Comparing Two Methods to Measure Nasogastric Tube Length

The goal of this clinical trial is to learn if using a novel nasogastric tube assisted placement system (NCKU-NG system) can more accurately place the nasogastric tube at the optimal position in the stomach compared to conventional blind insertion techniques in adult inpatients requiring nasogastric tube placement. The main questions it aims to answer are: * Does the NCKU-NG system improve the accuracy of nasogastric tube placement at the optimal gastric position compared to standard blind insertion? * Does the NCKU-NG system reduce the rate of misplacement (such as entry into the airway or inadequate gastric depth), number of repeated attempts, and complication rate compared to the conventional method? * Can estimation of nasogastric tube length using the NCKU-NG system provide a more reliable reference than external measurement or X-ray? Researchers will compare patients randomized to nasogastric tube insertion with the NCKU-NG system (intervention arm) versus conventional blind insertion following standard external measurement methods (control arm) to see if the NCKU-NG system improves placement accuracy and reduces adverse events. Participants will: * Be randomized to one of two groups: * Intervention group: Receive nasogastric tube insertion using the NCKU-NG system (video-assisted real-time visualization, with active confirmation of passage through the esophagogastric junction and final position in the stomach based on sidehole location). * Control group: Receive traditional nasogastric tube blind bedside insertion based on standard measurement (eg. Nose-Earlobe-Xiphoid + 10 cm). * All procedures will use the same material nasogastric tube (16 French polyurethane radiopaque tube). * Undergo confirmation of tube position by X-ray within 8 hours post-insertion for both groups. * Have the following outcomes assessed: * Placement accuracy (percentage of tubes placed at optimal predefined gastric position) * Number of placement attempts and failures