Regional mammography dosimetry in South India: establishing modality and thickness-specific diagnostic reference levels
摘要
The mean glandular dose (MGD) is the key indicator for assessing radiation risk in mammography. International bodies such as the ICRP and IAEA recommend diagnostic reference levels (DRLs) to support optimization, yet India lacks national benchmarks. This study reports the first multicenter dosimetric survey in Tamil Nadu to derive modality- and thickness-specific DRLs.
MethodsFrom 2023 to 2025, 100 mammography units (70 CR, 20 DR, 10 DBT) across public and private facilities were evaluated. Entrance surface air kerma (ESAK), half-value layer (HVL), and compression force were measured on 30–90 mm PMMA phantoms using a calibrated solidstate detector and a parallel-plate ionization chamber. MGD was calculated with the Dance model, and 75th percentile values were adopted as DRLs following ICRP 135. Inter-detector agreement was assessed by percentage difference.
ResultsMGD increased with phantom thickness. Ion chamber-based DRLs ranged from 0.8 to 4.0 mGy for CR, 0.7–3.9 mGy for DR, and 1.3–4.5 mGy for DBT. DR demonstrated superior dose efficiency compared with CR, while DBT produced higher values due to tomographic acquisitions. Agreement between detectors was excellent (≤ 3%), validating solid-state use for large-scale surveys. Tamil Nadu DRLs were comparable to or lower than UK, Irish, and Australian values and remained well below the U.S. MQSA regulatory threshold.
ConclusionThis survey establishes the first regional ion-chamber–based DRLs for mammography in India. The findings align with international standards, provide a framework for clinical dose optimization, and form the basis for national DRL development.