Development and comparison of spine-shaped phantoms generated by two different 3D-printing technologies, digital light processing (DLP) and Polyjet has been purposed to utilize in patient-specific quality assurance (QA) of stereotactic body radiation treatment. The developed 3D-printed spine QA phantom consisted of an acrylic body phantom and a 3D-printed spine shaped object. DLP and Polyjet 3D printers using a high-density acrylic polymer were employed to produce spine-shaped phantoms based on CT images. Image fusion was performed to evaluate the reproducibility of our phantom, and the Hounsfield units (HUs) were measured based on each CT image. Two different intensity-modulated radiotherapy plans based on both CT phantom image sets from the two printed spine-shaped phantoms with acrylic body phantoms were designed to deliver 16 Gy dose to the planning target volume (PTV) and were compared for target coverage and normal organ-sparing. Image fusion demonstrated good reproducibility of the developed phantom. The HU values of the DLP- and Polyjet-printed spine vertebrae differed by 54.3 on average. The PTV Dmax dose for the DLP-generated phantom was about 1.488 Gy higher than that for the Polyjet-generated phantom. The organs at risk received a lower dose for the 3D printed spine-shaped phantom image using the DLP technique than for the phantom image using the Polyjet technique. Despite using the same material for printing the spine-shaped phantom, these phantoms generated by different 3D printing techniques, DLP and Polyjet, showed different HU values and these differently appearing HU values according to the printing technique could be an extra consideration for developing the 3D printed spine-shaped phantom depending on the patient’s age and the density of the spinal bone. Therefore, the 3D printing technique and materials should be carefully chosen by taking into account the condition of the patient in order to accurately produce 3D printed patient-specific QA phantom.

Stent-shaped multi-PDO scaffolds may be another effective and safe treatment modality for reduction of forehead wrinkles.

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A respiratory motion during whole-body imaging has been recognized as a source of image degradation and induces distortions in Positron Emission Tomography (PET) study. The aim of this study is to evaluate respiratory motion using lung simulator and to develop a respiratory motion detecting system using optical laser sensor. We utilized a commercially available laser optical sensor to detect respiratory motion during PET scanning. Each respiratory cycle is divided into 4 bins defined as average peak interval and irregular peak within the patient's breathing motion. The acquired data within the time bins correspond to different positions within the breathing cycle and stored for the post motion correction. Artifact of breathing motion was evaluated with the phantom study. In the images of a human subject, the blurring artifact due to breathing motion was divided by our detecting system. This technique improves the quantitative specific activity of the tracer which is distorted by the respiratory motion.