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Radiotherapy error

Huanli Luo, Yanan He, Fu Jin, Dingyi Yang, Xianfeng Liu, Xueqi Ran, Ying Wang
Introduction: Accurate delineation of targets and organs at risk (OAR) is required to ensure treatment efficacy and minimize risk of normal tissue toxicity with radiotherapy. Therefore, we evaluated the impacts of computed tomography (CT) slice thickness and reconstruction methods on the volume and dose evaluations of targets and OAR. Patients and methods: Eleven CT datasets from patients with thoracic cancer were included. 3D images with a slice thickness of 2 mm (2-CT) were created automatically...
2018: Cancer Management and Research
Katharina Bell, Norbert Licht, Christian Rübe, Yvonne Dzierma
BACKGROUND: Modern radiotherapy offers the possibility of highly accurate tumor treatment. To benefit from this precision at its best, regular positioning verification is necessary. By the use of image-guided radiotherapy and the application of safety margins the influence of positioning inaccuracies can be counteracted. In this study the effect of additional imaging dose by set-up verification is compared with the effect of dose smearing by positioning inaccuracies for a collective of head-and-neck cancer patients...
October 1, 2018: Radiation Oncology
Foster Benjamin, Sindhu Kunal, Hepel Jaroslaw, Wazer David, Theresa Graves, Charu Taneja, Doreen Wiggins, Leonard Kara
PURPOSE: The BioZorb® (Therapeutics, Aliso Viejo, CA), is an implantable 3D bioabsorbable marker used for tumor bed volume (TBV) identification during postoperative radiotherapy (RT) planning. We aimed to calculate and compare RT TBVs between two cohorts managed with and without the device. METHODS AND MATERIALS: Breast cancer patients treated at XXXX between May 1, 2015 and April 30, 2016 were retrospectively reviewed and grouped based upon 3D bioabsorbable marker placement...
September 27, 2018: Practical Radiation Oncology
Yazid Belkacemi, Laurianne Colson-Durand, Maryse Fayolle-Campana, Pascale Pons, Amandine Rialland, Sylvie Bastuji-Garin, Quy Nguyen Hoang, Delphine Lerouge, Françoise Jaffré, Marc Bollet, David Azria
PURPOSE: Morbidity and mortality review (MMR) meetings in Radiotherapy (RT) departments aim to monitor radiation-induced toxicities and identify potential factors that may be correlated with their development and severity, particularly treatment planning errors. The aim of the PROUST Survey was to make an inventory of existing MMR procedures and to describe their procedures. MATERIALS AND METHODS: The link to the web-questionnaire of the PROUST survey was sent to 351 radiation oncologists working in 172 centers...
September 27, 2018: Practical Radiation Oncology
Kenta Ninomiya, Hidetaka Arimura, Motoki Sasahara, Yudai Kai, Taka-Aki Hirose, Saiji Ohga
This study aimed to investigate the feasibility of anatomical feature points for the estimation of prostate locations in the Bayesian delineation frameworks for prostate cancer radiotherapy. The relationships between the reference centroids of prostate regions (CPRs) (prostate locations) and anatomical feature points were explored, and the most feasible anatomical feature points were selected based on the smallest location estimation errors of CPRs and the largest Dice's similarity coefficient (DSC) between the reference and extracted prostates...
September 28, 2018: Radiological Physics and Technology
F M Prins, B Stemkens, L G W Kerkmeijer, M M Barendrecht, J C J de Boer, E P A Vonken, J J W Lagendijk, R H N Tijssen
PURPOSE: One of the major challenges in SBRT of RCC is internal motion during treatment. Previous literature has aimed on mitigating the effects of motion by expansion of treatment margins or respiratory tracking. Online MRI-guided radiotherapy has the potential to further improve the treatment of RCC by direct visualization of the tumor during treatment. The efficacy of two motion management techniques were assessed: tumor trailing and respiratory tracking. Simulation of a single-fraction MRI-based SBRT treatment was performed to quantify intrafraction motion and assess the efficacy of the different motion management strategies...
September 24, 2018: Practical Radiation Oncology
M Hillbrand, G Landry, S Ebert, G Dedes, E P Pappas, G Kalaitzakis, C Kurz, M Würl, F Englbrecht, O Dietrich, D Makris, E Pappas, K Parodi
Proton beams used for radiotherapy have potential for superior sparing of normal tissue, although range uncertainties are among the main limiting factors in the accuracy of dose delivery. The aim of this study was to benchmark an N-vinylpyrrolidone based polymer gel to perform three-dimensional measurement of geometric proton beam characteristics and especially to test its suitability as a range probe in combination with an anthropomorphic phantom. For single proton pencil beams as well as for 3×3cm2 mono-energy layers depth dose profiles, lateral dose distribution at different depths and proton range were evaluated in simple cubic gel phantoms at different energies from 75 to 115MeV and different dose levels...
September 21, 2018: Zeitschrift Für Medizinische Physik
Tung-I Tsai, Yaofeng Zhang, Zhigang Zhang, Gy-Yi Chao, Cheng-Chieh Tsai
BACKGROUND: Radiotherapy has serious side effects and thus requires prudent and cautious evaluation. However, obtaining protein expression profiles is expensive and timeconsuming, making it necessary to develop a theoretical and rational procedure for predicting the radiotherapy outcome for bladder cancer when working with limited data. OBJECTIVE: A procedure for estimating the performance of radiotherapy is proposed in this research. The population domain (range of the population) of proteins and the relationships among proteins are considered to increase prediction accuracy...
September 2018: Methods of Information in Medicine
Carlos Huerga, Luis Glaría, Pablo Castro, Luis Alejo, José Bayón, Eduardo Guibelalde
Positron emission tomography (PET) images have been incorporated into the radiotherapy process as a powerful tool to assist in the contouring of lesions, leading to the emergence of a broad spectrum of automatic segmentation schemes for PET images (PET-AS). However, not all proposed PET-AS algorithms take into consideration the previous steps of image preparation. PET image noise has been shown to be one of the most relevant affecting factors in segmentation tasks. This study demonstrates a nonlinear filtering method based on spatially adaptive wavelet shrinkage using three-dimensional context modelling that considers the correlation of each voxel with its neighbours...
September 2018: Physica Medica: PM
Yu Kumazaki, Shuichi Ozawa, Mitsuhiro Nakamura, Satoshi Kito, Toshiyuki Minemura, Hidenobu Tachibana, Teiji Nishio, Satoshi Ishikura, Yasumasa Nishimura
PURPOSE: The aim of this study was to develop an end-to-end postal audit test to examine the coincidence between the imaging isocenter and treatment beam isocenter of the image guided radiotherapy (IGRT) linac system for Japan Clinical Oncology Group (JCOG) trials, as a part of IGRT credentialing of institutions participating in JCOG trials. METHODS: We developed an end-to-end postal audit test to verify radiation positional errors associated with IGRT techniques...
September 2018: Physica Medica: PM
Takuji Tsubokura, Hideya Yamazaki, Koji Masui, Naomi Sasaki, Daisuke Shimizu, Gen Suzuki, Satoaki Nakamura, Kei Yamada, Koji Okihara, Takumi Shiraishi, Ken Yoshida, Tatsuyuki Nishikawa, Haruumi Okabe
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
September 20, 2018: Scientific Reports
Jing-Min Hwang, Jing-Yin Hung, Yi-Han Tseng, You-Kang Chang, Yu-Nong Wang, Chiou-Shiung Chang
Before delivering of intensity-modulated radiotherapy, kilo-voltage image-guidance radiotherapy is widely used in setup error correction and monitoring intra-fraction motion effectively. Accordingly, this study proposes and tests an image integration technique for observing intra-fraction motion during beam delivery, with the wider objective of reducing both image-guidance time and the dose delivered to normal breast tissue. The study sample comprised 33 female patients with breast cancer, and 241 sets of portal images acquired using a VARIAN aSi-1000 electronic portal imaging device...
September 17, 2018: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
Hongfei Sun, Kai Xie, Liugang Gao, Jianfeng Sui, Tao Lin, Xinye Ni
This study aimed to investigate the reliability of pseudo-computed tomography (pseudo-CT) imaging based on ultrasound (US) deformation fields under different binary masks in radiotherapy.We used 3-dimensional (3D) CT and US images, including those acquired during CT simulation positioning, and cone-beam CT (CBCT) and US images acquired 1 week after treating 3 patients with cervical cancer. Image data of 3 different layers were selected from the US images, and 3D CT images of each patient were selected. For US image registration, the following were created and applied: binary masks of the region of interest overlapping (ROIO) between the US image based on simulation positioning and US image for positioning verification, region of interest (ROI), whole overlapping (wholeO), and whole imaging region (whole)...
September 2018: Medicine (Baltimore)
Mallory C Glenn, Victor Hernandez, Jordi Saez, David S Followill, Rebecca M Howell, Julianne M Pollard, Shouhao Zhou, Stephen F Kry
Previous works indicate that intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) plans that are highly complex may produce more errors in dose calculation and treatment delivery. Multiple complexity metrics have been proposed and associated with IMRT QA results, but their relationships with plan performance using in situ dose measurements have not been thoroughly investigated. This study aimed to evaluate the relationships between IMRT treatment plan complexity and anthropomorphic phantom performance in order to assess the extent to which plan complexity is related to dosimetric performance in the IROC phantom credentialing program...
September 19, 2018: Physics in Medicine and Biology
Wenyong Tan, Yingjie Wang, Ming Yang, Richard A Amos, Weihao Li, Jianzeng Ye, Royle Gary, Weixi Shen, Desheng Hu
Background: To quantify the geometrical changes of each neck nodal level (NNL) and estimate the geometric planning target volume (PTV) margin during image-guided radiotherapy (IGRT) for nasopharyngeal cancer (NPC). Methods: Twenty patients with locally advanced NPC underwent one planning computed tomography (CTplan ) and 6 weekly repeat CT (CTrep ) scans during chemoradiotherapy. Each CTrep was rigidly registered to the CTplan . All the NNLs were manually delineated in each transverse CT section...
August 2018: Quantitative Imaging in Medicine and Surgery
Sophie C Huijskens, Irma W E M van Dijk, Jorrit Visser, Brian V Balgobind, D Te Lindert, Coen R N Rasch, Tanja Alderliesten, Arjan Bel
BACKGROUND: Interfractional organ position variation might differ for abdominal organs and this could have consequences for defining safety margins. Therefore, the purpose of this study is to quantify interfractional position variations of abdominal organs in children in order to investigate possible correlations between abdominal organs and determine whether position variation is location-dependent. METHODS: For 20 children (2.2-17.8 years), we retrospectively analyzed 113 CBCTs acquired during the treatment course, which were registered to the reference CT to assess interfractional position variation of the liver, spleen, kidneys, and both diaphragm domes...
September 12, 2018: Radiation Oncology
Supriya Jain, Karyn A Goodman
Assessing the quality of health care delivered is a priority across medical specialties, but it is particularly critical for radiation oncology, a field with rapid introduction of new technologies and treatment paradigms. Deviation from acceptable standards can lead to delivery of inferior therapies and medical errors that can directly compromise patient clinical outcome, thus leading to disparities in quality of care. Professional oncologic specialty societies often take ownership of standardizing best practices by issuing evidence-based disease-specific consensus guidelines...
September 7, 2018: Current Treatment Options in Oncology
Marcin Wierzbicki, Lindsay Mathew, Anand Swaminath
Lung stereotactic-body radiotherapy (SBRT) places additional requirements on targeting accuracy over standard approaches. In treatment planning, a tumour volume is geometrically expanded and the resulting planning target volume (PTV) is covered with the prescribed dose. This ensures full dose delivery despite various uncertainties encountered during treatment. We developed a retrospective technique for optimizing the PTV expansion for a patient population. The method relies on deformable image registration (DIR) of the planning CT to a treatment cone-beam CT (CBCT)...
October 2, 2018: Physics in Medicine and Biology
Doan Trang Nguyen, Jeremy Todd Booth, Vincent Caillet, Nicholas Hardcastle, Adam Briggs, Carol Haddad, Thomas Eade, Ricky T O'Brien, Paul J Keall
Increasing evidence shows that intrafraction tumour motion monitoring must include both six degrees of freedom (6DoF): 3D translations and 3D rotations. Existing real- time algorithms for 6DoF target motion estimation requires continuous intrafraction fluoroscopic imaging at high frequency, thereby exposing patients to additional high imaging dose. This paper presents the first method capable of 6DoF motion monitoring using intermittent 2D kV imaging and a continuous external respiratory signal.
 Method: Our approach is to optimise a state-augmented linear correlation model between an external signal and internal 6DoF motion...
September 5, 2018: Physics in Medicine and Biology
Emilia Palmér, Emilia Persson, Petra Ambolt, Christian Gustafsson, Adalsteinn Gunnlaugsson, Lars E Olsson
PURPOSE: Magnetic resonance imaging (MRI)-only radiotherapy is performed without computed tomography (CT). A synthetic CT (sCT) is used for treatment planning. The aim of this study was to develop a clinically feasible quality assurance (QA) procedure for sCT using the kV-cone beam CT (CBCT), in an MRI-only workflow for prostate cancer patients. MATERIAL AND METHOD: Three criteria were addressed; stability in Hounsfield Units (HUs), deviations in HUs between the CT and CBCT, and validation of the QA procedure...
September 4, 2018: Journal of Applied Clinical Medical Physics
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