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Session in Memory of Phil Heintz: Patient Dose Calculations in Imaging - Fluoro, CT, and Fetal

K Kanal1*, K Brown2*, W Sensakovic3*, S Brady4*, (1) University of Washington, Seattle, WA, (2) Penn State Milton S. Hershey Med Ctr., Hershey, PA, (3) Florida Hospital, Orlando, FL, (4) Cincinnati Childrens Hospital Med Ctr, Cincinnati, OH


(Monday, 7/30/2018) 4:30 PM - 6:00 PM

Room: Room 207

Patient dosimetry is an important skill for a Medical Physicist to have in their toolbox with medical physicists being called upon to estimate patient dose in several modalities. These inquiries may originate from patients, providers, or committees within an organization such an Institutional Review Board. Dose estimates may be used for quality assurance and improvement processes, protocol optimization, benchmarking, or patient risk estimates. In this session we will focus on CT, Fluoroscopy and fetal dosimetry.

CT - Dose metrics displayed on the CT scanner such as CTDIvol and DLP can be useful tools however each has limitations that must be understood in order to provide an appropriate dose estimate for the circumstance at hand. Evaluation of individual patient risk estimates often requires a more rigorous evaluation.

Fluoroscopy and Interventional Radiology - these machines have several modes of operation which create a wide range of dose rates. Further, the operators directly control the modality creating variability in exposure time and beam position. Interventional Radiology also has the unique issue of possibly creating tissue as well as stochastic effects. This necessitates an understanding of methods to calculate not only effective dose, but also surrogates for peak skin dose. This talk will review dose metrics and radiobiology relevant to the modality. Further, we will work through adult and pediatric dose calculations using a case-based approach.

Fetal dosimetry - Most imaging clinics have experienced the moment while reading an examination and realizing that the women was pregnant at the time of the exposure, or in some cases, a pregnant women presents with a clinical need for imaging while pregnant. In these examples, often times, the role of the medical physicist is to provide a risk assessment and general counsel to radiologists and/or hospital management. The goal of this educational talk is to provide a comprehensive review of scientific, regulatory, and educational material on the topic of fetal exposure (and risk calculation).

Learning Objectives:
1. Describe the limitations of displayed dose metrics for estimating patient dose
2. Review methods to estimate effective dose for a generic patient
3. Discuss how patient specific risk estimates may be performed
4. Review dose metrics and radiobiology relevant to the modality
5. Provide a detailed review of fetal dose risk from ionizing and nonionizing radiation
6. Provide a detailed review of dose calculation techniques (with examples) for planar
radiography, fluoroscopy, CT, nuclear medicine/PET
7. Provide a priori discussion points for women that may need to be imaged while pregnant, or how
to have a conversation with a women a posteriori that was imaged while pregnant.



Not Applicable / None Entered.


Not Applicable / None Entered.

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