Objective To evaluate the application of the placement of titanium clips in the upper and lower tumor margins in precision radiotherapy for early esophageal cancer. Methods:Seventeen patients with early esophageal cancer underwent endoscopy-guided implantation of titanium clips to mark the upper and lower tumor margins. CT-based simulation was performed to delineate the gross tumor volume ( GTV) . The application value of this technology in precision radiotherapy was evaluated. Results:For all patients (including 13 cases with initial treatment and 4 patients requiring radiotherapy after endoscopic resection), the esophageal tumors were not explicitly displayed on CT and barium meal images and the GTV range could not be accurately determined. The esophageal tumors were marked by successful placement of at least one titanium clip in the upper and lower tumor margins. Subsequently, the esophageal tumors were successfully displayed on CT simulation and the target area was accurately delineated. No grade 3-4 adverse events, such as bleeding and perforation occurred. Conclusion Endoscopy-guided titanium clip placement is convenient and feasible for early esophageal cancer, which is of clinical significance for determining the target area of radiotherapy.

Objective:The respiratory waveform of lung cancer patients based on 4D-CT respiratory gating was analyzed to evaluate the accuracy of gating during radiotherapy, and to explore the off-target in the 4D-CT respiratory gating radiotherapy.Methods:Clinical data of 18 patients with lung cancer admitted to Radiotherapy Department of Jiangsu Cancer Hospital were collected to obtain the respiratory waveform data during 4D-CT respiratory gating radiotherapy. The waveform in each treatment working cycle was compared with the waveform in 4D-CT scan to study whether there was a possibility of the off-target in the treatment of lung cancer patients.Results:There were 154 treatment sessions and 20,790 treatment breathing cycles in 18 patients, among which the threshold of gated opening beam miss amplitude (Δm-en) was greater than 0 in 95 treatment breathing cycles in 7 patients, accounting for 0.46% of all breathing cycles, and the threshold of gated closing beam miss amplitude (Δm-dis) was greater than 0 in 1419 treatment breathing cycles in 13 patients, accounting for 6.83% of all cycles. Among the 13 patients withΔm-dis greater than 0, actual tumor range of motion (R G) was greater than the sum of the value of target margin (M) and the value of plan tumor range of motion (R T) in 7 patients, R G was more than 1.5 times of M+R T in 7 patients, and there were also 7 patients in the phase of rapid rise and fall of respiratory curve. The correlation efficients between R G-M-R T and the percentage of beam on miss phase (T en%) and the percentage of beam closing off phase (T dis%) were 0.41 and 0.57, respectively. Conclusion:When R G is more than 1.5 times of M+R T value and the gating beam on phase contains the phases in the rapid rise and fall of the respiratory curve, the possibility of the off-target during radiotherapy is significantly increased.

Objective To construct a Type 1 diabetes model in miniature pigs and explore postoperative care strategies for effectively prolonging the survival time of the model pigs. Methods Seven Banna miniature pigs were selected for pancreatectomy. Glucose, vitamins, and antibiotics were administered for 3-5 days after surgery to aid recovery. Blood glucose and urine glucose levels were measured twice a day in the morning and evening to adjust insulin supplementation accordingly. The model pigs were observed daily and records were kept, including orexis, psychosis, weakness, skin ulcer, and feces and urine. Body weight was measured weekly until the death of the model animals. Based on the model pigs' condition, glucose injection and Ringer's lactate solution were administered to supplement nutrition and correct electrolyte imbalances. Results All seven Banna miniature pigs showed typical symptoms of diabetes: random blood glucose levels higher than 11.1 mmol/L after pancreatectomy, far exceeding the average blood glucose level of 6.0 mmol/L in normal pigs; positive urine glucose; and progressive weight loss. These features indicated the successful construction of Type 1 diabetes model. Additionally, Type 1 diabetic pigs that survived more than 8 weeks showed progressive hair loss and skin ulceration. Euthanasia was performed on model pigs when they were unable to stand or even eat independently, and pathological examination and HE staining were conducted on tissues collected from affected organs such as the liver, kidneys, and skin. Pathological sections revealed liver congestion, massive glycogen accumulation, ballooning degeneration of hepatocytes, and progressive liver fibrosis, along with glomerular congestion, vacuolar degeneration in renal tubular epithelial cells, proteinuria, dermal congestion, thinning of vascular walls, and varying degrees of parakeratosis and dyskeratosis in the liver, kidneys, and skin tissues due to prolonged hyperglycemia. The average survival time of the constructed Banna miniature pig diabetes model was 44 d, with a maximum survival time of 121 d. Conclusion Type 1 diabetes model can be constructed successfully in Banna miniature pigs through pancreatectomy. With meticulous postoperative care, a long-term Type 1 diabetes model with significant complications can be achieved, providing a stable large-animal model for Type 1 diabetes treatment strategies.