The Centiloid Project aims to standardize quantitative amyloid plaque estimation using PET. The study addresses the variability in quantitative outcomes from different PET tracers and analysis methods. A working group developed a method to scale results from any PET analysis to a 0-100 scale, anchored by young controls (≤45 years) and typical Alzheimer's disease (AD) patients. This scale, called "Centiloids," allows for consistent comparison across studies and sites. The project involved defining anchor points for the scale using PiB PET data from 34 young controls and 47 AD patients. The study also outlines a standard method for analyzing PiB PET data and a process for scaling non-standard methods to the Centiloid scale. The approach uses a unified segmentation method for normalization and defines reference regions for analysis. The study provides detailed procedures for data collection, normalization, and analysis, and makes all data available for unrestricted use. The Centiloid method enables direct numeric comparisons across different measures and facilitates the application of universal cutoffs between normal and abnormal ranges. The study also describes how to calibrate new methods to the Centiloid scale, including the use of F-18 tracers when necessary. The results demonstrate the effectiveness of the Centiloid method in standardizing amyloid PET data and improving the comparability of results across different studies and sites.The Centiloid Project aims to standardize quantitative amyloid plaque estimation using PET. The study addresses the variability in quantitative outcomes from different PET tracers and analysis methods. A working group developed a method to scale results from any PET analysis to a 0-100 scale, anchored by young controls (≤45 years) and typical Alzheimer's disease (AD) patients. This scale, called "Centiloids," allows for consistent comparison across studies and sites. The project involved defining anchor points for the scale using PiB PET data from 34 young controls and 47 AD patients. The study also outlines a standard method for analyzing PiB PET data and a process for scaling non-standard methods to the Centiloid scale. The approach uses a unified segmentation method for normalization and defines reference regions for analysis. The study provides detailed procedures for data collection, normalization, and analysis, and makes all data available for unrestricted use. The Centiloid method enables direct numeric comparisons across different measures and facilitates the application of universal cutoffs between normal and abnormal ranges. The study also describes how to calibrate new methods to the Centiloid scale, including the use of F-18 tracers when necessary. The results demonstrate the effectiveness of the Centiloid method in standardizing amyloid PET data and improving the comparability of results across different studies and sites.