Clinical image quality assessment and mean glandular dose for full field digital mammography.

This study aims to assess the image quality (IQ) of 12 mammographic units and to identify units with potential optimisation needs. Data for 350 mammography examinations meeting inclusion criteria were collected retrospectively from April 2021 to April 2022. They were categorised based on the medical reports into 10 normal cases, 10 cases displaying calcifications and 10 cases presenting lesions. Two radiologists assessed the IQ of 1400 mammograms, evaluating system performance per Boitaet al's study and positioning performance following European guidelines. To measure agreement between the two radiologists, the Cohen's Kappa coefficient (κ) was computed, quantifying the excess of agreement beyond chance. The visual grading analysis score (VGAS) was computed to compare system and positioning performance assessments across different categories and facilities. Median average glandular dose (AGD) values for cranio caudal and medio lateral oblique views were calculated for each category and facility and compared to the national diagnostic reference levels. The health facilities were categorised by considering both IQ VGAS and AGD levels. Inter-rater agreement between radiologists ranged from poor (κ< 0.20) to moderate (0.41 <κ< 0.60), likely influenced by inherent biases and distinct IQ expectations. 50% of the facilities were classified as needing corrective actions for their system performance as they had IQ or high AGD that could increase recall rate and radiation risk and 50% of the health facilities exhibited insufficient positioning performance that could mask tumour masses and microcalcifications. The study's findings emphasise the importance of implementing quality assurance programs to ensure optimal IQ for accurate diagnoses while adhering to radiation exposure guidelines. Additionally, comprehensive training for technologists is essential to address positioning challenges. These initiatives collectively aim to enhance the overall quality of breast imaging services, contributing to improved patient care.

On the risk of secondary cancer from thymoma radiotherapy.

Objective.This study aims at quantifying the lifetime attributable risk of secondary fatal cancer (LARFAC) to patients receiving adjuvant radiotherapy treatment for thymoma, a neoplasm where cure rates and life expectancy are relatively high, patient age at presentation relatively low and indications for radiotherapy controversial depending on the disease stage.Approach.An anthropomorphic phantom was scanned, organs were contoured and a standard 6 MV 3DCRT treatment plan was produced for thymoma treatment. The phantom was loaded with thermoluminescent dosimeters (TLDs) and treated by linear accelerator per plan. The TLDs were subsequently read for out-of-field dose distribution while in-field dose distribution was obtained from the planning system. Sex and age-specific lifetime radiogenic cancer risk was calculated as the sum of in-field risk and out-of-field risk. The latter risk was estimated using hybrid ICRP 2007 103-BEIR VII tables of organ-specific risks based on the linear-no threshold (LNT) model and applicable at low doses, while the former using mathematical risk models applicable at high doses.Main results.The LARFAC associated with a prescribed dose of 50 Gy to target volume in 25 fractions was in the approximate range of 1%-3%. The risk was higher for young and female patients. The largest contributing organ to this risk were the lungs by far. Using the LNT model inappropriately to calculate risk at therapeutic doses (in-field) would overestimate the risk up to tenfold.Significance.The LARFAC to patient from thymoma radiotherapy was quantified taking into consideration the inapplicability of the LNT model at therapeutic doses. The risk is not negligible; the information may be relevant to patients and clinicians.

Percutaneous closure of ventricular septal defects in children: key parameters affecting patient radiation exposure.

BACKGROUND: Ventricular septal defect (VSD) transcatheter closure is gaining worldwide popularity despite its complexity. Reports on key factors affecting radiation exposure in children are scarce. AIMS: This clinical study is the first to comprehensively analyze the impact of all relevant parameters on children's radiation exposure during VSD interventional closures. METHODS: Between March 2016 and August 2019, all pediatric VSD cases percutaneously treated at a reference center for interventional congenital cardiology and equipped with a single-plane Innova 2100 X-ray unit were retrospectively reviewed. Multiple linear regression was performed to investigate the impact of clinical, technical, and procedural parameters on patients' radiation exposure assessed using total air kerma area product (PKA,T). RESULTS: A total of 85 patients were included in this study and 82.4% had perimembranous defects. Device implantation was successful in 96.5% of cases. The procedure lasted for a median of 60 min with a median PKA,T of 19.6 Gy.cm2 (range, 1.1 to 244.8 Gy.cm2). Patients' weight (B = 1.679, P = 0.01), number of operators (B = 1.561, P = 0.02), device positioning complexity (B = 2.381, P = 0.002), and procedural incidents (B = 2.096, P = 0.008) significantly increased PKA,T. Patients' age (B = 1.053, P = 0.784), device design (B = -1.216, P = 0.780) and approach of delivery (B = -1.119, P = 0.511) did not significantly affect PKA,T. CONCLUSIONS: Radiation exposure in children undergoing VSD percutaneous closure was highly variable. A higher patient's weight, numbers of operators, complexity in device positioning, and procedural incidents, were identified as key factors increasing patient dose for this kind of intervention.

Investigating the parameters that affect the radiation exposure and establishing typical values based on procedure complexity for cerebral angiography and brain aneurysm embolization.

PURPOSE: The purpose of this study is to investigate the parameters that affect the radiation exposure and to establish typical values (TV) based on procedure complexity for cerebral angiography (CA) and brain aneurysm embolization (BAE). METHODS: Clinical parameters and exposure data were retrospectively reviewed for 348 examinations performed between March 2016 and December 2019 at a single specialized neuroradiology center. TV were derived as the median value of the distribution of exposure parameters such as total air kerma area product (PKA,T), air kerma at the patient entrance reference point, fluoroscopy time, and number of frames. A statistical analysis was conducted to investigate the exposure variability with patient's gender, number of treated vessels during CA and patient gender, aneurysm location and dimension, and treatment strategies during BAE. RESULTS: Patient gender was associated with a significant increase in the exposure level for both CA and BAE. For CA, TV were in term of PKA,T of 52 Gycm2 for male vs. 28 Gycm2 for female patients. For BAE, these were 113 Gycm2 for male vs. 75 Gycm2 for female patients. Exposure levels increased significantly with the number of treated vessels in CA. TV were 20 Gycm2 for one vessel vs. 77 Gycm2 for 5-6 vessels CA. For BAE, aneurysm location was also a key factor that affects the patient exposure. TV were 55 Gycm2 for aneurysms grouped in location 1 vs. 105 Gycm2 for those grouped in location 2. CONCLUSION: Male gender, number of treated vessels, and aneurysm location are key parameters affecting patient exposure during CA and BAE procedures.

Diagnostic Reference Levels, Deterministic and Stochastic Risks in Pediatric Interventional Cardiology Procedures.

To establish diagnostic reference levels (DRLs) and investigate deterministic and stochastic risks in pediatric interventional cardiology (IC) procedures. Exposure parameters were retrospectively reviewed for 373 patients treated between May 2016 and November 2018 at a single specialized hospital. Weight specific DRLs were derived for pediatric IC procedures. Additionally, peak skin dose (Dskin,max) was measured using thermoluminescent dosimeters for a sample of 7 diagnostic and 43 therapeutic procedures. Finally, using PCXMC software, organ doses were computed and the risk of exposure-induced cancer death (REID) was estimated using the risk models of the Biological Effects of Ionizing Radiation VII committee. DRLs for ventricular septal defect (VSD) occlusions, lacking in the literature, in terms of air kerma at patient entrance reference point (388 and 629 mGy) and total air kerma-area product (28 and 61 Gycm) were proposed for patients weight-groups 5 - < 15 kg and 15 - < 30 kg, respectively. The mean (range) Dskin,max was 15 (1-30) mGy and 94 (1-491) mGy for diagnostic and therapeutic procedures, respectively. Meanwhile, VSD occlusion involved the highest organ doses where the lungs, liver, stomach, and breasts mean doses were 57, 37, 6, and 10 mGy, respectively, and the associated REID were 0.5% and 0.3% in female and male patients, respectively. DRLs were proposed for pediatric IC procedures; these will help optimize patient exposure. Dskin,max values were lower than the 2 Gy threshold for skin injuries. Pediatric organ doses and the REID were the highest during VSD occlusion and may be critical for repetitive procedures.

RESULTS OF THE JOINT IAEA/ARPANSA INTERCOMPARISON EXERCISE ON WHOLE BODY DOSEMETERS FOR PHOTONS IN ASIA AND THE PACIFIC REGION.

An intercomparison exercise (IC) on whole body dosemeters to determine the quantity personal dose equivalent Hp (10) in photon radiation fields was jointly organised and conducted by the International Atomic Energy Agency (IAEA) and the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) for individual monitoring services (IMS) in Asia and the Pacific region. This was arranged to help the IMS in the region to achieve a more accurate dosimetry service and to improve their performance. Twenty-four IMS participated in this IC. Four sets of dosemeters were irradiated using X-ray and gamma radiation qualities at 0° and 20° angle of incidence, respectively. All the IMS provided results that were within the acceptable limits defined by the IAEA. However, only a minority of participants reported confidence intervals that included the reference dose, for each exposure scenario. For few systems, the overall performance could be significantly improved by reviewing calibration procedures.