title: Scope for energy improvement for hospital imaging services in the USA.
abstract: OBJECTIVE
  To aid radiologists by measuring the carbon footprint of CT scans by quantifying in-hospital and out-of-hospital energy use and to assess public health impacts.
  
  
  METHODS
  The study followed a standard life cycle assessment protocol to measure energy from a CT scan then expanding to all hospital electrical energy related to CT usage. In addition, all the fuel energy used to generate electricity and to manufacture the CT consumables was measured. The study was conducted at two hospitals.
  
  
  RESULTS
  The entire life cycle energy for a CT scan was 24-34 kWh of natural resource energy per scan. The actual active patient scan energy that produces the images is only about 1.6% of this total life cycle energy. This large multiplier to get total CT energy is a previously undocumented environmental response to the direct radiology order for a patient CT scan. The CT in-hospital energy related to idle periods, where the machine is on but no patients are being scanned and is 14-30-fold higher than the energy used for the CT image. The in-hospital electrical energy of a CT scan makes up only about 25% of the total energy footprint. The rest is generated outside the hospital: 54-62% for generation and transmission of the electricity, while 13-22% is for all the energy to make the consumables. Different CT scanners have some influences on the results and could help guide purchase of CT equipment.
  
  
  CONCLUSIONS
  The transparent, detailed life cycle approach allows the data from this study to be used by radiologists to examine details of both direct and of unseen energy impacts of CT scans. The public health (outside-the-hospital) impact (including the patients receiving a CT) needs to be measured and included.
authors.affiliation: M.Sc. in Engineering Systems, Industrial and Manufacturing Engineering Department, Wichita State University, KS, USA.
authors.forename: Amin
authors.initials: A
authors.lastname: Esmaeili
authors.affiliation: Professor in Industrial and Manufacturing Engineering, Industrial and Manufacturing Engineering Department, Wichita State University, KS, USA janet.twomey@wichita.edu.
authors.forename: Janet M
authors.initials: JM
authors.lastname: Twomey
authors.affiliation: Professor in Sustainable Materials and Energy Systems, Industrial and Manufacturing Engineering Department, Wichita State University, KS, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Overcash
authors.affiliation: Post-Doctoral Fellow, Industrial and Manufacturing Engineering Department, Wichita State University, KS, USA.
authors.forename: Seyed A
authors.initials: SA
authors.lastname: Soltani
authors.affiliation: Clinical Associate Professor, University of Kansas School of Medicine, Wichita, KS, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: McGuire
authors.affiliation: Clinical Associate Professor, University of Kansas School of Medicine, Wichita, KS, USA.
authors.forename: Kamran
authors.initials: K
authors.lastname: Ali
mesh_terms: D058572:Carbon Footprint; D004560:Electricity; D006801:Humans; D007615:Kansas; D011872:Radiology Department, Hospital; D015898:Tomography Scanners, X-Ray Computed / Q000706:statistics & numerical data; D014481:United States
keywords: CT scans; environmental sustainability; life cycle assessment