Objective To investigate the effect of different strand lengths of 125I seeds with the same activity on the dose of different reference points around the seeds.Methods The scanned images were transferred to the three-dimensional treatment planning system(3D-TPS)according to DICOM format.The target volume was delineated at 5 mm and 10 mm above and below the center of the phantom,and a 0.8 mCi seeds strand was simulated.The 1-20 seeds were arranged with an equal spacing of 5 mm(5 mm-100 mm).The 5 mm points above and below the center of the seeds strand were defined as point A and point A',and the 10 mm points above and below the center were defined as point B and point B'.5 mm above and below the edge of the seeds strand on the left side were defined as AL points and AL'points,and 5 mm above and below the edge of the seeds strand on the right side were defined as AR points and AR'points.Similarly,points 10 mm above the above mentioned positions were defined as BL points,BL'points,BR points,BR'points.The average dose symmetry points were measured at AL,AL',AR,and 5 mm,10 mm,15 mm and 20 mm inside AR' of the 45 mm-100 mm seeds strand.The dose at the center was compared with the dose at the end points.The dose at the center point A was compared with the average dose at the symmetry points of 5 mm,10 mm,15 mm and 20 mm inside of the end points AL,AL',AR and AR',and the dose at each point was curve fitting.The correlation between each point and seeds strands of different lengths was analyzed.Results There was a positive correlation between the dose and the length of each point.There was no statistically significant difference between the center point and the end point.There was a statistically significant difference in dosage at points 5 mm and 10 mm inside from point A,while there was no statistically significant difference in dosage at points 15 mm and 20 mm inside from point A.The dose of A,A',B and B' point increased steadily with the increase of seed chain length,and the fitting curves were obtained respectively:y=e(-0.620/x+5.28)(R2=0.992),y=e(-0.640/x+5.34)(R2=0.987),y=e(-0.82/x+4.80)(R2=0.984),y=e(-0.82/x+4.83)(R2=0.9g1).Conclusion The doses at points A,A',B,and B'are positively correlated with seeds strand length and have a high degree of stability.Point A can be used as a reference point for the target area dose of the seeds strand,and point B can be used as a reference point for the dose to critical organs.The dose at other positions is more variable and thus has a certain degree of uncertainty as a reference point for the seeds strand dose.

Objective To investigate the relationship between the absorbed dose and implantation duration at the target area and at the critical organ dose reference points in the application of radioactive 125I seed strands for the treatment of intraluminal tumors.Methods A self-developed 125I seed strand arc template with a 30-degree angle was used to place 10 seeds(each with activity of 1.0mCi)into the template.CT-based DICOM images were transferred to a treatment planning system(TPS)for dose calculation.Absorbed doses at multiple time points(from day 5 to day 90 with a 5-day interval)were measured at following four specific locations:point A'(5 mm inside the arc center),point A(5 mm outside the arc center),point B(10 mm outside the arc center),and point B'(10 mm inside the arc center).The TPS was first used to calculate the expected absorbed doses,followed by actual absorbed dose measurements over the 90-day period.The expected absorbed doses were calculated,and then the actual absorbed doses were calculated.The time-dose relationship of the above points was analyzed,and the curves and equations were obtained.Results The expected absorbed doses at points A',A,B,and B'were 221.36,196.39,115.78,and 136.32 Gy,respectively.The time(x)-dose(y)relationships of all the above points followed a quadratic function relationship in the form of y=c+bx-ax2.Within the time range of 5-90 days,the actual absorbed dose increased with the prolongation of time,and the increase speed showed a pattern of first fast and then slow.The increase in speed was fast within 20 days,than became stable between 20-75 days,and after 75 days the increase in speed became to slow down.Conclusion When using 125I seed strands to treat intraluminal tumors,the actual absorbed dose of the tumor needs to be accurately calculated based on the implantation duration.The actual absorbed dose initially accumulates rapidly and decreases significantly after 75 days.It is recommended to replace the 125I seed strand with a new one after implanting it for approximately 75 days.

Objective To investigate the impact of different 125I seeds strand radian on the dose of different reference points around the seeds.Methods CT scan of self-developed radioactive particle radiation dose measurement phantom was performed,the scanned images were transferred to the three-dimensional treatment planning system(TPS).The target area at the middle level of the model was drawn.The target volume was delineated at 5 mm and 10 mm above and below the center of the phantom.125I seeds strand plans were designed with different radians,with a total length of 8 cm,seed spacing of 0 cm,activity of 0.8 mCi,and a total of 16 particles,with radians ranging from 30°to 170°,increasing by 10° increment.The point 5 mm vertically away from the center of the seeds strand towards the center was named A',and the point away from the center was named A.The point 10 mm vertically away from the center of the seeds strand towards the center was named B',and the point away from the center was named B.The doses at different radians were recorded,and the actual absorbed dose at 1-2 months after operation was calculated based on the particle activity decay formula.Results The doses at points A'and A were(218.3±23.1)and(201.5±16.0)Gy respectively(P=0.001).The actual absorbed doses at 1 month after operation were(65.5±6.9)and(60.5±4.8)Gy respectively(P=0.001),and the actual absorbed doses at 2 months after operation were(109.2±11.5)Gy and(100±7.9)Gy respectively(P=0.001).The doses at points B'and B were(95.9±11.0)Gy and(81.7±4.9)Gy respectively(P＜0.001),and the actual absorbed doses at 1 month after operation were(28.8±3.3)Gy and(24.5±1.5)Gy respectively(P＜0.001).The actual absorbed doses at 2 month after operation were(48.0±5.5)Gy and(41.0±2.4)Gy respectively(P＜0.001).The doses at points A'and A gradually decreased with the increase of the radians,reaching the minimum value at 100 degrees,and then increased gradually,showing a cubic function change.The actual absorbed dose showed the same trend.The doses at points B'and B increased gradually with the increase of the radians,showing a cubic function change.Conclusion At different radians,the point doses and absorbed doses on the centrifugal side of the seeds strand are both less than those on the centripetal side.There is a cubic function relationship between the dose at the reference points and the radian of the seeds strand.

Background and purpose:Thyroid cancer is the most common malignant endocrine tumor,particularly prevalent among the Asian population.The overall survival for thyroid cancer patients is relatively high,but there are significant survival differences among patients.Based on long-term hospital-based cancer registry database,this study analyzed the 10-year observed overall survival(OS)rate of thyroid cancer cases and the distribution of causes of death,providing real-world evidences to further survival management of thyroid cancer in China.Methods:A total of 55343 thyroid cancer patients who underwent treatment at Fudan University Shanghai Cancer center from 2005 to 2021 were included in this study.Clinical information and the follow-up endpoint data were collected through medical records review,telephone visits and death registry data linkage.The last follow-up date was October 31,2024.Kaplan-Meier method was applied in evaluating the OS rate,and survival data were described by different subgroups as age group,gender,treatment period,tumor staging and pathological characteristics.The standardized mortality ratio(SMR)and absolute excess risk(AER)were calculated using general Shanghai population as the reference,and the mortality risk was described by gender,age at diagnosis and histological subtype.Results:With a median follow-up time of 63.01 months,the overall 1-,3-,5-and 10-year OS rates of thyroid cancer patients were 99.67%(95%CI:99.62%-99.72%),99.11%(95%CI:99.03%-99.19%),98.48%(95%CI:98.36%-98.60%)and 95.81%(95%CI:95.50%-96.11%),respectively.The 10-year OS rates of stage Ⅰ,Ⅱ,Ⅲ and Ⅳ were 97.99%(95%CI:97.70%-98.28%),89.80%(95%CI:87.24%-92.37%),77.84%(95%CI:70.76%-84.92%)and 62.95%(95%CI:55.37%-70.54%),respectively.The differences in OS among patients with different age,gender and histological classification were significant.1256(2.27%)deaths occurred,of which 18.63%,50.88%and 7.32%were attributable to thyroid cancer,other cancers and cardiovascular disease(CVD),respectively.Compared with the general population,patients with different subtypes of thyroid cancer had higher all-cause mortality rates,progressively increasing with papillary,follicular,medullary and anaplastic thyroid carcinoma/poorly differentiated carcinoma.Compared with general population,the death risk was 2.24 times higher in papillary thyroid cancer patients(95%CI:2.06-2.44),9.94 times higher in follicular thyroid cancer patients(95%CI:6.79-14.09),12.16 times higher in medullary thyroid cancer patients(95%CI:8.05-17.69),and the highest risk was observed in patients with anaplastic thyroid carcinoma/poorly differentiated carcinoma[SMR=79.67(95%CI:58.38-106.31),AER=766.01/1 000 person-years].Conclusion:The 10-year long survival data and cause of death for thyroid cancer patients with different histological types were reported in China based on a large single institution hospital-based cancer registry database.Staging and histological characteristics were the most important factors directly affected the survival.Early diagnosis and individualized treatment are crucial for improving prognosis.

Objective:To investigate the efficacy and influencing factors of iodine-125 seed implantation in the treatment of recurrent radioiodine refractory differentiated thyroid carcinoma (RAIR-DTC) .Methods:Retrospective analysis of 18 patients with recurrent RAIR-DTC treated with iodine-125 particle implantation at Ward One, Department of Oncology, Hebei General Hospital from Sept. 2015 to Mar. 2022 was performed. A total of 35 lesions were involved, all permanently implanted with iodine-125 particles under image guidance, with particle activity ranging from 0.3mCi to 0.8mCi, and prescription doses ranging from 80 to 140 Gy. The study observed the objective response rate, local control rate, survival rate, adverse reactions, and factors influencing treatment efficacy.Results:After a follow-up period of 8 to 115 months,according to the objective efficacy evaluation criteria of solid tumors 1.1,the objective response rates were 51.4% (18/35) ,80.0% (28/35) ,68.6% (24/35) ,60.0% (21/35) ,42.9% (15/35) at 3,6,12,24,36 months postoperatively,respectively.The local control rates were 100% (35/35) ,100% (35/35) ,80.0% (28/35) ,62.9% (22/35) ,51.4% (18/35) at 3,6,12,24,36 months postoperatively,respectively.The 1-,2-, and 3-year postoperative survival rates were 83.3% (15/18) ,72.2% (13/18) ,61.1% (11/18) ,respectively.During the follow-up period,4 patients developed progressive lesions in the target area.One grade I radioactive skin injury,one grade Ⅱ radioactive skin injury,and no residual particle-related adverse reactions.The results of multivariate analysis showed that D90,tumor involvement of the esophagus were the factors influencing the recent efficacy.The area under the ROC curve for D90 was 0.804 with the best bound of 106.5Gy.Conclusion:Iodine-125 particle implantation is safe and effective for recurrent RAIR-DTC.D90,tumor involvement of the esophagus are the influencing factors of the recent efficacy,and the D90≥106.5Gy treatment effect is better.

Objective To explore the clinical application value of CT radiomics in predicting the grade of liver cancer and the prognosis after hepatectomy.Methods A retrospective selection was conducted on 385 liver cancer patients who underwent preoperative CT scans,and they were divided into training group(265 cases)and testing group(120 cases).The CT radiomics features were extracted and logistic regression was used to construct radiomics markers.A retrospective analysis was performed on 60 patients with liver cancer who underwent hepatectomy and regular follow-up.Results The area under the curve(AUC)of the radiomics signature in the train-ing group was 0.889.The AUC in the testing group was 0.941.For predicting prognosis after hepatectomy,the radiomics features with filter parameter of Filter 1.0 achieved optimal performance,with Dif.Scale1.2 being a good independent predictor of overall survival(OS).Conclusion CT radiomics has certain application value in predicting the grade of liver cancer and the prognosis after hepatectomy.

Objective:To investigate the efficacy and influencing factors of iodine-125 seed implantation in the treatment of recurrent radioiodine refractory differentiated thyroid carcinoma (RAIR-DTC) .Methods:Retrospective analysis of 18 patients with recurrent RAIR-DTC treated with iodine-125 particle implantation at Ward One, Department of Oncology, Hebei General Hospital from Sept. 2015 to Mar. 2022 was performed. A total of 35 lesions were involved, all permanently implanted with iodine-125 particles under image guidance, with particle activity ranging from 0.3mCi to 0.8mCi, and prescription doses ranging from 80 to 140 Gy. The study observed the objective response rate, local control rate, survival rate, adverse reactions, and factors influencing treatment efficacy.Results:After a follow-up period of 8 to 115 months,according to the objective efficacy evaluation criteria of solid tumors 1.1,the objective response rates were 51.4% (18/35) ,80.0% (28/35) ,68.6% (24/35) ,60.0% (21/35) ,42.9% (15/35) at 3,6,12,24,36 months postoperatively,respectively.The local control rates were 100% (35/35) ,100% (35/35) ,80.0% (28/35) ,62.9% (22/35) ,51.4% (18/35) at 3,6,12,24,36 months postoperatively,respectively.The 1-,2-, and 3-year postoperative survival rates were 83.3% (15/18) ,72.2% (13/18) ,61.1% (11/18) ,respectively.During the follow-up period,4 patients developed progressive lesions in the target area.One grade I radioactive skin injury,one grade Ⅱ radioactive skin injury,and no residual particle-related adverse reactions.The results of multivariate analysis showed that D90,tumor involvement of the esophagus were the factors influencing the recent efficacy.The area under the ROC curve for D90 was 0.804 with the best bound of 106.5Gy.Conclusion:Iodine-125 particle implantation is safe and effective for recurrent RAIR-DTC.D90,tumor involvement of the esophagus are the influencing factors of the recent efficacy,and the D90≥106.5Gy treatment effect is better.

Objective To explore the clinical application value of CT radiomics in predicting the grade of liver cancer and the prognosis after hepatectomy.Methods A retrospective selection was conducted on 385 liver cancer patients who underwent preoperative CT scans,and they were divided into training group(265 cases)and testing group(120 cases).The CT radiomics features were extracted and logistic regression was used to construct radiomics markers.A retrospective analysis was performed on 60 patients with liver cancer who underwent hepatectomy and regular follow-up.Results The area under the curve(AUC)of the radiomics signature in the train-ing group was 0.889.The AUC in the testing group was 0.941.For predicting prognosis after hepatectomy,the radiomics features with filter parameter of Filter 1.0 achieved optimal performance,with Dif.Scale1.2 being a good independent predictor of overall survival(OS).Conclusion CT radiomics has certain application value in predicting the grade of liver cancer and the prognosis after hepatectomy.

Background and purpose:Thyroid cancer is the most common malignant endocrine tumor,particularly prevalent among the Asian population.The overall survival for thyroid cancer patients is relatively high,but there are significant survival differences among patients.Based on long-term hospital-based cancer registry database,this study analyzed the 10-year observed overall survival(OS)rate of thyroid cancer cases and the distribution of causes of death,providing real-world evidences to further survival management of thyroid cancer in China.Methods:A total of 55343 thyroid cancer patients who underwent treatment at Fudan University Shanghai Cancer center from 2005 to 2021 were included in this study.Clinical information and the follow-up endpoint data were collected through medical records review,telephone visits and death registry data linkage.The last follow-up date was October 31,2024.Kaplan-Meier method was applied in evaluating the OS rate,and survival data were described by different subgroups as age group,gender,treatment period,tumor staging and pathological characteristics.The standardized mortality ratio(SMR)and absolute excess risk(AER)were calculated using general Shanghai population as the reference,and the mortality risk was described by gender,age at diagnosis and histological subtype.Results:With a median follow-up time of 63.01 months,the overall 1-,3-,5-and 10-year OS rates of thyroid cancer patients were 99.67%(95%CI:99.62%-99.72%),99.11%(95%CI:99.03%-99.19%),98.48%(95%CI:98.36%-98.60%)and 95.81%(95%CI:95.50%-96.11%),respectively.The 10-year OS rates of stage Ⅰ,Ⅱ,Ⅲ and Ⅳ were 97.99%(95%CI:97.70%-98.28%),89.80%(95%CI:87.24%-92.37%),77.84%(95%CI:70.76%-84.92%)and 62.95%(95%CI:55.37%-70.54%),respectively.The differences in OS among patients with different age,gender and histological classification were significant.1256(2.27%)deaths occurred,of which 18.63%,50.88%and 7.32%were attributable to thyroid cancer,other cancers and cardiovascular disease(CVD),respectively.Compared with the general population,patients with different subtypes of thyroid cancer had higher all-cause mortality rates,progressively increasing with papillary,follicular,medullary and anaplastic thyroid carcinoma/poorly differentiated carcinoma.Compared with general population,the death risk was 2.24 times higher in papillary thyroid cancer patients(95%CI:2.06-2.44),9.94 times higher in follicular thyroid cancer patients(95%CI:6.79-14.09),12.16 times higher in medullary thyroid cancer patients(95%CI:8.05-17.69),and the highest risk was observed in patients with anaplastic thyroid carcinoma/poorly differentiated carcinoma[SMR=79.67(95%CI:58.38-106.31),AER=766.01/1 000 person-years].Conclusion:The 10-year long survival data and cause of death for thyroid cancer patients with different histological types were reported in China based on a large single institution hospital-based cancer registry database.Staging and histological characteristics were the most important factors directly affected the survival.Early diagnosis and individualized treatment are crucial for improving prognosis.

Objective:To investigate the incidence of radiation pneumonitis (RP) induced by 125I seed implantation for the treatment of malignant lung tumors and analyze related dosimetric parameters. Methods:A retrospective analysis was conducted on 31 cases of malignant lung tumors treated with 125I seed implantation from January 2017 to December 2022 at Hebei Provincial Tumor Radioactive Seeds Implantation Diagnosis and Treatment Center. These cases consisted of eight patients with squamous cell carcinoma, 10 patients with adenocarcinoma, and 13 patients with metastatic cancer in other sites. At 1-6 months after treatment, these patients received postoperative chest CT scans, with the efficacy evaluated based on the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1), including the objective response rate (ORR) and the disease control rate (DCR). The efficacy of RP was evaluated using the Radiation Therapy Oncology Group (RTOG) criteria. Postoperative dosimetric parameters, including D90 (minimum peripheral dose received by 90% of the target volume), V8 (percentage of lung volume receiving 8 Gy), V32 (percentage of lung volume receiving 32 Gy), and Dmean (mean radiation dose) of the affected lung, were statistically analyzed. The relationships of the RP occurrence with postoperative D90, V8, V32, and Dmean were analyzed by comparison with relevant external radiotherapy data, to identify the parameters that are correlated closely with RP occurrence. Results:All the patients underwent successful surgeries. The postoperative efficacy evaluation after six months showed complete response (CR) in 11 cases, partial response (PR) in 11 cases, stable disease (SD) in eight cases, and progressive disease (PD) in one case, with an overall response rate (ORR) of 71.0%, and a disease control rate (DCR) of 96.8%. Three patients suffered RP, with an incidence rate of 9.7%. Postoperative V8, V32, and Dmean could not serve as predictive indicators for RP. Follow-up observation revealed that three RP cases (3/5) exhibited postoperative D90 exceeding 170 Gy and no RP cases (0/26) showed postoperative D90 below 170 Gy. Conclusions:In the treatment of malignant lung tumors with 125I seed implantation, there is a certain correlation between RP and postoperative D90, while there is no correlation between it and V8, V32, and Dmean.