The dose distributions for a patient with cancer involving the sternum were calculated for both a kilovoltage x-ray beam and a megavoltage electron beam. The minimum target dose and dose uniformity over the target volume were significantly better using electrons (90%-101%) than kilovoltage x-rays (68%-119%). The calculated lung dose and integral patient dose were also less for electrons than ki...

Megavoltage X-ray sources are commonly used for therapy planning, and knowledge of their spectral distribution is important for accurate dose calculations. There are many methods that could provide reasonable estimations of Megavoltage X-ray spectra, when very accurate attenuation data or at least very good set of initial guesses of the spectra are available. We present here a novel method, whi...

one of the applications of gold nanoparticles (gnps) in medicine is radiation dose-enhancing effect. although there are many simulations, in vitro and in vivo evidence that gnps can enhance significantly the radiation dose effect of orthovoltage beams. these beams compared with megavoltage (mv) beams, have limited applications in radiotherapy. in order to evaluate gnps radiosensitization perfor...

Ophthalmic Graves' disease and histiocytosis X involving the orbit are occasionally refractory to treatment, so that vision may be threatened. In these situations megavoltage external beam radiotherapy should be employed, and the indications for this treatment are discussed. A highly accurate technique is described, using precise planning with information obtained from high definition CT scans,...

It has been thought that adult nervous tissues show a remarkable degree of resistance to injury by x rays. Clemedson and Nelson (1960), after a comprehensive review of the literature, state: " Nervous tissues, especially of adult animals, show a remarkable radio-resistance." In the past few years, however, experimental work on animals (Lander, 1959; Innes and Carsten, 1961) suggests that delaye...

Background: The in vitro studies show that the modern cardiac pacemakers utilising the complementary metal-oxide semi-conductor (CMOS) circuitry can be adversely affected by therapeutic radiation. However, the published clinical data are sparse regarding the safety of radiotherapy delivery to patients with artificial pacemakers. Despite the potential risk of life threatening complications, ther...

We present a case of cervical cancer treated by concurrent chemoradiation. In radiation therapy part, the combination of the whole pelvic helical tomotherapy plus image-guided brachytherapy with megavoltage computed tomography of helical tomotherapy was performed. We propose this therapeutic approach could be considered in a curative setting in some problematic situation as our institution.

Successful delivery of conformal fields requires stringent immobilization and treatment verification, as well as knowledge of the setup reproducibility. [1] Before coming OBI, electronic portal imaging detector was used to detect the setup errors. EPID images are not clear vision to identify correctly and immediately because they were produced by megavoltage X-ray during treatment setup. In OBI...