Medical Physics Research Today is a free monthly online journal that collates and summarizes the latest research about Medical Physics, including details on medicine, radiotherapy, biomechanics, medical imaging.

Time-dependent observer errors in pulmonary nodule detection.

Manning D, Barker-Mill SC, Donovan T, Crawford T

School of Medical Imaging Sciences, St Martin's College, Lancaster LA1 3JD, UK.

The work was carried out to investigate differences in visual search characteristics between groups of observers with different levels of experience in the task of pulmonary nodule detection in chest radiology and we report here on these differences in respect of time related decisions. Volunteer observers were divided into three groups depending on their level of expertise. There were eight radiologists, eight radiographers and eight novices. Their task was to detect pulmonary nodules in a test bank of 120 digitized posteroanterior (PA) chest radiographs. Five of the eight radiographers were tested twice: once before and once after a 6-month training programme in interpretation of the adult chest radiograph. During each test session the observers' eye movements were tracked. Data on the observers' decisions through Alternate Free Response Operating Characteristic (AFROC) methodology were correlated to their eye-movement and fixation patterns. True negative decisions from all observers were associated with shorter fixation times than false negative decisions. No correct negative decisions were made after fixations exceeding 3 s.

Published 4 April 2006 in Br J Radiol, 79(940): 342-6.
Full-text of this article is available online (may require subscription).

© 2005-2008 Medical Physics Research Today. All Rights Reserved.