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Dose calculation algorithms

Jing Dong, Guo-Hua Shi, Man Lu, Shu Huang, Yan-Hui Liu, Jia-Chen Yao, Wen-Yan Li, Long-Xuan Li
AIM: To evaluate the accuracy and predictive performance of Bayesian dosing for warfarin in Chinese patients. MATERIALS & METHODS: Six multiple linear regression algorithms (Wei, Lou, Miao, Huang, Gage and IWPC) and a Bayesian method implemented in Warfarin Dose Calculator were compared with each other. RESULTS: Six multiple linear regression warfarin dosing algorithms had similar predictive ability, except Miao and Lou. The mean prediction error of Bayesian priori and posteriori method were 0...
February 19, 2019: Pharmacogenomics
Nichole M Maughan, Jose Garcia-Ramirez, Matt Arpidone, Amy Swallen, Richard Laforest, S Murty Goddu, Parag J Parikh, Jacqueline E Zoberi
PURPOSE: Yttrium-90 (90 Y) microsphere radioembolization enables selective internal radiotherapy for hepatic malignancies. Currently, there is no standard post-delivery imaging and dosimetry of the microsphere distribution to verify treatment. Recent studies have reported utilizing the small positron yield of 90 Y (32 ppm) with PET to perform treatment verification and dosimetry analysis. In this study, we validated a commercial dosimetry software, MIM SurePlan™ LiverY90 (MIM Software Inc...
February 11, 2019: Medical Physics
Jihang Sun, Di Hu, Yun Shen, Haiming Yang, Chenghao Chen, Jie Yin, Yun Peng
OBJECTIVE: To evaluate model-based iterative reconstruction (MBIR) in improving the image quality of chest CT in children with reduced concentration contrast medium (CM). METHODS: Fifty-six children (median age of 4 years) who received low-dose enhanced chest CT were enrolled as the study group and compared with the control group of 56 children. Both groups used the automatic tube current modulation to achieve age-based noise index values of 11-15 HU. The study group used 100 kVp and reduced CM concentration of 270 mgI/ml, and the images in this group were reconstructed with 50% adaptive statistical iterative reconstruction (ASIR) and MBIR...
February 9, 2019: La Radiologia Medica
Kento Hoshida, Fujio Araki, Takeshi Ohno, Hirofumi Tominaga, Kazuki Komatsu, Kentaro Tamura
The purpose of this study was to verify the accuracy of dose calculation algorithms of a treatment planning system for a single-isocenter volumetric modulated arc therapy (VMAT) plan in multiple brain metastases, by comparing the dose distributions of treatment planning system with those of Monte Carlo (MC) simulations. We used a multitarget phantom containing 9 acrylic balls with a diameter of 15.9 mm inside a Lucy phantom measuring 17 × 17 × 17 cm3 . Seven VMAT plans were created using the multitarget phantom: 1 multitarget plan (MTP) and 6 single target plans (STP)...
February 6, 2019: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
Daniel Zucca Aparicio, Ovidio Hernando Requejo, Miguel Ángel de la Casa de Julián, Carmen Rubio Rodríguez, Pedro Fernández Letón
Aim: To evaluate dose differences in lung metastases treated with stereotactic body radiotherapy (SBRT), and the correlation with local control, regarding the dose algorithm, target volume and tissue density. Background: Several studies showed excellent local control rates in SBRT for lung metastases, with different fractionation schemes depending on the tumour location or size. These results depend on the dose distributions received by the lesions in terms of the tissue heterogeneity corrections performed by the dose algorithms...
March 2019: Reports of Practical Oncology and Radiotherapy
Ancor Sanz-Garcia, Miriam Perez-Romero, Jesus Pastor, Rafael G Sola, Lorena Vega-Zelaya, Gema Vega, Fernando Monasterio, Carmen Torrecilla, Paloma Pulido, Guillermo J Ortega
Sedation of neurocritically ill patients is one of the most challenging situation in ICUs. Quantitative knowledge on the sedation effect on brain activity in that complex scenario could help to uncover new markers for sedation assessment. Hence, we aim to evaluate the existence of changes of diverse EEG-derived measures in deeply-sedated (RASS -Richmond Agitation-Sedation Scale- -4 and -5) neurocritically ill patients, and also whether sedation doses are related with those eventual changes. 
 Approach: We performed an observational prospective cohort study in the Intensive Care Unit of the Hospital de la Princesa...
January 31, 2019: Journal of Neural Engineering
Xiaowei Ren, Jielai Xia
This study was inspired by the need to estimate pointwise confidence intervals (CIs) for a nonlinear dose-response model from a dose-finding clinical trial. Profile likelihood based CI for a nonlinear dose response model is often recommended. However, it is still not commonly used in dose-finding studies because it cannot generally be calculated explicitly. Most previous research has mainly focused on the performance of the profile likelihood based CI method compared with other common approaches. However, there are still no reports on computing profile likelihood based pointwise CIs for an entire dose-response curve...
2019: PloS One
Arun Gandhi, Subramani Vellaiyan, Shanmuga Subramanian, Shanmugam Thirumalai Swamy, Kala Subramanian, Anantharaman Ayyalusamy
Objective: The purpose of this study is to develop a method to estimate the dose using amorphous silicon detector panel cone beam computed tomography (aSi-kVCBCT) for the OARs and targets in prostate radiotherapy and to compare with the actual planned dose. Methods: The aSi-kVCBCT is used widely in radiotherapy to verify the patient position before treatment. The advancement in aSi-kVCBCT combined with adaptive software allows us to verify the dose distribution in daily acquired CBCT images. CBCT images from 10 patients undergoing radical prostate radiotherapy were included in this study...
January 25, 2019: Asian Pacific Journal of Cancer Prevention: APJCP
Eleftherios Tzanis, Dimitrios Tsetis, Elias Kehagias, Christos V Ioannou, John Damilakis
OBJECTIVES: The purpose of this study was to determine the radiation exposure of primary interventionalist's different body parts during endovascular aneurysm repair (EVAR) procedures and aortoiliac percutaneous transluminal angioplasty (PTA) procedures and to evaluate the efficacy of a radioprotective drape. METHODS: Occupational doses for 36 consecutive aortoiliac PTA procedures and 17 consecutive EVAR procedures were estimated using thermoluminescence dosimetry (TLD) chips (TLD-200, Hashaw, Solon, OH)...
January 23, 2019: La Radiologia Medica
Quan Chen, Janelle Molloy, Tadahide Izumi, Edmond Sterpin
The orthovoltage x-Ray energy frequently used in radiation research is prone to dosimetry errors due to insufficient backscatter conditions. In many radiobiology studies, especially for cell irradiations, precise dose calculation algorithms such as Convolution-Superposition or Monte Carlo are impractical and as such, less accurate hand calculation methods are used for dose estimation. These dose estimation methods typically assume full backscatter conditions. The purpose of this study is to demonstrate the magnitude of the dose error that results from insufficient backscatter, and to provide lookup tables to account this issue...
January 23, 2019: Physics in Medicine and Biology
Filipa Guerreiro, Lauri Koivula, Enrica Seravalli, Geert O Janssens, John H Maduro, Charlotte L Brouwer, Erik W Korevaar, Antje-Christin Knopf, Juha Korhonen, Bas W Raaymakers
The purpose of this study was to develop a method enabling synthetic computed tomography (sCT) generation of the whole abdomen using magnetic resonance imaging (MRI) images of pediatric patients with abdominal tumors. The proposed method relies on an automatic atlas-based segmentation of bone and lungs followed by an MRI intensity to synthetic Hounsfield unit conversion. Separate conversion algorithms were used for bone, lungs and soft-tissue. Rigidly registered CT and T2-weighted MR images of 30 patients in treatment position and with the same field of view were used for the evaluation of the atlas and the conversion algorithms...
January 22, 2019: Physics in Medicine and Biology
Oya Akyol, Bahar Dirican, Turkay Toklu, Hakan Eren, Turan Olgar
OBJECTIVES: The aim of this study was to investigate the effect of dental implant materials with different physical densities on dose distribution for head and neck cancer radiotherapy planning. METHODS: Titanium (Ti), Titanium alloy (Ti-6Al-4V), Zirconia (Y-TZP), Zirconium oxide (ZrO2 ), Alumina (Al2 O3 ) and polyetheretherketone (PEEK) dental implant materials were used for determination of implant material effect on dose distribution. Dental implant effect was investigated by using pencil beam convolution (PBC) algorithm of Eclipse treatment planning systems (TPS) and Monte Carlo (MC) simulation technique...
February 1, 2019: Dento Maxillo Facial Radiology
Fabian Krause, Franziska Risske, Susann Bohn, Marc Delaperriere, Jürgen Dunst, Frank-André Siebert
Purpose: One of the important developments in brachytherapy in recent years has been the clinical implementation of complex modern technical procedures. Today, 3D-imaging has become the standard procedure and it is used for contouring and precise position determination and reconstruction of used brachytherapy applicators. Treatment planning is performed on the basis of these imaging methods, followed by data transfer to the afterloading device. Therefore, checking the entire treatment chain is of high importance...
December 2018: Journal of Contemporary Brachytherapy
Vittorio Magri, Matteo Boltri, Tommaso Cai, Roberto Colombo, Salvatore Cuzzocrea, Pieter De Visschere, Rosanna Giuberti, Clara Maria Granatieri, Maria Agnese Latino, Gaetano Larganà, Christian Leli, Giorgio Maierna, Valentina Marchese, Elisabetta Massa, Alberto Matteelli, Emanuele Montanari, Giuseppe Morgia, Kurt G Naber, Vaia Papadouli, Gianpaolo Perletti, Nektaria Rekleiti, Giorgio I Russo, Alessandra Sensini, Konstantinos Stamatiou, Alberto Trinchieri, Florian M E Wagenlehner
The modern clinical research on prostatitis started with the work of Stamey and coworkers who developed the basic principles we are still using. They established the segmented culture technique for localizing the infections in the males to the urethra, the bladder, or the prostate and to differentiate the main categories of prostatitis. Such categories with slight modifications are still used according to the NIH classification: acute bacterial prostatitis, chronic bacterial prostatitis, Chronic Pelvic Pain Syndrome (CPPS) and asymptomatic prostatitis...
January 18, 2019: Archivio Italiano di Urologia, Andrologia
Zhanli Ren, Xirong Zhang, Zhijun Hu, Dou Li, Zhentang Liu, Donghong Wei, Yongjun Jia, Nan Yu, Yong Yu, Yuxin Lei, Xiaoxia Chen, Changyi Guo, Zhanliang Ren, Taiping He
OBJECTIVES: To explore the application of adaptive statistical iterative reconstruction-V (ASIR-V) with combination of 80 kV for reducing radiation dose and improving image quality in renal computed tomography angiography (CTA) for slim patients compared with traditional filtered back projection (FBP) reconstruction using 120 kV. METHODS: Eighty patients for renal CTA were prospectively enrolled and randomly divided into group A and group B. Group A used 120 kV and 600 mgI/kg contrast agent and FBP reconstruction, while group B used 80 kV and 350 mgI/kg contrast agent and both FBP and ASIR-V reconstruction from 10%ASIR-V to 100%ASIR-V with 10%ASIR-V interval...
January 15, 2019: Academic Radiology
Carla Winterhalter, Stefan Zepter, Sojin Shim, Gabriel Meier, Alessandra Bolsi, Anna Fredh, Jan Hrbacek, David Oxley, Ye Zhang, Damien Charles Weber, Antony John Lomax, Sairos Safai
For pencil beam scanned (PBS) proton therapy, analytical dose calculation engines are still typically used for the optimisation process, and often for the final evaluation of the plan. Recently however, the suitability of analytical calculations for planning PBS treatments has been questioned. Conceptually, the two main approaches for these analytical dose calculations are the ray-casting (RC) and the pencil-beam (PB) method. In this study, we compare dose distributions and dosimetric indices, calculated on both the clinical dose calculation grid and as a function of dose grid resolution, to Monte Carlo (MC) calculations...
January 14, 2019: Physics in Medicine and Biology
Zhenia Gopalakrishnan, Raghuram K Nair, P Raghukumar, Sharika V Menon, Saju Bhasi
Aim: The aim of this study is to measure and compare the surface dose of treated breast and contralateral breast with the treatment planning system (TPS) calculated dose using calibrated optically stimulated luminescent dosimeter (OSLD) in an indigenous wax breast phantom. Materials and Methods: Three-dimensional conformal plans were generated in eclipse TPS v. 13 to treat the left breast of a wax phantom for a prescribed dose of 200 cGy. The plans were calculated using anisotropic analytical algorithm (AAA) and Acuros algorithm with 1-mm grid size...
October 2018: Journal of Medical Physics
Senait Aknaw Debebe, Malek Adjouadi, Seza A Gulec, Juan Franquiz, Anthony J McGoron
INTRODUCTION: Yttrium-90 (90 Y) microsphere post-treatment imaging reflects the true distribution characteristics of microspheres in the tumor and liver compartments. However, due to its decay spectra profile lacking a pronounced photopeak, the bremsstrahlung imaging for 90 Y has inherent limitations. The absorbed dose calculations for 90 Y microspheres radiomicrosphere therapy (RMT) sustain a limitation due to the poor quality of 90 Y imaging. The aim of this study was to develop quantitative methods to improve the post-treatment 90 Y bremsstrahlung single photon emission tomography (SPECT)/computed tomography (CT) image analysis for dosimetric purposes and to perform a quantitative comparison with the 99m Tc-MAA SPECT/CT images, which is used for theranostics purposes for liver and tumor dosimetry...
January 9, 2019: Journal of Applied Clinical Medical Physics
Johann-Martin Hempel, Malte Niklas Bongers, Katharina Braun, Ulrike Ernemann, Georg Bier
BACKGROUND: The novel advanced modeled iterative reconstruction (ADMIRE) algorithm in ultra-high-resolution (UHR) computed tomography (CT) of the temporal bone has not yet been systematically evaluated. PURPOSE: To assess the potential of ADMIRE in temporal bone UHR CT. MATERIAL AND METHODS: Forty-four patients who underwent UHR CT of the temporal bone using z-axis UHR protocol were retrospectively selected for analysis. Images were reconstructed using filtered back projection (FBP) and ADMIRE with multiple strength levels...
January 8, 2019: Acta Radiologica
Milad Najafzadeh, Abolfzal Nickfarjam, Keyvan Jabbari, Daniel Markel, James C L Chow
OBJECTIVE: To evaluate the dose calculation accuracy in the Prowess Panther treatment planning system (TPS) using the collapsed cone convolution (CCC) algorithm. METHODS: The BEAMnrc Monte Carlo (MC) package was used to predict the dose distribution of photon beams produced by the Oncor ® linear accelerator (linac). The MC model of an 18 MV photon beam was verified by measurement using a p-type diode dosimeter. Percent depth dose (PDD) and dose profiles were used for comparison based on three field sizes: 5×5, 10×10, and 20×20cm2...
January 2, 2019: Journal of X-ray Science and Technology
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