Deep Vision Servo Hand-Eye Coordination Planning Study for Sorting Robots

Within the context of large-scale symmetry, a study on deep vision servo hand-eye coordination planning for sorting robots was conducted according to the problems of low recognition-sorting accuracy and efficiency in existing sorting robots. In order to maintain the symmetry of the picking robot, a small telescopic sorting robot with RealSense depth vision servo embedded in the manipulator was developed. The workspace and posture of picking parcels were analyzed, and the coordinate transformation model of hand-eye coordination was established for the “Eye-in-hand” mode. The hand-eye coordinated sorting test shows that the average positioning accuracy of the end in the X, Y and Z directions is 3.49 mm, 2.76 mm and 3.32 mm respectively, and the average time is 19.19 s. Among them, the average time for the mechanical arm to pick up the package from the initial position is 12.02 s, the average time for intermediate identification and calculation is 3.79 s, and the average time for placing the package is 6.9 s. The time consumed by robot arm’s action accounts for 79.8% of the whole cycle. The robot structure and the hand-eye coordination strategy with RealSense depth vision servo embedded in the robot can meet picking operation requirements, and the design of a picking robot proposed in this paper can greatly improve the coordination symmetry of fruit target recognition, detection, and picking.

Comparison of Absolute Dose Achievable Between Helical Tomotherapy and RapidArc in Total Dura Mater Irradiation for Child Cancer

Background and Purpose: In this study, the absolute dose achievable between helical tomotherapy (HT) plans and RapidArc (RA) plans for total dura mater irradiation (TDMI) was compared. Materials and methods: A planning study was conducted on nine children's case datasets with dura mater metastasis of neuroblastoma. The target included the entire calvarium and skull base and formed a closed volume with a certain thickness around the brain. HT and RA plans with four coplanar full arcs (RA4) with half-field technique were generated for the comparison of absolute dose achievable. In total, 30.6 Gy was prescribed as D95% (ie, dose to 95% of PTV volume). Results: In the dosimetric comparison between the two modalities, HT provided more homogenous dose distribution than RA4 (mean HI5−95%: 1.046 vs 1.088, P < .001). The V107% and D2Gy of PTV in HT versus RA4 were 3.06% versus 30.47% and 32.59 Gy versus 33.45 Gy, respectively. HT reduced the Dmean and V5Gy of the brain, brainstem, and hippocampus by 25%–48% and 27%–56% compared with RA4, respectively. Conclusion: Both techniques could provide sufficient coverage for targets, but HT offered more homogenous dose to PTV and lower dose to the central region of the brain involving the brainstem and hippocampus. RA4 could be completed in a shorter time with lower MUs, but with relatively higher dose to the brain or hippocampus. In terms of dosimetry, HT may improve long-term cognitive decline in these young pediatric patients with TDMI.

Preoperative Chemoradiotherapy for Gastroesophageal Junction Adenocarcinoma Modified by PET/CT: Results of Virtual Planning Study

Background and Objectives: The treatment of gastroesophageal junction (GEJ) adenocarcinoma consists of either perioperative chemotherapy or preoperative chemoradiotherapy. Radiotherapy (RT) in the neoadjuvant setting is associated with a higher probability of resections with negative margins (R0) and better tumor regression rate, which might be enhanced by incrementing RT dose with potential impact on treatment results. This virtual planning study demonstrates the feasibility of increasing the dose to GEJ tumor and involved nodes using PET/CT imaging. Materials and Methods: 16 patients from the chemoradiotherapy arm of the phase II GastroPET study were treated by a prescribed dose of 45.0 Gray (Gy) in 25 fractions. PET/CT was performed before treatment. The prescribed dose was virtually boosted on PET/CT-positive areas to 54.0 Gy by 9 Gy in 5 fractions. Dose-volume histograms (DVH) were compared, and normal tissue complication (NTCP) modeling was performed for both dose schedules. Results: DVHs were exceeded in mean heart dose in one case for 45.0 Gy and two cases for 54.0 Gy, peritoneal space volume criterion V45Gy < 195 ccm in three cases for 54.0 Gy and V15Gy < 825 ccm in one case for both dose schedules. The left lung volume of 25 Gy isodose exceeded 10% in most cases for both schedules. The NTCP values for the heart, spine, liver, kidneys and intestines were zero for both schemes. An increase in NTCP value was for lungs (median 3.15% vs. 4.05% for 25 × 1.8 Gy and 25 + 5 × 1.8 Gy, respectively, p = 0.013) and peritoneal space (median values for 25 × 1.8 Gy and 25 + 5 × 1.8 Gy were 3.3% and 14.25%, respectively, p < 0.001). Conclusion: Boosting PET/CT-positive areas in RT of GEJ tumors is feasible, but prospective trials are needed.

Feasibility and safety of shortened hypofractionated high dose palliative lung radiotherapy – A retrospective planning study

Objective: Assess the safety and feasibility of shortened hypo-fractionated high dose palliative lung radiotherapy. Methods: Fifteen palliative lung radiotherapy patients previously treated with the standard 36 Gy in 12 fractions (12F) schedule were non-randomly selected to achieve a representative distribution of tumour sizes, volumes, locations and staging. Plans were produced using 30 Gy in 5 fractions (5F) and 30 Gy in 6 fractions (6F) using a 6MV FFF co-planar VMAT technique. These plans were optimised to meet dose constraints for both PTVs and OARs where established OAR constraints were expressed as BED. The potential safety of the delivery of these plans was assessed using these BEDs and also with reductions of 10% and 20% to account for effects of chemotherapy or surgery. Results: For all 5F and 6F plans the mandatory constraints using the full BED were met, as with all 6F plans with 10% BED reductions, but reduced to 6 patients using 5F. Three of 15 5F and 6 of 15 6F plans met the 20% BED reductions. Conclusion: It is potentially safe and feasible to deliver high dose palliative radiotherapy using the 5F or 6F regimes described, when carefully planned to comparable OAR BEDs as for 12F standard. It appears that the toxicity from either of these regimes should be within acceptable limits provided that the dose constraints described can be adhered to. A Phase II study would be required to fully assess the safety and feasibility. The outcomes from such a study could potentially reduce the number of patient hospital visits for radiotherapy, thus benefiting the patient and the clinical service by optimising resource utilisation. Advances in Knowledge: Shortened hypo-fractionated high dose palliative lung radiotherapy is technically feasible provided OAR constraints are respected.

A Trade-Off Model of Intentional Thinking for Pleasure

We investigated intentional thinking for pleasure, defined as the deliberate attempt to have pleasant thoughts while disengaged from the external world. We propose a Trade-Off Model that explains when and why thinking for pleasure is enjoyable: people focus on personally meaningful thoughts when thinking for pleasure (especially when prompted to do so), which increases their enjoyment, but they find it difficult to concentrate on their thoughts, which decreases their enjoyment. Thus, the net enjoyment of thinking for pleasure is a trade-off between its benefits (personal meaningfulness) and costs (difficulty concentrating). To test the model, we compared intentional thinking for pleasure to four alternate activities in three studies. Thinking for pleasure was more enjoyable than undirected thinking (Study 1) and planning (Study 3), because it was more meaningful than these activities while requiring a similar level of concentration. Thinking for pleasure was just as enjoyable as playing a video game (Study 2) or unprompted idle time activities (Study 3), but for different reasons: It was more meaningful than these activities, but required more concentration. We discuss the implications of these findings for what people might choose to do during idle times.