Ruijie Yang

Percutaneous computed tomography/ultrasonography-guided permanent iodine-125 implantation as salvage therapy for recurrent squamous cell cancers of head and neck

Objective: To assess the feasibility, efficacy, and morbidity of permanent percutaneous 125I seed implantation under computed tomography (CT)/ultrasonography guidance for recurrent squamous cell carcinomas of head and neck. Methods: Twenty-five patients underwent 125I seed implantation under CT or ultrasonography guidance. Postoperative dosimetry was routinely performed for all the patients. The actuarial D90 of the implanted 125I seeds ranged from 90 Gy to 160 Gy (median: 130 Gy). The activity of 125I seed ranged from 0.35 mCi to 0.8 mCi (median: 0.6 mCi). The total number of seeds implanted ranged from 3 to 61 (median: 22). The follow-up period ranged from 3 to 40 months (median: 8 months). Results: The median local disease-free progression was 12 months (95% CI, 4.8–19.2), and the 1- and 2-year local tumor control rates were 48.7% and 39.9%, respectively. The 1- and 2-year survival rates were 42.5% and 28.3%, respectively (median: 11 months) (95% CI, 8.2–13.8). Of the 25 patients, 6 (24%) died of local recurrence and 5 (20%) died of metastases; 2 patients showed recurrences at 3 and 8 months after seed implantation and subsequently died of pneumonia. One patient died of heart disease. One developed ulceration with tumor progression. Blood vessel damage and neuropathy were not observed. Conclusion: The high local tumor control rates, minimal invasion, and low morbidity suggest that percutaneous 125I seed implantation is a feasible and safe salvage for patients with recurrent squamous cell carcinomas of the head and neck.

An investigation of 125I seed permanent implantation for recurrent carcinoma in the head and neck after surgery and external beam radiotherapy

BackgroundA preliminary assessment was conducted of the feasibility, efficacy, and morbidity of 125I seed implantation for recurrent head and neck carcinoma after surgery and external beam radiotherapy.MethodsNineteen patients with recurrent head and neck carcinomas underwent 125I seed implantation under ultrasound or computed tomography guidance. The actuarial D90 of 125I seed implantation ranged from 90 to 160 Gy (median, 131 Gy). The follow-up period ranged from 3 to 44 months (median, 11 months).ResultsThe median local control was 24 months (95% confidence interval, 10.2 to 37.8). The one- year, two-year and three-year local controls were 73.3%, 27.5% and 27.5%, respectively, whereas the one-year, two-year and three-year survival rates were 53.0%, 18.2% and 18.2%, respectively, and the median survival was 13 months (95% confidence interval, 6.6 to 19.4). A total of 26.3% of patients (5/19) died of local recurrence and 21.1% of patients (4/19) died of metastases. One suffered from a grade 1 skin reaction.Conclusions125I seed implantation is feasible and safe as a salvage treatment for patients with recurrent head and neck cancers. The high local control results and low morbidity merits further investigation.

Dosimetric Study of Cs-131, I-125, and Pd-103 Seeds for Permanent Prostate Brachytherapy

As a well-established single-modality approach for early-stage prostate cancer, transperineal interstitial permanent prostate brachytherapy (TIPPB) has gained increasing popularity due to its favorable clinical results. Currently, three isotopes, namely Cs-131, I-125, and Pd-103, are commercially available for TIPPB. This is the first study to systematically explore the dosimetric difference of these three isotopes for TIPPB. In total, 25 patients with T1-T2c prostate cancer previously implanted with I-125 seeds were randomly selected and replanned with Cs-131, I-125, and Pd-103 seeds to the prescription doses of 115, 145, and 125 Gy, respectively. The planning goals attempted were prostate V(p)100 approximately 95%, D(p)90 >or= 100%, and prostatic urethra D(u)10 <or= 150%. The dosimetric parameters, as well as the number of seeds and needles required, were analyzed and compared. The mean homogeneity index (HI) was 0.59, 0.56, and 0.46 for Cs-131, I-125, and Pd-103 plans, respectively. The average D(u)10 was 124.6%, 125.7%, and 129.7%, respectively. The average rectum V(r)100 was 0.19, 0.22, and 0.31 cc, respectively. In addition, the average number of seeds was 57.9, 63.0, and 63.7, and the average number of needles required was 31.6, 32.9, and 33.6 for Cs-131, I-125, and Pd-103 seeds, respectively. This study demonstrates that TIPPB, utilizing Cs-131 seeds, allows for better dose homogeneity, while providing comparable prostate coverage and sparing of the urethra and rectum, with a comparable number of, or fewer, seeds and needles required, compared to I-125 or Pd-103 seeds. Further biological and clinical studies associated with Cs-131 are warranted.

Interstitial 125I Seed Implantation for Cervical Lymph Node Recurrence after Multimodal Treatment of Thoracic Esophageal Squamous Cell Carcinoma

This study aimed to analysis outcome and prognosis of interstitial 125I seed implantation in patients with cervical lymph node recurrence after multimodal treatment of thoracic esophageal squamous cell carcinoma (ESCC). We conducted a retrospective review of 19 patients with 32 cervical lymph nodes recurrences after multimodal treatment (lymphadenectomy, radiotherapy, chemotherapy, and various combinations of these treatments) of thoracic ESCC, who underwent 125I seed implantation in our department from 2003 to 2011. All the patients were followed up until expiration and the median duration of follow up was 7 months (range, 3-44 months). Syndromes significantly improved after implantation. The local control rates after 3, 6, 12, and 24 months were 84.2%, 63.2%, 32.0%, and 26.0%, respectively, with a median of 10 months. The median overall survival time was 7 months (95% CI, 5.6-8.4), and 1- and 2-year survival rates were 31.6% and 10.5%, respectively. Among these patients, there were 11 died of progression of disease (PD) 3-44 months after implantation. One patient presented grade IV skin toxic effect and repaired by free flap transplantation. No fatal complications such as massive bleeding happened. In univariate analysis, N stage, number of recurrent nodes, recurrence interval time, and D90 were prognostic factors of the tumor local control and survival (p = 0.131 vs. 0.029, 0.129 vs. 0.071, 0.042 vs. 0.042, and 0.056 vs. 0.065, respectively). Multivariate analysis demonstrated that N stage, number of recurrent nodes, and recurrence interval time were independent prognostic factors of the tumor local control (p = 0.022, 0.019, and <0.001, respectively), and recurrence interval time was prognostic factor of the survival (p < 0.001). Interstitial 125I seed implantation is a safe and effective salvage treatment for cervical lymph node recurrence after multimodal treatment. The N stage, number of recurrent nodes and recurrence interval time are factors influencing tumor local control, and the recurrence interval time is independent factor influencing survival after percutaneous 125I seed implantation in ESCC with cervical lymph node recurrence.

Implementation of Incident Learning in the Safety and Quality Management of Radiotherapy: The Primary Experience in a New Established Program with Advanced Technology

Objective. To explore the implementation of incident learning for quality management of radiotherapy in a new established radiotherapy program. Materials and Methods. With reference to the consensus recommendations by American Association of Physicist in Medicine, an incident learning system was specifically established for reporting, investigating, and learning of individual incidents. The incidents that occurred in external beam radiotherapy from February, 2012, to February, 2014, were reported. Results. A total of 28 near misses and 5 incidents were reported. Among them, 5 originated in imaging for planning, 25 in planning, and 1 in plan transfer, commissioning, and delivery, respectively. One near miss/incident was classified as wrong patient, 7 wrong sites, 6 wrong laterality, and 5 wrong dose. Five reported incidents were all classified as grade 1/2 of dosimetric severity, 1 as grade 0, and the other 4 as grade 1 of medical severity. For the causes/contributory factors, negligence, policy not followed, and inadequate training contributed to 19, 15, and 12 near misses/incidents, respectively. The average incident rate per 100 patients treated was 0.4. Conclusion. Effective implementation of incident learning can reduce the occurrence of near misses/incidents and enhance the culture of safety.

Computed Tomography (CT)-guided Interstitial Permanent Implantation of 125I Seeds for Refractory Chest Wall Metastasis or Recurrence

To evaluate the efficacy and safety of 125I seeds implantation for refractory chest wall (CW) metastasis or recurrence under CT guidance. In addition we assessed initial data obtained on the therapeutic response for refractory CW metastasis or recurrence. Twenty consecutive patients underwent permanent implantation of 125I seeds (from Jul. 2004 to Jan. 2011) under computed tomography (CT) guidance. Postoperative dosimetry was routinely performed for all patients. The actuarial D90 of the implanted 125I seeds ranged from 100 Gy to 160 Gy (median: 130 Gy). The activity of 125I seeds ranged from 0.5 mCi to 0.78 mCi (median: 0.71 mCi). The total number of seeds implanted ranged from 8 to 269 (median: 53). The follow-up period ranged from 3 to 54 months (median: 11.5 months). The survival and local control probabilities were calculated by the Kaplan-Meier method. Among all the 20 patients, 3 patients had complete remission CR (15%), 12 patients had partial remission PR (60%), 5 patients had stable disease SD. The 1-, 2-, 3- and 4-year tumor control rates were all 88.7% respectively. The 1- and 2-, 3-, 4-year cancer specific survival rates were 56.5% and 47.1%, 47.1%, 47.1% respectively. The 1- and 2-, 3-, 4-year overall survival rates were 53.3% and 35.6%, 35.6%, 35.6% respectively, with a median survival of 15 months (95% CI, 7.0-22.9). Mild brachial plexus injury was seen in one patient; grade 1 or 2 skin reactions were seen in 6 patients (30%) who had received external beam radiation therapy (EBRT) before. No grade 3 and 4 skin side effects were found. Rib fracture, ulceration, pneumothorax or hemopneumothorax were not seen. Interstitial permanent implantation of 125I seeds under CT guidance is feasible, efficacious and safe for refractory CW metastasis or recurrence.

An IMRT/VMAT Technique for Nonsmall Cell Lung Cancer

The study is to investigate a Hybrid IMRT/VMAT technique which combines intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for the treatment of nonsmall cell lung cancer (NSCLC). Two partial arcs VMAT, 5-field IMRT, and hybrid plans were created for 15 patients with NSCLC. The hybrid plans were combination of 2 partial arcs VMAT and 5-field IMRT. The dose distribution of planning target volume (PTV) and organs at risk (OARs) for hybrid technique was compared with IMRT and VMAT. The monitor units (MUs) and treatment delivery time were also evaluated. Hybrid technique significantly improved the target conformity and homogeneity compared with IMRT and VMAT. The mean delivery time of IMRT, VMAT, and hybrid plans was 280 s, 114 s, and 327 s, respectively. The mean MUs needed for IMRT, VMAT, and hybrid plans were 933, 512, and 737, respectively. Hybrid technique reduced V 5, V 10, V 30, and MLD of normal lung compared with VMAT and spared the OARs better with fewer MUs with the cost of a little higher V 5, V 10, and mean lung dose (MLD) of normal lung compared with IMRT. Hybrid IMRT/VMAT can be a viable radiotherapy technique with better plan quality.

A Hybrid IMRT/VMAT Technique for the Treatment of Nasopharyngeal Cancer

Hybrid IMRT/VMAT technique which combined intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) was developed for the treatment of nasopharyngeal cancer (NPC). Two-full-arc VMAT (2ARC-VMAT), 9-field IMRT (9F-IMRT), and Hybrid IMRT/VMAT plans for NPC were compared in terms of the dosimetric quality, sparing of organs at risk (OARs), and delivery efficiency. The Hybrid IMRT/VMAT technique can improve the target dose homogeneity and conformity compared with 9F-IMRT and 2ARC-VMAT. It can reduce the dose delivered to the TMJ, mandible, temporal lobe, and unspecified tissue with fewer MUs compared with 9F-IMRT and dose delivered to parotids, brainstem, and spinal cord compared with 2ARC-VMAT technique. The mean delivery time of Hybrid plans was shorter than that of 9F-IMRT plans (408 s versus 812 s; P = 0.00) and longer than that of 2ARC-VMAT plans (408 s versus 179 s; P = 0.00). Hybrid IMRT/VMAT technique could be a viable radiotherapy technique with better plan quality.

Percutaneous Ultrasonography-Guided Permanent Iodine-125 Implantation as Salvage Therapy for Recurrent Head and Neck Carcimonas

Twenty-nine (29) patients with recurrent head and neck carcinomas underwent (125)I seed permanent implantation under ultrasonography guidance and the feasibility and efficacy of (125)I seed implantation were assessed. The postplan evaluation showed that the actuarial D90 of (125)I seeds ranged from 90 to 160 Gy (median, 130 Gy). The activity of each (125)I seed ranged from 0.35 to 0.8 mCi (median, 0.6 mCi). The total number of sources implanted ranged from 3 to 61 (median, 22). The follow-up ranged from 3 to 40 months (median, 8 months). The 1-, 2-, and 3-year local control rates were 53.1%, 34.8%, and 17.4%, respectively, with a median local control of 16 months (95% confidence interval, 5.8-26.1). The 1-, 2-, and 3- year survival rates were 54.1%, 27.5%, and 27.5%, respectively (median, 13 months; 95% confidence interval, 6.0-19.9). Of the 25 patients, 5 (17.2%) died of local recurrence and 7 (24.1%) died of metastases; 2 patients showed recurrences at 3 and 8 months after seed implantation and subsequently died of pneumonia. One (1) patient died of heart disease. One (1) developed ulceration with tumor progression. Blood vessel damage and neuropathy were not observed. Percutaneous ultrasound-guided (125)I seed implantation is a feasible, safe salvage for patients with recurrent carcinomas of the head and neck.

In vitro Dosimetric Study of Biliary Stent Loaded with Radioactive 125I Seeds

Background: A novel radioactive 125I seed-loaded biliary stent has been used for patients with malignant biliary obstruction. However, the dosimetric characteristics of the stents remain unclear. Therefore, we aimed to describe the dosimetry of the stents of different lengths — with different number as well as activities of 125I seeds. Methods: The radiation dosimetry of three representative radioactive stent models was evaluated using a treatment planning system (TPS), thermoluminescent dosimeter (TLD) measurements, and Monte Carlo (MC) simulations. In the process of TPS calculation and TLD measurement, two different water-equivalent phantoms were designed to obtain cumulative radial dose distribution. Calibration procedures using TLD in the designed phantom were also conducted. MC simulations were performed using the Monte Carlo N-Particle eXtended version 2.5 general purpose code to calculate the radioactive stents three-dimensional dose rate distribution in liquid water. Analysis of covariance was used to examine the factors influencing radial dose distribution of the radioactive stent. Results: The maximum reduction in cumulative radial dose was 26% when the seed activity changed from 0.5 mCi to 0.4 mCi for the same length of radioactive stents. The TLDs dose response in the range of 0–10 mGy irradiation by 137Cs &ggr;-ray was linear: y = 182225x − 6651.9 (R2= 0.99152; y is the irradiation dose in mGy, x is the TLDs’ reading in nC). When TLDs were irradiated by different energy radiation sources to a dose of 1 mGy, reading of TLDs was different. Doses at a distance of 0.1 cm from the three stents’ surface simulated by MC were 79, 93, and 97 Gy. Conclusions: TPS calculation, TLD measurement, and MC simulation were performed and were found to be in good agreement. Although the whole experiment was conducted in water-equivalent phantom, data in our evaluation may provide a theoretical basis for dosimetry for the clinical application.