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https://www.readbyqxmd.com/read/29195567/review-of-technologies-and-procedures-of-clinical-dosimetry-for-scanned-ion-beam-radiotherapy
#1
REVIEW
S Giordanengo, L Manganaro, A Vignati
In the last few years, the use of ions in radiation therapy is gaining interest and it is being considered medically necessary for a growing subset of tumours. Concurrently, the technologies involved in a particle therapy treatment are rapidly evolving, as well as the accuracy in the dose delivery in spite of the increased complexity. Since nowadays, the pencil beam scanning technique is showing very interesting features in terms of dose conformation and overall treatment outcome, the present review is intended to summarize the main procedures, detectors and tools adopted for the clinical dose verification...
November 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/29173920/evaluation-and-clinical-implementation-of-in-vivo-dosimetry-for-kv-radiotherapy-using-radiochromic-film-and-micro-silica-bead-thermoluminescent-detectors
#2
Antony L Palmer, Shakardokht M Jafari, Ioanna Mone, Sarah Muscat
PURPOSE: kV radiotherapy treatment calculations are based on flat, homogenous, full-scatter reference conditions. However, clinical treatments often include surface irregularities and inhomogeneities, causing uncertainty. Therefore, confirmation of actual delivered doses in vivo is valuable. The current study evaluates, and implements, radiochromic film and micro silica bead TLD for in vivo kV dosimetry. METHODS: The kV energy and dose response of EBT3 film and silica bead TLD was established and uncertainty budgets determined...
October 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/29173910/epid-based-in-vivo-dosimetry-for-stereotactic-body-radiotherapy-of-non-small-cell-lung-tumors-initial-clinical-experience
#3
R Consorti, A Fidanzio, V Brainovich, F Mangiacotti, M De Spirito, M A Mirri, A Petrucci
PURPOSE: EPID-based in vivo dosimetry (IVD) has been implemented for stereotactic body radiotherapy treatments of non-small cell lung cancer to check both isocenter dose and the treatment reproducibility comparing EPID portal images. METHODS: 15 patients with lung tumors of small dimensions and treated with volumetric modulated arc therapy were enrolled for this initial experience. IVD tests supplied ratios R between in vivo reconstructed and planned isocenter doses...
October 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/29165319/comparison-of-forward-and-back-projection-in-vivo-epid-dosimetry-for-vmat-treatment-of-the-prostate
#4
James L Bedford, Ian Maddock Hanson, Vibeke N Hansen
In the forward-projection method of portal dosimetry for volumetric modulated arc therapy (VMAT), the integrated signal at the electronic portal imaging device (EPID) is predicted at the time of treatment planning, against which the measured integrated image is compared. In the back-projection method, the measured signal at each gantry angle is back-projected through the patient CT scan to give a measure of total dose to the patient. This study aims to investigate the practical agreement between the two types of EPID dosimetry for prostate radiotherapy...
November 22, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29164632/characterization-of-nanodot-optically-stimulated-luminescence-detectors-and-high-sensitivity-mcp-n-thermoluminescent-detectors-in-the-40-300-kvp-energy-range
#5
Yannick Poirier, Svetlana Kuznetsova, Jose Eduardo Villarreal-Barajas
PURPOSE: To investigate empirically the energy dependence of the detector response of two in-vivo luminescence detectors, LiF:Mg,Cu,P (MCP-N) high-sensitivity TLDs and Al2 O3 :C OSLDs, in the 40-300-kVp energy range in the context of in-vivo surface dose measurement. As these detectors become more prevalent in clinical and pre-clinical in-vivo measurements, knowledge of the variation of the empirical dependence of the measured response of these detectors across a wide spectrum of beam qualities is important...
November 22, 2017: Medical Physics
https://www.readbyqxmd.com/read/29152840/on-the-use-of-bolus-for-pacemaker-dose-measurement-and-reduction-in-radiation-therapy
#6
Huagang Yan, Fanqing Guo, Dengsong Zhu, Stefan Stryker, Sharron Trumpore, Kenneth Roberts, Susan Higgins, Ravinder Nath, Zhe Chen, Wu Liu
Special attention is required in planning and administering radiation therapy to patients with cardiac implantable electronic devices (CIEDs), such as pacemaker and defibrillator. The range of dose to CIEDs that can induce malfunction is large among CIEDs. Clinically significant defects have been reported at dose as low as 0.15 Gy. Therefore, accurate estimation of dose to CIED and dose reduction are both important even if the dose is expected to be less than the often-used 2-Gy limit. We investigated the use of bolus in in vivo dosimetry for CIEDs...
November 20, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29140458/direct-measurements-of-skin-eye-lens-and-thyroid-dose-during-pediatric-brain-ct-examinations
#7
Agapi Ploussi, Ioannis Stathopoulos, Vasileios Syrgiamiotis, Triantafillia Makri, Christiana Hatzigiorgi, Kalliopi Platoni, Eleftheria Carinou, Efstathios P Efstathopoulos
Pediatric brain computed tomography (CT) is identified as the most frequent CT examination in children. The aim of the study is the direct measurement of skin, eye lens and thyroid dose in pediatric patients during brain CT examinations. The study included 35 pediatric patients who underwent brain CT examinations. The patients were categorized in three age groups: Group A (age range: 0.8-1 years), Group B (age range: 2.0-4.9 years) and Group C (age range: 5.5-15.5 years). thermoluminescent dosimeters (TLDs) were placed on the eyes, the frontal region of the head, the mastoid apophysis and the thyroid gland...
November 13, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29136280/transitqa-a-new-method-for-transit-dosimetry-of-tomotherapy-patients
#8
Olivier Pisaturo, Frédéric Miéville, Pierre-Alain Tercier, Abdelkarim Said Allal
PURPOSE: TransitQA is an innovative method for Tomotherapy transit dosimetry using the on-board detector (OBD). Our previously published model for Tomotherapy treatment plan verification (AirQA) has been enhanced to take into account patient and couch transmission. AirQA estimates the OBD signal during irradiation with nothing in the beam path from the leaf control sinogram, allowing us to check whether the planned treatment is correctly delivered by the machine. TransitQA allows us to check the treatment delivery with the patient on the couch, potentially showing the effects of changes in the patient anatomy and delivery errors...
November 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/29129050/metal-free-cycloaddition-chemistry-driven-pretargeted-radioimmunotherapy-using-%C3%AE-particle-radiation
#9
Manan Shah, Xiuli Zhang, Raffaella Rossin, Marc S Robillard, Darrell Fisher, Tyler Bueltmann, Freek J M Hoeben, Thomas Quinn
The pretargeted radioimmunotherapy approach (PRIT) decouples the administration of tumor targeting monoclonal antibodies (mAb) from that of the radiolabeled ligand. This multi-step strategy allows delivery of high doses of radiation to tumor cells while minimizing non-specific normal tissue irradiation. In this study, we evaluated the potential of pretargeted α-particle radioimmunotherapy based on inverse electron demand Diels-Alder reaction (IEDAA) between trans-cyclooctene (TCO) and tetrazine (Tz). Two tetrazine based chelators, DOTA-Tz and TCMC-Tz, were synthesized and compared for their radiolabeling efficiency with 212Pb, radiochemical stability and in-vivo pharmacokinetics...
November 12, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/29125832/minibeam-radiotherapy-with-small-animal-irradiators-in-vitro-and-in-vivo-feasibility-studies
#10
Soha Bazyar, Christina R Inscoe, E Timothy O'Brian, Otto Zhou, Yueh Z Lee
Minibeam radiation therapy (MBRT) delivers an ultrahigh dose of x-ray (⩾100 Gy) in 200-1000 µm beams (peaks), separated by wider non-irradiated regions (valleys) usually as a single temporal fraction. Preclinical studies performed at synchrotron facilities revealed that MBRT is able to ablate tumors while maintaining normal tissue integrity. The main purpose of the present study was to develop an efficient and accessible method to perform MBRT using a conventional x-ray irradiator. We then tested this new method both in vitro and in vivo...
November 10, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29106380/pdt-dose-dosimetry-for-photofrin-mediated-pleural-photodynamic-therapy-ppdt
#11
Yi Hong Ong, Michele M Kim, Jarod C Finlay, Andreea Dimofte, Sunil Singhal, Eli Glatstein, Keith A Cengel, Timothy C Zhu
Photosensitizer fluorescence excited by photodynamic therapy (PDT) treatment light can be used to monitor the in-vivo concentration of the photosensitizer and its photobleaching. The temporal integral of the product of in-vivo photosensitizer concentration and light fluence is called PDT dose, which is an important dosimetry quantity for PDT. However, the detected photosensitizer fluorescence may be distorted by variations in the absorption and scattering of both excitation and fluorescence light in tissue...
November 6, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29102154/three-dimensional-printer-generated-patient-specific-phantom-for-artificial-in-vivo-dosimetry-in-radiotherapy-quality-assurance
#12
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
https://www.readbyqxmd.com/read/29082601/time-resolved-diode-dosimetry-calibration-through-monte-carlo-modeling-for-in%C3%A2-vivo-passive-scattered-proton-therapy-range-verification
#13
Allison Toltz, Michaela Hoesl, Jan Schuemann, Jan Seuntjens, Hsiao-Ming Lu, Harald Paganetti
PURPOSE: Our group previously introduced an in vivo proton range verification methodology in which a silicon diode array system is used to correlate the dose rate profile per range modulation wheel cycle of the detector signal to the water-equivalent path length (WEPL) for passively scattered proton beam delivery. The implementation of this system requires a set of calibration data to establish a beam-specific response to WEPL fit for the selected 'scout' beam (a 1 cm overshoot of the predicted detector depth with a dose of 4 cGy) in water-equivalent plastic...
October 29, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29077574/monte-carlo-simulation-of-radiation-transport-and-dose-deposition-from-locally-released-gold-nanoparticles-labeled-with-111-in-177-lu-or-90-y-incorporated-into-tissue-implantable-depots
#14
Priscilla Lai, Zhongli Cai, Jean-Philippe Pignol, Eli Lechtman, Shahram Mashouf, Yijie Lu, Mitchell A Winnik, David A Jaffray, Raymond M Reilly
Permanent seed implantation (PSI) brachytherapy is a highly conformal form of radiation therapy but is challenged with dose inhomogeneity due to its utilization of low energy radiation sources. Gold nanoparticles (AuNP) conjugated with electron emitting radionuclides have recently been developed as a novel form of brachytherapy and can aid in homogenizing dose through physical distribution of radiolabeled AuNP when injected intratumorally (IT) in suspension. However, the distribution is unpredictable and precise placement of many injections would be difficult...
October 27, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29077570/determination-of-mean-ionization-potential-using-magnetic-resonance-imaging-for-the-reduction-of-proton-beam-range-uncertainties-theory-and-application
#15
Atchar Sudhyadhom
The accurate determination of mean ionization potential (I m) has the potential to reduce range uncertainty based margins and therefore allow for more focal treatments in proton radiotherapy. Many methods have been proposed to reduce uncertainty in I m and stopping power ratios (SPR), each with varying degrees of accuracy and issues. In this work, we present a simple parameterized model to determine I m in human biological tissue, allowing for the computation of patient-specific I m at the voxel level using magnetic resonance imaging (MRI)...
October 27, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29057373/biokinetics-of-nanomaterials-the-role-of-biopersistence
#16
Peter Laux, Christian Riebeling, Andy M Booth, Joseph D Brain, Josephine Brunner, Cristina Cerrillo, Otto Creutzenberg, Irina Estrela-Lopis, Thomas Gebel, Gunnar Johanson, Harald Jungnickel, Heiko Kock, Jutta Tentschert, Ahmed Tlili, Andreas Schäffer, Adriënne J A M Sips, Robert A Yokel, Andreas Luch
Nanotechnology risk management strategies and environmental regulations continue to rely on hazard and exposure assessment protocols developed for bulk materials, including larger size particles, while commercial application of nanomaterials (NMs) increases. In order to support and corroborate risk assessment of NMs for workers, consumers, and the environment it is crucial to establish the impact of biopersistence of NMs at realistic doses. In the future, such data will allow a more refined future categorization of NMs...
April 2017: NanoImpact
https://www.readbyqxmd.com/read/29037107/first-in-man-evaluation-of-124-i-pgn650-a-pet-tracer-for-detecting-phosphatidylserine-as-a-biomarker-of-the-solid-tumor-microenvironment
#17
Richard Laforest, Farrokh Dehdashti, Yongjian Liu, Jennifer Frye, Sarah Frye, Hannah Luehmann, Deborah Sultan, Joseph S Shan, Bruce D Freimark, Barry A Siegel
PURPOSE: PGN650 is a F(ab')2 antibody fragment that targets phosphatidylserine (PS), a marker normally absent that becomes exposed on tumor cells and tumor vasculature in response to oxidative stress and increases in response to therapy. PGN650 was labeled with (124)I to create a positron emission tomography (PET) agent as an in vivo biomarker for tumor microenvironment and response to therapy. In this phase 0 study, we evaluated the pharmacokinetics, safety, radiation dosimetry, and tumor targeting of this tracer in a cohort of patients with cancer...
January 2017: Molecular Imaging
https://www.readbyqxmd.com/read/29025984/synthesis-and-biological-evaluation-of-a-novel-18-f-labeled-adnectin-as-a-pet-radioligand-for-imaging-pd-l1-expression
#18
David J Donnelly, Ralph Adam Smith, Paul Morin, Dasa Lipovsek, Jochem Gokemeijer, Daniel Cohen, Virginie Lafont, Tritin Tran, Erin Lee Cole, Martin Wright, Joonyoung Kim, Adrienne Pena, Daniel Kukral, Douglas D Dischino, Patrick Chow, Jinping Gan, Olufemi Adelakun, Xi-Tao Wang, Kai Cao, David Lueng, Samuel Bonacorsi, Wendy Hayes
The programmed death protein (PD-1) and its ligand (PD-L1) play critical roles in a checkpoint pathway cancer cells exploit to evade the immune system. A same-day PET imaging agent for measuring PD-L1 status in primary and metastatic lesions could be important for optimizing drug therapy. Herein, we have evaluated the tumor targeting of an anti-PD-L1 Adnectin after (18)F-fluorine labeling. Methods: An anti-PD-L1 Adnectin was labeled with (18)F in two steps. This synthesis featured fluorination of a novel prosthetic group, followed by a copper-free click conjugation to a modified Adnectin to generate (18)F-BMS-986192...
October 12, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/29017719/comparison-of-gamma-and-dvh-based-in-vivo-dosimetric-plan-evaluation-for-pelvic-vmat-treatments
#19
Erik van der Bijl, René F M van Oers, Igor Olaciregui-Ruiz, Anton Mans
BACKGROUND AND PURPOSE: To compare DVH-based quality assurance to a multi-parametric γ-based methodology for in vivo EPID dosimetry for VMAT to the pelvis. MATERIALS AND METHODS: For 47 rectum, 37 prostate, and 44 bladder VMAT treatments we reconstructed the 3D dose distributions of 387 fractions from in vivo EPID dosimetry. The difference between planned and measured dose was evaluated using γ analysis (3%/3mm) in the 50% isodose volume (IDV) and DVH differences (ΔD2, ΔD50 and ΔD98) of targets and organs at risk...
October 7, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28994669/minibeam-radiotherapy-with-small-animal-irradiators-i-in-vitro-i-and-i-in-vivo-i-feasibility-studies
#20
Soha Bazyar, Christina R Inscoe, E Timothy O'Brien Iii, Otto Z Zhou, Yueh Z Lee
Minibeam radiation therapy (MBRT) delivers ultrahigh dose of X-ray (≥100 Gy) in 200-1000 μm beams (peaks), separated by wider non-irradiated regions (valleys) usually as a single temporal fraction. Preclinical studies performed at synchrotron facilities revealed that MBRT is able to ablate tumors while maintaining normal tissue integrity. The main purpose of present study was to develop an efficient and accessible method to perform MBRT using a conventional X-ray irradiator. We then tested this new method both in-vitro and in-vivo...
October 10, 2017: Physics in Medicine and Biology
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