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https://www.readbyqxmd.com/read/28092017/transanal-total-mesorectal-excision-for-a-large-leiomyosarcoma-at-the-lower-rectum-a-case-report-and-literature-review
#1
Nobuaki Hoshino, Koya Hida, Kenji Kawada, Takaki Sakurai, Yoshiharu Sakai
BACKGROUND: Rectal leiomyosarcoma (LMS) is an extremely rare disease. Previously, LMS was not properly distinguishable from gastrointestinal stromal tumor (GIST) until c-kit, a characteristic marker of GIST, was discovered in 1998. No standard therapeutic strategy for gastrointestinal LMS has been established except for surgical resection because of its rarity. Rectal LMS is often accompanied by symptoms, which can enable detection at a small size. However, when a large LMS is detected at the lower rectum, it is difficult to excise due to the narrow pelvic space...
December 2017: Surgical Case Reports
https://www.readbyqxmd.com/read/28089528/hydrogel-spacer-distribution-within-the-perirectal-space-in-patients-undergoing-radiotherapy-for-prostate-cancer-impact-of-spacer-symmetry-on-rectal-dose-reduction-and-the-clinical-consequences-of-hydrogel-infiltration-into-the-rectal-wall
#2
Benjamin W Fischer-Valuck, Anupama Chundury, Hiram Gay, Walter Bosch, Jeff Michalski
PURPOSE: Hydrogel prostate-rectum spacers, biomaterials placed between the prostate and rectum, continue to gain interest as a method to reduce or limit rectal dose during dose escalated prostate cancer radiation therapy. Because the spacer is initially injected into the perirectal space as a liquid, the final distribution can vary. The purpose of this study was to evaluate hydrogel spacer (SpaceOAR system) implantation and distribution from a recent prospective randomized control trial and correlate spacer symmetry with rectal dose reduction as well as rectal wall infiltration (RWI) to acute and late toxicity...
October 17, 2016: Practical Radiation Oncology
https://www.readbyqxmd.com/read/28047073/we-ab-209-11-prostate-cancer-treatment-planning-sensitivity-and-representative-objective-function-weights
#3
A Goli, J J Boutilier, T Craig, M B Sharpe, T C Y Chan
PURPOSE: To develop an automated planning methodology that exploits patient sensitivity to objective function weights. METHODS: Given a treatment plan, we first create an acceptable treatment region that encompasses a set of treatment plans with similar clinical performance (e.g., +/-1% at V70Gy). We use inverse optimization to map this region in criterion space to the weight space and find a corresponding region of acceptable weight vectors (W). The shape and size of W describes how sensitive a patient is to perturbations in objective function weights...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046556/we-ab-209-09-optimization-of-rotational-arc-station-parameter-optimized-radiation-therapy
#4
P Dong, B Ungun, S Boyd, L Xing
PURPOSE: To develop a fast optimization method for station parameter optimized radiation therapy (SPORT) and show that SPORT is capable of improving VMAT in both plan quality and delivery efficiency. METHODS: The angular space from 0° to 360° was divided into 180 station points (SPs). A candidate aperture was assigned to each of the SPs based on the calculation results using a column generation algorithm. The weights of the apertures were then obtained by optimizing the objective function using a state-of-the-art GPU based Proximal Operator Graph Solver (POGS) within seconds...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046285/su-g-tep1-09-modality-specific-dose-gradient-modeling-for-prostate-imrt-using-spherical-distance-maps-of-ptv-and-isodose-contours
#5
M M Folkerts, X Gu, W Lu, R J Radke, S B Jiang
PURPOSE: Overlapping volume histogram (OVH) and distance-to-target histogram (DTH) calculations rely on the assumption that dose gradients are symmetric with respect to primary target volume (PTV) expansion and minimum distance to PTV surface, respectively. It is desirable to lift this assumption and instead account for achievable modality-specific dose gradients (MSDG) for a given PTV shape. METHODS: From a library of 96 prostate 7-beam IMRT plans, we computed spherical distance maps (SDMs) for PTVs and 3 iso-dose contours...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/27991454/a-novel-method-for-interactive-multi-objective-dose-guided-patient-positioning
#6
Jonas Haehnle, Philipp Süss, Guillaume Landry, Katrin Teichert, Lucas Hille, Jan Hofmaier, Dimitri Nowak, Florian Kamp, Michael Reiner, Christian Thieke, Ute Ganswindt, Claus Belka, Katia Parodi, Karl-Heinz Küfer, Christopher Kurz
In intensity-modulated radiation therapy (IMRT), 3D in-room imaging data is typically utilized for accurate patient alignment on the basis of anatomical landmarks. In the presence of non-rigid anatomical changes, it is often not obvious which patient position is most suitable. Thus, dose-guided patient alignment is an interesting approach to use available in-room imaging data for up-to-date dose calculation, aimed at finding the position that yields the optimal dose distribution. This contribution presents the first implementation of dose-guided patient alignment as multi-criteria optimization problem...
January 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27587028/optimization-of-rotational-arc-station-parameter-optimized-radiation-therapy
#7
P Dong, B Ungun, S Boyd, L Xing
PURPOSE: To develop a fast optimization method for station parameter optimized radiation therapy (SPORT) and show that SPORT is capable of matching VMAT in both plan quality and delivery efficiency by using three clinical cases of different disease sites. METHODS: The angular space from 0° to 360° was divided into 180 station points (SPs). A candidate aperture was assigned to each of the SPs based on the calculation results using a column generation algorithm...
September 2016: Medical Physics
https://www.readbyqxmd.com/read/27317949/focal-or-whole-gland-salvage-prostate-brachytherapy-with-iodine-seeds-with-or-without-a-rectal-spacer-for-postradiotherapy-local-failure-how%C3%A2-best-to-spare-the-rectum
#8
Valentine Guimas, Magali Quivrin, Aurélie Bertaut, Etienne Martin, Damien Chambade, Philippe Maingon, Frédéric Mazoyer, Luc Cormier, Gilles Créhange
PURPOSE: Salvage prostate permanent implant (sPPI) for postradiation local failure provides high rates of biochemical control. The cumulative dose delivered to the prostate and the rectum is still unknown. METHODS AND MATERIALS: We reviewed the postimplant CT-based dosimetry of 18 selected patients who underwent sPPI with (125)I seeds for isolated biopsy-proven local failure several years after external beam radiation therapy. Ten patients had whole-prostate sPPI, and 8 patients had multiparametric MRI-based focal sPPI...
July 2016: Brachytherapy
https://www.readbyqxmd.com/read/27248158/implanted-spacer-approaches-for-pelvic-radiation-therapy
#9
Daniel M Trifiletti, Allison E Garda, Timothy N Showalter
INTRODUCTION: Recent clinical advances in radiation therapy have aimed to improve the therapeutic ratio through shortening the treatment duration through increasing the biologically effective dose (either through dose escalation or hypofractionation). However, despite using advanced techniques such as intensity modulated radiation therapy (IMRT) and image-guidance methods, dose escalation can be limited by its resultant gastrointestinal toxicity. In an effort to reduce rectal toxicity, biodegradable spacer materials and implantable balloons have been injected into the prostate-rectal space to increase the separation between the rectum and prostate thereby reducing rectal irradiation...
July 2016: Expert Review of Medical Devices
https://www.readbyqxmd.com/read/26998060/small-cell-carcinoma-of-the-rectum-a-report-of-imaging-results-from-four-cases
#10
Jian Zhou, Jingxian Shen, Huali Ma, Yun Zhang, Meili Sun, Lie Zheng, Yanchun Lv
Small cell carcinoma of the rectum is extremely rare. The present study aimed to improve the recognition of computed tomography (CT) and magnetic resonance imaging (MRI) features observed in patients with small cell carcinoma of the rectum. A total of 4 cases of patients with histologically confirmed small cell carcinoma of the rectum were retrospectively reviewed. The imaging features assessed consisted of the thickening of the rectal wall, local tumor invasion, CT density, MRI signal intensity, lesion texture, contrast enhancement characteristics, lymphadenopathy and distant metastasis...
March 2016: Oncology Letters
https://www.readbyqxmd.com/read/26853354/polyethylene-glycol-hydrogel-rectal-spacer-implantation-in-patients-with-prostate-cancer-undergoing-combination-high-dose-rate-brachytherapy-and-external-beam-radiotherapy
#11
Jekwon Yeh, Brandon Lehrich, Carolyn Tran, Albert Mesa, Ruben Baghdassarian, Jeffrey Yoshida, Robert Torrey, Michael Gazzaniga, Alan Weinberg, Stuart Chalfin, John Ravera, Kenneth Tokita
PURPOSE: To present rectal toxicity rates in patients administered a polyethylene glycol (PEG) hydrogel rectal spacer in conjunction with combination high-dose-rate brachytherapy and external beam radiotherapy. METHODS AND MATERIALS: Between February 2010 and April 2015, 326 prostate carcinoma patients underwent combination high-dose-rate brachytherapy of 16 Gy (average dose 15.5 Gy; standard deviation [SD] = 1.6 Gy) and external beam radiotherapy of 59.4 Gy (average dose 60...
May 2016: Brachytherapy
https://www.readbyqxmd.com/read/26668614/use-of-a-correlation-analysis-model-in-the-optimization-of-intensity-modulated-radiotherapy-of-prostate-cancer
#12
Xiadong Li, Qinghua Deng, Shenglin Ma, K E Zhang, Zhibing Wu, Jianjun Lai, Rongjun Tang, Yao Ren, Jiahao Wang, Lixia Xu
The aim of the present study was to develop a statistical model-based method for the optimization of intensity-modulated radiotherapy (IMRT). A prostate cancer IMRT plan was redesigned while retaining the same beam orientation and prescribed dose as the regular plan. A series of dosimetric parameters were generated, and a 4-step protocol was performed to analyze the data: i) The tumor control probability of the target was ensured by setting a number of strict constraint parameters so that much of the target was covered by the 95% isodose line; ii) the parameters for optimization [weight ratio, equivalent characteristic parameter a and maximum equivalent uniform dose of the organ at risk (OAR)] were adjusted; iii) the overall optimization space (OOS) was determined via analysis of the dose-parameter tables based on the correlation factor (CF) and optimization efficiency factor analysis; iv) the OOS in the Pinnacle V7...
December 2015: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/26622227/reduced-dose-to-urethra-and-rectum-with-the-use-of-variable-needle-spacing-in-prostate-brachytherapy-a-potential-role-for-robotic-technology
#13
Shilpa Vyas, Yi Le, Zhe Zhang, Woody Armour, Daniel Y Song
PURPOSE: Several robotic delivery systems for prostate brachytherapy are under development or in pre-clinical testing. One of the features of robotic brachytherapy is the ability to vary spacing of needles at non-fixed intervals. This feature may play an important role in prostate brachytherapy, which is traditionally template-based with fixed needle spacing of 0.5 cm. We sought to quantify potential reductions in the dose to urethra and rectum by utilizing variable needle spacing, as compared to fixed needle spacing...
August 2015: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/26581150/automatic-substitute-computed-tomography-generation-and-contouring-for-magnetic-resonance-imaging-mri-alone-external-beam-radiation-therapy-from-standard-mri-sequences
#14
Jason A Dowling, Jidi Sun, Peter Pichler, David Rivest-Hénault, Soumya Ghose, Haylea Richardson, Chris Wratten, Jarad Martin, Jameen Arm, Leah Best, Shekhar S Chandra, Jurgen Fripp, Frederick W Menk, Peter B Greer
PURPOSE: To validate automatic substitute computed tomography CT (sCT) scans generated from standard T2-weighted (T2w) magnetic resonance (MR) pelvic scans for MR-Sim prostate treatment planning. PATIENTS AND METHODS: A Siemens Skyra 3T MR imaging (MRI) scanner with laser bridge, flat couch, and pelvic coil mounts was used to scan 39 patients scheduled for external beam radiation therapy for localized prostate cancer. For sCT generation a whole-pelvis MRI scan (1...
December 1, 2015: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/26328206/the-transrectal-single-port-laparoscopic-radical-prostatectomy-in-a-cadaver-model
#15
Oktay Akça, Homayoun Zargar, Riccardo Autorino, Luis Felipe Brandao, Ahmet Selçuk Gürler, Abdullah Avşar, Rahim Horuz, Selami Albayrak
OBJECTIVE: To explore the feasibility of laparoscopic trans-rectal Natural Orifice Transluminal Endoscopic Surgery (NOTES) radical prostatectomy in a cadaveric model and to define anatomical landmarks of this surgical route. MATERIALS AND METHODS: After the ethical clearance, the study was conducted in Turkish Council of Forensic Medicine. With the cadaver in an exaggerated lithotomy position, a full thickness incision was made on the anterior wall of the rectum...
June 2015: Turkish Journal of Urology
https://www.readbyqxmd.com/read/26232692/diclofenac-suppository-as-a-preemptive-analgesia-in-ultrasound-guided-biopsy-of-prostate-randomized-controlled-trial
#16
RANDOMIZED CONTROLLED TRIAL
Naveed Haroon, M Hammad Ather, Salma Khan, Pirkash Kumar, Basit Salam
OBJECTIVE: To compare preprocedure Diclofenac suppository and Xylocaine gel with Xylocaine gel only in patients undergoing transrectal ultrasound (TRUS)-guided biopsy of prostate for pain. MATERIALS AND METHODS: It is a randomized controlled trial conducted on patients undergoing TRUS-guided biopsy for clinical or biochemical suspicion of prostate cancer following a written informed consent and Ethics Review Committee approval. Patients were randomized into 2 groups...
October 2015: Urology
https://www.readbyqxmd.com/read/26232129/comparison-of-two-different-rectal-spacers-in-prostate-cancer-external-beam-radiotherapy-in-terms-of-rectal-sparing-and-volume-consistency
#17
COMPARATIVE STUDY
Frank Wolf, Christoph Gaisberger, Ingrid Ziegler, Elisabeth Krenn, Philipp Scherer, Stephan Hruby, Tobias Schätz, Rosemarie Forstner, Josef Holzinger, Andrea Vaszi, Gerhard Kametriser, Philipp Steininger, Heinz Deutschmann, Felix Sedlmayer
BACKGROUND AND PURPOSE: In external beam radiation (EBRT) of the prostate, the rectum is the dose-limiting organ at risk, and sparing of the anterior rectal wall is a prerequisite for safe delivery of doses beyond 70 Gy. Spatial sparing of the rectum can be achieved by introducing a spacer material into the retroprostatic space, thus separating the anterior rectal wall from the PTV. MATERIALS AND METHODS: Two spacer technologies, Spacer OAR, a polyethylene glycol gel and ProSpace, a saline inflated balloon, were compared in terms of spacer volume, stability, and dose reduction to the anterior rectum wall in 78 patients...
August 2015: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/26198656/an-image-based-method-to-quantify-biomechanical-properties-of-the-rectum-in-radiotherapy-of-prostate-cancer
#18
Oscar Casares-Magaz, Maria Thor, Donghua Liao, Jens B Frøkjær, Pia Kræmer, Klaus Krogh, Asbjørn M Drewes, Hans Gregersen, Vitali Moiseenko, Morten Høyer, Ludvig P Muren
BACKGROUND: Gastrointestinal morbidity after radiotherapy (RT) for prostate cancer may be related to the biomechanical properties of the rectum. In this study we present a magnetic resonance imaging (MRI)-based method to quantitate the thickness and elasticity of the rectal wall in prostate cancer patients treated with RT. MATERIAL AND METHODS: Four patients previously treated with RT for prostate cancer underwent an MRI session with stepwise rectal bag deflation (from a maximum tolerable volume to 0 ml, in 50 ml steps), with a probe inserted inside the bag to monitor the internal rectal pressure...
2015: Acta Oncologica
https://www.readbyqxmd.com/read/26136612/optimization-of-light-sources-for-prostate-photodynamic-therapy
#19
Martin D Altschuler, Timothy C Zhu, Jun Li, Stephen M Hahn
To deliver uniform photodynamic dose to the prostate gland, it is necessary to develop algorithms that optimize the location and strength (emitted power × illumination time) of each light source. Since tissue optical properties may change with time, rapid (almost real-time) optimization is desirable. We use the Cimmino algorithm because it is fast, linear, and always converges reliably. A phase I motexafin lutetium (MLu)-mediated photodynamic therapy (PDT) protocol is on-going at the University of Pennsylvania...
April 22, 2005: Proceedings of SPIE
https://www.readbyqxmd.com/read/26054865/hydrogel-spacer-prospective-multicenter-randomized-controlled-pivotal-trial-dosimetric%C3%A2-and-clinical-effects-of-perirectal-spacer-application-in-men-undergoing-prostate%C3%A2-image-guided-intensity-modulated-radiation%C3%A2-therapy
#20
RANDOMIZED CONTROLLED TRIAL
Neil Mariados, John Sylvester, Dhiren Shah, Lawrence Karsh, Richard Hudes, David Beyer, Steven Kurtzman, Jeffrey Bogart, R Alex Hsi, Michael Kos, Rodney Ellis, Mark Logsdon, Shawn Zimberg, Kevin Forsythe, Hong Zhang, Edward Soffen, Patrick Francke, Constantine Mantz, Peter Rossi, Theodore DeWeese, Daniel A Hamstra, Walter Bosch, Hiram Gay, Jeff Michalski
PURPOSE: Perirectal spacing, whereby biomaterials are placed between the prostate and rectum, shows promise in reducing rectal dose during prostate cancer radiation therapy. A prospective multicenter randomized controlled pivotal trial was performed to assess outcomes following absorbable spacer (SpaceOAR system) implantation. METHODS AND MATERIALS: Overall, 222 patients with clinical stage T1 or T2 prostate cancer underwent computed tomography (CT) and magnetic resonance imaging (MRI) scans for treatment planning, followed with fiducial marker placement, and were randomized to receive spacer injection or no injection (control)...
August 1, 2015: International Journal of Radiation Oncology, Biology, Physics
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