The purpose of this study is to understand the potential for dose dumping in normal tissues (>85% of prescription dose) and to analyze effectiveness of techniques used in reducing dose dumping during IMRT. Two hundred sixty-five intensity modulated radiation therapy (IMRT) plans for 55 patients with prostate, head-and-neck (H&N), and cervix cancers with 6-MV photon beams and >5 fields were reviewed to analyze why dose dumping occurred, and the techniques used to reduce dose dumping. Various factors including gantry angles, depth of beams (100-SSD), duration of optimization, severity of dose-volume constraints (DVC) on normal structures, and spatial location of planning treatment volumes (PTV) were reviewed in relation to dose dumping.
View Article and Find Full Text PDFWe treat prostate and seminal vesicles (SV) to 45 Gy in 25 fractions (course 1) and boost prostate to 81 Gy in 20 more fractions (course 2) with Intensity Modulated Radiation Therapy (IMRT). This two-course IMRT with 45 fractions delivered a non-uniform dose to SV and required two plans and two QA procedures. We used Linear Quadratic (LQ) model to develop a single course IMRT plan to treat SV to a uniform dose, which has the same biological effective dose (BED) as that of 45 Gy in 25 fractions and prostate to 81 Gy, in 45 fractions.
View Article and Find Full Text PDFInt J Radiat Oncol Biol Phys
September 2003
Purpose: Uterine papillary serous carcinoma (UPSC) is an aggressive variant of endometrial carcinoma. The majority of patients with clinical Stage I UPSC are found to have extrauterine disease at the time of surgery. Most authors report survival rates of 35-50% for Stage I-II and 0-15% for Stage III and IV UPSC.
View Article and Find Full Text PDFBackground: It has long been recognized that many patients with locally advanced carcinoma of the cervix harbor occult paraaortic metastases. A randomized study demonstrated that elective paraaortic irradiation improved survival and reduced distant metastases. More recently, concomitant chemotherapy with pelvic irradiation has improved survival among patients with locally advanced carcinoma of the cervix.
View Article and Find Full Text PDFA dinucleotide (T-G) repeat sequence was isolated by comparing DNA from metastatic lymph node and matched normal breast samples from a ductal mammary carcinoma patient using representational difference analysis (RDA) method. Our present study used this metastasis associated DNA sequence (MADS) as a diagnostic probe to screen five patient samples by slot blot method. A new approach to isolate single cells by microdissection, namely single cell microdissection (SCM) was developed to obtain homogeneous population of tumor cells (approximately 1000) from matched primary tumors and corresponding positive lymph nodes of five patients.
View Article and Find Full Text PDFPurpose: In recent years, high-dose-rate brachytherapy has become popular in the management of carcinoma of the uterine cervix, because it eliminates many of the problems associated with low-dose-rate brachytherapy. However, the optimum time-dose-fractionation remains controversial. Two fractions of high-dose-rate brachytherapy are convenient for patients, but most radiation oncologists in the United States do not use them, because of fear that they could lead to excessive rectal or bladder toxicity.
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