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Target volume delineation

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https://www.readbyqxmd.com/read/29045239/contour-propagation-for-lung-tumor-delineation-in-4d-ct-using-tensor-product-surface-of-uniform-and-non-uniform-closed-cubic-b-splines
#1
Renchao Jin, Yongchuan Liu, Mi Chen, Sheng Zhang, Enmin Song
A robust contour propagation method is proposed to help physicians delineate lung tumors on all phase images of four-dimensional computer tomography (4D-CT) by only manually delineating the contours on a reference phase. The proposed method models the trajectory surface swept by a contour in a respiratory cycle as a tensor-product surface of two closed cubic B-spline curves: a non-uniform B-spline curve which models the contour and a uniform B-spline curve which models the trajectory of a point on the contour...
October 18, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29039108/preliminary-results-of-a-new-workflow-for-mri-ct-based-image-guided-brachytherapy-in-cervical-carcinoma
#2
Miho Watanabe Nemoto, Yuma Iwai, Gentaro Togasaki, Marie Kurokawa, Rintarou Harada, Hiroki Kobayashi, Takashi Uno
PURPOSE: We propose a method of image-guided brachytherapy (IGBT) that combines MRI-based target volume delineation for the first fraction with CT datasets of subsequent fractions, using an automatic, applicator-based co-registration, and report our preliminary experience. MATERIALS AND METHODS: The MRI of the first fraction was used for the first brachytherapy planning. For each subsequent brachytherapy fraction, after the same applicator insertion, a new CT scan with the applicator in place was obtained...
October 16, 2017: Japanese Journal of Radiology
https://www.readbyqxmd.com/read/29023527/dose-escalated-radiotherapy-for-unresectable-or-locally-recurrent-pancreatic-cancer-dose-volume-analysis-toxicity-and-outcome-of-28-consecutive-patients
#3
Sebastian Zschaeck, Bibiana Blümke, Peter Wust, David Kaul, Marcus Bahra, Hanno Riess, Fritz Klein, Marianne Sinn, Uwe Pelzer, Volker Budach, Pirus Ghadjar
PURPOSE: The role of radiotherapy for unresectable pancreatic cancer is controversial. A benefit of additional radiotherapy is supported by some observations. A dose-effect relationship was recently found by dose escalation employing image guided and intensity modulated radiotherapy. METHODS: We retrospectively evaluated 28 consecutive patients, all with history of extensive prior therapies for unresectable locally advanced/ recurrent pancreatic cancer (LAPC/LRPC)...
2017: PloS One
https://www.readbyqxmd.com/read/29022748/dependence-of-volume-calculation-and-margin-growth-accuracy-on-treatment-planning-systems-for-stereotactic-radiosurgery
#4
David J Eaton, Kevin Alty
OBJECTIVE: Uncertainties in radiotherapy target structures are partly dependent on differences between volume calculation and margin growing methods in treatment planning systems (TPS). These uncertainties are exacerbated with very small structures such as those common in stereotactic radiosurgery (SRS). METHODS: Data from a national commissioning programme for SRS was used to assess variation in reported volumes for 6 benchmark cases, including malignant and benign indications...
October 12, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28994459/neural-network-dose-models-for-knowledge-based-planning-in-pancreatic-sbrt
#5
Warren G Campbell, Moyed Miften, Lindsey Olsen, Priscilla Stumpf, Tracey Schefter, Karyn A Goodman, Bernard L Jones
PURPOSE: Stereotactic body radiation therapy (SBRT) for pancreatic cancer requires a skillful approach to deliver ablative doses to the tumor while limiting dose to the highly sensitive duodenum, stomach, and small bowel. Here, we develop knowledge-based artificial neural network dose models (ANN-DMs) to predict dose distributions that would be approved by experienced physicians. METHODS: Arc-based SBRT treatment plans for 43 pancreatic cancer patients were planned, delivering 30-33 Gy in five fractions...
October 10, 2017: Medical Physics
https://www.readbyqxmd.com/read/28993798/challenges-for-quality-assurance-of-target-volume-delineation-in-clinical-trials
#6
REVIEW
Amy Tien Yee Chang, Li Tee Tan, Simon Duke, Wai-Tong Ng
In recent years, new radiotherapy techniques have emerged that aim to improve treatment outcome and reduce toxicity. The standard method of evaluating such techniques is to conduct large scale multicenter clinical trials, often across continents. A major challenge for such trials is quality assurance to ensure consistency of treatment across all participating centers. Analyses from previous studies have shown that poor compliance and protocol violation have a significant adverse effect on treatment outcomes...
2017: Frontiers in Oncology
https://www.readbyqxmd.com/read/28987748/consequences-of-introducing-geometric-gtv-to-ctv-margin-expansion-in-dahanca-contouring-guidelines-for-head-and-neck-radiotherapy
#7
Christian Rønn Hansen, Jørgen Johansen, Eva Samsøe, Elo Andersen, Jørgen B B Petersen, Kenneth Jensen, Lisbeth J Andersen, Hella M B Sand, Anders S Bertelsen, Cai Grau
BACKGROUND AND PURPOSE: Defining margins around the Gross Tumour Volume (GTV) to create a Clinical Target Volume (CTV) for head and neck cancer radiotherapy has traditionally been based on presumed knowledge of anatomical routes of spread. However, using a concentric geometric expansion around the GTV may be more reproducible. The purpose of this study was to analyse the inter-observer consistency of geometric CTV delineation with adaptation for anatomical boundaries versus anatomically defined CTVs...
October 4, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28984165/target-definition-in-salvage-postoperative-radiotherapy-for-prostate-cancer-18f-fluorocholine-pet-ct-assessment-of-local-recurrence
#8
Osman El Kabbaj, Philippe Robin, David Bourhis, Gurvan Dissaux, Nicola Rosenfelder, Antoine Valeri, Georges Fournier, Pierre-Yves Salaun, Olivier Pradier, Jean-Pierre Malhaire, Ronan Abgral, Ulrike Schick
PURPOSE: Inadequate clinical target volume (CTV) definition is likely to be a major contributing factor to local recurrence (LR) rate after radiotherapy. Our aims were to identify sites of prostate cancer LR in biochemical recurrence post-prostatectomy using (18)F-Fluorocholine (18F-FCH) positron emission tomography/computed tomography (PET/CT) and to compare different CTV-delineation guidelines in a cohort of postoperative patients. MATERIAL AND METHODS: Thirty-six patients presenting with LR within the prostatic bed on 18F-FCH PET/CT between 10/2011 and 06/2016 were included in this retrospective study...
October 6, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28980445/dosimetric-effects-of-anatomical-changes-during-fractionated-photon-radiation-therapy-in-pancreatic-cancer-patients
#9
Astrid van der Horst, Antonetta C Houweling, Geertjan van Tienhoven, Jorrit Visser, Arjan Bel
Pancreatic tumors show large interfractional position variation. In addition, changes in gastrointestinal gas volumes and body contour take place over the course of radiation therapy. We aimed to quantify the effect of these anatomical changes on target dose coverage, for the clinically used fiducial marker-based patient position verification and, for comparison, also for simulated bony anatomy-based position verification. Nine consecutive patients were included in this retrospective study. To enable fraction dose calculations on cone-beam CT (CBCT), the planning CT was deformably registered to each CBCT (13-15 per patient); gas volumes visible on CBCT were copied to the deformed CT...
October 4, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28980392/utilizing-18f-fluoroethyl-l-tyrosine-positron-emission-tomography-in-high-grade-glioma-for-radiation-treatment-planning-in-patients-with-contraindications-to-mri
#10
Dasantha T Jaymanne, Sneha Kaushal, David Chan, Geoff Schembri, David Brazier, Dale Bailey, Helen Wheeler, Michael Back
INTRODUCTION: Patients with high grade glioma (HGG) and contraindications to magnetic resonance imaging (MRI) are dependent on contrast-enhanced computerized tomography (CT) scan imaging for radiation therapy (RT) target volume delineation. This study reviews the experience with the utilization of 18F-fluoroethyl-l-tyrosine positron emission tomography (FET-PET) to define residual disease post craniotomy and optimize RT planning. METHODS: Patients with HGG and a contraindication to MRI managed with radiation therapy between 2007 and 2015 were identified...
October 5, 2017: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/28978306/respiratory-gated-4d-contrast-enhanced-fdg-pet-ct-for-radiotherapy-planning-of-lower-oesophageal-carcinoma-feasibility-and-impact-on-planning-target-volume
#11
Andrew Scarsbrook, Gillian Ward, Patrick Murray, Rebecca Goody, Karen Marshall, Garry McDermott, Robin Prestwich, Ganesh Radhakrishna
BACKGROUND: To assess the feasibility and potential impact on target delineation of respiratory-gated (4D) contrast-enhanced (18)Fluorine fluorodeoxyglucose (FDG) positron emission tomography - computed tomography (PET-CT), in the treatment planning position, for a prospective cohort of patients with lower third oesophageal cancer. METHODS: Fifteen patients were recruited into the study. Imaging included 4D PET-CT, 3D PET-CT, endoscopic ultrasound and planning 4D CT...
October 4, 2017: BMC Cancer
https://www.readbyqxmd.com/read/28963779/automatic-segmentation-of-the-clinical-target-volume-and-organs-at-risk-in-the-planning-ct-for-rectal-cancer-using-deep-dilated-convolutional-neural-networks
#12
Kuo Men, Jianrong Dai, Yexiong Li
PURPOSE: Delineation of the clinical target volume (CTV) and organs at risk (OARs) is very important for radiotherapy but is time-consuming and prone to inter-observer variation. Here, we proposed a novel deep dilated convolutional neural network (DDCNN)-based method for fast and consistent auto-segmentation of these structures. METHODS: Our DDCNN method was an end-to-end architecture enabling fast training and testing. Specifically, it employed a novel multiple-scale convolutional architecture to extract multiple-scale context features in the early layers, which contain the original information on fine texture and boundaries and which are very useful for accurate auto-segmentation...
September 30, 2017: Medical Physics
https://www.readbyqxmd.com/read/28951759/focal-therapy-for-prostate-cancer-the-technical-challenges
#13
REVIEW
Annette Haworth, Scott Williams
Focal therapy for prostate cancer has been proposed as an alternative treatment to whole gland therapy, offering the opportunity for tumor dose escalation and/or reduced toxicity. Brachytherapy, either low-dose-rate or high-dose-rate, provides an ideal approach, offering both precision in dose delivery and opportunity for a highly conformal, non-uniform dose distribution. Whilst multiple consensus documents have published clinical guidelines for patient selection, there are insufficient data to provide clear guidelines on target volume delineation, treatment planning margins, treatment planning approaches, and many other technical issues that should be considered before implementing a focal brachytherapy program...
August 2017: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/28943074/local-protocol-variations-for-image-guided-radiation-therapy-in-the-multicenter-dutch-hypofractionation-hypro-trial-impact-of-rectal-balloon-and-mri-delineation-on-anorectal-dose-and-gastrointestinal-toxicity-levels
#14
R C Wortel, W D Heemsbergen, R J Smeenk, M G Witte, A D Krol, F J Pos, L Incrocci
PURPOSE: The phase 3 HYpofractionated irradiation for PROstate cancer (HYPRO) trial randomized patients with intermediate- to high-risk localized prostate cancer to conventionally fractionated (78 Gy in 39 fractions) or hypofractionated (64.6 Gy in 19 fractions) radiation therapy. Differences in techniques and treatment protocols were present between participating centers. This study aimed to compare dose parameters and patient-reported gastrointestinal symptoms between these centers...
August 3, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28941320/characteristics-of-the-local-recurrence-pattern-after-curative-resection-and-values-in-target-region-delineation-in-postoperative-radiotherapy-for-lower-thoracic-esophageal-squamous-cell-cancer
#15
Jun Liu, Xuwei Cai, Qi Liu, Hongxuan Li, Yan Cheng, Xiaolong Fu
BACKGROUND: The aim of this study was to investigate the patterns and influencing factors of local-regional recurrence of lower thoracic esophageal squamous cell carcinoma (TESCC) after curative resection and to delineate the clinical target volume (CTV) of postoperative radiotherapy (PORT). METHODS: From January 2009 to December 2013, the clinical data of patients who experienced local-regional recurrence after curative esophagectomy were collected and analyzed to determine local-regional recurrence patterns and to evaluate whether a proposed T-shaped PORT CTV could cover regions of local-regional failure...
September 23, 2017: Thoracic Cancer
https://www.readbyqxmd.com/read/28939178/prostate-cancer-post-prostatectomy-radiotherapy-ct-vs-mri-for-vesico-urethral-anastomosis-target-delineation
#16
Daryl Lim Joon, Adeline Lim, Michal Schneider, Chee-Yan Hiew, Nathan Lawrentschuk, Shomik Sengupta, Farshad Foroudi, Trish Jenkins, David Angus, Morikatsu Wada, Michael Chao, Vincent Khoo
BACKGROUND: Vesico-urethral anastomosis (VUA) is critical to the clinical target volume (CTV) in post-prostatectomy radiotherapy (PPRT), as it is the commonest site of recurrence. Typically, this is performed on a CT alone but guidelines recommend MRI. OBJECTIVE: To evaluate the VUA spatial differences between CT (ctVUA) and MRI (mrVUA) and analyse its impact on the CT defined CTV (ctCTV) as recommended by published guidelines. MATERIALS AND METHODS: We identified 34 patients with a co-registered simulation CT and T2 weighted MRI...
October 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28927030/implementation-of-diffusion-weighted-magnetic-resonance-imaging-in-target-delineation-of-central-lung-cancer-accompanied-with-atelectasis-in-precision-radiotherapy
#17
Xinli Zhang, Zheng Fu, Guanzhong Gong, Hong Wei, Jinghao Duan, Zhaoqiu Chen, Xiangming Chen, Ruozheng Wang, Yong Yin
Radiotherapy, particularly the target delineation of cancer based on scanned images, plays a key role in the planning of cancer treatment. Recently, diffusion-weighted magnetic resonance imaging (DW-MRI) has emerged as a prospective superior procedure compared with intensified computed tomography (CT) and positron emission tomography (PET) in the target delineation of cancer. However, the implication of DW-MRI in lung cancer, the leading cause of cancer-associated mortality worldwide, has not been extensively evaluated...
September 2017: Oncology Letters
https://www.readbyqxmd.com/read/28912110/the-genetics-of-congenitally-small-brains
#18
REVIEW
Sarah Duerinckx, Marc Abramowicz
Primary microcephaly (PM) refers to a congenitally small brain, resulting from insufficient prenatal production of neurons, and serves as a model disease for brain volumic development. Known PM genes delineate several cellular pathways, among which the centriole duplication pathway, which provide interesting clues about the cellular mechanisms involved. The general interest of the genetic dissection of PM is illustrated by the convergence of Zika virus infection and PM gene mutations on congenital microcephaly, with CENPJ/CPAP emerging as a key target...
September 11, 2017: Seminars in Cell & Developmental Biology
https://www.readbyqxmd.com/read/28886980/-dose-constraints-to-organs-at-risk-for-conformational-and-stereotactic-radiotherapy-small-bowel-and-duodenum
#19
REVIEW
F Goupy, E Chajon, J Castelli, É Le Prisé, L Duvergé, N Jaksic, G Vogin, É Monpetit, V Klein, L de Bosschère, P Maingon
Radiotherapy of abdominopelvic primary or secondary lesions in conformational or stereotactic techniques is in full development. The small bowel is highly sensitive to irradiation and is the main organ at risk limiting prescription doses. This literature review aims to define the dose constraints to the small bowel and the duodenum in conformational and stereotactic body radiotherapy. The small bowel including the duodenum, jejunum and ileum is delineated on the simulation scanner. The radio-induced intestinal toxicities are acute related to the cellular depopulation of the intestinal mucosa, and late of more complex pathophysiology associating depletion in stem cells, microangiopathy, chronic inflammation and fibrosis...
October 2017: Cancer Radiothérapie: Journal de la Société Française de Radiothérapie Oncologique
https://www.readbyqxmd.com/read/28885090/difference-in-target-definition-using-three-different-methods-to-include-respiratory-motion-in-radiotherapy-of-lung-cancer
#20
Ditte Sloth Møller, Marianne Marquard Knap, Tine Bisballe Nyeng, Azza Ahmed Khalil, Marianne Ingerslev Holt, Maria Kandi, Lone Hoffmann
INTRODUCTION: Minimizing the planning target volume (PTV) while ensuring sufficient target coverage during the entire respiratory cycle is essential for free-breathing radiotherapy of lung cancer. Different methods are used to incorporate the respiratory motion into the PTV. MATERIAL AND METHODS: Fifteen patients were analyzed. Respiration can be included in the target delineation process creating a respiratory GTV, denoted iGTV. Alternatively, the respiratory amplitude (A) can be measured based on the 4D-CT and A can be incorporated in the margin expansion...
September 8, 2017: Acta Oncologica
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