Effect of Harderian adenectomy on the statistical analyses of mouse brain imaging using positron emission tomography

Positron emission tomography (PET) using 2-deoxy-2-[18F] fluoro-D-glucose (FDG) as a radioactive tracer is a useful technique for in vivo brain imaging. However, the anatomical and physiological features of the Harderian gland limit the use of FDG-PET imaging in the mouse brain. The gland shows strong FDG uptake, which in turn results in distorted PET images of the frontal brain region. The purpose of this study was to determine if a simple surgical procedure to remove the Harderian gland prior to PET imaging of mouse brains could reduce or eliminate FDG uptake. Measurement of FDG uptake in unilaterally adenectomized mice showed that the radioactive signal emitted from the intact Harderian gland distorts frontal brain region images. Spatial parametric measurement analysis demonstrated that the presence of the Harderian gland could prevent accurate assessment of brain PET imaging. Bilateral Harderian adenectomy efficiently eliminated unwanted radioactive signal spillover into the frontal brain region beginning on postoperative Day 10. Harderian adenectomy did not cause any post-operative complications during the experimental period. These findings demonstrate the benefits of performing a Harderian adenectomy prior to PET imaging of mouse brains.

The Result of Minimal Invasive Anterior Lumbar Interbody Fusion with Posterior Lumbar Interbody Fusion on Degenerative Lumbar Flat Back Disease

STUDY DESIGN: Restrospective study. OBJECTIVES: We tried to find out the effects of minimal invasive anterior lumbar interbody fusion (ALIF) combined with posterior lumbar interbody fusion for degenerative lumbar flat back disease. SUMMARY OF LITERATURE REVIEW: ALIF combined with PLIF is effective in correcting lumbar lordosis. However, the complication rate with conventional ALIF is higher on the lower level. MATERIALS AND METHODS: 21 cases (9 men and 12 women, 46-83 years of age) of having undergone minimal invasive ALIF and PLIF due to degenerative flat back disease were reviewed. The follow-up period was an average of 23 months. We compared the pre-postoperative pain, the functional outcome, the correction of sagittal imbalance and lordotic angle. RESULTS: At final follow-up, 21 cases with the solid fusion experienced a great improvement in their lower back pain(VAS: 7.3 --> 2.6) and leg pain (VAS: 7.0 --> 2.7) and ODI(38.5 --> 18.1). And we experienced correction in sagital imbalance. On levels with anterior fusion, lordotic angle is corrected 6.3 degrees while on levels with posterior fusion, lordotic angle is corrected 9.7 degrees. Plumb line is corrected by 5.2cm, and no complication was found in the follow-up period. CONCLUSIONS: Combined surgery with minimal invasive anterior lumbar interbody fusion and posterior fusion is an effective procedure on patients who need long level surgery for correction of lumbar deformity and decompression.

Estimation of Internal Motion for Quantitative Improvement of Lung Tumor in Small Animal / 의학물리

The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was 1.59x2.50 mm. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.