Biomedical subjects

Cheng-I Hsieh

Publications and source records attributed to Cheng-I Hsieh.

6 recordsLinked to original sources

PubMed2006

A prognostic scoring system for locoregional control in nasopharyngeal carcinoma following conformal radiotherapy.

PURPOSE: This study established a prognostic scoring system for nasopharyngeal carcinoma (NPC), which estimates the probability of locoregional (LR) control following definitive conformal radiotherapy. METHODS AND MATERIALS: Patients with nondisseminated NPC at initial presentation (n = 630) were enrolled in this study. All patients had magnetic resonance imaging of the head and neck and were treated with conformal radiotherapy. Among them, 93% had concurrent chemotherapy, and 76% had postradiation chemotherapy. The extent of the primary tumor, age at diagnosis, primary tumor size, tumor and nodal classification, histology, and serum lactate dehydrogenase (LDH) level before treatment were included in the analysis for building a prognostic scoring system. The end point for this study was LR control. RESULTS: The prognostic score was defined as the number of adverse prognostic factors present at diagnosis. Four factors had similarly independent prognostic effects (hazard ratio, 2.0-2.6): age >40 years, histologic WHO type I-II, serum LDH level > or =410 U/L, and involvement of two or more sites of the following anatomic structures, i.e., sphenoid floor, clivus marrow, clivus cortex, prevertebral muscles, and petrous bone. The score predicted the 5-year probability of LR control as follows: 0 (15% of the patients), 100%; 1 (42% of the patients), 93%; 2 (29% of the patients), 83%; 3 or higher (13% of the patients), 71%. CONCLUSION: This scoring system is useful in the decision-making for individual patients and the design of clinical trials to improve LR control for advanced-stage NPC.

Adult↗

PubMed2005

Extended-field radiotherapy and high-dose-rate brachytherapy with concurrent and adjuvant cisplatin-based chemotherapy for locally advanced cervical cancer: a phase I/II study.

OBJECTIVE: The purpose of this prospective study was to investigate the toxicity and efficacy of integrating extended-field para-aortic and pelvic external radiation, high-dose-rate intracavity brachytherapy, and concurrent and adjuvant cisplatin-based chemotherapy for locally advanced cervical cancer. METHOD: A phase I/II study was performed from 1998 to 2003 including sixty-three patients with both clinical FIGO and MRI/CT-based TNM stage IIB-IVA cervical cancer. Patients were treated with extended-field external radiation to the para-aortic and pelvic regions with 45 Gy in 25 fractions, and an additional boost to the gross nodes to 50.4 Gy and the parametrium to 59.4 Gy. Patients also received a high-dose-rate (HDR) intracavity brachytherapy with doses of 22-31 Gy to point A in 4-6 fractions. Concurrently, two cycles of cisplatin (50-80 mg/m(2)) were administered in weeks 1 and 5 during radiotherapy, as well as two cycles of cisplatin (60-80 mg/m(2)) for 1 day and 5-fluorouracil (600-800 mg/m(2)) for 4 days at 1 and 2 months after completion of radiotherapy. The treatment-related acute and late side effects were evaluated using RTOG criteria, and the disease control and survival rate were calculated using the Kaplan-Meier method. The median follow-up interval was 36 months. RESULTS: All sixty-three patients completed the planned extended-field radiotherapy and high-dose-rate brachytherapy with 2 concurrent cycles of cisplatin. Fifty-eight (92%) patients received 2 cycles of the post-radiation adjuvant chemotherapy of cisplatin and 5-fluorouracil. RTOG grade III acute toxicity was gastrointestinal (2%) and hematological (10%). No patient had grade IV acute toxicity. Late grades III-IV morbidity actuarial risk of 6% at 6.5 years primarily involved the injuries to the bowels requiring surgical intervention for intestinal obstruction or fistula formation. Initial sites of recurrence were locoregional failure alone (pelvic and para-aortic regions within the radiation field), 3%; distant metastases only, 8%; and locoregional failure plus distant metastases, 8%. The observed rates at 3-year and 5-year of locoregional control, freedom from distant metastasis, and overall survival were 86% and 86%, 81% and 81%, and 81% and 77%, respectively. CONCLUSION: Incorporating HDR brachytherapy into a regimen including concurrent chemotherapy and extended radiation appears safe and effective.

Adult↗

PubMed2004

Removal of copper (II) by manganese-coated sand in a liquid fluidized-bed reactor.

This study was performed in a fluidized-bed reactor (FBR) filled with manganese-coated sand (MCS) to treat copper-contaminated wastewater. The adsorption characteristics of MCS, the adsorption equilibrium of MCS, and the copper removal capacity by MCS in FBR were investigated. In terms of the adsorption characteristics of MCS, the surface of MCS was evaluated using a scanning electron microscope (SEM). Energy dispersive analysis (EDS) of X-rays indicated the composition of MCS, and the quantity of manganese on MCS was determined by means of acid digestion analysis. The experimental results indicated that copper was removed by both sorption (ion exchange and adsorption) and coprecipitation on the surface of MCS in FBR. Copper removal efficiency was highly dependent on the pH and increased with increasing pH from pH 2 to 8. After the copper adsorption by MCS, the pH in solution was decreased. When the MCS concentration was greater than 10 g/l, the copper adsorptivities obtained by FBR were almost the same as that from the shaker and when the MCS concentration reached 40 g/l, the copper adsorptivity in FBR was greater than that from the shaker. The adsorption sites of MCS could be used efficiently by the FBR. A Langmuir adsorption isotherm equation fit the measured adsorption data from the batch equilibrium adsorption test better than the Freundlich adsorption isotherm equation did. In addition, the adsorption rate increased when the influent wastewater was aerated.

Adsorption↗

PubMed2004

Removal of Cu(II) from aqueous solution in a fluidized-bed reactor.

In this study, a fluidized-bed reactor (FBR) was employed to treat copper-containing wastewater by mean of copper precipitation on the surface of sand grains. The conditions for optimum copper removal efficiency were also investigated. This technology was controlled so as to keep supersaturation low to induce the nucleated precipitation of copper coating on the sand surface in an FBR. The effects of relevant parameters, such as the pH value, the molar ratio of [C(T)] to [Cu(2+)], hydraulic loading and the types of chemical reagents used, were examined. The experimental results indicated that 96% copper removal efficiency could be achieved when the influent copper concentration was 10mg l(-1). The optimum chemical reagent was Na(2)CO(3); the molar ratio of [C(T)]/[Cu(2+)] was 2, and the optimal hydraulic loading was not be more than 25m h(-1). In addition, preventing homogeneous nucleation in the FBR was an important operation parameter. Homogeneous nucleation and molecular growth would lead to undesirable microparticle formation in the effluent. A good mixture of carbonate and copper in the presence of sand grains could reduce the level of homogeneous nucleation in the bottom of the reactor. Energy dispersive analysis (EDS) of X-rays provided insight into the copper coating on the sand surface, and element analysis indicated the weight percentages of CuCO(3) and Cu(OH)(2) in precipitate.

Carbonates↗

PubMed2002

Improvement of local control of T3 and T4 nasopharyngeal carcinoma by hyperfractionated radiotherapy and concomitant chemotherapy.

PURPOSE: When the primary tumor of nasopharyngeal carcinoma (NPC) is treated at the base of skull and intracranium with conventional radiotherapy, the result is generally poor. In this report, we investigated whether hyperfractionated radiotherapy (HFRT) and concomitant chemotherapy (CCT) could achieve better local control and survival in NPC patients with T3 and T4 lesions. PATIENTS AND METHODS: Forty-eight patients (11 T3 and 37 T4 NPC) were treated with HFRT and CCT. HFRT was administered at 1.2 Gy per fraction, two fractions per day, Monday-Friday for 62 fractions for a total dose of 74.4 Gy. Concomitant chemotherapy consisting of cis-diamino-dichloroplatinum (CDDP) alone or CDDP and 5-fluorouracil was delivered simultaneously with radiotherapy during Weeks 1 and 6. Adjuvant chemotherapy consisted of CDDP and 5-fluorouracil for 2 to 3 cycles and was given monthly beginning 1 month after completion of radiation. RESULTS: With a median follow-up of 57 months (range: 28-94 months), the 3-year locoregional control rate was 93%, the disease-free survival rate was 71%, and the overall survival rate was 72%. For T4 patients, the 3-year locoregional control rate was 91%, disease-free survival was 62%, and overall survival was 63%. The major acute toxicity was Grade 3 mucositis in 73% and Grade 2 weight loss in 31% of patients. Fifty percent of patients were tube fed. Most patients tolerated the combined modality treatments relatively well; 88% of patients completed their radiation treatment within 8 weeks. CONCLUSION: HFRT and CCT for T3 and T4 NPC were associated with excellent local control and improved survival. The treatment-related toxicity was acceptable and reversible. We would recommend using HFRT with CCT for advanced T-stage NPC if the three-dimensional conformal radiation planning shows a significant portion of the brainstem to be inside the treatment field.

Adult↗

PubMed2002

Time of flight diffraction imaging for double-probe technique.

Due to rapid progress in microelectronics and computer technologies, the system evolving from analog to digital, and a programmable and flexible synthetic aperture focusing technique (SAFT) for the single-probe pulse-echo imaging technique of ultrasonic nondestructive testing (NDT) becomes feasible. The double-probe reflection technique usually is used to detect the nonhorizontal flaws in the ultrasonic NDT. Because there is an offset between the transmitter and receiver, the position and size of the flaw cannot be directly read from the image. Therefore, a digital signal processing (DSP) imaging method is proposed to process the ultrasonic image obtained by double-probe reflection technique. In the imaging, the signal is redistributed on an ellipsoid with the transmitter and receiver positions as focuses, and the traveltime sum for the echo from the ellipsoid to the focuses as the traveltime of signal. After redistributing all the signals, the useful signals can be constructively added in some point in which the reflected point is; otherwise, the signals will be destructively added. Therefore, the image resolution of the flaw can be improved and the position and size of the flaw can be estimated directly from the processed image. Based on the experimental results, the steep flaw (45 degrees) cannot be detected by the pulse echo technique but can be detected by the double-probe method, and the double-probe B-scan image of 30 degrees tilted crack is clearer than the pulse echo B-scan image. However, the flaw image departs from its true position greatly. After processing, the steep flaw image can be moved to its true position. When the flaws are not greater than the probe largely, the sizes of the flaws are difficult to be discriminated in both pulse echo and double-probe B-scan images. In the processed double-probe B-scan image, the size of the flaws can be estimated successfully, and the images of the flaws are close to their true shape.

Journal Article↗