No abstract available.
Biosensing Techniques ; Urinary Bladder

Geant4 (GEometry ANd Tracking) provides various packages specialized in modeling electromagnetic interactions. The validation of Geant4 physics models is a significant issue for the applications of Geant4 based simulation in medical physics. The purpose of this study is to evaluate accuracy of Geant4 electromagnetic physics for proton therapy. The validation was performed both the Continuous slowing down approximation (CSDA) range and the stopping power. In each test, the reliability of the electromagnetic models in a selected group of materials was evaluated such as water, bone, adipose tissue and various atomic elements. Results of Geant4 simulation were compared with the National Institute of Standards and Technology (NIST) reference data. As results of comparison about water, bone and adipose tissue, average percent difference of CSDA range were presented 1.0%, 1.4% and 1.4%, respectively. Average percent difference of stopping power were presented 0.7%, 1.0% and 1.3%, respectively. The data were analyzed through the kolmogorov-smirnov Goodness-of-Fit statistical analysis test. All the results from electromagnetic models showed a good agreement with the reference data, where all the corresponding p-values are higher than the confidence level alpha=0.05 set.
Adipose Tissue ; Magnets ; Proton Therapy ; Protons ; Water

In proton therapy, the analysis of secondary particles is important due to delivered dose outside the target volume and thus increased potential risk for the development of secondary cancer. The purpose of this study is to analyze the influence of secondary particles from proton beams on fluence and energy deposition in the presence of inhomogeneous material by using Geant4 simulation toolkit. The inhomogeneity was modeled with the condition that the adipose tissue, bone and lung equivalent slab with thickness of 2 cm were inserted at 30% (Plateau region) and 80% (Bragg peak region) dose points of maximum dose in Bragg curve. The energy of proton was varied with 100, 130, 160 and 190 MeV for energy dependency. The results for secondary particles were presented for the fluence and deposited energy of secondary particles at inhomogeneous condition. Our study demonstrates that the fluence of secondary particles is neither influenced insertion of inhomogeneties nor the energy of initial proton, while there is a little effect by material density. The deposited energy of secondary particles has a difference in the position placed inhomogeneous materials. In the Plateau region, deposited energy of secondary particles mostly depends on the density of inserted materials. Deposited energy in the Bragg region, in otherwise, is influenced by both density of inserted material and initial energy of proton beams. Our results suggest a possibility of prediction about the distribution of secondary particles within complex heterogeneity.
Adipose Tissue ; Dependency (Psychology) ; Lung ; Population Characteristics ; Proton Therapy ; Protons

PURPOSE: Neoadjuvant chemotherapy (NC) is yet to be established as the definitive treatment regimen for locally advanced breast cancer (LABC). The aim of this study was to determine the efficacy and toxicity of NC with epirubicin and paclitaxel. METHODS: Between March 2007 and January 2009, 50 patients with LABC were enrolled in an open-label, phase II, multicenter study carried out at five distinct institutions. All patients were scheduled to receive four cycles of 60 mg/m2 epirubicin and 175 mg/m2 paclitaxel every 3 weeks, preoperatively, unless they developed profound side effects or disease progression. After curative surgery, two additional cycles of chemotherapy were administered to patients who had shown a positive response to NC. RESULTS: In all, 196 cycles of chemotherapy were administered preoperatively; 47 of the 50 patients (94%) underwent all four cycles of designated treatment. Complete disappearance of invasive foci of the primary tumor, and negative axillary lymph nodes were confirmed in eight patients (16.0%), post operation. The cumulative 5-year disease-free survival rate was 70.0% for patients with complete remission (CR) and partial remission (PR), and 33.3% for patients with stable disease (SD) and progressive disease (PD) (p=0.018). The cumulative 5-year overall survival was 90.0% for patients who achieved CR and PR and 55.6% for patients who had SD and PD (p=0.001). Neutropenia (42.0%) was the most common grade 3/4 toxicity. However, none of the toxicities resulted in cessation of the treatment. CONCLUSION: The encouraging pathologic response observed in the patients treated with epirubicin plus paclitaxel NC in this study suggests that epirubicin could be a substitute for doxorubicin, which is the most cardiotoxic agent.
Breast Neoplasms* ; Disease Progression ; Disease-Free Survival ; Doxorubicin ; Drug Therapy* ; Epirubicin* ; Humans ; Lymph Nodes ; Neoadjuvant Therapy ; Neutropenia ; Paclitaxel

BACKGROUND: Lung cancer is the leading cause of cancer deaths in Korea and the number of lung cancer deaths is increasing. The higher response rates, decreased toxicity and improved performance status of the first-line treatments have resulted in an increased number of patients becoming candidates for second-line therapy. Several new anti??neoplastic agents, including gemcitabine, docetaxel and paclitaxel, have recently demonstrated second-line activity. This phase II study evaluated the efficacy and toxicity of gemcitabine and vinorelbine as combination chemotherapy for Korean patients with NSCLC as a second-line treatment. METHODS: Sixty response-evaluable patients were enrolled from December 2000 to July 2003. We conducted a phase II study of a combination gemcitabine and vinorelbine chemotherapy for patients with histologically confirmed NSCLC that was stage IIIB and IV disease at the time of diagnosis, and the disease had progressed onward or the patients had relapsed after first-line platinum-based chemotherapy. They were treated with intravenous gemcitabine 1000mg/m2 and intravenous vinorelbine 25mg/m2 on days 1 and 8. This chemotherapy regimen was repeated every 3 weeks. RESULTS: A total of 215 cycles of treatment were given and the mean number of cycles was 3.6 cycles. All the patients were evaluable for the toxicity profile. The response rate was 10% according to the WHO criteria.?The median progression free survival was 3.8 months and the median survival time was 10.1 months. The 1-year survival rate was 32.9%. Grade III and IV neutropenia were seen in 20 (33.3%) and 7 (11.7%) patients, respectively. CONCLUSION: The combination of gemcitabine and vinorelbine is active and well tolerated as a second-line therapy for patients with advanced nonsmall cell lung carcinoma.
Carcinoma, Non-Small-Cell Lung ; Diagnosis ; Disease-Free Survival ; Drug Therapy ; Drug Therapy, Combination* ; Humans ; Korea ; Lung Neoplasms ; Lung* ; Neutropenia ; Paclitaxel ; Survival Rate