Malmud L S, Charkes N D
Clin Orthop Relat Res. 1975(107):112-22. doi: 10.1097/00003086-197503000-00013.
Bone scanning is most useful in the detection of bone metastases. The recent introduction of new radiopharmaceuticals and instrumentation has reduced the time needed to perform the study and its relative cost, while increasing the usefulness of the study in detecting roentgenographically occult diseases. Metastatic disease is used as the pathophysiologic model for understanding the principles of bone scanning. When a tumor invades bone, in addition to causing bone destruction, it also causes reactive bone formation or repair. It is here that radioisotopes are of considerable value, since some radionuclides are incorporated into the hydroxyapatite crystals of reactive bone. Bone repair is described as occurring in three phases. In Phase I, the roentgenogram shows no change in bone density, but the scan is abnormal. In Phase II, both scintigraphic and roentgenographic abnormalities increase, and in Phase III, when the osteoid has calcified completely, the roentgenogram shows radiodensities and the scan appears almost normal. Fewer than 5 per cent of patients have a normal scan in the presence of an abnormal roentgenogram. Presently, most bone scans are performed with phosphate compounds labeled with -99m-Tc. In the past, 85-Sr, 87M-Sr, and 18-F were more broadly used. Scanning may be performed on either a rectilinear scanner or a scintophoto (gamma) camera. Areas which are abnormal on bone scan should be interpreted with current roentgenograms in the light of clinical findings.
骨扫描在检测骨转移瘤方面最为有用。最近新型放射性药物和仪器的引入，减少了进行该项检查所需的时间及其相对成本，同时提高了在检测X线隐匿性疾病方面的实用性。转移性疾病被用作理解骨扫描原理的病理生理模型。当肿瘤侵犯骨骼时，除了导致骨质破坏外，还会引起反应性骨形成或修复。正是在这一点上，放射性同位素具有重要价值，因为一些放射性核素会掺入反应性骨的羟基磷灰石晶体中。骨修复过程分为三个阶段。在第一阶段，X线片显示骨密度无变化，但扫描结果异常。在第二阶段，闪烁扫描和X线片异常均加重，而在第三阶段，当类骨质完全钙化时，X线片显示出放射密度，扫描结果几乎正常。在X线片异常的情况下，扫描结果正常的患者不到5%。目前，大多数骨扫描使用用-99m-Tc标记的磷酸盐化合物进行。过去，85-Sr、87M-Sr和18-F的应用更为广泛。扫描可使用直线扫描仪或闪烁照相（γ）相机进行。骨扫描异常的部位应结合当前的X线片并根据临床发现进行解读。
