This article presents the protocol on Quality Controls in PET/CT and PET/MRI published online in May 2022 by the European Federation of Organisations for Medical Physics (EFOMP), which was developed by the Working group for PET/CT and PET/MRI Quality Control (QC) protocol. The main objective of this protocol was to comprehensively provide simple and practical procedures that may be integrated into clinical practice to identify changes in the PET/CT/MRI system's performance and avoid short- and long-term quality deterioration. The protocol describes the quality control procedures on radionuclide calibrators, weighing scales, PET, CT and MRI systems using selected and measurable parameters that are directly linked to clinical images quality. It helps to detect problems before they can impact clinical studies in terms of safety, image quality, quantification accuracy and patient radiation dose. CT and MRI QCs are described only in the context of their use for PET (attenuation correction and anatomical localization) imaging. Detailed step-by-step instructions have been provided, limiting any misinterpretations or interpersonal variations as much as possible. This paper presents the main characteristics of the protocol illustrated together with a brief summary of the content of each chapter. A regular QC based on the proposed protocol would guarantee that PET/CT and PET/MRI systems operate under optimal conditions, resulting in the best performance for routine clinical tasks.
Retinal oximetry imaging of retinal blood vessels measures oxygen saturation of hemoglobin. The imaging technology is non-invasive and reproducible with remarkably low variability on test-retest studies and in healthy cohorts. Pathophysiological principles and novel biomarkers in several retinal diseases have been discovered, as well as possible applications for systemic and brain disease. In diabetic retinopathy, retinal venous oxygen saturation is elevated and arteriovenous difference progressively reduced in advanced stages of retinopathy compared with healthy persons. This correlates with pathophysiology of diabetic retinopathy where hypoxia stimulates VEGF production. Laser treatment and vitrectomy both improve retinal oximetry values, which correlate with clinical outcome. The oximetry biomarker may allow automatic measurement of severity of diabetic retinopathy and predict its response to treatment. Central retinal vein occlusion is characterized by retinal hypoxia, which is evident in retinal oximetry. The retinal hypoxia seen on oximetry correlates with the extent of peripheral ischemia, visual acuity and thickness of macular edema. This biomarker may help diagnose and measure severity of vein occlusion and degree of retinal ischemia. Glaucomatous retinal atrophy is associated with reduced oxygen consumption resulting in reduced arteriovenous difference and higher retinal venous saturation. The oximetry findings correlate with worse visual field, thinner nerve fiber layer and smaller optic disc rim. This provides an objective biomarker for glaucomatous damage. In retinitis pigmentosa, an association exists between advanced atrophy, worse visual field and higher retinal venous oxygen saturation, lower arteriovenous difference. This biomarker may allow measurement of severity and progression of retinitis pigmentosa and other atrophic retinal diseases. Retinal oximetry offers visible light imaging of systemic and central nervous system vessels. It senses hypoxia in cardiac and pulmonary diseases. Oximetry biomarkers have been discovered in Alzheimer's disease and multiple sclerosis and oxygen levels in the retina correspond well with brain.
- MeSH
- kyslík krev MeSH
- lidé MeSH
- mozkový krevní oběh fyziologie MeSH
- nemoci mozku diagnostické zobrazování patofyziologie MeSH
- nemoci retiny diagnostické zobrazování patofyziologie MeSH
- oxymetrie * MeSH
- retinální cévy patofyziologie MeSH
- zraková ostrost MeSH
- zraková pole MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
