OBJECTIVE To investigate the mechanism by which the traditional Chinese medicine formula Xibining Ⅱ modulates cold-stimulus pain sensitivity in rats with cold-damp obstruction-type knee osteoarthritis （KOA） based on the SET domain bifurcated histone lysine methyltransferase 2 （SETDB2）/histone H3 lysine 9 trimethylation （H3K9me3） signaling axis. METHODS Fifty SD rats were randomly divided into control group （intragastric administration and intrathecal injection of equal volumes of normal saline）， model group （intragastric administration and intrathecal injection of equal volumes of normal saline）， Xibining Ⅱ low- and high-dose groups （4， 8 g/kg Xibining Ⅱ， intragastric administration）， and high-dose of Xibining Ⅱ+small interfering RNA （siRNA） group （8 g/kg of Xibining Ⅱ via intragastric administration and intrathecal injection of SETDB2 siRNA at 0.2 mmol/L， 20 μL per rat）， with 10 rats in each group. Except for the control group， cold-damp obstruction-type KOA model was induced in other groups. Drug administration commenced 14 days post-modeling and continued for 28 days. Following the final administration， the following were assessed： behavioral changes in cold-stimulation pain sensitivity， histopathological changes in the articular cartilage of the knee joint， the contents of inflammatory factors [tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β）] and pain mediators [calcitonin gene-related peptide （CGRP）， nerve growth factor （NGF）]， as well as the expressions of SETDB2/H3K9me3 signaling axis，inflammatory factors and pain mediators related proteins and mRNAs in dorsal root ganglion （DRG） tissue. RESULTS After 28 days of drug administration， compared with the model group， Xibining Ⅱ low- and high-dose groups exhibited significantly prolonged cold-stimulus paw withdrawal latency （P＜0.05）； the number of positive responses in the acetone low-temperature test was significantly reduced （P＜0.05）； Mankin score and the Osteoarthritis Research Society International score for knee joint tissue， as well as the levels of inflammatory factors and pain mediators in the serum and their expression in DRG tissue were all significantly decreased （P＜0.05）； the protein expressions of SETDB2 and H3K9me3 in DRG tissue were significantly increased （P＜0.05）. Intrathecal injection of SETDB2 siRNA reversed the above effects of high-dose of Xibining Ⅱ （P＜0.05）. CONCLUSIONS Xibining Ⅱ may alleviate inflammatory and pain responses by activating the SETDB2/H3K9me3 signaling axis， ultimately improving cold-stimulus pain sensitivity in rats with cold-damp obstruction-type KOA.

Objective:To apply statistical process control (SPC) techniques to the quality assurance of non-normal radiotherapy plans through Johnson transformation, establishing patient-specific tolerance and action limits based on treatment sites and dose/distance assessment criteria, thereby enhancing the intensity-modulated radiation therapy (IMRT) verification accuracy and dose delivery precision.Methods:In this study, 951 gamma analysis data of patient-specific quality assurance (PSQA) executed on the Halcyon accelerator platform were selected and categorized into six groups based on treatment sites, including brain (102 cases), head and neck (100 cases), breast (229 cases), lung (154 cases), esophagus (223 cases), and pelvic (143 cases) groups. The six groups of data were statistically analyzed through Anderson-Darling normality tests ( α = 0.05) using Minitab 21 software. Non-normal data were transformed into normal data through Johnson transformation and then were used to establish treatment site-specific tolerance and action limits, which were compared with the Shewhart control charts based on normal distributions. Results:The PSQA result of the six groups all exhibited non-normal distributions ( P < 0.05). Through Johnson transformation, the tolerance and action limits for the head and neck, breast, lung, esophagus, and pelvic areas under the 3%/2 mm criterion ranged from 95.13% to 96.16% and 94.19% to 95.91%, respectively. In contrast, the tolerance and action limits ranged from 91.15% to 94.86% and 89.94% to 94.78% under the 2%/2 mm criterion. Directly applying Shewhart control charts without normality assumptions yielded higher tolerance limits compared to the application of Johnson transformation, increasing the false positive rate in the non-normal PSQA process. Conclusions:Applying the SPC techniques directly to a non-normal process can lead to an increased false alarm rate and wrong process interpretation. The SPC techniques combined with Johnson transformation enable more effective monitoring of a non-normal PSQA process, facilitating timely identification of potential factors that may lead to an out-of-control process based on the treatment site-specific limits.

Objective:To investigate the dose characteristics of the Zeiss INTRABEAM system in air and water, providing dose reference for electronic brachytherapy.Methods:A Monte Carlo program was used to establish a three-dimensional model of a miniature X-ray source vacuum drift tube and a 4 cm spherical applicator. The process of electron beam bombardment on a gold target to generate X-rays was simulated, and parameters such as photon fluence spectrum, percentage depth dose, and half-value layer were calculated. Additionally, the radial dose uniformity in water was measured.Results:The average energy of X-rays at 3 cm in air was 20.8 keV, with a half-value layer of 0.08 mm Al. Under the influence of the applicator, the spectrum becomes hardened, with axial and radial average energies of 28.7 and 29.0 keV, respectively. In water, the percentage depth dose (PDD) curve follows an inverse cubic decay with depth, indicating strong dose concentration and rapid fall-off in near-field irradiation. The radial dose uniformity in water exceeded 99.5%.Conclusions:The INTRABEAM device emits low-energy X-rays characterized by shallow penetration depth, and concentrated dose delivery. Its highly uniform dose distribution ensures comprehensive coverage of the target area, making it particularly suitable for treating superficial tumors and for intraoperative radiotherapy at close range.

Objective:To reveal the coupling mechanism of beam temporal profile and tissue oxygen content on radical kinetics, further explain the potential biological basis of the FLASH effect, and provide a reference for beam optimization and treatment planning design of FLASH radiotherapy (FLASH-RT).Methods:TOPAS-nBio v3.0 was used to simulate the physical and chemical processes of electron beams in water, and a full-scale kinetic model was established covering the generation, diffusion, reaction, and quenching of free radicals such as hydroxyl radical (·OH) and hydrated electrons (e aq-). Under different beam temporal profiles (single pulse, multi-pulses, continuous wave irradiation) and different oxygen concentration conditions, the evolution dynamics of free radicals were systematically simulated. At the same time, the data on e aq- content were obtained by experimental measurement of laser absorption spectroscopy to verify the accuracy of the model prediction. Results:The changing trend of e aq- concentration measured in the experiment was highly consistent with the simulation result, verifying the reliability of the constructed model. The beam time structure had a significant impact on the peak value and duration of free radical concentration. The single-pulse structure can cause the free radicals to rapidly increase and then quickly quench in a short time, while the continuous or long-pulse structure can cause the radical concentration to remain at a high level for a long time. The evolution of ·OH was not sensitive to the oxygen environment, while e aq- are greatly affected by the oxygen environment. The scavenging efficiency of free radicals in a hypoxic environment was significantly decreased, leading to an enhanced accumulation of oxidative damage to biological macromolecules. The lifespan of e aq- in an oxygen-rich environment decreased rapidly. Conclusions:Radical kinetics are regulated by both the beam temporal profile and oxygen content. FLASH-RT can utilize single-pulse or multi-pulses intervals to form periodic windows, reducing normal tissue damage by efficiently scavenging free radicals through antioxidants, while free radicals in tumor tissues continuously accumulate and amplify damage, thus generating a selective protective effect.

Objective:To explore the value of an integrated modeling approach combining radiomics, dosiomics, and clinical factors in the prediction of the locoregional recurrence (LRR) risk after radiotherapy for patients with locoregionally advanced hypopharyngeal squamous cell carcinoma (HPSCC), in order to provide supplementary clinical evidence and decision-making basis for personalized treatment for this rare disease characterized by low incidence and poor prognosis.Methods:The clinical images and pathological data were retrospectively enrolled from 76 HPSCC patients treated at the Peking University Cancer Hospital from October 2011 to July 2020. The planning gross tumor volumes (PGTVs) were taken as the volumes of interest (VOIs). A total of 1 316 radiomic and dosiomic features were extracted from the planning CT and dose distribution images. After stability testing, feature dimensionality reduction was achieved using least absolute shrinkage and selection operator (LASSO) regression and principal component analysis (PCA), with radiomic principal components (RPCs) and dosiomic principal components (DPCs) obtained, respectively. Using various combinations of RPCs, DPCs, and clinical variables as predictors, multivariate Cox regression models were developed after 5-fold cross-validation 100 times. The model performance was evaluated based on the Akaike information criterion (AIC) and concordance index (C-index).Results:Using two RPCs and three DPCs selected, dosiomics and radiomic Cox proportional hazards models were constructed, with C-index values of 0.781 and 0.778 and AIC values of 94.44 and 92.27, respectively. The result indicated that one RPC and three DPCs showed significant associations in Cox regression ( P < 0.05). Other prediction models were established by integrating the clinical data of patients with radiomic features, dosiomic features, or both. The prediction result demonstrated that compared to models based on individual factors or dual components, the multi-omics model yielded the highest prediction accuracy (C-index: 0.823, AIC: 84.94). Conclusions:Integrated models that combine radiomic features, dosiomic features, and clinical factors demonstrate great potential for enhancing the accuracy of LRR risk prediction. These models are expected to provide decision-making support for devising personalized treatment strategies and ultimately improve the prognosis of HPSCC patients.

Objective:To apply statistical process control (SPC) techniques to the quality assurance of non-normal radiotherapy plans through Johnson transformation, establishing patient-specific tolerance and action limits based on treatment sites and dose/distance assessment criteria, thereby enhancing the intensity-modulated radiation therapy (IMRT) verification accuracy and dose delivery precision.Methods:In this study, 951 gamma analysis data of patient-specific quality assurance (PSQA) executed on the Halcyon accelerator platform were selected and categorized into six groups based on treatment sites, including brain (102 cases), head and neck (100 cases), breast (229 cases), lung (154 cases), esophagus (223 cases), and pelvic (143 cases) groups. The six groups of data were statistically analyzed through Anderson-Darling normality tests ( α = 0.05) using Minitab 21 software. Non-normal data were transformed into normal data through Johnson transformation and then were used to establish treatment site-specific tolerance and action limits, which were compared with the Shewhart control charts based on normal distributions. Results:The PSQA result of the six groups all exhibited non-normal distributions ( P < 0.05). Through Johnson transformation, the tolerance and action limits for the head and neck, breast, lung, esophagus, and pelvic areas under the 3%/2 mm criterion ranged from 95.13% to 96.16% and 94.19% to 95.91%, respectively. In contrast, the tolerance and action limits ranged from 91.15% to 94.86% and 89.94% to 94.78% under the 2%/2 mm criterion. Directly applying Shewhart control charts without normality assumptions yielded higher tolerance limits compared to the application of Johnson transformation, increasing the false positive rate in the non-normal PSQA process. Conclusions:Applying the SPC techniques directly to a non-normal process can lead to an increased false alarm rate and wrong process interpretation. The SPC techniques combined with Johnson transformation enable more effective monitoring of a non-normal PSQA process, facilitating timely identification of potential factors that may lead to an out-of-control process based on the treatment site-specific limits.

Objective:To investigate the dose characteristics of the Zeiss INTRABEAM system in air and water, providing dose reference for electronic brachytherapy.Methods:A Monte Carlo program was used to establish a three-dimensional model of a miniature X-ray source vacuum drift tube and a 4 cm spherical applicator. The process of electron beam bombardment on a gold target to generate X-rays was simulated, and parameters such as photon fluence spectrum, percentage depth dose, and half-value layer were calculated. Additionally, the radial dose uniformity in water was measured.Results:The average energy of X-rays at 3 cm in air was 20.8 keV, with a half-value layer of 0.08 mm Al. Under the influence of the applicator, the spectrum becomes hardened, with axial and radial average energies of 28.7 and 29.0 keV, respectively. In water, the percentage depth dose (PDD) curve follows an inverse cubic decay with depth, indicating strong dose concentration and rapid fall-off in near-field irradiation. The radial dose uniformity in water exceeded 99.5%.Conclusions:The INTRABEAM device emits low-energy X-rays characterized by shallow penetration depth, and concentrated dose delivery. Its highly uniform dose distribution ensures comprehensive coverage of the target area, making it particularly suitable for treating superficial tumors and for intraoperative radiotherapy at close range.

Objective:To reveal the coupling mechanism of beam temporal profile and tissue oxygen content on radical kinetics, further explain the potential biological basis of the FLASH effect, and provide a reference for beam optimization and treatment planning design of FLASH radiotherapy (FLASH-RT).Methods:TOPAS-nBio v3.0 was used to simulate the physical and chemical processes of electron beams in water, and a full-scale kinetic model was established covering the generation, diffusion, reaction, and quenching of free radicals such as hydroxyl radical (·OH) and hydrated electrons (e aq-). Under different beam temporal profiles (single pulse, multi-pulses, continuous wave irradiation) and different oxygen concentration conditions, the evolution dynamics of free radicals were systematically simulated. At the same time, the data on e aq- content were obtained by experimental measurement of laser absorption spectroscopy to verify the accuracy of the model prediction. Results:The changing trend of e aq- concentration measured in the experiment was highly consistent with the simulation result, verifying the reliability of the constructed model. The beam time structure had a significant impact on the peak value and duration of free radical concentration. The single-pulse structure can cause the free radicals to rapidly increase and then quickly quench in a short time, while the continuous or long-pulse structure can cause the radical concentration to remain at a high level for a long time. The evolution of ·OH was not sensitive to the oxygen environment, while e aq- are greatly affected by the oxygen environment. The scavenging efficiency of free radicals in a hypoxic environment was significantly decreased, leading to an enhanced accumulation of oxidative damage to biological macromolecules. The lifespan of e aq- in an oxygen-rich environment decreased rapidly. Conclusions:Radical kinetics are regulated by both the beam temporal profile and oxygen content. FLASH-RT can utilize single-pulse or multi-pulses intervals to form periodic windows, reducing normal tissue damage by efficiently scavenging free radicals through antioxidants, while free radicals in tumor tissues continuously accumulate and amplify damage, thus generating a selective protective effect.

Objective:To explore the value of an integrated modeling approach combining radiomics, dosiomics, and clinical factors in the prediction of the locoregional recurrence (LRR) risk after radiotherapy for patients with locoregionally advanced hypopharyngeal squamous cell carcinoma (HPSCC), in order to provide supplementary clinical evidence and decision-making basis for personalized treatment for this rare disease characterized by low incidence and poor prognosis.Methods:The clinical images and pathological data were retrospectively enrolled from 76 HPSCC patients treated at the Peking University Cancer Hospital from October 2011 to July 2020. The planning gross tumor volumes (PGTVs) were taken as the volumes of interest (VOIs). A total of 1 316 radiomic and dosiomic features were extracted from the planning CT and dose distribution images. After stability testing, feature dimensionality reduction was achieved using least absolute shrinkage and selection operator (LASSO) regression and principal component analysis (PCA), with radiomic principal components (RPCs) and dosiomic principal components (DPCs) obtained, respectively. Using various combinations of RPCs, DPCs, and clinical variables as predictors, multivariate Cox regression models were developed after 5-fold cross-validation 100 times. The model performance was evaluated based on the Akaike information criterion (AIC) and concordance index (C-index).Results:Using two RPCs and three DPCs selected, dosiomics and radiomic Cox proportional hazards models were constructed, with C-index values of 0.781 and 0.778 and AIC values of 94.44 and 92.27, respectively. The result indicated that one RPC and three DPCs showed significant associations in Cox regression ( P < 0.05). Other prediction models were established by integrating the clinical data of patients with radiomic features, dosiomic features, or both. The prediction result demonstrated that compared to models based on individual factors or dual components, the multi-omics model yielded the highest prediction accuracy (C-index: 0.823, AIC: 84.94). Conclusions:Integrated models that combine radiomic features, dosiomic features, and clinical factors demonstrate great potential for enhancing the accuracy of LRR risk prediction. These models are expected to provide decision-making support for devising personalized treatment strategies and ultimately improve the prognosis of HPSCC patients.

AIM:To investigate whether Xibining Ⅱ(XBN Ⅱ)attenuates cartilage damage in rats with knee osteoarthritis(KOA)by modulating glycolysis via the AMP-activated protein kinase(AMPK)/peroxisome proliferator-acti-vated receptor γ coactivator 1α(PGC1α)signaling pathway.METHODS:Thirty-two SD rats were randomly divided into sham group,KOA group,XBN Ⅱ group and metformin(AMPK activator)group,with 8 rats in each group.The rats in KOA group were subjected to the anterior cruciate ligament transection procedure to establish the KOA model.Starting from the 14th day after modeling,the rats in XBN Ⅱ group received a daily dose of XBN Ⅱ via gavage once a day,and those in metformin group were administered metformin via intraperitoneal injection once a day for 4 weeks.Subsequently,the histopathological changes of the cartilage were examined by HE and safranin O-fast green staining with matching Mankin and OARSI scores.The protein levels of phosphorylated AMPK(p-AMPK)and PGC1α in cartilage were quanti-fied through immunohistochemistry.In addition,RT-qPCR and Western blot were conducted to measure the mRNA and protein expression levels of glycolysis-related factors,including glucose transporter 1,hexokinase 2 and lactate dehydroge-nase A,biomarkers related to cartilage synthesis and catabolism,such as collagen type Ⅱ,aggrecan,matrix metallopro-teinase 13 and a disintegrin and metalloproteinase with thrombospondin motifs 5,and AMPK/PGC1α signaling pathway-re-lated indicators.RESULTS:Lactate levels in cartilage and serum were higher in KOA group compared with sham group(P<0.05).Similarly,the cartilage in KOA group exhibited significant surface abrasion and structural damage,with faint-stained matrix and significantly higher Mankin and OARSI scores compared with sham group(P<0.05).Further analysis revealed significant decreases in the mRNA and protein expression levels of factors related to cartilage anabolism and AMPK/PGC1α signaling pathway in KOA group compared with sham group(P<0.05).In contrast,there were marked in-creases in the mRNA and protein expression levels of factors related to cartilage catabolism and glycolysis(P<0.05).No-tably,XBN Ⅱ and metformin treatments significantly improved the cartilage morphology,reduced Mankin and OARSI scores,and reversed the changes in mRNA and protein levels of the aforementioned indexes(P<0.05).CONCLU-SION:Treatment with XBN Ⅱ can alleviate cartilage damage in KOA rats by inhibiting glycolysis,through a mechanism involving activation of the AMPK/PGC1α signaling pathway.