INIS)

    The HD polarized target project is now ready to use a target in a physics experiment. This must be done in early 1998 at LEGS (BNL). The IPN cryogenic group takes its part in this venture by doing the transfer and in-beam cryostats. (authors)

  7. The CNGS target

    CERN Multimedia

    Patrice Loïez

    2005-01-01

    The CERN Neutrinos to Gran Sasso (CNGS) target ‘magazine’ of five target units. Each unit contains a series of 10-cm long graphite rods distributed over a length of 2 m. It is designed to maximize the number of secondary particles produced and hence the number of neutrinos. One unit is used at a time to prevent over heating.

  8. Probability distributions of landslide volumes

    OpenAIRE

    M. T. Brunetti; Guzzetti, F.; M. Rossi

    2009-01-01

    We examine 19 datasets with measurements of landslide volume, VL, for sub-aerial, submarine, and extraterrestrial mass movements. Individual datasets include from 17 to 1019 landslides of different types, including rock fall, rock slide, rock avalanche, soil slide, slide, and debris flow, with individual landslide volumes ranging over 10−4 m3≤VL≤1013 m3. We determine the probability density of landslide volumes, p(VL), using kernel density estimation. Each landslide...

  9. The physics of volume rendering

    OpenAIRE

    Peters, Thomas

    2014-01-01

    Radiation transfer is an important topic in several physical disciplines, probably most prominently in astrophysics. Computer scientists use radiation transfer, among other things, for the visualization of complex data sets with direct volume rendering. In this article, I point out the connection between physical radiation transfer and volume rendering, and I describe an implementation of direct volume rendering in the astrophysical radiation transfer code RADMC-3D. I show examples for the us...

  10. The physics of volume rendering

    Science.gov (United States)

    Peters, Thomas

    2014-11-01

    Radiation transfer is an important topic in several physical disciplines, probably most prominently in astrophysics. Computer scientists use radiation transfer, among other things, for the visualization of complex data sets with direct volume rendering. In this article, I point out the connection between physical radiation transfer and volume rendering, and I describe an implementation of direct volume rendering in the astrophysical radiation transfer code RADMC-3D. I show examples for the use of this module on analytical models and simulation data.

  11. The physics of volume rendering

    CERN Document Server

    Peters, Thomas

    2014-01-01

    Radiation transfer is an important topic in several physical disciplines, probably most prominently in astrophysics. Computer scientists use radiation transfer, among other things, for the visualisation of complex data sets with direct volume rendering. In this note, I point out the connection between physical radiation transfer and volume rendering, and I describe an implementation of direct volume rendering in the astrophysical radiation transfer code RADMC-3D. I show examples for the use of this module on analytical models and simulation data.

  12. Finding related functional neuroimaging volumes

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup; Hansen, Lars Kai

    2004-01-01

    We describe a content-based image retrieval technique for finding related functional neuroimaging experiments by voxelization of sets of stereotactic coordinates in Talairach space, comparing the volumes and reporting related volumes in a sorted list. Voxelization is accomplished by convolving each...... coordinate with a Gaussian kernel. The scheme allows us to compare experiments represented as either lists of coordinates or volumes, and we introduce alternative entrances to databases by image-based indices constructed via novelty measures and singular value decomposition....

  13. Heliophysics 3 Volume Set

    Science.gov (United States)

    Schrijver, Carolus J.; Siscoe, George L.

    2010-11-01

    Volume 1: Preface; 1. Prologue Carolus J. Schrijver and George L. Siscoe; 2. Introduction to heliophysics Thomas J. Bogdan; 3. Creation and destruction of magnetic field Matthias Rempel; 4. Magnetic field topology Dana W. Longcope; 5. Magnetic reconnection Terry G. Forbes; 6. Structures of the magnetic field Mark B. Moldwin, George L. Siscoe and Carolus J. Schrijver; 7. Turbulence in space plasmas Charles W. Smith; 8. The solar atmosphere Viggo H. Hansteen; 9. Stellar winds and magnetic fields Viggo H. Hansteen; 10. Fundamentals of planetary magnetospheres Vytenis M. Vasyliūnas; 11. Solar-wind magnetosphere coupling: an MHD perspective Frank R. Toffoletto and George L. Siscoe; 12. On the ionosphere and chromosphere Tim Fuller-Rowell and Carolus J. Schrijver; 13. Comparative planetary environments Frances Bagenal; Bibliography; Index. Volume 2: Preface; 1. Perspective on heliophysics George L. Siscoe and Carolus J. Schrijver; 2. Introduction to space storms and radiation Sten Odenwald; 3. In-situ detection of energetic particles George Gloeckler; 4. Radiative signatures of energetic particles Tim Bastian; 5. Observations of solar and stellar eruptions, flares, and jets Hugh Hudson; 6. Models of coronal mass ejections and flares Terry Forbes; 7. Shocks in heliophysics Merav Opher; 8. Particle acceleration in shocks Dietmar Krauss-Varban; 9. Energetic particle transport Joe Giacalone; 10. Energy conversion in planetary magnetospheres Vytenis Vasyliūnas; 11. Energization of trapped particles Janet Green; 12. Flares, CMEs, and atmospheric responses Tim Fuller-Rowell and Stanley C. Solomon; 13. Energetic particles and manned spaceflight 358 Stephen Guetersloh and Neal Zapp; 14. Energetic particles and technology Alan Tribble; Appendix I. Authors and editors; List of illustrations; List of tables; Bibliography; Index. Volume 3: Preface; 1. Interconnectedness in heliophysics Carolus J. Schrijver and George L. Siscoe; 2. Long-term evolution of magnetic activity of Sun

  14. Targeted therapy in lymphoma

    Directory of Open Access Journals (Sweden)

    Cavalli Franco

    2010-11-01

    Full Text Available Abstract Discovery of new treatments for lymphoma that prolong survival and are less toxic than currently available agents represents an urgent unmet need. We now have a better understanding of the molecular pathogenesis of lymphoma, such as aberrant signal transduction pathways, which have led to the discovery and development of targeted therapeutics. The ubiquitin-proteasome and the Akt/mammalian target of rapamycin (mTOR pathways are examples of pathological mechanisms that are being targeted in drug development efforts. Bortezomib (a small molecule protease inhibitor and the mTOR inhibitors temsirolimus, everolimus, and ridaforolimus are some of the targeted therapies currently being studied in the treatment of aggressive, relapsed/refractory lymphoma. This review will discuss the rationale for and summarize the reported findings of initial and ongoing investigations of mTOR inhibitors and other small molecule targeted therapies in the treatment of lymphoma.

  15. Evaluating the agreement between tumour volumetry and the estimated volumes of tumour lesions using an algorithm

    International Nuclear Information System (INIS)

    To evaluate the agreement between tumour volume derived from semiautomated volumetry (SaV) and tumor volume defined by spherical volume using longest lesion diameter (LD) according to Response Evaluation Criteria In Solid Tumors (RECIST) or ellipsoid volume using LD and longest orthogonal diameter (LOD) according to World Health Organization (WHO) criteria. Twenty patients with metastatic colorectal cancer from the CIOX trial were included. A total of 151 target lesions were defined by baseline computed tomography and followed until disease progression. All assessments were performed by a single reader. A variance component model was used to compare the three volume versions. There was a significant difference between the SaV and RECIST-based tumour volumes. The same model showed no significant difference between the SaV and WHO-based volumes. Scatter plots showed that the RECIST-based volumes overestimate lesion volume. The agreement between the SaV and WHO-based relative changes in tumour volume, evaluated by intraclass correlation, showed nearly perfect agreement. Estimating the volume of metastatic lesions using both the LD and LOD (WHO) is more accurate than those based on LD only (RECIST), which overestimates lesion volume. The good agreement between the SaV and WHO-based relative changes in tumour volume enables a reasonable approximation of three-dimensional tumour burden. (orig.)

  16. Evaluating the agreement between tumour volumetry and the estimated volumes of tumour lesions using an algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Laubender, Ruediger P. [German Cancer Consortium (DKTK), Heidelberg (Germany); University Hospital Munich - Campus Grosshadern, Institute of Medical Informatics, Biometry, and Epidemiology (IBE), Munich (Germany); German Cancer Research Center (DKFZ), Heidelberg (Germany); Lynghjem, Julia; D' Anastasi, Melvin; Graser, Anno [University Hospital Munich - Campus Grosshadern, Institute for Clinical Radiology, Munich (Germany); Heinemann, Volker; Modest, Dominik P. [University Hospital Munich - Campus Grosshadern, Department of Medical Oncology, Munich (Germany); Mansmann, Ulrich R. [University Hospital Munich - Campus Grosshadern, Institute of Medical Informatics, Biometry, and Epidemiology (IBE), Munich (Germany); Sartorius, Ute; Schlichting, Michael [Merck KGaA, Darmstadt (Germany)

    2014-07-15

    To evaluate the agreement between tumour volume derived from semiautomated volumetry (SaV) and tumor volume defined by spherical volume using longest lesion diameter (LD) according to Response Evaluation Criteria In Solid Tumors (RECIST) or ellipsoid volume using LD and longest orthogonal diameter (LOD) according to World Health Organization (WHO) criteria. Twenty patients with metastatic colorectal cancer from the CIOX trial were included. A total of 151 target lesions were defined by baseline computed tomography and followed until disease progression. All assessments were performed by a single reader. A variance component model was used to compare the three volume versions. There was a significant difference between the SaV and RECIST-based tumour volumes. The same model showed no significant difference between the SaV and WHO-based volumes. Scatter plots showed that the RECIST-based volumes overestimate lesion volume. The agreement between the SaV and WHO-based relative changes in tumour volume, evaluated by intraclass correlation, showed nearly perfect agreement. Estimating the volume of metastatic lesions using both the LD and LOD (WHO) is more accurate than those based on LD only (RECIST), which overestimates lesion volume. The good agreement between the SaV and WHO-based relative changes in tumour volume enables a reasonable approximation of three-dimensional tumour burden. (orig.)

  17. SU-E-J-79: Internal Tumor Volume Motion and Volume Size Assessment Using 4D CT Lung Data

    International Nuclear Information System (INIS)

    Purpose: To assess internal tumor volume change through breathing cycle and associated tumor motion using the 4DCT data. Methods: Respiration induced volume change through breathing cycle and associated motion was analyzed for nine patients that were scanned during the different respiratory phases. The examined datasets were the maximum and average intensity projections (MIP and AIP) and the 10 phases of the respiratory cycle. The internal target volume (ITV) was delineated on each of the phases and the planning target volume (PTV) was then created by adding setup margins to the ITV. Tumor motion through the phases was assessed using the acquired 4DCT dataset, which was then used to determine if the margins used for the ITV creation successfully encompassed the tumor in three dimensions. Results: Results showed that GTV motion along the superior inferior axes was the largest in all the cases independent of the tumor location and/or size or the use of abdomen compression. The extent of the tumor motion was found to be connected with the size of the GTV. The smallest GTVs exhibited largest motion vector independent of the tumor location. The motion vector size varied through the phases depending on the tumor size and location and it was smallest for phases 20 and 30. The smaller the volume of the delineated GTV, the greater its volume difference through the different respiratory phases was. The average GTV volume change was largest for the phases 60 and 70. Conclusion: Even if GTV is delineated using both AIP and MIP datasets, its motion extent will exceed the used margins especially for the very small GTV volumes. When the GTV size is less than 10 cc it is recommended to use fusion of the GTVs through all the phases to create the planning ITV

  18. Volume and Surface-Enhanced Volume Negative Ion Sources

    CERN Document Server

    Stockli, M P

    2013-01-01

    H- volume sources and, especially, caesiated H- volume sources are important ion sources for generating high-intensity proton beams, which then in turn generate large quantities of other particles. This chapter discusses the physics and technology of the volume production and the caesium-enhanced (surface) production of H- ions. Starting with Bacal's discovery of the H- volume production, the chapter briefly recounts the development of some H- sources, which capitalized on this process to significantly increase the production of H- beams. Another significant increase was achieved in the 1990s by adding caesiated surfaces to supplement the volume-produced ions with surface-produced ions, as illustrated with other H- sources. Finally, the focus turns to some of the experience gained when such a source was successfully ramped up in H- output and in duty factor to support the generation of 1 MW proton beams for the Spallation Neutron Source.

  19. LLE Review Quarterly Report (January-March 2000). Volume 82

    Energy Technology Data Exchange (ETDEWEB)

    Radha, P. B. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics

    2000-03-01

    This volume of the LLE Review, covering the period January-March 2000, includes a report on OMEGA cryogenic target designs for the soon-to-be-commissioned OMEGA Cryogenic Target Handling System. R. P. J. Town, J. A. Delettrez, R. Epstein, V. N. Goncharov, P. W. McKenty, P. B. Radha, and S. Skupsky use two-dimensional hydrodynamic simulations in conjunction with a stability analysis model to study the performance of OMEGA cryogenic capsules. They show that these targets are energy-scaled from the NIF ignition designs and have similar 1-D behavior and stability properties. This similarity will facilitate the extrapolation of cryogenic target studies on OMEGA to ignition targets on the NIF. Other articles in this volume are: Imprint Reduction using an Intensity Spike in Omega Cryogenic Targets; Measurement of Preheat Due to Fast Electrons in Laser Implosions; Holographic Transmission Gratings for Spectral Dispersion; Laser Beam Smoothing Caused by the Small-Spatial-Scale B-Integral; Three-Dimensional Modeling of Capsule Implosions in OMEGA Tetrahedral Hohlraums; and, Nanoindentation Hardness of Particles Used in Magnetoheological finishing (MRF).

  20. FT coverage and UK target price run-ups

    OpenAIRE

    Siganos, Antonios; Papa, Marco

    2015-01-01

    We focus on the market expectation hypothesis to explain the increase in share prices and trading volume of target firms before their merger announcements that have conventionally been attributed to either insider trading or market expectation. We use Financial Times (FT) coverage as a proxy of merger expectation and search for relevant articles for 783 UK target firms between 1998 and 2010. We identify a total of 1049 rumour articles and find that the FT market expectation proxy explains a s...

  1. Draft Site Treatment Plan (DSTP), Volumes I and II

    International Nuclear Information System (INIS)

    Site Treatment Plans (STP) are required for facilities at which the DOE generates or stores mixed waste. This Draft Site Treatment Plan (DSTP) the second step in a three-phase process, identifies the currently preferred options for treating mixed waste at the Savannah River Site (SRS) or for developing treatment technologies where technologies do not exist or need modification. The DSTP reflects site-specific preferred options, developed with the state's input and based on existing available information. To the extent possible, the DSTP identifies specific treatment facilities for treating the mixed waste and proposes schedules. Where the selection of specific treatment facilities is not possible, schedules for alternative activities such as waste characterization and technology assessment are provided. All schedule and cost information presented is preliminary and is subject to change. The DSTP is comprised of two volumes: this Compliance Plan Volume and the Background Volume. This Compliance Plan Volume proposes overall schedules with target dates for achieving compliance with the land disposal restrictions (LDR) of RCRA and procedures for converting the target dates into milestones to be enforced under the Order. The more detailed discussion of the options contained in the Background Volume is provided for informational purposes only

  2. Draft Site Treatment Plan (DSTP), Volumes I and II

    Energy Technology Data Exchange (ETDEWEB)

    D`Amelio, J.

    1994-08-30

    Site Treatment Plans (STP) are required for facilities at which the DOE generates or stores mixed waste. This Draft Site Treatment Plan (DSTP) the second step in a three-phase process, identifies the currently preferred options for treating mixed waste at the Savannah River Site (SRS) or for developing treatment technologies where technologies do not exist or need modification. The DSTP reflects site-specific preferred options, developed with the state`s input and based on existing available information. To the extent possible, the DSTP identifies specific treatment facilities for treating the mixed waste and proposes schedules. Where the selection of specific treatment facilities is not possible, schedules for alternative activities such as waste characterization and technology assessment are provided. All schedule and cost information presented is preliminary and is subject to change. The DSTP is comprised of two volumes: this Compliance Plan Volume and the Background Volume. This Compliance Plan Volume proposes overall schedules with target dates for achieving compliance with the land disposal restrictions (LDR) of RCRA and procedures for converting the target dates into milestones to be enforced under the Order. The more detailed discussion of the options contained in the Background Volume is provided for informational purposes only.

  3. AA antiproton production target

    CERN Multimedia

    1979-01-01

    The first version of the antiproton production target was a tungsten rod, 11 cm long and 3 mm in diameter. The rod was embedded in graphite, pressure-seated into an outer casing of stainless steel. At the entrance to the target assembly was a scintillator screen, imprinted with circles every 5 mm in radius, which allowed to precisely aim the 26 GeV high-intensity proton beam from the PS onto the centre of the target rod. The scintillator screen was a 1 mm thick plate of Cr-doped alumina. See also 7903034 and 7905091.

  4. Sparse PDF Volumes for Consistent Multi-Resolution Volume Rendering

    KAUST Repository

    Sicat, Ronell

    2014-12-31

    This paper presents a new multi-resolution volume representation called sparse pdf volumes, which enables consistent multi-resolution volume rendering based on probability density functions (pdfs) of voxel neighborhoods. These pdfs are defined in the 4D domain jointly comprising the 3D volume and its 1D intensity range. Crucially, the computation of sparse pdf volumes exploits data coherence in 4D, resulting in a sparse representation with surprisingly low storage requirements. At run time, we dynamically apply transfer functions to the pdfs using simple and fast convolutions. Whereas standard low-pass filtering and down-sampling incur visible differences between resolution levels, the use of pdfs facilitates consistent results independent of the resolution level used. We describe the efficient out-of-core computation of large-scale sparse pdf volumes, using a novel iterative simplification procedure of a mixture of 4D Gaussians. Finally, our data structure is optimized to facilitate interactive multi-resolution volume rendering on GPUs.

  5. Targeted therapies for cancer

    Science.gov (United States)

    ... to be untrue. Possible side effects from targeted therapies include: Diarrhea Liver problems Skin problems such as rash, dry skin, and nail changes Problems with blood clotting and wound healing High blood pressure As with any treatment, you ...

  6. SETI target selection.

    Science.gov (United States)

    Latham, D. W.; Soderblom, D. R.

    1995-06-01

    The NASA High Resolution Microwave Survey consists of two complementary elements: a Sky Survey of the entire sky to a moderate level of sensitivity; and a Targeted Search of nearby stars, one at a time, to a much deeper level of sensitivity. The authors propose strategies for target selection with two goals: to improve the chances of successful detection of signals from technical civilizations that inhabit planets around solar-type stars, and to minimize the chances of missing signals from unexpected sites.

  7. High pressure gas target

    Science.gov (United States)

    Gelbart, W.; Johnson, R. R.; Abeysekera, B.

    2012-12-01

    Compact, high pressure, high current gas target features all metal construction and semi-automatic window assembly change. The unique aspect of this target is the domed-shaped window. The Havar alloy window is electron beam welded to a metal ring, thus forming one, interchangeable assembly. The window assembly is sealed by knife-edges locked by a pneumatic toggle allowing a quick, in situ window change.

  8. Volumetric Spectroscopic Imaging of Glioblastoma Multiforme Radiation Treatment Volumes

    International Nuclear Information System (INIS)

    Purpose: Magnetic resonance (MR) imaging and computed tomography (CT) are used almost exclusively in radiation therapy planning of glioblastoma multiforme (GBM), despite their well-recognized limitations. MR spectroscopic imaging (MRSI) can identify biochemical patterns associated with normal brain and tumor, predominantly by observation of choline (Cho) and N-acetylaspartate (NAA) distributions. In this study, volumetric 3-dimensional MRSI was used to map these compounds over a wide region of the brain and to evaluate metabolite-defined treatment targets (metabolic tumor volumes [MTV]). Methods and Materials: Volumetric MRSI with effective voxel size of ∼1.0 mL and standard clinical MR images were obtained from 19 GBM patients. Gross tumor volumes and edema were manually outlined, and clinical target volumes (CTVs) receiving 46 and 60 Gy were defined (CTV46 and CTV60, respectively). MTVCho and MTVNAA were constructed based on volumes with high Cho and low NAA relative to values estimated from normal-appearing tissue. Results: The MRSI coverage of the brain was between 70% and 76%. The MTVNAA were almost entirely contained within the edema, and the correlation between the 2 volumes was significant (r=0.68, P=.001). In contrast, a considerable fraction of MTVCho was outside of the edema (median, 33%) and for some patients it was also outside of the CTV46 and CTV60. These untreated volumes were greater than 10% for 7 patients (37%) in the study, and on average more than one-third (34.3%) of the MTVCho for these patients were outside of CTV60. Conclusions: This study demonstrates the potential usefulness of whole-brain MRSI for radiation therapy planning of GBM and revealed that areas of metabolically active tumor are not covered by standard RT volumes. The described integration of MTV into the RT system will pave the way to future clinical trials investigating outcomes in patients treated based on metabolic information

  9. An ISOLDE target unit

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    A good dozen different targets are available for ISOLDE, made of different materials and equipped with different kinds of ion-sources, according to the needs of the experiments. Each separator (GPS: general purpose; HRS: high resolution) has its own target. Because of the high radiation levels, robots effect the target changes, about 80 times per year. In the standard unit shown in picture _01, the target is the cylindrical object in the front. It contains uranium-carbide kept at a temperature of 2200 deg C, necessary for the isotopes to be able to escape. At either end, one sees the heater current leads, carrying 700 A. The Booster beam, some 3E13 protons per pulse, enters the target from left. The evaporated isotope atoms enter a hot-plasma ion source (the black object behind the target). The whole unit sits at 60 kV potential (pulsed in synchronism with the arrival of the Booster beam) which accelerates the ions (away from the viewer) towards one of the 2 separators.

  10. Radar target detection simulation

    Directory of Open Access Journals (Sweden)

    Tarig Ibrahim Osman

    2014-12-01

    Full Text Available Standard radar detection process requires that the sensor output is compared to a predetermined threshold. The threshold is selected based on a-priori knowledge available and/or certain assumptions. However, any knowledge and/or assumptions become in adequate due to the presence of multiple targets with varying signal return and usually non stationary background. Thus, any predetermined threshold may result in either increased false alarm rate or increased track loss. Even approaches where the threshold is adaptively varied will not perform well in situations when the signal return from the target of interest is too low compared to the average level of the background .Track-before-detect techniques eliminate the need for a detection threshold and provide detecting and tracking targets with lower signal-to-noise ratios than standard methods. However, although trackbefore-detect techniques eliminate the need for detection threshold at sensor's signal processing stage, they often use tuning thresholds at the output of the filtering stage .This paper presents a computerized simulation model for target detection process. Moreover, the proposed model method is based on the target motion models, the output of the detection process can easily be employed for maneuvering target tracking.

  11. Volume Ignition via Time-like Detonation in Pellet Fusion

    CERN Document Server

    Csernai, L P

    2015-01-01

    Relativistic fluid dynamics and the theory of relativistic detonation fronts are used to estimate the space-time dynamics of the burning of the D-T fuel in Laser driven pellet fusion experiments. The initial "High foot" heating of the fuel makes the compressed target transparent to radiation, and then a rapid ignition pulse can penetrate and heat up the whole target to supercritical temperatures in a short time, so that most of the interior of the target ignites almost simultaneously and instabilities will have no time to develop. In these relativistic, radiation dominated processes both the interior, time-like burning front and the surrounding space-like part of the front will be stable against Rayleigh-Taylor instabilities. To achieve this rapid, volume ignition the pulse heating up the target to supercritical temperature should provide the required energy in less than ~ 10 ps.

  12. Minivoids in the Local Volume

    CERN Document Server

    Tikhonov, A V

    2006-01-01

    We consider a sphere of 7.5 Mpc radius, which contains 355 galaxies with accurately measured distances, to detect the nearest empty volumes. Using a simple void detection algorithm, we found six large (mini)voids in Aquila, Eridanus, Leo, Vela, Cepheus and Octans, each of more than 30 Mpc^3. Besides them, 24 middle-size "bubbles" of more than 5 Mpc^3 volume are detected, as well as 52 small "pores". The six largest minivoids occupy 58% of the considered volume. Addition of the bubbles and pores to them increases the total empty volume up to 75% and 81%, respectively. The detected local voids look like oblong potatoes with typical axial ratios b/a = 0.75 and c/a = 0.62 (in the triaxial ellipsoide approximation). Being arranged by the size of their volume, local voids follow power law of volumes-rankes dependence. A correlation Gamma-function of the Local Volume galaxies follows a power low with a formally calculated fractal dimension D = 1.5. We found that galaxies surrounding the local minivoids do not differ...

  13. Sonographic measurement of gallbladder volume.

    Science.gov (United States)

    Dodds, W J; Groh, W J; Darweesh, R M; Lawson, T L; Kishk, S M; Kern, M K

    1985-11-01

    Sonographic images of the gallbladder enable satisfactory approximation of gallbladder volume using the sum-of-cylinders method. The sum-of-cylinder measurements, however, are moderately cumbersome and time consuming to perform. In this investigation, in vitro and in vivo testing was done to determine that a simple ellipsoid method applied to sonographic gallbladder images yields reasonable volume approximations that are comparable to the volumes calculated by the sum-of-cylinders method. Findings from a water-bath experiment showed that measurement of gallbladder volume by the ellipsoid method closely approximated the true volume with a mean difference of about 1.0 ml. The results of in vivo studies in five volunteers demonstrated that the gallbladder contracted substantially after a fatty meal and that volumes calculated by the ellipsoid and sum-of-cylinders methods were nearly identical. Thus, a simple ellipsoid method, requiring negligible time, may be used to approximate satisfactory gallbladder volume for clinical or investigative studies. PMID:3901703

  14. Maximum static inspiratory and expiratory pressures with different lung volumes

    Directory of Open Access Journals (Sweden)

    Johnson Monique M

    2006-05-01

    Full Text Available Abstract Background Maximum pressures developed by the respiratory muscles can indicate the health of the respiratory system, help to determine maximum respiratory flow rates, and contribute to respiratory power development. Past measurements of maximum pressures have been found to be inadequate for inclusion in some exercise models involving respiration. Methods Maximum inspiratory and expiratory airway pressures were measured over a range of lung volumes in 29 female and 19 male adults. A commercial bell spirometry system was programmed to occlude airflow at nine target lung volumes ranging from 10% to 90% of vital capacity. Results In women, maximum expiratory pressure increased with volume from 39 to 61 cmH2O and maximum inspiratory pressure decreased with volume from 66 to 28 cmH2O. In men, maximum expiratory pressure increased with volume from 63 to 97 cmH2O and maximum inspiratory pressure decreased with volume from 97 to 39 cmH2O. Equations describing pressures for both sexes are: Pe/Pmax = 0.1426 Ln( %VC + 0.3402 R2 = 0.95 Pi/Pmax = 0.234 Ln(100 - %VC - 0.0828 R2 = 0.96 Conclusion These results were found to be consistent with values and trends obtained by other authors. Regression equations may be suitable for respiratory mechanics models.

  15. FY 1996 solid waste integrated life-cycle forecast volume summary - Volume 1 and Volume 2

    International Nuclear Information System (INIS)

    Solid waste forecast volumes to be generated or received;at Westinghouse Hanford Company's Solid Waste program over the life cycle of the site are described in this report. Previous forecast summary reports have covered only a 30-year period; however, the life-cycle approach was adopted for this FY 1996 report to ensure consistency with waste volumes reported in the 1996 Multi-Year Program Plans (MYPP). The volume data were collected on a life-cycle basis from onsite and offsite waste generators who currently ship or plan to ship solid waste to the Solid Waste program. The volumes described in detail are low-level mixed waste (LLMW) and transuranic/transuranic-mixed (TRU(M)) waste. The volumes reported in this document represent the external volume of the containers selected to ship the waste. Summary level information pertaining to low-level waste (LLW) is described in Appendix B. Hazardous waste volumes are also provided in Appendices E and F but are not described in detail since they will be managed by a commercial facility. Emphasis is placed on LLMW and TRU(M) waste because it will require processing and storage at Hanford Solid Waste's Central Waste Complex (CORK) prior to final disposal. The LLW will generally be sent directly to disposal. The total baselines volume of LLMW and TRU(M) waste forecast to be received by the Solid Waste program (until 2070) is approximately 100,900 cubic meters. This total waste volume is composed of the following waste categories: 077,080 cubic meters of LLMW; 23,180 cubic meters of TRU(M); 640 cubic meters of greater-than-class III LLMW. This total is about 40% of the total volume reported last year (FY 1995)

  16. Maximising Target Language Use in the Immersion Classroom

    Science.gov (United States)

    Veque, Catherine

    2006-01-01

    This article is the second part of a report on research that examined immersion language teachers' strategies to modify their speech in order to maintain use of the target language. As described in the first part in "Babel," Volume 40, Number 2 (Veque, 2005), this classroom-based research, undertaken at Methodist Ladies College (MLC) in Melbourne,…

  17. Plasma volume changes during hypoglycaemia

    DEFF Research Database (Denmark)

    Hilsted, J; Bendtsen, F; Christensen, N J;

    1990-01-01

    To investigate whether previously reported changes in venous blood volume and composition induced by acute hypoglycaemia in humans are representative for the entire body we measured erythrocyte 51Cr content, haematocrit, plasma volume, intravascular albumin content and transcapillary escape rate of...... albumin in arterial and venous blood in seven healthy subjects before and during insulin-induced hypoglycaemia. In both vascular sites blood 51Cr content and the haematocrit increased, plasma volume and intravascular albumin content decreased and the transcapillary escape rate of albumin increased during...

  18. Plasma volume changes during hypoglycaemia

    DEFF Research Database (Denmark)

    Hilsted, J; Frandsen, Henrik Lund; Christensen, N J;

    1991-01-01

    -induced hypoglycaemia with total autonomic blockade (alpha-adrenoceptor blockade combined with beta-adrenoceptor blockade and atropine); and insulin-induced hypoglycaemia without any autonomic blockade. In the experiments without autonomic blockade the peripheral venous hematocrit increased, plasma volume decreased......, intravascular albumin content decreased and the transcapillary escape rate of albumin increased. In both experiments with autonomic blockade the increase in venous haematocrit was abolished, yet plasma volume decreased, intravascular albumin content decreased and the transcapillary escape rate of albumin...... increased in these experiments. Thus, the changes in plasma volume and composition in response to hypoglycaemia are due to the combined actions of adrenaline and of insulin....

  19. Dictionary Based Segmentation in Volumes

    DEFF Research Database (Denmark)

    Emerson, Monica Jane; Jespersen, Kristine Munk; Jørgensen, Peter Stanley;

    2015-01-01

    We present a method for supervised volumetric segmentation based on a dictionary of small cubes composed of pairs of intensity and label cubes. Intensity cubes are small image volumes where each voxel contains an image intensity. Label cubes are volumes with voxelwise probabilities for a given...... label. The segmentation process is done by matching a cube from the volume, of the same size as the dictionary intensity cubes, to the most similar intensity dictionary cube, and from the associated label cube we get voxel-wise label probabilities. Probabilities from overlapping cubes are averaged and...

  20. Cell swelling and volume regulation

    DEFF Research Database (Denmark)

    Hoffmann, Else Kay

    1992-01-01

    The extracellular space in the brain is typically 20% of the tissue volume and is reduced to at least half its size under conditions of neural insult. Whether there is a minimum size to the extracellular space was discussed. A general model for cell volume regulation was presented, followed by a...... discussion on how many of the generally involved mechanisms are identified in neural cells and (or) in astrocytes. There seems to be clear evidence suggesting that parallel K+ and Cl- channels mediate regulatory volume decrease in primary cultures of astrocytes, and a stretch-activated cation channel has...

  1. Particles in small volume injections.

    Science.gov (United States)

    Taylor, S A; Spence, J

    1983-12-01

    The level of particulate contamination in small volume injections has been examined using the light blockage (HIAC) and electrical sensing zone (Coulter counter) techniques, the HIAC system being found to be the more suitable. Particle counts on the same batch of injection showed a large and variable difference between the HIAC and the Coulter counter results, especially below 5 micron. None of the injections examined complied with the British Pharmacopoeia limits for particulates in large volume parenterals, suggesting the unsuitability of the limits for small volume parenterals. PMID:6141237

  2. Preliminary study of the internal margin of the gross tumor volume in thoracic esophageal cancer

    International Nuclear Information System (INIS)

    Purpose. - To measure the displacement of the tumor of the gross tumor volume (GTV) of thoracic esophageal cancer in the calm states of end-inspiration and end-expiration for determining the internal margin of the GTV (IGTV). Methods. - Twenty-two patients with thoracic esophageal cancer who were unable to undergo surgery were identified in our hospital. The patients received radiotherapy. By using 16-slice spiral computed tomography (CT), we acquired the calm states of end-inspiration and end-expiration. The displacement and volume changes in tumor target volume were measured, and the changes were analyzed to determine if these were associated with the tidal volume and the location and length of the target volume V. In the end, we analyzed the displacement of tumor target volume and calculated the internal margin of the GTV by empirical formula. Results. - The average tidal volume was 463.6 ml. The average GTV at end-inspiration was 33.3 ml and at end-expiration was 33.35 ml. Three was not any significant between two groups (T -0.034, P > 0.05). The IGTV (X-axis direction) was 3.09 mm for the right sector and 4.08 mm for the left border; the IGTV (Z-axis direction) was 3.96 mm for the anterior border and 2.83 mm for the posterior border; and the IGTV (Y-axis direction) was 7.31 mm for the upper boundary (head direction) and 10.16 mm for the lower boundary (feet direction). The motion of the GTV showed no significant correlation with the tidal volume of patients and the length of the tumor, but in relation to the tumor location, the displacement of the lower thoracic and the middle thoracic target volumes occurred in the direction of the anterior and right, which were not significantly different (T = 0.859, 0.229, P > 0.05) The significant differences were observed for the other directions (P < 0.05). Conclusions. - Because of respiratory and organ movements, the displacement of the tumor target volume was different in all directions. Therefore, we recommend that

  3. LLE Review Quarterly Report (October - December 2007). Volume 113

    Energy Technology Data Exchange (ETDEWEB)

    Zuegel, Jonathan D. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics

    2007-12-01

    This volume of the LLE Review, covering October–December 2007, features “High-Intensity Laser–Plasma Interactions in the Refluxing Limit,” by P. M. Nilson, W. Theobald, J. Myatt, C. Stoeckl, M. Storm, O. V. Gotchev, J. D. Zuegel, R. Betti, D. D. Meyerhofer, and T. C. Sangster. In this article (p. 1), the authors report on target experiments using the Multi-Terawatt (MTW) Laser Facility to study isochoric heating of solid-density targets by fast electrons produced from intense, short-pulse laser irradiation. Electron refluxing occurs due to target-sheath field effects and contains most of the fast electrons within the target volume. This efficiently heats the solid-density plasma through collisions. X-ray spectroscopic measurements of absolute Kα (x-radiation) photon yields and variations of the Kβ/Kα b emission ratio both indicate that laser energy couples to fast electrons with a conversion efficiency of approximately 20%. Bulk electron temperatures of at least 200 eV are inferred for the smallest mass targets.

  4. Intensity modulated radiation therapy (IMRT) for better dose targeting

    International Nuclear Information System (INIS)

    Full text: Intensity modulated radiation therapy generally implies the use of inverse planning using preselected organ dose constraints and dose volume histogram analysis. Then modulated beams are created by multi leaf collimator (MLC) sequences. This new method of modulating each beam produces fine resolution dose maps around the target volume. New and exciting tumour visualisation techniques using PET and MRS imaging may ensure that the new technology in dose delivery is matched by improved biological aided targeting images which better specifying the tumour volume. Implementing IMRT into the clinic is a complex and time consuming task however some examples of clinical sites which lend themselves to IMRT over conventional radiotherapy will be shown. One vendors approach (the pinnacle radiotherapy planning computer) is described. It maintains forward computation of the final dose map to ensure integrity of the inverse planning process. Planning dose tool calculations are compared with film dosimetry results. These comparisons ensure accurate doses are delivered to the patient

  5. The Sinuous Target

    Energy Technology Data Exchange (ETDEWEB)

    Zwaska, R. [Fermilab

    2015-06-01

    We report on the concept for a target material comprised of a multitude of interlaced wires of small dimension. This target material concept is primarily directed at high-power neutrino targets where the thermal shock is large due to small beam sizes and short durations; it also has applications to other high-power targets, particularly where the energy deposition is great or a high surface area is preferred. This approach ameliorates the problem of thermal shock by engineering a material with high strength on the micro-scale, but a very low modulus of elasticity on the meso-scale. The low modulus of elasticity is achieved by constructing the material of spring-like wire segments much smaller than the beam dimension. The intrinsic bends of the wires will allow them to absorb the strain of thermal shock with minimal stress. Furthermore, the interlaced nature of the wires provides containment of any segment that might become loose. We will discuss the progress on studies of analogue materials and fabrication techniques for sinuous target materials.

  6. Targeted assets risk analysis.

    Science.gov (United States)

    Bouwsema, Barry

    2013-01-01

    Risk assessments utilising the consolidated risk assessment process as described by Public Safety Canada and the Centre for Security Science utilise the five threat categories of natural, human accidental, technological, human intentional and chemical, biological, radiological, nuclear or explosive (CBRNE). The categories of human intentional and CBRNE indicate intended actions against specific targets. It is therefore necessary to be able to identify which pieces of critical infrastructure represent the likely targets of individuals with malicious intent. Using the consolidated risk assessment process and the target capabilities list, coupled with the CARVER methodology and a security vulnerability analysis, it is possible to identify these targeted assets and their weaknesses. This process can help emergency managers to identify where resources should be allocated and funding spent. Targeted Assets Risk Analysis (TARA) presents a new opportunity to improve how risk is measured, monitored, managed and minimised through the four phases of emergency management, namely, prevention, preparation, response and recovery. To reduce risk throughout Canada, Defence Research and Development Canada is interested in researching the potential benefits of a comprehensive approach to risk assessment and management. The TARA provides a framework against which potential human intentional threats can be measured and quantified, thereby improving safety for all Canadians. PMID:23615063

  7. Production Target Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Woloshun, Keith Albert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Olivas, Eric Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-28

    The Northstar 99Mo production target, a cylindrical length of 100Mo rod, has evolved considerably since its first conception.  The cylinder was very early sliced into disks to increase the heat transfer area, first to 1 mm thick disks then to the current 0.5 mm thick.  The coolant was changed early in the target development from water to helium to eliminate corrosion and dissolution.  The diameter has increased from initially 6 mm to 12 mm, the current diameter of the test target now at ANL, to nominally 28 mm (26-30.6 mm, depending upon optimal beam spot size and shape).  The length has also changed to improve the production to cost ratio, so now the target is nominally 41 mm long (excluding coolant gaps between disks), and irradiated on both ends.  This report summarizes the current status of the plant target design.

  8. Inflation Forecast Targeting: Implementing and Monitoring Inflation Targets

    OpenAIRE

    Lars E.O. Svensson

    1996-01-01

    Inflation targeting is shown to imply inflation forecast targeting: the central bank's inflation forecast becomes an intermediate target. Inflation forecast targeting simplifies both implementing and monitoring of monetary policy. The inflation forecast is actually an ideal intermediate target: it is most correlated with the goal, easier to control than the goal, more observable than the goal, and very transparent. Money growth targeting generally leads to higher inflation variability than in...

  9. LLE Review Quarterly Report (October-December 1990). Volume 45

    Energy Technology Data Exchange (ETDEWEB)

    Epperlein, E. M. [Univ. of Rochester, NY (United States)

    1990-12-01

    This volume of the LLE Review, covering the period October-December 1990, contains descriptions of a new phase-conversion technique designed to improve irradiation uniformity, a report on the interpretation of highdensity implosion experiments of argon-filled targets, and an article on the use of absorption spectroscopy to diagnose compressed target layers. The section on advanced technology has a report on the application of KTP crystals as electro-optic amplitude modulators, and describes the use of chirped-pulse technology to measure X(3) by nearly degenerate four-wave mixing. Finally, the activities of the National Laser Users Facility and the GDL and OMEGA laser facilities are summarized.

  10. LLE Review quarterly report, April--June 1993. Volume 55

    Energy Technology Data Exchange (ETDEWEB)

    Hutchison, R.J. [ed.

    1993-10-01

    This volume of the LLE Review, covering the period April--June 1993, contains articles on spectral features from argon-filled target implosions on OMEGA, and on the theory of an implicit difference scheme for the Fokker-Planck equation. The advanced technology section includes reports on a novel polymer liquid-crystal wave plate and a new scheme for phase conversion of the OMEGA Upgrade beams that results in greater, smoother energy deposition on fusion targets. Finally, reports on the as-designed configuration of the OMEGA newly configured glass development laser system are summarized.

  11. LLE Review Quarterly Report (April-June 1994). Volume 59

    Energy Technology Data Exchange (ETDEWEB)

    Knauer, James P. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics

    1994-06-01

    This volume of the LLE Review, covering the period of April-June 1994, contains articles on surface characterization by atomic force microscopy; electron acceleration with intense laser field; spatial intensity variations induced by nonlinear beam propagation; backlighting of implosion targets exhibiting mix; and the use of cosmic rays to monitor large, multielement detectors. Four of these articles - surface characterization; nonlinear beam propagation; backlighting of mixed targets; and monitoring of the MEDUSA detector array - are related to the OMEGA Upgrade, which is currently under construction.

  12. 10 CFR 63.332 - Representative volume.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Representative volume. 63.332 Section 63.332 Energy... Protection Standards § 63.332 Representative volume. (a) The representative volume is the volume of ground... radionuclides released from the Yucca Mountain disposal system that will be in the representative volume....

  13. Carbohydrate plasma expanders for passive tumor targeting

    DEFF Research Database (Denmark)

    Hoffmann, Stefan; Caysa, Henrike; Kuntsche, Judith;

    2013-01-01

    The objective of this study was to investigate the suitability of carbohydrate plasma volume expanders as a novel polymer platform for tumor targeting. Many synthetic polymers have already been synthesized for targeted tumor therapy, but potential advantages of these carbohydrates include...... inexpensive synthesis, constant availability, a good safety profile, biodegradability and the long clinical use as plasma expanders. Three polymers have been tested for cytotoxicity and cytokine activation in cell cultures and conjugated with a near-infrared fluorescent dye: hydroxyethyl starches (HES 200 k......Da and HES 450 kDa) and dextran (DEX 500 kDa). Particle size and molecular weight distribution were determined by asymmetric flow field-flow fractionation (AF4). The biodistribution was investigated non-invasively in nude mice using multispectral optical imaging. The most promising polymer conjugate was...

  14. LLE review: Quarterly report, July--September 1995. Volume 64

    Energy Technology Data Exchange (ETDEWEB)

    Craxton, R.S. [ed.

    1995-09-01

    This volume of the LLE Review, covering the period July--September 1995, includes a description of the first target experiments performed on the upgraded OMEGA laser system. These experiments, carried out to active and test several diagnostics systems, have demonstrated successful functioning of the overall experimental system and have produced high neutron yields and high core temperatures. Other articles in this volume describe the diagnosis of core conditions using krypton line spectroscopy, a mix model for LILAC that can be applied to study the deceleration instability at the pusher-core interface, a simulated-annealing algorithm for improved phase-plate design, a simple method for characterizing the thickness and uniformity of transparent laser-fusion targets, and femtosecond pump-probe experiments on semiconducting YBCO.

  15. Setting reference targets

    International Nuclear Information System (INIS)

    Reference Targets are used to represent virtual quantities like the magnetic axis of a magnet or the definition of a coordinate system. To explain the function of reference targets in the sequence of the alignment process, this paper will first briefly discuss the geometry of the trajectory design space and of the surveying space, then continue with an overview of a typical alignment process. This is followed by a discussion on magnet fiducialization. While the magnetic measurement methods to determine the magnetic centerline are only listed (they will be discussed in detail in a subsequent talk), emphasis is given to the optical/mechanical methods and to the task of transferring the centerline position to reference targets

  16. Modelling Recycling Targets

    DEFF Research Database (Denmark)

    Hill, Amanda Louise; Leinikka Dall, Ole; Andersen, Frits M.

    2014-01-01

    Within the European Union (EU) a paradigm shift is currently occurring in the waste sector, where EU waste directives and national waste strategies are placing emphasis on resource efficiency and recycling targets. The most recent Danish resource strategy calculates a national recycling rate of 22......% for household waste, and sets an ambitious goal of a 50% recycling rate by 2020. This study integrates the recycling target into the FRIDA model to project how much waste and from which streams should be diverted from incineration to recycling in order to achieve the target. Furthermore, it discusses...... how the existing technological, organizational and legislative frameworks may affect recycling activities. The results of the analysis show that with current best practice recycling rates, the 50% recycling rate cannot be reached without recycling of household biowaste. It also shows that all Danish...

  17. Targeted Phototherapy (newer phototherapy

    Directory of Open Access Journals (Sweden)

    Zonunsanga

    2015-04-01

    Full Text Available Conventional phototherapy uses a whole body cabinet or body part machine such as hand, foot or scalp machines. They have many disadvantages due to which new phototherapy technique was then developed to overcome this situation. This new technique is called targeted phototherapy which includes excimer laser, intense pulse light system (IPL, photodynamic therapy and ultraviolet (UV light source with a sophisticated delivery system which is easy to be operated by hands. The mechanisms of action of targeted phototherapy systems are similar to those in conventional UVB/UVA therapy. They have many advantages like less chances of side effects, avoidance of exposure of unnecessary sites, faster response, shortening of the duration of treatments. But they have disadvantages like high costs and inability to use for extensive areas. This review article discusses targeted phototherapy in considerable to the mechanism of actions and advantages and disadvantages in comparison to the conventional phototherapy.

  18. Phoenix Color Targets

    Science.gov (United States)

    2008-01-01

    These images of three Phoenix color targets were taken on sols 1 and 2 by the Surface Stereo Imager (SSI) on board the Phoenix lander. The bottom target was imaged in approximate color (SSI's red, green, and blue filters: 600, 530, and 480 nanometers), while the others were imaged with an infrared filter (750 nanometers). All of them will be imaged many times over the mission to monitor the color calibration of the camera. The two at the top show grains 2 to 3 millimeters in size that were likely lifted to the Phoenix deck during landing. Each of the large color chips on each target contains a strong magnet to protect the interior material from Mars' magnetic dust. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  19. Anadromous fish inventory: Summary volume

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Summary volume, with discussion, on anadromous fish inventories, species lists, histories of fisheries, habitat, key spawning and rearing areas, runsescapements,...

  20. Organ volume estimation using SPECT

    CERN Document Server

    Zaidi, H

    1996-01-01

    Knowledge of in vivo thyroid volume has both diagnostic and therapeutic importance and could lead to a more precise quantification of absolute activity contained in the thyroid gland. In order to improve single-photon emission computed tomography (SPECT) quantitation, attenuation correction was performed according to Chang's algorithm. The dual-window method was used for scatter subtraction. We used a Monte Carlo simulation of the SPECT system to accurately determine the scatter multiplier factor k. Volume estimation using SPECT was performed by summing up the volume elements (voxels) lying within the contour of the object, determined by a fixed threshold and the gray level histogram (GLH) method. Thyroid phantom and patient studies were performed and the influence of 1) fixed thresholding, 2) automatic thresholding, 3) attenuation, 4) scatter, and 5) reconstruction filter were investigated. This study shows that accurate volume estimation of the thyroid gland is feasible when accurate corrections are perform...

  1. On algebraic volume density property

    OpenAIRE

    Kaliman, Shulim; Kutzschebauch, Frank

    2012-01-01

    A smooth affine algebraic variety $X$ equipped with an algebraic volume form $\\omega$ has the algebraic volume density property (AVDP) if the Lie algebra generated by completely integrable algebraic vector fields of $\\omega$-divergence zero coincides with the space of all algebraic vector fields of $\\omega$-divergence zero. We develop an effective criterion of verifying whether a given $X$ has AVDP. As an application of this method we establish AVDP for any homogeneous space $X=G/R$ that admi...

  2. Probability distributions of landslide volumes

    OpenAIRE

    M. T. Brunetti; Guzzetti, F.; M. Rossi

    2009-01-01

    We examine 19 datasets with measurements of landslide volume, VL, for sub-aerial, submarine, and extraterrestrial mass movements. Individual datasets include from 17 to 1019 landslides of different types, including rock fall, rock slide, rock avalanche, soil slide, slide, and debris flow, with individual landslide volumes ranging over 10−4 m3VL&am...

  3. Topology-controlled volume rendering

    OpenAIRE

    Weber, Gunther H.; Dillard, Scott E.; Carr, Hamish; Pascucci, Valerio; Hamann, Bernd

    2007-01-01

    Topology provides a foundation for the development of mathematically sound tools for processing and exploration of scalar fields. Existing topology-based methods can be used to identify interesting features in volumetric data sets, to find seed sets for accelerated isosurface extraction, or to treat individual connected components as distinct entities for isosurfacing or interval volume rendering. We describe a framework for direct volume rendering based on segmenting ...

  4. Interactive High P