LA DETERMINATION OF PERSONALIZED MEAN GLANDULAR DOSEUSING ESTIMATES OF THE GLANDULAR TISSUE DISTRIBUTIONIN A CLINICAL SETTING
Palabras clave:
mean glandular dose, mammography dosimetry, glandular tissue distributionResumen
troduction: The effect due to the glandular tissue distribution is not considered in the currently used mammography dosimetry methods. The effect in mean glandular dose (MGD) is solely dependent on the particular glandular tissue distribution for a patient. Objective: Develop a methodology for personalized calculations of mean glandular dose (MGD) conversion coefficients in a clinical setting incorporating estimates of the glandular tissue distribution for each patient using information and resources commonly available in clinical practice.
Methods: 20 patients with craniocaudal (CC) and mediolateral oblique (MLO) views were studied. Distributions of glandular tissue were estimated visually by a radiologist. MGD coefficients were calculated using three independent methods: (1) Monte Carlo simulations with traditional geometry, (2) Monte Carlo simulations with heterogeneously-layered breast (HLB) geometry, and (3) individual glandular tissue distribution correction factor (kdist).
Results: Differences of up to 19% were found between the dose coefficients calculated using the traditional geometry (1) with respect to those calculated using the HLB geometry (2). These differences are due solely to the individual distributions of glandular tissue. The use of the correction factor kdist (3) has results comparable to those from Monte Carlo (2) with a 4.2% median difference. Conclusion: The use of kdist and radiologist assessment of the glandular tissue distribution provides reasonable estimates of the patient-based MGD coefficients in the absence of breast density map and Monte Carlo techniques. The use of the methods presented in this work is recommended particularly in MGD calculations for highly heterogeneous breasts.
Autor de correspondencia: Mariela A. Porras-Chaverri (porraschaver@wisc.edu)
Referencias
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