Objective:To investigate the dosimetric factors associated with acute nausea and vomiting (RINV) during intensity modulated radiotherapy for nasopharyngeal carcinoma.Methods:General clinical data and organs at risk (OAR) doses from 130 newly diagnosed early nasopharyngeal carcinoma patients who received radiation therapy alone in Henan Cancer Hospital from February 2018 to February 2023 were retrospectively analyzed. Dosimetric parameters were recorded, and the correlation between the parameters and the degree of nausea and vomiting was statistically analyzed using univariate and multivariate logistic regression models.Results:All 130 patients had symptoms of ≥ grade 1 nausea and vomiting. In the comparison of dosimetric parameters between patients with < grade 2 and ≥ grade 2 nausea, except the brainstem V 20 Gy, all parameters showed statistically significant differences (all P<0.05). The inner ear D max, and D max, D mean, V 10 Gy, V 20 Gy, V 30 Gy of the throat, oral cavity, pharyngeal constrictor, dorsal vagal complex (DVC) showed statistically significant differences between patients with grade 1 and grade 2 nausea (all P<0.05). The results of multivariate regression analysis showed that DVC V 30 Gy was a significant influencing factor in predicting the severity of nausea ( OR=73.95, 95% CI: 4.66-1172.60, P<0.001), and there was a significant correlation between oral V 30 Gy and the severity of vomiting ( OR=37.69, 95% CI: 1.26-1125.42, P=0.04). Conclusions:Even if OAR are exposed to lower doses of radiation, nausea or vomiting symptoms can still occur. The occurrence of RINV is significantly associated with DVC and oral radiation doses.

Objective:To investigate the status of personnel, facilities, and technology of radiation therapy in Henan province in 2023.Methods:A unified online survey questionnaire was designed and distributed from March to April 2023 by the Henan Cancer Diagnosis and Treatment Quality Control Center to various medical institutions throughout the province to investigate the personnel, radiotherapy equipment, quality control equipment, imaging equipment, and radiotherapy technology development of each radiotherapy unit. Descriptive statistical methods were mainly used.Results:As of April 30, 2023, there were a total of 168 units engaged in radiation therapy in Henan province. The number of physicians involved in radiation therapy was 956, along with 365 medical physicists and 680 technicians. The equipment inventory included 212 medical linear accelerators, 1 cobalt-60 therapy machine, 32 afterloading therapy apparatuses, 4 Cyber Knife, 173 CT simulators, 2 MRI simulators and 94 conventional simulators. Linear accelerators were the primary radiotherapy equipment, 2.15 units per 1 million population on average. Additionally, there were 11 units offering 2D radiotherapy, 24 units offering 3D conformal radiotherapy, 130 units offering intensity-modulated radiotherapy, 41 units offering rotational intensity-modulated radiotherapy, and 33 units offering stereotactic radiosurgery. Regarding physical quality control equipment, 16 units were equipped with three-dimensional water tanks, 162 units were equipped with radiation dose meters, 114 units were equipped with morning check meters, 60 units were equipped with film dose meters, and 108 units were equipped with intensity adjustment plan verification systems.Conclusions:In 2023, there is a shortage of radiation therapy professionals in Henan province. Disparities are observed in the distribution of radiation therapy equipment among regions. Intensity-modulated radiotherapy has become the mainstream technology for radiation therapy in Henan province. The configuration of radiation therapy quality control equipment and standardized quality control work should be further improved.

Objective:To investigate the accuracy of magnetic resonance imaging (MRI) cine sequences in determining the range of tumor motion in radiotherapy, providing a basis for the precise delineation of the target volume in motion for radiation therapy.Methods:A modified chest motion phantom was placed in a MRI scanner, and a water-filled sphere was used to simulate a tumor. True fast imaging with steady precession (TrueFISP) MRI cine sequences from Siemens were used to capture the two-dimensional motion images of the simulated tumor. The phantom experiments were divided into three modes: head-foot motion mode, rotation motion mode, and actual respiratory waveform mode. In the head-foot motion mode, respiratory motion period (3, 4, 5, 6, 7 and 8 s), amplitude (5, 10 and 15 mm), and respiratory waveform of the simulated tumor (sin and cos4) were set, resulting in a total of 36 motion combinations. In the rotation motion mode, a cos4 waveform was used for respiration, with respiratory periods of 3, 4, 5, 6, 7 and 8 s, head-foot motion set amplitudes of 5, 10 and 15 mm, and anterior-posterior (AP) and left-right (LR) motion set amplitudes in three combinations ([2.5, 2.5] mm, [2.5, 5.0] mm, [5.0, 5.0] mm), resulting in a total of 54 motion combinations. In the actual respiratory waveform mode, respiratory waveforms of 5 randomly selected patients from Affiliated Cancer Hospital of Zhengzhou University were obtained. Under each motion combination, TrueFISP cine images (30 frames, with an acquisition time of 11 s per frame) were obtained. The code was used to automatically identify the two-dimensional coordinates of the center of the simulated tumor in each image, and sin and cos4 functions were separately employed to fit the tumor position in the motion direction, thereby obtaining the fitted motion period and amplitude. The difference between the maximum and minimum values of the tumor's center coordinates in the head-to-foot direction is taken as the range of movement, referred to as the calculated amplitude. For the actual respiratory waveform, the distance between the measured maximum and minimum positions is used to calculate the amplitude.Results:In the head-foot motion mode, the fitted amplitudes of both sin and cos4 waveforms deviated from the set amplitudes by 0-0.51 mm, with relative deviations of 0%-4.2%. The deviation range between the calculated amplitudes and the set amplitudes of the two waveforms were 0.08-0.94 mm, with relative deviations of 1.1%-6.3%. In the rotation motion mode, the fitted amplitudes deviated from the set amplitudes by 0-0.61 mm, with relative deviations of 0%-6.2%. And the deviation range between the calculated amplitudes and the set amplitudes were 0.16-0.94 mm, with relative deviations of 0%-6.3%. In the actual respiratory waveform motion mode, the deviation range between the calculated amplitudes and the set amplitudes were 0.10-0.48 mm, with relative deviations of 2.2%-8.6%.Conclusion:TrueFISP cine sequences show minimal deviations in determining the range of tumor head-foot motion and effectively captures the tumor's movement state, thereby providing important support for the precise definition of the tumor movement target area during radiotherapy .

【Objective】 To compare the supply data of red blood cells(RBCs) from 18 blood centers in China before and after the outbreak of COVID-19 during 2018 to 2021. 【Methods】 Eight indicators related to RBCs supply from 18 blood centers in China during 2018-2021 were collected retrospectively, including the storage of total amount of qualified RBCs (referred to as the total amount of storage), the distribution of total amount of RBCs (referred to as the total amount of distribution), the distribution amount of RBCs per 1 000 population (referred to as the amount of distribution per 1 000 population), the distribution amount of RBCs from 400 mL original blood per 1 000 population [referred to as the amount of distribution per 1 000 population (400 mL)], the average daily distribution amount of RBCs (referred to as the average daily distribution amount), the average daily storage amount of RBCs (referred to as the average daily storage amount), the average storage days of RBCs when distribute (referred to as the RBC storage days), and the expired amount of RBCs (referred to as the expired amount). Based on the outbreak time of COVID-19, the data of 2018 and 2019 were the pre-pandemic group, and the data of 2020 and 2021 were the post-pandemic group. 【Results】 Data on RBCs supply in 18 blood centers from 2018 to 2021(comparison of the pre-pandemic group and the post-pandemic group): the amount of distribution per 1 000 population (median 14.68 U>13.92 U) decreased, the amount of distribution per 1 000 population (400 mL) (median 10.16 U>9.21 U) decreased, and the difference was statistically significant (P<0.05); data comparison between 2019 and 2020:the total amount of distribution (median 117 770.38 U>99 084.08 U) decreased, the amount of distribution per 1 000 population (median 15.04 U>12.19 U) decreased, the amount of distribution per 1000 population (400 mL) (median 10.11 U>8.94 U), the average daily distribution amount(322.66 U>270.73 U) decreased and RBC storage days (median 10.50 d<11.45 d) increased, the difference has statistical significance (P<0.05); data comparison between 2020 and 2021:the total amount of storage (median 101 920.25 U<120 328.63 U), the total amount of distribution (median 99 084.08 U<118 428.62 U), the amount of distribution per 1 000 population (median 12.19 U<15.00 U), the amount of distribution per 1 000 population (400 mL) (median 8.94 U<9.46 U), the average daily distribution amount (270.73 U>324.46 U), the average daily inventory (median 3 222.00 U<4 328.00 U) increased, the expired amount (median 1.50 U>0.00 U) decreased, the difference has statistical significance (P<0.05). The results of ANOVA showed that there were significant differences on the data related to RBCs supply (except expired amount) in different blood centers (P<0.05). The ratio of average daily stock to average daily distribution in the post-outbreak group (median 12.36 d) was higher than that in the pre-outbreak group (median 10.92 d), the difference has statistical significance (P<0.05), with significant difference among different blood centers (P <0.05). 【Conclusion】 The COVID-19 pandemic has a significant impact on RBCs supply in different blood centers. In the second year of the pandemic, the supply capability had recovered to some extent, and there were differences in RBCs supply in different blood centers.

Objective:To explore a new technique for lung dose reduction in esophageal cancer radiotherapy based on the dose distribution characteristics of the half-field combined with intensity-modulated radiotherapy (IMRT) technique.Methods:A three-dimensional water tank was used to measure the dose distribution at the edge of the symmetrical field and half-field, which was then compared and analyzed. Twenty patients with the middle and lower thoracic esophageal cancer receiving radiotherapy with prescription doses of 50.4-60.0 Gy were selected. Based on the Varian Vital beam linear accelerator and Eclipse planning system, flattening filter (FF) technique symmetrical field and half-field beam design and the flattening filter-free (FFF) technique symmetrical field and half-field design were adopted to compare and analyze various dose data and treatment MU numbers for the target area and the endangered organs. The field settings were chosen in the front 1 and back 4 mode.Results:Compared with the symmetrical field plan, the half-field plan significantly improved the irradiated dose to the lung with a statistically significant difference ( P<0.05), and the half-field FFF was slightly better than the half-field FF mode. Compared with the total lung V 5Gy, V 20Gy, V 30Gy, and D mean dosimetric parameters (Gy), the FF symmetric field and FFF half-field were (49.64±5.39)% vs.(42.70±5.53)%, (15.99±3.93)% vs.(13.32±3.06)%, (9.24±2.77)% vs.(8.50±2.62)%, and (10.45±1.76)% vs.(9.50±1.53)%, respectively. There was a significant reduction in the volume dose values for all structures of the lung (all P<0.05). For other comparative data, the irradiated dose for the heart of the symmetrical field was better than that of the half-field mode ( P<0.05), and the differences in conformity index (CI) and homogeneity index (HI), number of treated MU, and spinal cord associated with the target area were not statistically significant (all P>0.05). Conclusions:During radiotherapy for esophageal cancer, target area coverage and dose volume data of the lung are the main parameters affecting the efficacy and side effects. IMRT treatment based on the half-field mode can give full play to the advantages of half-field and IMRT, and significantly improve the irradiated dose to the lung, which can offer an additional clinical option.

Objective:In this paper, based on the 4D dose distribution of the treatment plan, the effects of respiratory movement on the dose distribution of three-dimensional conformal radiation therapy (3DCRT) and sliding window intensity-modulated radiation therapy (SW-IMRT) techniques were analyzed, and the dose errors caused by respiratory movement based on the 4D dose distribution were evaluated.Methods:In this study, the dynamic thoracic phantom (CIRS-008A) was used to simulate the patient with a 3 cm spherical insert as the tumor. Four motion patterns were simulated with cos 4( x) and sin ( x) wave forms of 10 mm and 5 mm amplitudes. The 4DCT scans with the phantom were performed in different breathing modes, and the maximum intensity projection (MIP), average intensity projection (AIP) and 10 separate 4DCT phase images were transferred to the Eclipse treatment planning system. The targets were contoured on MIP, with corresponding 3DCRT and SW-IMRT plans designed and dose calculated on AIP. By copying the plan designed on the AIP to each phase image of the 4DCT set, the MATLAB software package was employed to register and superimpose all the phase-specific doses onto one of the reference phase to create a 4D-accumulated dose distribution. Both films (EBT2) and optically stimulated luminescence (OSLD) detectors were inserted in and around the target area of the phantom to measure the delivered doses. The calculated 4D-accumulated doses were compared to the measured doses and their differences were evaluated using Gamma analysis. Results:Under different respiration modes, the average Gamma index (3%/3 mm) passing rates between the 4D-accumulated doses and EBT2-measured doses for 3DCRT and SW-IMRT plans were (98.8±0.78)% and (96.4±1.89)%, respectively. The absolute measurements of OSLDs both inside and outside of the target area well matched the 4D-accumulated doses.Conclusions:4DCT can be effectively applied to evaluate the treatment plan dose distribution through 4D dose accumulation, which can potentially avoid cold spots and target under-coverage. Under different respiration modes, both 3DCRT and SW-IMRT plans provide dose measurements consistent with those predicted by the 4D-accumulated dose of treatment plan.

Objective:To explore a new technology that can protect the lungs and heart better by utilizing the dose distribution attributes of the half-field and the characteristics of the VMAT (volumetric modulated arc therapy) technology.Methods:A three-dimensional water tank was used to measure the dose of symmetrical field and half field edge and analyze them comparatively. A total of 50 patients with left breast cancer receiving the postoperative radiotherapy were selected. Among them, 25 patients were performed conserving surgery and 25 patients were performed radical mastectomy. After the operation, all the patients received the prescription dose of 50 Gy in 25 fractions. Based on the Eclipse system, the symmetrical field continuous arc VMAT technology and the semi-field segmented arc VMAT technology were used to design the plan. Besides, the dose suitability data and the treatment efficiency of target areas and organs at risk were compared and analyzed.Results:The radiation size of half-field did not increase with the increased depth in the water mode. The symmetric field gradually enlarged due to the angle of tensor factor, increased to about 2 cm at the depth of 30 cm, and the delivery dose in the half-field was lower than that in the symmetric field. The closer the field edge is, the more obvious it is. Compared with the symmetric field continuous arc plan, the half-field segmental arc VMAT plan significantly improved the delivery dose of the lungs and heart ( t=-4.11, -4.42, P=0.00), in which the mean values of V5, V30, and Dmean for the whole structure of the heart were reduced by 52.5%, 65.5%, and 47%, respectively. The left anterior descending coronary artery, which was closely related to the target area, had a decrease of more than 20%. The mean values of V5, V10, V20, and Dmean of the affected lung were reduced by 21.6%, 24.8%, 25.0%, and 23.2%, respectively. The mean values of the doses of other endangered healthy organs, and the execution time of half-field segment arc plan were also better than the continuous arc plan. Conclusions:For breast cancer radiotherapy, the combination of half-field and VMAT can give full play to the advantages of half-field and VMAT, and significantly reduce the irradiated dose of the heart, affected lung, and healthy side of the breast.

Objective:To develop a verification platform based on Monte Carlo (MC) for independent dose verification of volumetric modulated arc therapy (VMAT) plans.Methods:The head model including collimator of Varian TrueBeam linear accelerator was constructed by using EGSnrc/BEAMnrc, and the independent dose verification platform for the patients’ VMAT plans was built based on the head model and an in-house code. The percent depth dose (PDD) curves and off-axis ratios for different field sizes, the dose distribution of two irregular fields and three VMAT plans of the head and neck, chest, and pelvis were simulated using the platform. The simulated results of the PDD curves and the off-axis ratios of different field sizes were compared with the blue water measurement results. The difference between the irregular fields and the actual ArcCHECK measurements was also investigated. Besides, the differences among the MC simulated dose, TPS calculated dose and the ArcCHECK measured dose were analyzed by several methods, such as γ analysis and dose-volume histogram to verify whether the platform could be independently employed for dose verification.Results:The MC simulated results of PDD curves and off-axis ratios from 4 cm×4 cm to 40 cm×40 cm were in good agreement with the measured results. And the γ passing rates between the MC simulation and the ArcCHECK measurement for the irregular fields were above 98.1% and 99.1% for 3%/2 mm and 3%/3 mm, respectively. For VMAT plans of three patients, the γ results between the MC simulated dose and ArcCHECK measured dose were better than 93.8% and 95.9% under the criteria of 3%/2 mm and 3%/3 mm respectively. At the same time, the γ passing rates of nasopharyngeal, lung, and rectal cancers were 95.2%, 98.6% and 98.9% based on 3D γ analysis using TPS calculated dose and MC simulated dose under the criteria of 3%/3 mm; the passing rates of these three were 90.3%, 95.1% and 96.7% for 3%/2 mm, respectively.Conclusions:The simulation results of the MC-based verification platform developed in this study show a good agreement with the actual measurement results, and the simulation results are closer to the real dose distribution using the patients’ data. The preliminary results demonstrate that the platform can be used for accurate independent dose verification of VMAT plans.

Objective: To compare relevant dosimetric parameters of non-coplanar volumetric modulated arc therapy (VMAT) in treating brain tumors in conventional flattening filter (FF) or flattening filter-free (FFF) delivery mode, aiming to explore the appropriate evaluation method of accelerator for stereotactic radiosurgery (SRS). Methods: Clinical data of 10 patients with single cranial tumor were retrospectively analyzed. All patients received non-coplanar VMAT at a prescription dose of 25 Gy in 1 fraction. Dosimetric parameters including conformity index (CI), heterogeneity index (HI), gradient index (GI₅₀, GI₂₅), gradient, volume of the brain tissue receiving larger than 10 Gy and 12 Gy(V₁₀ and V₁₂) and beam-on time were statistically compared between two treatment plans by paired sample t-test. Results: When FFF-VMAT was compared with FF-VMAT in SRS for intracranial tumors, Paddick gradient index GI₅₀ was 2.91±0.34 vs.3.07±0.35, 6.91±0.28 vs.7.35±0.27 for GI₂₅, (0.57±0.07) cm vs.(0.61±0.08) cm for gradient, respectively (all P<0.05), whereas CI did not significantly differ (P>0.05). For the normal brain tissues, the average dose was (160.64±43.64) cGy vs.(174.27±53.98) cGy, (45.35±30.32)% vs.(48.37±30.88)% for V₁₀ and (36.69±25.15)% vs.(39.48±25.37)% for V₁₂, respectively (all P<0.05). Conclusions Non-coplanar VMAT in FFF delivery mode can improve dose distribution and normal brain tissue sparing in the treatment of intracranial single tumors. Meanwhile, supplement of GI index and gradient index can implement comprehensive evaluation of the SRS planning.

Objective:To propose an automatic planning platform of the Raystation planning system suitable for multi-disease and multi-plan technique by using the Raystation built-in script function.Methods:IronPython and WPF user interface framework were utilized for programming and resolving the differences in the design of different types of plans for different diseases. The program was designed from prescription identification, visual plan parameter input and cost-function setting. The efficiency of automatic planning and manual planning was compared when applied in whole brain irradiation, nasopharyngeal carcinoma, cervical cancer, esophageal cancer and breast cancer, including IMRT and VMAT. The dosimetric parameters of the whole brain irradiation were chosen.Results:Physicists were only required to enter and select the necessary parameters to achieve the plan design by using the program. Compared with the five types of diseases, the maximum efficiency of automatic planning was 1.4 times higher than that of manual planning. In the dosimetric evaluation of the whole brain irradiation plan, both manual and automatic planning could meet the clinical needs, and the D 2%, CI and HI of the target area did not significantly differ (all P>0.05). The mean D 98% of the target area and the D max of lens in the manual plan were significantly higher than those in the automatic plan by 0.4% and 7.1%(both P<0.05). Conclusion:The developed program has the function of automatic planning system, which can realize the automatic planning of multi-disease and multi-type radiotherapy, significantly improve the efficiency of plan design and has important clinical application value.