title: Deep-inspiration breath-hold PET/CT of the thorax.
abstract: The goal of this study was to describe our initial experience with the deep-inspiration breath-hold (DIBH) technique in combined PET/CT of the thorax. This article presents particular emphasis on the technical aspects required for clinical implementation.
  
  
  METHODS
  In the DIBH technique, the patient is verbally coached and brought to a reproducible deep inspiration breath-hold level. The first "Hold" period, which refers to the CT session, is considered as the reference. This is followed by 9- to 20-s independent breath-hold PET acquisitions. The goal is to correct for respiratory motion artifacts and, consequently, improve the tumor quantitation and localization on the PET/CT images and inflate the lungs for possible improvement in the detection of subcentimeter pulmonary nodules. A physicist monitors and records patient breathing during PET/CT acquisition using a motion tracker. Patient breathing traces obtained during acquisition are examined on the fly to assess the reproducibility of the technique.
  
  
  RESULTS
  Data from 8 patients, encompassing 10 lesions, were analyzed. Visual inspection of fused PET/CT images showed improved spatial matching between the 2 modalities, reduced motion artifacts especially in the diaphragm, and increased the measured standardized uptake value (SUV) attributed to reduced motion blurring, as compared with the standard clinical PET/CT images.
  
  
  CONCLUSIONS
  The practice of DIBH PET/CT is feasible in a clinical setting. With this technique, consistent lung inflation levels are achieved during PET/CT sessions, as judged by both motion tracker and verification of spatial matching between PET and CT images. Breathing-induced motion artifacts are significantly reduced using DIBH compared with free breathing, enabling better target localization and quantitation. The DIBH technique showed an increase in the median SUV by 32.46%, with a range from 4% to 83%, compared with SUVs measured on the clinical images. The median percentage reduction in the PET-to-CT lesions' centroids was 26.6% (range, 3%-50%).
authors.affiliation: Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. nehmehs@mskcc.org
authors.forename: Sadek A
authors.initials: SA
authors.lastname: Nehmeh
authors.forename: Yusuf E
authors.initials: YE
authors.lastname: Erdi
authors.forename: Gustavo S P
authors.initials: GS
authors.lastname: Meirelles
authors.forename: Olivia
authors.initials: O
authors.lastname: Squire
authors.forename: Steven M
authors.initials: SM
authors.lastname: Larson
authors.forename: John L
authors.initials: JL
authors.lastname: Humm
authors.forename: Heiko
authors.initials: H
authors.lastname: Schöder
mesh_terms: D000328:Adult; D000368:Aged; D016477:Artifacts; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted; D012119:Respiration; D013909:Thorax / Q000000981:diagnostic imaging* / Q000473:pathology; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*