Potential for lower absorbed dose in digital mammography: a JAFROC experiment using clinical hybrid images with simulated dose reduction

Purpose: To determine how image quality linked to tumor detection is affected by reducing the absorbed dose to 50% and 30% of the clinical levels represented by an average glandular dose (AGD) level of 1.3 mGy for a standard breast according to European guidelines. Materials and methods: 90 normal, unprocessed images were acquired from the screening department using a full-field digital mammography (FFDM) unit Mammomat Novation (Siemens). Into 40 of these, one to three simulated tumors were inserted per image at various positions. These tumors represented irregular-shaped malignant masses. Dose reduction was simulated in all 90 images by adding simulated quantum noise to represent images acquired at 50% and 30% of the original dose, resulting in 270 images, which were subsequently processed for final display. Four radiologists participated in a free-response receiver operating characteristics (FROC) study in which they searched for and marked suspicious positions of the masses as well as rated their degree of suspicion of occurrence on a one to four scale. Using the jackknife FROC (JAFROC) method, a score between 0 and 1 (where 1 represents best performance), referred to as a figure-of-merit (FOM), was calculated for each dose level. Results: The FOM was 0.73, 0.70, and 0.68 for the 100%, 50% and 30% dose levels, respectively. Using Analysis of the Variance (ANOVA) to test for statistically significant differences between any two of the three FOMs revealed that they were not statistically distinguishable (p-value of 0.26). Conclusion: For the masses used in this experiment, there was no significant change in detection by increasing quantum noise, thus indicating a potential for dose reduction.

[1]  C. J. Kotre,et al.  The effect of background structure on the detection of low contrast objects in mammography. , 1998, The British journal of radiology.

[2]  Bengt Hemdal,et al.  Comparison of screen-film, imaging plate and direct digital mammography with CD phantoms , 2003 .

[3]  Ehsan Samei,et al.  Characterization of breast masses for simulation purposes , 2004, SPIE Medical Imaging.

[4]  N. Perry,et al.  European Guidelines for Quality Assurance in Mammography Screening , 1996 .

[5]  M Ruschin,et al.  Can the average glandular dose in routine digital mammography screening be reduced? A pilot study using revised image quality criteria. , 2005, Radiation protection dosimetry.

[6]  Dev P. Chakraborty,et al.  Jackknife free-response ROC methodology , 2004, SPIE Medical Imaging.

[7]  S. Obenauer,et al.  Applications and literature review of the BI-RADS classification , 2005, European Radiology.

[8]  A. Burgess,et al.  Human observer detection experiments with mammograms and power-law noise. , 2001, Medical physics.

[9]  Anders Tingberg,et al.  Method of simulating dose reduction for digital radiographic systems. , 2005, Radiation protection dosimetry.

[10]  S Muller,et al.  Full-field digital mammography designed as a complete system. , 1999, European journal of radiology.

[11]  C. J. Kotre,et al.  Additional factors for the estimation of mean glandular breast dose using the UK mammography dosimetry protocol. , 2000, Physics in medicine and biology.

[12]  M Ruschin,et al.  Using simple mathematical functions to simulate pathological structures--input for digital mammography clinical trial. , 2005, Radiation protection dosimetry.

[13]  Angelo Taibi,et al.  Patient dose in full-field digital mammography: an Italian survey , 2004, European Radiology.

[14]  Dev P Chakraborty,et al.  Observer studies involving detection and localization: modeling, analysis, and validation. , 2004, Medical physics.

[15]  F R Verdun,et al.  Estimation of the noisy component of anatomical backgrounds. , 1999, Medical physics.

[16]  M. Ruschin,et al.  A software tool for increased efficiency in observer performance studies in radiology. , 2005, Radiation protection dosimetry.

[17]  C. Metz.  ROC Methodology in Radiologic Imaging , 1986, Investigative radiology.

[18]  L. Tabár,et al.  Potential contribution of computer-aided detection to the sensitivity of screening mammography. , 2000, Radiology.