Objective To discuss the effect of different particle activities and tumor shrinkage speed on the dosimetric parameters of the target area at the same prescription dose after 125I particle implantation.Methods A 6cm-sized cube tumor model was outlined by using a computerized three-dimensional treatment planning system(3D-TPS)with a prescription dose(PD)of 100 Gy,and 125I particle activities of 0.4 mCi and 0.8 mCi were selected.Assuming that the tumor shrinks centripetally after seed implantation and that the 125I particles were uniformly and centripetally concentrated without shedding or wandering,the tumor volume shrank at different rates every month after implantation(0,5％,10％,15％,20％,25％,30％,35％,40％,45％and 50％),according to the different activities of 125I particles,the experiments were divided into A1-K1 group(0.4 mCi)and A2-K2 group(0.8 mCi).Based on the 125I particle decay law,the validation program(using TPS simulation of the A1-K1 group and A2-K2 group at postoperative 1,2,3,4,5 and 6 months)obtained the dose received by 90％of the target volume(D90)in the two groups with different 125I particle activities at different postoperative time points,the percentages of the target volume covered by the 100％,150％and 90％prescription dose(V100,V150,V90),and the mean dose(Dmean).By comparing the differences in D90,V100,V150,V90 and Dmean after tumor implantation of 125I particles with different activities,the dosimetric impact of the tumor target area shrinking at a rate of 0～50％after implantation of 125I particles with different activities into tumor tissues was analyzed.Results When the monthly shrinkage rate of the tumor target area was≤30％,there was no obvious difference in D90 between the 0.4 mCi group and 0.8 mCi group in 1～6 months after surgery.When the monthly shrinkage rate of the tumor target area was＞30％,the D90 of 0.8 mCi group was higher than that of 0.4 mCi group;when the monthly shrinkage rate of the tumor target area was＜25％,the V90 of 0.4 mCi group was higher than that of 0.8 mCi group,and the changes of V90 of the two groups tended to be the same in the 5th～6th month after surgery.When the monthly shrinkage rate of the tumor target area was ≥30％,the V90 of 0.8 mCi group was higher than that of 0.4 mCi group,and with the increasing of shrinkage rate,the difference between the two groups become more and more significant,the results of V100 were consistent with those of V90.When the monthly shrinkage rate of tumor target area＜35％,V150 of 0.4 mCi group was higher than that of 0.8 mCi group,when the monthly shrinkage rate of tumor target area ≥35％,V150 of 0.8 mCi group was higher than that of 0.4 mCi group,and with the increasing of shrinkage rate,the difference between the two groups become more and more prominent.When the monthly shrinkage rate of tumor target area＜25％,Dmean of 0.4 mCi group was higher than that of 0.8 mCi group,when the monthly shrinkage rate of tumor target area ≥25％,Dmean of 0.8 mCi group was higher than that of 0.4 mCi group,and with the increasing of shrinkage rate,the difference between the two groups become more and more obvious.Conclusion With the same prescription dose,when the tumor target area shrinks at a rate of＜30％per month,the activity of 125I particles has little effect on D90,and all V90,V100,V150 and Dmean in the low activity group are higher than those in the high activity group,meanwhile the homogeneity of the target area is relatively good;when the monthly shrinkage rate of tumor target area ≥35％,all D90,V90,V100,V150 and Dmean in the high activity group are higher than those in the low activity group,and the duration of the presence of high-dose area is long.This difference becomes more obvious with the increasing of the monthly shrinkage rate of the target area.

Objective:To explore the correlation between quantitative parameters based on SUV acquired by dynamic SPECT/CT imaging of parotid glands and pathological grading of labial gland in patients with primary Sj?gren syndrome (pSS).Methods:Seventy-two patients (6 males, 66 females, age (51.5±13.8) years) with confirmed pSS diagnosed at Hebei General Hospital between August 2022 and March 2024 were prospectively included. The clinical data and pathological grading information from labial gland biopsies were analyzed. Dynamic SPECT/CT imaging of the parotid glands was performed, and quantitative parameters based on SUV were obtained using Q-metrix software: SUV max, SUV mean, uptake volume of parotid glands (UVP) and total parotid uptake (TPU) pre/post-acid stimulation, as well as the differences in quantitative parameters before and after acid stimulation (ΔSUV max, ΔSUV mean, ΔUVP, and ΔTPU). The independent-sample t test or Mann-Whitney U test was performed to evaluate the differences in parameters between patients with pathological grade 1-2 and those with pathological grade 3-4. Spearman rank correlation was used to analyze the correlation between quantitative parameters and pathological grading. The performance of quantitative parameters in distinguishing pathological grade 1-2 from grade 3-4 was assessed using ROC curve analysis with Delong test. Results:The SUV max pre/post-acid stimulation in patients with pathological grade 1-2 ( n=30) were higher than those in patients with grade 3-4 ( n=42) (36.38(27.81, 44.17) vs 15.45(10.77, 24.51), Z=-5.51, P<0.001(pre-acid stimulation); 21.53(16.93, 26.21) vs 11.33(7.32, 15.89), Z=-5.27, P<0.001 (post-acid stimulation)). SUV mean, UVP and TPU pre/post-acid stimulation in patients with pathological grade 1-2, as well as ΔSUV max, ΔSUV mean and ΔTPU, were all significantly higher ( Z values: from -4.73 to -3.04, t values: 6.39, 4.50, all P<0.01). Moreover, these parameters were negatively correlated with the pathological grading ( rs values: from -0.66 to -0.36, all P<0.05). No significant difference in ΔUVP was observed between patients with pathological grade 1-2 and those with grade 3-4 ( Z=-1.05, P=0.293), and ΔUVP showed no correlation with pathological grading ( rs=-0.13, P=0.297). Among all parameters, SUV max pre/post-acid stimulation and TPU pre-acid stimulation exhibited better diagnostic performance in differentiating pathological grade 1-2 from grade 3-4, with AUC values of 0.883, 0.866, and 0.888, respectively. Delong test showed that those 3 AUC values were all higher than AUC values of SUV mean, UVP post-acid stimulation and ΔUVP (all AUC<0.800; Z values: 2.09-4.65, all P<0.05). Conclusion:The quantitative parameters of parotid glands based on SUV acquired by dynamic SPECT/CT can reflect the damage degree of parotid glands in patients with pSS, providing novel quantitative analytical tools for the functional diagnosis and assessment of pSS.

Objective:To explore the correlation between quantitative parameters based on SUV acquired by dynamic SPECT/CT imaging of parotid glands and pathological grading of labial gland in patients with primary Sj?gren syndrome (pSS).Methods:Seventy-two patients (6 males, 66 females, age (51.5±13.8) years) with confirmed pSS diagnosed at Hebei General Hospital between August 2022 and March 2024 were prospectively included. The clinical data and pathological grading information from labial gland biopsies were analyzed. Dynamic SPECT/CT imaging of the parotid glands was performed, and quantitative parameters based on SUV were obtained using Q-metrix software: SUV max, SUV mean, uptake volume of parotid glands (UVP) and total parotid uptake (TPU) pre/post-acid stimulation, as well as the differences in quantitative parameters before and after acid stimulation (ΔSUV max, ΔSUV mean, ΔUVP, and ΔTPU). The independent-sample t test or Mann-Whitney U test was performed to evaluate the differences in parameters between patients with pathological grade 1-2 and those with pathological grade 3-4. Spearman rank correlation was used to analyze the correlation between quantitative parameters and pathological grading. The performance of quantitative parameters in distinguishing pathological grade 1-2 from grade 3-4 was assessed using ROC curve analysis with Delong test. Results:The SUV max pre/post-acid stimulation in patients with pathological grade 1-2 ( n=30) were higher than those in patients with grade 3-4 ( n=42) (36.38(27.81, 44.17) vs 15.45(10.77, 24.51), Z=-5.51, P<0.001(pre-acid stimulation); 21.53(16.93, 26.21) vs 11.33(7.32, 15.89), Z=-5.27, P<0.001 (post-acid stimulation)). SUV mean, UVP and TPU pre/post-acid stimulation in patients with pathological grade 1-2, as well as ΔSUV max, ΔSUV mean and ΔTPU, were all significantly higher ( Z values: from -4.73 to -3.04, t values: 6.39, 4.50, all P<0.01). Moreover, these parameters were negatively correlated with the pathological grading ( rs values: from -0.66 to -0.36, all P<0.05). No significant difference in ΔUVP was observed between patients with pathological grade 1-2 and those with grade 3-4 ( Z=-1.05, P=0.293), and ΔUVP showed no correlation with pathological grading ( rs=-0.13, P=0.297). Among all parameters, SUV max pre/post-acid stimulation and TPU pre-acid stimulation exhibited better diagnostic performance in differentiating pathological grade 1-2 from grade 3-4, with AUC values of 0.883, 0.866, and 0.888, respectively. Delong test showed that those 3 AUC values were all higher than AUC values of SUV mean, UVP post-acid stimulation and ΔUVP (all AUC<0.800; Z values: 2.09-4.65, all P<0.05). Conclusion:The quantitative parameters of parotid glands based on SUV acquired by dynamic SPECT/CT can reflect the damage degree of parotid glands in patients with pSS, providing novel quantitative analytical tools for the functional diagnosis and assessment of pSS.

Objective:To study the differences in the cumulative dose between deformable image registration (DIR) and simple dose-volume histogram (DVH) summation in the fractionated brachytherapy of cervical cancer, and to analyze the feasibility of the application of DIR in the dosimetry assessment of targets and organs-at-risk (OARs) in the brachytherapy.Methods:A retrospective analysis was conducted for 13 cases with primary cervical cancer treated with four fractions of interstitial brachytherapy guided by CT images. The four CT images of each cases were registered using an intensity-based DIR. Then, the cumulative doses (the D2 cm 3, D1 cm 3, and D0.1 cm 3 of the bladder, rectum, intestine, and colon and the D90for targets) after DIR were calculated and compared to those obtained using simple DVH summation. Afterward, the correlation between the dose difference and dice similarity coefficient (DSC) was analyzed. With the dose difference (the remaining dose of OARs caused by the DIR) as limits, a new plan was made for the latest CT to calculate the dose increase to targets. Results:Compared to simple DVH summation, DIR allowed the cumulative doses of the D2 cm 3 and D1 cm 3 of bladder to be decreased by (2.47±1.92) and (2.82±2.73) Gy, respectively on average ( t=-3.65, -2.93, P < 0.05), those of the D2 cm 3, D1 cm 3, and D0.1 cm 3 of rectum to be decreased by (2.05 ± 1.61) Gy, (1.51 ± 1.58), and (3.21 ± 2.50) Gy, respectively on average ( t=-4.02, -3.02, -4.06, P < 0.05), and those of the D2 cm 3, D1 cm 3, and D0.1 cm 3 to be decreased by (1.42 ± 0.99), (1.55 ± 1.28) Gy, and (2.43 ± 1.95) Gy, respectively on average ( t=-3.52, -2.96, -3.06, P < 0.05). There was no significant statistical difference in the D90 of targets, the D0.1 cm 3 of the bladder, and the D2 cm 3, D1 cm 3, D0.1 cm 3 of the colon ( P > 0.05) between both methods, and there was no distinct correlation between DSC and dose difference ( P > 0.05). The DIR increased the dose to targets, with a median value of 150 cGy. However, the accuracy of the DIR should be improved. Conclusions:In clinical practice of multiple fractions of brachytherapy for cervical cancer, it′s still recommended to adopt the simple dose summation method to assess the doses to targets and OARs.

Objective:To establish a dosimetric method based on the well-chamber to verify the accuracy of the source positioning and dwelling time for the afterloading machine, aiming to provide a new method for the quality control of afterloading machine.Methods:The principle of this method was explained according to the hardware structure of the well-chamber. Then, the precision of this method was analyzed by the simulation test and data fitting. The feasibility test was also performed. And the advantages and disadvantages of this method were compared with those of the traditional method.Results:The precision of this method for detecting the source positioning was 0.07 mm and the dwelling time was 0.09 s, respectively. In the feasibility test, the standard deviation of the measure value was below 3%.Conclusions:The well-chamber method has high precision and convenient operation. It can be applied in the rapid verification of the relative accuracy of the source positioning and dwelling time of well-chamber.

Objective: To study the feasibility of using the PTW729 2D array ion-chamber to verify the relative dose distribution calculated with the Acuros BV algorithm. Both advantages and disadvantages of the method were analyzed to provide reference for practical clinical practices. Methods: Based on self-built measurement phantoms, the dose distribution on the same slice of the phantom was measured with PTW729 and film, respectively, under the same measurement condition and plan. The dose distributions obtained by the two method were compared with the result calculated with Acuros BV, separately, by using γ analytical tool. And the stability of the PTW729 was tested. Results: The γ comparison value was 95.9% between the film and Acuros BV, 98.9% between the PTW729 and Acuros BV and 88.0% between the film and PTW729, with 95.0%, 100.0%, and 100.0%, in their stability test respectively. Conclusions PTW729 2D array ion-chamber can be applied to the rapid verification of Acuros BV algorithm-calculated relative dose distribution.

Objective: To compare the clinical application of three-dimensional laparoscopic pancreatoduodenectomy (3D-LPD) with that of two-dimensional laparoscopic pancreatoduodenectomy (2D-LPD), and to explore the safety and feasibility of 3D-LPD. Methods: A retrospective analysis was made from the data of 45 patients with 3D-LPD and 45 patients with 2D-LPD who underwent total laparoscopic pancreatoduodenectomy from March 2017 to August 2018 at Department of Hepato-Pancreato-Biliary Surgery, the First People′s Hospital of Changzhou.The differences of intraoperative conditions, postoperative complications and postoperative pathological findings between the two methods were compared.Measurement data were compared with independent sample t-test, enumeration data were statistically analyzed with Chi-square test or Fisher exact probability. Results: The operation time of 3D-LPD group was shorter than that of 2D-LPD group ((335±95) min vs. (419±113) min, t=-3.817, P=0.000), which mainly showed that the time of digestive tract reconstruction was reduced ((92±26) min vs. (131±46) min, t=-4.951, P=0.000). The intraoperative blood loss in the 3D-LPD group was significantly less than that in the 2D-LPD group ((242±124) ml vs. (350±176) ml, t=-3.365, P=0.001), and the perioperative blood transfusion in the 3D-LPD group was significantly less than that in the 2D-LPD group (χ²=4.444, P=0.035). Postoperative hospitalization days and ICU stay time were not significantly different between the two groups(both P>0.05). Postoperative complications such as pancreatic fistula, biliary fistula, postoperative bleeding, gastric emptying disorders, abdominal infection, were not significantly different between the two groups(all P>0.05). Conclusions The operation time of 3D-LPD is shorter than that of 2D-LPD, and the amount of bleeding is less. Short-term clinical data showed that, 3D-LPD is effective, safe and worth popularizing.

Objective: To study the learning curve of laparoscopic pacreaticoduodenectomy (LPD) with a view to find an appropriate way to develop LPD step by step. Methods: 112 consecutive patients who completely underwent LPD in a single surgery center at the First People’s Hospital of Changzhou from December 2015 to February 2018 were retrospectively reviewed. By using both the cumulative sum (CUSUM) and the risk-adjusted CUSUM (RA-CUSUM) methods to analyze the perioperative data of these patients, the learning curve of LPD was studied in a more scientific way. Results: The learning curve could be divided into three phases: Phase 1, the initial period (the initial 45 patients); Phase 2, the enhancement period (the subsequent 31 patients); Phase 3, the maturation period (the remaining patients). For these 3 phases, the corresponding operative times were (448.4±75.0), (381.3±74.3), and (336.2±52.1) min, respectively (P<0.05). The intraoperative blood losses were (373.3±250.1), (332.3±211.6), and (265.3±253.2) ml, respectively (P<0.05). The times to oral intake were 6.0(5.0, 8.0), 5.0(3.0, 6.0), and 3.0(3.0, 5.0) days, respectively (P<0.05). The number of lymph nodes harvested were (10.0±7.0), (8.8±4.3), and (13.3±6.2), respectively (P<0.05). All these showed significant improvement through the 3 phases. On the other hand, the postoperative stays, the postoperative pancreatic fistula rates were also decreased. But these failed to reach statistical significance. Vascular reconstruction was carried out in the 48th patient in phase 2 of the study. Conclusions The initial phase of LPD passed after LPD for 46 patients, but the maturation phase occurred after LPD on 76 patients. Vascular reconstruction should be considered as passing through the learning phase rather than reaching the maturity phase. Adjustments made in the enhancement phase helped to get through the maturation phase earlier.

Objective To discuss the commonly used puncturing approaches in CT-guided 125I seed implantation for lumbar lymph node metastases in order to provide safe and reliable technical guidance for clinical practice.Methods Under CT guidance,125I seed implantation for lumbar lymph node metastases was performed.According to different locations of metastatic lymphadenopathy (left waist,right waist or middle waist),the corresponding puncture route and implantation method were adopted.Meanwhile,different puncturing approach was designed in order to avoid damage to vital organs.Results For the performance of 125I seed implantation for the lymphadenopathy located at the left waist,right waist and middle waist,the commonly used puncturing approaches were percutaneous transthoracic lumboiliac costal muscle method (i.e.back approach),trans-hepatic trans-duodenal method (i.e.lateral approach) or back approach method,and trans-mesenteric approach together with coaxial needle method (i.e.anterior approach) respectively.Conclusion It is clinically feasible to use different puncturing approaches in performing 125I seed implantation for lumbar lymph node metastases,the suitable puncturing approach can ensure a successful and safe operation.

Objective To investigate the relationship of central venous pressure (CVP) and organ function in early period after orthotopic liver transplantation (OLT).Methods A retrospective study was conducted on 111 patients who underwent OLT.According to the value of mean CVP after OLT,all patients were divided into three groups:low CVP group (CVP＜8 rnmHg,1 rnmHg =0.133 kPa),normal CVP group (CVP 8-12 mmHg) and high CVP group (CVP ＞12 mmHg).Meanwhile,According to whether the CVP dropped below 8 mmHg or not in the past 48h after surgery,all patients were divided into two groups.Results There were significant differences in serum total bilirubin,serum creatinine and serum lactate among low,normal,and high CVP groups (P＜0.05).The time of vasoactive agent,fluid balance,time of mechanical ventilation and incidence of acute kidney injury in groups with CVP not dropped below 8 rnmHg were higher than those in groups with CVP dropped below 8 mmHg (P＜0.05).Conclusion CVP was associated with liver,kidney,lung function and lactate.Controlling a lower CVP can significantly shorten the time of mechanical ventilation and reduce the incidence of acute kidney injury after OLT.