[Validation of calculation method for dose distribution around radioactive iodine-125 particles based on AAPM TG43 report].

Objective: According to the formula provided by the TG43 report [AAPM TG43 (2004)] proposed by the American Association of Physicists in Medicine (AAPM) in 2004, we calculated the dose distribution around the radioactive iodine-125 particles, and verified the calculation accuracy of the radioactive iodine-125 particles treatment planning system. Methods: AAPM TG43 (2004) report provides two calculation methods when calculating the dose around a single radioactive source. The calculation method that does not consider the geometric structure of the radioactive source is called point source calculation method, and the calculation method that considers the geometric structure of the radioactive source is called line source calculation method. Assuming a single Amersham 6711 radioactive iodine-125 particle with an activity of 100 U, the following point doses were calculated according to the two calculation methods provided by AAPM TG43 (2004) report, at 0°, 90° directions, distances 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5 and 6 cm; In the direction of 45°, the doses at 0.71, 1.41, 2.12, 2.83, 3.54, 4.24, 4.95, 5.66, 6.36, 7.07, 7.78 and 8.49 cm. On the clinically used brachytherapy planning system variseeds 8.0, the above two calculation methods are used to calculate the corresponding activity and the dose around the corresponding type of radioactive iodine-125 particles, and the function of capturing points to templates built in the planning system is used to accurately find the above corresponding point position, using a single measurement of the above corresponding point dose; and comparation of the results were performed to see if there is a statistical difference. Results: The AAPM TG43 report uses point source calculation method to calculate the dose of single Amersham 6711 radioactive iodine-125 particles with activity of 100 U at 0° and 90° directions. The points with the same distance and the same dose are 8 082.18, 1 870.08, 756.58, 381.47, 217.11, 131.91, 86.55, 58.32, 39.97, 27.42, 19.74, 14.13 Gy, respectively, at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5 and 6 cm away from them. In the 45° direction, the doses at the distances of 0.71, 1.41, 2.12, 2.83, 3.54, 4.24, 4.95, 5.66, 6.36, 7.07, 7.78 and 8.49 cm are 3 957.37, 865.83, 329.99, 155.69, 84.10, 48.50, 28.49, 17.80, 11.37, 7.38, 4.98 and 3.39 Gy, respectively; For line source calculation method, radioactive particles are at the same distance as above. The doses at each point in the direction of 0° are 3 128.71, 755.44, 330.30, 180.53, 107.74, 68.56, 46.40, 32.22, 22.70, 16.00, 11.51, 8.24 Gy, respectively. The doses at each point in the direction of 90° are 8 306.46, 1 981.01, 802.74, 405.38, 230.60, 140.03, 91.83, 61.84, 42.36, 29.05, 20.91, 14.97 Gy; In the 45° direction, the dose at the corresponding distance as above is 4 020.78, 877.43, 333.49, 156.93, 84.69, 48.81, 28.65, 17.89, 11.42, 7.41, 4.99 and 3.40 Gy, respectively. The maximum dose difference (0.3%) between the two methods is 7.78 cm in the 45° direction, the maximum difference (-0.3%) between the two methods is 8.49 cm in the 45° direction, and the value of other sampling points is less than 0.3%. The closer the Amersham 6711 iodine-125 particles are to the source in the directions of 0°, 45°, and 90°, the faster the dose will drop, and the dose will drop gradually as the distance increases. Conclusion: The brachytherapy planning system variseeds 8.0 and the AAPM TG43 report calculate a maximum dose difference of 0.3%, which can accurately calculate the dose distribution around radioactive iodine-125 seeds, and provide a reliable tool for the clinical implementation of radioactive iodine-125 particles implantation for tumor treatment.

[3D printing non-coplanar template-assisted 125-iodine seed implantation for thorax movement tumor: individual template design method].

Objective: To compare the dosimetric data between preoperative plans and postoperative verification in computed tomography CT-guided and 3D printing template-assisted 125-iodine ((125)I) seed implantation for thorax movement tumor and to explore the feasibility and accuracy of the individualized template design method. Methods: A total of 35 patients, 20 males and 15 females with median age of 62 (17-87) years old, who registered from January 2016 to December 2017 applied with 3D printing guided template assisted radioactive seed implantations in Peking University Third Hospital were included in this study. (125)I seeds with a prescribed dose of 110-180 Gy were impanted. 3D printing templates were designed and produced for 35 cases. The dosimetric parameters: D(90), minimum peripheral dose (mPD), V(100), V(150), V(200), conformal index (CI), external index (EI), and homogeneity index (HI) were compared between pre-and post-plannings. Statistical method was two group of related non-parameters test. Results: The design and production of 35 cases' templates were in place well. Compared with the preoperative planning, the postoperative D(90), V(100), V(150), V(200), mPD, CI, EI and HI differences were 5.57%, 0.34%, 0.33%, -1.20%, 21%, 2.8%, -14.2%, 4.71%, -10.4%. All the included dosimetry parameters changed slightly after surgery compared with before surgery, but the difference was not statistically significant(all P>0.05). Conclusions: The dosimetric parameters of postoperative verification are consistent well with the preoperative planning and have good accuracy, the results could meet the clinical requirements.

[Comparison of preoperative planning of radioactive seed implantation for pelvic wall recurrent gynecological malignant tumors between 3D-printing non-coplanar template and 3D-printing coplanar template].

Objective: To compare the difference of preoperative planning parameters between 3D-printing non-coplanar template (3D-PNCT) and 3D-printing coplanar template (3D-PCT) in the treatment of pelvic wall recurrent gynecological malignant tumor with radioactive seeds implantation, and to guide the clinical application. Methods: From January 2016 to March 2018, 33 patients with pelvic wall recurrent gynecological malignant tumor were treated with radioactive seeds implantation assisted by 3D-printing template and in Peking University Third Hospital. All patients underwent 3D-PNCT and 3D-PCT preoperative planning. The D(90) of target remained similar for the same patient. The parameters were compared with Wilcoxon test or Kruskal-Wallis test. Results: D(90) was similar between the two groups (P>0.05). The number of inserting needles through intestine and bone in 3D-PNCT group was less than that in 3D-PCT group (0 (0-13), 0 (0-25), Z=-2.941, P<0.05;0 (0-3), 0 (0-25), Z=-2.232, P<0.05). Conclusion: For patients with gynecological malignancies with pelvic recurrence, both of the two peroperative plans could achieve prescription dose, but 3D-PNCT is more safer.

[CT-guidance interstitial Iodine-125 seed brachytherapy as a salvage therapy for recurrent head and neck carcinoma].

Objective: To investigate the efficacy of CT-guidance interstitial Iodine-125 seed brachytherapy as a salvage therapy for recurrent head and neck carcinoma. Methods: A total of 122 patients who had been treated for recurrent head and neck carcinoma with CT-guided Iodine-125 seed permanent implantation were conducted a retrospective analysis at Peking University Third Hospital from February 2003 to December 2015. The study included 78 male and 44 female patients. Of the 122 patients, 76 had undergone radical surgery, 106 had received EBRT. Among the patients who underwent EBRT, the total dose delivered to PTV ranged from 30 to 140 Gy (median, 68.4 Gy). The actuarial median number of the implanted Iodine-125 seeds was 38 (range, 5-158). The specific activity of Iodine-125 seeds ranged from 14.8 to 28.9 MBq/seed (median, 22.2 MBq). The evaluation of post plan showed the actuarial D90 ranged from 46 to 282 Gy (median, 121 Gy). The overall local control and survival times were determined by using the Kaplan-Meier method from SPSS 13.0.Univariate analysis was performed on the local control rate and overall survival rate. Results: Tumor responses rate was 75.4%. The median local control time was 10.0 months (95% CI 9.8-24.2 months), and the 1-, 2-, 3-, and 5-year local control were 41.9%, 21.2%, 3.7%, and 3.7%, respectively. Univariate analysis showed that the local control in D90≥120 Gy group had an increasing tendency, but no statistical difference were found. The effect of local control in the squamous cell carcinoma group was slightly worse than that in the non-squamous cell carcinoma group (P=0.032). Multi-factor analysis showed that the effect of local control in the squamous cell carcinoma group was slightly poor (P=0.03). The median survival time was 14 months (95% CI 14.4-35.8 months), and the 1-, 2-, 3- and 5-year survival rate were 51.5%, 34.2%, 19.4%, and 19.4%, respectively. The three factors, such as the tumor responses, KPS status before the seed implantation, and the D90 after the seed implantation, had a tendency to improve the total survival, but there was still no statistical differences. Multivariate analysis showed no clear influence factors. Conclusions: Interstitial permanent Iodine-125 seed implantation is an effective salvage re-irradiation modality for recurrent head and neck carcinoma after previous surgery and/or EBRT. CT image-guided method could yield the reliable seeds configuration and accurate dose distribution.

[Efficacy and dosimetric analysis of (125)I seeds implantation for pelvic recurrent cervical cancer after radiotherapy under CT guidance].

Objective: To evaluate the relationship of dosimetry parameters and efficacy of (125)I seeds implantation for pelvic recurrent cervical cancer (PRCC) after external beam radiotherapy(EBRT) under CT guidance. Methods: A retrospective analysis was made on 30 PRCC patients after EBRT in Peking University Third Hospital with (125)I seeds implantation under CT guidance. Postoperative plans were made to evaluate the dosimetric parameters. Kaplan-Meier method was used to calculate local progression free survival (LPFS) rate and overall survival (OS) rate, and Log-rank test and Cox regression were used for univariate and multivariate analysis. Results: The 1-year and 2-year LPFS rate was 39.4% and 22.5%, respectively. The 1-year and 2-year OS rate was 57.3% and 27.4%, respectively. On postoperative plan, D(90) was (132±47) Gy, D(100) was (51±24) Gy, V(100) was 88%±10%, V(150)was 69%±15%, V(200) was 51%±18%.LPFS time would be longer while D(90) ≥105 Gy or D(100) ≥ 55 Gy or V(100) ≥ 91% (all P<0.05). D(100) was significantly related to LPFS (P<0.05). But these dosimetry parameters got no effect on OS. Conclusions: LPFS time of (125)I seeds implantation for PRCC after EBRT under CT guidance would be longer when D(90)≥105 Gy or D(100)≥ 55 Gy, or V(100)≥ 91%. D(100) is an independent factor related to LPFS.

[Brachytherapy treatment planning calculation (125)I particle esophageal stent dosimetric study].

Objective: To investigate the dosimetric distribution characteristics of (125)I seed stents with different seed spacing, diameter and length, as well as different (125)I seed activity. The dosimetry table of (125)I seed esophageal stent was derived to provide dosimetry for its clinical application. Methods: The self-expanding coated esophagus stent was designed to carry radioactive (125)I seeds with different length, diameter and seed spacing. A cylindrical organic glass model (Thickness 0.8 cm, diameter 20 cm, height 20 cm) was fixed vertically to a cylindrical organic glass containing a solid paraffin (analytical pure) solution. After paraffin cooling and solidification, CT scan was used to transmit image information to TPS. With the center of the bracket as a dot, the cumulative dose at a distance of 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 5.0, 6.0 and 8.0 cm away from the dot was simulated respectively in 0° and 9° direction. Results: The radial cumulative dose with the seed spacing which was 1.0 and 1.5 cm were different by 4.8%, 5.8%, 7.2%, 8.0%, 8.6% and 13.3% respectively under the exposure of 18.5, 22.2, 25.9, 29.6, 33.3 and 37.0 MBq. When the seed spacing was the same as the length of the stent, the radial cumulative dose with the stent which diameter was 1.3, 2.0, 2.4 cm were different by 4.9% vs 3.4%, 4.7% vs 3.8%, 5.4% vs 6.6%, 4.5% vs 5.3%, 4.7% vs 4.8%, 4.8% vs 5.4% respectively under the exposure of 18.5, 22.2, 25.9, 29.6, 33.3 and 37.0 MBq. When the seed spacing was the same as the diameter of the stent, the radial cumulative dose with the stent which length was 8, 12, 16 cm were different by 1.9% vs 1.2%, 1.7% vs 0.8%, 1.6% vs 1.3%, 1.9% vs 1.5%, 1.7% vs 1.8%, 1.6% vs 1.3% respectively under the exposure of 18.5, 22.2, 25.9, 29.6, 33.3 and 37.0 MBq. Conclusions: The radial cumulative dose of the (125)I seed stent is positively correlated with the activity of the radioactive seeds, Which means the dose rate of a certain point of the (125)I seed stent increase with the increase of the activity of the radioactive seeds. The stent of the (125)I radioactive seeds is negatively correlated with the distance, the dose rate of the (125)I seed stents decrease rapidly with the increase of distance.

[Study of comparing dexmedetomidine and remifentanil for conscious sedation during radiofrequency ablation of hepatocellular carcinoma].

Objective: This study aimed to compare dexmedetomidine with remifentanil for conscious sedation in patients undergoing radiofrequency ablation of hepatocellular carcinoma. Methods: Sixty patients, who were aged 41 to 73 years with American Society of Anesthesiologists (ASA) physical status Ⅰ-Ⅱ, and scheduled for elective radiofrequency ablation of hepatocellular carcinoma under conscious sedation in National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, from January 2014 to June 2016, were allocated randomly to receive dexmedetomidine maintenance regimen(group D, n=30)or remifentanil maintenance regimen(group R, n=30)by random digital table. Subjects in group D received dexmedetomidine at a loading dose of 0.5 µg/kg over 10 min followed by 0.2-1.0 µg·kg(-1)·h(-1) infusion until Ramsay sedation scale reached 3-4. Patients in group R received a loading dose of remifentanil 1 µg/kg followed by remifentanil 4-10 µg·kg(-1)·h(-1) infusion and propofol 1-2 mg·kg(-1)·h(-1) infusion until Ramsay sedation scale reached 3-4. Haemodynamic variables, respiratory rate(RR), pulse oxygen saturation (SpO(2))and numeric rating scales(NRS) in each group were collected at entrance(T(0)), puncturing(T(1)), 15 min after beginning of radiofrequency ablation(T(2)), the end of radiofrequency ablation(T(3)) and 30 min after operation(T(4)). Efficacy of anesthesia, incidences of intraoperative respiratory depression, postoperative nausea and vomiting, patient and surgeon satisfaction were evaluated. Results: Compared with group D, the arterial blood pressure and heart rate at T(2) [(92.2±15.7)mmHg vs (102.4±16.7)mmHg, (69.7±15.3) beats/min vs (79.4±17.7) beats/min] and respiratory rate at T(1), T(2) and T(3) [(10.1±1.9) breaths/min vs(12.3±1.7) breaths/min, (10.8±1.5) breaths/min vs(13.6±1.6) breaths/min, (13.4±1.6) breaths/min vs(14.5±1.4)breaths/min] were significantly lower in group R (t=-2.437, -2.271, -4.726, -6.993, -2.834, all P<0.05). With less sulfentanil consumption(23.2±8.3)µg vs( 35.5±11.7)µg, group R got less NRS at T(2) and T(3)(2.4±1.1) vs(3.5±1.2), (2.4±1.3) vs(3.6±1.1), and higher NRS at T(4)(3.4±1.1) vs( 2.1±0.9) than group D(t=-4.696, -3.701, -3.860, 5.010, all P<0.05). Compared with group R, the incidence of intraoperative respiratory depression was significantly lower (23.3% vs 56.7%)and the incidence of inadequate anesthesia(20% vs 0) was significantly higher in group D(χ(2)=5.625, 4.630, both P<0.05). Conclusion: Both dexmedetomidine and remifentanil can be successfully used for conscious sedation in patients undergoing radiofrequency ablation of hepatocellular carcinoma. Remifentanil maintenance regimen provides better intraoperative analgesia and operative condition, while dexmedetomidine is superior to remifentanil in reducing intraoperative respiratory depression and postoperative pain.

[Dosimetric analysis of volumetric modulated arc therapy and intensity modulated radiotherapy for patients undergone breast-conserving operation].

OBJECTIVE: To compare the dosimetric differences between volumetric modulated arc therapy and intensity modulated radiotherapy for breast cancer patients after breast-conserving surgery. METHODS: Ten patients who received radiotherapy after breast-conserving surgery were selected. Eclipse planning system was used to design volumetric rotating intensity-modulated (2F-RapidArc) and two field intensity-modulated radiation therapy (2F-IMRT) planning for each patient. 2F-RapidArc plans were made using two partial arcs with gantry rotation from 287°-293° to 152°-162°, and 0° to 90 ° was avoidance sector. The gantry angle of 2F-IMRT were 301°-311° and 125°-135°. The prescription dose was 46 Gy/23 fractions. All plans required 95% of the target volume receiving the prescription dose. The dose distribution of the target, organs at risk, machine unit (MU) and treatment time were compared. RESULTS: 2F-RapidArc and 2F-IMRT plans' uniformity index was 1.12±0.02 and 1.11±0.03 (P=0.282), respectively; conformal index was 0.80±0.03 and 0.65±0.04 (P<0.001), respectively. V110 of plan target volume was 20.98%±14.47% and 10.43%±10.49% (P=0.030), respectively. Compared with the 2F-IMRT, 2F-RapidArc plans had a higher dosimetric parameters for left lung: V5 (48.06%±17.32% vs. 24.23%±6.56%,P=0.001), V10 (28.89±9.28 vs.17.07±4.78%,P=0.004), Dmean [(9.70±2.14) Gy vs. (6.86±1.77) Gy, P=0.002], increased the double lung: V5 (22.85%±7.55% vs. 11.01%± 2.95%,P=0.001), V10 (13.16%±4.33% vs. 7.76%± 2.16%, P=0.006), Dmean [(4.66±0.95) Gy vs. (3.17±0.82) Gy, P=0.001], reduced the left lung: V40 (3.58%±1.46% vs. 6.19%±3.04%, P=0.006), reduced the double lung: V40 (1.61%±0.64% vs. 2.81%± 1.39%,P=0.005), increased cardiac: V5 (39.3%±17.19% vs. 8.79%±4.24%, P<0.001), V10 (21.31%±13.8% vs. 5.73%±3.42%, P=0.002), V20 (7.80%±6.08% vs. 4.05%±2.85%,P=0.018), Dmean [(0.64±0.25) Gy vs. (0.29±1.39) Gy,P<0.001],reduced the heart: V40(0.50%±0.40% vs. 1.86%±1.94%,P=0.037),increased the contralateral breast Dmean [(1.63±1.26) Gy vs. (0.09±0.05) Gy, P=0.004]. Compared with 2F-IMRTplan, 2F-RapidArc increased the treatment time [(132.9±7.2) s vs. (140.3±11.6) s, P=0.030]. Both the machine units were almost the same [(467.0±30.4) MU vs. (494.7±44.9) MU, P=0.094]. CONCLUSION: Both 2F-RapidArc and 2F-IMRT plans could reach the clinical requirements. 2F-RapidArc had a better conformal index, reduced the high dose area, but increased the low dose regions of the lung, heart, body area, and increased the average dose of the contralateral breast. The treatment time of 2F-RapidArc was longer than that of 2F-IMRT, and the MU of 2F-RapidArc and 2F-IMRT plans were almost the same.

[Study of sevoflurane/remifentanil coadministration on improving emergence and recovery characteristics of patients following general anaesthesia with sevoflurane].

Objective: To investigate the effects of remifentanil infusion on emergence and recovery characteristics of patients with thoracoscopic lobectomy following general anaesthesia with sevoflurane. Methods: One hundred patients, who were aged 37 to 65 years with American Society of Anesthesiologists (ASA) physical status 1-2, and scheduled for elective thoracoscopic lobectomy under general anaesthesia in National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, from February 2016 to August 2016, were allocated to receive sevoflurane maintenance regimen(group S, n=50)or sevoflurane/remifentanil maintenance regimen(group SR, n=50)by random digital table. After routine induction and intubation, anaesthesia was maintained with 2% sevoflurane in group S and 1.5% sevoflurane/remifentanil(continuous intravenous injection at rate of 4 µg·kg(-1)·h(-1))coadministration in group SR respectively, with intermittent intravenous infusion of sulfentanil. Haemodynamic variables were collected at different time points and compared between two groups. Awaking time and extubation time, incidences of serious coughing and agitation were evaluated during emergence.Postoperative pain, nausea and cather-related bladder discomfort(CRBD)were evaluated in post anesthesia care unit. Results: Compared with group S, the arterial blood pressure and heart rate were significantly lower in group SR at extubation(all P<0.05). Time to awaking and to extubation in group SR were (4.2±2.1) min and (4.8±3.1)min respectively, in group S were (12.7±3.4) min and (15.4±4.1)min.The difference between two groups were statistically significant (t=-15.040, 14.582, all P<0.05). The incidences of serious coughing and agitation in group S were 48% and 58%, which were greater than those of group SR(6% and 10%). The difference were statistically significant(χ(2)=20.294, 23.574, all P<0.05). The NRS and incidence of complaining CRBD were similar in both groups(all P>0.05). Conclusion: Compared with sevoflurane maintenence, coadministration of remifentanil and sevoflurane maintenance regimen provides better emergence and recovery which are characterized by faster awakening and extubation with a lower incidence of emergence coughing and agitation.

[Effect of image fusion technology of radioactive particles implantation before and after the planning target and dosimetry].

Objective: To compare the post-implant target volumes and dosimetric evaluation with pre-plan, the gross tumor volume(GTV) by CT image fusion-based and the manual delineation of target volume in CT guided radioactive seeds implantation. Methods: A total of 10 patients treated under CT-guidance (125)I seed implantation during March 2016 to April 2016 were analyzed in Peking University Third Hospital.All patients underwent pre-operative CT simulation, pre-operative planning, implantation seeds, CT scanning after seed implantation and dosimetric evaluation of GTV.In every patient, post-implant target volumes were delineated by both two methods, and were divided into two groups. Group 1: image fusion pre-implantation simulation and post-operative CT image, then the contours of GTV were automatically performed by brachytherapy treatment planning system; Group 2: the contouring of the GTV on post-operative CT image were performed manually by three senior radiation oncologists independently. The average of three data was sets. Statistical analyses were performed using SPSS software, version 3.2.0. The paired t-test was used to compare the target volumes and D(90) parameters in two modality. Results: In Group 1, average volume of GTV in post-operation group was 12-167(73±56) cm(3). D(90) was 101-153 (142±19)Gy. In Group 2, they were 14-186(80±58)cm(3) and 96-146(122±16) Gy respectively. In both target volumes and D(90), there was no statistical difference between pre-operation and post-operation in Group 1.The D(90) was slightly lower than that of pre-plan group, but there was no statistical difference (P=0.142); in Group 2, between pre-operation and post-operation group, there was a significant statistical difference in the GTV (P=0.002). The difference of D(90) was similarly (P<0.01). Conclusion: The method of delineation of post-implant GTV through fusion pre-implantation simulation and post-operative CT scan images, the contours of GTV are automatically performed by brachytherapy treatment planning system appears to have improved more accuracy, reproducibility and convenience than manual delineation of target volume by maximum reduce the interference from artificial factor and metal artifacts. Further work and more cases are required in the future.

[Dosimetry verification of radioactive seed implantation with 3D printing template and CT guidance for paravertebral/retroperitoneal malignant tumor].

Objective: To compare the dose distributions of postoperative plans with preoperative plans for seeds implantations of paravertebral/retroperitoneal tumors assisted by 3D printing guide template and CT guidance, explore the effects of the technology for seeds implantations in dosimetry level and provide data support for the optimization and standardization in seeds implantation. Methods: Between December 2015 and July 2016, a total of 10 patients with paravertebral/retroperitoneal tumors (12 lesions) received 3D printing template assist radioactive seeds implantations in department of radiation oncology of Peking University Third Hospital, and included in the study. The diseases included cervical cancer, kidney cancer, abdominal stromal tumor, leiomyosarcoma of kidney, esophageal cancer and carcinoma of ureter. The prescribed doses was 110-150 Gy. All patients received preoperative planning design, individual template design and production, and the dose distribution of postoperative plan was compared with preoperative plan. Dose parameters including D(90), MPD, V(100), V(150,)conformal index(CI), EI of target volume and D(2cc) of organs at risk (spinal cord, aorta, kidney). Statistical software was SPSS 19.0 and statistical method was non-parameters Wilcoxon symbols test. Results: A total of 10 3D printing templates were designed and produced which were including 12 treatment areas.The mean D(90) of postoperative target area (GTV) was 131.1 (97.8-167.4 Gy) Gy. The actual seeds number of post operation increased by 3 to 12 in 5 cases (42.0%). The needle was well distributed. For postoperative plans, the mean D(90,)MPD, V(100,)V(150) was 131.1 Gy, 69.3 Gy, 90.2% and 65.2%, respectively, and which was 140.2 Gy, 65.6 Gy, 91.7% and 26.8%, respectively, in preoperative plans. This meant that the actual dose of target volume was slightly lower than preplanned dose, and the high dose area of target volume was larger than preplanned range, but there was no statistical difference in P value between the two groups except V(150)(P=0.004). The actual dose conformity of target volume was worse than preplanned (CI was 0.58 and 0.62, respectively) and the difference was statistically significant(P=0.019). The actual dose of external target volume was higher than preplanned (EI was 55% and 45.9%, respectively) and the difference had no significance. For organs at risk, the actual mean D(2cc) of spinal cord, aorta and kidney was 24.7, 54.4 and 29.7 Gy, respectively, which was higher than preplanned(20.6, 51.6 and 28.6 Gy, respectively), and there was no significant difference in two groups. Conclusions: Most parameters of postoperative validations for 3D printing template assisted seeds implantation in paravertebral/retroperitoneal are closed to the expectations of preoperative plans which means the improvement of accuracy in treatment.

[Calculation of the surface radial dose distribution of radioactive biliary stent loaded with 125I seeds by treatment planning system].

OBJECTIVE: To study the surface radial dose distribution of different length radioactive biliary stents in different activity of (125)I seeds by treatment planning system. METHODS: After a radioactive biliary stent was positioned in measurement phantom, which were made of solid paraffin and polymethyl methacrylate, a CT scan was performed to get the stent images. The images were then transferred to the treatment planning system for planning. The maximum dose level slice nearest to the center of the stent was selected to calculate the surface radial dose distribution. RESULTS: The length of the stents (F=3 189.160, P<0.01) and the activity of the (125)I seeds (F= 811.509, P<0.01) can both significantly affect the cumulative radial dose distribution of the radioactive stent. Radial cumulative dose dose (Gy), stent length (cm), (125)I seeds activity (mCi) and distance from the stent surface (cm) meet the regression equation: ln dose =2.565+ 0.208 length+ 1.502 activity-0.738 distance (F=4 929.279, P<0.05). CONCLUSIONS: The choice of suitable activity of radioactive (125)I should be based on treatment purpose in combination with the length and diameter of lesion and also with reference to the dose table. The measurement results are with smaller uncertainty, which can provide reference for the clinical application of dosimetry.

[CT guidance 125I seed implantation for pelvic recurrent rectal cancer assisted by 3D printing individual non-coplanar template].

Objective: To analyze the difference of dosimetric parameters between pre-plan and post-plan of 125I radioactive seed implantation assisted by 3D printing individual non-coplanar template (3D printing template) for locally recurrent rectal cancer (LRRC). Methods: From February 2016 to April 2016, a total of 10 patients with locally recurrent rectal cancer received 125I seeds implantation under CT guidance assisted by 3D printing template in Department of Radiation Oncology, Peking University Third Hospital.Each patient underwent CT simulation, three-dimentional treatment planning pre-implantation, 3D printing template design, radioactive seed implantation assisted by 3D printing template and dosimetric verification post implantation. The median activity of seed was 0.63 mCi (0.58 to 0.7 mCi) (2.15- 2.59×107 Bq), and the median number of seeds was 80 (19 to 192). D90, D100, V100, V150, CI, EI, HI, D5cc, D2cc of bladder and bowel of pre-plan and post-plan were calculated, respectively.Paired t test was used to evaluate the difference of dosimetric parameters between pre-plan and post-plan. Results: The median D90 of pre-plan and post-plan were 13 761.0 and 12 798.8 cGy, respectively.The median D100 of pre-plan and post-plan were 5 293.6 and 5 397.9 cGy, respectively.The median V100 of pre-plan and post-plan were 90.0% and 90.0%, respectively.The median V150 of pre-plan and post-plan were 63.8% and 62.4%, respectively.The median CI of pre-plan and post-plan were 0.73 and 0.67.The median EI of pre-plan and post-plan were 0.22 and 0.30, respectively. The median HI of pre-plan and post-plan were 0.29 and 0.31.The median bladder D2cc of pre-plan and post-plan were 3 088.8 and 4 240.4 cGy, respectively.The median bowel D2cc of pre-plan and post-plan were 7 051.6 and 7 903.9 cGy, respectively. Conclusions: 3D printing template might be helpful for locally recurrent rectal cancer patients who received 125I radioactive seed implantation assisted by 3D printing individual template.Seed implantation might have more chances to achieve prescription dose and dose limitation of organs at risk of pre-plan, which is important for precise implantation and quality control.

The use of targeted percutaneous laser disc decompression under the guidance of puncture-radiating pain leads to better short-term responses in lumbar disc herniation.

OBJECTIVE: Traditional percutaneous laser disc decompression (PLDD) eliminates nucleus pulposus in the center of lumbar discs. Targeted PLDD is an alternative technique that involves elimination and decompression of the target area located 5-8 mm in the front of the herniated disc. We aimed to compare the efficacy of targeted PLDD with traditional PLDD in the treatment of lumbar disc herniation and evaluate the usefulness of guidance by puncture-radiating pain on clinical outcomes of PLDD. PATIENTS AND METHODS: We treated 61 patients with lumbar disc herniation. Patients were stratified into control group, which included patients who underwent traditional PLDD, and study group in patients underwent targeted PLDD. Clinical outcomes and efficacies were evaluated at different time points using the visual analog scale (VAS) and modified MacNab criteria. RESULTS: Patients in the study group demonstrated significantly greater decreases in the VAS scores compared with those in control group. These differences were observed on Day 3, and 1 and 3 months after the treatment. Further, VAS scores were markedly lower in the patients whose treatment was guided by the puncture-radiating pain. Thus, at 1 month after the operation, 64.1% of those patients showed excellent or good outcomes based on MacNab criteria, which was almost twice the percentage seen in patients who did not experience the puncture-radiating pain (36.4%). CONCLUSIONS: Targeted PLDD is an effective, minimally invasive, and safe technique for lumbar disc herniation, and this technique achieves better short-term postsurgical outcomes than traditional PLDD. Puncture-radiating pain is an important prognostic indicator for better short-term responses to the treatment.

Total pelvic floor reconstruction versus transvaginal hysterectomy for pelvic organ prolapse: a retrospective cohort.

AIMS: To evaluate the surgical outcomes following total pelvic floor reconstruction (TPFR) and transvaginal hysterectomy (TVH). MATERIALS AND METHODS: This was a retrospective cohort study of all patients who underwent TPFR or TVH repair for pelvic organ prolapse (POP) between January 2005 and January 2011. A total of 251 consecutive women were evaluated prior to, and at two, six, and 12 months after surgery. Anatomy, symptoms, and quality of life were measured using the Pelvic Organ Prolapse Quantification system (POP-Q) and pelvic floor distress inventory (PFDI). The surgical outcomes were compared between groups using Student's t-test and ANCOVA tests (p < 0.05). RESULTS: Of the 251 patients, 129 had a total pelvic floor reconstruction (TPFR group), and concomitant modified transobturator inside-out tension-free urethral suspension (TVT-O) was used in pelvic floor dysfunction patients with stress urinary incontinence. The patients that underwent vaginal hysterectomy surgery (TVH group) were 122. At two, six, and 12 months, respectively, 12.40% (TPFR group) and 18.85% (TVH group) of the patients were lost to follow-up. There were no significant differences between TPFR group and TVH group for all preoperative variables (p > 0.05). The TPFR patients had significantly lower operation time, blood loss, anus exhaust time, remaining catheter time, and the length of stay in hospital (p < 0.05). Postoperatively, the recurrence rate in TVH group was higher than that ofTPFR group after surgery at six and 12 months (p < 0.05). The PFDI scorewas significantly different between the groups. CONCLUSIONS: The short-term clinical results suggest that the two surgeries are safe and effective in treating female POP. The patients' quality life was improved, but TPFR technique was more conspicuous for treating POP.

Different small-dose remifentanil blunting the cardiovascular response to laryngoscopy and intubation in children: a randomized double-blind comparison.

BACKGROUND: The available data provide inconsistent results on the efficacy of small-dose remifentanil attenuating the cardiovascular response to intubation in children. Therefore, this randomized double-blind study was designed to assess the ability of different small doses of remifentanil on the cardiovascular intubation response in children, with the aim of determining the optimal dose of remifentanil for this purpose. METHODS: One hundred and twenty-four children aged 3-9 yr were randomized to one of four groups to receive the following in a double-blind manner: normal saline (Group 1), remifentanil 0.75 microg kg(-1) (Group 2), remifentanil 1 microg kg(-1) (Group 3) and remifentanil 1.25 microg kg(-1) (Group 4). Non-invasive blood pressure and heart rate were recorded before anaesthesia induction (baseline value), immediately before intubation (postinduction values), at intubation and at 1 min intervals for 5 min after intubation. RESULTS: Tracheal intubation caused significant increases in systolic blood pressure and heart rate in Groups 1-3 compared with the baseline values. The maximum percent increases of systolic blood pressure and heart rate were 10% and 26% of the baseline values, respectively, in Group 2; 5% and 14% in Group 3; and 1% and 8% in Group 4 compared with 27% and 37% in Group 1. Except for the Group 3 vs. Group 4 comparison, there were significant differences among the four groups in the maximum percent increases of systolic blood pressure and heart rate. CONCLUSIONS: When used as part of anaesthesia induction with propofol and vecuronium in children, bolus administration of remifentanil resulted in a dose-related attenuation of the cardiovascular intubation response.

The circulatory responses to tracheal intubation in children: a comparison of the oral and nasal routes.

The circulatory responses to laryngoscopic tracheal intubation in 62 healthy children undergoing surgery requiring tracheal intubation were studied. They were randomly assigned to receive either the oral or nasal route for intubation. Baseline non-invasive blood pressure and heart rate were recorded following induction of anaesthesia, at intubation and then every minute for 5 min. The percentage changes of systolic blood pressure and heart rate during the measurement period were calculated. The results demonstrated that intubation time was significantly longer in the nasal group. Both oral and nasal intubation caused significant increases in blood pressure and heart rate compared to baseline and postinduction values. However, there were no significant differences found between the two groups in relation to blood pressure and heart rate. The two groups were similar with respect to the percentage changes of systolic blood pressure and heart rate during the observation period. It is concluded that oral and nasal intubation using a direct laryngoscopy can result in a similar circulatory response in anaesthetised children.

Blood pressure and heart rate changes during fibreoptic orotracheal intubation: a comparison of children and adults.

BACKGROUND AND OBJECTIVES: Autonomic circulatory regulation and airway anatomy in children are significantly different from those in adults. There is no available published data to compare whether there is a clinically relevant difference in the haemodynamic responses to fibreoptic orotracheal intubation (FOI) under the same conditions between children and adults. In this randomized clinical study, we compared the blood pressure (BP) and heart rate (HR) changes during FOI in 40 children aged 3.5-9 yr and 40 adults aged 21-57 yr, ASA 1 scheduled for elective plastic surgery under general anaesthesia requiring orotracheal intubation. METHODS: Anaesthesia was induced with intravenous (i.v.) injection of fentanyl and propofol, and face mask inhalation of isoflurane before FOI. Noninvasive BP and HR were recorded before induction (baseline values), after induction (postinduction values), at intubation and for 5 min after intubation at 1-min intervals. The percentage changes of BP and HR at each time point were calculated. RESULTS: In children and adults, HR at intubation and 1-3 min after intubation were significantly higher than baseline and postinduction values. In adults, BP at intubation increased significantly compared to the postinduction values but did not exceed baseline values. In children, BP at intubation and 1 min after intubation were significantly higher than postinduction and baseline values. As compared to adults, FOI caused a more significant pressor response in children. The percentage changes of BP at intubation and 1 min after intubation were larger in children than in adults. However, there was no significant difference in the percentage change of HR during the observation between children and adults. CONCLUSIONS: Under general anaesthesia, FOI might cause a more significant pressor response in children than in adults.

A comparative study of hemodynamic responses to orotracheal intubation with fiberoptic bronchoscope and laryngoscope in children.

BACKGROUND: The purposes of this study were to further identify the hemodynamic responses to orotracheal intubation in children, using a fiberoptic bronchoscope (FOB) and a direct laryngoscope (DLS), and to validate whether the FOB can attenuate the hemodynamic response to orotracheal intubation compared with the DLS. METHODS: Forty-three children, ASA PS I-II scheduled for elective plastic surgery under general anesthesia requiring orotracheal intubation were randomly allocated to either the DLS group (n = 20) or the FOB group (n = 23). Noninvasive systolic blood pressure (SBP) and heart rate (HR) were recorded before (baseline values) and after anesthesia induction (postinduction values), at intubation and every minute for the first 5 min after intubation. The maximal values of SBP and HR during the observation were also recorded. The product of HR and SBP [rate pressure product (RPP)] at each time point was calculated. RESULTS: In the DLS group, SBP, HR, and RPP at intubation and 1 min after intubation were significantly higher than postinduction values, but did not exceed baseline values. In the FOB group, SBP, HR, and RPP at intubation increased significantly compared with baseline and postinduction values. In the two groups, the maximal values of SBP, HR, and RPP during the observation were significantly higher than baseline values. Except for the HR at intubation, there were no significant differences in other hemodynamic parameters during the observation and the time required to reach maximal values of SBP, HR, and RPP between the two groups. CONCLUSIONS: Orotracheal intubation using FOB and DLS in children may cause similar increases in SBP and HR. Compared with the DLS, the FOB had no advantage in attenuating the hemodynamic responses to orotracheal intubation.

Blood pressure and heart rate changes during intubation: a comparison of direct laryngoscopy and a fibreoptic method.

Blood pressure and heart rate changes during nasotracheal intubation under general anaesthesia were studied in 100 patients who were randomly allocated to fibreoptic bronchoscope or direct laryngoscopy intubation. Noninvasive blood pressure and heart rate were recorded before and immediately after anaesthesia induction, at anaesthesia intubation and every minute thereafter for 5 min. Nasotracheal intubation was accompanied by significant increases in blood pressure and heart rate compared to baseline values in both groups. Blood pressure and heart rate at intubation, and the maximum values of blood pressure during the observation were significantly higher in the fibreoptic bronchoscope group. However, the maximum values of heart rate were not significantly different between the two groups. Fibreoptic nasotracheal intubation may result in more severe pressor and tachycardiac responses than direct laryngoscopic nasotracheal intubation.