Improving organ at risk sparing in oropharyngeal treatment planning by increasing target dose heterogeneity: A feasibility study
This study sought to determine the feasibility of allowing an increase in target dose heterogeneity in oropharyngeal VMAT plans, and to examine the dosimetric impact this has on target coverage and OARs such as the parotid glands, spinal cord, brainstem and mandible. (Source: Medical Dosimetry)
Source: Medical Dosimetry - April 14, 2021 Category: Radiology Authors: Rachel Barry, Elizabeth Forde, Sarah Barrett Source Type: research

Early-onset Symptomatic Radiation Necrosis After Stereotactic Radiosurgery in the Setting of COVID-19 Infection
Radiation necrosis (RN) is the primary dose-limiting treatment-related toxicity following stereotactic radiosurgery (SRS) and occurs in approximately 5-10% of patients with brain metastasis, [1] but is rarely described in patients with benign tumors given the lower doses prescribed for treatment. Several factors have been associated with risk of RN including multiple dose-volume metrics, prior radiotherapy, time from treatment, concurrent systemic therapies, certain regions of the brain parenchyma, histology of the tumor, etc. (Source: Medical Dosimetry)
Source: Medical Dosimetry - April 12, 2021 Category: Radiology Authors: Eduardo Weltman, Rupesh Kotecha Tags: Clinical Case Study Source Type: research

Evaluation of treatment plan quality for head and neck IMRT: a multicenter study
This study assessed the performance of IMRT planning in Malaysia and observed plan quality variation among participating centers. The computed tomography dataset containing contoured target volumes and OAR was provided to participating centers. (Source: Medical Dosimetry)
Source: Medical Dosimetry - April 7, 2021 Category: Radiology Authors: Diyana Afrina Hizam, Wei Loong Jong, Hafiz Mohd Zin, Kwan Hoong Ng, Ngie Min Ung Source Type: research

Challenges in lung and heart avoidance for postmastectomy breast cancer radiotherapy: Is automated planning the answer?
Postmastectomy radiotherapy (PMRT) has been shown to improve the overall survival for invasive breast cancer patients. However, it represents a challenging treatment geometry and individualized planning strategies with complex field arrangements are usually adopted to decrease radiotoxicity to heart and lungs. Automated treatment planning has the potential to improve plan quality consistency and planning efficiency. Herein, we describe the application of the Pinnacle3 Autoplanning engine as a valuable technological resource able to allow the treatment of challenging patients theoretically unfit for radiotherapy for major c...
Source: Medical Dosimetry - April 6, 2021 Category: Radiology Authors: Savino Cilla, Gabriella Macchia, Carmela Romano, Vittoria Emanuela Morabito, Mariangela Boccardi, Vincenzo Picardi, Vincenzo Valentini, Alessio Giuseppe Morganti, Francesco Deodato Source Type: research

Daily online adaptive magnetic resonance image (MRI) guided stereotactic body radiation therapy for primary renal cell cancer
Stereotactic body radiotherapy (SBRT) has demonstrated promising outcomes for patients with early-stage, medically inoperable, primary renal cell carcinoma (RCC) in large multi-institutional studies and prospective clinical trials. The traditional approach used in these studies consisted of a CT-based planning approach for target and organ-at-risk (OAR) volume delineation, treatment planning, and daily treatment delivery. Alternatively, MRI-based approaches using daily online adaptive radiotherapy have multiple advantages to improve treatment outcomes: (1) more accurate delineation of the target volume and OAR volumes with...
Source: Medical Dosimetry - April 1, 2021 Category: Radiology Authors: Tugce Kutuk, James McCulloch, Kathryn E. Mittauer, Tino Romaguera, Diane Alvarez, Alonso N. Gutierrez, Michael Chuong, Rupesh Kotecha Source Type: research

Whole brain radiotherapy with hippocampal sparing using Varian HyperArc
The purpose of this work was to evaluate using Varian HyperArc as a planning and treatment solution for whole brain radiotherapy (WBRT) with hippocampal sparing following Radiation Therapy Oncology Group (RTOG) 0933 dosimetric criteria. Ten patients previously treated for intracranial lesions were retrospectively planned for WBRT with hippocampal sparing using HyperArc and a 2-arc coplanar VMAT technique. The whole brain and hippocampus were delineated on fused MRI and CT datasets. The planning target volume (PTV), defined as the whole brain excluding the hippocampal avoidance region, was prescribed 30 Gy in 10 fractions. ...
Source: Medical Dosimetry - March 23, 2021 Category: Radiology Authors: Cameron J. Sprowls, Amish P. Shah, Patrick Kelly, Doug R. Burch, Ryan S. Mathews, Cameron W. Swanick, Sanford L. Meeks Source Type: research

Evaluation of thoracic surface motion during the free breathing and deep inspiration breath hold methods
The aim of this study was to evaluate thoracic surface motion from chest wall expansion during free breathing (FB) and deep inspiration breath hold (DIBH) methods, measured with and without 4-dimensional computed tomography (4D-CT) simulation, using equipment developed in-house. The respiratory amplitude and chest wall expansion were evaluated at 5 levels of the thorax, (the sterno-clavicular joint (SCJ), the second level, the intermammary line (IML), the fourth level and the caudal end of the xiphoid process (XP)) using radiopaque wires and potentiometers, with a CT scan simultaneously. (Source: Medical Dosimetry)
Source: Medical Dosimetry - March 22, 2021 Category: Radiology Authors: Milovan Savanovi ć, Bojan Štrbac, Bojan Mihajlović, Danijela Trokić, Dražan Jaroš, Goran Kolarević, Miloš Vićić, Jean-Noël Foulquier Source Type: research

Mean parotid dose prediction model using machine learning regression method for intensity-modulated radiotherapy in head and neck cancer
Parotids are considered one of the major organs at risk in Head and Neck (HN) intensity-modulated radiotherapy (IMRT). Achieving proper target coverage with reduced mean parotid dose demands an elaborate time-consuming IMRT plan optimization. A parotid mean dose prediction model based on a machine-learning linear regression was developed and validated in this study. The model was developed using independent variables, such as parotid to PTV overlapping volume, dose coverage of the overlapping PTV, the ratio of overlapping parotid volume to total parotid volume, and volume of parotid overlapping with isotopically expanded P...
Source: Medical Dosimetry - March 17, 2021 Category: Radiology Authors: CP Ranjith, Niyas puzhakkal, MP Arunkrishnan, R Vysakh, MP Irfad, KS Vijayagopal, S Jayashanker Source Type: research

The need for a dose constraint in hip prosthesis to minimize later hip dysfunction. A retrospective analysis of relevant cases
Results from a single-institution study support the need of a dose constraint for patients who have previously undergone hip replacement surgery. Our study provides evidence that a dose above 30 Gy to the area of hip prosthesis is significantly correlated with later hip arthroplasty dysfunction as measured by the Harris Hip Score. As total hip arthroplasty becomes more and more common, it is urgent to further look into radiation therapy treatment parameters that can be modified to improve the quality of life of patients who receive pelvic irradiation after hip arthroplasty. (Source: Medical Dosimetry)
Source: Medical Dosimetry - March 16, 2021 Category: Radiology Authors: Vassilis Kouloulias, Maria Protopapa, Anna Zygogianni, Georgios Patatoukas, Andromachi Kougioumtzopoulou, Olga Savvidou, Kalliopi Platoni Source Type: research

A predictive model for determining rectum and bladder dose constraints in prostate volumetric modulated arc therapy
Generic dose-volume constraints of the rectum/bladder (R/B) are used in inverse planning to reduce doses to these organs for patients undergoing prostate radiotherapy. A retrospective study was undertaken to assess correlations between the overlap of the R/B with the planning target volume (PTV) and the dose received during planning to organs at risk (OARs). Data for 105 prostate cancer patients who had volumetric modulated arc therapy (VMAT) to the intact prostate and proximal seminal vesicles at Nepean Cancer Care Centre from 2011 to 2015 were analyzed. (Source: Medical Dosimetry)
Source: Medical Dosimetry - March 13, 2021 Category: Radiology Authors: Menglei Chao, Natalie Coburn, Eireann Cosgriff, Chris Brown, Kevin Van Tilburg, Amy Hayden Source Type: research

Feasibility of a TPS-integrated method to incorporate tumor motion in the margin recipe
Background and purpose: There are several alternatives to the widespread ITV strategy in order to account for breathing-induced motion in PTV margins. The most sophisticated one includes the generation of a motion-compensated CT scan with the CTV placed in its average position – the mid-position approach (MidP). In such configuration, PTV margins integrate breathing as another random error. Despite overall irradiated volume reduction, such approach is barely used in clinical practice because of its dependence to deformable registration and its unavailability in commerci al treatment planning systems. (Source: Medical Dosimetry)
Source: Medical Dosimetry - March 5, 2021 Category: Radiology Authors: David Dechambre, Lo ïc Vander Veken, Antoine Delor, Edmond Sterpin, Françoise Vanneste, Xavier Geets Source Type: research

Case report of visual biofeedback-driven, magnetic resonance-guided single-fraction SABR in breath hold for early stage non –small-cell lung cancer
We present the case of a 66-year-old male with history of cholangiocarcinoma who was subsequently diagnosed with peripheral earl y stage NSCLC and treated in mid-inspiration breath hold (BH) to 34 Gy in 1 fraction on a magnetic resonance (MR)-guided linear accelerator, with treatment delivery completed in 17 minutes. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 26, 2021 Category: Radiology Authors: Michael D. Chuong, Rupesh Kotecha, Minesh P. Mehta, Sonia Adamson, Tino Romaguera, Matthew D. Hall, Diane Alvarez, Alonso N. Gutierrez, Vivek Mishra, Fernando De Zarraga, Kathryn E. Mittauer Source Type: research

Intensity-modulated proton therapy (IMPT) versus intensity-modulated radiation therapy (IMRT) for the treatment of head and neck cancer: A dosimetric comparison
It is the goal of this study to compare the dosimetric advantages of IMPT when compared to IMRT. From January 2019 to August 2020, 25 patients were treated with intensity modulated proton therapy (IMPT) at our institution for either recurrent, metastatic, benign, or primary tumors in the head and neck region. Twenty-one patients met criteria for dosimetric analysis. Histology of disease included squamous cell carcinoma, acinic cell carcinoma, sarcomatoid sinonasal carcinoma, paraganglioma, adenoid cystic carcinoma, salivary high grade carcinoma, and papillary thyroid carcinoma. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 26, 2021 Category: Radiology Authors: My-Lien Nguyen, J. Nathan Cantrell, Salahuddin Ahmad, Christina Henson Source Type: research

Management of multiple brain metastases via dual-isocenter VMAT stereotactic radiosurgery
Single-isocenter volumetric modulated arc therapy (VMAT) stereotactic radiosurgery (SRS) techniques to treat multiple brain metastases simultaneously can significantly improve treatment delivery efficiency, patient compliance, and clinic workflow. However, due to large number of brain metastases sharing the same MLC pair causing island blocking, there is higher low- and intermediate-dose spillage to the normal brain and higher dose to organs-at-risk (OAR). To minimize this problem and improve plan quality, this study proposes a dual-isocenter planning strategy that groups lesions based on hemisphere location (left vs right...
Source: Medical Dosimetry - February 3, 2021 Category: Radiology Authors: Allison N Palmiero, Denise Fabian, William St Clair, Marcus Randall, Damodar Pokhrel Source Type: research

Dosimetric assessment of brass mesh bolus and transparent polymer-gel type bolus for commonly used breast treatment delivery techniques
We investigated skin dose enhancements of brass mesh bolus (BMB) and a recently developed transparent polymer-gel bolus (PGB) for clinically relevant breast treatment delivery techniques. The dose enhancement of the breast surface with BMB and PGB were compared to that of tissue-equivalent bolus.Three breast treatment plans were generated on CT scans of an anthropomorphic chest phantom: tangential step-and-shoot 3D conformal (3DCRT) planned using Field-in-Field (FiF), tangential sliding-window 3DCRT using Electronic Compensator (EC), and volumetric modulated arc therapy (VMAT). (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 31, 2021 Category: Radiology Authors: Derek A. Fiedler, Sabrina Hoffman, John C. Roeske, Courtney L. Hentz, William Small, Hyejoo Kang Source Type: research