- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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MSOT/CT/MR imaging Guided and hypoxia Maneuvered Oxygen self-sufficiency radiotherapy based on One-pot MnO2-mSiO2 @ Au nanoparticle
摘要： Radiotherapy (RT) is one of the most widely applied treatments for cancer therapy in the clinic. Herein, we constructed an innovative multifunctional nanotheranostic MnO2-mSiO2@Au-HA nanoparticles (MAHNPs) based on one-pot MnO2-mSiO2 nanohybrids (MNHs) and gold nanoparticles (AuNPs) for multispectral optoacoustic tomography (MSOT)/ computed tomography (CT) and magnetic resonance (MR) imaging guided hypoxia-maneuvered radiotherapy. The MNHs were prepared by a facile one-pot approach which avoided the leakage of MnO2 nanoparticles as well as increased the efficiency on preparation. The Mn2+ ions could trigger the breakdown of endogenous H2O2 to generate O2 to convert the hypoxic tumor micro-environment (TME), thus enhancing radiotherapy by self-sufficiency oxygen. In addition, hyaluronic acid (HA) was employed to modify the surface of MnO2-mSiO2@Au nanoparticles to improve biocompatibility and cellular uptake. The well-designed nanoparticles could perform remarkable photothermal therapy (PTT) and hypoxia-maneuvered radiotherapy (RT) simultaneously as well as MSOT/CT/MR imaging. In vivo studies showed that MAHNPs achieved almost entirely suppression of tumor growth without observable recurrence, which raised new possibilities for clinical nanotheranostics with multimodal diagnostic and therapeutic coalescent design.
关键词： photothermal therapy (PTT),gold nanoparticles,nanotheranostics,MSOT/CT/MR imaging,hypoxia-maneuvered radiotherapy,MnO2-mSiO2 nanohybrids
更新于2025-11-19 16:56:35
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Development and commissioning of a full-size prototype fixed-beam radiotherapy system with horizontal patient rotation
摘要： Purpose: Compared to conventional linacs with rotating gantries, a fixed-beam radiotherapy system could be smaller, more robust and more cost effective. In this work, we developed and commissioned a prototype x-ray radiotherapy system utilizing a fixed vertical radiation beam and horizontal patient rotation. Methods: The prototype system consists of an Elekta Synergy linac with gantry fixed at 0° and a custom-built patient rotation system (PRS). The PRS was designed to immobilize patients and safely rotate them about the horizontal axis. The interlocks and emergency stops of the linac and PRS were connected. Custom software was developed to monitor the system status, control the motion of the PRS and modify treatment plans for the fixed beam configuration. Following installation, the prototype system was commissioned for 3D conformal therapy based on guidelines specified in AAPM TG-45 and TG-142, with modifications for the fixed-beam geometry made where necessary. Results: The system and control software were tested in a variety of machine states and executed motion, stop and beam gating commands as expected. Interlocks and emergency stops of the linac and PRS were found to correctly stop PRS motion and both kV and MV radiation beams when triggered. For 3D conformal treatments, the prototype system met all AAPM TG-45 and TG-142 specifications for geometric and dosimetric accuracy. Motion of the PRS was within 0.6 ± 0.3 mm and 0.10° ± 0.07° of input values for translation and rotation respectively. The axis of rotation of the PRS was coincident with the radiation beam axis to less than 1 mm. End-to-end treatment verification for 6 MV conformal treatments showed less than 2% difference between planned and delivered dose for all fields. Conclusion: In this work, we have developed and commissioned a radiotherapy system that utilizes a fixed vertical radiation beam and horizontal patient rotation. This system is a proof-of-concept prototype for a fixed-beam treatment system without a rotating gantry. Fixed-beam systems that are smaller and more cost-effective could help in improving global access to radiotherapy.
关键词： Fixed-beam radiotherapy,patient rotation
更新于2025-09-23 15:23:52
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ICRU report?91 on prescribing, recording, and reporting of stereotactic treatments with small photon beams; ICRU-Bericht 91 über die Verschreibung, Aufzeichnung und Dokumentation von stereotaktischen Behandlungen mit kleinen Photonenfeldern;
摘要： The International Commission on Radiation Units and Measurements (ICRU) report 91 with the title “prescribing, recording, and reporting of stereotactic treatments with small photon beams” was published in 2017. This extensive publication covers different relevant aspects of stereotactic radiotherapy such as small field dosimetry, accuracy requirements for volume definition and planning algorithms, and the precise application of treatment by means of image guidance. Finally, recommendations for prescribing, recording and reporting are given.
关键词： Organs at risk,Stereotactic radiotherapy,Radiotherapy planning, computer-assisted,Stereotactic body radiation therapy,Stereotactic radiosurgery
更新于2025-09-23 15:22:29
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Development and clinical evaluation of a simple optical method to detect and measure patient external motion
摘要： A simple and independent system to detect and measure the position of a number of points in space was devised and implemented. Its application aimed to detect patient motion during radiotherapy treatments, alert of out-of-tolerances motion, and record the trajectories for subsequent studies. The system obtains the 3D position of points in space, through its projections in 2D images recorded by two cameras. It tracks black dots on a white sticker placed on the surface of the moving object. The system was tested with linear displacements of a phantom, circular trajectories of a rotating disk, oscillations of an in-house phantom, and oscillations of a 4D phantom. It was also used to track 461 trajectories of points on the surface of patients during their radiotherapy treatments. Trajectories of several points were reproduced with accuracy better than 0.3 mm in the three spatial directions. The system was able to follow periodic motion with amplitudes lower than 0.5 mm, to follow trajectories of rotating points at speeds up to 11.5 cm/s, and to track accurately the motion of a respiratory phantom. The technique has been used to track the motion of patients during radiotherapy and to analyze that motion. The method is flexible. Its installation and calibration are simple and quick. It is easy to use and can be implemented at a very affordable price. Data collection does not involve any discomfort to the patient and does not delay the treatment, so the system can be used routinely in all treatments. It has an accuracy similar to that of other, more sophisticated, commercially available systems. It is suitable to implement a gating system or any other application requiring motion detection, such as 4D CT, MRI or PET.
关键词： motion,radiotherapy,optical,gating
更新于2025-09-23 15:22:29
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Variation of patient imaging doses with scanning parameters for linac-integrated kilovoltage cone beam CT
摘要： To evaluate the Elekta kilovoltage CBCT doses and the associated technical protocols with patient dosimetry estimation. Image guidance technique with cone-beam CT (CBCT) in radiation oncology on a daily basis can deliver a significant dose to the patient. To evaluate the patient dose from LINAC-integrated kV cone beam CT imaging in image-guided radiotherapy. CT dose index (CTDI) were measured with PTW TM30009 CT ion chamber in air, in head phantom and body phantom, respectively; with different combinations of tube voltage, current, exposure time per frame, collimator and gantry rotation range. Dose length products (DLP) were subsequently calculated to account for volume integration effects. The CTDI and DLP were also compared to AcQSim? simulator CT for routine clinical protocols. Both CTDIair and CTDIw depended quadratically on the voltage, while linearly on milliampere x seconds (mAs) settings. It was shown that CTDIw and DLP had very close relationship with the collimator settings and the gantry rotation ranges. Normalized CTDIw for Elekta XVI? CBCT was lower than that of ACQSim simulator CT owing to its pulsed radiation output characteristics. CTDIw can be used to assess the patient dose in CBCT due to its simplicity for measurement and reproducibility. Regular measurement should be performed in QA & QC program. Optimal image parameters should be chosen to reduce patient dose during CBCT.
关键词： CT dose index,image-guided radiotherapy,dose-length product,Cone-beam CT
更新于2025-09-23 15:22:29
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Dosimetric verification of lung phantom calculated by collapsed cone convolution: A?Monte Carlo and experimental evaluation
摘要： OBJECTIVE: To evaluate the dose calculation accuracy in the Prowess Panther treatment planning system (TPS) using the collapsed cone convolution (CCC) algorithm. METHODS: The BEAMnrc Monte Carlo (MC) package was used to predict the dose distribution of photon beams produced by the Oncor? linear accelerator (linac). The MC model of an 18 MV photon beam was verified by measurement using a p-type diode dosimeter. Percent depth dose (PDD) and dose profiles were used for comparison based on three field sizes: 5 × 5, 10 × 10, and 20 × 20cm2. The accuracy of the CCC dosimetry was also evaluated using a plan composed of a simple parallel-opposed field (11 × 16cm2) in a lung phantom comprised of four tissue simulating media namely, lung, soft tissue, bone and spinal cord. The CCC dose calculation accuracy was evaluated by MC simulation and measurements according to the dose difference and 3D gamma analysis. Gamma analysis was carried out through comparison of the Monte Carlo simulation and the TPS calculated dose. RESULTS: Compared to the dosimetric results measured by the Farmer chamber, the CCC algorithm underestimated dose in the planning target volume (PTV), right lung and lung-tissue interface regions by about –0.11%, –1.6 %, and –2.9%, respectively. Moreover, the CCC algorithm underestimated the dose at the PTV, right lung and lung-tissue interface regions in the order of –0.34%, –0.4% and –3.5%, respectively, when compared to the MC simulation. Gamma analysis results showed that the passing rates within the PTV and heterogeneous region were above 59% and 76%. For the right lung and spinal cord, the passing rates were above 80% for all gamma criteria. CONCLUSIONS: This study demonstrates that the CCC algorithm has potential to calculate dose with sufficient accuracy for 3D conformal radiotherapy within the thorax where a significant amount of tissue heterogeneity exists.
关键词： 3D conformal radiotherapy,Monte Carlo,treatment planning,collapsed cone convolution
更新于2025-09-23 15:22:29
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18F-FDG PET/TC para la estadificación y la delineación del volumen de radioterapia en el cáncer de cabeza y cuello
摘要： Purpose: The aim is to investigate the use of 18F-FDG (fluorine-18 fluorodeoxyglucose) PET/CT in head and neck cancer (HNC) staging and its effect on the therapeutic strategy and radiotherapy (RT) planning. Methods and materials: One hundred patients with HNC were included. Primary tumor sites: 18% oral cavity, 20% oropharynx, 12% hypopharynx, 11% nasopharynx, 37% larynx, 2% paranasal sinuses. Patients were staged according to the American Joint Committee of Cancer 7th edition. Stage: 5% stage I, 7% stage II, 14% stage III, 61% stage IVA, 7% stage IVB and 6% stage IVC. A contrast-enhanced CT and a 18F-FDG PET/CT acquired under RT position were performed. Both exams were compared to analyze patients' staging reclassification. Changes in therapeutic strategy were analyzed. Results: 18F-FDG PET/CT detected 6 distant metastases and treatment intention changed to palliative. Eight synchronous tumors were detected; one received palliative treatment. 18F-FDG PET/CT reclassified cTNM staging in 27 patients. Tumor extension changed in 28 (14% up-staged; 14% down-staged), implying a change in GTV (Gross Tumor Volume) delineation. Nodal detection was reclassified in 47 patients: 8 patients down-staged (N2C to N2A/N2B/N1) and 2 were false positive. Nineteen patients were false negatives and 5 staged as N+ (N1/N2A/N2B) turned out into N2C. These staging modifications imply adapting the nodal volume to be irradiated. Conclusions: 18F-FDG PET/CT reclassification was higher than 10% in almost all categories studied (cTNM, tumor extension and nodal disease) and detects more metastases and synchronous tumors than conventional studies, which has an impact on the therapeutic patient management and RT planning.
关键词： Head and neck cancer,18F-FDG PET/CT,Radiotherapy planning,Staging
更新于2025-09-23 15:22:29
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Image-guided study of inter-fraction and intra-fraction set-up variability and margins in reverse semi-decubitus breast radiotherapy
摘要： Background: This study aimed to evaluate the inter-fraction set-up error and intra-fraction motion during reverse semi-decubitus (RSD) breast radiotherapy, and to determine a planning target volume (PTV) margin. Material and methods: Pre- and post-treatment cone-beam computed tomography (CBCT) scans were prospectively acquired at fractions 1, 4, 7, 8, 11, and 14 for 30 patients who underwent RSD breast radiotherapy. Online correction for initial set-up error greater than 5 mm or 2° was performed and post-correction CBCT was acquired. An off-line analysis was performed to quantify initial and residual inter-fraction set-up errors and intra-fraction motion in three-dimensions. Patient inter-fraction errors were analysed for time trends during the course of radiotherapy. PTV margins were calculated from the systematic and random errors. Results: The initial inter-fraction population systematic errors were 1.8–3.3 mm (translation) and 0.5° (rotation); random errors were 1.8–2.1 mm (translation) and 0.3–0.5° (rotation). After online correction, the residual inter-fraction population systematic errors were 1.2–1.8 mm (translation) and 0.3–0.4° (rotation); random errors were 1.4–1.6 mm (translation) and 0.3–0.4° (rotation). Intra-fraction population systematic and random errors were ≤ 1.3 mm (translation) and ≤ 0.2° (rotation). The magnitude of inter-fraction set-up errors in the anterior-posterior direction, roll, and yaw were significantly correlated with higher body weight and body mass index (BMI). The inter-fraction set-up error did not change significantly as a function of time during the course of radiotherapy. The magnitude of intra-fraction motion was not correlated with patient characteristics and treatment time. The total PTV margins accounting for pre-correction and intra-fraction errors were 6.5–10.2 mm; those accounting for post-correction and intra-fraction errors were 4.7–6.3 mm. Conclusions: CBCT is an effective modality to evaluate and improve the inter-fraction set-up reproducibility in RSD breast radiotherapy, particularly for patients with higher BMI. Intra-fraction motion was minimal during RSD breast radiotherapy.
关键词： Inter-fraction reproducibility,Intra-fraction motion,Breast radiotherapy,Reverse semi-decubitus technique
更新于2025-09-23 15:22:29
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Three year experience of electronic portal imaging device based daily QA for photon radiation beams
摘要： An in-house developed EPID based QA strategy was deployed clinically to test daily linac performance before treatment. Beam dosimetric parameters, including output, flatness, symmetry, uniformity, TPR20/10, and MLC repeatability, as well as image quality metrics, such as high and low contrast resolutions, were recorded based on MV and kV EPID imaging analysis. Over a period of three years, data was collected and analyzed. Trend analysis with data visualization, comparisons to ionization chamber (IC) results and QA failure studies were performed to evaluate the reliability and robustness of the EPID based daily QA system. The EPID output tests over the three-year period cross-correlated with the monthly QA IC system within 1.3% and TG51 results within 1%. A consistent positive output drift was detected for all energies during that time. A faster drifting speed was observed after the installation of a new beam monitoring chamber on the machine but slowed down over time. Symmetry, flatness, and uniformity were stable and the changes were directly related to beam steering or QA baseline resetting. TPR20/10 was not sensitive to dosimetry fluctuations and a good delivery repeatability of MLC fields was observed. The image quality metrics were stable and a passing rate greater than 96% was observed. For the most recent eight month of data, a one-time QA passing rate was calculated to be 87.6%. Beam interruptions, human errors and data transfer issues were the major reasons for QA failures. The data gathered over 3 years indicates that the EPID-based process is an efficient and reliable QA solution for daily linac performance checks. The long-term trend analysis and data visualization can help physicists understand the behavior of a linac, optimize the daily QA procedure, and has the potential to predict machine failures prior to incidents.
关键词： daily QA,EPID,photon radiotherapy
更新于2025-09-23 15:22:29
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Multifunctional Nanotheranostic Gold Nanocages for Photoacoustic Imaging Guided Radio/Photodynamic/Photothermal Synergistic Therapy
摘要： In this work, we developed a novel multifunctional nanoplatform based on hyaluronic acid modified Au nanocages (AuNCs-HA). The rational design of AuNCs-HA renders the nanoplatform three functionalities: (1) AuNCs-HA with excellent LSPR peak in the NIR region act as contrast agent for enhanced photoacoustic (PA) imaging and photothermal therapy (PTT); (2) the nanoplatform with high-energy rays (X-ray) absorption and auger electrons generation acts as a radiosensitizer for radiotherapy; (3) good photocatalytic property and large surface area make AuNCs-HA a photosensitive agent for photodynamic therapy (PDT). In vivo results demonstrated that AuNCs-HA presented excellent PA imaging performance after intravenous injection, which provided contour, size, and location information of the tumor. Moreover, because AuNCs-HA could combine radiotherapy and phototherapy together, the tumors treated with AuNCs-HA showed complete growth inhibition, comparing to that with each therapy alone. Taken together, our present study demonstrates that AuNCs-HA is of great potential as a multifunctional nanoplatform for PA imaging-guided radio- and photo-therapy of tumor.
关键词： PTT,Au nanocages,radiotherapy,PDT,theranostic nanoplatform,PA imaging
更新于2025-09-23 15:21:21