Background : There are three ways to protect yourself from the danger of radiation, namely by regulating the length of irradiation (the effect of time), the use of anti-radiation material (shielding), and adjusting the distance from the radiation source (distance). In order to be safe in carrying out x-ray irradiation, patients and operators must take three steps so that radiation hazards can be minimized (Nunung, 2004). One way to check the danger of external radiation is to use a radiation barrier. This method is generally preferred, because it creates safe working conditions. Besides that the time and distance factors can be monitored continuously at the time of work, so that radiation workers can be guaranteed safety. Methods: This research is quantitative research with an experimental approach. The method of data collection in this study is observation, direct experiments and documentation. The types of sand to be used in this study are south beach sand, opaque sand, progo sand, white mountain sand and volcanic sand. Result : Concrete using sand material from South Beach has the lowest HVL value of 0.8644cm. Conclusion :The HVL value possessed by concrete with South Beach sand material is most effective in resisting x-ray radiation.

No abstract

MRI examination is one of the medical supports to assess the structure and anatomy of vertebrae thoracal. The modality that can be used is low field MRI. The disadvantages are produces low signals and noise. If the signal is low and the noise is high then the SNR value is low. The denoising technique is the right solution to remove noise. The BM3D denoising technique is able to reduce noise and increase the SNR. Aim to analyzing differences in image quality on Thoracal MRI images; study on low field MRI before and after the application of BM3D denoising techniques. This method is a quasi experimental research on Thoracal MRI images before and after the application of BM3D denoising techniques, totaling 15 samples. BM3D denoising was performed as well as assessment of Thoracal MRI images, including SNR and CNR. The Results is there are differences in SNR and CNR on Thoracal MRI images; study in low field MRI before and after the application of the BM3D denoising technique with p-value <0,001 and <0,001. The Conclusion is the BM3D denoising technique is able to improving image quality on thoracic MRI images; studies on low-field MRI.

Backgroud: T2 Weighted Image Turbo Spin Echo Short Tau Inversion Recovery (T2 TSE STIR) is a sequence to get the image pathologic which can reveal of tissue along surrounding pathology with fat suppresion technique. T2 Weighted Image Turbo Spin Echo Dixon is a sequence to get the image pathologic whic can reveal of tissue along surrounding pathology with fat and water suppresion technique. Based on observations at Dr. Hasan Sadikin Bandung Hospital, in the examination of MRI Lumbal using T2 TSE sequence with Dixon fat suppresion technique, while according to The American College of Radiology (2012), using STIR fat suppresion technique. The purpose of this research was to know the difference of information diagnostic image that is produced between T2 TSE STIR and T2 TSE Dixon sequences on the examination of MRI lumbal sagittal slice with Radiculopathy case. Methods: This research of type is experiment. The study was conducted with a 1,5 Tesla MRI at Installation Radiology of General Hospital Dr. Hasan Sadikin Bandung. The research took from of the 22 images of MRI lumbal sagittal slice from T2 TSE STIR and T2 TSE Dixon sequences with Radiculopathy cases. Assesment of the image was done by two respondents and Kappa test was conducted. Furthermore, the results of respondents assessment was analyzed by Wilcoxon different test. Results: The results showed that the research result Ho rejected and Ha accepted which mean there is a differences of information diagnostic image between T2 TSE STIR and T2 TSE Dixon sequences on the examination of MRI lumbal sagittal slices with Radiculopathy case with p value = 0,001 (p <0,05). Conclusion: T2 Sequence TSE Dixon can produce MRI images with more specific and homogeneous fat suppresion, thus providing more informative diagnostic information than T2 TSE STIR sequences.

Radiation protection is one of the external radiation protection efforts. Concrete is the material for making external radiation shields other than lead, steel, and other heavy materials. According to [2], concrete material for a good radiation shield is made from sand from the south coast of Yogyakarta with an average linear attenuation coefficient value of 0.801697695 cm^(-1) and an HVL value with an average of 0.865070204 cm. Therefore, this study aimed to determine the consistency of sand from Parangtritis beach to Congo beach influencing the linear attenuation coefficient of radiation shielding concrete.The research used is to use a sample of beach sand moulded into concrete with a size of 20 cm^2 with a thickness of 5 cm and then mixed. Data analysis was carried out using the equation Dx = Do.e-µx to get the linear attenuation coefficient value. The data obtained are compared to determine the consistency of beach sand in affecting the linear attenuation coefficient of radiation shielding concrete.The study's results showed that the highest liner attenuation coefficient was produced by concrete with the primary material of Trisik beach sand with a value of 1.314044724 cm^(−1). On the other hand, the lowest linear attenuation coefficient value is produced by concrete based on Parangtritis beach sand with a value of 0.939604673 cm^(-1), so that beach sand from Parangtritis beach to Congo beach does not have consistency in influencing the attenuation coefficient of the antiradiation concrete liner.