(13.7)

and the pulse-height window. Quantitative measurements such as SUV may be inac­curate due to scatter coincidences.

In the convolution method, a scatter function is measured from a point source, which is then used to convolve with the source distribution to estimate the scatter data. An iterative method is used, whereby the scatter estimate is improved after each iteration. The scatter estimate is then subtracted from the image data. The method takes into account the scatter dependence on the position of the organ and detection angle, and is computationally efcient.

As mentioned before, normalization corrects for nonuniformities in the acquired PET data. It is accomplished by using a standard 20-cm long cylinder containing 1–3 mCi (37–111 MBq) 68Ge activity accurately positioned at the center of the FOV.All detectors are uniformly exposed to radiation in the absence of any object in the FOV.From the acquired 2-D or 3-D data, the correction factors are calculated for each detector by dividing the average counts of all detector pairs by each indi­vidual detector pair count (i.e., along the LOR; (Eq.13.3)). These factors are saved and later applied to corresponding detector pairs in the acquired emission data of the patient (Eq. 13.4). Usually, normalization factors need to be taken weekly or monthly, although some manufacturers recommend quarterly. For better statistical accuracy, long hours of counting (6–8 h) are necessary, and often, overnight data acquisition is made. Data acquisition and calculation of normalization factors and their storage are carried out by the manufacturer’s menu-driven software.

and personnel working in the facility. A nuclear medicine facility needs to apply to one of these organizations for accreditation submitting all required data and infor­mation along with appropriate fees. If satised upon proper scrutiny of the applica­tion, the organization grants accreditation to the nuclear medicine facility. The entire department or a specialty section of the department such as nuclear cardiol­ogy can apply separately for accreditation, provided it fullls the requirements. Although the goal of both organizations is the same, but there are differences in their requirements and standards for accreditation. The ICANL has two standards for nuclear laboratories: (1) Nuclear Medicine including PET and (2) Nuclear Cardiology. A facility can be a single site or a conglomerate of many sites under the same management. The ICANL requires a medical director who is an authorized user by an Agreement State or the NRC and a licensed and board certied nuclear physician with sufcient knowledge in administration, nuclear medicine technology and patient care. A technical director is also required by the ICANL for accredita­tion, who must be board-certied and licensed and has sufcient knowledge in tech­nology and patient care. All other physicians, technologists, medical physicists, and nuclear pharmacists must be board-certied in their respective profession or have sufcient training and experience. All professionals must obtain continuing educa­tion as frequently as required by the ICANL.The types of board certication and specic requirements for continuing education are available on www.icanl.org.

Protocols must be established in writing about general activities as well as clini­cal procedures in compliance with the NRC and Agreement State regulations and must be updated at least annually. Similar protocols must be established for the quality control of equipment used in the facility. Instruments must be in good work­ing condition, checked routinely for proper functioning, and records must be kept on le. The ICANL recommends that at least 600 studies be performed annually at each facility to maintain prociency in study interpretation and performance. In the application, one needs to submit a certain number of case studies for each category such as brain PET, cardiac PET, cardiac SPECT, other general nuclear medicine, etc. The specic number of normal and abnormal cases required for submission in the application is available at www.icanl.org. The quality control data of equipment and phantom images also need to be submitted, along with various protocols for patient studies and applicable fees. An agreement by the medical director to follow the terms and conditions of the ICANL must accompany the application. The ICANL can make a random visit to verify the compliance of the facility with the commitment made in the application. Accreditation is granted for 3 years and is renewable upon reapplying with the required information.