The nightside cloud-top circulation of the atmosphere of Venus.

Although Venus is a terrestrial planet similar to Earth, its atmospheric circulation is much different and poorly characterized. Winds at the cloud top have been measured predominantly on the dayside. Prominent poleward drifts have been observed with dayside cloud tracking and interpreted to be caused by thermal tides and a Hadley circulation; however, the lack of nightside measurements over broad latitudes has prevented the unambiguous characterization of these components.

Validation of planning target volume margins by analyzing intrafractional localization errors for 14 prostate cancer patients based on three-dimensional cross-correlation between the prostate images of planning CT and intrafraction cone-beam CT during volumetric modulated arc therapy.

Time-averaged intreatment prostate localization errors were calculated, for the first time, by three-dimensional prostate image cross-correlation between planning CT and intrafraction kilovoltage cone-beam CT (CBCT) during volumetric modulated arc therapy (VMAT). The intrafraction CBCT volume was reconstructed by an inhouse software after acquiring cine-mode projection images during VMAT delivery. Subsequently, the margin between a clinical target volume and a planning target volume (PTV) was obtained by applying the van Herk and variant formulas using the calculated localization errors.

Individually wide range of renal motion evaluated by four-dimensional computed tomography.

Objectives: Assessment of physiologic renal motion in order to optimize abdominal intensity-modulated radiation therapy and stereotactic body radiation therapy.

Methods And Materials: Twenty patients with a median age of 47 years underwent computed tomography simulation and four-dimensional computed tomography acquisition. Thirty-nine kidneys were contoured during ten phases of respiration to estimate renal motion.