60-year-old woman was treated for a brain metastasis. The patient received intensity-modulated radiation therapy (SIB-IMRT) dose of 30 Gy for the whole brain and 40 Gy delivered simultaneously to individual brain metastases in 10 fractions. The present report investigated the influence of applied novel prepared treatment plan, among others the fractionation protocol on the electroencephalogram ...

BACKGROUND This study investigated and quantified the dosimetric impact of the distance from the tumor to the spinal cord and fractionation schemes for patients who received stereotactic body radiation therapy (SBRT) and hypofractionated simultaneous integrated boost (HF-SIB). MATERIAL AND METHODS Six modified planning target volumes (PTVs) for 5 patients with spinal metastases were created by ...

OBJECTIVES We aimed to increase the bacterial cell killing efficacy of erythrosine-mediated photodynamic therapy (PDT) of Streptococcus mutans biofilms by fractionating the delivered light dose into a series of shorter pulses. METHODS S. mutans biofilms of 200 microm thickness were grown in a constant-depth film fermenter (CDFF). Biofilms were incubated with 22 microM erythrosine before being...

In this thesis, we investigate the improvement in treatment effectiveness when dynamically optimizing the fractionation scheme in radiation therapy. In the first part of the thesis, we consider delivering a different dose each day depending on the observed patient anatomy. Given that a fixed prescribed dose must be delivered to the tumor over the course of the treatment, such an approach result...

Background: Ionizing radiation causes cognitive impairment in adult brain. However, the effects of various irradiation protocols with fractionated fixed total dose on hippocampal function have not yet been studied. Materials and Methods: Fractionated whole brain irradiation with a total dose of 36 Gy was performed according to the following protocols: 2Gy-18 fractions (2Gy*18), 4Gy-9 fraction (...

T reatment of large and bulky malignant tumors remains a challenge for oncologists. As tumor size increases the ability of most modalities including conventional external beam radiation to control the tumor decreases. The decrease in normal tissue tolerance with increasing volume of tissue irradiated restricts the escalation of total radiation dose by conventional external beam approaches. Alte...

The tool most commonly used for quantitative predictions of dose/fractionation dependencies in radiotherapy is the mechanistically based linear-quadratic (LQ) model. The LQ formalism is now almost universally used for calculating radiotherapeutic isoeffect doses for different fractionation/protraction schemes. In summary, the LQ model has the following useful properties for predicting isoeffect...

OBJECTIVE Radiation effects induced in non-irradiated cells are termed radiation-induced bystander effects (RIBE). The present study intends to examine the RIBE response of QU-DB bystander cells to first, second and third radiation fractions and compare their cumulative outcome with an equal, single acute dose. MATERIALS AND METHODS This experimental study irradiated three groups of target ce...

Early laryngeal, especially glottic, cancer is a good candidate for radiotherapy because obvious early symptoms (e.g. hoarseness) make earlier treatment possible and with highly successful localized control. This type of cancer is also a good model for exploring the basic principles of radiation oncology and several key findings (e.g. dose, fractionation, field size, patient fixation, and overa...

AIMS The Royal College of Radiologists has published a review of the evidence base for radiotherapy dose fractionation. We modelled the implications of changes in practice on radiotherapy demand and compared it with current activity, access and waiting times across the countries of the UK. MATERIALS AND METHODS We collected data on diagnosis, dose fractionation and waiting times on all patien...