#5819 HAEMODIALYSIS EFFECT ON METABOLIC THERAPY WITH [131INA]: A COMPARATIVE STUDY

Abstract

Abstract Background and Aims The use of [131INa] therapy in patients undergoing haemodialysis (HD) is still controversial. Considering that the main elimination of 131I is urinary and the sessions of HD take place in wards full of other patients, various modifications should be made in the therapy. Due to the limited bibliography and the lack of consensus in clinical guidelines we developed this comparative study between two patients on HD treated with [131INa]. External dose rate measurement (EDRM), time of hospitalization, timing of dialysis after the administration of [131INa] and the status of contamination of dialysis machine were considered. Method Two patients on HD were treated with [131INa] in June 2021. A 74years old women with hyperthyroidism due to a multinodular goitre, resistant to antithyroid drugs (PT1). A 49years old man candidate to ablation treatment with low activity of [131INa] after a total thyroidectomy due to differentiated thyroid cancer (pT2N0) (PT2). The recommended activity was administered according to clinical indication. PT1 received 555MBq and PT2 received 1110 MBq of [131INa] in Metabolic Therapy Unit (MTU) after the first HD session in the nephrology ward. The following HD sessions were in MTU (Wed.-Fri.). High-flux dialysis was performed using a Reverse Osmosis portable system. The hospital stay was 5 days (Mo at Fri) for each patient. EDRM at 1 meter was measured three times a day. Liquid samples from HD machine (dialysis fluid, water wash) were obtained every day at the same time before and after each session and radioactivity was analysed. Results EDRM after second HD at discharge was 12 and 7,4mcSv/h in PT1 and PT2 respectively. After first HD both patients reached EDR <40mcSv/h (22 and18 mcSv/h). Red bone marrow dose was 130,76mGy and 110,42mGy respectively. Radioactivity in dialysis fluid was: 0,00999MBq PT1- 0,00259MBq PT2 after first HD; 0,0022MBq PT1- 0,00074MBq PT2 after second HD. No radioactivity was detected in wash water of dialysis equipment in both patients during each HD session. There was no secondary complications due to overhydration or dyslectrolythemias. Conclusion External dose rate measurement is key to decide if patients undergoing HD are ready to be discharge. Once EDRM <40mcSv/h at 1 meter has been reached, patients could immediately return to their dialysis centre following the protection radiology rules and so we must always respect the distance between the patients, if that cannot be performed the session will be in the hospital. There is no need to modify radioiodine activities neither timing of HD sessions as red bone marrow dose do not exceed recommended value (2Gy). There is no contamination of HD machine, it could be used after usual decontamination for other patients.