T cells recognize foreign antigens in association with the highly polymorphic class I and class II molecules encoded in the major histocompatibility complex (MHC). In addition to these highly polymorphic molecules, the murine MHC also encodes, in the Qa/Tla region, several less polymorphic structures referred to as class I-like or class Ib molecules. Although no specific function has been assig...

The purpose of this study is to evaluate the use of the Dosimetry Check system for patient-specific IMRT QA. Typical QA methods measure the dose in an array dosimeter surrounded by homogenous medium for which the treatment plan has been recomputed. With the Dosimetry Check system, fluence measurements acquired on a portal dosimeter is applied to the patient's CT scans. Instead of making dose co...

BACKGROUND To investigate the sensitivity of various gamma criteria used in the gamma-index method for patient-specific volumetric modulated arc therapy (VMAT) quality assurance (QA) for stereotactic body radiation therapy (SBRT) using a flattening filter free (FFF) photon beam. METHODS Three types of intentional misalignments were introduced to original high-definition multi-leaf collimator ...

The health-promoting hospitals (HPH) movement in Estonia was initiated in 1999. This study aimed to compare the implementation of health-promoting and quality-related activities in HPH and those which have not joined the HPH network (non-HPH). In the beginning of 2005, a postal survey was conducted among the top managers of 54 Estonian hospitals. The questionnaire was based on the WHO standards...

A respiratory training system based on audiovisual biofeedback has been implemented at our institution. It is intended to improve patients' respiratory regularity during four-dimensional (4D) computed tomography (CT) image acquisition. The purpose is to help eliminate the artifacts in 4D-CT images caused by irregular breathing, as well as improve delivery efficiency during treatment, where resp...

The increasing popularity of intensity-modulated arc therapy (IMAT) treatments requires specifically designed linac quality assurance (QA) programs. Gantry angle is one of the parameters that has a major effect on the outcome of IMAT treatments since dose reconstruction for patient-specific QA relies on the gantry angle; therefore, it is essential to ensure its accuracy for correct delivery of ...

Current therapies to treat autoimmune disease focus mainly on downstream targets of autoimmune responses, including effector cells and cytokines. A potentially more effective approach would entail targeting autoreactive T cells that initiate the disease cascade and break self tolerance. The murine MHC class Ib molecule Qa-1b (HLA-E in humans) exhibits limited polymorphisms and binds to 2 domina...

We investigated the sensitivity of the gamma index to two factors: the spatial resolution and the noise level in the measured dose distribution. We also examined how the choice of reference distribution and analysis software affect the sensitivity of gamma analysis to these two factors for quality assurance (QA) of intensity-modulated radiation therapy (IMRT) treatment plans. For ten clinical I...

Owners of imaging modalities using ionising radiation should have a documented quality assurance (QA) program, as well as methods to justify new radiological procedures to ensure safe operation and adequate clinical image quality. This includes having a system for correcting divergences, written imaging protocols, assessment of patient and staff absorbed doses and a documented education and tra...

A Varian Portal Dosimetry system was compared to an isocentrically mounted MapCHECK 2 diode array for volumetric modulated arc therapy (VMAT) QA. A Varian TrueBeam STx with an aS-1000 digital imaging panel was used to acquire VMAT QA images for 13 plans using four photon energies (6, 8, 10 and 15 MV). The EPID-based QA images were compared to the Portal Dose Image Prediction calculated in the V...