objectives: the aim of this study was to verify the treatment planning systems (tpss). the next aim was to validate imsure qa software for patient-specific qa in radiotherapy clinics.  material and methods: we used imsure qa software (standard imaging, v 3.5) for verification of 92 non-imrt plans (540 fields) in 10 radiotherapy clinics. to validate the imsure, dose measurement was performed in ...

background: stereotactic radiosurgery is an important clinical tool for the treatment of small lesions in the brain, including benign conditions, malignant and localized metastatic tumors. a dosimetry study was performed for elekta ‘synergy s ’ as a dedicated stereotactic radiosurgery unit, capable of generating circular radiation fields with diameters of 1-5 cm at isocentre using the beam/egs4...

background: radiotherapy treatment planning requires different dosimetric quantities as input in order to calculate a desired dose distribution. this study has been focused to evaluate the depth dose characteristics of superficial x-rays being used for radiotherapy treatment. materials and methods: computerized 3-d water phantom of multi-data system was used. the measurements were made through ...

introduction dosimetric accuracy is a major issue in the quality assurance (qa) program for treatment planning systems (tps). an important contribution to this process has been a proper dosimetry method to guarantee the accuracy of delivered dose to the tumor. in brachytherapy (bt) of gynecological (gyn) cancer it is usual to insert a combination of tandem and ovoid applicators with a complicat...

background: radiotherapy plays an important role in the management of most malignant and many benign primary central nervous system (cns) tumors. radiotherapy affects both tumor cells and uninvolved normal cells; so, it is important to estimate absorbed dose to organs at risk in this kind of treatment. the aim of this study was to determine the absorbed dose to chiasma, lens, optic nerve, retin...

This study evaluates reliability of current technology for measurement of renal arterial blood flow by breath-held velocity-encoded MRI. Overall accuracy was determined by comparing MRI measurements with known flow in controlled-flow-loop phantom studies. Measurements using prospective and retrospective gating methods were compared in phantom studies with pulsatile flow, not revealing significa...

OBJECTIVES To evaluate the accuracy of magnetic resonance imaging measurements of cartilage tissue-mimicking phantoms and to determine a combination of magnetic resonance imaging parameters to optimize accuracy while minimizing scan time. METHOD Edge dimensions from 4 rectangular agar phantoms ranging from 10.5 to 14.5 mm in length and 1.25 to 5.5 mm in width were independently measured by tw...

Electrical impedance tomography (EIT) uses body surface electrical stimulation and measurements to create conductivity images; it shows promise as a non-invasive technology to monitor the distribution of lung ventilation. Most applications of EIT have placed electrodes in a 2D ring around the thorax, and thus produced 2D cross-sectional images. These images are unable to distinguish out-of-plan...

PURPOSE Volumetric modulated arc therapy (RapidArc; Varian Medical Systems, Palo Alto, CA) allows fast delivery of stereotactic radiotherapy for Stage I lung tumors. We investigated discrepancies between the calculated and delivered dose distributions, as well as the dosimetric impact of leaf interplay with breathing-induced tumor motion. METHODS AND MATERIALS In 20 consecutive patients with ...

PURPOSE To prospectively assess in a phantom the reconstruction errors and detection limits of cartilage thickness measurements obtained with multidetector computed tomographic (CT) arthrography, as a function of contrast agent concentration, scanning direction, spatial resolution, joint spacing, and tube current, with known measurements as the reference standard. MATERIALS AND METHODS A phan...