intravitreal injection is the most common approach for drug delivery to the posterior segment in humans. however, following the injection, drugs are rapidly eliminated from the vitreous, with half-lives up to a few days. depending on the rate of clearance from the vitreous, large boluses and frequent administrations may be required to ensure therapeutic levels over an extended period of time. m...

objective (s): transdermal preparations for testosterone are becoming popular because of their unique advantages such as avoidance of first-pass effect, convenience, improved bioavailability, and reduction of systemic side effects. a novel testosterone transdermal delivery system (tdds) was developed using a palm oil base called hamintm (a commercial product) and tested using in vitro and in vi...

The post-linac energy collimation system of CLIC is designed to fulfil an essential function of protection of the Beam Delivery System (BDS) against miss-steered beams generated by failure modes in the main linac. Guaranteeing the collimator survivability in case of direct beam impact is very challenging, if we take into account the need to deal with an unprecedented transverse energy density p...

Introduction: The success of radiotherapy cancer treatment delivery depends on the accuracy of patient positioning for each treatment session. A number of kilovoltage x-ray volumetric imaging modalities with an additional source and detector have been developed to allow patient set-up verification based on the internal anatomy, but a significant portion of medical linacs are on...

PURPOSE By default, the 4-mm wide leaf-pairs of the Elekta Beam Modulator MLC not used for field shaping are moved to under the primary collimator to minimize the leakage dose. The trade-off is the increased beam delivery time in the case of IMRT. This study examines the dosimetric impact and improved delivery efficiency by allowing the unused leaf-pair as 2mm gap to stay within the PTV apertur...

In the TESLA Linear Collider feedback systems will provide an orbit correction within the bunch train. To limit the reduction in the targeted luminosity of 3:1 10 cm s 1 due to beam separations to less than a few percent, the collisions have to be vertically stabilized within a fraction of the beam spot size of 5 nm. One system, located in the beam delivery system (BDS), is used to correct vert...

The stability of delivery of low monitor unit (MU) setting is important especially for step-andshoot intensity-modulated radiotherapy (IMRT), because the nature of the technique is inherent to repeat beam on/off according to the number of the segments. This study evaluates the dose linearity and profile flatness/symmetry under low MU settings for Vero4DRT, a new linear-accelerator based irradia...

background: physical wedges are still widely used as beam modifiers in external beam radiotherapy. however the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems. the aim of this study is to investigate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value l...