Grønningsæter Simen Rykkje, Blakkisrud Johan, Selboe Silje, Revheim Mona-Elisabeth, Bruland Øyvind Sverre, Bønsdorff Tina Bjørnlund, Larsen Stein Gunnar, Stokke Caroline
Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
Faculty of Medicine, University of Oslo, Oslo, Norway.
Front Med (Lausanne). 2023 Feb 8;10:1058914. doi: 10.3389/fmed.2023.1058914. eCollection 2023.
Two ongoing phase I studies are investigating the use of radium-224 adsorbed to calcium carbonate micro particles (Ra-CaCO-MP) to treat peritoneal metastasis originating from colorectal or ovarian cancer. The aim of this work was to study the level of radiation exposure from the patients to workers at the hospital, carers and members of the public.
Six patients from the phase 1 trial in patients with colorectal cancer were included in this study. Two days after cytoreductive surgery, they were injected with 7 MBq of Ra-CaCO-MP. At approximately 3, 24 and 120 h after injection, the patients underwent measurements with an ionization chamber and a scintillator-based iodide detector, and whole body gamma camera imaging. The patient was modelled as a planar source to calculate dose rate as a function of distance. Scenarios varying in duration and distance from the patient were created to estimate the potential effective doses from external exposure. Urine and blood samples were collected at approximately 3, 6, 24, 48 and 120 h after injection of Ra-CaCO-MP, to estimate the activity concentration of Ra and Pb.
The patients' median effective whole-body half-life of Ra-CaCO-MP ranged from 2.6 to 3.5 days, with a mean value of 3.0 days. In the scenarios with exposure at the hospital (first 8 days), sporadic patient contact resulted in a range of 3.9-6.8 μSv per patient, and daily contact resulted in 4.3-31.3 μSv depending on the scenario. After discharge from the hospital, at day 8, the highest effective dose was received by those with close daily contact; 18.7-83.0 μSv. The highest activity concentrations of Ra and Pb in urine and blood were found within 6 h, with maximum values of 70 Bq/g for Ra and 628 Bq/g for Pb.
The number of patients treated with Ra-CaCO-MP that a single hospital worker - involved in extensive care - can receive per year, before effective doses of 6 mSv from external exposure is exceeded, is in the order of 200-400. Members of the public and family members are expected to receive well below 0.25 mSv, and therefore, no restrictions to reduce external exposure should be required.
两项正在进行的I期研究正在调查吸附于碳酸钙微粒（镭 - 碳酸钙微粒，Ra - CaCO - MP）上的镭 - 224用于治疗源自结直肠癌或卵巢癌的腹膜转移的情况。这项工作的目的是研究患者对医院工作人员、护理人员和公众造成的辐射暴露水平。
本研究纳入了6例来自结直肠癌患者I期试验的患者。在肿瘤细胞减灭术后两天，他们被注射了7 MBq的Ra - CaCO - MP。在注射后约3、24和120 小时，患者接受电离室和基于闪烁体的碘探测器测量以及全身γ相机成像。将患者建模为平面源以计算作为距离函数的剂量率。创建了不同持续时间和与患者距离的场景，以估计外部暴露的潜在有效剂量。在注射Ra - CaCO - MP后约3、6、24、48和120 小时采集尿液和血液样本，以估计镭和铅的活度浓度。
患者体内Ra - CaCO - MP的有效全身中位半衰期为2.6至3.5天，平均值为3.0天。在医院暴露的场景（前8天）中，偶尔与患者接触导致每位患者的剂量范围为3.9 - 6.8 μSv，每日接触导致的剂量为4.3 - 31.3 μSv，具体取决于场景。出院后，在第8天，日常密切接触者接受的有效剂量最高；为18.7 - 83.0 μSv。尿液和血液中镭和铅的最高活度浓度在6小时内出现，镭的最大值为70 Bq/g，铅的最大值为628 Bq/g。
在超过来自外部暴露的6 mSv有效剂量之前，一名参与广泛护理的医院工作人员每年能够接触的接受Ra - CaCO - MP治疗的患者数量约为200 - 400例。公众和家庭成员预计接受的剂量远低于0.25 mSv，因此，无需采取减少外部暴露的限制措施。
