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Adaptive ultra-hypofractionated whole-pelvic radiotherapy in high-risk and very high-risk prostate cancer on 1.5-Tesla MR-Linac:Estimated delivered dose and early toxicity results

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Chronic Diseases and Translational Medicine 2024年第1期10卷 51-61页

作者： Linrui Gao Ran Wei Shirui Qin Yuan Tian Wenlong Xia Yongwen Song Shulian Wang Hui Fang Yu Tang Hao Jing Yueping Liu Yuan Tang Shunan Qi Bo Chen Yexiong Li Nianzeng Xing Ningning Lu Department of Radiation Oncology National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina GCP Center/Clinical Research Center National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Department of Urology State Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Background: Magnetic resonance(MR)-guided ultra-hypofractionated radiotherapy with whole-pelvic irradiation(UHF-WPRT)is a novel approach to radiotherapy for patients with high-risk(HR)and very high-risk(VHR)prostate cancer(PCa).However,the inherent complexity of adaptive UHF-WPRT might inevitably result in longer on-couch time.We aimed to estimate the delivered dose,study the feasibility and safety of adaptive UHF-WPRT on a 1.5-Tesla MR-Linac.Methods: Ten patients with clinical stage T3a-4N0-1M0-1c PCa,who consecutively received UHF-WPRT,were enrolled prospectively.The contours of the target and organ-at-risks on the position verification-MR(PV-MR),beam-on 3D-MR(Bn-MR),and post-MR(after radiotherapy delivery)were derived from the pre-MR data by deformable image registration.The physician then manually adjusted them,and dose recalculation was performed accordingly.GraphPad Prism 9(GraphPad Prism Software Inc.)was utilized for conducting statistical analyses.Results: In total,we collected 188 MR scans(50 pre-MR,50 PV-MR,44 Bn-MR,and 44 post-MR scans).With median 59 min,the mean prostate clinical target volume(CTV)-V_(100%)was 98.59%±2.74%,and the mean pelvic CTVp-V_(100%)relative percentages of all scans was 99.60%±1.18%.The median V29 Gy change in the rectal wall was−2%(−18%to 20%).With a median follow-up of 9 months,no patient had acute Common Terminology Criteria for Adverse Events(CTCAE)grade 2 or more severe genitourinary(GU)or gastrointestinal(GI)toxicities(0%).Conclusion: UHF-RT to the prostate and the whole pelvis with concomitant boost to positive nodes using an Adapt-To-Shape(ATS)workflow was technically feasible for patients with HR and VHR PCa,presenting only mild GU and GI toxicities.The estimated target dose during the beam-on phase was clinically acceptable based on the 3D-MR-based dosimetry analysis.Clinical trial registration Chinese Clinical Trial Registry ChiCTR2000033382.

关键词： dosimetry hypofractionation magnetic resonance imaging prostate cancer radiation dose radiotherapy

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A Study of the TPS Based Beam-Matching Concept for Medical Linear Accelerators at a Tertiary Hospital

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2024年第1期13卷 16-25页

作者： Ntombela N. Lethukuthula Rovetto J. Nicolas Nethwadzi C. Lutendo Mpumelelo Nyathi Department of Radiation Oncology Steve Biko Academic Hospital Pretoria South Africa Department of Medical Physics University of Pretoria Pretoria South Africa Department of Medical Physics Sefako Makgatho Health Sciences University Ga-Rankuwa South Africa

The flexibility in radiotherapy can be improved if patients can be moved between any one of the department’s medical linear accelerators (LINACs) without the need to change anything in the patient’s treatment plan. For this to be possible, the dosimetric characteristics of the various accelerators must be the same, or nearly the same. The purpose of this work is to describe further and compare measurements and parameters after the initial vendor-recommended beam matching of the five LINACs. Deviations related to dose calculations and to beam matched accelerators may compromise treatment accuracy. The safest and most practical way to ensure that all accelerators are within clinical acceptable accuracy is to include TPS calculations in the LINACs matching evaluation. Treatment planning system (TPS) was used to create three photons plans with different field sizes 3 × 3 cm, 10 × 10 cm and 25 × 25 cm at a depth of 4.5 cm in Perspex. Calculated TPS plans were sent to Mosaiq to be delivered by five LINACs. TPS plans were compared with five LINACs measurements data using Gamma analyses of 2% and 2 mm. The results suggest that for four out of the five LINACs, there was generally good agreement, less than a 2% deviation between the planned dose distribution and the measured dose distribution. However, one specific LINAC named “Asterix” exhibited a deviation of 2.121% from the planned dose. The results show that all of the LINACs’ performance were within the acceptable deviation and delivering radiation dose consistently and accurately.

关键词： Radiotherapy Beam-Matching Linear Accelerator dosimetry

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Comparison of dosimetry with magnetic resonance and computed tomography imaging delineation of surgical bed volume in breast cancer irradiation

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Cancer Pathogenesis and Therapy 2023年第1期1卷 12-17页

作者： M.Betti L.C.Orlandini C.Biagini M.De Liguoro L.Cionini Medical Physics Department Centro Oncologico Fiorentino50019Sesto Fiorentino(FI)Italy Medical Physics Department PistoiaAzienda USL Toscana Centro51100Pistoia(PT)Italy Radiation Oncology Department Sichuan Cancer Hospital&Research InstituteChengduSichuan 610041China Diagnostic Department Diagnostic Institute Santo Stefano59100Prato(PO)Italy Radiation Oncology Department Azienda sanitaria Locale Asti14100Asti(AT)Italy Radiation Oncology Department Centro Oncologico Fiorentino50019Sesto Fiorentino(FI)Italy

Background Postoperative radiotherapy after conservative surgery for patients with breast cancer usually includes focal over-irradiation(boost)to the surgical bed(SB).Irradiation planning using computed tomography(CT)is difficult in many cases because of insufficient intrinsic soft tissue contrast.To ensure appropriate radiation to the tumor,large boost volumes are delineated,resulting in a higher dose to the normal tissue.Magnetic resonance imaging(MRI)provides superior soft tissue contrast than CT and can better differentiate between normal tissue and the SB.However,for SB delineation CT images alone remain the pathway followed in patients undergoing breast irradiation.This study aimed to evaluate the potential advantages in boost dosimetry by using MRI and CT as pre-treatment imaging.Methods Eighteen boost volumes were drawn on CT and MRI and elastically co-registered using commercial image registration software.The radiotherapy treatment plan was optimized using the CT volumes as the baseline.The dose distributions of the target volumes on CT and MRI were compared using dose-volume histogram cutoff points.Results The radiation volumes to the SB varied considerably between CT and MRI(conformity index between 0.24 and 0.67).The differences between the MRI and CT boost doses in terms of the volume receiving 98%of the prescribed dose(V98%)varied between 10%and 30%.Smaller differences in the V98%were observed when the boost volumes were delineated using MRI.Conclusion Using MRI to delineate the volume of the SB may increase the accuracy of boost dosimetry.

关键词： Breast radiotherapy MRI Boost delineation Seroma dosimetry

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dosimetry Comparison between Volumetric Modulated Arc Therapy with RapidArc and Fixed Field Dynamic IMRT for Local-Regionally Advanced Nasopharyngeal Carcinoma

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Chinese Journal of Cancer Research 2011年第4期23卷 259-264页

作者： Bao-min Zheng Xiao-xia Dong Hao Wu You-jia Duan Shu-kui Han Yan Sun Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education) Department of RadiotherapyPeking University School of Oncology Beijing Cancer Hospital & Institute Beijing 100142 China

Objective: A dosimetric study was performed to evaluate the performance of volumetric modulated arc radiotherapy with RapidArc on locally advanced nasopharyngeal carcinoma (NPC). Methods: The CT scan data sets of 20 patients of locally advanced NPC were selected randomly. The plans were managed using volumetric modulated arc with RapidArc and fixed nine-field coplanar dynamic intensity-modulated radiotherapy (IMRT) for these patients. The dosimetry of the planning target volumes (PTV), the organs at risk (OARs) and the healthy tissue were evaluated. The dose prescription was set to 70 Gy to the primary tumor and 60 Gy to the clinical target volumes (CTV) in 33 fractions. Each fraction applied daily, five fractions per week. The monitor unit (MU) values and the delivery time were scored to evaluate the expected treatment efficiency. Results: Both techniques had reached clinical treatment’s requirement. The mean dose (Dmean), maximum dose (Dmax) and minimum dose (Dmin) in RapidArc and fixed field IMRT for PTV were 68.4±0.6 Gy, 74.8±0.9 Gy and 56.8±1.1 Gy; and 67.6±0.6 Gy, 73.8±0.4 Gy and 57.5±0.6 Gy (P0.05). Compared to IMRT, RapidArc allowed a reduction of Dmean to the brain stem, mandible and optic nerves of 14.1% (P<0.05), 5.6% (P<0.05) and 12.2% (P<0.05), respectively. For the healthy tissue and the whole absorbed dose, Dmean of RapidArc was reduced by 3.6% (P<0.05), and 3.7% (P<0.05), respectively. The Dmean to the parotids, the spinal cord and the lens had no statistical difference among them. The mean MU values of RapidArc and IMRT were 550 and 1,379. The mean treatment time of RapidArc and IMRT was 165 s and 447 s. Compared to IMRT, the delivery time and the MU values of RapidArc were reduced by 63% and 60%, respectively. Conclusion: For locally advanced NPC, both RapidArc and IMRT reached the clinic requirement. The target volume coverage wa

关键词： Volumetric modulated arc therapy Intensity-modulated radiotherapy dosimetry Target volume Nasopharyngeal carcinoma

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Synthesis and luminescence in LiMgPO_4:Tb,Sm,B phosphors with possible applications in real-time dosimetry

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Journal of Rare Earths 2013年第6期31卷 551-554页

作者：盖敏强陈朝阳范艳伟王军华 Xinjiang Technical Institute of Physics & Chemistry Chinese Academy of Sciences Xinjiang Key Laboratory of Electronic Information Materials and Devices University of Chinese Academy of Sciences

The objective of this work was to develop possible materials for optically stimulated luminescence （OSL） dosimetric applications in real-time measurement. A novel material of LiMgPO4：Tb,Sm,B was prepared by solid-state diffusion method at 900 oC. The structure and optical properties of these phosphors were characterized by X-ray diffraction, fluorescence spectro？photometer, and OSL reader. The results showed that the full discrimination between the stimulation and emission spectra made them very fit for the optic-fibre dosimetry. The OSL vs. dose response was linear in the dose range of 0.1 to 216 Gy. It also showed a significant improvement in the stimulation time compared with LiMgPO4：Tb,B. Hence, the phosphor could be used in the real-time dosimeter based on the OSL technology for medical monitoring as well as for environmental dosimetry and space dosimetry.

关键词： dosimetry LiMgPO4：Tb,B optic-fibre OSL real-time rare earths

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Modelling the interaction of the Astro Bio Cube Sat with the Van Allen's Belt radiative field using Monte Carlo transport codes

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Radiation Detection Technology and Methods 2022年第2期6卷 262-279页

作者： N.Burgio L.Cretara M.Corcione M.Frullini L.lannascoli A.Nascetti A.Santagata G.Palmerini A.Quintino J.R.Brucato A.Meneghin D.Paglialunga ENEA FSN-FISS-RNRC.R.CasacciaRomeItaly DIAEE Sapienza UniversitàDi RomaVia Eudossiana 1800184 RomeItaly School of Aerospace Engineering Sapienza University of RomeVia Salaria 85100138 RomeItaly INAF-Astrophysical Observatory of Arcetri L.go E.Fermi 550125 FlorenceItaly

Purpose The AstroBio Cube Satellite(ABCS)will deploy within the inner Van Allen belt on the Vega C Maiden Flight launch opportunity of the European Space Agency.At this altitude,ABCS will experience radiation doses orders of magnitude greater than in low earth orbit,where CubeSats usually operate.The paper aims to estimate the irradiation effect on the ABCS payload in the orbital condition,their possible mitigation designing shielding solutions and performs a preliminary representativity simulation study on the ABCS irradiation with fission neutron at the TAPIRO(TAratura Pila Rapida Potenza 0)nuclear research reactor facility at ENEA.Methods We quantify the contributions of geomagnetically trapped particles(electron and proton),Galactic Cosmic Rays(GCR ions),Solar energetic particle within the ABCS orbit using the ESA's SPace ENVironment information system.FLUKA(Fluktuierende Kaskade-Fluctuating Cascade)code models the ABCS interaction with the orbital source.Results We found a shielding solution of the weight of 300 g constituted by subsequent layers of tungsten,resins,and aluminium that decreases on average the 20%overall dose rate relative to the shielding offered by the only satellite's structure.Finally,simulations of neutron irradiation of the whole ABCS structure within the TAPIRO's thermal column cavity show that a relatively short irradiation time is requested to reach the same level of 1 MeV neutron Silicon equivalent damage of the orbital source.Conclusions The finding deserves the planning of a future experimental approach to confirm the TAPIRO's performance and establish an irradiation protocol for testing aerospatial electronic components.

关键词： Galactic cosmic rays and solar energetic particles Spacecraft shielding dosimetry Monte Carlo methods MCNP and FLUKA

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Variation in patient dose due to differences in calibration and dosimetry protocols

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Nuclear Science and Techniques 2018年第5期29卷 44-49页

作者： Wazir Muhammad Asad Ullah Gulzar Khan Tahir Zeb Khan Tauseef Jamaal Fawad Ullah Matiullah Khan Amjad Hussain Department of Therapeutic Radiology Yale-School of MedicineYale UniversityNew HavenCT 06520-8040USA Heath Physics Division(HPD) Pakistan Institute of Nuclear Science and Technology(PINSTECH)Islamabad 45650Pakistan Department of Physics Abul Wali Khan UniversityMardan 23200Pakistan Pakistan Institute Nuclear Science&Technology(PIEAS) Islamabad 45650Pakistan Department of Physics Kohat University of Science and TechnologyKohat 26000Pakistan Department of Medical Physics CancerCare ManitobaBrandonMB R7A 2B3Canada

For precise and accurate patient dose delivery,the dosimetry system must be calibrated properly according to the recommendations of standard dosimetry protocols such as TG-51 and TRS-398. However, the dosimetry protocol followed by a calibration laboratory is usually different from the protocols that are followed by different clinics, which may result in variations in the patient dose.Our prime objective in this study was to investigate the effect of the two protocols on dosimetry measurements.Dose measurements were performed for a Co-60 teletherapy unit and a high-energy Varian linear accelerator with 6 and 15 MV photon and 6, 9, 12, and 15 MeV electron beams, following the recommendations and procedures of the AAPM TG-51 and IAEA TRS-398 dosimetry protocols. The dosimetry systems used for this study were calibrated in a Co-60 radiation beam at the Secondary Standard dosimetry Laboratory(SSDL) PINSTECH,Pakistan, following the IAEA TRS-398 protocol. The ratio of the measured absorbed doses to water in clinical setting,D_w(TG-51/TRS-398), was 0.999 and 0.997 for 6 and15 MV photon beams,whereas these ratios were 1.013,1.009, 1.003, and 1.000 for 6, 9, 12, and 15 MeV electron beams, respectively. This difference in the absorbed dosesto-water D_w ratio may be attributed mainly due to beam quality(K_Q) and ion recombination correction factor.

关键词： Radiation dosimetry dosimetry systems calibrations Patient dose Absorbed dose-to-water ratio AAPM TG-51 IAEA TRS-398

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High Energy X-Ray dosimetry Using(ZnO)_(0.2)(TeO_(2))_(0.8)Thin Film-based Real-time X-Ray Sensor

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Non-Metallic Material Science 2023年第1期5卷 4-13页

作者： M.M.Idris I.O.Olarinoye M.T.Kolo S.O.Ibrahim J.K.Audu Department of Physics Federal University of TechnologyP.M.B 65MinnaNigeria Department of Physics Nasarawa State UniversityP.M.B 1022KeffiNigeria Department of Physics University Putra43400Malaysia Department of Medical Physics and Radiotherapy National HospitalP.M.B 425AbujaNigeria

This study reports the dosimetric response of a(ZnO)_(0.2)(TeO_(2))_(0.8)thin film sensor irradiated with high-energy X-ray radiation at various doses.The spray pyrolysis method was used for the film deposition on soda-lime glass substrate using zinc acetate dehydrate and tellurium dioxide powder as the starting precursors.The structural and morphological properties of the film were determined.The I-V characteristics measurements were performed during irradiation with a 6 MV X-ray beam from a Linac.The results revealed that the XRD pattern of the AS-deposited thin film is non-crystalline(amorphous)in nature.The FESEM image shows the non-uniform shape of nanoparticles agglomerated separately,and the EDX spectrum shows the presence of Te,Zn,and O in the film.The I-V characteristics measurements indicate that the current density increases linearly with X-ray doses(0-250 cGy)for all applied voltages(1-6 V).The sensitivity of the thin film sensor has been found to be in the range of 0.37-0.94 mA/cm^(2)/Gy.The current-voltage measurement test for fading normalised in percentage to day 0 was found in the order of day 0>day 15>day 30>day 1>day 2.These results are expected to be beneficial for fabricating cheap and practical X-ray sensors.

关键词： Thin film X-ray radiation I-V characteristics dosimetry

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Advances in Y-90 radioembolization for the treatment of hepatocellular carcinoma

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Hepatoma Research 2022年第1期8卷 9-21页

作者： Andrew J.Woerner Guy E.Johnson Department of Radiology Section of Interventional RadiologyUniversity of WashingtonSeattleWA 98195USA

Hepatocellular carcinoma remains a prominent cause of cancer-related mortality globally.Transarterial yttrium-90 radioembolization is a versatile therapy and plays an important role in the treatment of hepatocellular carcinoma.This review summarizes the establishment of radioembolization in the hepatocellular carcinoma treatment paradigm,treatment considerations across cancer stages,and recent advances in evidence.

关键词： Hepatocellular carcinoma radioembolization yttrium-90 dosimetry radiation segmentectomy

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Surface potential uniformity and sensitivity of large-area PTFE electret discs of different thicknesses produced by a modified corona poling rotating system for dosimetry applications

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Journal of Advanced Dielectrics 2019年第6期9卷 52-62页

作者： A.Komeijani H.Bagheri B.Shekarchi AJA Radiation Sciences Research Center(ARSRC)Science and Research Branch AJA University of Medical Sciences Tehran Iran

In this study,large-area(6-cm diameter)Teflon polytetrafluoroethylene(PTFE)discs of different thicknesses(0.2-,0.5-and 1-mm)were negatively and positively charged by using the“modified single point-to-plane corona poling rotating system”.The effects of some crucial parameters of the PTFE disc as well as the modified corona poling rotating system on the PTFE surface potential uniformity such as.(a)PTFE disc thickness,(b)PTFE disc polarity and(c)needle-to-PTFE disc distance were successfully reported.Accordingly,closer needle-to-PTFE disc distance,positive charging mode and thinner PTFE disc provided a better PTFE surface potential uniformity.However,the effects of PTFE charge polarity and needle distance on the electrostatic charge potential uniformity were much more remarkable in comparison with the effects of PTFE thickness.Additionally,the surface potential distribution profiles of charged PTFE discs were totally flat and independent of the PTFE thickness at 5-and 13-mm needle distances for the negative and positive charging modes,respectively.At the optimized charging conditions,large-area PTFE electret disc(0.5-mm-thick)with positive uniform surface charge potential especially at the edges up to1.8 kV with stability up to 77 days studied was produced by applying a new multiple heat treatment protocol to the PTFE disc for radon dosimetry.As also observed in this study,the sensitivity of PTFE electret dosimeters to a defined radon gas concentration increases as the PTFE thickness increases.Meanwhile,0.5-mm-thick PTFE electret disc produced was selected to be used as a high quality electret dosimeter with acceptable and superior parameters for different applications in particular medium-term radiation dosimetry in both low and high dose rate ionizing radiation fields.

关键词： PTFE electrets dielectric polarization surface charge uniformity and stability electrostatic discharges and measurements dosimetry

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