Levine Children's Hospital, Charlotte, NC, USA,
Adv Exp Med Biol. 2014;804:291-304. doi: 10.1007/978-3-319-04843-7_16.
Osteosarcoma is a cancer characterized by formation of bone by malignant cells. Routine bone scan imaging with Tc-99m-MDP is done at diagnosis to evaluate primary tumor uptake and check for bone metastases. At time of relapse the Tc-99m-MDP bone scan also provides a specific means to assess formation of bone by malignant osteosarcoma cells and the potential for bone-seeking radiopharmaceuticals to deliver radioactivity directly into osteoblastic osteosarcoma lesions. This chapter will review and compare a bone-seeking radiopharmaceutical that emits beta-particles, samarium-153-EDTMP, with an alpha-particle emitter, radium-223. The charged alpha particles from radium-223 have far more mass and energy than beta particles (electrons) from Sm-153-EDTMP. Because radium-223 has less marrow toxicity and more radiobiological effectiveness, especially if inside the bone forming cancer cell than samarium-153-EDTMP, radium-223 may have greater potential to become widely used against osteosarcoma as a targeted therapy. Radium-223 also has more potential to be used with chemotherapy against osteosarcoma and bone metastases. Because osteosarcoma makes bone and radium-223 acts like calcium, this radiopharmaceutical could possibly become a new targeted means to achieve safe and effective reduction of tumor burden as well as facilitate better surgery and/or radiotherapy for difficult to resect large, or metastatic tumors.
骨肉瘤是一种由恶性细胞形成骨的癌症。在诊断时，通常使用 Tc-99m-MDP 进行常规骨扫描成像，以评估原发性肿瘤摄取情况并检查是否有骨转移。在复发时，Tc-99m-MDP 骨扫描还提供了一种特定的方法来评估恶性骨肉瘤细胞形成的骨骼，以及放射性药物是否有潜力将放射性直接输送到成骨性骨肉瘤病变中。本章将回顾和比较一种发射β粒子的骨靶向放射性药物，即钐-153-EDTMP，与一种发射α粒子的放射性药物，镭-223。镭-223 的带电荷的α粒子比钐-153-EDTMP 的β粒子（电子）具有更大的质量和能量。由于镭-223 的骨髓毒性较小，放射生物学效应更强，特别是在形成骨的癌细胞内，因此比钐-153-EDTMP 更有可能成为针对骨肉瘤的靶向治疗方法。镭-223 也更有可能与化疗联合用于治疗骨肉瘤和骨转移。由于骨肉瘤会形成骨骼，而镭-223 的作用类似于钙，因此这种放射性药物有可能成为一种新的靶向手段，安全有效地减轻肿瘤负担，并促进更难切除的大型或转移性肿瘤的更好手术和/或放疗。
