Evaluation and analysis of entrance surface air kerma of the thyroid gland during breast cancer screening mammography

Objective:To evaluate and analyze entrance surface air kerma(ESAK)of the thyroid during mammographies performed in a breast cancer screening program.Methods:The ESAK was measured for the left and right lobes of the thyroid gland for 120 female subjects undergoing routine mammographic screenings.All measurements were single-handedly performed on the Hitachi Hologic LORAD M-IVTM screen-film mammography system.Radiation dose measurements were made using optically stimulated luminescent dosimeters(OSLD)nanoDot™taped appropriately to the skin overlying the right and left lobes of the thyroid gland.The standard technique of two craniocaudal(CC)views and two mediolateral oblique(MLO)views with appropriate compression was used during the screening.Results:The average ESAK was(287102)μGy.The value of radiation dose to the thyroid was estimated as 71.17μGy.Compresssed breast thichness(CBT)was found as key parameter influencing radiation dose to the thyroid gland during mammography.ESAK changed approximately two folds for the CBT range of 2–5 cm.Radiation dose to the thyroid gland was increased with higher body mass index(BMI).Conculsions:A proper compression of the breast is crucial for the mammographic examination.In addition to applied exposure factors for examination,breast compression is the principal and influencing factor that affects various other parameters used during mammographic examinations,which in turn impact radiation dose to the thyroid gland.

Implementation of safety and security standards for high dose rate brachytherapy sealed radioactive source used in a medical radiation facility

Objective:To provide guidance on basic concepts and elements for radiation safety and security measures for a HDR brachytherapy sealed radioactive source in a medical radiation facility.Methods:Brachytherapy sources are Category 2(High risk-very dangerous)radioactive source and Security Level B applied to cover the range of security measures needed for the associated risk with remote afterloading HDR brachytherapy sources.These security measures were applied based on a risk informed graded approach.A series of in-build and operational safety measures were implemented for equipment and radiation installation.Results:The medical radiation facility equipped with adequate radiation protection,detection and monitoring equipment such as survey meter,digital contamination monitor,gamma zone monitor,digital radiation monitor,personnel dosimeter,pocket dosimeter,long handled forceps,shielding material and emergency source storage container etc.to deal with radiological incidences.The contingency plan with security objectives for incidents and procedures for action was prepared in order to implement response function to fulfill the goal of adequate security of radioactive source.The emergency response plan documented against emergency scenarios during transport,loss of radioactive source,theft,sabotage,natural calamities/disasters such as fire,flood and earthquake.Conculsions:The paper provides various radiation safety and security aspects for the HDR brachytherapy.The HDR brachytherapy radioactive sources are Type A packages.Transport of radioactive material is the responsibility of consignors,consignee and carriers under the legislation,supervision and control of regulatory authority.