Hospital Clínico Universitario de Valladolid, Unidad de Radiofísica, Valladolid, Spain.
Health Phys. 2011 Aug;101 Suppl 2:S110-5. doi: 10.1097/HP.0b013e318209459c.
In nuclear medicine, estimating the radioactivity contained in the urine of patients treated with I and discharged to the environment could prevent the exposure of a population to radioactive effluents and the pollution of the aquatic environment with ionizing radiation. This can be a regulatory requirement (as in Spain) or requested by the sewer authority. Seventy-nine differentiated thyroid cancer cases (undergone as inpatients) and 187 hyperthyroidism cases (undergone as outpatients) were treated in our hospital with I throughout the year 2009. In hyperthyroidism treatments, the effective elimination constant was used to calculate the corresponding discharged activity in the urine, giving an activity level always below 0.7 GBq. In differentiated thyroid cancer treatments, patient's urine was collected in storage tanks during the hospitalization. Measurements of external exposure at 1 m made every day were used to calculate the activity contained in the urine. The tank activity was always below 15 GBq, but always higher than 2 GBq. Obtained results show that effective doses to sewage workers, received from liquid discharges, can only be reduced to less than 10 μSv if storage tanks are installed. Without tanks, 157 μSv can be reached, above the constrain dose used in nuclear installations (100 μSv). Our calculations may be helpful to the regulatory authority to review the clinical radiation waste normative, especially in countries where the discharges are released directly into public sewage plants.
在核医学中，估算接受 I 治疗并排放到环境中的患者尿液中的放射性活度，可以防止放射性流出物使人群暴露于辐射下，并防止放射性污染水环境污染。这可能是法规要求（如在西班牙），也可能是污水管理部门的要求。在 2009 年全年，我院对 79 例分化型甲状腺癌病例（住院治疗）和 187 例甲状腺功能亢进症病例（门诊治疗）进行了 I 治疗。在甲状腺功能亢进症的治疗中，使用有效消除常数来计算尿液中的相应排出活性，得到的活性水平始终低于 0.7GBq。在分化型甲状腺癌的治疗中，患者的尿液在住院期间储存在储存罐中。每天进行的 1 米处的外照射测量用于计算尿液中的放射性活度。罐中的放射性活度始终低于 15GBq，但始终高于 2GBq。获得的结果表明，如果安装了储存罐，从液体排放中接受的污水工人的有效剂量可减少到低于 10μSv。如果没有储罐，则可达到 157μSv，超过核设施中使用的约束剂量（100μSv）。我们的计算结果可能有助于监管机构审查临床放射性废物规范，特别是在那些将排放物直接排放到公共污水处理厂的国家。
