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Instrumentation & Data Analysis: InstrumentationInstrumentation Posters |
1 Hokkaido University, Sapporo, Hokkaido, Japan; 2 Hitachi Ltd. Central Research Laboratory, Hitachi, Ibaraki, Japan
1712
Objectives: Intensity-modulated radiation therapy is an advanced mode of high-precision radiotherapy to deliver precise radiation doses to specific areas within the tumor and has become popular in clinical situation. It becomes more important to estimate intratumoral cell activity. We developed a new PET with CdTe detectors which provides images with high resolution and low scatter noise. Phantom images and patient images were both analyzed to evaluate intratumoral cell activity for clinical use.
Methods: This study was performed utilizing a cold spot phantom with 6 and 10 mm diameter cold sphenoid defects. Those were surrounded water. The cold spot phantom images and FDG-PET images of the patients suffering with nasopharingeal cancer were compared with a conventional BGO PET scanner (Siemens HR+). Profile curves of the phantom were measured in order to define the contrast as peak to valley ratio.
Results: The transverse resolutions at the center are 2.3 mm. The contrast of 10mm sphenoid cold phantom increased by 179% in the new PET (4.19) compared with conventional PET (2.34). The contrast of 6mm sphenoid cold phantom increased by 127% in the new PET (1.53) compared with conventional PET (1.20). New PET identified intratumoral inhomogeneous glucose metabolism more in detail than conventional PET in four out of ten patients with nasopharyngeal cancer.
Conclusions: These phantom and clinical studies suggested that this new PET has a potential for better identification of intratumoral inhomogeneous cell activity probably due to higher spatial resolution with less scatter noise.
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