Craig A. Morioka PhD, Abstract Co-Author: Nothing to Disclose

Michael F. McNitt-Gray PhD, Presenter: Institutional research agreement, Siemens AG Research Grant, Siemens AG Instructor, Medical Technology Management Institute

Gholam Reza Berenji MD, Abstract Co-Author: Investigator, Siemens AG Investigator, Lantheus Medical Imaging, Inc Investigator, Koninklijke Philips Electronics NV

Kyle Brubaker, Abstract Co-Author: Nothing to Disclose

Adam Christopher Turner PhD, Abstract Co-Author: Nothing to Disclose

Suzie M. El-Saden MD, Abstract Co-Author: Nothing to Disclose

There were an estimated 72 million CT scans performed in the United States in 2007, approximately 20% received moderate exposure of 3-20 mSv, and 2% (1.4 million) received a high dose of 20-50mSv. The purpose of our research is to develop a DICOM Structured Report to capture Veteran's organ dose from an abdominal CT scan. This record of the patient’s organ dose can be stored within our commercial PACS system so that long term cumulative dose (and potentially risk) maybe calculated.  

Currently, national and international groups (American College of Radiology, FDA, International Atomic Energy Agency, NIH) are advocating for radiation dose to be recorded and tracked for patients. However, the only information currently recorded by CT scanners is the dose to a standardized phantom, known as the CT Dose Index (CTDI), which is not patient dose. The primary focus of this research is to provide in depth information about patient’s radiation doses from CT exams, with the initial investigation involving estimating organ dose that results from abdominal CT exams. Current dose measurement methods (i.e. CTDIvol Computed Tomography Dose Index) do not provide direct information about organ dose. The CTDIvol is a standardized measure of radiation output of a CT system.  We recently reported on a method to determine CTDIvol normalized organ doses using a set of organ specific exponential regression equations of the form A*e^(B*p) (A,B fitting parameters, p=patient perimeter). These were used together with measured CTDIvol to calculate organ dose estimates from abdominal CT scans for 176 veteran patients

Figure 1 depicts our results.  The graph shows the mean organ dose/CTDIBvol as a function of the patient perimeter size for 7 organs (liver, stomach, adrenals, kidneys, gall bladder, spleen, and pancreas) within the abdomen.  The 176 patients were acquired from 2 different CT scanners.

We have implemented DICOM Supplement 127 for capturing the organ dose (liver stomach, adrenals, kidneys, and pancreas) and dose index information for patients undergoing abdominal CT scans. The DICOM SR object/schema allows the clinician to view the CT dose for a patient through a web server on the local radiology review workstation.

Converting CTDIvol to organ dose renders clinical relevent information concerning the cumulative dose that a patient receives during a CT image study.

Morioka, C, McNitt-Gray, M, Berenji, G, Brubaker, K, Turner, A, El-Saden, S, Tracking Veteran's Organ Dose through a DICOM Structured Report.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12023375.html