Objective:Based on HyperArc stereotactic radiotherapy(SRT)technique,six-dimensional free bed combined with double mask fixation was used to treat intracranial tumors,and the positioning errors of within batch and between batches were analyzed,so as to provide basis for the accuracy of clinical treatment of this technique.Methods:A total of 13 patients with intracranial tumors who admitted to Peking Union Medical College Hospital from March to July 2023 were retrospectively selected,and they were treated by using HyperArc SRT technique.The validation images of cone-beam computed tomography(CBCT)of within batch and between batches during treatment were analyzed.The positioning errors of three translational direction[left and right(x),head and foot(y)and abdominal and dorsal(z)]and rotational direction were analyzed.The each positioning error was set as group A,and the remaining error after the positioning error was corrected through six-dimensional free bed was set as group B,and the error post treatment was set as group C.The difference between group B and group C was defined as the change of within batch.According to the margin formula,the positioning error of within batch was used to calculate the required range of margin.Results:Under the mode of six-dimensional free bed correction combined with double mask fixation,a total of 59 times of HyperArc SRT on head were performed.In the comparison of the average errors on the six-dimensional direction among groups A,B and C,the errors of group A on x direction and y direction were respectively(0.119±0.039)and(-0.133±0.047)cm,and the differences of them between group A and group B[(0.004±0.002)and(0.018±0.005)cm]were significant(t=2.890,-3.224,P<0.05).There were no significant differences on other directions between the two groups(P>0.05).The error of RX direction of group B was(0.033±0.021)°,and the difference of that between group B and group C[(0.122±0.045)°]was significant(t=-2.306,P<0.05),while there were no significant differences on other directions(P>0.05).In the margin of the design of the plan of intracranial tumors,the x,y and z directions were respectively 0.6,0.9 and 0.4 mm.Conclusion:In the radiotherapy of using HyperArc SRT technique for intracranial tumors,the use of six-dimensional free bed combined with double mask treatment can significantly shorten the margin,and ensure accurate irradiation for gross tumor volume(GTV)and simultaneously reduce the irradiation volume and dose of surrounding normal tissue.

Paraplegia caused by spinal cord injury is a serious neurological complication, for which surgery is currently the main treatment method. Due to different surgical approaches, patients are usually expected to maintain a passive prone position for a long time or switch between the supine and prone positions. Affected by multiple factors such as neurogenic sensory disorders, pathological changes in muscle tone and operative duration, the risk of intraoperative acquired pressure injury (IAPI) is significantly increased. Current clinical prevention strategies for IAPI in these patients predominantly focus on localized pressure relief during positioning, lacking systematic, standardized comprehensive prevention protocols or evidence-based guidelines. To address it, Department of Nursing, Orthopedics Branch, China International Exchange and Promotive Association for Medical and Health Care, Spinal Trauma Professional Committee, Orthopedics Branch, Chinese Medical Doctor Association, Nursing Group of Spine and Spinal Cord Professional Committee of Chinese Association of Rehabilitation Medicine organized experts in relevant fields to formulate Guideline for the prevention of intraoperative acquired pressure injury in paraplegic patients with spinal cord injury ( version 2025), based on evidence-based medical evidence and latest research results and clinical practice at home and abroad. Eleven recommendations were put forward from the aspects of preoperative risk assessment, intraoperative prevention strategies, postoperative handover and monitoring, and supportive mechanisms for IAPI prevention, aiming to standardize the prevention measures and management strategies of IAPI in paraplegic patients with spinal cord injury and accelerate the recovery of patients and improve the therapeutic effect.

Objective:To present a set of clinically representative quality assurance (QA) test cases for stereotactic radiosurgery (SRT) plans of multiple intracranial metastases, in order to assess the plan quality and machine execution capabilities.Methods:Based on the clinical characteristics of multiple brain metastases, four groups of test cases with three target volumes (TVs), six TVs, nine TVs, and TVs near organs at risk (OARs) were designed. For these cases, SRT plans were developed, and plan quality was assessed using metrics including the Radiation Therapy Oncology Group conformality index (RTOG CI), gradient index (GI), homogeneity index (HI), and the volume of normal brain tissue receiving a dose of 24 Gy ( V24 Gy), which was defined as the volume enclosed by the 24 Gy isodose line around the Brain-PTV ( V24 Gy of Brain-PTV). Verification plans were generated for each test case, including the verification of point doses, planar doses (PD), and SRS MapCHECK (SMC) semiconductor matrix planar doses. Compared with the calculated result of the treatment planning system (TPS), the criteria for the γ analysis of planar doses were set at 1 mm/2% and 2 mm/2%. Results:For the four groups of test cases, the mean CI, GI, HI, and V24 Gy of Brain-PTV were 1.04±0.03, 3.79±0.40, 0.73±0.01 and (7.46±3.80) cm 3, respectively. The mean deviations of the point doses were 0.88%±0.98%, 1.47%±0.79%, 1.52%± 0.76%, and 1.17% ± 0.38%, respectively. The mean γ passing rates of the single fields for PDs were greater than 98% at 2 mm/2% and exceeding 96% at 1 mm/2%, and the mean γ pass rates of the SMC semiconductor matrix for PDs were 97.75% ± 2.31% and 99.33% ± 0.62%, at 1 mm/2% and 2 mm/2% respectively. Conclusions:The proposed QA test cases for SRT of multiple intracranial metastases allow for the effective assessments of the plan quality and machine execution capabilities and, thus, can assist various centers in clinical applications.

Spectral computed tomography (CT) has triggered a technological revolution in radiodiagnosis while demonstrating its increasing application value in radiotherapy. Employing dual-energy techniques for material decomposition, spectral CT provides optimized solutions for several critical aspects of radiotherapy. Based on a review of the application situation of spectral CT in radiotherapy, this study delved into spectral CT′s significant advantages in image quality improvement, precise dose calculation, and comprehensive quantitative assessment. Furthermore, this study envisioned the development orientations and application prospects of spectral CT.

Objective:To establish daily quality assurance workflow based on self-developed phantom to ensure MR-linac performance such as beam accuracy, MR image guidance accuracy, and the clinical treatment workflow to enhance the efficiency of daily quality assurance (QA).Methods:The self-developed phantom was made by 3D printer and used in conjunction with Daily QA-MR detector array. After CT-sim scanning, a treatment plan was designed and transmitted to the accelerator, tests were performed such as image guidance accuracy, beam output and beam quality, the differences in daily QA results between the self-developed phantom and standard phantom recommended by the manufacturer were analyzed by using paired t-test. Results:A total of 24 sets results were collected, the image guide accuracy in the X, Y and Z directions between standard and self-made phantom were (0.1±0.4), (-0.14±0.16), (0.07±0.05) mm and (0±0.02), (-0.02±0.02), (0.02±0.01) mm, respectively, and the differences were statistically significant ( P<0.001, =0.001 and <0.001). Daily QA-MR detector array beam measurement results including output, symmetry, beam quality and field size were -0.11%±0.20%, -0.10%±0.19%, -0.01%±0.08%, (0.4±0.1) mm and (0.2±0.1) mm, respectively. The new process saved 25% (approximately 9 min) of the time compared to the standard process. Conclusions:The new daily QA process for MR-linac is performed based on self-developed phantom and Daily QA-MR detector array. The accuracy and sensitivity meet the requirements and can improve the QA efficiency.

support the diagnosis.The treatment of PHCC is mainly based on surgery.Due to the characteristics of intact capsule,surgical resection is relatively easy and the cure rate is higher than that of ordinary hepatocellular carcinoma,and the postoperative survival rate is relatively ideal.For unresectable PHCC,palliative treatment based on transcatheter arterial chemoembolization can be used.This article reviews the progress on diagnosis and treatment of PHCC in order to provide reference for clinical practice.

Objective:To present a set of clinically representative quality assurance (QA) test cases for stereotactic radiosurgery (SRT) plans of multiple intracranial metastases, in order to assess the plan quality and machine execution capabilities.Methods:Based on the clinical characteristics of multiple brain metastases, four groups of test cases with three target volumes (TVs), six TVs, nine TVs, and TVs near organs at risk (OARs) were designed. For these cases, SRT plans were developed, and plan quality was assessed using metrics including the Radiation Therapy Oncology Group conformality index (RTOG CI), gradient index (GI), homogeneity index (HI), and the volume of normal brain tissue receiving a dose of 24 Gy ( V24 Gy), which was defined as the volume enclosed by the 24 Gy isodose line around the Brain-PTV ( V24 Gy of Brain-PTV). Verification plans were generated for each test case, including the verification of point doses, planar doses (PD), and SRS MapCHECK (SMC) semiconductor matrix planar doses. Compared with the calculated result of the treatment planning system (TPS), the criteria for the γ analysis of planar doses were set at 1 mm/2% and 2 mm/2%. Results:For the four groups of test cases, the mean CI, GI, HI, and V24 Gy of Brain-PTV were 1.04±0.03, 3.79±0.40, 0.73±0.01 and (7.46±3.80) cm 3, respectively. The mean deviations of the point doses were 0.88%±0.98%, 1.47%±0.79%, 1.52%± 0.76%, and 1.17% ± 0.38%, respectively. The mean γ passing rates of the single fields for PDs were greater than 98% at 2 mm/2% and exceeding 96% at 1 mm/2%, and the mean γ pass rates of the SMC semiconductor matrix for PDs were 97.75% ± 2.31% and 99.33% ± 0.62%, at 1 mm/2% and 2 mm/2% respectively. Conclusions:The proposed QA test cases for SRT of multiple intracranial metastases allow for the effective assessments of the plan quality and machine execution capabilities and, thus, can assist various centers in clinical applications.

Spectral computed tomography (CT) has triggered a technological revolution in radiodiagnosis while demonstrating its increasing application value in radiotherapy. Employing dual-energy techniques for material decomposition, spectral CT provides optimized solutions for several critical aspects of radiotherapy. Based on a review of the application situation of spectral CT in radiotherapy, this study delved into spectral CT′s significant advantages in image quality improvement, precise dose calculation, and comprehensive quantitative assessment. Furthermore, this study envisioned the development orientations and application prospects of spectral CT.

Objective:Based on HyperArc stereotactic radiotherapy(SRT)technique,six-dimensional free bed combined with double mask fixation was used to treat intracranial tumors,and the positioning errors of within batch and between batches were analyzed,so as to provide basis for the accuracy of clinical treatment of this technique.Methods:A total of 13 patients with intracranial tumors who admitted to Peking Union Medical College Hospital from March to July 2023 were retrospectively selected,and they were treated by using HyperArc SRT technique.The validation images of cone-beam computed tomography(CBCT)of within batch and between batches during treatment were analyzed.The positioning errors of three translational direction[left and right(x),head and foot(y)and abdominal and dorsal(z)]and rotational direction were analyzed.The each positioning error was set as group A,and the remaining error after the positioning error was corrected through six-dimensional free bed was set as group B,and the error post treatment was set as group C.The difference between group B and group C was defined as the change of within batch.According to the margin formula,the positioning error of within batch was used to calculate the required range of margin.Results:Under the mode of six-dimensional free bed correction combined with double mask fixation,a total of 59 times of HyperArc SRT on head were performed.In the comparison of the average errors on the six-dimensional direction among groups A,B and C,the errors of group A on x direction and y direction were respectively(0.119±0.039)and(-0.133±0.047)cm,and the differences of them between group A and group B[(0.004±0.002)and(0.018±0.005)cm]were significant(t=2.890,-3.224,P<0.05).There were no significant differences on other directions between the two groups(P>0.05).The error of RX direction of group B was(0.033±0.021)°,and the difference of that between group B and group C[(0.122±0.045)°]was significant(t=-2.306,P<0.05),while there were no significant differences on other directions(P>0.05).In the margin of the design of the plan of intracranial tumors,the x,y and z directions were respectively 0.6,0.9 and 0.4 mm.Conclusion:In the radiotherapy of using HyperArc SRT technique for intracranial tumors,the use of six-dimensional free bed combined with double mask treatment can significantly shorten the margin,and ensure accurate irradiation for gross tumor volume(GTV)and simultaneously reduce the irradiation volume and dose of surrounding normal tissue.

support the diagnosis.The treatment of PHCC is mainly based on surgery.Due to the characteristics of intact capsule,surgical resection is relatively easy and the cure rate is higher than that of ordinary hepatocellular carcinoma,and the postoperative survival rate is relatively ideal.For unresectable PHCC,palliative treatment based on transcatheter arterial chemoembolization can be used.This article reviews the progress on diagnosis and treatment of PHCC in order to provide reference for clinical practice.