Set-up skin markings are performed, in several centers, for radiotherapy (RT) treatments. This study aimed to compare two permanent methods: lancets and an electric marking pen, the Comfort Marker 2.0® (CM). This was a prospective, unicentric, randomized study. Patients aged 18 years or older referred to our department to receive RT were recruited. Patients were randomly assigned, in a 1:1 ratio, to receive set-up markings using lancets or CM. The markings arrangement followed our departmental protocols. The coprimary endpoints were patients' comfort and effectiveness. Secondary endpoints included radiation therapists (RTTs) satisfaction and cosmesis. Between October 2021 and January 2022, 100 patients were enrolled (50 received lancets and 50 CM) and assessed for the comfort and satisfaction outcomes. CM was significantly less painful than the lancets, with 44% and 16% of the patients, respectively, considering the tattooing process painless (RR = 2.75; 95% IC: 1.36 - 5.58). On the RTT-reported satisfaction, CM had significantly easier processes than lancets (98.0% vs. 78.0%, respectively; RR = 1.26; 95% CI: 1.08 - 1.46). For effectiveness and cosmesis assessment, 98 patients were analyzed (48 received lancets and 50 CM). Patients receiving CM had a significantly higher proportion of markings graded as good and excellent compared to those receiving lancets (98.0% and 50.0%, respectively, had ≥75% of the tattoos assessed as good/excellent, RR = 1.96; 95% CI: 1.47 - 2.61). On the cosmetic evaluation, patients receiving CM had significantly better cosmetic markings, with a median score of 4.4 (vs. 3.5 for lancets, p <0.001). The trial results demonstrated that tattooing with the CM is significantly less painful, more effective, easier to apply, and cosmetically superior to tattooing with lancets. Tattooing with CM allows for better results regarding pain, quality, ease and cosmesis.

To directly address the important issue of MRI geometric distortions in stereotactic radiosurgery (SRS) planning, we performed a phantom study of sequence acquisition optimization. This study analyzed, in particular, the effects of clinically relevant gadolinium (Gd) concentration as filling solution for the phantom, as well as phase encoding reversal direction and flip angle on distortion. We created a rigid geometric grid phantom with 840 fiducial markers for distortion quantification on a 3T MRI scanner. To choose the optimal filling solution, an anthropomorphic RANDO phantom was employed, and 1 mmol/L gadolinium was chosen due to clinical relevance. An automated Python-based software (version 3.7.1) was developed for efficient detection and matching of phantom inserts between MRI and CT scans. A series of MRI acquisition parameter optimizations were systematically evaluated. The standard SRS protocol exhibited the highest average distortion of 1.301 mm. Notably, reversing the phase-encoding direction to anterior–posterior (AP) reduced the mean distortion to 0.725 mm, a 44.27% decrease, while the maximum distortion was reduced by 15.65%. The AP phase sequence maintained acquisition time, SAR, SNR, and CNR within acceptable limits. Additional distortion reduction was achieved by increasing the flip angle from 12° to 18°. In this work, we succeeded in significantly reducing the mean distortion observed in phantom images. As the gadolinium concentration used in the phantom is clinically similar to the gadolinium concentration observed in patients undergoing MRI scans with contrast agents, the achieved distortion reduction is prospectively reproducible in patients.