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A dosimetric study on the use of 3D-printed customized boluses in photon therapy: A hydrogel and silica gel study
摘要： Purpose: The aim of the study was to compare the dose differences between two kinds of materials (silica gel and hydrogel) used to prepare boluses based on three‐dimensional (3D) printing technologies and commercial bolus in head phantoms simulating nose, ear, and parotid gland radiotherapy. Methods and materials: We used 3D printing technology to make silica gel and hydrogel boluses. To evaluate the clinical feasibility, intensity modulated radiation therapy (IMRT) plans were created for head phantoms that were bolus‐free or had a commercial bolus, a silica gel bolus, or a hydrogel bolus. Dosimetry differences were compared in simulating nose, ear, and parotid gland radiotherapy separately. Results: The air gaps were smaller in the silica gel and hydrogel bolus than the commercial one. In nose plans, it was shown that the V95% (relative volume that is covered by at least 95% of the prescription dose) of the silica gel (99.86%) and hydrogel (99.95%) bolus were better than the commercial one (98.39%) and bolus‐free (87.52%). Similarly, the homogeneity index (HI) and conformity index (CI) of the silica gel (0.06; 0.79) and hydrogel (0.058; 0.80) bolus were better than the commercial one (0.094; 0.72) and bolus‐free (0.59; 0.53). The parameters of results (HI, CI, V95%) were also better in 3D printing boluses than in the commercial bolus or without bolus in ear and parotid plans. Conclusions: Silica gel and hydrogel boluses were not only good for fit and a high level of comfort and repeatability, but also had better parameters in IMRT plans. They could replace the commercial bolus for clinical use.
关键词： hydrogel,silica gel,radiotherapy,tissue compensator,3D printing
更新于2025-09-23 15:21:21
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A Multiport Converter Interfacing Solar Photovoltaic Modules and Energy Storage with DC Microgrid
摘要： A novel real-time optical fibre X-Ray dosimeter for monitoring the radiation pulses delivered from a clinical linear accelerator (Linac) is presented. The primary focus of the sensor is to measure low doses of ionising X-ray radiation in real time (limited to 0.1-ms gate time of the detector). The sensor tip material scintillates upon exposure to X-ray energy and the resultant low-level visible light signal is coupled to a polymethyl methacrylate plastic optical fibre, which is used to guide it towards a distal avalanche photodiode-based detector. The detector measures the low-level scintillating light from the sensor, thereby converting the ionizing radiation energy to a measurable signal with a time resolution of 0.1 ms. Results show that the scintillating optical fibre X-ray dosimeter is capable of capturing the individual X-Ray pulses delivered by the Linac during normal operation. Further examination of the results demonstrates that the sensor is capable of measuring dose rate and, hence, dose with a linearity (R2 = 0.9995 ? 0.9999) and in a highly repeatable manner for dose rates in the range 100 to 600 monitor units/min.
关键词： optical fibre sensors,X-ray dosimetry,Clinical external beam radiotherapy,fluorescent and luminescent sensors,real time radiation dose measurement
更新于2025-09-23 15:21:01
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Combined temperature and radiation effects on radiation sensitive single-mode optical fibers
摘要： A novel real-time optical fibre X-Ray dosimeter for monitoring the radiation pulses delivered from a clinical linear accelerator (Linac) is presented. The primary focus of the sensor is to measure low doses of ionising X-ray radiation in real time (limited to 0.1-ms gate time of the detector). The sensor tip material scintillates upon exposure to X-ray energy and the resultant low-level visible light signal is coupled to a polymethyl methacrylate plastic optical fibre, which is used to guide it towards a distal avalanche photodiode-based detector. The detector measures the low-level scintillating light from the sensor, thereby converting the ionizing radiation energy to a measurable signal with a time resolution of 0.1 ms. Results show that the scintillating optical fibre X-ray dosimeter is capable of capturing the individual X-Ray pulses delivered by the Linac during normal operation. Further examination of the results demonstrates that the sensor is capable of measuring dose rate and, hence, dose with a linearity (R2 = 0.9995 ? 0.9999) and in a highly repeatable manner for dose rates in the range 100 to 600 monitor units/min.
关键词： optical fibre sensors,X-ray dosimetry,Clinical external beam radiotherapy,fluorescent and luminescent sensors,real time radiation dose measurement
更新于2025-09-23 15:21:01
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Intraoperative radiotherapy with low energy photons in recurrent colorectal cancer: a single centre retrospective study
摘要： Aim of the study: Intraoperative radiotherapy (IORT) may improve outcome of surgical treatment of recurrent colorectal cancer (CRC). The aim of this study is to determine the feasibility, safety and long-term results of surgical treatment of recurrent CRC with orthovolt IORT. Material and methods: Fifty-nine consecutive CRC patients with local recurrence (LR), undergoing surgery, were included in the retrospective analysis of prospectively collected data. The modified Wanebo classification was used to stage LR (Tr). Twenty-five (43%) patients received IORT using INTRABEAM? PRS 500. The complications were classified according to the Clavien-Dindo classification. Results: There were 32 males and 27 females, with a median age of 63 years. Multi-visceral resections were performed in 37 (63%) patients. Median hospitalization time after surgery with IORT was 7 days. One (1.7%) in-hospital postoperative death was reported. Grade 3/4 postoperative complications were found in 11 (19%) patients. Intraoperative radiotherapy had no effect on the postoperative hospitalization time, morbidity and mortality. Median survival after R0 resection was 32 months. Complete resection (R0), no synchronous liver metastases (M0), and no lateral and posterior pelvic wall involvement, were significant predictors of improved survival. Stage of LR was found to be an independent prognostic factor in the multivariate analysis (p = 0.03; Cox regression model). In patients with LR stage < Tr5, a 3-year overall survival (OS) rate was 52%. Conclusions: Combination of surgical resection and orthovolt IORT is a safe and feasible procedure that does not increase the risk of postoperative complications or prolongs the hospital stay. Despite aggressive surgery supported by IORT, the advanced stage of LR is a limiting factor of long-term survival.
关键词： colorectal cancer,recurrence,intraoperative radiotherapy,survival,surgery
更新于2025-09-23 15:21:01
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Nanostructures for Cancer Therapy || Dose enhancement effect in radiotherapy: adding gold nanoparticles to tumor in cancer treatment
摘要： The rationale of radiation dose enhancement due to gold nanoparticle addition in radiotherapy is revealed from the basic particle interactions to Monte Carlo simulation. Our review of different radiobiological studies on Monte Carlo, cell line, and preclinical model confirms that cancer cell kill definitely benefits from the dose enhancement when gold nanoparticles were added. Moreover, such dose enhancement depends on the size, shape, and concentration of the gold nanoparticle, as well as the type and energy of the radiation beams. It is concluded that adding gold nanoparticles to the tumor can enhance both the dose and contrast at the target in radiotherapy.
关键词： radiotherapy,cancer treatment,Monte Carlo simulation,gold nanoparticles,dose enhancement
更新于2025-09-23 15:21:01
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One-stop radiotherapeutic targeting of primary and distant osteosarcoma to inhibit cancer progression and metastasis using 2DG-grafted graphene quantum dots
摘要： The application of radiotherapy (RT) to treat osteosarcoma (OS) has been limited, but this is starting to change as the ability to target radiation energy to niches improves. Further, lung cancer from highly metastatic OS is a major cause of death, so it is critical to explore new strategies to tackle metastasis. In this study, we designed a nanoscale radiosensitizer by grafting 2-deoxy-d-glucose (2DG) on to graphene quantum dots (GQD) to achieve OS targeting and boost RT efficacy. Combining the use of 2DG-grafted GQDs (2DG-g-GQD) with RT produced a significant increase in oxidative stress response and DNA damage in the 143B OS cell line compared with RT alone. Moreover, 2DG-g-GQDs selectively associated with 143B cells, and demonstrated inhibition of migration in a scratch assay. We also demonstrated remarkable improvement in ability to inhibit tumour progression and lung metastasis in an OS xenograft mouse model. Our results show that the use of 2DG-g-GQDs as an OS-targeting radiosensitizer improves the therapeutic outcome and exhibits potential for use in low-dose precision RT for OS.
关键词： osteosarcoma,radiotherapy,metastasis,2-deoxy-d-glucose,graphene quantum dots
更新于2025-09-23 15:19:57
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Outcome of a 980-nm diode laser coagulation in women with radiation-induced hemorrhagic cystitis: a single-center retrospective study
摘要： The purpose of this study was to evaluate the efficacy of a 980-nm diode laser coagulation in women with radiation-induced hemorrhagic cystitis (RHC). We conducted a retrospective study of 21 RHC patients treated with a 980-nm diode laser between July 2014 and December 2017 at our institution. Data was collected with regard to age, sex, lower urinary tract symptoms, use of transfusions, a drop in hemoglobin levels, indication of radiotherapy, median time between radiation therapy and presentation, previous treatments, operative time, mean energy used, number of coagulated areas, catheterization time, discharge time after treatment, hospital stay, and surgical outcome. All 21 patients were women with a median age of 52 years (range 36–68 years). Eighteen patients complained of frequency and urgency, four patients had dysuria, and one patient developed urinary retention. Radiation therapy was primarily indicated in the treatment of cervical cancer in 18 patients (85.7%) and endometrial cancer in three patients (14.3%). Nine patients (42.8%) received blood transfusion before surgery and three patients (14.3%) needed blood transfusion after the procedure. The mean decrease in hemoglobin prior to the procedure was 4.08 ± 2.04 g/dL. The median length of time from completion of radiotherapy to the presentation of hematuria was 38 months (range 8–65 months). All patients had failed an adequate trial of conservative treatment which included adequate hydration, hemostatics, continuous bladder irrigation (CBI), and clot evacuation at the bedside. Eleven patients (52.4%) had previously been treated with endoscopic electrocoagulation; the mean number of procedures was 1.73 ± 0.78 (range 1–3 sessions). Six patients (28.6%) underwent HBO, and sodium hyaluronate solution irrigation was administered to 3 patients (14.3%). The mean number of HBO sessions was 26.3 ± 16.8 (range 8–50), and the mean number of sodium hyaluronate solution irrigation procedures was 4.33 ± 1.53 (range 3–6). All operations were successful. The mean operative time was 45.6 ± 12.3 min, the mean number of coagulated areas was 11.7 ± 4.4, the mean energy used was 2.74 ± 1.14 kJ, the mean catheterization time was 6.2 ± 0.9 days, the mean discharge time after treatment was 6.8 ± 1.2 days, and the average length of a hospital stay was 7.4 ± 1.3 days. In 16 patients (76.2%), hematuria was completely resolved after one session of diode laser coagulation. Four patients (19.0%) underwent multiple sessions of laser treatment due to recurrent gross hematuria (three patients required two sessions and one patient required three sessions). Only one patient (4.8%) who had persistent gross hematuria after diode laser treatment (two sessions) underwent a radical cystectomy, which resolved the hematuria. The median hematuria-free interval of patients who had multiple procedures was 9 months (range 1–13 months). In total, 21 patients underwent 27 sessions of diode laser coagulation, and the median hematuria-free interval was 16 months (range 1–45 months) with a median follow-up of 25 months (range 7–48 months). Our study shows promising results for the management of patients with RHC; however, further evaluation with a larger cohort is required to confirm the efficacy of this treatment.
关键词： Diode lasers,Treatment outcome,Radiotherapy,Cystitis
更新于2025-09-23 15:19:57
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Efetividade profil??tica e terap?autica do laser de baixa intensidade na mucosite bucal em pacientes submetidos ao tratamento do c?￠ncer
摘要： Objective: the purpose of this review is to present the different randomized clinical protocols using low level laser in the management of oral mucositis, in the last eighteen years of study. Literature review: oral mucositis remains a major problem to be solved in clinical oncology. This cytotoxic effect limits food intake by mouth due to the pain and discomfort in chewing and/or swallowing. Nutritional status may be aggravated contributing to increased morbidity and hospital stay, and providing negative impact on the quality of life of cancer patients, and on their treatment. Disturbances in the integrity and function of the oral cavity are due to the fact that radiotherapy and chemotherapy are not able to destroy tumor cells without damaging normal cells. Numerous treatments are described in literature and there are several methodologies for the treatment of oral mucositis, yet there is no consensus on the best strategy for prevention and therapy. Final considerations: several studies have shown good results with the use of low level laser, which main indications include anti-inflammatory and analgesic effects, and inducing tissue repair. However, there is no definition of a single protocol for this promising resource so far to be applied in the therapy of this pathology.
关键词： Low level,Laser therapy,Oral mucositis,Chemotherapy,Radiotherapy
更新于2025-09-23 15:19:57
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Reconstruction of X-rays spectra of clinical linear accelerators from transmission data with generalized simulated annealing
摘要： The spectral distribution of megavoltage X-rays used in radiotherapy departments is a fundamental quantity from which, in principle, all relevant information required for radiotherapy treatments can be determined. The direct measurement is di?cult to achieve clinically and analyzing the transmission is a clinically viable indirect method for determining clinical linear accelerators photon spectra. In this method, transmission signals are acquired after the beam passes through di?erent thicknesses of attenuators. The objective of this work was the establishment and application of an indirect method that used a spectral model based on generalized simulated annealing algorithm to determine the spectrum of clinical linear accelerators photons based on the transmission curve. Analysis of the spectra was made by analytical determination of dosimetric quantities and related parameters.
关键词： Spectrometry,Photons,Radiotherapy,Monte Carlo,Generalized simulated annealing
更新于2025-09-23 15:19:57
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CT/MRI-Guided Synergistic Radiotherapy and X-ray Inducible Photodynamic Therapy Using Tb-Doped Gd-W-Nanoscintillators
摘要： The use of X-rays instead of UV/Vis light to trigger photodynamic therapy, named X-ray inducible photodynamic therapy, holds tremendous promise due to a high penetration capacity in tissues and is worthy of in-depth study. In this study, a novel multifunctional nanoagent based on Merocyanine 540-coupled Gd2(WO4)3:Tb nanoscintillators and the vitalization of its abilities for dual-modal computed tomography and the magnetic-resonance-imaging-guided synergistic radio-/X-ray inducible photodynamic therapy of tumors is reported. Synergistic therapies show a higher tumor growth inhibition efficiency at a lower X-ray dose than radiotherapy alone. Through this proof-of-concept work, a way to tactfully understand and utilize nanoscintillators for cancer theranostics is shown.
关键词： nanoscintillators,radiotherapy,magnetic resonance imaging,computed tomography,X-ray inducible photodynamic therapy
更新于2025-09-19 17:15:36