Objective To investigate clinical outcomes and side effects of 103Pd seed brachytherapy for malignant tumors. Methods Twenty patients with residual or recurrent unresectable malignancies were treated with 103Pd seed implantation under the guidance of ultrasonigraphy or CT scans. Three patients were given a local anesthesia and 17 patients, general anesthesia. The match peripheral doses ranged from 97.3 Gy to 182.78 Gy (mean, 123 Gy). The activity of each seed ranged from 1.4 mCi to 1.8 mCi. The planning target volume (PTV) included a 1 cm isotropic expansion margin around the clinical target volume (CTV). The seeds were retrogradely placed with a Mick applicator. External beam radiation was required 3～4 weeks after seed implantation in 6 patients, with a total dose of 45～50 Gy and 2 Gy each fraction. All of the patients received CT scanning after implantation for quality evaluation and underwent routine chest X-ray examination at 24～48 hours for seed observation. Results A complete response was achieved in 5 patients and a partial response in 12 patients. Two patients were assessed as having stable disease. In 1 patient with prostatic cancer, the serum PSA level was decreased significantly. The local control rate was 90% (18/20). The 20 patients were followed for 2～25 months (median,11 months).Two patients were lost to follow-up at 6 and 12 months after operation, respectively. Twelve patients died and 6 patients survived.No severe complications were recorded postoperatively. Conclusions 103Pd brachytherapy for malignant tumors gives a high local control rate and satisfactory reliability.

Objective To investigate the technological feasibility and short-term efficacy of 125I seeds implantation in head and neck cancer. Methods Thirty patients with head and neck recurrent cancer were treated with 125I seeds interstitial brachytherapy. The operation was performed under local anesthesia and the 125I seeds were implanted under the guidance of ultrasonography. The seed needles were implanted parallelly to each other, at 1～1.5 cm apart. The Mick applicator was used to implant seed at 1 cm interval. The radioactive activity per seed ranged 0.40～0.70 mCi, and the matched peripheral dose (MPD) was 90～160 Gy. The number of 125I seed implanted per lesion was 3～84 (median, 24). Ten patients with a seed radioactive dose

Objective To analyze the application and funding for projects in radiation oncology from National Natural Science Foundation of China ( NNSFC ) from 2006 to 2015. Methods To collect the funding information in radiation oncology from NNSFC from 2006 to 2015, a computerized search was performed in the ISIS system using a subject code of H1610 and a keyword of radiation oncology. Analyses were performed in distribution of research fields, the geographical distribution of applicants, and the properties of institutes/universities the applicants were affiliated with. Results In the last decade, a total of 435 projects in the field of radiation oncology were funded with 180 million yuan. Most projects were funded by general, youth, and regional foundation, which covered the highest proportion of NNSFC. For a single project, the amounts of funding from general, youth, and regional foundations were 530, 220, and 400 thousand yuan, respectively. The institutes/universities the NNSFC?funded projects were affiliated with were located quite close to each other. The top 10 institutes/universities in terms of the number of NNSFC?funded projects covered 53% of projects. In all projects, 88% studied basic science, which covered many hot topics in oncology including biological effects of radiotherapy, microenvironment, and stem cells. A small number ( 12%) of projects focused on physics. Top 3 cancers in terms of the number of projects and the amount of funding were lung cancer, nasopharyngeal carcinoma, and esophagus cancer. Conclusions In the last decade, the field of radiation oncology has stable increases in the number of NNSFC?funded projects and the amount of funding. The NNSFC?funded research teams are unevenly distributed, most of which are located in East China. The most popular topic in basic science studies is about biological effects of radiotherapy.

Objective To summarize the efficacy and the feasibility of 125I seed implantation for recurrence cervical lymph node of head and neck tumor after radiotherapy or radiotherapy plus neck dissection. Methods Thirty-six patients with the recurrence cervical lymphnode of head and neck tumor after radiotherapy (17 patients) or radiotherapy plus neck dissection (19 patients) were treated with 125I seed implantation guided by ultrasound or CT under local anesthesia. The median number of seeds was 27( range from 3 to 78 ). Postoperative quality evaluation were routinely obtained for all patients. The actuarial D90 ranged from 90-160 Gy (median, 130 Gy). Results The follow-up rate was 100%. The number of the patients who were followed up over 1-and 2-year were 11 and 3. The overall response rate was 81%. The 1-and 2-year over local control rates, over survival rates were 69% and 35%, 50% and 22%, respectively.The 1-and 2-year local control rates in patients with recurrence node after radiotherapy plus neck dissection were 72% and 54%, while those were 67% and 50% in patients with recurrence node after radiotherapy,respectively (χ2=00,P=0.965). The 1-and 2-year survival rates in two groups were 48%, 13% , and 51%, 39%, respectively (χ2=0.17, P=0.676). Conclusions 125I seed implantation is a safe,minimal invasive with low morbidity and high efficacy salvage treatment method for cervical lymph node recurrence of head and neck tumor after radiotherapy with or without neck dissection.

Objective To retrospectively study the efficacy and side-effect of 125I seed implantation combined with endocrinal therapy in stage T3N0M0 prostate cancer.Methods The study included 22 patients with clinical stage T3 N0 M0 prostate cancer who were treated with transperineal 125I seed implantation guided by transrectal ultrasound,real time TPS and endocrinal therapy.The minimum peripheral doses (MPD) were 140-160 Gy.The median number of seeds was 74(26-90).The activity of each seed was 1.55 × 107 (1.30 × 107-1.85 × 107) Bq.11 patients were treated with orchidectomy,and 11 patients were treated with androgen deprivation therapy.Results All 22 patients completed the seed implantation successfully.The 5-year biochemical progression-free survival was 70.6％,and 5-year overall survival was 81.8％.2 patients were found biochemical failure in 12 months after seed implantation,and another 1 patient failed in 90 months.Endocrinal therapy was followed thereafter.After the seed implantation,the urinary complications of grade 1 and 2 were 54.5％ and 9.1％ respectively,and the rectum side-effect of grade 1 and 2 were 22.7％ and 9.1％.1 patient suffered rectal complication of grade 4.Conclusions Good effect and tolerance are observed in prostate cancer patients of stage T3N0M0 receiving 125I seed implantation plus endocrinal therapy.The treatment can be considered for those who refuse to receive external beam radiotherapy.

Objective To investigate the mechanism of radiosensitization by cetuximab (C225) on human tongue cancer Tca8113 cell line in vitro.Methods Tca8113 cell line with and without C225 treatment received 6 MV X-ray irradiation of different doses (0, 2,4,6, 8 and 10 Gy). Cell proliferation,cell-cycle distribution and clonogenic survival were analyzed through cell counting,MTT,colony formation assay,and flow cytometry,respectively.Results After irradiation of different doses,the growth inhibition rates in C225 group were higher than control (t =- 15.6 - -3.0,P＜0.05),the radiobiological parameters (D0,Dq,N,and SF2 ) in C225 group were lower than control so that SER of C225 group was 1.353,and the proportions of G0/G1 cells in C225 group were higher than control ( t =-7.64,-7.89,-4.78,P ＜0.05 ) at 4,6,8 Gy.When the irradiation doses increased,the early phase apoptosis in both groups increased at first and then decreased with the maximum difference at 4 Gy [(7.96±0.36)％ in C225 group and (4.13 ±0.29)％ in control group,t =-12.75,P＜0.01 ].Conclusions C225 has radiosensitization effect on Tca8113 cell line,possible through Go/G1 arrest and induction of apoptosia.

Objective:To explore the accuracy of CT-guided 125I seed implantation assisted by a navigation system and 3D-printing template in the treatment of recurrent malignant pelvic tumors by comparing pre-plan and intraoperative physical dosimetric parameters. Methods:This study involved 15 patients with recurrent malignant pelvic tumors who received CT-guided radioactive 125I seed implantation assisted by a navigation system and 3D-printing template in the Peking University Third Hospital from Dec 2018 to Feb 2020.Seven of the patients had cervical cancers, seven had rectal cancers, and one had prostate cancer.The median age was 55 years (34-84 years old). The prescription dose was 100-150 Gy.The pre-plan and post-implant data were compared, including the number of implanted seeds, implantation needle number, and some dosimetric parameters such as the minimum prescription doses delivered to 90% and 100% of target volume( D90, D100), mean percentages of volume receiving 100%, 150%, and 200% of the prescription doses( V100, V150, and V200), conformity index(CI), external index(EI), and homogeneity index(HI)of the target volume. Results:The median lesion volume was 29.20 cm 3, the median seed number was 54, and the median D90 was 150 Gy.The post-implant V150 was lower than pre-plan V150 (64.1% vs. 67.1%, t=2.937, P=0.011), and the post-implant mean HI was higher than pre-plan HI (32.01% vs. 26.68%, t=-2.950, P=0.011). There were no significant differences in other dosimetric parameters before and after seed implantation. Conclusions:With CT-guided radioactive seed implantation assisted by a navigation system and 3D-printing template in the treatment of recurrent malignant pelvic tumors, the actual postoperative dose could meet the preoperative plan requirement, ensuring the accuracy and consistency of the dose delivered.

As an interstitial brachytherapy,radioactive seed implantation could provide high doses in the local site and minimal doses at surrounding normal tissues.It has become one of the best choice for early stage prostate carcinoma.Radioactive seeds were implanted under the guidance by ultrasound,CT and MRI,featured with surgical and interventional treatment.Based on dosimetry for target and organs at risk,radioactive seed implantation is multiple disciplinary.In order to acquire the accurate and high quality seed implantation,it is necessary to set up a team including surgeons,radiation oncologists,interventional doctors and nuclear medicine doctors.The content of the consensus is as follows:radiation physics and dosimetry,indications,side-effects and 3 D-printing template work-follow.Despite the benefit of radioactive seed implantation for solid carcinoma,there still a compelling need for prospective randomized and stage Ⅲ clinical trials from multiple centers,so as to upgrade the evidencebased level,above all confirm the role of radioactive seed implantation in the comprehensive treatment of tumors.

Objective To investigate the inhibition effect of continuous low dose rate radiation by 125Ⅰ radioactive seeds on Hep-2 cells and the corresponding mechanisms.Methods Hep-2 cells were divided into three groups,control group,single dose radiation group with high dose rate form X-rays (SDR) and continuous low dose rate radiation by 125Ⅰ seeds group (125Ⅰ-CLDR).After exposure to SDR and 125Ⅰ-CLDR,colony formation assay was used to determine the radiosensitivity and RBE,trypan blue exclusion assay was used to determine cell proliferation,and flow cytometry was used to detect cell apoptosis and cell cycle arrest.Results The radiosensitivity of Hep-2 cells to 125Ⅰ-CLDR was higher than that to SDR.The RBE of 125Ⅰ-CLDR versus SDR was approximately 1.61.The α/β ratio of 125Ⅰ-CLDR group was higher than that of SDR group.Both SDR and 125Ⅰ-CLDR inhibited cell proliferation (t =30.9,40.7,P＜0.05),in which 125Ⅰ-CLDR was stronger than SDR (t =9.8,P＜0.05).In addition,the incidences of apoptosis and G2/M arrest induced by125Ⅰ-CLDR were also stronger than those induced by SDR (t =5.8,19.8,P ＜ 0.05).Conclusions 125Ⅰ-CLDR generates more serious inhibition effects than SDR on reducing cellular DNA repair capacity,inducing cell apoptosis and G2/M arrest and inhibiting proliferation of Hep-2 cells.

Objective To evaluate the efficacy and adverse reactions of CT-guided 125I radioactive seed implantation in treatment of locally recurrent rectal cancer (LRRC).Methods Thirty patients with LRRC who refused operation or were unable to endure pelvic radiotherapy received 125I seed implantation under CT guidance.Three-dimensional treatment planning system was used to calculate the number,activity,and dose of the seeds needed.The activity of seeds ranged from 14.8 to 29.6 MBq with a median of 25.9 MBq,the seed numbers ranged from 33 to 137 with a median of 74.5,the prescription doses ranged from120-160 Gy,and the actual verification dose D90 ranged from 75.91 to 159.32 Gy with a median of 119.77 Gy.Dosimetric verification by CT scanning was conducted immediately after the treatment.Follow-up was conducted for 15.2 months(4.2-35.0 months).Results The follow-up rate was 93.3％.The pain relief rate was 95.2％.The overall response rate was 50.0％,including a complete response rate of 13.3％ and a partial response rate of 36.7％.The 1-and 2-year local control rates were 30.0％ and 8.0％ respectively.The median local control survival time was 7.8 month.The 1-and 2-year survival rates were 66.5％ and 32.9％ respectively.The median overall survival time was 21.5 months.Complications,mainly adverse effects of skin and urinary system (frequent urination,urgent urination,and dysuria) occurred in 6 patients with a rate of 20.0％.Conclusions Minimally invasive and with satisfying efficacy and tolerable complications,CT-guided 125I radioactive seed implantation is a favorable option for treatment of LRRC,especially for the patients who have undergone previous pelvic radiation.