Yttrium-90-labeled microsphere tracking during liver selective internal radiotherapy by bremsstrahlung pinhole SPECT: feasibility study and evaluation in an abdominal phantom.
Yttrium-90-labeled microsphere tracking during liver selective internal radiotherapy by bremsstrahlung pinhole SPECT: feasibility study and evaluation in an abdominal phantom.
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DOI：
10.1186/2191-219x-1-32
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发表时间：
2011-12-02
期刊：
影响因子：
3.2
通讯作者：
Jamar F
中科院分区：
文献类型：
--
作者：
Walrand S;Hesse M;Demonceau G;Pauwels S;Jamar F
本研究的目的是评估针孔准直器是否比平行孔准直器更适合轫致辐射单光子发射计算机断层扫描（SPECT），如果是肯定的，则评估针孔轫致辐射SPECT，包括患者体内散射的简单模型，是否可以在肝脏选择性内放疗（SIRT）中提供快速剂量学评估。使用两个长口径平行孔准直器：一个中能量通用[MEGP]和一个高能通用[HEGP]，以及一个中能量针孔准直器[MEPH]，对一个包括1个冷球和5个热球的腹部型幻影进行了轫致辐射SPECT。此外，还获得了真实肝脏- sirt幻影的10个螺旋MEPH spect（获取时间3.6 min）。在对SPECT进行散点校正后，MEPH SPECT的对比恢复系数（CRC）明显优于MEGP和HEGP SPECT。通过散射校正，MEPH SPECT获得的CRC仍然得到改善，并且与正电子发射断层扫描[PET]获得的36、30（冷）、28和24 mm直径球体的CRC相当：SPECT的CRC分别为1.09、0.59、0.91和0.69，PET的CRC分别为1.07、0.56、0.84和0.63。然而，对于直径为19mm的球体，MEPH SPECT给出了最好的CRC: SPECT CRC = 0.56, PET CRC = 0.01。3.6分钟螺旋MEPH SPECT为肝脏- sirt幻影提供了准确且可重复的活性估计：相对偏差= 10±1%。使用针孔准直器的轫致SPECT比使用平行孔准直器获得更好的CRC。不同的设计和更好的衰减材料用于准直（钨代替铅）解释了这一结果。此外，增加了对幻影内部散射的分析建模，结果几乎完全恢复了对比度。这填补了90y - pet和微应力针孔SPECT之间的性能差距，后者是一种更实惠的技术，甚至可以在导管过程中使用，以优化注射的90y活性。
The purpose of the study is to evaluate whether a pinhole collimator is better adapted to bremsstrahlung single photon emission computed tomography [SPECT] than parallel-hole collimators and in the affirmative, to evaluate whether pinhole bremsstrahlung SPECT, including a simple model of the scatter inside the patient, could provide a fast dosimetry assessment in liver selective internal radiotherapy [SIRT]. Bremsstrahlung SPECT of an abdominal-shaped phantom including one cold and five hot spheres was performed using two long-bore parallel-hole collimators: a medium-energy general-purpose [MEGP] and a high-energy general-purpose [HEGP], and also using a medium-energy pinhole [MEPH] collimator. In addition, ten helical MEPH SPECTs (acquisition time 3.6 min) of a realistic liver-SIRT phantom were also acquired. Without scatter correction for SPECT, MEPH SPECT provided a significantly better contrast recovery coefficient [CRC] than MEGP and HEGP SPECTs. The CRCs obtained with MEPH SPECT were still improved with the scatter correction and became comparable to those obtained with positron-emission tomography [PET] for the 36-, 30- (cold), 28-, and 24-mm-diameter spheres: CRC = 1.09, 0.59, 0.91, and 0.69, respectively, for SPECT and CRC = 1.07, 0.56, 0.84, and 0.63, respectively, for PET. However, MEPH SPECT gave the best CRC for the 19-mm-diameter sphere: CRC = 0.56 for SPECT and CRC = 0.01 for PET. The 3.6-min helical MEPH SPECT provided accurate and reproducible activity estimation for the liver-SIRT phantom: relative deviation = 10 ± 1%. Bremsstrahlung SPECT using a pinhole collimator provided a better CRC than those obtained with parallel-hole collimators. The different designs and the better attenuating material used for the collimation (tungsten instead of lead) explain this result. Further, the addition of an analytical modeling of the scattering inside the phantom resulted in an almost fully recovered contrast. This fills the gap between the performance of90Y-PET and bremsstrahlung pinhole SPECT which is a more affordable technique and could even be used during the catheterization procedure in order to optimize the90Y activity to inject.