OAR sparing 3D radiotherapy planning supported by fMRI brain mapping investigations
The human brain as an organ has numerous functions; some of them can be visualized by functional imaging techniques (e.g., functional MRI [fMRI] or positron emission tomography). The localization of the appropriate activity clusters requires sophisticated instrumentation and complex measuring protocol. As the inclusion of the activation pattern in modern self-tailored 3D based radiotherapy has notable advantages, this method is applied frequently. Unfortunately, no standardized method has been published yet for the integration of the fMRI data into the planning process and the detailed description of the individual applica...
Source: Medical Dosimetry - June 2, 2020 Category: Radiology Authors: G ábor Opposits, Csaba Aranyi, Csaba Glavák, Zsolt Cselik, Lajos Trón, Dávid Sipos, Janaki Hadjiev, Ervin Berényi, Imre Repa, Miklós Emri, Árpád Kovács Source Type: research
Robust treatment planning in whole pelvis pencil beam scanning proton therapy for prostate cancer
Whole-pelvis pencil beam scanning (PBS) proton therapy is utilized in both the intact and post-operative settings in patients with prostate cancer. As whole pelvis prostate radiotherapy has traditionally been delivered with standard photon beams, limited evidence and technical descriptions have been reported regarding the use of proton therapy. Here we present two robust three-field treatment planning approaches utilized to maximize target coverage in the presence of anatomic and delivery uncertainties. (Source: Medical Dosimetry)
Source: Medical Dosimetry - May 25, 2020 Category: Radiology Authors: Anish A. Butala, W. Scott Ingram, Shannon E. O'Reilly, Brett Hartl, Ali Kassaee, Curtiland Deville, Neha Vapiwala Source Type: research
Clinical evaluation of photon optimizer (PO) MLC algorithm for stereotactic, single-dose of VMAT lung SBRT
This report quantifies and compares the dosimetry and treatment delivery parameters of PO vs its predecessor progressive resolution optimizer (PRO) algorithm for a single-dose of volumetric modulated arc therapy (VMAT) lung stereotactic body radiation therapy (SBRT). Clinical SBRT treatment plans for 12 early-stage non –small-cell lung cancer patients receiving 30 Gy in 1 fraction using PRO-VMAT were re-optimized using the PO-VMAT MLC algorithm with identical planning parameters and objectives. (Source: Medical Dosimetry)
Source: Medical Dosimetry - May 18, 2020 Category: Radiology Authors: Justin Visak, Ronald C McGarry, Damodar Pokhrel Source Type: research
The degree of translational and rotational movement of implanted pacemakers and cardioverter-defibrillators on coronal plane images in patients treated with radiotherapy for lung malignancy
Malfunction of both implantable cardiac pacemakers and cardioverter-defibrillators as a result of exposure to therapeutic radiation is a known risk in radiation therapy. Although guidelines are available to minimize this risk for low energy beams, the guidelines rely on the estimated doses of ionizing radiation received by the device. Implicit in this calculation is that there is minimal day-to-day movement in the position of the device. However, with the exception of the leads in some cases, the devices are not intentionally sewn to the surrounding tissue but simply placed in a pocket in the prepectoral fascial compartmen...
Source: Medical Dosimetry - May 3, 2020 Category: Radiology Authors: Loukas A. Georgiou Source Type: research
Dosimetric and clinical advantages of adapting the DIBH technique to hybrid solitary dynamic portal radiotherapy for left-sided chest-wall plus regional nodal irradiation
To evaluate the dosimetric and clinical advantages of using deep-inspiration breath-hold (DIBH) technique in hybrid solitary dynamic portal radiotherapy (hSDPRT) for left-sided chest-wall plus regional nodal irradiation and to demonstrate a simplified strategy for preclinical commissioning and calibration of DIBH-gating technique. Fifteen patients with left-sided breast cancer who underwent postmastectomy radiotherapy using hSDPRT were retrospectively evaluated. Two sets of planning-CT images were acquired for each patient, one with free/normal breathing and the other with DIBH. (Source: Medical Dosimetry)
Source: Medical Dosimetry - May 2, 2020 Category: Radiology Authors: Kather Mohamathu Rafic, Solomon Patricia, Balasingh Timothy Peace, Christopher J. Sujith, Backianathan Selvamani, Paul B. Ravindran Source Type: research
The challenge of planning vertebral body SBRT: Optimizing target volume coverage
Stereotactic ablative body radiotherapy for vertebral metastases has been shown to be safe and effective to achieve tumor and pain control. To raise awareness of and build familiarity with vertebral stereotactic ablative body radiation therapy (SBRT) for a multicenter clinical trial including SBRT to vertebral metastases, Trans Tasman Radiation Oncology Cancer Research performed an international planning challenge. A single vertebral case was selected and the computed tomography image and contours were made available. (Source: Medical Dosimetry)
Source: Medical Dosimetry - April 11, 2020 Category: Radiology Authors: Nicholas Hardcastle, Fiona Bignell, Benjamin Nelms, Shankar Siva, Andrew Kneebone, Louis Lao, Olivia Cook, Monica Harris, John Shakeshaft Source Type: research
Atlas based segmentation in prone breast cancer radiation therapy
The evidence supporting atlas based contour generation is growing and includes breast, prostate, central nervous system, gastrointestinal, gynecologic, and head and neck cancer patient populations. We sought to investigate atlas based segmentation (ABS) in patients with early stage breast cancer status post breast conserving surgery treated with adjuvant radiation therapy in the prone position. An initial atlas library was generated by uploading 20 previously treated patients. Subsequently, a group of 20 consecutive patients underwent treatment planning. (Source: Medical Dosimetry)
Source: Medical Dosimetry - April 7, 2020 Category: Radiology Authors: William C. Stross, Steven M. Herchko, Laura A. Vallow Source Type: research
A dosimetric study using split x-jaw planning technique for the treatment of endometrial carcinoma
The aim of this retrospective study was to determine if the split x-jaw planning technique could be used with Varian linear accelerators to improve plan conformity and limit dose to organs at risk (OAR) for planning target volumes that require field sizes larger than the 15 cm extent of the multileaf collimator in the x-jaw position. Traditional planning techniques include limited and open x-jaw methods. The study population included 20 randomly selected patients with endometrial carcinoma. Treatment plans for each patient were designed using split, limited, and open x-jaw volumetric modulated arc radiotherapy for comparis...
Source: Medical Dosimetry - April 2, 2020 Category: Radiology Authors: Jeanette Keil, Joanne Carda, Jade Reihart, Marjorie Seidel, Nishele Lenards, Ashley Hunzeker Source Type: research
Exploiting tumor position differences between deep inspiration and expiration in lung stereotactic body radiation therapy planning
Purpose: We demonstrate proof of principle that normal tissue doses can be greatly reduced in lung stereotactic body radiation therapy (SBRT) for mobile tumors, if the delivered dose is split between opposite respiratory states. Methods: Patients that underwent 5 fraction lung SBRT at our institution and had deep inspiration breath hold (DIBH) and free breathing 4D computed tomography scans were included. Volumetric modulated arc therapy plans were generated on both respiratory phases and a third composite plan was generated delivering half the dose using the DIBH plan and the other half using the expiratory phase plan for...
Source: Medical Dosimetry - April 1, 2020 Category: Radiology Authors: Christina Huang, Kevin Shiue, Greg Bartlett, Namita Agrawal, Mona Arbab, Peter Maxim, Colleen DesRosiers, Todd Mereniuk, Susannah Ellsworth, Ryan Rhome, Jordan Holmes, Mark Langer, Richard Zellars, Tim Lautenschlaeger Source Type: research
Investigating the use of aperture shape controller in VMAT treatment deliveries
Background: Aperture shape controller (ASC) is a recently introduced leaf sequencer that controls the complexity of multileaf collimator apertures in the Photon Optimizer algorithm of the Eclipse treatment planning system. The aim of this study is to determine if the ASC can reduce plan complexity and improve verification results, without compromising plan quality. Methods: Thirteen plans grouped into cohorts of head and neck/brain, breast/chest and pelvis were reoptimised using the same optimization as the non-ASC setting for low, moderate and high ASC settings. (Source: Medical Dosimetry)
Source: Medical Dosimetry - March 25, 2020 Category: Radiology Authors: Diana Binny, Myles Spalding, Scott B. Crowe, David Jolly, Tanya Kairn, Jamie V. Trapp, Anthony Walsh Source Type: research
Dosimetric comparison of helical tomotherapy, volumetric-modulated arc therapy, intensity-modulated radiotherapy, and field-in-field technique for synchronous bilateral breast cancer
Purpose: To compare the dosimetric characteristics of helical tomotherapy (HT), volumetric-modulated arc therapy (VMAT), intensity-modulated radiotherapy (IMRT), and tangential field-in-field technique (FIF) for the treatment of synchronous bilateral breast cancer (SBBC). Methods and Materials: Ten patients with early-stage unilateral breast cancer were selected for simulating the patients with SBBC in this retrospective analysis. Treatment plans with HT, VMAT, IMRT, and FIF were generated for each patient with a total dose of 50.4 Gy in 28 fractions to the target. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 27, 2020 Category: Radiology Authors: Hao-Wen Cheng, Chih-Chieh Chang, An-Cheng Shiau, Ming-Hua Wang, Jo-Ting Tsai Source Type: research
Heart-sparing effect of postmastectomy radiotherapy for breast cancer patients: A dosimetric study of cardiac substructures
We investigated to what extent can the dose-volumes of the coronary artery and the cardiac substructures be reduced by using IMRT technique in left-sided breast cancer patients. We chose 40 pN2M0 patients treated with postmastectomy IMRT. The original treatment plans were retrieved and the (internal mammary nodes) IMNs and cardiac substructure delineations were added. Three sets of dose-volume parameters including the original plans without internal mammary irradiation (IMNI), the plans with IMNI, and the plans with dose constraints to the heart, were derived. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 24, 2020 Category: Radiology Authors: Fen Chen, Yee-Min Jen, Kui He, Zhaosheng Yin, Junwen Shi Source Type: research
Dosimetric evaluation of MR-derived synthetic-CTs for MR-only proton treatment planning
Purpose: To evaluate proton dose calculation accuracy of optimized pencil beam scanning (PBS) plans on MR-derived synthetic-CTs for prostate patients. Material and Methods: Ten patient datasets with both a CT and an MRI were planned with opposed lateral proton beams optimized to single field uniform dose under an IRB-approved study. The proton plans were created on CT datasets generated by a commercial synthetic CT-based software called MRCAT (MR for Calculating ATtenuation) routinely used in our clinic for photon-based MR-only planning. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 19, 2020 Category: Radiology Authors: David Aramburu N úñez, Sandra Fontenla, Lauren Rydquist, Gabriely Del Rosario, Zhiqiang Han, Chin-Cheng Chen, Dennis Mah, Neelam Tyagi Source Type: research
Evaluation of interbreath-hold lung tumor position reproducibility with vector volume histogram using the breath-hold technique
Tumor geometric reproducibility for lung stereotactic body radiotherapy (SBRT) is an important issue in the breath-hold (BH) technique. We investigated the inter-BH reproducibility of the tumor position in expiratory BH using our proposed vector volume histogram (VVH) method. Subjects comprising 14 patients with lung cancer who were treated with lung SBRT under expiratory BH conditions were monitored by the Abches system. Multiple computed tomography (CT) scans were performed to evaluate the inter-BH reproducibility of the tumor position at the expiratory BH in the simulation session. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 12, 2020 Category: Radiology Authors: Hideharu Miura, Shuichi Ozawa, Minoru Nakao, Yoshiko Doi, Katsumaro Kubo, Masahiko Kenjo, Yasushi Nagata Source Type: research
Confidence and proficiency levels of medical dosimetry graduates
The purpose of this study was to examine the confidence and proficiency levels of medical dosimetry graduates as they transition from student to professional during their first employment as medical dosimetrists. In addition, this study explored the support provided by employers to assist those medical dosimetry graduates during this transitional period. With assistance from the Medical Dosimetrist Certification Board (MDCB), individuals who graduated from a Joint Review Committee on Education in Radiologic Technology accredited medical dosimetry program between 2011 and 2018 and earned MDCB certification between 2012 and ...
Source: Medical Dosimetry - February 5, 2020 Category: Radiology Authors: Isaac D. Valdez, Kevin R. Clark Source Type: research
