background: this prospective study was conducted to evaluate and compare the efficacies of nasopharyngoscopy and ct scan in the diagnosis of local failure of external beam radiotherapy (ebrt) for nasopharyngeal carcinoma. methods: total 52 patients of histopathologically proven nasopharyngeal carcinoma treated with external beam radiotherapy (ebrt), were included in this study. for every patien...

A retrospective study was undertaken to examine the thyroid cancer cases referred for external radiotherapy to our department during the period of 1991-99. Within this period, a total of 33 patients had been treated by irradiation for thyroid cancer or its metastases and these cases were evaluated for age, sex, pathology and type of surgery. The reason of patients’ referral for external r...

For the first time in their history, the 2 medical organizations most responsible for the treatment of prostate cancer in the United States—the American Society for Radiation Oncology (ASTRO) and the American Urological Association (AUA)—have issued a joint guideline, a series of 9 major statements on the use of radiation therapy (either adjuvant or salvage) after prostatectomy. The statements ...

There are radiobiological rationales supporting hypofractionated radiotherapy for prostate cancer. The recent advancements in treatment planning and delivery allow sophisticated radiation treatments to take advantage of the differences in radiobiology of prostate cancer and the surrounding normal tissues. The preliminary results from clinical studies indicate that abbreviated fractionation prog...

"Biological optimization" (BIOP) means planning treatments using (radio)biological criteria and models, that is, tumour control probability and normal-tissue complication probability. Four different levels of BIOP are identified: Level I is "isotoxic" individualization of prescription dose D(presc) at fixed fraction number. D(presc) is varied to keep the NTCP of the organ at risk constant. Sign...

Since the inception of radiotherapy soon after the discovery of X rays by Roentgen in 1895, the technology of X ray production has first been aimed towards ever higher photon and electron beam energies and intensities, and more recently towards computerization and intensity modulated beam delivery. During the first 50 years of radiotherapy the technological progress was relatively slow and main...

PURPOSE To determine the clinical and dosimetric factors that predict prostate-specific antygen (PSA) bouncing following brachytherapy HDR and three-dimensional conformal radiation therapy (3D-CRT) for prostate cancer patients. MATERIAL AND METHODS The evaluated population consisted of 121 prostate cancer patients with a minimum of 5 years of follow-up and at least 6 post-treatment PSA levels...

BACKGROUND AND PURPOSE We verified the propriety of our systematic error reduction strategy by means of a computer simulation based on our data of position error with a prone fixation device for prostate IMRT. MATERIALS AND METHODS Computer simulations of the off-line correction method for systematic setup errors based on the portal imaging taken on the first several days of the treatment ses...