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Journal of Applied Clinical Medical Physics

Yuting Li, Tucker Netherton, Paige L Nitsch, Song Gao, Ann H Klopp, Peter A Balter, Laurence E Court
PURPOSE: To evaluate the ability of the machine performance check (MPC) on the Halcyon to detect errors, with comparison with the TrueBeam. METHODS: MPC is an automated set of quality assurance (QA) tests that use a phantom placed on the couch and the linac's imaging system(s) to verify the beam constancy and mechanical performance of the Halcyon and TrueBeam linacs. In order to evaluate the beam constancy tests, we inserted solid water slabs between the beam source and the megavoltage imager to simulate changes in beam output, flatness, and symmetry...
July 17, 2018: Journal of Applied Clinical Medical Physics
Patrizia Urso, Rita Lorusso, Luca Marzoli, Daniela Corletto, Paolo Imperiale, Annalisa Pepe, Lorenzo Bianchi
Octavius® -4D is a very effective device in radiotherapy treatment quality assurance (QA), due to its simple set-up and analysis package. However, even if it is widely used, its main characteristics and criticalities were only partially investigated. Taking start from its commissioning, the aim of this work was to study the main dependencies of the device response. The outcome dependence was studied comparing results by different delivery techniques [Intensity Modulated Radiation Therapy, IMRT (n = 29) and RapidArc, RA (n = 15)], anatomical regions [15 head/neck, 19 pelvis and 10 pancreas] and linear accelerators [DHX (n = 14) and Trilogy (n = 30)]...
July 16, 2018: Journal of Applied Clinical Medical Physics
Xuanfeng Ding, Xiaoqiang Li, An Qin, Jun Zhou, Di Yan, Peter Chen, Chinnaiyan Prakash, Craig Stevens, Rohan Deraniyagala, Peyman Kabolizadeh
No abstract text is available yet for this article.
July 16, 2018: Journal of Applied Clinical Medical Physics
Peter K Taylor, Adam C Riegel
Several nomograms exist for ordering palladium-103 seeds for permanent prostate seed implants (PSI). Excess seeds from PSIs pose additional radiation safety risks and increase the cost of care. This study compared five nomograms to clinical data from dynamic modified-peripheral intraoperative PSI to determine (a) the cause of excess seeds and (b) the optimal nomogram for our institution. Pre- and intraoperative patient data were collected for monotherapy PSIs and compiled into a clinical database. All patients were prescribed 125 Gy with dose coverage of D90% = 100% to the planning target volume (PTV) using 103 Pd seeds with mean air-kerma strength (SK¯) of 2 U...
July 13, 2018: Journal of Applied Clinical Medical Physics
Giordano Biasi, Marco Petasecca, Susanna Guatelli, Ebert A Martin, Garry Grogan, Benjamin Hug, Jonathan Lane, Vladimir Perevertaylo, Tomas Kron, Anatoly B Rosenfeld
PURPOSE: The challenges of accurate dosimetry for stereotactic radiotherapy (SRT) with small unflattened radiation fields have been widely reported in the literature. In this case, suitable dosimeters would have to offer a submillimeter spatial resolution. The CyberKnife® (Accuray Inc., Sunnyvale, CA, USA) is an SRT-dedicated linear accelerator (linac), which can deliver treatments with submillimeter positional accuracy using circular fields. Beams are delivered with the desired field size using fixed cones, the InCise™ multileaf collimator or a dynamic variable-aperture Iris™ collimator...
July 12, 2018: Journal of Applied Clinical Medical Physics
Hann-Hsiang Chao, Gilmer Valdes, Jose M Luna, Marina Heskel, Abigail T Berman, Timothy D Solberg, Charles B Simone
BACKGROUND AND PURPOSE: Chest wall toxicity is observed after stereotactic body radiation therapy (SBRT) for peripherally located lung tumors. We utilize machine learning algorithms to identify toxicity predictors to develop dose-volume constraints. MATERIALS AND METHODS: Twenty-five patient, tumor, and dosimetric features were recorded for 197 consecutive patients with Stage I NSCLC treated with SBRT, 11 of whom (5.6%) developed CTCAEv4 grade ≥2 chest wall pain...
July 10, 2018: Journal of Applied Clinical Medical Physics
Seung Won Seol, Sonya Aggarwal, Rie von Eyben, Ziwei Wang, Cato Chan, Carmen Say, Lei Xing, Wendy Hara, Yong Yang, Quynh Thu Le
We prospectively investigated the feasibility of IMRT treatment plan optimization based on dosimeter measurements of lateral tongue mucosal dose adjacent to the dental fillings and evaluated dose-toxicity relationship and factors affecting oral mucositis (OM) in head and neck cancer patients. Twenty-nine head and neck cancer patients with metallic dental fillings who were scheduled to undergo fractionated external beam radiation therapy (RT) ± chemotherapy were enrolled. The lateral tongue dose was measured and if the calculated dose for the entire treatment was ≥35 Gy, a re-plan was generated to reduce the lateral tongue mucosal dose...
July 9, 2018: Journal of Applied Clinical Medical Physics
Kwang-Ho Cheong, Jai-Woong Yoon, Soah Park, Taejin Hwang, Sei-Kwon Kang, Taeryool Koo, Tae Jin Han, Haeyoung Kim, Me Yeon Lee, Kyoung Ju Kim, Hoonsik Bae
PURPOSE: The poor quality of megavoltage (MV) images from electronic portal imaging device (EPID) hinders visual verification of tumor targeting accuracy particularly during markerless tumor tracking. The aim of this study was to investigate the effect of a few representative image processing treatments on visual verification and detection capability of tumors under auto tracking. METHODS: Images of QC-3 quality phantom, a single patient's setup image, and cine images of two-lung cancer patients were acquired...
July 9, 2018: Journal of Applied Clinical Medical Physics
Tyler Meyer, Sarah Quirk, Malgorzata D'Souza, David Spencer, Michael Roumeliotis
PURPOSE: The objective of this work is to outline a framework for dosimetric characterization that will comprehensively detail the clinical commissioning steps for 3D-printed materials applied as patient support or immobilization devices in photon radiotherapy. The complex nature of 3D-printed materials with application to patient-specific configurations requires careful consideration. The framework presented is generalizable to any 3D-printed object where the infill and shell combinations are unknown...
July 8, 2018: Journal of Applied Clinical Medical Physics
Meijiao Wang, Sha Li, Yuliang Huang, Haizhen Yue, Tian Li, Hao Wu, Song Gao, Yibao Zhang
PURPOSE: To test if a RapidPlan DVH estimation model and its training plans can be improved interactively through a closed-loop evolution process. METHODS AND MATERIALS: Eighty-one manual plans (P0 ) that were used to configure an initial rectal RapidPlan model (M0 ) were reoptimized using M0 (closed-loop), yielding 81 P1 plans. The 75 improved P1 (P1+ ) and the remaining 6 P0 were used to configure model M1 . The 81 training plans were reoptimized again using M1 , producing 23 P2 plans that were superior to both their P0 and P1 forms (P2+ )...
July 8, 2018: Journal of Applied Clinical Medical Physics
Jonathan J Hindmarsh, Wendy L Smith
The existing two-story parkade is being replaced by a four-story parkade on a hospital campus. The parkade is across a two-lane access road from a cancer center with a nine-linear accelerator radiotherapy department in the basement. The new parkade is supported by over 280 drilled and cased pilings installed at depths between 10 and 25 m depending on the underlying soil strata and varying diameters, up to 1.5 m. The construction work in such close proximity to the radiation therapy department resulted in significant vibrations being felt in the simulation and treatment vaults...
July 7, 2018: Journal of Applied Clinical Medical Physics
Andrew Daudelin, David Medich, Syed Yasir Andrabi, Chris Martel
Modern CT systems seek to evaluate patient-specific dose by converting the CT dose index generated during a procedure to a size-specific dose estimate using conversion factors that are related to patient attenuation properties. The most accurate way to measure patient attenuation is to evaluate a full-field-of-view reconstruction of the whole scan length and calculating the true water-equivalent diameter (Dw ) using CT numbers; however, due to time constraints, less accurate methods to estimate Dw using patient geometry measurements are used more widely...
July 7, 2018: Journal of Applied Clinical Medical Physics
Maija Rossi, Eeva Boman, Tanja Skyttä, Mikko Haltamo, Marko Laaksomaa, Mika Kapanen
AIM: Traditional radiotherapy treatment techniques of the breast are insensitive for deformations and swelling of the soft tissue. The purpose of this study was to evaluate the dose changes seen with tissue deformations using different image matching methods when VMAT technique was used, and compare these with tangential technique. METHODS: The study included 24 patients with breast or chest wall irradiations, nine of whom were bilateral. In addition to planar kV setup imaging, patients underwent weekly cone-beam computed tomography (CBCT) imaging to evaluate soft tissue deformations...
July 5, 2018: Journal of Applied Clinical Medical Physics
Danielle Lack, Jian Liang, Lisa Benedetti, Cory Knill, Di Yan
PURPOSE: Data errors caught late in treatment planning require time to correct, resulting in delays up to 1 week. In this work, we identify causes of data errors in treatment planning and develop a software tool that detects them early in the planning workflow. METHODS: Two categories of errors were studied: data transfer errors and TPS errors. Using root cause analysis, the causes of these errors were determined. This information was incorporated into a software tool which uses ODBC-SQL service to access TPS's Postgres and Mosaiq MSSQL databases for our clinic...
July 5, 2018: Journal of Applied Clinical Medical Physics
Dingyi Zhou, Hong Quan, Di Yan, Shupeng Chen, An Qin, Carl Stanhope, Martin Lachaine, Jian Liang
PURPOSE: To investigate the intrafractional stability of the motion relationship between the diaphragm and tumor, as well as the feasibility of using diaphragm motion to estimate lung tumor motion. METHODS: Eighty-five paired (pre and posttreatment) daily 4D-CBCT images were obtained from 20 lung cancer patients who underwent SBRT. Bony registration was performed between the pre- and post-CBCT images to exclude patient body movement. The end-exhalation phase image of the pre-CBCT image was selected as the reference image...
July 3, 2018: Journal of Applied Clinical Medical Physics
Michael D Mills
No abstract text is available yet for this article.
July 1, 2018: Journal of Applied Clinical Medical Physics
Peter S Potrebko, Ravi Shridhar, Matthew C Biagioli, William F Sensakovic, George Andl, Jan Poleszczuk, Timothy H Fox
This work demonstrates the efficacy of voxel-based 90 Y microsphere dosimetry utilizing post-therapy SPECT/CT imaging and applies it to the prediction of treatment response for the management of patients with hepatocellular carcinoma (HCC). A 90 Y microsphere dosimetry navigator (RapidSphere) within a commercial platform (Velocity, Varian Medical Systems) was demonstrated for three microsphere cases that were imaged using optimized bremsstrahlung SPECT/CT. For each case, the 90 Y SPECT/CT was registered to follow-up diagnostic MR/CT using deformable image registration...
July 1, 2018: Journal of Applied Clinical Medical Physics
Natalie Pomerleau-Dalcourt, Parminder Basran
The Canadian Organization of Medical Physicists (COMP), in close partnership with the Canadian Partnership for Quality Radiotherapy (CPQR) has developed a series of Technical Quality Control (TQC) guidelines for radiation treatment equipment. These guidelines outline the performance objectives that equipment should meet in order to ensure an acceptable level of radiation treatment quality. The TQC guidelines have been rigorously reviewed and field tested in a variety of Canadian radiation treatment facilities...
July 1, 2018: Journal of Applied Clinical Medical Physics
Michael Roche, Robert Crane, Marcus Powers, Timothy Crabtree
The Monaco Monte Carlo treatment planning system uses three-beam model components to achieve accuracy in dose calculation. These components include a virtual source model (VSM), transmission probability filters (TPFs), and an x-ray voxel Monte Carlo (XVMC) engine to calculate the dose in the patient. The aim of this study was to assess the TPF component of the Monaco TPS and optimize the TPF parameters using measurements from an Elekta linear accelerator with an Agility™ multileaf collimator (MLC). The optimization began with all TPF parameters set to their default value...
June 30, 2018: Journal of Applied Clinical Medical Physics
Marguerite Tyran, Agnes Tallet, Michel Resbeut, Marjorie Ferre, Veronique Favrel, Pierre Fau, Laurence Moureau-Zabotto, Julien Dareon, Laurence Gonzague, Ahcene Benkemouche, Leonel Varela-Cagetti, Naji Salem, Bertrand Farnault, Marie-Aimee Acquaviva, Hugues Mailleux
PURPOSE: This study evaluates the benefit of a virtual bolus method for volumetric modulated arc therapy (VMAT) plan optimization to compensate breast modifications that may occur during breast treatment. METHODS: Ten files were replanned with VMAT giving 50 Gy to the breast and 47 Gy to the nodes within 25 fractions. The planning process used a virtual bolus for the first optimization, then the monitors units were reoptimized without bolus, after fixing the segments shapes...
June 30, 2018: Journal of Applied Clinical Medical Physics
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