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Objective:To comprehensively evaluate the effects of different bolus usages in postmastectomy intensity-modulated radiotherapy (PM-IMRT) on doses.Methods:Fifty patients receiving PM-IMRT at Fudan University Shanghai Cancer Center from April to October 2021 were retrospectively studied. The planning target volume (PTV) was divided into four parts, namely chest wall (CW), internal mammary node, retained axillary lymph node, and supraclavicular node. The prescription dose was 50 Gy/25 fractions. Three PM-IMRT plans applying boluses with different thicknesses (3, 5 and 10 mm) were designed for each patient. The effects of different thicknesses and usage frequencies of boluses on PTV coverage, high dose volume of the CW skin, and dose to surrounding normal tissues were comprehensively evaluated.Results:When boluses were applied throughout the PM-IMRT, the PTV V95% of plans applying 10 mm-thick boluses was lower than that of plans applying 3 and 5 mm-thick boluses ( F=3.340, P < 0.05), the CI of plans applying 3 mm-thick boluses was higher than that of plans applying 5 and 10 mm-thick boluses ( F = 50.05, P < 0.05), and there was no statistically significant differences in the skin V105% and V110% of three plans( P > 0.05). Both PTV V95% and skin V105% were reduced with a decrease in the usage frequency of boluses. At a frequency of 20, PTV V95% decreased slightly (< 1%), while skin V105% decreased sharply to nearly half of the original values. At a frequency of 15, the PTV V95%, CI, and HI in the three plans showed no statistically significant dosimetric differences ( P > 0.05). The PTV Dmax of plans applying 3 mm-thick boluses was lower than that of plans applying 5 and 10 mm-thick boluses ( F = 9.21, P < 0.05). As for the dose to surrounding normal tissues, different bolus thicknesses and frequencies had negligible effects on doses to heart and lung, causing little different biological effects. Conclusions:For PM-IMRT, different bolus thicknesses have similar effects on doses to the PTV, skin, heart, and lung. Bolus usage frequency, rather than thickness, was the major factor determining the PTV coverage and the dose to CW skin.
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The purpose of this study is to establish and apply a correction method for titanium alloy implant in spinal IMRT plan, a corrected CT-density table was revised from normal CT-density table to include the density of titanium alloy implant. Dose distribution after and before correction were calculated and compared to evaluate the dose deviation. Plans were also copied to a spinal cancer simulation phantom. A titanium alloy fixation system for spine was implanted in this phantom. Plans were recalculated and compared with the measurement result. The result of this study shows that the max dose of spinal cord showed significant difference after correction, and the deviation between calculation results and measurement results was reduced after correction. The method for expanding the range CT-density table, which means that the density of titanium alloy was included, can reduce the error in calculation.
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Radioterapia de Intensidad Modulada/métodos , Titanio , Dosificación Radioterapéutica , Aleaciones , Radiometría/métodos , Planificación de la Radioterapia Asistida por Computador/métodosRESUMEN
Objective To explore the importance of head fixation in chest wall field combined with supraclavicular field radiotherapy for breast cancer by comparing the displacement error and dosimetric differences caused by multi-functional body board and breast bracket.Methods Thirty patients with breast cancer were randomly divided into groups A and B.In group A,patients were fixed with multi-functional body board and head thermoplastic film.In group B,patients were fixed with traditional breast brackets.Each patient received CBCT scan before and after radiotherapy.Both setup errors and intra-fractional displacements in the x-,y-and z-axis,V100 and V95 were calculated.Statistical analyses were performed using the independent sample t-test.Results The displacement errors in groups A and B before and after radiotherapy were (1.24± 0.42),(1.71± 0.61) and (2.25± 1.04) mm vs.(3.67± 2.05),(3.78± 1.74),(4.65±2.66) mm in the x-,y-and z-axis,respectively (P=0.033,0.027,0.020).The intra-fractional displacements in groups A and B were (1.10±0.66),(1.13±0.59),(1.11 ±0.62) mm vs.(2.48±0.88),(2.21 ±0.98),(3.53±2.01) mm in the x-,y-and z-axis,respectively (P=0.030,0.021,0.013).The V100 in groups A and B were (94.27± 3.20) ％ and (99.08± 0.60) ％ (P =0.065),and (89.48± 4.70) ％ and (96.53± 2.50) ％ for V95 (P =0.002),respectively.Conclusion The risk of displacement error is significantly reduced using multi-functional body board,which enhances the accuracy of radiation dose in chest wall and supraclavicular fields of breast cancer patients.
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Objective To retrospectively review the history and development of radiotherapy quality assurance ( QA) in the Affiliated Cancer Hospital of Fudan University, and to report the primary experience and evolvement of an entire QA workflow management. Methods The multidisciplinary QA team has implemented an entire QA workflow management process in the Radiotherapy Center using the failure modes and effects analysis ( FMEA) and plan?do?check?act ( PDCA) tool since April 2015. Treatment data of approximately 6000 patients before and after implementation were compared. Results The error rate was reduced from 17% to 09% after using the entire QA workflow management. Conclusions Entire QA workflow management effectively improves the accuracy and safety of radiotherapy.
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Objective To develop a practical image acquisition strategy using intermittent breath?hold cone beam computed tomography (CBCT). Methods A breathing phantom was used to simulate the movement of tumor near the diaphragm during free breathing and breath hold and scanned by conventional breath?hold CBCT and type Ⅰ/Ⅱ intermittent breath?hold CBCT. In the conventional breath?hold CBCT, scan paused and free breathing occurred at the break of breath hold and free breathing was not included in the scan. In the intermittent breath?hold CBCT, one scan covered several breath holds separated by free breathing in a ratio of 3 vs1. Image quality and three?dimensional registration accuracy were quantitatively compared between conventional breath?hold CBCT and type Ⅰ/Ⅱ intermittent breath?hold CBCT. Comparison of image quality parameters between conventional breath?hold CBCT and intermittent breath?hold CBCT was made by paired t test. Results Motion artifacts arose in type I and Ⅱ intermittent breath?hold CBCT scans. There were no significant differences in the reconstructed pixel value or uniformity between intermittent breath?hold CBCT and conventional breath?hold CBCT ( P>0. 05, and P= 0. 02, 0. 53 ) . Compared with conventional breath?hold CBCT images, the signal?to?noise ratios of type I andⅡintermittent breath?hold CBCT images were reduced by 30% and 60%, respectively ( P<0. 05 ) . The registration error was up to 0 . 4 cm in the anterior?posterior direction and less than 0 . 1 cm in other directions . Conclusions The phantom study shows that intermittent breath?hold CBCT does not significantly reduce image quality or registration accuracy compared with conventional breath?hold CBCT. The feasibility of intermittent breath?hold CBCT in clinical application needs to be further validated among a large number of patients.
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Objective To investigate the change in body weight over time in rectal cancer patients receiving radiotherapy and the correlation between setup errors and weight loss,and to establish the image-guided radiotherapy regimens in different periods of treatment.Methods A total of 24 postoperative patients with rectal cancer admitted to our hospital in 2016 were selected.Before each fraction of radiotherapy,the body weight was recorded,and the patients underwent cone-beam computed tomography (CBCT) with different frequencies in every week.The planning CT was matched with CBCT to obtain setup errors.The paired t test was used for difference analysis;the Pearson method was used to analyze the correlation between setup errors and weight loss.Results Body weight was measured 456 times in the 24 patients,and these patients underwent CBCT scans and image registration 456 times.Two patients were excluded because of treatment discontinuance.In the first and second weeks,there was no significant change in body weight.In the third week,the mean weight loss was 1.53 kg.In the fourth week,the mean weight loss was 2.48 kg.In the fifth week,the mean weight loss was 3.24 kg.The setup errors obtained by CBCT image registration in the superior-inferior (SI),anterior-posterior (AP),and left-right (LR) directions were 0.19 cm,0.20 cm,and 0.18 cm,respectively,in the first week,0.18 cm,0.17 cm,and 0.15 cm,respectively,in the second week,0.20 cm,0.22 cm,and 0.21 cm,respectively,in the third week,0.19 cm,0.25 cm,0.24 cm,respectively,in the fourth week,and 0.34 cm,0.33 cm,and 0.31 cm,respectively,in the fifth week.The Pearson correlation analysis showed that weight loss increased the setup errors,with P values of 0.140,0.046,and 0.044 in the SI,AP,and LR directions,respectively.Conclusions For rectal cancer patients receiving radiotherapy,the body weight decreases significantly in the late period (especially in the fifth week),which influences the setup errors.Therefore,in the fourth and fifth weeks of radiotherapy for rectal cancer,the weight loss should be closely monitored,and the number of CBCT scans can be increased before the treatment fraction to ensure the accuracy and optimization of treatment.
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Background and purpose: Radiation therapy has entered the era of precise radiotherapy. Set-up error becomes important factor affecting the effects of radiotherapy. The aim of this study was to analyze the set-up accuracy of the in-house developed technique of body plate with vacuum cushion and thermoplastic mask (Group A) and the conventional technique of arm support (Group B) in thoracic tumor radiotherapy. Methods: A total of 19 patients with thoracic tumor were enrolled in this study and randomly separated into Group A and Group B. The patients of Group A underwent the secondary set-up: align the marker on vacuum cushion and patient's body to the room laser, cover the patient's body with thermoplastic mask and align the marker on the mask to the room laser. The patients of Group B were directly setup by aligning the marker on the patient's body to the room laser. The kilo-voltage cone beam computed tomography (KV-CBCT) was performed on each patient to collect the pre- and post-treatment CBCT images. The CBCT images were registered to the planning CT to analyze the translational error of Group A and Group B. Results: The pre-treatment set-up errors of Group A vs Group B were (1.06±0.58) vs (1.82±0.82) mm in left and right (LR) direction, (1.31±0.40) vs (2.18±1.20) mm in superior and inferior (SI) direction, and (1.28±0.66) vs (2.94±1.81) mm in anterior and posterior (AP) direction. The post-treatment set-up errors of Group A vs Group B were (0.86±0.54) vs (1.29±0.58) mm in LR direction, (1.07±0.58) vs (1.08±0.45) mm in SI direction, and (0.98±0.53) vs (1.56±0.63) mm in AP direction.Conclusion: The in-house developed immobilization technique of body plate with vacuum cushion and thermoplastic mask was more accurate and reproducible than the conventional immobilization technique of arm support in thoracic tumor radiotherapy.
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Objective To investigate the effects of high-fat diet on the formation of colorectal adenomas in rats.Methods Twenty Wistar rats were evenly divided into two groups,one group were fed with common food and the other group were fed with high fat-diet.The rats of two groups were intraperitoneally injected with 1,2-dimethyl-hydrazine (DMH) (40 mg/kg) once a week for 10 consecutive weeks.Rats with common diet and DMH were assigned to SDT group,and those with high-fat diet and DMH were assigned to HFDT group.The expression of Ki-67 was detected by immunohistochemistry and the expression of proliferating cell nuclear antigen (PCNA) and cyclooxy-genase 2 (COX2) was detected by immunofluorescence.The levels of serum triglyceride,cholesterol,insulin like growth factor-1 (IGF-1),insulin,leptin and tumor necrosis factor-α were determined by enzyme linked immunosorbent assay.Student's t test and Mann-Whitney test were performed for statistical analysis.Results At the 18th week,the numbers of Ki-67 positive cells of SDT group and HFDT group were 24.00± 1.84 and 75.17 ± 3.17,respectively,and the difference was statistically significant (t=13.960,P＜0.01).The fluorescence intensity of PCNA of SDT group and HFDT group was 213.70±21.61 and 333.30±30.44,respectively,and the difference was statistically significant (t =4.987,P＜0.01).The levels of serum triglyceride of SDT group and HFDT group were (0.43 ± 0.05) mmol/L and (1.14±0.07) mmol/L,respectively,and the difference was statistically significant (t=8.366,P＜0.01).The levels of cholesterol were (3.75±0.'26) pmol/L and (7.77±0.79) pmol/L,respectively,and the difference was statistically significant (t=4.851,P＜0.01).Conclusion High-fat diet can promote the genesis and development of adnomas through influencing the body's endocrine metabolism,increasing cell proliferation cycle and regulating inflammatory reaction.
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Objective To clarify the anatomical and pathlogical implications of Denonvilliers' fascia.Method In this study,thirty pelvic specimens (17 males and 13 females) were incised through the median sagittal plane and carried for regional anatomy study; Denonvilliers' fascia was identified by immunohistochemistry.Results Denonvilliers' fascia could be found in all male specimens:it had an anterior leaf and a posterior leaf,with the anterior one attaching to seminal vesicle,seminiferous duct,prostate and the bottom of bladder firmly.The fascia originated at the fold of the peritoneum and ended at the perineum fascia,fusing into the pelvic parietal fascia laterally.It was not obvious in females,only to find a thin and transparent membrane between vagina and rectum.The maximum height of Denonvilliers' fascia in left pelvis was (3.2 ± 0.3) cm,compared with (3.3 ± 0.3) cm in the right pelvis (t =0.965,P ＞ 0.05).Immunohistochemistry study revealed that there was no lymph node in the fascia and its lateral parts were enriched of nerve fibers,which were few in its middle part.Conclusions The unique anatomical and pathlogical characteristics of Denonvilliers' fascia are of vital importance to the avoidance of nerve injury during rectal surgery.
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As a crucial part of the DNA damage repair process,the expression of excision repair cross-complementing group 1 (ERCC1 )is closely related to the genesis and development of gastric cancer.Studies find that ERCC1 gene polymorphism can alter the expression of the gene itself,which affects the sensitivity and efficacy of platinum-based chemotherapy.Therefore,the detection of ERCC1 polymorphism may guide the indi-vidualized chemotherapy of the patients with gastric cancer.
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Zinc-finger protein X-linked is a member of zinc finger protein family.Its abnormal expression has been found in a variety of stem cells and malignant tumor cells.Recent studies have shown that it plays an important role in stem cell self-renewal and cancer cell proliferation,apoptosis and migration.
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Objective To investigate a new automatic inverse optimal solution based on VMAT optimization model and verify its result.Methods A variant of the new automatic inverse optimal solution was proposed in this study,which provided a solution to calculate treatment plan with the minimized number of beams and the minimized levels of their intensities on the basis of VMAT optimization model by customized software tools.The verifications were evaluated on the simulated head-neck phantom by dosimetric parameters.Results Compared with conventional IMRT/VMAT treatment plans,the adaptive optimization program(AOP)plan showed that plan20/40(20 fields with totally 40 sub-fields,m=2)made the best achievement and it was clinicable.Conclusions The proposed new optimization technique provides an effective way to reach an inverse treatment plan with the best compromise and less sub-fields compared with IMRT/VMAT plans.
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Objective To quantitatively evaluate the image quality, stability and volume precision in kilovoltage cone beam CT (CBCT) on Varian linear accelerator. Methods The Catphan (R) 600 phantom was repeatedly scanned in the full-fan and half-fan CBCT scanning modes. A simulation fan-beam CT (FBCT) was used as a benchmark and results related to the low contrast resolution, spatial resolution,uniformity and image noise were compared with the CBCT using the treatment planning system. The comparison of image quality and long-term stability and volume precision was analyzed. Results Spatial resolution was no differences observed between FBCT and CBCT ( 6 lp/cm: 6 lp/cm , T = 18. 00 , P＞ 0. 05 ) .Low contrast resolution was, on average, 1. 65％ and 1. 74％ for both CBCTFull-Fan and CBCTHalf-Fan , and 1. 03％ for the FBCT ( T =6. 00, P ＜ 0. 05). Uniformity was, on average, 0. 005 and 0. 033 for both, and 0. 003 for the FBCT ( T=6. 00 , P ＜0. 05). In terms of image noise, the FBCT images were superior to the CBCT (T=30. 00, P＜O. 05). In valid scan range of the CBCT, reconstructed precision was high. There was no significant time trend in the image quality. Conclusions The image quality of kilovoltage CBCT is inferior to the conventional CT. However, tumor and soft tissues are visible in the CBCT images. The image stability and reconstructed precision is satisfying.
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ObjectiveTo determine the prevalence of nutritional risk and application of nutrition support in hospitalized patients in the department of general surgey,and to evaluate the relationship between nutrition support and clinical outcome as well as between nutritional risk and clinical outcome.MethodsHospitalized patients in the department of general surgery were enrolled from September 2009 to April 2010.The patients were screened using Nutritional Risk Screening 2002 ( NRS 2002) on admission.Data were collected on the application of nutrition support within 2 weeks,complication rate,length of stay,and hospital charges.ResultsAltogether 3000 patients were included in the present study.The overall prevalence of nutritional risk was 18.5％,in which gastric cancer patients showed the highest prevalence (48.3％ ).The proportion of patients receiving nutrition support was 44.1％ in those with nutritional risk and 14.3％ in those without nutritional risk.The ratio of parenteral nutrition to enteral nutrition was 1.2:1.The patients with nutritional risk had higher complication rate,longer length of stay,and higher hospital charge [24.1％ vs.14.2％,(11.1 ±4.8) daysvs.(9.6±3.7) days,(12891.5±4831.2) yuan vs.(9982.7 ±3996.4) yuan,all P=0.0000].Among the gastric cancer,colorectal cancer,and hepato-biliopancreatic cancer patients with nutritional risk,the complication rate,length of stay,and hospital charge were significantly lower in the patients receiving nutrition support than those in the patients receiving no nutrition support ( all P ＜ 0.05 ).ConclusionsA number of inpatients in general surgery department are at nutritional risk.The prevalence of nutritional risk is considerably high in gastric cancer patients.Nutritional risk is correlated with the clinical outcome of the patients.Nutrition support may improve the clinical outcome of gastric cancer,colorectal cancer,and hepato-bilio-pancreatic cancer patients.