Frequently Asked Questions

The Clinical Trials Network strives to provide the community with as much information as possible within the context of this website on its projects, programs and overall goals. Often, some questions or topics require additional clarification or facts, which we address through this Frequently Asked Questions page. We realize, however, that there still may be some areas in which the public would like additional information. If your question was not answered on our website or the main SNMMI website, please complete the FAQ form. We will reply as soon as possible and, depending on its question, may add it to our FAQ page.


Education Program 

Q.   Why does the CTN have its own separate Education Program?

A. The CTN Education Program is part of the SNMMI program and offers the same credits. The courses, however, are focused on molecular imaging in clinical research. 


Q.   What types of courses are offered? 

A. The CTN has courses that cover basic, intermediate and advanced topics on performing clinical research in general and as it applies to PET imaging. The curriculum consists of courses and webinars, most of them presented live and then recorded.


Q.   I missed a webinar that the CTN presented. Are webinars also available for purchase?

A. Yes, live webinars are recorded and then made available for purchase a few days after the live presentation.


Q.   Are there continuing credits offered for courses?

A. Yes, most courses offer both VOICE and CME credits.  Some also offer CAMPEP credits.


Q.   How much do the courses cost?

A.    The courses are priced so that as many people as possible can take advantage of them. Member technologists pay $20/course and non-members pay $32. Member physicians and scientists pay $29/course and non-members pay $49. There are also combination pricing options.


Q.   I would like to have a number of my employees take certain courses offered by the CTN. Is there a discount if we purchase more than one copy of one course or a number of different courses?

A. Please contact the CTN for a customized price to meet your needs.


Q.   How do I access the list of the available courses or webinars?

A. The list of courses and webinars are available through the SNMMI Learning Center. Just log in with your SNMMI member ID and select the item(s) listed under the Clinical Trials Network offerings.


Q.   Are there any courses that apply to sites outside of the United States?

A. The CTN is currently developing courses that apply to regulations and procedures that are outside of the US. We hope to have some recorded and available for purchase in the coming year.


Q.   I would like to help write or present a topic for a webinar or course. How do I become involved in the CTN Education Program?

A. Please contact the CTN by sending an email to


Scanner Validation & Site Qualification Program

Q.   Why should I validate my PET/CT scanner?

A. PET/CT scanners used in multi-center research should be validated to ensure that study images are standardized across all sites. It is vital that multi-center studies be conducted in a standardized fashion to facilitate accurate interpretation of the study data. Standardization of imaging data in multi-site clinical trials leads to improved efficiency and validity for using imaging biomarkers in therapeutic trials.


Q.   What does scanner validation involve?

A. Imaging sites first complete a scanner questionnaire that includes the make/model of scanners and dose calibrators. Sites approved to proceed are sent a CTN phantom with email instructions on filling and scanning the phantom. Once acquired, the phantom images are uploaded into the CTN central server for review, and sites email the completed worksheets to the CTN. A panel of trained reviewers analyzes the images and the data to determine if they meet pre-determined minimum requirements regarding lesion detectability, image quality and SUV measurements. When the site passes this first step, it must then complete and submit an SUV measurement worksheet. If SUV measurements are within the acceptable range, the site is notified that it has met all the required elements for scanner validation and receives a certificate for each scanner validated.


Q.   How long does the validation process take?

A. The validation process takes several hours of staff time over the course of several days. The total amount of time is dependent on how soon the site can get available scanner time and the FDG dose, scan the phantom and complete the worksheets, and then submit all data and images to the CTN for review. Once the images are uploaded, the CTN will complete its initial review within 48 hours.  At this time any major problems will be addressed and communicated with the site. The entire Scanner Validation Process takes about 21 days. 


Q.   What happens if our scanner does not pass validation?

A. If the measurements or images do not pass, the CTN reviewer recommends possible options to improve the area where errors were found. If a site does not pass after 2 attempts, the site may need to make adjustments to the scanner – which may include vendor assistance, general maintenance and/or new equipment – before another attempt is performed. In some cases, a scanner may never successfully pass validation due to age, problems with the dose calibrator or overall poor image quality, and the scanner would not be considered validated for use in research studies. 


Q.   If our site has more than one PET/CT scanner, do all of them have to pass validation?

A. If a site has more than one PET/CT scanner, one may be validated while the other may not pass. Only one scanner needs to be validated for a site to be qualified, as long as the validated scanner is the one used for clinical research.


Q.   Is there a cost to use the CTN phantom to become validated under the Clinical Trials Network?

A. Yes, please refer to PET/CT Scanner Validation Program Informational Flyer for more information. The phantom will be provided to your site for validation tests, and then you will return it to the CTN. The CTN now has chest phantoms available for purchase. Emails may be directed to Shyanne Mortimer at


Q.   Can a site purchase the CTN phantom?

A. There is no requirement to purchase the phantom for the validation exercise. However, special phantoms that a site can keep at their location for training and testing purposes are available for purchase.


Q.   Are centers outside the United States encouraged to participate?

A. All clinical research PET imaging centers are encouraged to register with the CTN and complete the scanner validation process. Many of our industry sponsors use sites in foreign countries for their studies and often ask the CTN for a list of the validated scanners. Aside from possible delays related to international shipping, the process is for validating scanners is the same throughout the world.  


Q.   What does site qualification involve?

A. A qualified site is one that has successfully completed the scanner validation process AND completed all the required information in our database. 


Q.   Can a site be qualified if it doesn’t complete the additional information on site personnel, research infrastructure, experience and availability of radiopharmaceuticals?

A. No. There is a minimum of information required from the site before it can be considered for qualification.


Q.   If our site becomes qualified, will we automatically be included in a research study?

A. No. The CTN only provides a list of qualified sites to our sponsoring partners. The study sponsor decides which sites to use for their trial based on the study parameters, patient availability and imaging agent logistics.


Q.   Can a site be qualified if site personnel have no experience in PET imaging research?

A. Although helpful, a site does not have to have experience in PET imaging to participate in clinical research studies. If a site has personnel, such as coordinators and nuclear medicine technologists, who have the time in their schedule and are willing to be trained in research practices and procedures, a site could still be qualified as long as all the other requirements are met. 


Q.   Once qualified, will a site have to undergo repeat qualification?

A. A site should expect to go through re-qualification on an annual basis, including scanner re-validation. In some cases, a site may be required to repeat certain tests depending on study-specific criteria or if significant upgrades to equipment and/or personnel occur during the year. In these cases, CTN staff works with the site to complete any necessary procedures to make sure a site remains qualified to participate in multi-center clinical trials.


Site Registry - CTN Database

Q.   What is the CTN Database?

A. The CTN database is a list of imaging and/or radiopharmaceutical production sites that have expressed an interest in participating in multi-center clinical trials. Sites are identified as being one of three categories: imaging site, production site or imaging and production site. You would select which group most appropriately describes your facility’s capabilities. The information provided by all sites is stored in a web-based database that industry sponsors can review when considering potential sites for their trials.


Q.   Is there a fee to register my site? If so, how much is it?

A. There is no fee to register your site with CTN at this time. 


Q.   How do I register my site?

A. If you would like to join the registry, click on the “Site Registry” page in the left navigation bar on the CTN website and follow the directions to register your site. CTN staff processes your email request internally and, once approved, sets up your site and provides you with access to enter your site's information.


Q.   Is there a deadline to register with the CTN?

A. No. Registration remains open indefinitely. We encourage interested sites to join the CTN at any time. 


Q.   Who has access to my information?

A. The information you enter about your site is available to our pharmaceutical and radiopharmaceutical developers who are interested in placing clinical trials at imaging sites. While this is a limited list of companies, and the database is password-protected, you should not enter data that you would be uncomfortable if others saw.


Q.   What if the information about my site changes after I have registered?

A. There are two ways to update your site's information in the CTN database. You can update your site's information yourself using the login and password provided when you site was set up or you can send CTN staff the updated information in an email to  


Q.   If I register my site, am I required to participate in clinical trials sponsored by drug developers?

A. Registration in the CTN does NOT obligate you to participate in any specific trials. However, only sites that have registered and have met CTN qualification requirements will be included in the list recommended sites that CTN provides industry sponsors.


Q.   How are sites selected for participation in any given multicenter clinical trial?

A. CTN recommends sites to industry sponsors based on the sponsor's study-specific parameters. However, final site selection is at the discretion of the sponsoring drug developer, and CTN cannot guarantee that your site will be selected.


Q.   What type of information is required about my site?

A. Depending on the category in which your site falls, different information may be required. Imaging sites enter data on PET scanner equipment (including the dose calibrator), experience of personnel involved in research imaging, radiopharmaceutical agents used at the site and research infrastructure. Production (manufacturing) sites provide information on their cyclotron, what they can manufacture and how often. If your site does both – clinical research imaging and radiopharmaceutical manufacturing – you must answer the questions pertaining to both categories.


Q.   What is required of registered sites?

A. Sites in the CTN database are encouraged to obtain full-CTN qualification, which includes undergoing successful PET/CT scanner validation.  To remain qualified, sites must undergo annual validation of PET/CT scanners with the CTN clinical phantom, update site information as circumstances or equipment changes – at least annually – and adhere to all GCP and federal regulations for performing clinical research.  


Q.   Do we have to be a PET imaging facility to register with the CTN?

A. CTNs mission includes the integration and standardization of ALL types of imaging into clinical trials, including SPECT, MR and CT. It is possible that, in the future, the CTN may be used to drive the standardization of multi-center imaging in clinical trials even where no radiopharmaceutical imaging agent is used (e.g., some MR studies). However, we do not have the ability to register non-PET facilities at this time.


Q.   Is it possible for imaging centers outside the US to register and participate in clinical research trials?

A. Yes, international participation is strongly encouraged. In fact, the pharmaceutical developers who have expressed interest in using the CTN to sponsor multi-center clinical trials have specifically requested significant international participation.


Q.   As a foreign PET/CT center, what would we need to do register our site?

A. Steps for inclusion in the registry are no different than for US sites. Click on the “Site Registry” page in the left navigation bar on the CTN website and follow the directions to register your site. CTN staff processes your email request internally and, once approved, sets up your site and provides you with access to enter your site's information.


Q.   Is international participation in studies different from US study centers?

A. All sites participating in a given trial must adhere to the same study imaging protocol and obtain the necessary regulatory approvals for that country. However, there may be barriers to participation in a given clinical trial based on country-specific regulations and the requirements of a study.  Each site would need to work with the study sponsor to overcome any such roadblocks. The process for CTN scanner validation and qualification is the same whether US based or in an international location.


Q.   Our site has provided radiopharmaceuticals for investigational studies and are cGMP compliant. We have extensive experience with RDRC committees, human use committees, pharmacy regulations, and FDA regulations. How can we help?

A. If you would like to be considered as a potential manufacturer of an investigational radiopharmaceutical for a future multi-center clinical trial, please register your site and complete all of the information related to your production capabilities.


Technologist Resources

Q.   Is clinical research the only topic in which the CTN offers guidance or assistance to nuclear medicine technologists? 

A. he CTN offers assistance through courses, webinars and presentations that primarily address performing imaging for clinical research studies. However, these topics vary and can include information on novel imaging agents, basic general research tips, scanner QC procedures and regulatory guidelines.  For the technologists, specifically, we have been working with the Tech Section leadership to present topics that help techs advance their careers in fields other than clinical imaging.


Q.   Does the CTN ever offer courses at the SNMMI Chapter meetings?

A. The CTN is currently working with leadership from each of the Chapters to identify a meeting date and time where the CTN can present a topic for regional technologists. Check the Meeting section on the CTN website for updated information.


Q.   How can I become involved in the work that the CTN does for the nuclear medicine technologists?

A. The CTN Site Education Committee always welcomes members who have the time and interest in helping to prepare high-quality educational materials for webinars, meeting sessions and publications. If you would like to learn more about the CTN Committees, please send us your contact information and your areas of interest in an email to


Centralized Radiopharmaceutical INDs 

Q.   Is the Clinical Trials Network solely about filing INDs for PET tracers?

A. No. The SNMMI Clinical Trials Network is dedicated to facilitating the use of ALL imaging agents in multi-center clinical trials of investigational therapeutics. This includes - but is not limited to - PET/CT, contrast agents for MRI, fMRI, CT and U/S, plus all optical imaging agents. If a non-PET agent is identified, the CTN will assist in securing imaging sites and manufacturers appropriate for the trial.


Q.   Is the SNMMI-held centralized IND available for single, investigator-initiated studies?

A. No. Currently, the SNMMI-held centralized IND can only be used for multi-center clinical trials


Q.   Is there a limit to the number of patients under the FLT IND?

A. FDA has not stipulated the total allowable number of administered doses for the F-18-FLT. For each protocol submitted under the IND, the number of patients receiving an FLT dose must be approved.


Q.   If I cross-reference an SNMMI-held IND, will the study information be available to others?

A. No, only FDA reviews the study data collected in any clinical trial under our IND. The CTN only collects data directly relevant to overseeing its IND, such as imaging-related acquisition information, compliance/QC and safety reports.


Q.   Under the SNMMI centralized FLT IND, does the CMC specify a specific precursor for the F-18-FLT manufacturing process?

A. No. There are multiple manufacturing processes included under the IND.


Q.   I understand the FDA is using a new endpoint specification review process with this IND. Will every manufacturing site still have to submit their CMC?

A. Yes, all manufacturers of FLT being administered to subjects under the SNMMI's centralized IND must provide CMC information for FDA review.


Q.   Are there FLT QC release specifications in the SNMMI IND that need to be met by each site? 

A. Yes. There release criteria specified in the FLT IND. However, if a manufacturer plans to use different criteria, the FDA has agreed to review these specifications first.


Q.   Since manufacturers must submit CMC specifications, will the FDA base its review on the CMC process or on the final formulation?

A. The FDA addressed formulation by stating it will review the specifications of the final product to be administered to subjects. The FDA requires specification for their review on the final product (formulation) to be administered to subjects. The review process is NOT based solely on the CMC process.


Q.   If I participate as a manufacturer in a trial, will SNMMI share my CMC information, or will my CMC information be available for others to see?

A. No, only the FDA will see your CMC information.


Q.   If a letter of cross-reference is granted between a Drug Master File and the SNMMI when using the FLT IND, can the SNMMI review the details of the DMF?

A. To meet the FDA manufacturing standards under the SNMMI-held FLT IND, an FLT manufacturer must submit to the FDA detailed information related to chemistry, manufacturing and controls (CMC), as well as pharmacology and toxicology information. Only FDA has access to this information. When a DMF approach is used, two letters of cross-reference are required. First, the manufacturer must provide the SNMMI with a letter to allow cross-referenced use of their DMF in writing. Second, each imaging site must have a letter of cross-reference from the commercial manufacturer that states the supplier will provide FLT in accordance with the DMF that has been approved. The site must provide that letter to the SNMMI. In place of submitting the detailed information directly, a site can choose to purchase FLT from a commercial manufacturer with an approved Drug Master File (DMF) for FLT on file with the FDA.


Q.   Which commercial suppliers are approved to provide FLT under the SNMMI-held FLT IND?

A. The four largest suppliers of PET radiopharmaceuticals in the US: PETNet Solutions, IBA Molecular, Cardinal Health and University of Iowa, as well as the Biomedical Research Foundation and Children’s Hospital of Detroit (for Karmanos Cancer Center) provided the SNMMI with letters of cross-reference and have been approved by the FDA to produce FLT under the SNMMI-held centralized FLT IND.


Q.   Will the radiopharmaceutical used under a centralized IND still have to go through Phase 2 and 3 clinical trials to obtain an NDA?

A. FDA has not changed its processes for New Drug Applications. The burden is still on the filer to demonstrate safety and efficacy.


Q.   Where can I get additional information about submitting my site's CMC to the FDA?

A. You can contact the FDA directly with all questions by emailing