Hansson Marie, Isaksson Mats, Berg Gertrud
Department of Radiation Physics, Göteborg University, Göteborg, Sweden.
Cancer Inform. 2008;6:51-7. Epub 2008 Apr 10.
Iodine is enriched and stored in the thyroid gland. Due to several factors, the size of the thyroid iodine pool varies both between individuals and within individuals over time. Excess iodine as well as iodine deficiency may promote thyroid cancer. Therefore, knowledge of iodine content and distribution within thyroid cancer tissue is of interest. X-ray fluorescence analysis (XRF) and secondary ion mass spectrometry (SIMS) are two methods that can be used to assess iodine content in thyroid tissue. With both techniques, choice of sample preparation affects the results. Aldehyde fixatives are required for SIMS analysis while a freezing method might be satisfactory for XRF analysis. The aims of the present study were primarily to evaluate a simple freezing technique for preserving samples for XRF analysis and also to use XRF to evaluate the efficacy of using aldehyde fixatives to prepare samples for SIMS analysis. Ten porcine thyroids were sectioned into four pieces that were either frozen or fixed in formaldehyde, glutaraldehyde, or a modified Karnovsky fixative. The frozen samples were assessed for iodine content with XRF after 1 and 2 months, and the fixed samples were analyzed for iodine content after 1 week. Freezing of untreated tissue yielded no significant iodine loss, whereas fixation with aldehydes yielded an iodine loss of 14-30%, with Karnovsky producing the least loss.
碘在甲状腺中富集并储存。由于多种因素，甲状腺碘池的大小在个体之间以及个体内部随时间而变化。碘过量以及碘缺乏都可能促进甲状腺癌。因此，了解甲状腺癌组织中碘的含量和分布情况备受关注。X射线荧光分析（XRF）和二次离子质谱分析（SIMS）是两种可用于评估甲状腺组织中碘含量的方法。对于这两种技术，样品制备方法的选择都会影响结果。SIMS分析需要使用醛类固定剂，而冷冻方法可能适用于XRF分析。本研究的目的主要是评估一种用于保存样品以进行XRF分析的简单冷冻技术，同时使用XRF评估使用醛类固定剂制备用于SIMS分析的样品的效果。将10个猪甲状腺切成4块，分别进行冷冻或用甲醛、戊二醛或改良的 Karnovsky固定剂固定。冷冻样品在1个月和2个月后用XRF评估碘含量，固定样品在1周后分析碘含量。未经处理的组织冷冻后碘没有明显损失，而用醛类固定则导致碘损失14% - 30%，其中Karnovsky固定剂造成的损失最小。
