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Physica Medica: PM

Marco Brambilla
No abstract text is available yet for this article.
January 10, 2018: Physica Medica: PM
Marianne Camille Aznar, Samantha Warren, Mischa Hoogeman, Mirjana Josipovic
Stereotactic body radiotherapy (SBRT) for lung tumours has been gaining wide acceptance in lung cancer. Here, we review the technological evolution of SBRT delivery in lung cancer, from the first treatments using the stereotactic body frame in the 1990's to modern developments in image guidance and motion management. Finally, we discuss the impact of current technological approaches on the requirements for quality assurance as well as future technological developments.
January 10, 2018: Physica Medica: PM
Hamid Abdollahi, Shayan Mostafaei, Susan Cheraghi, Isaac Shiri, Seied Rabi Mahdavi, Anoshirvan Kazemnejad
OBJECTIVES: Immediately or after head-and-neck (H&N) cancer chemoradiotherapy (CRT), patients may undergone significant sensorineural hearing loss (SNHL) which could affect their quality of life. Radiomic feature analysis is proposed to predict SNHL induced by CRT. MATERIAL AND METHODS: 490 image features of 94 cochlea from 47 patients treated with three dimensional conformal RT (3DCRT) for different H&N cancers were extracted from CT images. Different machine learning (ML) algorithms and also least absolute shrinkage and selection operator (LASSO) penalized logistic regression were implemented on radiomic features for feature selection, classification and prediction...
January 9, 2018: Physica Medica: PM
Pietro Mancosu, Andrew Nisbet, Núria Jornet
Stereotactic body radiation therapy (SBRT) has become a standard treatment for non-operable patients with early stage non-small cell lung cancer (NSCLC). In this context, medical physics community has largely helped in the starting and the growth of this technique. In fact, SBRT requires the convergence of many different features for delivering large doses in few fractions to small moving target in an heterogeneous medium. The special issue of last month, was focused on the different physics challenges in lung SBRT...
January 9, 2018: Physica Medica: PM
Virginia Tsapaki, Geoff Ibbott, Anchali Krisanachinda, Kwan-Hoong Ng, Tae-Suk Suh, Slavik Tabakov, John Damilakis
As medical technology evolves and patient needs increase, the need for well-trained and highly professional medical physicists (MPs) becomes even more urgent. The roles and responsibilities of MPs in various departments within the hospital are diverse and demanding. It is obvious that training, continuing education and professional development of MPs have become essential. One of the ways for an MP to advance his or her knowledge is to participate in conferences and congresses. Last year, the 22nd International Conference of Medical Physics (ICMP 2016) took place in Bangkok, Thailand...
December 6, 2017: Physica Medica: PM
A Bruschi, M Esposito, S Pini, A Ghirelli, G Zatelli, S Russo
PURPOSE: Aim of this work was to study how the detector resolution can affect the clinical significance of SBRT pre-treatment volumetric modulated arc therapy (VMAT) verification results. METHODS: Three detectors (PTW OCTAVIUS 4D 729, 1500 and 100 SRS) used in five configurations with different resolution were compared: 729, 729 merged, 1500, 1500 merged and 1000 SRS. Absolute local gamma passing rates of 3D pre-treatment quality assurance (QA) were evaluated for 150 dose distributions in 30 plans...
December 1, 2017: Physica Medica: PM
Iuliana Toma-Dasu, Andrzej Wojcik, Emely Kjellsson Lindblom
No abstract text is available yet for this article.
November 9, 2017: Physica Medica: PM
Daisuke Shimao, Naoki Sunaguchi, Tenta Sasaya, Tetsuya Yuasa, Shu Ichihara, Tomonori Kawasaki, Masami Ando
PURPOSE: In this study, we demonstrate a novel imaging technique, based on ultra-small-angle X-ray scattering (USAXS) that uses a Laue-case Si wafer as the angle analyzer. METHODS: We utilized the (1 1 1) diffraction plane of a 356 μm thick, symmetrically cut Si wafer as the angle analyzer, denoted by A[L]. With this device, we performed USAXS imaging experiments using 19.8 keV synchrotron X-rays. The objects we imaged were formalin-fixed, paraffin-embedded breast tumors (an invasive carcinoma and an intraductal papilloma)...
November 4, 2017: Physica Medica: PM
Kosuke Matsubara, Hiroji Nagata, Rena Okubo, Tadanori Takata, Masanao Kobayashi
PURPOSE: We have proposed a method for determining the half-value layers (HVL) in dual-source dual-energy computed tomography (DS-DECT) scans without the need for the X-ray tubes to be fixed. METHODS: A custom-made lead-covered case and an ionizing chamber connected with a multi-function digitizer module (a real-time dosimeter) were used. The chamber was placed in the center of the case, and aluminum or copper filters were placed in front of the aperture. The HVL was measured using aperture widths of 1...
October 27, 2017: Physica Medica: PM
Takeshi Kamomae, Hidetoshi Shimizu, Takayoshi Nakaya, Kuniyasu Okudaira, Takahiro Aoyama, Hiroshi Oguchi, Masataka Komori, Mariko Kawamura, Kazuhiro Ohtakara, Hajime Monzen, Yoshiyuki Itoh, Shinji Naganawa
Pretreatment intensity-modulated radiotherapy quality assurance is performed using simple rectangular or cylindrical phantoms; thus, the dosimetric errors caused by complex patient-specific anatomy are absent in the evaluation objects. In this study, we construct a system for generating patient-specific three-dimensional (3D)-printed phantoms for radiotherapy dosimetry. An anthropomorphic head phantom containing the bone and hollow of the paranasal sinus is scanned by computed tomography (CT). Based on surface rendering data, a patient-specific phantom is formed using a fused-deposition-modeling-based 3D printer, with a polylactic acid filament as the printing material...
October 25, 2017: Physica Medica: PM
Annabelle M Austin, Michael J J Douglass, Giang T Nguyen, Scott N Penfold
PURPOSE: Proton therapy can be a highly effective strategy for the treatment of tumours. However, compared with X-ray therapy it is more expensive and has limited availability. In addition, it is not always clear whether it will benefit an individual patient more than a course of traditional X-ray therapy. Basing a treatment decision on outcomes of clinical trials can be difficult due to a shortage of data. Predictive modelling studies are becoming an attractive alternative to supplement clinical decisions...
December 2017: Physica Medica: PM
T Veselsky, J Novotny, V Pastykova, I Koniarova
PURPOSE: The aim of this study was to determine small field correction factors for a synthetic single-crystal diamond detector (PTW microDiamond) for routine use in clinical dosimetric measurements. MATERIALS AND METHODS: Correction factors following small field Alfonso formalism were calculated by comparison of PTW microDiamond measured ratio MQclinfclin/MQmsrfmsr with Monte Carlo (MC) based field output factors ΩQclin,Qmsrfclin,fmsr determined using Dosimetry Diode E or with MC simulation itself...
December 2017: Physica Medica: PM
Mauro Carrara, Davide Cusumano, Tommaso Giandini, Chiara Tenconi, Ester Mazzarella, Simone Grisotto, Eleonora Massari, Davide Mazzeo, Annamaria Cerrotta, Brigida Pappalardi, Carlo Fallai, Emanuele Pignoli
PURPOSE: A direct planning approach with multi-channel vaginal cylinders (MVCs) used for HDR brachytherapy of vaginal cancers is particularly challenging. Purpose of this study was to compare the dosimetric performances of different forward and inverse methods used for the optimization of MVC-based vaginal treatments for endometrial cancer, with a particular attention to the definition of strategies useful to limit the high doses to the vaginal mucosa. METHODS: Twelve postoperative vaginal HDR brachytherapy treatments performed with MVCs were considered...
December 2017: Physica Medica: PM
Andrea Jane Doyle, Deirdre M King, Jacinta E Browne
Ultrasound guided brachytherapy for the treatment of prostate cancer has become a routine treatment option, due to many benefits including patient recovery and dose localisation [1]; however it is not clear whether the standards which govern the image quality for these systems are adequate. Upon review of the recommended standards for ultrasound systems used in prostate brachytherapy procedures, the recommended tests do not appear to be specific to the clinical application of ultrasound guided prostate brachytherapy...
December 2017: Physica Medica: PM
Assi Valve, Jani Keyriläinen, Jarmo Kulmala
PURPOSE: To use Compass as a model-based quality assurance (QA) tool for stereotactic body radiation therapy (SBRT) and stereotactic radiation therapy (SRT) volumetric modulated arc therapy (VMAT) treatment plans calculated with Eclipse treatment planning system (TPS). MATERIALS AND METHODS: Twenty clinical stereotactic VMAT SBRT and SRT treatment plans were blindly selected for evaluation. Those plans included four different treatment sites: prostate, brain, lung and body...
December 2017: Physica Medica: PM
Peter Manser, Silvia Peter, Werner Volken, Martin A Zulliger, Andres Laib, Bruno Koller, Michael K Fix
Micro computed tomography (µCT) scanners are used to create high-resolution images and to quantify properties of the scanned objects. While modern µCT scanners benefit from the cone beam geometry, they are compromised by scatter radiation. This work aims to develop a Monte Carlo (MC) model of a µCT scanner in order to characterize the scatter radiation in the detector plane. The EGS++ framework with the MC code EGSnrc was used to simulate the particle transport through the main components of the XtremeCT (SCANCO Medical AG, Switzerland)...
December 2017: Physica Medica: PM
Anna Petoukhova, Iris Rüssel, Julienne Nijst-Brouwers, Ko van Wingerden, Jaap van Egmond, Daphne Jacobs, Andreas Marinelli, Joost van der Sijp, Peter Koper, Henk Struikmans
PURPOSE: The purpose of this study was to compare the delivered dose to the expected intraoperative radiation therapy (IORT) dose with in vivo dosimetry. For IORT using electrons in accelerated partial breast irradiation, this is especially relevant since a high dose is delivered in a single fraction. METHODS: For 47 of breast cancer patients, in vivo dosimetry was performed with MOSFETs and/or GAFCHROMIC EBT2 films. A total dose of 23.33 Gy at dmax was given directly after completing the lumpectomy procedure with electron beams generated with an IORT dedicated mobile accelerator...
December 2017: Physica Medica: PM
E Mastella, S Molinelli, G Magro, A Mirandola, S Russo, A Vai, A Mairani, K Choi, M R Fiore, P Fossati, F Cuzzocrea, A Gasbarrini, F Benazzo, S Boriani, F Valvo, R Orecchia, M Ciocca
PURPOSE: The aim of this study was to evaluate the dosimetric impact caused by recently introduced carbon fiber reinforced polyetheretherketone (CF/PEEK) stabilization devices, in comparison with conventional titanium (Ti) implants, for post-operative particle therapy (PT). METHODS: As a first step, protons and carbon ions Spread-Out Bragg Peaks (SOBPs) were delivered to CF/PEEK and Ti screws. Transversal dose profiles were acquired with EBT3 films to evaluate beam perturbation...
December 2017: Physica Medica: PM
Eeva Boman, Maija Rossi, Mika Kapanen
PURPOSE: To investigate the use of dual isocenters for VMAT planning in patients with lymph node positive synchronous bilateral breast cancer (BBC) compared to a single isocenter option. METHODS: Treatment plans of 11 patients with lymph node positive BBC were retrospectively analyzed using two different VMAT planning techniques: dual-isocenter split-arc VMAT plans (Iso2) were compared with mono-isocenter VMAT plans (Iso1). For Iso2 plans, PTV dose was investigated after introducing ±2 and ±5 mm couch shift errors between the two isocenters in the lateral, longitudinal and vertical direction...
December 2017: Physica Medica: PM
Evelina Jaselskė, Diana Adlienė, Viktoras Rudžianskas, Benas Gabrielis Urbonavičius, Arturas Inčiūra
In vivo dosimetry is a powerful tool for dose verification in radiotherapy. Its application in high dose rate (HDR) brachytherapy is usually limited to the estimation of gross errors, due to inability of the dosimetry system/ method to record non-uniform dose distribution in steep dose gradient fields close to the radioactive source. In vivo dose verification in interstitial catheter based HDR brachytherapy is crucial since the treatment is performed inserting radioactive source at the certain positions within the catheters that are pre-implanted into the tumour...
December 2017: Physica Medica: PM
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