Radiation dose and factors related to exceeding the diagnostic reference level in 496 transnasal ileus tube placement procedures from the REX-GI study

Abstract

Objective: We aimed to examine the factors contributing to radiation exposure exceeding the DRL of the transnasal ileus tube placement in this post hoc analysis from the cohort of the REX-GI study. Methods: Patients with transnasal ileus tubes were enrolled in the rex-gi study from may 2019 to december 2020. We investigated the endoscope insertion time (min), procedure time (min), tube insertion length (cm), fluoroscopy time (FT: min), air kerma at the patient entrance reference point (Ka.r: mGy), and air kerma–area product (PKA: Gycm2). The third quartile value of the PKA value was calculated as the diagnostic reference level (DRL) value. We explored the factors associated with radiation exposure exceeding the DRL. Results: In the REX-GI study, 496 patients who underwent transnasal ileus tube placement were enrolled. The median age of the patients was 71 years. The median endoscopy insertion time, procedure time, and tube insertion length were 6 min, 20 min, and 170 cm, respectively. The third quartile/median FT, Ka.r, and PKA were 18/11.9 min, 99.2/54.4 mGy, and 46.9/28 Gycm2, respectively. The third quartile value of PKA (47 Gycm2) was set as the DRL value. There were differences in distribution by the hospital. Compared with procedures under the DRL, the FT (19 vs 10 min), procedure time (25 vs 18 min), and tube insertion length (185 vs 165 cm) were significantly longer for procedures above the DRL. Conclusion: We report the DRL for transnasal ileus tube placement in Japan. A longer procedure time and tube insertion length may be associated with DRL exceedance. Advances in knowledge: Transnasal ileus tube placement under fluoroscopy guidance is a standard clinical procedure for bowel obstruction. However, the appropriate radiation dose level has not yet been established. We report the (DRL) for transnasal ileus tube placement in Japan. A longer procedure time and tube insertion length may be associated with DRL exceedance.