Inhibition of hyperpolarization-activated cyclic nucleotide-gated cation channel attenuates cerebral ischemia reperfusion-induced impairment of learning and memory by regulating apoptotic pathway.

Stroke is the second leading cause of death globally. Cognitive dysfunction is a common complication of stroke, which seriously affects the patient's quality of life. Previous studies have shown that the expression of hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channel is closely related to ischemia-reperfusion (IR) injury and subsequent cognitive impairment. We also found that ZD7288, a specific inhibitor of the HCN channel, attenuated IR injury during short-term reperfusion. Since apoptosis can induce cell necrosis and aggravate cognitive impairment after IR, the purpose of this study is to define whether ZD7288 could improve cognitive impairment after prolonged cerebral reperfusion in rats by regulating apoptotic pathways. Our data indicated that ZD7288 can ameliorate spatial cognitive behavior and synaptic plasticity, protect the morphology of hippocampal neurons, and alleviate hippocampal apoptotic cells in IR rats. This effect may be related to down-regulating the expressions of pro-apoptotic proteins such as AIF, p53, Bax, and Caspase-3, and increasing the ratio of Bcl-2/Bax. Taken together, it suggested that inhibition of the HCN channel improves cognitive impairment after IR correlated with its regulation of apoptotic pathways.

3D-printed template and optical needle navigation in CT-guided iodine-125 permanent seed implantation.

PURPOSE: To preliminarily verify the accuracy of navigation-assisted seed implantation by comparing pre-operative and actual differences in puncture characteristics and dosimetry in computed tomography (CT)-guided, navigation-assisted radioactive iodine-125 seed implantation, using 3D-printed templates for malignant tumors' treatment. MATERIAL AND METHODS: A total of 27 tumor patients, who were treated with seed implantation under combination guidance in our hospital between December 2019 and December 2020 were enrolled in this study. Navigation needles (n = 1-3) were placed in each patient to obtain pre-operative and intra-operative puncture information, such as angle, depth, insertion point, and tip position. Moreover, dosimetry parameters in pre-operative and post-operative plans, including D90, V100, V150, V200, minimum peripheral dose (MPD), conformal index, external index, and homogeneity index of target area were investigated. RESULTS: Mean errors of the angle, depth, insertion point, and tip position were 0.5 ±0.5°, 4.0 ±2.0 mm, 1.7 ±1 mm, and 3.1 ±1.8 mm, respectively. There were no significant differences between intra-operative and pre-operative angles (p = 0.271), but there was a significant difference in the depth (p = 0.002). Errors of the angle, depth, and insertion point were larger for the pelvic/retroperitoneal area than for the head and neck/chest wall (p < 0.05). With the exception of MPD, there was no significant difference in dosimetry indices between post-operative and preoperative plans (p > 0.05). CONCLUSIONS: Seed implantation under combination guidance showed good accuracy, and the actual intra-operative puncture information and post-operative doses were in agreement with those in the pre-operative plan, thereby demonstrating promising prospects for further development.

Analysis on the accuracy of CT-guided radioactive I-125 seed implantation with 3D printing template assistance in the treatment of thoracic malignant tumors.

This article analyzes the accuracy of needle track and dose of a 3-dimensional printing template (3DPT) in the treatment of thoracic tumor with radioactive I-125 seed implantation (RISI). A total of 28 patients were included. The technical process included: (i) preoperative CT positioning, (ii) preoperative planning design, (iii) 3DPT design and printing, (iv) 3DPT alignment, (v) puncture and seed implantation. The errors of needle position and dosimetric parameters were analyzed. A total of 318 needles were used. The mean errors in needle depth, needle insertion point, needle tip and needle angle were 0.52 ± 0.48 cm, 3.4 ± 1.7 mm, 4.4 ± 2.9 mm and 2.8 ± 1.7°, respectively. The differences between actual needle insertion angle and needle depth and those designed in the preoperative were statistically significant (p < 0.05). The mean values of all the errors of the chest wall cases were smaller than those of the lungs, and the differences were statistically significant (p < 0.05). There was no significant difference between the D90 calculated in the postoperative plan and those designed in the preoperative and intraoperative plans (p > 0.05). Some dosimetric parameters of preoperative plans such as V100, V200, CI and HI were not consistent with that of preoperative plans, and the difference was statistically significant (p < 0.05). However, there were no statistical difference in the dosimetric parameters between the postoperative plans and intraoperative plans (p > 0.05). We conclude that for thoracic tumors, even under the guidance of 3DPT, there will be errors. The plan should be optimized in real time during the operation.

Long-Term Safety and Efficacy of CT-Guided I125 Radioactive Seed Implantation as a Salvage Therapy for Recurrent Head and Neck Squamous Carcinoma: A Multicenter Retrospective Study.

PURPOSE: To investigate the safety and efficacy of CT-guided I125 radioactive seed implantation (RSI) as a salvage therapy for recurrent head and neck squamous carcinoma (rHNSC) after external beam radiotherapy (EBRT) or surgery. MATERIALS AND METHODS: This is a multicenter retrospective study of 113 patients (83 males; median age 57 years) with rHNSC who underwent CT-guided I125 RSI between February 2003 and December 2017. Of the included patients, 107 patients previously received EBRT and 65 patients received surgery and all were ineligible or rejected for salvage surgery and/or repeat EBRT. RESULTS: During a median follow-up duration of 20 months (range, 3-152 months), 87 patients died. The 1-, 2-, 3-, and 5-year local control rate were 57.4%, 41.8%, 29.3%, and 15.2%, respectively. The median time to progression was 15 months [95% confidence interval (CI), 6.1-23.9 months]. The median overall survival (OS) was 20 months (95% CI, 12.4-27.6 months). The 1-, 2-, 3-, and 5-year OS rate were 63.6%, 44.6%, 29.9%, and 21.7%, respectively. Univariate and multivariate analyses revealed that KPS score and postoperative D90 were significantly associated with patients' OS. The complications were mainly grade I/II skin and mucosal reactions: 18 cases (15.9%) of grade I/II and eight cases (7.0%) of grade III radiation dermatitis, and 14 cases (12.4%) of grade I/II and three cases (2.7%) grade III mucosal reactions. No grade IV or severer complications were found. CONCLUSION: CT-guided I125 RSI may be safe as a salvage therapy for rHNSC after EBRT/surgery, yielding promising efficacy compared with historical data. KPS score and postoperative D90 may be significantly associated with OS.

Dosimetric comparison of computed tomography-guided iodine-125 seed implantation assisted with and without three-dimensional printing non-coplanar template in locally recurrent rectal cancer: a propensity score matching study.

PURPOSE: To compare post-implant dosimetric parameters of computed tomography (CT)-guided radioactive iodine-125 (125I) seed (RIS) implantation assisted with and without three-dimensional printing non-coplanar template (3D-PNCT) in locally recurrent rectal cancer (LRRC). MATERIAL AND METHODS: One hundred and fifty-five LRRC patients treated by CT-guided RIS implantation assisted with or without 3D-PNCT from October 2003 to May 2019 were included in this study. Propensity score matching (PSM) method (1 : 1) was used to adjust for differences between the 3D-group (with 3D-PNCT) and the CT-group (without 3D-PNCT). After PSM, dosimetric parameters [D90 (dose that covered 90% of target volume), D100 (dose that covered 100% of target volume), V100 (percentage of gross tumor volume (GTV) receiving 100% of prescription dose), V150 (percentage of GTV receiving 150% of prescription dose), HI (homogeneity index), CI (conformity index), and EI (external index)] of the two groups were compared. RESULTS: After PSM, 45 pairs of matched cases were selected for analysis and differences in variables between the two groups were balanced. For the 3D-group, median values of D90, D100, V100, V150, EI, and HI were 142.6 Gy (73.7-218.2 Gy), 73.7 Gy (26.2-169.3 Gy), 94.1% (74.3-100%), 71.8% (35.4-98.3%), 0.7 (0.1-30.7), and 0.20 (0-0.60), respectively, and corresponding values were 119.9 Gy (39.8-159.3 Gy), 47.0 Gy (13.0-200.9 Gy), 89.9% (38.6-100%), 62.8% (14.8-100%), 0.39 (0-11.01), and 0.30 (0-0.95), respectively, for the CT-group. Parameters including D90, D100, V100, V150, and EI in the 3D-group were significantly higher than those in the CT-group (p < 0.001, p < 0.001, p < 0.001, p < 0.001, and p = 0.006, respectively). CONCLUSIONS: 3D-PNCT can improve the accuracy of radioactive seed implantation by increasing the dose delivered to the tumor and reducing the number of "cold" spots of dose.

Accuracy and dosimetric parameters comparison of 3D-printed non-coplanar template-assisted computed tomography-guided iodine-125 seed ablative brachytherapy in pelvic lateral recurrence of gynecological carcinomas.

PURPOSE: To investigate the accuracy of needle distribution and dosimetric parameter differences of 3D-printing non-coplanar template (3D-PNCT)-assisted computed tomography (CT)-guided iodine-125 seed ablative brachytherapy (125I-SAB) in gynecological cancer patients with non-central pelvic recurrence between pre-operative plan and post-operative plan. MATERIAL AND METHODS: Thirty-eight patients with forty-one non-central pelvic recurrent gynecological carcinomas after radiotherapy were enrolled in this study. All patients received 3D-PNCT-assisted CT-guided 125I-SAB from January 2016 to January 2019. The position, angle, and depth of seed needles were measured in both pre-operative plan and intra-operative real-time plan in brachytherapy treatment planning system (B-TPS). Dosimetric parameters of D90, D100, V100, V150, and V200 as well as quality parameters of conformal index (CI), external index (EI), and homogeneity index (HI) were compared between pre-operative plan and post-operative plan. Peri-operation complications and radiation-related toxicity were assessed. RESULTS: Median follow-up time was 12 months (range, 5-34 months). Prescribed dose was 100-170 Gy (median, 120 Gy). Radioactivity of 125I seed was 0.4-0.7 mCi (median, 0.55 mCi). Mean depth deviation for 499 needles was 0.8 ±1.0 cm. Mean angular deviation was 2.2 ±2.1 degrees. Mean tip distance deviation of needles was 0.4 ±0.3 cm. There were significant differences between pre-operative and post-operative plans in CI (p = 0.001) and EI (p = 0.005). No significant differences were shown in D90, D100, V100, V150, V200, and HI between pre-operative and post-operative plans. Only few patients suffered from ≤ grade 2 toxicities. CONCLUSIONS: 3D-PNCT-assisted CT-guided 125I-SAB is safe and feasible for non-central pelvic recurrence of gynecological cancer. All complications are tolerable and mild.

The Accuracy of Individualized 3D-Printing Template-Assisted I125 Radioactive Seed Implantation for Recurrent/Metastatic Head and Neck Cancer.

PURPOSE: To evaluate the accuracy of individualized 3D-printing template-assisted I125 radioactive seed implantation (3D-PT assisted I125 RSI) for recurrent/metastatic head and neck cancer. MATERIALS AND METHODS: From February 2017 to January 2020, clinical data of 41 patients (mean age, 58.5 ± 16.1 years; 28 males) with recurrent (48.8%)/metastatic (51.2%) head and neck cancer underwent individualized 3D-PT assisted I125 RSI under CT guidance in a single institute were retrospectively reviewed. Total 430 seed needles [mean, 10.5 (range 3-17) per patient] were inserted. RESULTS: All seed needles were inserted manually in a single attempt with the technical success rate of 100% without major perioperative complications. The mean needle's entrance deviation was 0.090 cm (95% Confidence Interval, 0.081-0.098). The mean intraoperative depth and angle of the needle were consistent with that of planned (6.23 ± 0.24 vs. 6.21 ± 0.24 cm, p = 0.903; 83.14 ± 3.64 vs. 83.09 ± 3.66 degrees, p = 0.985, respectively). The mean deviation between the needle's planned and intraoperative depth and angle was 0.168 ± 0.024 cm and 1.56 ± 0.14 degrees, respectively. The postoperative dosimetry parameters, including D90, D100, V100, V150, V200, conformity index, external index, and homogeneity index, were all well-coordinated with planned dosimetry without significant difference (p = 0.515, 0.662, 0.958, 0.865, 0.872, 0.278, 0.456, and 0.989, respectively). CONCLUSIONS: Within the limitation of this study, individualized 3D-PT assisted I125 RSI may be accurate in obtaining favorable postoperative dosimetry for patients with recurrent/metastatic head and neck cancer. CLINICAL TRIAL REGISTRATION: [website], identifier [registration number].

The dosimetry evaluation of 3D printing non-coplanar template-assisted CT-guided 125I seed stereotactic ablation brachytherapy for pelvic recurrent rectal cancer after external beam radiotherapy.

The aim of this study was to investigate the safety and accuracy of computed tomography (CT)-guided 125I seed implantation assisted by a three-dimensional printing non-coplanar template (3D-PNCT) for treating pelvic locally recurrent rectal cancer (LRRC) patients. A total of 13 patients with 18 masses received 125I seed implantation. The dosimetric parameters of pre-implantation and post-implantation were calculated to evaluate the quality of 125I seed implantation. Doses delivered to the organs at risk (OAR) were also calculated. Differences between pre-implantation and post-implantation were compared by the paired t-test. The mean number of 125I seeds pre-implantation and post-implantation was 67.1 and 68.8, respectively. The mean values of D90 (dose that was delivered to 90% of the target volume), D100 (dose that was delivered to 100% of the target volume), V100 (the target volume receiving 100% of the prescription dose) and V150 (the target volume receiving 150% of the prescription dose) pre-implantation and post-implantation were 136.6 and 135.2 Gy, 63.5 and 71.0 Gy, 90.3% and 90.3% and 62.1% and 62.2%, respectively. Dosimetric outcomes were evaluated quantitatively using the dose volume indices, i.e. coverage index (CI), external volume index (EI) and relative dose homogeneity index (HI). The mean values of those indices pre-implantation and post-implantation were 0.62 and 0.61, 0.31 and 0.33, and 0.31 and 0.31, respectively. The mean doses delivered to OAR pre-implantation and post-implantation for the bladder (D2cc) and bowel (D2cc) were 33.4 and 34.4 Gy, and 58.6 and 61.8 Gy, respectively. The parameters mentioned above fitted well, and no significant difference was found among them. It is concluded that CT-guided 125I seed implantation assisted by 3D-PNCT could be a safe and accurate salvage modality for treating LRRC patients; the ideal pre-prescription dose could be achieved. Also, addition of 3D-PNCT could minimize radiation damage to the surrounding normal tissues.

The accuracy and safety of CT-guided iodine-125 seed implantation assisted by 3D non-coplanar template for retroperitoneal recurrent carcinoma.

PURPOSE: To investigate the accuracy, dosimetric parameters, and safety of 3D-printing non-coplanar template (3D-PNCT)-assisted CT guidance for radioactive iodine-125 (125I) seed implantation brachytherapy (RSI-BT) for retroperitoneal recurrent carcinomas METHODS AND MATERIALS: We enrolled 15 patients with 17 retroperitoneal recurrent carcinomas after external beam radiotherapy (EBRT). All patients received CT-guided 125I RSI-BT assisted by 3D-PNCT successfully. We compared the original needle insertion position, angular, and the needle tip distance deviations of preoperative plan with that of intraoperative in brachytherapy treatment planning system (B-TPS). The dosimetric parameters of RSI-BT were evaluated on preoperative plan, intraoperative real-time plan, and postoperative plan, including D90, D100 (the dose to 90% and 100% of the target volume), V100, V150, and V200 (the volume receives 100%, 150%, and 200% of the prescribed doses). The quality assurance of RSI-BT evaluated on conformal index (CI), external index (EI), and homogeneity index (HI) of the targets were compared among preoperative plan, intraoperative real-time plan, and postoperative plan. The perioperation complications and RSI-BT-related toxicity were assessed. RESULTS: The median follow-up was 8.2 months (range 1-18.5 months). One patient was lost to follow-up after RSI-BT. Fourteen patients were assessed for response rate and toxicity. The mean entrance point distance deviation for all 165 needles was 4.50 ± 4.10 mm (range, 0-30). The mean angular deviation was 2.70 ± 3.00° (range, 0-20). The needle tip distance deviation was 6.90 ± 6.00 mm (range, - 30-28). D90 for preoperative plan, intraoperative plan, and postoperative plan were 140.55 ± 23.93, 124.25 ± 28.04, and 128.98 ± 22.75, respectively. There was significant difference between D90 of preoperative plan with that of intraoperative plan (p = 0.036). Four lesions reached CR, six lesions reached PR, three lesions were SD, and three lesions were PD. Four patients with moderate pain became mild, and two with mild pain relieved completely after RSI-BT. The other parameters showed no differences among preoperative plan, intraoperative plan, and postoperative plan. The perioperative complications were observed in four patients, including three patients of grade 1 and one patient of grade 2. No ≥ grade 3 side effects were observed. CONCLUSION: CT-guided 125I RSI-BT assisted by 3D-PNCT was a safe, accurate, and feasible strategy for recurrent carcinomas located in the retroperitoneal regions.

The efficacy and dosimetry analysis of CT-guided 125I seed implantation assisted with 3D-printing non-co-planar template in locally recurrent rectal cancer.

BACKGROUND: Locally recurrent rectal cancer (LRRC) after surgery or external beam radiotherapy (EBRT) is a serious challenge for which no standard treatment is defined. In the present study, we investigated the feasibility of computed tomography (CT)-guided radioactive 125I seed (RIS) implantation assisted with three-dimensional printing non-coplanar template (3D-PNCT) in LRRC patients who previously received surgery or EBRT. METHODS: Sixty-six patients with LRRC treated by CT-guided RIS implantation in our institute from December 2015 to May 2019 were included. The treatment procedure included: preoperative CT localization, planning design, the printing of 3D individualized template, CT-guided RIS implantation assisted with 3D-PNCT, and postoperative dose evaluation. Therapeutic outcomes including local control (LC) and overall survival (OS) were retrospectively evaluated, as well as side effects. RESULTS: All the patients had previously received surgery or EBRT. The median follow-up time was 12.2 (range, 2.5-35.9) months. The median radioactive activity of a single RIS was 0.6 (range, 0.43-0.72) mCi. The median number of RIS was 60, ranging from 10 to 175. The dosimetric parameters included D90 (140.7 ± 33.1) Gy, D100 (90.3 ± 138.6) Gy, and V100 (91.0 ± 13.3) %. Pain relief was achieved in 85.1% (40/47) of patients. Besides, 9.1% (6/66) of patients had severe side effects (≥grade 3), including perianal skin ulcer in 1 case, fistula, radiation proctitis, and intestinal obstruction each in two cases. Median OS time was 14.7 (95% confidence interval (CI): 13.0-16.3) months, and median LC time was 12.2 (95% CI: 9.1-15.2) months. Univariate analysis revealed that when D90 > 130 Gy or D100 > 55 Gy or V100 > 90%, the LC time was remarkably prolonged. However, none of the parameters significantly affected OS. CONCLUSIONS: CT-guided RIS implantation assisted with 3D-PNCT is an effective and safe salvage treatment strategy for patients with LRRC after EBRT or surgery. D90, D100, and V100 can be used as prognostic predictors. TRIAL REGISTRATION: NCT03890926 .

Dosimetry, efficacy, and safety of three-dimensional printing noncoplanar template-assisted and CT-guided 125I seed implantation for recurrent retroperitoneal lymphatic metastasis after external beam radiotherapy.

OBJECTIVES: To evaluate the dosimetry, efficacy, and safety of radioactive 125I seed implantation (RISI) assisted by three-dimensional printing noncoplanar template (3D-PNCT) and CT for recurrent retroperitoneal lymphatic metastasis (RRLM) after previous external beam radiotherapy. METHODS AND MATERIALS: From June 2016 to August 2018, 32 patients with RRLM successfully underwent 3D-PNCT-assisted and CT-guided RISI. The dosimetry, pain relief rate, performance improvement rate, overall response rate, disease control rate, local control time (LCT), overall survival (OS), and safety profiles were evaluated. RESULTS: Dosimetric results showed that the D90, D100, V100, V150, V200, and homogeneity index were consistent in preoperation and postoperation (p > 0.05), except for the external index and conformal index (p = 0.048, p = 0.034). After RISI, 81.3% of the patients achieved pain relief, and 71.9% achieved an improvement of performance. The overall response rate and disease control rate were 85.3% and 94.1%, respectively. The LCT rates reached 66.2% and 43.2% in 1 year and two years, respectively, with a median LCT of 15.8 months. The OS rates were 74.1% and 28.1% in 1 year and two year, respectively, with a median OS reaching 17.6 months. Univariate analysis showed that when D90 > 130 Gy or D100 > 63 Gy or tumor size ≤49.8 cm3, LCT was extended significantly, but not for OS. Except for two patients developing Grade 1 retroperitoneal hematomas, no other severe adverse events were observed. CONCLUSIONS: 3D-PNCT and CT guidance provide excellent accuracy for RISI, which can be an effective and safe alternative for RRLM after external beam radiotherapy. Radiation dose and tumor size seem to significantly influence the local control.

Long-Term Outcomes and Prognostic Analysis of Computed Tomography-Guided Radioactive 125I Seed Implantation for Locally Recurrent Rectal Cancer After External Beam Radiotherapy or Surgery.

BACKGROUND: Management of locally recurrent rectal cancer (LRRC) after surgery or external beam radiotherapy (EBRT) remains a clinical challenge, given the limited treatment options and unsatisfactory outcomes. This study aimed to assess long-term outcomes of computed tomography (CT)-guided radioactive 125I seed implantation in patients with LRRC and associated prognostic factors. METHODS: A total of 101 patients with LRRC treated with CT-guided 125I seed implantation from October 2003 to April 2019 were retrospectively studied. Treatment procedures involved preoperative planning design, 125I seed implantation, and postoperative dose evaluation. We evaluated the therapeutic efficacy, adverse effects, local control (LC) time, and overall survival (OS) time. RESULTS: All the patients had previously undergone surgery or EBRT. The median age of patients was 59 (range, 31-81) years old. The median follow-up time was 20.5 (range, 0.89-125.8) months. The median LC and OS time were 10 (95% confidence interval (CI): 8.5-11.5) and 20.8 (95% CI: 18.7-22.9) months, respectively. The 1-, 2-, and 5-year LC rates were 44.2%, 20.7%, and 18.4%, respectively. The 1-, 2-, and 5-year OS rates were 73%, 31.4%, and 5%, respectively. Univariate analysis of LC suggested that when short-time tumor response achieved partial response (PR) or complete response (CR), or D90>129 Gy, or GTV ≤ 50 cm3, the LC significantly prolonged (P=0.044, 0.041, and <0.001, respectively). The multivariate analysis of LC indicated that the short-time tumor response was an independent factor influencing LC time (P<0.001). Besides, 8.9% (9/101) of the patients had adverse effects (≥grade 3): radiation-induced skin reaction (4/101), radiation-induced urinary reaction (1/101), fistula (2/101), and intestinal obstruction (2/101). The cumulative irradiation dose and the activity of a single seed were significantly correlated with adverse effects ≥grade 3 (P=0.047 and 0.035, respectively). CONCLUSION: CT-guided 125I seed implantation is a safe and effective salvage treatment for LRRC patients who previously underwent EBRT or surgery. D90 and GTV significantly influenced prognosis of such patients.

Efficacy and safety of CT-guided 125I seed implantation as a salvage treatment for locally recurrent head and neck soft tissue sarcoma after surgery and external beam radiotherapy: A 12-year study at a single institution.

OBJECTIVES: The objective of this study was to evaluate the efficacy and safety of CT-guided radioactive 125I seed implantation as a salvage treatment for locally recurrent head and neck soft tissue sarcoma (HNSTS) after surgery and external beam radiotherapy. METHODS AND MATERIALS: From December 2006 to February 2018, 25 patients with locally recurrent HNSTS after surgery and external beam radiotherapy were enrolled. All the patients successfully underwent CT-guided 125I seed implantation. The primary end points included the objective response rate (ORR) and local progression-free survival (LPFS). The secondary end points were survival (OS) and safety profiles. RESULTS: After 125I seed implantation, the ORR was 76.0%. The 1-, 3-, and 5-year LPFS rates were 65.6%, 34.4%, and 22.9%, respectively, with the median LPFS of 16.0 months. The 1-, 3-, and 5-year OS rates were 70.8%, 46.6%, and 34.0%, respectively, with the median OS of 28.0 months. Furthermore, univariate analyses showed that the recurrent T stage and histological grade were prognostic factors of LPFS, whereas only the histological grade was a predictor of OS. The major adverse events were skin/mucosal toxicities, which were generally of lower grade (≤Grade 2) and were well tolerated. CONCLUSIONS: Radioactive 125I seed implantation could be an effective and safe alternative treatment for locally recurrent HNSTS after failure of surgery and radiotherapy. Recurrent T stage and histological grade were the main factors influencing the efficacy.

Safety and efficacy of CT-guided radioactive iodine-125 seed implantation assisted by a 3D printing template for the treatment of thoracic malignancies.

OBJECTIVE: To ascertain the safety and efficacy of radioactive iodine-125 seed implantation (RISI) for the treatment of thoracic tumors. METHODS: Clinical patients with primary or metastatic tumors in the chest treated with RISI were analyzed. The RISI process included the following stages: preoperative planning, template design and 3D printing, CT-guided RISI assisted by a template, and postoperative dosimetric verification. The prescribed dose was ≥ 80 Gy. The main analytic measures were the local control (LC) rate and toxicity. RESULTS: From April 2015 to July 2018, a total of 92 patients, including 41 with lung cancer and 51 with lung metastases, were analyzed. The median lesion diameter was 5 cm. The median postoperative D90 was 142.6 Gy. The median follow-up was 10.7 months. The overall survival rates at 1 year and 3 years were 59.7% and 22.2%, respectively. The LC rates at 1 year and 3 years were 64.9% and 32.8%, respectively. The LC rates at 3 years for patients with D90 < 140 Gy and D90 > 140 Gy were 23.1% and 54.3%, respectively (P = 0.014). The LC rate of metastatic lung cancer was more favorable than that of primary lung cancer. The multivariate analyses showed that the dose and lesion type were independent factors for LC (P < 0.05). No factors were related to OS. The incidence of pneumothorax and hemoptysis was 35.8% and 3.2%, respectively. Few cases of radiotherapy-related toxicity effects were observed. CONCLUSIONS: RISI may be safe and efficacious and is associated with few complications during the treatment of thoracic tumors. If patients need local treatment and surgery or radiotherapy is not available, RISI could be considered.

Radiation-related Adverse Effects of CT-guided Implantation of 125I Seeds for Thoracic Recurrent and/or Metastatic Malignancy.

During radioactive Iodine-125 seed implantation (RISI), Iodine-125 radionuclide is implanted directly into a lesion and kills tumor cells by steadily emitting radiation. In our study, we analyzed the adverse effects of RISI for thoracic malignancy, and investigated the safety, dosage, and adverse effects of RISI for these cases. Between June 2007 and January 2018, 77 patients with thoracic recurrent and/or metastatic tumors who underwent CT-guided RISI were enrolled. Radiation-related adverse effects were analyzed, including pneumonia, esophagitis, hemorrhage, fistula, skin injury, heart injury, and spinal cord injury. We used the Common Terminology Criteria for Adverse Events (CTCAE) v4.03 to evaluate adverse effects and analyzed the relationship between adverse effects and dosimetric parameters of organs at risk (OAR), including D0.1cc, D2cc, Dmean, and V20. The results of the study were as follows: The median follow-up period was 11 months. The median postoperative dose (D90) was 122 Gy (45.7-241.8 Gy). Three patients (3.9%) showed radiation pneumonitis of grade ≥2. Two patients (2.6%) showed radiation-induced esophagitis of grade ≥2. One patient (1.3%) showed an esophageal fistula. Two patients (2.6%) had a tracheal fistula. Five patients (6.5%) had radiation-related skin reactions. One patient (1.3%) reported chest wall pain, while three (3.9%) showed hemoptysis. No patients showed radiation myelitis or cardiotoxicity. The mean D2cc of organs at risk were 165.7 Gy (lung), 10.61 Gy (esophagus), 10.25 Gy (trachea), 18.07 Gy (blood vessel), 12.64 Gy (heart), 14.77 Gy (spinal cord), 17.47 Gy (skin). Dosimetric parameters, such as D0.1cc, D2cc and Dmean, were higher in patients with toxic reactions (above the upper limit of 95% confidence interval among the overall data). Chi-square test showed that skin D0.1cc > 600 Gy, D2cc > 500 Gy, and Dmean >90 Gy were associated with grade ≥2 radiation dermatitis (p < 0.05), but no clear dose-toxicity correlation was found in other OARs. So, we concluded that the overall incidence of toxicity and adverse effects from RISI for the treatment of thoracic tumors is low. The dose-toxicity characteristics have not been fully defined. Doses within the upper limit of the 95% confidence interval may be considered safe. This was a retrospective analysis, and follow-up period was minimal, indicating possible limitations of this study.

Enhanced photothermal conversion properties of magnetic nanofluids through rotating magnetic field for direct absorption solar collector.

The direct absorption solar collector (DASCs) with nanofluids can remarkably improve the utilization efficiency of solar energy. However, in the actual applications, the temperature distribution of the receiver is extremely uneven when the concentration of nanofluids is high or the receiver is deep. This makes the temperature of upper layer much higher than that of the lower layer, resulting in much heat loss to the surrounding by convection. Here, we propose a magnetic forced convection nanofluids absorption system, where an external rotating magnetic field is used to change the heat transfer mechanism of working fluids from traditional heat conduction to the thermal convection. It is found that the photothermal conversion efficiency of FeNi/C-EG nanofluids is up to 58.1% in this system, which is 22.7% higher than non-external rotating magnetic field when the nanofluids concentration is 50 ppm. Furthermore, the agglomeration of nanofluids can be effectively reduced by an external rotating magnetic field.

Comparative study for CT-guided 125I seed implantation assisted by 3D printing coplanar and non-coplanar template in peripheral lung cancer.

PURPOSE: We compared the three-dimensional printed non-coplanar template (3DPNCT) plans with 3D-printed coplanar template (3DPCT) plans for radioactive seed implantation (RSI) in lung cancer and explored the differences between the two technologies. MATERIAL AND METHODS: 33 patients with peripheral lung cancer that received 3DPCT-assisted RSI in our department between June 2017 and February 2018 were analyzed. A 3DPNCT plan was re-designed for all patients. The prescribed dose and seed activity in the new plan were the same as the 3DPCT plan. The data in the two plans were compared, including seed number, needle number, number of needles needed to cross the ribs, and dosimetry parameters. Dosimetry parameters included D90, Dmean, MPD (minimum peripheral dose), V100, V150, CI (conformity index), EI (external index), HI (homogeneity index) of target volume, D2cc of spinal cord and aorta, and V20 of affected side lung. We used a paired t-test and two groups of related non-parameters tests to examine statistical significance. A p value < 0.05 was considered statistically significant. RESULTS: We found no significant difference in dosimetry parameters (p > 0.05), except MPD. The mean MPD of the 3DPNCT plan was significantly higher than the 3DPCT plan (88.5 Gy and 81.8 Gy, respectively, p = 0.017). The number of needles used in the 3DPNCT plan and the number of needles needed to cross the ribs were significantly less compared with the 3DPCT plan (p = 0.000). CONCLUSIONS: The dose distributions of the two 3DPCT plans were similar. 3DPNCT plan had a higher dose in target volume margin, with fewer needles and fewer breaks to the ribs.

The Effectiveness and Prognostic Factors of CT-Guided Radioactive I-125 Seed Implantation for the Treatment of Recurrent Head and Neck Cancer After External Beam Radiation Therapy.

PURPOSE: To analyze the efficacy and safety of radioactive I-125 seed implantation in the treatment of recurrent head and neck tumors after radiation therapy. METHODS AND MATERIALS: The data of 101 patients with recurrent head and neck cancer after radiation therapy who received computed tomography guided radioactive I-125 seed implantation were analyzed. The median previous cumulative external irradiation dose was 66 Gy, and the median dose to 90% of the target volume (D90) after operation was 117 Gy. The short-term efficacy was evaluated by Response Evaluation Criteria in Solid Tumors version 1.1, and the adverse event was evaluated by Common Terminology Criteria for Adverse Events version 4.0. RESULTS: The 5-year local control rate was 26.6%, and the 5-year overall survival rate was 15.5%. Univariate analysis showed that factors related to local control rate included age, pathologic type, implantation site, lesion volume, and D90. The 5-year local control rate was 11.5% (2-year) if D90 was <120 Gy and 44.2% if D90 was ≥120 Gy (P = .001). Multivariate analysis showed that pathologic type, lesion volume, and D90 were independent factors related to local control (P = .002, 0, .014, respectively); Karnofsky performance status and lesion volume were independent factors associated with survival (P = .021 and 0, respectively). For the side effects, there were 26 cases of skin or mucosa ulceration (25.7%), 14 cases of pain (13.9%), and 2 cases of dry mouth (2%). The correlation between toxicity and dose had not been found. CONCLUSIONS: Radioactive I-125 seed implantation in the treatment of recurrent head and neck cancer after radiation therapy showed acceptable efficacy and safety. Nonsquamous carcinoma, small lesion volume, and high dose (D90) were correlated with better local control.

Side effects of CT-guided implantation of 125I seeds for recurrent malignant tumors of the head and neck assisted by 3D printing non co-planar template.

BACKGROUND: For the recurrence of head and neck cancer after operation and radiotherapy, the local control of radioactive seed implantation is good, and it has a certain palliative effect. This study aims to investigate the acute and late side effects of a three-dimentional printing non co-planar template (3D-PNCT) for computed tomography (CT)-guided radioactive 125I seed (RIS) implantation in recurrent cancer of the head and neck. METHODS: Between January 2016 and December 2016, forty-two patients with local recurrent malignant tumors of the head and neck received 3D-PNCT-assisted RIS implantation. The prescribed dose was 110-160 Gy. Preoperative planning design, production of individual guide plates, RIS implantation, postoperative dose evaluation, and follow-up were completed for all patients. Side effects in the skin, mucous membranes, blood and spinal cord were evaluated. RESULTS: All patients underwent surgery successfully. Duration of follow-up was 4-14 (median, of 8.5) months. The activity of a single RIS was 0.34-0.7 (median, 0.6) mCi. The number of RIS was 10-126 (median, 34). The number of implantation needles was 4-31 (median, 11). The mean D2cc (dose to the most exposed 2-cc volume) and D0.1cc (dose to the most exposed 0.1-cc volume) of the skin were 24.9 (7.1-85.5) and 47.5 (9.4-167.2), respectively, whereas those of the spinal cord were 8.4 (4.5-33.3) and 14.2 (13.6-63.0), mucosa were 35.1 (4.2-82.8) and 87.0 (6.6-214.1), parotid glands were 16.2 (12.8-19.7) and 29.8 (26.1-33.4) and those of the trachea were 17.9 (2.5-45.9) and 32.7 (3.9-83.9), respectively. No case had an acute reaction of grade ≥ 3. Three cases had a grade-1 skin reaction. Blood toxicity did not occur, nor spinal-cord injury. Xerostomia was not aggravated than that of before brachytherapy. One case had a grade-3 nerve response. CONCLUSIONS: 3D-PNCT-assisted RIS implantation can provide good accuracy for positioning. For local recurrent malignant tumor of head and neck, there were no obvious adverse reactions.

Dosimetry Verification of 125I Seeds Implantation With Three-Dimensional Printing Noncoplanar Templates and CT Guidance for Paravertebral/Retroperitoneal Malignant Tumors.

OBJECTIVE: To compare dose distributions of postoperative plans with preoperative plans for radioactive seed implantation of paravertebral/retroperitoneal tumors assisted by 3-dimensional printing noncoplanar templates and computed tomography. METHODS: Sixteen patients with paravertebral/retroperitoneal tumors (21 lesions) underwent radioactive seed implantation with 3-dimensional printing noncoplanar templates. Prescribed dose was 110 to 160 Gy. We compared the dose distribution of the postoperative plan with the preoperative plan. Dose parameters were D90, minimum peripheral dose, V100, V150, conformal index and external index of the target volume, and the dose received by 2 cm3 of normal tissue of organs at risk (spinal cord, aorta, and kidney). RESULTS: Sixteen 3-dimensional printing noncoplanar templates were produced for 21 treatment areas. Mean gross tumor volume (preoperative) of patients was 61.1 cm3, mean needle number was 17, mean number of implanted 125I seeds was 65, and mean D90 of postoperative target area (gross tumor volume) was 131.1 Gy. Actual number of seeds postbrachytherapy increased by 1 to 12 in 8 cases. For postoperative plans, the mean D90, minimum peripheral dose, V100, V150 was 131.1 Gy, 67.1 Gy, 90.2%, and 64.1%, respectively, and 135.0 Gy, 64.7 Gy, 90.9%, and 64.1%, respectively, in preoperative plans. Comparing with the preplanned cases, the dose of the target volume was slightly lower and the high-dose area of the target volume was larger in postoperative cases, but the difference was not statistically significant (P > .05). Actual dose conformity of the target volume was lower than preplanned, and the difference was statistically significant (P = .005). CONCLUSION: Three-dimensional printing noncoplanar templates can provide good accuracy for positioning and direction in radioactive seed implantation.