Randomized self-controlled study comparing open-face vs. closed immobilization masks in fractionated cranial radiotherapy.

Purpose: To compare patient discomfort and immobilisation performance of open-face and closed immobilization masks in cranial radiotherapy.

Material And Methods: This was a single-center randomized self-controlled clinical trial. At CT simulation, an open-face and closed mask was made for each patient and treatment plans with identical dose prescription were generated for each mask.

Comparison of beam segment versus full plan re-optimization in daily magnetic resonance imaging-guided online-adaptive radiotherapy.

The optimal approach for magnetic resonance imaging-guided online adaptive radiotherapy is currently unknown and needs to consider patient on-couch time constraints. The aim of this study was to compare two different plan optimization approaches. The comparison was performed in 238 clinically applied online-adapted treatment plans from 55 patients, in which the approach of re-optimization was selected based on the physician's choice.

Distance to isocenter is not associated with an increased risk for local failure in LINAC-based single-isocenter SRS or SRT for multiple brain metastases.

Purpose: To evaluate the impact of the distance between treatment isocenter and brain metastases on local failure in patients treated with a frameless linear-accelerator-based single-isocenter volumetric modulated arc (VMAT) SRS/SRT for multiple brain metastases.

Methods And Materials: Patients treated with SRT for brain metastases (BM) between April 2014 and May 2019 were included in this retrospective study. BM treated with a single-isocenter multiple-target (SIMT) SRT were evaluated for local recurrence-free intervals in dependency to their distance to the treatment isocenter.

Dosimetric and geometric end-to-end accuracy of a magnetic resonance guided linear accelerator.

The introduction of real-time imaging by magnetic resonance guided linear accelerators (MR-Linacs) enabled adaptive treatments and gating on the tumor position. Different end-to-end tests monitored the accuracy of our MR-Linac during the first year of clinical operation. We report on the stability of these tests covering a static, adaptive and gating workflow.

Treatment plan quality during online adaptive re-planning.

Background: Online adaptive radiotherapy is intended to prevent plan degradation caused by inter-fractional tumor volume and shape changes, but time limitations make online re-planning challenging. The aim of this study was to compare the quality of online-adapted plans to their respective reference treatment plans.

Methods: Fifty-two patients treated on a ViewRay MRIdian Linac were included in this retrospective study.

Effect of the positron range of 18F, 68Ga and 124I on PET/CT in lung-equivalent materials.

Purpose: The aim of this study was to investigate the effect of positron range on visualization and quantification in (18)F, (68)Ga and (124)I positron emission tomography (PET)/CT of lung-like tissue.

Methods: Different sources were measured in air, in lung-equivalent foams and in water, using a clinical PET/CT and a microPET system. Intensity profiles and curves with the cumulative number of annihilations were derived and numerically characterized.

Comparison of sentinel gamma probes for 99mTc breast cancer surgery based on NEMA NU3-2004 standard.

Purpose: Hand-held gamma-probes are used for the identification of the sentinel node location during intra-operative radio-guided surgeries. Various gamma-probes, which use different detectors, collimation and electronics, are available on the market. Spatial resolution, sensitivity and angular resolution of the probes are believed to be determinant for the success of the identification of the sentinel node during radiosurgery.

Identification of a shine-through artifact in the trachea with (124)I PET/CT.

Unlabelled: The presence of (124)I in tissue near the trachea can cause a phenomenon that might be called shine-through. The effect is due to high-energy positrons that cross the air-filled trachea and annihilate at the opposite tracheal wall, incorrectly suggesting uptake at that location.

Methods: We investigated shine-through using (124)I, (68)Ga, and (18)F PET/CT scans of a neck phantom.

Dopamine release in human ventral striatum and expectation of reward.

Using the ability of [11C]raclopride to compete with dopamine for D(2)/D(3) receptors, we investigated by positron emission tomography the effect of placebo (saline) injection on dopamine release in the ventral striatum of patients with Parkinson's disease. We found evidence for placebo-induced dopamine release of similar magnitude to that reported in healthy volunteers after amphetamine administration. However, in contrast to the dorsal striatum, there were no differences in [11C]raclopride binding potential changes between patients who experienced the reward (those who reported placebo-induced clinical benefit) and those who did not.