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New RF Hazards Class

Arizona and several other states have an occupational exposure standard for radiofrequency radiation sources. The standard, and requirements for the registration and survey of RF emitting sources are buried in an obscurely worded section of the radiation control regulations. At the completion of the class, safety managers should understand the RF radiation hazards and the specific requirements under the existing statutes for the management of radiating sources. The class covers the following topics:

The electromagnetic spectrum

Characteristics of RF radiations

Units used to measure non-ionizing radiations

Common sources

Calculation of radiated fields based on transmitter power and antenna gain

Biological Effects

Review of the frequency dependent exposure standards

Measurement tools for RF radiations

Examples of hazard evaluations using calculations and measurements.

The class is available in-person and online via Zoom or Microsoft Teams. Contact the office at (480) 897-9459 or (800) 477-8691 for more information.

New Dates for the Online RSO Course & Weekly Zoom Sessions

Online classes are now scheduled for October 17 – 19, 2022, December 5 – 8, 2022, and February 13 – 16, 2023. The online course is a hybrid course with both pre-recorded lectures, and live Zoom sessions for question and answer and problem solving. Students may work through the course materials and labs at their own pace. The course is well suited for students who have a disrupted work environment.

Many students are unable to attend the course at the established dates due to work issues and travel restrictions. These students are working their way through the materials at their own pace. To ensure that we are available to answer questions and work through problems, we have established weekly Zoom sessions on Wednesdays at 9 AM MST. Invitations for these sessions have been sent out to registered students. All students, of course, can send in email questions to either of the instructors at any time.

The regulatory authorities have offered some regulatory relief for licensees that are unable to complete their mandated tests and surveys in a timely manner due to the COVID-19 related shutdowns and and work disruptions. The documents to take advantage of these changes are provided as part of the course.

Online RSO Course

The RSO course is now available in an online format using prerecorded lectures and live Zoom sessions for question and answer and problem solving.   All of the laboratories have been converted to a virtual format and are included. The first offering of the online course was favorably received, so the course will continue to be offered in the online format. In-person classes will resume when the restrictions on such offerings are lifted.   The certificates for the online course are issued after the multiple choice tests are completed and graded. The class may be completed between established class offerings by working through the prerecorded lectures and labs in a self-paced fashion.  To accommodate students who are working through the material in this fashion, and those who could not complete the work in the four day established class period, we have established weekly Zoom meetings on Wednesdays at 9 AM MST for questions and problem solving.

If you wish to take the online RSO class, please contact the office at (480) 897-9459 to have all of the course materials, handouts, and tests sent to you before the class date.

Electronic Data Deliverable

All Radiochemistry lab results are now available in electronic form, if requested. The electronic format we use is a Excel Spreadsheet based on the EPA Manual entitled “Electronic data Deliverable (EDD) Comprehensive Specification Manual 4.0” dated March 2016. Call with any questions.

Two Papers Published in the Journal of Radioanalytical and Nuclear Chemistry

Two papers in J. Radioanalytical and Nuclear Chemistry were just published by Dr. Metzger and his colleagues.  The first paper covers the measurement and the dosimetry of long-lived contaminants in cyclotron produced radiopharmaceuticals.  The second describes the interaction these contaminants have with the ubiquitous homeland security radiation monitors and their potential impact for patients who have had diagnostic studies.

The links to the papers are:

https://rdcu.be/18yH       and

https://rdcu.be/2bV2

 

Head and Neck Doses from Advanced Cardiac and Interventional Radiology Procedures

There has been a tremendous technological advancement in life-saving cardiac and interventional radiology procedures performed under fluoroscopic guidance. These procedures, such as TAVRS (see https://www.youtube.com/watch?v=csxJYTLXNJY), provide life-saving benefits to the patients, but can be long and complex, and result in high radiation doses to the cardiologists and radiologists performing the procedures. Doses to the head and neck, which are outside of the protective lead apron, are monitored with a collar badge attached to the top of the apron. These badge results are now over 1 rad per month in many institutions, and are climbing due to the demand for these new procedures.

The most sensitive organ in the head and neck is the lens of the eye, where radiogenic cataract formation can occur after a threshold dose is received. The current limit for eye dose is 15 rads per year, which is based on a threshold dose of 500 rads for cataract formation. Recent epidemiological studies suggest that the actual threshold is less than 500 rads, and the International Commission on Radiological Protection (ICRP) has recommended a lower threshold dose, and head and neck limit. Forcing the dose lower by regulatory means is not desirable, as any adversarial regulatory action that reduced the availability or accessibility to the new life-saving procedures would necessarily cost human life in the vulnerable patient population. A shielding plan to protect the cardiologists and interventional radiologists is needed.

The only shielding available to the cardiologists and radiologists are various types of shadow shields which must be positioned correctly to reduce the head and neck dose. While essentially all hospitals and outpatient clinics equipped with cath labs to perform these procedures offer some kind of shadow shielding, it is only rarely positioned and used optimally.

Dr. Metzger has produced a Monte Carlo model of a cath lab and a special procedures room that allows the efficacy of the various shadow shields available in a facility to be evaluated prior to a specific procedure. The dose reduction possible with each shadow shield and any combination of the shields can be modeled and determined before the start of the procedure.

The paper describing this model can be found here, and will be presented at the Health Physics Society Midyear Meeting in San Diego, CA  (https://hps.org/meetings/meeting49.html).

New Ge-68 Breakthrough Test for Ge-68/Ga-68 Generators

Ga-68 for PET imaging is now available in a generator form from Eckert and Ziegler. As with all generators, there is always a possibility of some of the radionuclide held on the column (Ge-68) breaking through into the eluate (Ga-68) needed for imaging. A breakthrough test is needed with a limit of 0.001% or less of the Ge-68 parent in the Ga-68 eluate.  We have recently developed an inexpensive test using high resolution gamma spectroscopy. Call for more details.

Long-Lived Contaminants in Cyclotron-Produced Radiopharmaceuticals – Measurement

Long-lived contaminants are introduced into cyclotron produced radiopharmaceuticals from the activation and spallation of elements in the HAVAR target window into the target water.  They are removed during the synthesis of the final imaging agent.  Below, are a series of papers on the measurement of these contaminants, their retention in the body, and the dose delivered to the patient from them.  The quantity of the contaminants is strictly controlled by the FDA  which requires all drugs be 99.5% pure.  The vast majority of prepared radiopharmaceuticals have only a tiny fraction of the allowed levels in them.  The radiation dose these contaminants deliver to the patient, if present, is trivial.

They do, however, outlive the imaging isotope (typically F-18) and may alarm Homeland Security detectors found in many locations. The length of time these isotopes can alarm the detectors will be determined and published in the near future.

New method to detect and quantify contaminants

Keith Eckerman and Richard Leggett have provided uptake retention functions for soluble injected forms of each possible contaminating isotope and these tables are also presented in the link above.