Read by QxMD icon Read


Nicholas Ade, F C P du Plessis
The presence of metallic prostheses during external beam radiotherapy of malignancies in the pelvic region has the potential to strongly influence the dose distribution to the target and to tissue surrounded by the prostheses. This study systematically investigates the perturbation effects of unilateral titanium prosthesis on 6 and 15 MV photon beam dose distributions using Gafchromic EBT2 film measurements in a novel pelvic phantom made out of a stack of nylon slices. Comparisons were also made between the film data and dose calculations made on XiO and Monaco treatment planning systems...
July 25, 2017: Journal of Applied Clinical Medical Physics
Nicholas Hardcastle, Bradley M Oborn, Annette Haworth
Stereotactic body radiation therapy (SBRT) aims to deliver a highly conformal ablative dose to a small target. Dosimetric verification of SBRT for lung tumors presents a challenge due to heterogeneities, moving targets, and small fields. Recent software (M3D) designed for dosimetric verification of lung SBRT treatment plans using an advanced convolution-superposition algorithm was evaluated. Ten lung SBRT patients covering a range of tumor volumes were selected. 3D CRT plans were created using the XiO treatment planning system (TPS) with the superposition algorithm...
September 2016: Journal of Applied Clinical Medical Physics
F Salinas Aranda, V Suarez, S Arbiser, R Sansogne
PURPOSE: To implement an end-to-end QA test of the radiation therapy imaging, planning and delivery process, aimed to assess the dosimetric agreement accuracy between planned and delivered treatment, in order to identify and correct possible sources of deviation. To establish an internal standard for machine commissioning acceptance. METHODS: A test involving all steps of the radiation therapy: imaging, planning and delivery process was designed. The test includes analysis of point dose and planar dose distributions agreement between TPS calculated and measured dose...
June 2016: Medical Physics
A Molineu, S Kry, P Alvarez, N Hernandez, T Nguyen, D Followill
PURPOSE: To report the results of SRS phantom irradiations METHODS: Anthropomorphic SRS head phantoms were sent to institutions participating in NCI sponsored SRS clinical trials and institutions interested in verifying SRS treatment delivery. The phantom shell was purchased from Phantom Laboratory and altered to house dosimetry and imaging inserts. The imaging insert has 1.9 cm diameter spherical target. The dosimetry insert holds two TLD capsules and radiochromic film in the coronal and sagittal planes through the center of the target...
June 2016: Medical Physics
K Stuetzer, T Paessler, C Valentini, F Exner, J Thiele, T Hoelscher, M Krause, C Richter
PURPOSE: Retrospective calculation of the delivered proton dose in prostate cancer patients based on a unique dataset of daily CT images. METHODS: Inter-fractional motion in prostate cancer patients treated at our proton facility is counteracted by water-filled endorectal ballon and bladder filling protocol. Typical plans (XiO, Elekta Instruments AB, Stockholm) for 74 Gy(RBE) sequential boost treatment in 37 fractions include two series of opposing lateral double-scattered proton beams covering the respective iCTV...
June 2016: Medical Physics
G Lucconi, E Bentefour, S Deepak, G Janssens, K Weaver, M Moteabbed, H-M Lu
PURPOSE: The clinical commissioning of a workflow for pre-treatment range verification/adjustment for the head treatment of pediatric medulloblastoma patients, including dose monitoring during treatment. METHODS: An array of Si-diodes (DIODES Incorporated) is placed on the patient skin on the opposite side to the beam entrance. A "scout" SOBP beam, with a longer beam range to cover the diodes in its plateau, is delivered; the measured signal is analyzed and the extracted water equivalent path lengths (WEPL) are compared to the expected values, revealing if a range correction is needed...
June 2016: Medical Physics
Reham S Sherif, Ehab M Attalla, Wael M Elshemey, Noha G Madian
INTRODUCTION: There is a growing interest in the study of radiation-induced secondary cancer. The aim of this work is (i) to estimate the peripheral doses attributable to intensity modulated radiotherapy (IMRT) and mega-voltage cone beam computed tomography (MV-CBCT) for some organs at risk (OARs) which surround the target being treated (Nasopharynx) in paediatric patients. (ii) To estimate the risk of radiation-induced secondary cancers attributable to patient setup verification imaging dose using MV-CBCT for Nasopharyngeal Carcinoma (NPC) in paediatric patients and comparing it with that attributable to the therapeutic dose using IMRT...
June 2017: Journal of Medical Imaging and Radiation Oncology
Yasser S Soliman, M I El Gohary, M H Abdel Gawad, E A Amin, O S Desouky
Ferrous xylenol gel was evaluated as a dosimeter in verifications of treatment plans for treatments of female breast tumors in external-beam radiation therapy. The dosimeter was calibrated in a cubic wax phantom irradiated with 6 and 15MV beams of an Elekta clinical linear accelerator and then used for measurements of doses in an anthropomorphic phantom of a female torso, which mimicked female breasts after modified radical mastectomy and breast-conserving surgery. Doses measured with the gel in specific locations in the phantom were compared with values predicted by treatment plans created with the XiO treatment planning system (Elekta / IMPAQ) and with results of measurements with an IBA CC13 ionization chamber in the same locations...
February 2017: Applied Radiation and Isotopes
Katharina Frentzel, Harun Badakhshi
PURPOSE: To prevent a fatal transfusion-associated graft-versus-host disease, it is recommended to irradiate transfusion blood and blood components with ionizing radiation. Using x-rays from a linear accelerator of the radiotherapy department is an accepted alternative to gamma irradiation devices of the blood bank and to the orthovoltage units that are replacing the gamma irradiators today. However, the use of high energy x-rays may carry a potential risk of induced radioactivity. The objective of this study was to investigate the effect of two different energy levels, 6 and 18 MV, which are executed in routine clinical settings...
December 2016: Medical Physics
Jiajie Huang, Kejie Li, Michael Gribskov
While RNAs are well known to possess complex structures, functionally similar RNAs often have little sequence similarity. While the exact size and spacing of base-paired regions vary, functionally similar RNAs have pronounced similarity in the arrangement, or topology, of base-paired stems. Furthermore, predicted RNA structures often lack pseudoknots (a crucial aspect of biological activity), and are only partially correct, or incomplete. A topological approach addresses all of these difficulties. In this work we describe each RNA structure as a graph that can be converted to a topological spectrum (RNA fingerprint)...
2016: PloS One
Suresh Rana, ChihYao Cheng, Li Zhao, SungYong Park, Gary Larson, Carlos Vargas, Megan Dunn, Yuanshui Zheng
INTRODUCTION: The purpose of this study was to evaluate the dosimetric and radiobiological impact of intensity modulated proton therapy (IMPT) and RapidArc planning for high-risk prostate cancer with seminal vesicles. METHODS: Ten high-risk prostate cancer cases were included in this retrospective study. For each case, IMPT plans were generated using multiple field optimisation (MFO) technique (two fields) with XiO treatment planning system (TPS), whereas RapidArc plans were generated using double-arc technique (two full arcs) with Eclipse TPS...
March 2017: Journal of Medical Radiation Sciences
Nicholas Hardcastle, Bradley M Oborn, Annette Haworth
Stereotactic body radiation therapy (SBRT) aims to deliver a highly conformal ablative dose to a small target. Dosimetric verification of SBRT for lung tumors presents a challenge due to heterogeneities, moving targets, and small fields. Recent software (M3D) designed for dosimetric verification of lung SBRT treatment plans using an advanced convolution-superposition algorithm was evaluated. Ten lung SBRT patients covering a range of tumor volumes were selected. 3D CRT plans were created using the XiO treatment planning system (TPS) with the superposition algorithm...
September 8, 2016: Journal of Applied Clinical Medical Physics
Eric Pante
Dendrobrachia was proposed by Xian-Guan et al. (2006) as the name of a new phylum of entoproct-like animals from the Lower Cambrian (Yunnan Province, China). This name was however preoccupied by the octocoral Dendrobrachia Brook 1889, which position within the subclass Octocorallia is currently uncertain (Opresko and Bayer 1991; Berntson et al. 1999, 2001). Based on the principles of homonymy and priority (Articles 52 and 23, respectively; ICZN 1999), a substitute name for the entoproct Dendrobrachia is necessary, and I propose Dendrobrachion (based on the Greek brachion, for arm)...
May 4, 2016: Zootaxa
Ananda Giri Babu Alagar, Ganesh Kadirampatti Mani, Kaviarasu Karunakaran
Small fields smaller than 4 × 4 cm2 are used in stereotactic and conformal treatments where heterogeneity is normally present. Since dose calculation accuracy in both small fields and heterogeneity often involves more discrepancy, algorithms used by treatment planning systems (TPS) should be evaluated for achieving better treatment results. This report aims at evaluating accuracy of four model-based algorithms, X-ray Voxel Monte Carlo (XVMC) from Monaco, Superposition (SP) from CMS-Xio, AcurosXB (AXB) and analytical anisotropic algorithm (AAA) from Eclipse are tested against the measurement...
January 8, 2016: Journal of Applied Clinical Medical Physics
El Hassane Bentefour, Stefan Both, Shikui Tang, Hsiao-Ming Lu
This study explores the potential of cone-beam computed tomography (CBCT) for monitoring relative beam range variations due to daily changes in patient anatomy for prostate treatment by anterior proton beams. CBCT was used to image an anthropomorphic pelvic phantom, in eight sessions on eight different days. In each session, the phantom was scanned twice, first at a standard position as determined by the room lasers, and then after it was shifted by 10 mm translation randomly along one of the X, Y, or Z directions...
November 8, 2015: Journal of Applied Clinical Medical Physics
Suresh Rana, Yuanshui Zheng
The main purposes of this study are to: 1) evaluate the accuracy of XiO treatment planning system (TPS) for different dose calculation grid size based on head phan-tom measurements in uniform scanning proton therapy (USPT); and 2) compare the dosimetric results for various dose calculation grid sizes based on real computed tomography (CT) dataset of pediatric brain cancer treatment plans generated by USPT and intensity-modulated proton therapy (IMPT) techniques. For phantom study, we have utilized the anthropomorphic head proton phantom provided by Imaging and Radiation Oncology Core (IROC)...
September 8, 2015: Journal of Applied Clinical Medical Physics
Woo-Young Jeon, Hyeun-Kyoo Shin, In-Sik Shin, Sang Kyum Kim, Mee-Young Lee
BACKGROUND: Soshiho-tang, known as Xio-hai-Hu-Tang in Chinese and Sho-Saiko-to in Japanese, has been widely used as a therapeutic agent. Its pharmacological effects include anti-inflammatory, antioxidant, antihepatic fibrosis, antitumor and immunomodulating activities. However, little is known regarding its effects on allergic asthma. Therefore, the aim of the present study was to investigate whether the Soshiho-tang water extract (SSTW) has antiasthmatic effects on airway inflammation in an ovalbumin (OVA)-induced mouse model...
September 18, 2015: BMC Complementary and Alternative Medicine
Nan-zheng Zhang, Shuang Bai, Xiao-jun Cai, Li-bo Li
OBJECTIVE: To investigate the anti-tumor and immune efficacy of photodynamic immune-therapy (PIT), the combination of photodynamic therapy and dendritic cells (DC), on murine Heps hepatoma. METHODS: DCs were derived from syngeneic mouse bone marrow and then labeled with DAPI in vitro. The hepatoma model was established by subcutaneous inoculation with Heps cells in one hundred and twenty-eight mice. They were then divided into four groups at random: control group, PDT group, DC group and PIT group...
March 2016: Photodiagnosis and Photodynamic Therapy
T Underwood, D Giantsoudi, M Moteabbed, A Zietman, J Efstathiou, H Paganetti, H M Lu
PURPOSE: If a constant RBE of 1.1 is assumed, range-verified anterior oblique (AO) proton beams appear to offer the potential to reduce the mean dose delivered to the rectum, anterior rectal wall and penile bulb by a factor of ∼2 relative to standard bilateral (SB) proton beam arrangements. Additionally, AO proton beams targeted at the prostate avoid the femoral heads and so form a particularly appealing option for patients with hip prostheses. This study investigates LET enhancement at the distal edge of AO SOBPs, applying RBE models to consider the extent to which AO beams lead to hotspots in rectum biological dose...
June 2015: Medical Physics
J Xue, M Choi, J Park, T LaCouture, G Ibbott
PURPOSE: This work is to test the limitations of a photon dose algorithm during the commissioning of a treatment planning system. METHODS: Commissioning tests for a model-based dose calculation algorithm typically involve the verification of PDD, output and dose profiles, but often those tests are performed at one SSD, one depth and one nominal gantry position. Those tests are useful to validate the modeling of radiation beams, but they may not be sufficient to detect the limitations of an algorithm...
June 2015: Medical Physics
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"