Objective:To investigate whether adjuvant skin-marker positioning can decrease the set-up errors in overweight patients with thoracic and abdominal tumors.Methods:A total of 60 overweight patients with thoracic and abdominal tumors treated with radiotherapy in the First Affiliated of Fujian Medical University between January 2018 and December 2018 were randomly divided into two groups. In group A, conventional skin-marker positioning was adopted. In group B, conventional skin-marker positioning combined with adjuvant skin-marker position was employed. All patients were immobilized with thermoplastic positioning body membrane with head-body plate fixation. The set-up errors in the right-left, head-foot and dorsoventral directions were obtained from cone-beam CT (CBCT) scan system before radiation delivery. The set-up errors were statistically compared between two groups by using t-test. Results:In group A, the set-up errors in the right-left, head-foot and dorsoventral directions were (4.47±2.91) mm, (5.43±2.61) mm and (3.87±2.40) mm, significantly higher compared with (2.97±1.68) mm, (3.21±1.62) mm and (2.59±1.57) mm, respectively (all P<0.001). Conclusion:Adjuvant skin-marker positioning method can reduce the set-up errors and enhance the positioning repeatability in overweight patients with thoracic and abdominal tumors receiving radiotherapy.

Drug delivery with customized combinations of drugs, controllable drug dosage, and on-demand release kinetics is critical for personalized medicine. In this study, inspired by successive opening of layered structures and compartmentalized structures in plants, we designed a multiple compartmentalized capsular structure for controlled drug delivery. The structure was designed as a series of compartments, defined by the gradient thickness of their external walls and internal divisions. Based on the careful choice and optimization of bioinks composed of gelatin, starch, and alginate, the capsular structures were successfully manufactured by fused deposition modeling three-dimensional (3D) printing. The capsules showed fusion and firm contact between printed layers, forming complete structures without significant defects on the external walls and internal joints. Internal cavities with different volumes were achieved for different drug loading as designed. In vitro swelling demonstrated a successive dissolving and opening of external walls of different capsule compartments, allowing successive drug pulses from the capsules, resulting in the sustained release for about 410 min. The drug release was significantly prolonged compared to a single burst release from a traditional capsular design. The bioinspired design and manufacture of multiple compartmentalized capsules enable customized drug release in a controllable fashion with combinations of different drugs, drug doses, and release kinetics, and have potential for use in personalized medicine.