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Boosting the Radiosensitizing and Photothermal Performance of Cu <sub/>2-x</sub> Se Nanocrystals for Synergetic Radiophotothermal Therapy of Orthotopic Breast Cancer
摘要： The small difference between tumor and normal tissues in their responses to ionizing radiation has been a significant issue for radiotherapy of tumors. Herein, we report that dumbbell-shaped heterogeneous copper selenide-gold nanocrystals can serve as an efficient radiosensitizer for enhanced radiotherapy. The mean lethal dose of X-rays to 4T1 tumor cells can be drastically decreased about 40%, i.e., decreasing from 1.81 Gy to 1.10 Gy after culture with heterostructures. Due to the synergetic effect of heterostructures, the dose of X-rays is also much lower than those obtained from mixture of Cu2-xSe + Au nanoparticles (1.78 Gy), Cu2-xSe nanoparticles (1.72 Gy) and Au nanoparticles (1.50 Gy), respectively. We demonstrate that the sensitivity enhancement ratio of Cu2-xSe nanoparticles was significantly improved 45% (i.e., from 1.1 to 1.6) after the formation of heterostructures with gold. We also show that the hetero-nanocrystals exhibit an enhanced photothermal conversion efficiency, due to the synergetic interactions of localized surface plasmon resonance. These properties highly feature them as a multimodal imaging contrast agent (particular for photoacoustic imaging, computed tomography imaging, and single photon emission computed tomography after labeled with radioisotopes) and as a radiosensitizer for imaging guided synergetic radiophotothermal treatment of cancer. The research provides insights for engineering low-Z nanomaterials with high Z elements to form hetero-nanostructures with enhanced synergetic performance for tumor theranostics.
关键词： radiosensitizer,multimodal imaging,radiotherapy,heterogeneous nanoparticles,photothermal therapy
更新于2025-09-19 17:15:36
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Raman profile alterations of irradiated human nasopharyngeal cancer cells detected with laser tweezer Raman spectroscopy
摘要： Radiotherapy has been widely used for nasopharyngeal carcinoma (NPC) treatment, which causes DNA damage and alterations of macromolecules of cancer cells. However, the Raman profile alterations of irradiated NPC cells remain unclear. In the present study, we used laser tweezers Raman spectroscopy (LTRS) to monitor internal structural changes and chemical modifications in NPC cells after exposure at a clinical dose (2.3 Gy) to X-ray irradiation (IR) at a single-cell level. Two types of NPC cell lines, CNE2 (EBV-negative cell line) and C666-1 (EBV-positive cell line), were used. The Raman spectra of cells before and after radiation treatment were recorded by LTRS. The analysis of spectral differences indicated that the IR caused Raman profile alterations of intracellular proteins, DNA base and lipids. Moreover, by using the multivariate statistical analysis including principal component analysis (PCA) and linear discriminant analysis (LDA) algorithm, an accuracy of 90.0% for classification between CNE2 cells before and after IR could be achieved, which was 10% better than that of C666-1 cells. The results demonstrated that CNE2 cells were more sensitive to IR in comparison to C666-1 cells, providing useful information for creating a treatment strategy in clinical practice. This exploratory study suggested that LTRS combined with multivariate statistical analysis would be a novel and effective tool for evaluating the radiotherapeutic effect on tumor cells, and for detection of the corresponding alterations at the molecular level.
关键词： laser tweezers,multivariate statistical analysis,nasopharyngeal carcinoma,radiotherapy,Raman spectroscopy
更新于2025-09-19 17:13:59
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Radiology, Lasers, Nanoparticles and Prosthetics || 11. Neutron radiotherapy
摘要： Neutrons like protons are hadrons, however neutrons are uncharged. They are more difficult to produce, and because they are neutral, accelerators and magnets cannot be used for tuning their energy or steering the beam. Neutron irradiation requires a neutron source and a radiological shielding environment that are very different to those for charged particles. Among the various external radiation treatments of cancer, neutron radiation therapy is presently not often prescribed.
关键词： fast neutrons,RBE,Boron Neutron Capture Therapy,BNCT,linear energy transfer,Neutron radiotherapy,LET,relative biological effectiveness
更新于2025-09-16 10:30:52
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Radiotherapy mucositis in head and neck cancer: prevention by low-energy surface laser
摘要： background Modern radiotherapy (RT) planning techniques and the use of oral supportive care have reduced the occurrence of acute radiation-induced toxicities. Oral mucositis remains a major concern in patients with head and neck cancer as it can compromise treatment compliance and outcome. Objective To report the rate of mucositis with the preventive use of surface low-level laser therapy in patients with head and neck cancer. Methods Forty patients treated with definitive (n=27) or adjuvant (n=13) RT using volumetric arc therapy between August 2014 and October 2015 for squamous cell carcinoma of the head and neck were included. All patients were treated using photobiomodulation using surface low-level laser therapy (Heltschl kind FL 3500, 350 mW), 3 times a week during the whole treatment course. The grade of mucositis was obtained from week 1 to week 7 and at 1 month. results The median RT dose was 70 Gy (64–70). Concomitant chemotherapy was administered in 29 patients. According to the Common Terminology Criteria for Adverse Events (CTCAE) v. 3, grade 0, 1, 2 and 3 mucositis was observed in 9 (22.5%), 9 (22.5%), 16 (40%) and 6 (15%) patients at week 7, and 32 (80%), 2 (5%), 3 (7.5%) and 3 (7.5%) patients at 1 month following treatment. No grade 4 occurred. Median average and maximum dose to the oral mucosa was 42 Gy (12.9–66.3) and 66.6 Gy (39–76), respectively. conclusion Despite a substantial dose to the oral mucosa, the rate of acute radiation-induced mucositis of grade ≥3 remains low in patients receiving extraoral low-energy laser during RT.
关键词： radiotherapy,mucositis,prevention,low-energy surface laser,head and neck cancer
更新于2025-09-16 10:30:52
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<sup>131</sup> I‐Labeled Multifunctional Polyphosphazene Nanospheres for SPECT Imaging‐Guided Radiotherapy of Tumors
摘要： Design of theranostic nanoplatforms represents a major topic for current nanomedicine. Here, the preparation of multifunctional poly(cyclotriphosphazene-co-polyethylenimine) nanospheres (PNSs) labeled with radionuclide 131I for single photon emission computed tomography (SPECT) imaging-guided radiotherapy of tumors is reported. In this work, PNSs are prepared using hexachlorocyclotriphosphazene as a crosslinker to crosslink branched polyethylenimine (PEI) via a nucleophilic substitution reaction, modified with 3-(4′-hydroxyphenyl) propionic acid-OSu (HPAO) for 131I labeling, and reacted with 1,3-propane sulfonate (1,3-PS) to render the particles with antifouling property, followed by acetylation of the remaining surface amines and labeling with 131I. The acquired PNS.NHAc-HPAO(131I)-PS particles are well characterized. It is shown that the multifunctional PNSs with an average size of 184 ± 29.3 nm exhibit favorable antifouling properties, high 131I labeling efficiency (76.05 ± 3.75%), and excellent radiostability and colloidal stability. With these properties owned, the developed PNS.NHAc-HPAO(131I)-PS spheres enable much more efficient SPECT imaging and radiotherapy of a xenografted tumor model in vivo than the PEI counterpart material (PEI.NHAc-HPAO(131I)-PS). The developed PNSs may be used as a versatile platform for further development of different forms of nanomedicine for various biomedical applications.
关键词： polyphosphazene,radiotherapy,tumors,nanospheres,SPECT imaging
更新于2025-09-12 10:27:22
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Photonuclear production of medical isotopes <sup>62,64</sup> Cu using intense laser-plasma electron source
摘要： 62,64Cu are radioisotopes of medical interest that can be used for positron emission tomography (PET) imaging. Moreover, 64Cu has β? decay characteristics that allow for targeted radiotherapy of cancer. In the present work, a novel approach to experimentally demonstrate the production of 62,64Cu isotopes from photonuclear reactions is proposed in which large-current laser-based electron (e?) beams are generated from the interaction between sub-petawatt laser pulses and near-critical-density plasmas. According to simulations, at a laser intensity of 3.4 × 1021 W/cm2, a dense e? beam with a total charge of 100 nC can be produced, and this in turn produces bremsstrahlung radiation of the order of 1010 photons per laser shot, in the region of the giant dipole resonance. The bremsstrahlung radiation is guided to a natural Cu target, triggering photonuclear reactions to produce the medical isotopes 62,64Cu. An optimal target geometry is employed to maximize the photoneutron yield, and 62,64Cu with appropriate activities of 0.18 GBq and 0.06 GBq are obtained for irradiation times equal to their respective half-lives multiplied by three. The detection of the characteristic energy for the nuclear transitions of 62, 64Cu is also studied. The results of our calculations support the prospect of producing PET isotopes with gigabecquerel-level activity (equivalent to the required patient dose) using upcoming high-intensity laser facilities.
关键词： 62,64Cu,laser-plasma electron source,medical isotopes,Photonuclear production,targeted radiotherapy,PET imaging
更新于2025-09-12 10:27:22
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Retrospective evaluation of the safety of low-level laser therapy/photobiomodulation in patients with head/neck cancer
摘要： Background The standard therapeutic approach for locally advanced head and neck cancer is optimal use of radiation therapy with or without concomitant chemotherapy. The most common and distressing acute complication of such therapies is oral/pharyngeal mucositis that may be associated with severe morbidity and can interfere with the planned administration of therapy. Methods We have identified all patients diagnosed with head/neck cancer between 2005 and 2009, having received radiotherapy with or without cisplatin-based chemotherapy. Radiotherapy consisted of intensity-modulated radiation therapy (IMRT) in all patients. In patients with grade > 2 mucositis, photobiomodulation (PBM) consisted of three sessions of low-level laser irradiation weekly, in accordance with recently published recommendations for PBM. Patients who did not receive PBM were those for whom that approach was not requested by the radiotherapists and those who declined it. Results Two hundred twenty-two patients (62%) received PBM and 139 did not (39%). The patient’s characteristics were equally distributed between the two groups. For overall survival, time to local recurrence, and progression-free survival, there was no statistical evidence for a difference in prognosis between patients with and without PBM. In a multivariate analysis, after adjusting for known prognostic factors, we found no statistical evidence that PBM was related to overall survival, progression-free survival, or local recurrence. Conclusions Our results show evidence of no effect of PBM upon overall survival, time to local recurrences, and disease-free survival of patients with head and neck cancer treated with radiotherapy with/without chemotherapy.
关键词： Head/neck cancer,Oral mucositis,Radiotherapy,Prevention,Photobiomodulation,Laser therapy
更新于2025-09-11 14:15:04
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Radiology, Lasers, Nanoparticles and Prosthetics || 8. Cell cycle and cancer
摘要： The present chapter is intended to provide a basic understanding of the cell’s life cycle and the difference between normal and cancerous cells. This information is a prerequisite for the rationale behind cancer treatment plans using radiotherapy discussed in Chapters 9–12. For more specific and detailed information on cell cycle the reader is referred to standard biology [1] or physiology textbooks listed under “Further reading”. Here we focus the discussion on the relation between dose and cell survival rate that is contextual information for the following chapters on radiotherapy.
关键词： radiation response,biological effectiveness,cell cycle,DNA replication,mitosis,oncogenes,apoptosis,tumor suppressors,fractionation,hypoxia,chemotherapy,radiotherapy,cancer
更新于2025-09-11 14:15:04
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A simple jig for the anti-parallel alignment of linacs’ lasers
摘要： Background: Despite crossing at the isocentre, misaligned laser beams may cause significant positioning problems. Purpose: The jig proposed here is to be used in addition to the quality assurance procedures employed with linacs and deals with possible misalignments of transverse lasers. Materials and methods: It is an inverted T construction with a two-sided rectangular, slightly transparent mirror set vertical on a piece of glass serving as its base. The device is carried by a horizontally set spirit-level surface and placed on the couch-top so that the sagittal laser passes through the vertical mirror’s plane. Then the therapy couch is translated along the Y direction until a laser beam shines on the corresponding side of the semi-transparent mirror. This spot is marked and is normally the linac’s isocentre set through an independent procedure employing a rotating plate. If the laser had been set properly, then its beam should be reflecting back on its source. If not, the alignment can be corrected by rotating and/or translating the laser holder until it does that. At the same time, it should be ensured that the beam does not wander away from the isocentre spot on the mirror. When both are achieved, the beam ends up perpendicular to the linac’s axis of rotation, while passing through the isocentre. The procedure can be repeated for the opposite laser. Conclusion: The jig was simple to construct and has been found quite useful in practice. The accuracy of patient positioning will be restricted only by the size of the laser beam’s cross-section.
关键词： laser alignment,patient positioning,radiotherapy,laser beam set up
更新于2025-09-11 14:15:04
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Optical Surface Scanning for Patient Positioning in Radiation Therapy: A Prospective Analysis of 1902 Fractions
摘要： Purpose/Objective: Reproducible patient positioning remains one of the major challenges in modern radiation therapy. Recently, optical surface scanners have been introduced into clinical practice in addition to well-established positioning systems, such as room laser and skin marks. The aim of this prospective study was to evaluate setup errors of the optical surface scanner Catalyst HD (C-RAD AB) in different anatomic regions. Material/Methods: Between October 2016 and June 2017 a total of 1902 treatment sessions in 110 patients were evaluated. The workflow of this study included conventional setup procedures using laser-based positioning with skin marks and an additional registration of the 3-dimensional (3D) deviations detected by the Catalyst system. The deviations of the surface-based method were then compared to the corrections of cone beam computed tomography alignment which was considered as gold standard. A practical Catalyst setup error was calculated between the translational deviations of the surface scanner and the laser positioning. Two one-sided t tests for equivalence were used for statistical analysis. Results: Data analysis revealed total deviations of 0.09 mm + 2.03 mm for the lateral axis, 0.07 mm + 3.21 mm for the longitudinal axis, and 0.44 mm + 3.08 mm vertical axis for the Catalyst system, compared to (cid:2)0.06 + 3.54 mm lateral, 0.53 + 3.47 mm longitudinal, and 0.19 + 3.49 mm vertical for the laser positioning compared to cone beam computed tomography. The lowest positional deviations were found in the cranial region, and larger deviations occurred in the thoracic and abdominal sites. A statistical comparison using 2 one-sided t tests showed a general concordance of the 2 methods (P (cid:3) 0.036), excluding the vertical direction of the abdominal region (P ? 0.198). Conclusion: The optical surface scanner Catalyst HD is a reliable and feasible patient positioning system without any additional radiation exposure. From the head to the thoracic and abdominal region, a decrease in accuracy was observed within a comparable range for Catalyst and laser-assisted positioning.
关键词： patient positioning,surface scanner,laser positioning,CBCT,radiotherapy,catalyst
更新于2025-09-10 09:29:36