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临床检查能确诊大多数有症状的头颈部肿瘤.但很难确定肿瘤在粘膜下扩散及肿瘤向深剖组织浸涧的情况,用触诊法也很难确诊有无淋巴结转移。常规影像学检查。如CT、MR、X线对肿瘤的早期破坏以及淋巴结转移的诊断可靠性差。临床和影像学的另一难题是对肿瘤复发的诊断,由于术后瘢痕形成给肿瘤复发的诊断造成困难.这就需要有一种影像技术,既能准确定位原发肿瘤部位,又能早期确定有无淋巴结转移以及肿瘤复发。 正电子扫描(PET)是一种运用放射性同位素衰变发射正电子而成像的影像技术。这些正电子在组织中穿过很短的距离,然后与阴极发射的电子结合,释放出两条几乎呈180°角的高能光子束(γ射线)。这两条γ射线同时被相反的探测器接受并形成三维立体图像(PET
Clinical examination can confirm the diagnosis of most symptomatic head and neck cancers. However, it is difficult to determine whether the tumor spreads in the submucosal area and the tumor is deeply immersed in deep-seated tissue. Palpation is also difficult to diagnose with or without lymph node metastasis. General imaging examination. For example, CT, MR, and X-ray have poor reliability in the diagnosis of early tumor destruction and lymph node metastasis. Another difficulty in clinical and imaging studies is the diagnosis of recurrence of the tumor. Because postoperative scar formation can cause difficulty in diagnosing tumor recurrence, there is a need for an imaging technique that can both accurately locate the primary tumor site and determine early on. No lymph node metastasis and tumor recurrence. Positron scanning (PET) is an imaging technique that uses radioactive isotopes to decay and emit positrons. These positrons travel a very short distance in the tissue and then combine with the electrons emitted from the cathode, releasing two high-energy photon beams (γ-rays) with an angle of almost 180°. The two gamma rays are simultaneously received by the opposite detector and form a three-dimensional image (PET