To further explore relative biological effectiveness (RBE) variability, the RBE of different intracerebral cells at various irradiation (IR) dosages and time were determined in this study. A total of 120 rabbits were randomly divided into proton groups (0, 10, 20, 30, 40 Gy, RBE) (n = 3) and photon groups (0, 10, 20, 30, 40 Gy) (n = 3). The rabbits were sacrificed at 2, 4, 6, 8 weeks after brain IR. Neuronal survival, identified via Hematoxylin and Eosin (H&E) staining, and immunohistochemical detection of neurofilament (NF), Olig2, and CD68 in the hippocampus and thalamus, were analyzed. Dose- and time-dependent RBE curves were fitted using the LQ model. Proton IR showed higher neuronal survival at 4-, 6-, and 8-weeks post 10 Gy, 20 Gy, 30 Gy IR (p < 0.05) compared to photon IR. Oligodendrocyte populations in photon group at 4-, 6-, and 8-weeks post 10 Gy IR and 6-, 8-weeks post 20 Gy were consistently higher than proton subgroups (p < 0.05). While proton IR showed higher microglial activation which was observed only at 4-weeks post 30y IR. Proton RBE for neurons and oligodendrocytes remained below 1.1 but exceeded 1.1 for microglial activation. These findings demonstrate the dose- and time- dependent nature of proton RBE and suggest brain tissue tolerates higher proton IR doses compared to photon IR, which fully confirmed the biological advantages of proton IR. These will help clinicians more precisely set the organ limit at risk and tailor radiotherapy plans.

Background:Pancreatic cancer is characterized by an insidious onset and rapid progression, and the accurate determination of the gross tumor volume (GTV) constitutes a critical prerequisite for ensuring the efficacy of radiotherapy. Multiphase contrast-enhanced magnetic resonance imaging (CE-MRI) enables the dynamic visualization of tumor hemodynamic perfusion characteristics; however, the tissue discrimination capability varies substantially across different enhancement phases. To date, there is no universal consensus on the optimal imaging phase for GTV determination in pancreatic cancer. This study aimed to quantitatively analyze the differences in imaging and GTV determination of pancreatic cancer using multiphase CE-MRI, thereby providing a basis for selecting the optimal phase for GTV determination. Methods:Thirty patients with advanced pancreatic cancer [American Joint Committee on Cancer (AJCC) stage III-IV] who underwent magnetic resonance (MR) simulation were retrospectively enrolled in this study. MR T1-weighted images (T1WI) and contrast-enhanced T1-weighted images (CE-T1WI) were obtained at 15 s, 45 s, 75 s, 150 s, and >20 min after contrast injection. The GTV was determined from these different image sequences and named GTV-T1WI, GTV-15 s, GTV-45 s, GTV-75 s, GTV-150 s, and GTV-20 min. Differences in mean signal intensity (SI), SI contrast, volume, and shape among the different GTVs were compared. Normal pancreatic tissue was defined as a 1 cm3 region of interest of the parenchyma, strictly excluding blood vessels and pancreatic ducts. Results:The mean SI of the GTV was lower than that of the normal pancreatic tissue at each time phase (P<0.05), ranging from 9.93% to 45.01%. At CE-T1WI-15 s, the SI contrast between GTV and normal pancreatic tissue was the highest at 0.45±0.10, significantly superior to the T1WI (0.34±0.13, P<0.001). The GTV-15 s volume was 21.02±12.43 cm3. Compared with CE-T1WI-15 s, the SI contrast between the GTV and normal pancreatic tissue on T1WI and CE-T1WI-45 s to CE-T1WI-20 min decreased by 22.42-77.43% (P<0.05). Compared with GTV-15 s, the volume of GTV-T1WI and GTV-45 s-GTV-20 min decreased by -14.10-22.75%. Except for GTV-15 s and GTV-45 s, GTV-15 s and GTV-75 s, and GTV-45 s and GTV-75 s, the differences in GTV volumes in the other phases were statistically significant (P<0.05). The shape change trend of GTV at different phases was consistent with the volume compared with that of GTV-15 s. The Dice similarity coefficients (DSCs) of GTV-T1WI, GTV-45 s, GTV-75 s, GTV-150 s, and GTV-20 min were 0.74±0.10, 0.79±0.11, 0.76±0.13, 0.72±0.15, and 0.64±0.13, respectively. Conclusions:The CE-T1WI-15 s sequence demonstrated significant improvements in SI contrast and boundary definition. Consequently, it holds significant potential as an optimal sequence for GTV determination in pancreatic cancer radiotherapy, warranting further validation in larger cohorts.

Purpose: To compare the imaging manifestations of BM at 3-min and > 60-min delayed-enhanced MRI and explore their imaging characteristics and changing patterns in ultra-long delayed-enhanced MRI > 60 min. Methods: Twenty-six participants with BM were prospectively enrolled from May to October 2019. Contrast-enhanced (CE) T1-weighted imaging (T1WI) was performed for 3 min and > 60 min after contrast injection. BM were defined as regions of interest (ROI-3min and ROI-60min). The two ROIs were fused (ROI-total); the additional display area of the lesion at 3-min (ROI-A) and > 60-min (ROI-B) was determined. Signal intensity (SI), volume, and shape differences between ROIs and brain white matter were compared; the imaging characteristics of BM on ultra-long delayed-enhanced MRI were analyzed. Results: 12 males (age: 37–72 [median: 62] years) and 14 females (age: 41–79 [median: 61] years) were included. BM were divided into disappeared (n = 79, 38.0 %) and non-disappeared (n = 129, 62.0 %) groups. The average volume of the two groups at 3-min was 0.18 ± 0.25 and 3.53 ± 10.47 cm3 (p < .05). At > 60-min, BM in the non-disappeared group had four imaging manifestations: adduction (95.3 %), abduction (72.7 %), signal reversal (10.1 %), and filling (38 %) effects. In the non-disappeared group, ROI-3min, ROI-60min, ROI-total, ROI-A, and ROI-B volumes averaged 3.53 ± 10.47, 3.72 ± 11.51, 4.06 ± 11.76, 0.36 ± 0.54, and 0.54 ± 1.48 cm3 (p < .05). The DSC obtained from ROI-3min compared to ROI-60min was largest in the > 5 cm3 group. Conclusion: BM changed significantly in > 60-min delayed CE T1WI; no consistent regularity was observed.

AbstractThe study aimed to determine the specific relative biological effectiveness (RBE) of various cells in the hippocampus following proton irradiation. Sixty Sprague–Dawley rats were randomly allocated to 5 groups receiving 20 or 30 Gy of proton or photon irradiation. Pathomorphological neuronal damage in the hippocampus was assessed using Hematoxylin–eosin (HE) staining. The expression level of NeuN, Nestin, Caspase-3, Olig2, CD68 and CD45 were determined by immunohistochemistry (IHC). The RBE range established by comparing the effects of proton and photon irradiation at equivalent biological outcomes. Proton20Gy induced more severe damage to neurons than photon20Gy, but showed no difference compared to photon30Gy. The RBE of neuron was determined to be 1.65. Similarly, both proton20Gy and proton30Gy resulted in more inhibition of oligodendrocytes and activation of microglia in the hippocampal regions than photon20Gy and photon30Gy. However, the expression of Olig2 was higher and CD68 was lower in the proton20Gy group than in the photon30Gy group. The RBE of oligodendrocyte and microglia was estimated to be between 1.1 to 1.65. For neural stem cells (NSCs) and immune cells, there were no significant difference in the expression of Nestin and CD45 between proton and photon irradiation (both 20 and 30 Gy). Therefore, the RBE for NSCs and immune cell was determined to be 1.1. These findings highlight the varying RBE values of different cells in the hippocampus in vivo. Moreover, the actual RBE of the hippocampus may be higher than 1.1, suggesting that using as RBE value of 1.1 in clinical practice may underestimate the toxicities induced by proton radiation.

Abstract Background To establish and validate a predictive model combining pretreatment multiparametric MRI-based radiomic signatures and clinical characteristics for the risk evaluation of early rapid metastasis in nasopharyngeal carcinoma (NPC) patients. Methods The cutoff time was used to randomly assign 219 consecutive patients who underwent chemoradiation treatment to the training group (n = 154) or the validation group (n = 65). Pretreatment multiparametric magnetic resonance (MR) images of individuals with NPC were employed to extract 428 radiomic features. LASSO regression analysis was used to select radiomic features related to early rapid metastasis and develop the Rad-score. Blood indicators were collected within 1 week of pretreatment. To identify independent risk variables for early rapid metastasis, univariate and multivariate logistic regression analyses were employed. Finally, multivariate logistic regression analysis was applied to construct a radiomics and clinical prediction nomogram that integrated radiomic features and clinical and blood inflammatory predictors. Results The NLR, T classification and N classification were found to be independent risk indicators for early rapid metastasis by multivariate logistic regression analysis. Twelve features associated with early rapid metastasis were selected by LASSO regression analysis, and the Rad-score was calculated. The AUC of the Rad-score was 0.773. Finally, we constructed and validated a prediction model in combination with the NLR, T classification, N classification and Rad-score. The area under the curve (AUC) was 0.936 (95% confidence interval (95% CI): 0.901–0.971), and in the validation cohort, the AUC was 0.796 (95% CI: 0.686–0.905). Conclusions A predictive model that integrates the NLR, T classification, N classification and MR-based radiomics for distinguishing early rapid metastasis may serve as a clinical risk stratification tool for effectively guiding individual management.

Purpose This study seeks to examine the influence of the heartbeat on the position, volume, and shape of the heart and its substructures during various breathing states. The findings of this study will serve as a valuable reference for dose-volume evaluation of the heart and its substructures in radiotherapy for treating thoracic tumors. Methods Twenty-three healthy volunteers were enrolled in this study, and cine four-dimensional magnetic resonance images were acquired during periods of end-inspiration breath holding (EIBH), end-expiration breath holding (EEBH), and deep end-inspiration breath holding (DIBH). The MR images were used to delineate the heart and its substructures, including the heart, pericardium, left ventricle (LV), left ventricular myocardium, right ventricle (RV), right ventricular myocardium (RVM), ventricular septum (VS), atrial septum (AS), proximal and middle portions of the left anterior descending branch (pmLAD), and proximal portion of the left circumflex coronary branch (pLCX). The changes in each structure with heartbeat were compared among different respiratory states. Results Compared with EIBH, EEBH increased the volume of the heart and its substructures by 0.25–3.66%, while the average Dice similarity coefficient (DSC) increased by − 0.25 to 8.7%; however, the differences were not statistically significant. Conversely, the VS decreased by 0.89 mm in the left–right (LR) direction, and the displacement of the RV in the anterior–posterior (AP) direction significantly decreased by 0.76 mm ( p < 0.05). Compared with EIBH and EEBH, the average volume of the heart and its substructures decreased by 3.08–17.57% and 4.09–20.43%, respectively, during DIBH. Accordingly, statistically significant differences ( p < 0.05) were observed in the volume of the heart, pericardium, LV, RV, RVM, and AS. The average DSC increased by 0–37.04% and − 2.6 to 32.14%, respectively, with statistically significant differences ( p < 0.05) found in the right ventricular myocardium and interatrial septum. Furthermore, the displacements under DIBH decreased in the three directions (i.e.,− 1.73 to 3.47 mm and − 0.36 to 2.51 mm). In this regard, the AP displacement of the heart, LV, RV, RVM, LR direction, LV, RV, and AS showed statistically significant differences ( p < 0.05). The Hausdorff distance (HD) of the heart and its substructures under the three breathing states are all greater than 11 mm. Conclusion The variations in the displacement and shape alterations of the heart and its substructures during cardiac motion under various respiratory states are significant. When assessing the dose-volume index of the heart and its substructures during radiotherapy for thoracic tumors, it is essential to account for the combined impacts of cardiac motion and respiration.

BACKGROUND:This study aimed to construct and assess a comprehensive model that integrates MRI-derived deep learning radiomics, functional imaging (fMRI), and clinical indicators to predict early efficacy of radiotherapy in nasopharyngeal carcinoma (NPC). METHODS:This retrospective study recruited NPC patients with radiotherapy from two Chinese hospitals between October 2018 and July 2022, divided into a training set (hospital I, 194 cases), an internal validation set (hospital I, 82 cases), and an external validation set (hospital II, 40 cases). We extracted 3404 radiomic features and 2048 deep learning features from multi-sequence MRI includes T1WI, CE-T1WI, T2WI and T2WI/FS. Additionally, both the Apparent diffusion coefficient (ADC), its maximum (ADCmax) and Tumor blood flow (TBF), its maximum (TBFmax) were obtained by Diffusion-weighted imaging (DWI) and Arterial spin labeling (ASL) respectively. We used four classifiers (LR, XGBoost, SVM and KNN) and stacked algorithm as model construction methods. The area under the receiver operating characteristic curve (AUC) and decision curve analysis was used to assess models. RESULTS:The manual radiomics model based on XGBoost and the deep learning model based on KNN (the AUCs in the training set: 0.909, 0.823, respectively) showed better predictive efficacy than other machine learning algorithms. The stacked model that integrated MRI-based deep learning radiomics, fMRI, and hematological indicators, has the strongest efficacy prediction ability of AUC in the training set [0.984 (95%CI: 0.972-0.996)], the internal validation set [0.936 (95%CI: 0.885-0.987)], and the external validation set [0.959 (95%CI: 0.901-1.000)]. CONCLUSION:Our research has developed a clinical-radiomics integrated model based on MRI which can predict early radiotherapy response in NPC and provide guidance for personalized treatment.

Purpose This study aimed to demonstrate the feasibility and to evaluate the dosimetric effect and clinical impact of dose-painting proton radiotherapy (PRT) guided by functional MRI in non-enhancing high-grade gliomas (NE-HGGs). Material and methods The 3D-ASL and T2 FLAIR MR images of ten patients with NE-HGGs before radiotherapy were studied retrospectively. The hyperintensity on T2 FLAIR was used to generate the planning target volume (PTV), and the high-perfusion volume on 3D-ASL (PTV-ASL) was used to generate the simultaneous integrated boost (SIB) volume. Each patient received pencil beam scanning PRT and photon intensity-modulated radiotherapy (IMRT). There were five plans in each modality: (1) Uniform plans (IMRT60 vs. PRT60): 60Gy in 30 fractions to the PTV. (2)-(5) SIB plans (IMRT72, 84, 96, 108 vs. PRT72, 84, 96, 108): Uniform plan plus additional dose boost to PTV-ASL in 30 fractions to 72, 84, 96, 108 Gy. The dosimetric differences between various plans were compared. The clinical effects of target volume and organs at risk (OARs) were assessed using biological models for both tumor control probability (TCP) and normal tissue complication probability (NTCP). Results Compared with the IMRT plan, the D2 and D50 of the PRT plan with the same prescription dose increased by 1.27–4.12% and 0.64–2.01%, respectively; the R30 decreased by > 32%; the dose of brainstem and chiasma decreased by > 27% and >32%; and the dose of normal brain tissue (Br-PTV), optic nerves, eyeballs, lens, cochlea, spinal cord, and hippocampus decreased by > 50% (P < 0.05). The maximum necessary dose was 96GyE to achieve > 98% TCP for PRT, and it was 84Gy to achieve > 91% TCP for IMRT. The average NTCP of Br-PTV was 1.30% and 1.90% for PRT and IMRT at the maximum dose escalation, respectively. The NTCP values of the remaining OARs approached zero in all PRT plans. Conclusion The functional MRI-guided dose escalation using PRT is feasible while sparing the OARs constraints and demonstrates a potential clinical benefit by improving TCP with no or minimal increase in NCTP for tissues outside the PTV. This retrospective study suggested that the use of PRT-based SIB guided by functional MRI may represent a strategy to provide benefits for patients with NE-HGGs.

目的 研究应用MR三维动脉自旋标记(3D-ASL)成像在预测肺癌脑转移瘤(BMs)病理类型中的诊断价值.方法 回顾性分析237 例经病理证实为原发性肺癌BMs患者,均行头颅3.0TMR扫描成像,扫描序列包括增强T1WI、T2-FLAIR、ASL灌注图像,分别在BMs实性区、瘤周水肿区、对侧镜像区及正常脑白质区勾画感兴趣区域(ROIs)测量平均最大脑血流量(CBF),计算 BMs 实性区、瘤周水肿区相对脑血流量(rCBF)和灌注差值比(△CBF),并比较不同病理类型肺癌BMs在各定量参数的差异性及预测肺癌BMs病理类型的效能.结果 BMs腺癌组rCBF实性区平均值为1.70±0.61,较鳞癌组(1.44±0.44)及小细胞肺癌组(1.08±0.30)分别升高 18.1%、57.4%(P<0.05);△CBF实性区平均值为1.10±0.67,较鳞癌组(0.84±0.53)及小细胞肺癌组(0.43±0.48)分别升高30.9%、155.8%(P<0.05).BMs鳞癌组rCBF水肿区平均值为0.51±0.13,较腺癌组(0.58±0.15)及小细胞肺癌组(0.59±0.21)分别降低12.1%、13.6%(P<0.05);CBF水肿区平均值为17.68±3.45,较腺癌组(20.88±5.88)及小细胞肺癌组(23.17±5.61)分别降低 15.3%、23.7%(P<0.05).在鉴别小细胞肺癌与鳞癌、腺癌BMs诊断中,rCBF实性区的AUC值最高,为 0.828(0.774～0.883),最佳阈值为 1.185,敏感度为 72.1%,特异度为 82.3%.结论 3D-ASL可客观反映不同病理型肺癌BMs在肿瘤靶区、瘤周水肿区脑血流灌注情况.rCBF实性区、CBF水肿区、△CBF实性区参数有助于预测肺癌BMs病理分型.

The objective of this study is to analyse the diffusion rule of the contrast media in multi-phase delayed enhanced magnetic resonance (MR) T1 images using radiomics and to construct an automatic classification and segmentation model of brain metastases (BM) based on support vector machine (SVM) and Dpn-UNet. A total of 189 BM patients with 1047 metastases were enrolled. Contrast-enhanced MR images were obtained at 1, 3, 5, 10, 18, and 20 min following contrast medium injection. The tumour target volume was delineated, and the radiomics features were extracted and analysed. BM segmentation and classification models in the MR images with different enhancement phases were constructed using Dpn-UNet and SVM, and differences in the BM segmentation and classification models with different enhancement times were compared. (1) The signal intensity for BM decreased with time delay and peaked at 3 min. (2) Among the 144 optimal radiomics features, 22 showed strong correlation with time (highest R-value = 0.82), while 41 showed strong correlation with volume (highest R-value = 0.99). (3) The average dice similarity coefficients of both the training and test sets were the highest at 10 min for the automatic segmentation of BM, reaching 0.92 and 0.82, respectively. (4) The areas under the curve (AUCs) for the classification of BM pathology type applying single-phase MRI was the highest at 10 min, reaching 0.674. The AUC for the classification of BM by applying the six-phase image combination was the highest, reaching 0.9596, and improved by 42.3% compared with that by applying single-phase images at 10 min. The dynamic changes of contrast media diffusion in BM can be reflected by multi-phase delayed enhancement based on radiomics, which can more objectively reflect the pathological types and significantly improve the accuracy of BM segmentation and classification.

Background To research the pathological and clinical staging uses of arterial spin labeling (ASL) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Materials and methods 64 newly diagnosed nasopharyngeal carcinoma (NPC) patients were enrolled from December 2020 to January 2022, and 3.0 T MRI (Discovery 750W, GE Healthcare, USA) were used for ASL and DCE-MRI scans. The DCE-MRI and ASL raw data were processed post-acquisition on the GE image processing workstation (GE Healthcare, ADW 4.7, USA). The volume transfer constant (Ktrans), blood flow (BF), and accompanying pseudo-color images were generated automatically. Draw the region of interest (ROIs), and the Ktrans and BF values for each ROI were recorded separately. Based on pathological information and the most recent AJCC staging criteria, patients were divided into low T stage groups = T 1–2 and high T stage groups = T 3–4 , low N stage groups = N 0–1 and high N stage groups = N 2–3 , and low AJCC stage group = stage I–II and high AJCC stage group = stage III–IV. The association between the Ktrans t and BF parameters and the T, N, and AJCC stages was compared using an independent sample t-test. Using a receiver operating characteristic (ROC) curve, the sensitivity, specificity, and AUC of Ktrans t , BF t , and their combined use in T and AJCC staging of NPC were investigated and assessed. Result The tumor-BF (BF t ) (t = − 4.905, P < 0.001) and tumor-Ktrans (Ktrans t ) (t = − 3.113, P = 0.003) in the high T stage group were significantly higher than those in the low T stage group. The Ktrans t in the high N stage group was significantly higher than that in the low N stage group (t = − 2.071, P = 0.042). The BF t (t = − 3.949, P < 0.001) and Ktrans t (t = − 4.467, P < 0.001) in the high AJCC stage group were significantly higher than those in the low AJCC stage group. BF t was moderately positively correlated with the T stage (r = 0.529, P < 0.001) and AJCC stage (r = 0.445, P < 0.001). Ktrans t was moderately positively correlated with T staging (r = 0.368), N staging (r = 0.254), and AJCC staging (r = 0.411). There was also a positive correlation between BF and Ktrans in gross tumor volume (GTV) (r = 0.540, P < 0.001), parotid (r = 0.323, P < 0.009) and lateral pterygoid muscle (r = 0.445, P < 0.001). The sensitivity of the combined application of Ktrans t and BF t for AJCC staging increased from 76.5 and 78.4 to 86.3%, and the AUC value increased from 0.795 and 0.819 to 0.843, respectively. Conclusion Combining Ktrans and BF measures may make it possible to identify the clinical stages in NPC patients.

Objectives To quantify the pelvic bone marrow (PBM) fat content changes receiving different radiation doses of concurrent chemoradiotherapy for cervical cancer and to determine association with peripheral blood cell counts. Methods The data of 54 patients were prospectively collected. Patients underwent MRI iterative decomposition of water and fat with echo asymmetrical and least squares estimation (IDEAL IQ) scanning at RT-Pre, RT mid-point, RT end, and six months. The changes in proton density fat fraction (PDFF%) at 5–10 Gy, 10–15 Gy, 15–20 Gy, 20–30 Gy, 30–40 Gy, 40–50 Gy, and > 50 Gy doses were analyzed. Spearman’s rank correlations were performed between peripheral blood cell counts versus the differences in PDFF% at different dose gradients before and after treatment. Results The lymphocytes (ALC) nadirs appeared at the midpoint of radiotherapy, which was only 27.6% of RT-Pre; the white blood cells (WBC), neutrophils (ANC), and platelets (PLT) nadirs appeared at the end of radiotherapy which was 52.4%, 65.1%, and 69.3% of RT-Pre, respectively. At RT mid-point and RT-end, PDFF% increased by 46.8% and 58.5%, respectively. Six months after radiotherapy, PDFF% decreased by 4.71% under 5–30 Gy compared to RT-end, while it still increased by 55.95% compared to RT-Pre. There was a significant positive correlation between PDFF% and ANC nadirs at 5–10 Gy (r = 0.62, P = 0.006), and correlation was observed between PDFF% and ALC nadirs at 5–10 Gy (r = 0.554, P = 0.017). Conclusion MRI IDEAL IQ imaging is a non-invasive approach to evaluate and track the changes of PBM fat content with concurrent chemoradiotherapy for cervical cancer. The limitation of low-dose bone marrow irradiation volume in cervical cancer concurrent chemoradiotherapy should be paid more attention to.

Purpose: To study the effect of different enhancement timings of magnetic resonance (MR) on small-volume brain metastases (BM) visualisation and provide a basis for the contour of tumour targets. Method: We prospectively enrolled 101 patients with BM who received radiotherapy. All patients underwent computed tomography (CT) and MR simulations. Contrast-enhanced MR scans at 1, 3, 5, 10, 18, and 20 min after injection of contrast medium were performed. The tumour target was determined on MR images at different enhancement times, and the differences of tumour target volume, maximum diameter, and MR signal intensity were compared. Results: (1) Of the 453 metastatic lesions, 24 (5.2 %) were not detected at 1 min and 8 (1.8 %) were not detected at 3 min; however, all metastases were detected after 5 min. The volume and maximum diameter of the 28 (6.2 %) metastases were stable at any time. (2) The average volume of metastatic lesions at 1, 3, 5, 10, 18, and 20 min was 0.09 cm3, 0.10 cm3, 0.12 cm3, 0.12 cm3, 0.13 cm3, and 0.13 cm3, respectively. Compared to 1 min, BM volume at other times increased by 13.1 %, 21.5 %, 31.6 %, 39.6 %, and 41.7 %, and the difference between the maximum and minimum volumes was statistically significant (p < 0.05). (3) The distribution of the maximum ratio of tumours to white matter mean signal intensity at different times were 39.6 %, 20 %, 14.6 %, 8.0 %, 10.4 %, and 10 %, respectively. Conclusion: The visualisation of small-volume BM was significantly different at different enhancement times. Our results suggest that multi-timing enhancement scans for small-volume BM should be implemented and that scanning at >10 min is essential.

目的 应用动态增强磁共振成像(DCE-MRI)定量分析鼻咽癌调强放疗后肿瘤靶区、腮腺及翼外肌血流灌注变化,为鼻咽癌放疗疗效评估提供依据.方法 回顾性分析2020-12-21-2022-01-17山东省肿瘤医院确诊为鼻咽癌且接受放射治疗的17例患者.获取患者放疗前、中及结束时磁共振(MR)图像,包括T1加权成像(T1WI)、T2加权成像(T2WI)、T2加权脂肪抑制成像(T2 WI-FS)和DCE-MRI图像.在T2 WI-FS上勾画大体肿瘤靶区(GTV)、腮腺和翼外肌,获取不同区域DCE-MRI成像的Ktrans值.分析GTV、腮腺和翼外肌的体积和Ktrans变化规律及其相关性.结果 GTV体积在放疗中呈现持续减小趋势,放疗前、中、后体积分别为16.69(12.90,30.69)、7.80(6.25,15.06)和6.03(4.44,10.18)cm3,差异均有统计学意义,F=5.831,P后-前<0.001;F=2.915,P后-中=0.004;F=2.915,P中-前=0.004;腮腺体积在放疗中呈现持续减小趋势,放疗前、中、后体积分别为21.57(16.61,26.62)、14.61(12.00,20.78)和12.35(10.08,17.51)cm3,差异均有统计学意义,F=5.831,P后-前<0.001;F=2.915,P后-中=0.004;F=2.915,P中-前=0.004;翼外肌体积变化不大,放疗前、中、后体积分别为(8.07±2.35)、(7.83±2.25)和(7.36±2.29)cm3,差异无统计学意义,F=2.362,P=0.110.放疗中GTV Ktrans值呈下降趋势,放疗前、中、后Ktrans值分别为0.52(0.42,0.74)、0.37(0.30,0.45)和0.27(0.15,0.34)min-1,差异均有统计学意义,F=5.831,P后-前<0.001;F=2.915,P后-中=0.004;F=2.915,P中-前=0.004;放疗中腮腺Ktrans值变化呈持续升高趋势,放疗前、中、后Ktrans值分别为0.29(0.26,0.55)、0.49(0.33,0.81)和0.76(0.51,1.31)min-1,放疗前、后,放疗前、中差异有统计学意义,F=5.316,P后-前<0.001;F=3.430,P中-前=0.001,放疗中、后差异无统计学意义,F=1.886,P中-后>0.05;放疗中翼外肌Ktrans呈先升高后下降的趋势,整体呈升高趋势,放疗前、中、后Ktrans平均为(0.1±0.05)、(0.23±0.12)和(0.15±0.07)min-1,差异均有统计学意义,P后-前<0.001、P后-中=0.023、P中-前=0.001.GTV、腮腺、翼外肌放疗前、中、后体积和Ktrans的变化率之间均无相关性,均P>0.05.结论 鼻咽癌调强放疗中GTV、腮腺及翼外肌的体积与血流灌注变化呈不相关性,在疗效、损伤评估中应该引入血流灌注的生物学信息.

Abstract Objectives To quantify the dose-response relationship of changes in pelvic bone marrow (PBM) functional MR radiomic features (RF) during concurrent chemoradiotherapy (CCRT) for patients with cervical cancer and establish the correlation with hematologic toxicity to provide a basis for PBM sparing. Methods A total of 54 cervical cancer patients who received CCRT were studied retrospectively. Patients underwent MRI IDEAL IQ and T2 fat suppression (T2fs) scanning pre- and post-CCRT. The PBM RFs were extracted from each region of interest at dose gradients of 5–10 Gy, 10–15 Gy, 15–20 Gy, 20–30 Gy, 30–40 Gy, 40–50 Gy, and > 50 Gy, and changes in peripheral blood cell (PBC) counts during radiotherapy were assessed. The dose-response relationship of RF changes and their correlation with PBC changes were investigated. Results White blood cell, neutrophils (ANC) and lymphocyte counts during treatment were decreased by 49.4%, 41.4%, and 76.3%, respectively. Most firstorder features exhibited a significant dose-response relationship, particularly FatFrac IDEAL IQ, which had a maximum dose-response curve slope of 10.09, and WATER IDEAL IQ had a slope of − 7.93. The firstorder-Range in FAT IDEAL IQ and firstorder-10Percentile in T2fs, showed a significant correlation between the changes in ANC counts under the low dose gradient of 5–10 Gy (r = 0.744, -0.654, respectively, p < 0.05). Conclusion Functional MR radiomics can detect microscopic changes in PBM at various dose gradients and provide an objective reference for bone marrow sparing and dose limitation in cervical cancer CCRT.

Objective The present study aimed to evaluate the feasibility of sub-volume segmentation for radiotherapy planning of adult non-enhancing low-grade gliomas (NE-LGGs) guided by three-dimensional arterial spin labeling (3D-ASL). The differences in high- and low-perfusion areas of NE-LGGs were analyzed using multi-sequence magnetic resonance imaging (MRI) radiomics. Methods Fifteen adult patients with NE-LGGs were included in the study. MR images, including T1-weighted imaging (T1WI), T2 Propeller, T2 fluid-attenuated inversion recovery (T2 Flair), 3D-ASL, and contrast-enhanced T1WI (CE-T1WI), were obtained. The gross tumor volume (GTV) was delineated according to the hyperintensity on T2 Flair. The GTV was divided into high- and low-perfusion areas, namely GTV-ASL and GTV-SUB, respectively, based on the differences in cerebral blood flow (CBF) value. The volumes and CBF values of high- and low-perfusion areas were measured and compared. The least absolute shrinkage and selection operator (LASSO) regression was used to select the optimal features of all MR maps. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic accuracy of the absolute CBFmean (aCBFmean), relative CBFmean (rCBFmean, normalized by the CBF value of the normal gray matter), and screened features in differentiating high- and low-perfusion areas. Results Among the enrolled patients, three (20%) patients with NE-LGGs showed focal intra- and post-radiotherapy contrast enhancement within a prior high-perfusion area of 3D-ASL. The volume ratio of the GTV-ASL to the GTV was (37.08% ± 17.88)% (46.26 ± 44.51 vs. 167.46 ± 209.64 cm3, P = 0.000). The CBFmean in the high-perfusion area was approximately two times of that in the edema area or normal gray matter (66.98 ± 18.03 vs. 35.19 ± 7.75 or 33.92 ± 8.48 ml/100g/min, P = 0.000). Thirteen features were screened, seven of which were extracted from 3D-ASL. The area undercurve (AUC) values of aCBFmean, rCBFmean, and firstorder_10Percentile from 3D-ASL were more than 0.9, of which firstorder_10Percentile was the highest. Their cut-off values were 44.16 ml/100 g/min, 1.49 and 31, respectively. Conclusion The difference in blood perfusion in the GTV can be quantified and analyzed based on 3D-ASL images for NE-LGGs, which could guide the sub-volume segmentation of the GTV. 3D-ASL should become a routine method for NE-LGGs during simulation and radiotherapy.

Abstract Background: The purpose of this study was to investigate the feasibility and dosimetric characteristics of dose painting for non-enhancing low-grade gliomas (NE-LGGs) guided by three-dimensional arterial spin labeling (3D-ASL). Methods: Eighteen patients with NE-LGGs were enrolled. 3D-ASL, T2 fluid-attenuated inversion recovery (T2 Flair) and contrast-enhanced T1-weighted magnetic resonance images were obtained. The gross tumor volume (GTV) was delineated on the T2 Flair. The hyper-perfusion region of the GTV (GTV-ASL) was determined by 3D-ASL, and the GTV-SUB was obtained by subtracting the GTV-ASL from the GTV. The clinical target volume (CTV) was created by isotropically expanding the GTV by 1cm. The planning target volume (PTV), PTV-ASL were obtained by expanding the external margins of the CTV, GTV-ASL, respectively. PTV-SUB was generated by subtracting PTV-ASL from PTV. Three plans were generated for each patient: a conventional plan (plan1) without dose escalation delivering 95%-110% of 45-60Gy in 1.8–2Gy fractions to the PTV and two dose-painted plans (plan2 and plan3) with dose escalating by 10%-20% (range, 50-72Gy) to the PTV-ASL based on plan1. The plan3 was obtained from plan2 without the maximum dose constraint. The dosimetric differences among the three plans were compared. Results: The volume ratio of the PTV-ASL to the PTV was (23.49±11.94) % (Z=-3.724, P=0.000). Compared with plan 1, D2%, D98% and Dmean of PTV-ASL increased by 14.67%,16.17% and 14.31% in plan2 and 19.84%,15.52% and14.27% in plan3, respectively (P<0.05); the D2% of the PTV, PTV-SUB increased by 11.89% and 8.34% in plan2, 15.89% and 8.49% in plan3, respectively (P<0.05). The PTV coverages were comparable among the three plans (P>0.05). In plan2 and plan3, the conformity indexes decreased by 18.60% and 12.79%; while the homogeneity index increased by 1.43 and 2 times (P<0.05). Compared with plan1, the D0.1cc of brain stem and Dmax of optic chiasma were slightly increased in plan 2 and plan 3, and the absolute doses met the dose constraint. The doses of the other organs at risk (OARs) were similar among the three plans (P>0.05). Conclusions: The dose delivered to hyper-perfusion region derived from 3D-ASL can increased by 10-20% while respecting the constraints to the OAR, which provides a basis for future individualized and precise radiotherapy for NE-LGGs.

目的 分析基于CT/MR图像配准的脑转移瘤自适应放疗剂量累加的差异.方法 选取山东省肿瘤医院2018-11-07-2021-03-08接受放疗的33例脑转移瘤患者,初次和复位均行CT和MR模拟定位,制定自适应放疗计划,将2次计划基于CT和MR进行配准剂量累加,比较两者的差异.结果 初、复位基于MR确定的大体肿瘤靶区(GTV)较CT增加17％和27％(均P<0.05);危及器官(OAR)体积基本相当(均P>0.05);CT/MR确定的GTV初复位变化基本一致.GTV刚性配准的戴斯相似性系数(DSC)为0.673和0.688,全脑和局部形变配准的DSC为0.712、0.709和0.823、0.817.全脑与局部形变配准剂量累加的结果基本相当,形变配准与刚性配准相比,计划靶区(PTV)各指标变化率<2.9％;OAR的变化率<5.1％.基于MR的配准与CT比较,除Dmin、D98％和D99％变化较大外,其余变化率均<0.93％(均P>0.05);OAR变化率<7.0％(均P>0.05).结论 放疗过程中肿瘤靶区变化明显,自适应放疗为剂量评估提供一种可靠的方法.CT/MR肿瘤靶区的显示差异较大,MR图像配准较CT更具有优势,在脑转移瘤自适应放疗中MR图像应作为首选.