PURPOSE Low energy sources are routinely used in prostate brachytherapy. (125)I is one of the most commonly used sources. Low energy (131)Cs source was introduced recently as a brachytherapy source. The aim of this study is to compare dose distributions of (125)I, (103)Pd, and (131)Cs sources in interstitial brachytherapy of prostate. MATERIAL AND METHODS ProstaSeed (125)I brachytherapy sourc...

A method is proposed for generating dynamic wedges spanning the entire field width, defined as the collimator opening in the wedged direction, without changes to existing hardware. The technique approximates the fluence pattern of a dynamic wedge by sequentially closing the leaves of a 120-leaf multileaf collimator (MLC). Closure times for the individual leaves were derived by extending the seg...

OBJECTIVE A new dosimetric variable, dose-dropping speed (DDS), was proposed and used to evaluate normal tissue sparing among stereotactic radiosurgery (SRS) plans with different prescription isodose lines. METHODS 40 plans were generated for 8 intracranial SRS cases, prescribing to isodose levels (IDLs) ranging from 50% to 90% in 10% increments. Whilst maintaining similar coverage and confor...

Pulsed dose rate (PDR-BT) treatment is a brachytherapy modality that combines physical advantages of high-dose-rate (HDR-BT) technology (isodose optimization, radiation safety) with the radiobiological advantages of low-dose-rate (LDR-BT) brachytherapy. Pulsed brachytherapy consists of using stronger radiation source than for LDR-BT and producing series of short exposures of 10 to 30 minutes in...

Monte Carlo dose calculations will potentially reduce systematic errors that may be present in currently used dose calculation algorithms. However, Monte Carlo calculations inherently contain random errors, or statistical uncertainty, the level of which decreases inversely with the square root of computation time. Our purpose in this study was to determine the level of uncertainty at which a lu...

Radiosurgery has become an accepted treatment option for vestibular schwannomas. Nevertheless, predictors of tumor control and treatment toxicity in current radiosurgery of vestibular schwannomas are not well understood. To generate new information on predictors of tumor control and cranial nerve toxicity of single-fraction radiosurgery of vestibular schwannomas, we conducted a single-instituti...

A new randomized Phase III trial, the Japan Clinical Oncology Group (JCOG) 1408, which compares two dose fractionations (JCOG 0403 and JCOG 0702) for medically inoperable Stage IA NSCLC or small lung lesions clinically diagnosed as primary lung cancer, involves the introduction of a prescribed dose to the D95% of the planning target volume (PTV) using a superposition/convolution algorithm. Ther...

PURPOSE As a foundation for a dose escalation trial, we sought to characterize duodenal and non-duodenal small bowel organ motion between fractions of pancreatic radiation therapy. PATIENTS AND METHODS Nine patients (4 women, 5 men) undergoing radiation therapy were enrolled in this prospective study. The patients had up to four weekly CT scans performed during their course of radiation thera...

Case 1: A 14-year-old boy with nasopharyngeal cancer (T4N0M0) was treated with stereotactic radiosurgery (SRS) as a boost therapy after conventional radiotherapy. Persistent residual tumor visible with MR remained after conventional radiotherapy comprising 59.6 Gy in total. We therefore performed SRS to add a further irradiation dose while causing minimal damage to adjacent normal tissue. SRS w...

The design concept and dosimetric characteristics of a new applicator system for intraoperative radiation therapy (IORT) are presented in this work. A new hard-docking commercial system includes polymethylmethacrylate (PMMA) applicators with different diameters and applicator end angles and a set of secondary lead collimators. A telescopic device allows changing of source-to-surface distance (S...