3D dose reconstruction for narrow beams using ion chamber array measurements.

3D dose reconstruction is a verification of the delivered absorbed dose. Our aim was to describe and evaluate a 3D dose reconstruction method applied to phantoms in the context of narrow beams. A solid water phantom and a phantom containing a bone-equivalent material were irradiated on a 6 MV linac. The transmitted dose was measured by using one array of a 2D ion chamber detector. The dose reconstruction was obtained by an iterative algorithm. A phantom set-up error and organ interfraction motion were simulated to test the algorithm sensitivity. In all configurations convergence was obtained within three iterations. A local reconstructed dose agreement of at least 3% / 3mm with respect to the planned dose was obtained, except in a few points of the penumbra. The reconstructed primary fluences were consistent with the planned ones, which validates the whole reconstruction process. The results validate our method in a simple geometry and for narrow beams. The method is sensitive to a set-up error of a heterogeneous phantom and interfraction heterogeneous organ motion.

Ätiologie und Management der Gicht [The etiology and management of gout].

Gout is an inflammatory arthritis caused by monosodium urate (MSU) crystal deposits in and around the joint. The formation of urinary calculi can also occur in gout, but are less common than arthritis. Gout usually presents with recurrent episodes of joint inflammation, which over time lead to tophus formation and joint destruction. In the last decade, significant advances have been made regarding not only the epidemiology and genetics of gout and hyperuricemia but also the mechanisms of inflammation and treatment of gout. In addition, knowledge concerning the key role of interleukin 1 (IL-1) has provided new therapeutic perspectives. However, the current management of gout is often suboptimal, with many Patienten either not receiving adequate treatment or being unable to tolerate existing treatments. New therapeutic agents provide interesting new options for Patienten with difficult-to-treat gouty arthritis.The English full-text version of this is available at SpringerLink (under "Supplemental").