• Progress in Medical Physics
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• v.13 no.3
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• pp.163-168
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• 2002

As for planning the radiation therapy for the tumor in the lung, inferring the motion of the organ or target due to the respiration from the motion of the skin was performed as the feasibility study with the animal. The dog weighed 20 kg was chosen for the experiment. The system, which can use the fluoroscopy and the CCD camera synchronously, was designed. With a radio-opaque marker on the skin of the dog, which indicates the lower lobe of the lung, the images of the motions for the lung were recorded in the A/P (anterior-to-posterior) and lateral view. At the same time, the images of the skin motions from CCD camera were also recorded. Skin moves periodically with the amplitude of 6 mm and the target in the lung made almost the same frequencies during its motion's amplitude of 15 mm and its direction change with the respiration. Therefore analyzed results showed strong correlation between the skin motion and the organ motion on the average of 0.85. This study indicated that the prediction of a target position in the lung, which is moving organ, is possible. For the animal study, predicting the exact target motion from the skin motion was possible and it can have the feasibility to apply to the patient clinically.

• Progress in Medical Physics
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• v.22 no.3
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• pp.140-147
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• 2011

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 $1.59{\times}2.50mm$. 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.