Investigating the utilization of beam-specific apertures for the intensity-modulated proton therapy (IMPT) head and neck cancer plans
Intensity-modulated proton therapy (IMPT) planning for the head and neck (HN) cancer often requires the use of the range shifter, which can increase the lateral penumbrae of the pencil proton beam in the patient, thus leading to an increase in unnecessary dose to the organs at risks (OARs) in proximity to the target volumes. The primary goal of the current study was to investigate the dosimetric benefits of utilizing beam-specific apertures for the IMPT HN cancer plans. The current retrospective study included computed tomography datasets of 10 unilateral HN cancer patients. (Source: Medical Dosimetry)
Source: Medical Dosimetry - November 24, 2020 Category: Radiology Authors: Suresh Rana, Mark Storey, Noufal Manthala Padannayil, Dayananda Sharma Shamurailatpam, Jaafar Bennouna, Jerry George, John Chang Source Type: research
The feasibility and efficacy of new SBRT technique HyperArc for recurrent nasopharyngeal carcinoma: noncoplanar cone-based robotic system vs. noncoplanar high-definition MLC based Linac system
The purpose of this study was to evaluate the feasibility and efficacy of HyperArc (HA) for recurrent nasopharyngeal cancer (NPC) by comparing it with the CyberKnife system (CK). Fifteen patients with recurrent nasopharyngeal cancer who were treated using the noncoplanar cone-based robotic CK system were enrolled. CK was delivered with a median dose of 37.5 Gy in 5 fractions. The delivered CK treatment plans were the sources for the corresponding homogeneous HA (HA-H) and inhomogeneous HA (HA-IH) plans. (Source: Medical Dosimetry)
Source: Medical Dosimetry - November 15, 2020 Category: Radiology Authors: Hsiu-Wen Ho, Ching-Chieh Yang, Hsiu-Man Lin, Hsiao-Yun Chen, Chun-Chiao Huang, Shih-Chang Wang, Yu-Wei Lin Source Type: research
Methods to optimize conformal dynamic arcs in radiation therapy treatment planning
Conformal Dynamic Arcs (CDA) can provide a useful alternative in certain clinical situations which require a higher level of 3-dimensional (3D) conformation than shaped static fields but for which modulated fields (fixed or arc) are inappropriate. Due to lack of modulation, the quality of the dose distribution produced by a CDA is highly dependent on the specific patient geometry. The ideal geometry for a CDA, in terms of achievable conformation and uniformity, is a spherical target perfectly centered in a cylindrical medium or body and utilizing a full 360 degree of rotation. (Source: Medical Dosimetry)
Source: Medical Dosimetry - November 7, 2020 Category: Radiology Authors: Caroline Kendra, Lon Marsh, Elaine Bogner, Benjamin Gielda Source Type: research
Characterization of 3D-printed bolus produced at different printing parameters
We aimed to analyze the effects of printing parameters on characterization of three-dimensional (3D) printed bolus used in external beam radiotherapy. Two sets of measurements were performed to investigate the dosimetric and physical characterization of 3D-printed bolus at different printing parameters. In the first step, boluses were produced at different infill-percentages, infill-patterns and printing directions. Two-dimensional (2D) dose measurements were performed in Elekta Versa HD linear accelerator using 6 MV photon energy. (Source: Medical Dosimetry)
Source: Medical Dosimetry - November 7, 2020 Category: Radiology Authors: Fatih Biltekin, Gozde Yazici, Gokhan Ozyigit Source Type: research
Investigation of approaches for internal target volume definition using 4-dimensional computed tomography in stereotactic body radiotherapy of lung cancer
The present study was undertaken to investigate the suitability of alternative internal target volume (ITV) delineation strategies based on maximum intensity projection (MIP), average intensity projection (AIP), 2 extreme phases and 4 phases images relative to the ITV10phase in stereotactic body radiation therapy (SBRT) for lung cancer. The 4-dimensional computed tomography (4DCT) data of 15 lung cancer patients treated with SBRT in our clinic were used. Five different ITVs were generated as follows: merging GTVs from 10 phases (ITV10Phase); merging GTVs from 2 extreme phases (0%, 50%) (ITV2Phase); merging GTVs from 4 phas...
Source: Medical Dosimetry - October 27, 2020 Category: Radiology Authors: Canan Koksal, Nazmiye Donmez Kesen, Murat Okutan, Sule Karaman, Nergiz Dagoglu Sakin, Hatice Bilge Source Type: research
Verification using in vivo optically stimulated luminescent dosimetry of the predicted skin surface dose in patients receiving postmastectomy radiotherapy
The purpose of this study was to evaluate whether dose to the skin surface underneath bolus, was accurately predicted by a 3D treatment planning system (TPS) in patients receiving 50 Gy/25# postmastectomy radiotherapy (PMRT) using optically stimulated luminescent dosimetry (OSLD) for verification. In vivo dosimetry using OSLDs was performed in 20 consecutive patients receiving PMRT. An array of 9 OSLDs were applied to the chest wall or neobreast in a grid arrangement. Dosimetry data were recorded on 3 separate treatment fractions, averaged, and extrapolated to 25 fractions. (Source: Medical Dosimetry)
Source: Medical Dosimetry - October 24, 2020 Category: Radiology Authors: Johnathon R. Wake, Feng Qin Chen, Simon Ashworth, Karen Byth, Wei Wang, Kirsty E. Stuart Source Type: research
A novel approach to embed eye shields in customized bolus on nasal dorsum treatment for electron radiotherapy
We aim to demonstrate the unique use of embedded lead eye shields in an electron wax bolus when treating the nasal dorsum. A patient presented to the clinic with squamous cell carcinoma of the nasal dorsum requiring treatment with en face electrons. A 3D customized wax bolus was designed and imported into the treatment planning system (TPS) to calculate the dose distribution. Due to high lens dose, the bolus was customized further to create 2 milled open slots in the wax, over the lens of eye, to allow lead sheets totaling 4 mm to be slid into the wax. (Source: Medical Dosimetry)
Source: Medical Dosimetry - October 21, 2020 Category: Radiology Authors: Xiao Wang, Beth Swann, Meral Reyhan, Ning J. Yue, Rachana Singh, Michael G. McKenna Source Type: research
Reduction of cardiac dose using respiratory-gated MR-linac plans for gastro-esophageal junction cancer
Treatment of locally advanced adenocarcinoma of the gastroesophageal junction (GEJ) with chemoradiation may be associated with high rates of symptomatic cardiac toxicity. Large margins are typically required to ensure coverage of GEJ tumors with free-breathing volumetric modulated arc therapy (VMAT) radiotherapy. The purpose of this study is to determine whether treatment with tighter margins enabled by maximum-inhalation breath hold (MIBH)-gated intensity modulated radiation therapy (IMRT) on an integrated MRI-linear accelerator system (MR-linac) can decrease radiation doses to the heart and cardiac substructures. (Source: Medical Dosimetry)
Source: Medical Dosimetry - October 20, 2020 Category: Radiology Authors: Sangjune Laurence Lee, Peter Mahler, Stephanie Olson, Jacob S. Witt, Hima Bindu Musunuru, Victoria Rajamanickam, Michael F. Bassetti, Poonam Yadav Source Type: research
Assessing tumor centrality in lung stereotactic ablative body radiotherapy (SABR): the effects of variations in bronchial tree delineation and potential for automated methods
Accurate delineation of the proximal bronchial tree (PBT) is crucial for appropriate assessment of lung tumor centrality and choice of Stereotactic Ablative Body Radiotherapy (SABR) dose prescription. Here, we investigate variabilities in manual PBT delineation and their potential to influence assessing lesion centrality. A fully automatic, intensity-based tool for PBT contouring and measuring distance to the target is also described. This retrospective analysis included a total of 61 patients treated with lung SABR. (Source: Medical Dosimetry)
Source: Medical Dosimetry - October 13, 2020 Category: Radiology Authors: Wsam Ghandourh, Jason Dowling, Phillip Chlap, Andrew Oar, Susannah Jacob, Vikneswary Batumalai, Lois Holloway Source Type: research
Continuous positive airway pressure with deep inspiration breath hold in left-sided breast radiation therapy
A dosimetric study to evaluate the use of continuous positive airway pressure (CPAP), with free-breathing (CPAP-FB) or with deep inspiration breath hold (DIBH-CPAP) an adjunct and alternative to DIBH to reduce heart and lung dose in the radiation therapy (RT) of breast cancer planned for left side RT with regional nodes and internal mammary. A retrospective analysis of 10 left-sided breast cancer patients whose heart or lung dose constraints were not met after RT planning based on FB or DIBH simulations and were referred for CPAP-based planning. (Source: Medical Dosimetry)
Source: Medical Dosimetry - October 1, 2020 Category: Radiology Authors: Jensen Reckhow, Orit Kaidar-Person, Merav A. Ben-David, Anna Ostrovski, Dina Ilinsky, Jeffrey Goldstein, Zvi Symon, Shira Galper Source Type: research
Dosimetric evaluation of image-guided radiation therapy for prostate cancer
Prostate cancer is the most common malignancy in North American males and the second leading cause of cancer death. External beam radiation therapy plays an important role in the clinical management of prostate cancer of various stages. Currently, image-guided target localization for intensity-modulated radiation therapy (IMRT) of prostate cancer has become a routine procedure, and plays an essential role in dose escalation and hypo-fractionation clinical trials, especially for those that employ stereotactic body radiation therapy (SBRT) techniques. (Source: Medical Dosimetry)
Source: Medical Dosimetry - October 1, 2020 Category: Radiology Authors: Guoping Shan, Wei Hu, Lili Chen, Robert A Price, C-M Charlie Ma Source Type: research
The robustness of VMAT radiotherapy for breast cancer with tissue deformations
To investigate the near-surface doses and target coverage in modulated arc radiotherapy (RT) of the breast or chest wall in two treatment planning systems (TPS) in the presence of soft tissue deformations. This retrospective study consisted of 10 breast cancer patients with axillary lymph node inclusion. For each case, five RT plans were created: (1) tangential 3D conformal field-in-field (FinF) technique; (2) 200 ° to 240° arcs with optimization bolus (OB) in Eclipse (EB); (3) 243° to 250° arcs with an 8-mm OB in Monaco (MB); (4) 243° to 250° arcs with automatic skin flash tool (ASF) in Monaco TPS (MA); (5) 243° to...
Source: Medical Dosimetry - September 25, 2020 Category: Radiology Authors: Maija Rossi, Tuomas Vir én, Janne Heikkilä, Jan Seppälä, Eeva Boman Tags: Dosimetry Contribution Source Type: research
Efficacy of MLC based cobalt ‐60 plans: A DVH comparison and analysis with 6 MV plans
The purpose of this study was to compare 3D treatment plans implemented using 6 MV Linac with a retrofitted multileaf collimator (MLC) based cobalt-60 plans. In this retrospective study, DVH analysis was used to compare homogeneity of dose within the target and the dose received by critical organs. A prototype MLC designed and developed as a retrofit to current cobalt-60 teletherapy machines with a dedicated 3D treatment planning system was used. Cases representing 5 tumor sites like head& neck, glottis, lung, gall bladder, stomach were taken for the study, which were planned using Eclipse treatment planning system and tre...
Source: Medical Dosimetry - September 25, 2020 Category: Radiology Authors: Akula Roopa Rani, Komanduri Ayyangar, A.R. Reddy, Ayyalasomayajula Anil Kumar, Pal Reddy Yadagiri Reddy Source Type: research
Efficacy of MLC based cobalt-60 plans: A DVH comparison and analysis with 6 MV plans
The purpose of this study was to compare 3D treatment plans implemented using 6 MV Linac with a retrofitted multileaf collimator (MLC) based cobalt-60 plans. In this retrospective study, DVH analysis was used to compare homogeneity of dose within the target and the dose received by critical organs. A prototype MLC designed and developed as a retrofit to current cobalt-60 teletherapy machines with a dedicated 3D treatment planning system was used. Cases representing 5 tumor sites like head& neck, glottis, lung, gall bladder, stomach were taken for the study, which were planned using Eclipse treatment planning system and tre...
Source: Medical Dosimetry - September 24, 2020 Category: Radiology Authors: Akula Roopa Rani, Komanduri Ayyangar, A.R. Reddy, Ayyalasomayajula Anil Kumar, Pal Reddy Yadagiri Reddy Source Type: research
New method for measurement of chest surface motion in lung cancer patients: Quantification using a technique of deformable image registration
The purpose of this study was to measure the motion of the chest surface during breath-holding treatment for lung cancer using deformable image registration (DIR). Forty non –small-cell lung cancer patients treated with breath-holding stereotactic body radiation therapy were retrospectively examined. First, intensity-based DIR between 2 breath-holding computed tomography (CT) images was performed. Subsequently, deformation vector field (DVF) for all dimensions (left-r ight, anterior-posterior, and superior-inferior) was calculated from the result. (Source: Medical Dosimetry)
Source: Medical Dosimetry - September 20, 2020 Category: Radiology Authors: Masahide Saito, Naoki Sano, Kengo Kuriyama, Takafumi Komiyama, Kan Marino, Shinichi Aoki, Yoshiyasu Maehata, Hidekazu Suzuki, Koji Ueda, Hiroshi Onishi Source Type: research
