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Abstract: 150-1

150-1

DIAGNOSTIC REFERENCE LEVELS FOR MAMMOGRAPHY IN A DEVELOPING COUNTRY: A KEY STEP FOR AN AWARE IRRADIATION

Authors:
Helen’s Irais Sánchez Mendoza (IMSS - Instituto Mexicano del Seguro Social) ; Abraham Gonzalez Ruiz (ININ - INSTITUTO NACIONAL DE INVESTIGACIONES NUCLEARES) ; Keila Isaac Olive (UAEMEX - Universidad Autónoma del estado de México) ; Miriam Veronica Flores Merino (UAEMEX - Universidad Autónoma del estado de México) ; Clara Leticia Santos Cuevas (ININ - INSTITUTO NACIONAL DE INVESTIGACIONES NUCLEARES)

Abstract:

In Mexico, breast cancer is the leading cause of death for women aged 20 and over (1). Mammography remains the most effective method for detecting breast cancer in its early stages. Implementing a Quality Control Program (QCP) within a Quality Assurance Program (QAP) for mammography ensures the acquisition of accurate diagnostic information at the lowest possible mean glandular dose (MGD) of radiation (2). Nevertheless, Mexico currently lacks a national MGD registry, and its regulatory framework for mammography is outdated in terms of radiation safety. A recent study further highlighted this issue, revealing that only 10.64% of evaluated mammography facilities achieved full compliance (100%) with the QAP Mexican regulation indicators (2). These findings underscore the need for a more comprehensive characterization of radiological protection practices in Mexico and the development of diagnostic reference levels for mammography.

This observational analytic cross-sectional study conducted on 23 digital mammographs distributed throughout Mexico over the period of time of June 2023 to May 2024 reports de local Diagnostic Reference Levels in mammography for the craneocaudal (CC) and mediolateral oblique (MLO) projections. A total of 4476 acquisitions were ghatered for the study. Mammographic cases for screening women aged 35 to 85 years were included, while cases of breast implants and breast thickness outside the range 20-100 mm were excluded. Mainly the patients were categorized into two groups based on age: adults (18 years > age <60 years), and elderly (age ≥60 years) to analyze MGD behavior regarding age. Besides, patients were grouped considering compressed breast thickness (CBT) in four intervals: CBT < 20, 20 ≤ CBT < 40, 40 ≤ CBT < 60, 60 ≤ CBT ≤ 80, and CBT > 80 mm. Finally, patients were grouped considering mammography projections (CC and MLO).

Patient data related required for dose calculations were extracted from the Digital Imaging and Communication in Medicine (DICOM) headers and exported to a CSV format file. The tube output, HVL (for all kVps) and anode/filter combinations available were acquired for each mammography facility for  MGD calculations proposed. Mean, median and 75 percentiles were obtained for the MGD distribution of each mammography projection for all compressed breast thickness (CBT) ranges (3). The local DRLs for mammography were found to be between 2.31 mGy and 3.30 for CC and MLO projections respectively. The local DRLs from this study were relatively high in comparison to an international framework but lower that the standrd reference levels reported by the International Atomic Energy Agency (IAEA) at 3 mGy/view (4). The results of the survey allow us to propose to the ministry of health the first local DRLs in mammography in Mexico. 

 

 

Keywords:
 Mammography, Mean Glandular Dose, Dignostic reference levels