Fractal analysis of neuroimaging: comparison between control patients and patients with the presence of Alzheimer’s disease

Alzheimer’s disease is a neurodegenerative cognitive, affective, and behavioral disorder aligned to the aging process and other coronary diseases. To contribute to the early diagnosis of the disease, a neuroimaging treatment is implemented through a preprocessing to subsequently calculate the fractal dimension associated with these images in order to propose an alternative to the one proposed in medical physics through positron emission tomography. In this work, a comparative analysis is made of a previous work using the Box Counting methodology versus the calculation of the fractal dimension by means of software developed by the researchers based on the same method. The differences between the fractal dimensions of the neuroimages of control patients and patients with the presence of the disease are maintained showing a lower value of fractal dimension in patients with the disease due to the physical deterioration of the brain.

Dosimetric Evaluation of a Treatment Planning System Using the Aapm Medical Physics Practice Guideline 5.a (MPPG 5.a) Validation Tests

In this work, the AAPM Medical Physics Practice Guideline 5.a (MPPG 5.a) validation tests package was used to evaluate the dosimetric performance of a new version of the Eclipse treatment planning system (TPS) algorithms. A series of tests were developed and comparisons between TPS calculated and corresponding beam data measurements have been performed for basic beam validation, heterogeneity correction and IMRT/VMAT dose validation tests. Measurements were performed using a Varian IX Linear Accelerator with the 6 MV, 6MV FFF and 18 MV photon beams, and 6, 9, 12, 16, 20 MeV electron beams. Results for basic dose validation tests yielded differences within 3% for all point doses and pass rate greater than 95% for all depth profiles using 3%/3mm criteria. For testing the ability of the TPS in accounting for tissue inhomogeneity, corresponding comparisons were performed with the presence of a heterogeneous media to simulate an air inhomogeneity. Results showed a mean deviation between the TPS calculated and measured of 1.9%, reaching a maximum of 2.8% for the AAA algorithm. For IMRT/VMAT validation tests, our local criteria passing rate of 95% was used, but no consensus of the tolerance exists. Our results agree well with the data reported accuracy in previous studies of Eclipse TPS. In summary, the AAPM MPPG 5.a validation tests are a valuable package for evaluating dose calculation accuracy and are very useful for TPS upgrade checks, commissioning tests and routine TPS QA.

Quality Assurance (Qa) Dan Quality Control (Qc) Cobalt

Cobalt-60 adalah instrumen radioterapi yang digunakan untuk mematikan sel tumor maupun kanker pada pasien. Untuk menjamin kualitas instrumen Cobalt, diperlukan QA (Quality Assurance) dan untuk membuktikan adanya jaminan kualitas perlu QC (Quality Control). Hal ini dilakukan bertujuan untuk memeriksa dan menguji data untuk menentukan standar dan mengecek kesesuaian produk mencapai operasi manufaktur yang maksimum atau ukuran yang diambil yaitu untuk menilai, merawat atau memperbaiki kualitas perlakuan yang diberikan. Program QA harus didasarkan pada penyelidikan menyeluruh untuk standar awal pada saat penerimaan dan commissioning peralatan untuk penggunaan klinis (AAPM, 1993a). International Electrotechnical Cornmission (IEC, 1989a, b), American Association of Physicists in Medicine (AAPM, 1984,1993a), dan American College of Medical Physics (ACMP, 1986) menjelaskan prosedur dan kondisi untuk tes penerimaan. Salah satu rangkaian QA QC adalah kalibrasi meliputi kalibrasi harian, mingguan, bulanan dan tahunan. Kalibrasi harian, mingguan dan bulanan dilakukan oleh fisikawan medis dengan dibantu radiografer, sedangkan kalibrasi tahunan dilakukan oleh pihak BATAN.

European consensus on patient contact shielding

Patient contact shielding has been in use for many years in radiology departments in order to reduce the effects and risks of ionising radiation on certain organs. New technologies in projection imaging and CT scanning such as digital receptors and automatic exposure control systems have reduced doses and improved image consistency. These changes and a greater understanding of both the benefits and the risks from the use of shielding have led to a review of shielding use in radiology. A number of professional bodies have already issued guidance in this regard. This paper represents the current consensus view of the main bodies involved in radiation safety and imaging in Europe: European Federation of Organisations for Medical Physics, European Federation of Radiographer Societies, European Society of Radiology, European Society of Paediatric Radiology, EuroSafe Imaging, European Radiation Dosimetry Group (EURADOS), and European Academy of DentoMaxilloFacial Radiology (EADMFR). It is based on the expert recommendations of the Gonad and Patient Shielding (GAPS) Group formed with the purpose of developing consensus in this area. The recommendations are intended to be clear and easy to use. They are intended as guidance, and they are developed using a multidisciplinary team approach. It is recognised that regulations, custom and practice vary widely on the use of patient shielding in Europe and it is hoped that these recommendations will inform a change management program that will benefit patients and staff.