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.

Optimization of the Eclipse TPS beam configuration parameters for small field dosimetry using Monte Carlo simulations and experimental measurements.

PURPOSE: To evaluate the impact of tuning the beam configurations parameters on the Analytical Anisotropic Algorithm (AAA) and the Acuros XB (AXB) algorithm for small fields using Monte Carlo simulations and measurements. METHODS: The TrueBeam STx with the high-definition 120 multi-leaf collimator (HD120-MLC) was modeled with Geant4 application for emission tomography (GATE) Monte Carlo platform and validated against measurements. The impact of varying the effective spot size (ESS) and dosimetric leaf gap (DLG) on AAA and AXB calculations was carried out for small MLC-fields ranging from 0.5×0.5 cm2 to 3 × 3 cm2. Beam penumbras, field sizes and output factors calculated by AAA and AXB were compared to GATE calculations and measurements. RESULTS: The beam penumbra comparisons showed that the best ESS value for AXB was about 1.0 mm in the crossplane direction and 0.5 mm in the inplane direction. By optimizing the ESS values, AXB could provide output factor results almost within 2% of GATE calculations and measurements for fields down to 0.5×0.5 cm2. For AAA, significant output factor differences were observed for all ESS values and tuning the DLG in addition to the ESS optimization resulted in an absorbed dose difference of less than 2.5% for MLC-fields down to 1 × 1 cm2. CONCLUSION: By optimizing the ESS values, AXB can achieve accurate output factors in the case of small MLC-fields without the need of DLG tuning. Nevertheless, compromises between the output factor, DLG and ESS values were found necessary for AAA calculations. A MLC model improvement would allow to avoid the complexity related to tuning the configuration parameters.

An Explainable MRI-Radiomic Quantum Neural Network to Differentiate Between Large Brain Metastases and High-Grade Glioma Using Quantum Annealing for Feature Selection.

Solitary large brain metastases (LBM) and high-grade gliomas (HGG) are sometimes hard to differentiate on MRI. The management differs significantly between these two entities, and non-invasive methods that help differentiate between them are eagerly needed to avoid potentially morbid biopsies and surgical procedures. We explore herein the performance and interpretability of an MRI-radiomics variational quantum neural network (QNN) using a quantum-annealing mutual-information (MI) feature selection approach. We retrospectively included 423 patients with HGG and LBM (> 2 cm) who had a contrast-enhanced T1-weighted (CE-T1) MRI between 2012 and 2019. After exclusion, 72 HGG and 129 LBM were kept. Tumors were manually segmented, and a 5-mm peri-tumoral ring was created. MRI images were pre-processed, and 1813 radiomic features were extracted. A set of best features based on MI was selected. MI and conditional-MI were embedded into a quadratic unconstrained binary optimization (QUBO) formulation that was mapped to an Ising-model and submitted to D'Wave's quantum annealer to solve for the best combination of 10 features. The 10 selected features were embedded into a 2-qubits QNN using PennyLane library. The model was evaluated for balanced-accuracy (bACC) and area under the receiver operating characteristic curve (ROC-AUC) on the test set. The model performance was benchmarked against two classical models: dense neural networks (DNN) and extreme gradient boosting (XGB). Shapley values were calculated to interpret sample-wise predictions on the test set. The best 10-feature combination included 6 tumor and 4 ring features. For QNN, DNN, and XGB, respectively, training ROC-AUC was 0.86, 0.95, and 0.94; test ROC-AUC was 0.76, 0.75, and 0.79; and test bACC was 0.74, 0.73, and 0.72. The two most influential features were tumor Laplacian-of-Gaussian-GLRLM-Entropy and sphericity. We developed an accurate interpretable QNN model with quantum-informed feature selection to differentiate between LBM and HGG on CE-T1 brain MRI. The model performance is comparable to state-of-the-art classical models.

Towards the standardization of the absorbed dose report mode in high energy photon beams.

The benefits of using an algorithm that reports absorbed dose-to-medium have been jeopardized by the clinical experience and the experimental protocols that have mainly relied on absorbed dose-to-water. The aim of the present work was to investigate the physical aspects that govern the dosimetry in heterogeneous media using Monte Carlo method and to introduce a formalism for the experimental validation of absorbed dose-to-medium reporting algorithms. Particle fluence spectra computed within the sensitive volume of two simulated detectors (T31016 Pinpoint 3D ionization chamber and EBT3 radiochromic film) placed in different media (water, RW3, lung and bone) were compared to those in the undisturbed media for 6 MV photon beams. A heterogeneity correction factor that takes into account the difference between the detector perturbation in medium and under reference conditions as well as the stopping-power ratios was then derived for all media using cema calculations. Furthermore, the different conversion approaches and Eclipse treatment planning system algorithms were compared against the Monte Carlo absorbed dose reports. The detectors electron fluence perturbation in RW3 and lung media were close to that in water (≤1.5%). However, the perturbation was greater in bone (∼4%) and impacted the spectral shape. It was emphasized that detectors readings should be corrected by the heterogeneity correction factor that ranged from 0.932 in bone to 0.985 in lung. Significant discrepancies were observed between all the absorbed dose reports and conversions, especially in bone (exceeding 10%) and to a lesser extent in RW3. Given the ongoing advances in dose calculation algorithms, it is essential to standardize the absorbed dose report mode with absorbed dose-to-medium as a favoured choice. It was concluded that a retrospective conversion should be avoided and switching from absorbed dose-to-water to absorbed dose-to-medium reporting algorithm should be carried out by a direct comparison of both algorithms.

Comparative study between Fenton and intergrowth 21 charts in a sample of Lebanese premature babies.

BACKGROUND: Different charts are used to assess premature growth. The Fenton chart, based on prenatal growth, has been used in the neonates' intensive care unit (NICU) of the Notre Dame des Secours University Hospital to assess premature newborns' development. Intergrowth21 is a new multidisciplinary, multiethnic growth chart better adapted to premature growth. Our objective was to compare both charts Fenton and Intergrowth21 in order to implement Intergrowth in our unit. METHODS: We analyzed 318 files of premature babies born who were admitted to the NICU from 2010 till 2017. Anthropometric data (weight, height and head circumference) converted to percentiles was filled on both charts from birth till 1 month of age. RESULTS: The results of the linear regression, taking the weight at birth as the dependent variable, showed that the Fenton scale (R2 = 0.391) would predict the weight at birth better than the Intergrowth 21 scale (R2 = 0.257). The same applies for height and cranial perimeter at birth when taken as dependent variables. When considering the weight and height at 2 weeks, the results showed that the Intergrowth 21 scale would predict those variables better than the Fenton scale, with higher R2 values higher in favor of the Intergrowth 21 scale for both weight (0.384 vs 0.311) and height (0.650 vs 0.585). At 4 weeks, the results showed that the Fenton scale would predict weight (R2 = 0.655 vs 0.631) and height (R2 = 0.710 vs 0.643) better than the Intergrowth 21 scale. The results obtained were adjusted over the newborns' sociodemographic and clinical factors. CONCLUSION: The results of our study are controversial where the Fenton growth charts are superior to Intergrowth 21 before 2 weeks of age and at 4 weeks, whereas Intergrowth 21 charts showed higher percentiles for weight and height than Fenton charts at 2 two weeks of age. Further studies following a different design, such as a clinical trial or a prospective study, taking multiple ethnicities into account and conducted in multiple centers should be considered to enroll a more representative sample of Lebanese children and be able to extrapolate our results to the national level.

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.

Joint line restoration during revision total knee arthroplasty: an accurate and reliable method.

During revision total knee arthroplasty, the joint line is frequently malpositioned, due to the disappearance of the anatomical landmarks following previous interventions. This leads to decreased clinical outcome and increased risk of re-intervention. Many methods have been proposed to restore the joint line, but none of them has shown itself to be reliable. We describe an accurate and precise method to localize the exact position of the joint line which guarantees a better clinical knee score. The adductor tubercle (AT) is recognized to be the most reliable landmark used to localize the knee joint line (JL). The distance from the AT to the JL on antero-posterior radiographs (ATJL) and the femoral diameter (FD) on true lateral views were measured on 200 randomly selected normal knees. These measurements were tested for intra- and inter-observer differences. Then, the relationship between these two measurements was studied. A significant correlation and linear regression between FD and ATJL was found (p < 0.001), making the adductor tubercle a valid landmark to accurately position the prosthetic joint within 4 mm from the normal position. No significant difference was noted in the intra and inter-observer measurements (F test not significant). Sex was found to be an intervening variable (p Ë‚ 0.001). The correlation and regression between ATJL and FD had to be adjusted accordingly. Once the ATJL was determined preoperatively, the JL level is found during surgery by using a caliper that is held on the easily palpable AT. Knowing the femoral diameter, we can easily locate the joint line level surgically, using the adductor tubercle as a landmark. This method leads to better clinical outcomes and a reduced risk of re-intervention following revision total knee arthroplasty.

A single formula to describe radiation-induced protein relocalization: towards a mathematical definition of individual radiosensitivity.

Immunofluorescence with antibodies against DNA damage repair and signaling protein is revolutionarising the estimation of the genotoxic risk. Indeed, a number of stress response proteins relocalize in nucleus as identifiable foci whose number, pattern and appearance/disappearance rate depend on several parameters such as the stress nature, dose, time and individual factor. Few authors proposed biomathematical tools to describe them in a unified formula that would be relevant for all the relocalizable proteins. Based on our two previous reports in this Journal (Foray et al., 2005; Gastaldo et al., 2008), we considered that foci response to stress is composed of a recognition and a repair phase, both described by an inverse power function provided from a Euler's Gamma distribution. The resulting unified formula called "Bodgi's function" is able to describe appearance/disappearance kinetics of nuclear foci after any condition of genotoxic stress. By applying the Bodgi's formula to DNA damage repair data from 45 patients treated with radiotherapy, we deduced a classification of human radiosensitivity based on objective molecular criteria, notably like the number of unrepaired DNA double-strand breaks and the radiation-induced nucleo-shuttling of the ATM kinase.

Foreign body granulomatosis in a patient with a factitious disorder.

A 42-year-old woman was hospitalized with fever and hypoxemia. The workup for fever was unrevealing. A computed tomographic scan of the chest showed centrilobular, small, nodular opacities throughout both the lung fields. A flexible bronchoscopy with transbronchial biopsy was performed. Pathology specimens consisted of intravascular foreign material with birefringent properties suggestive of microcrystalline cellulose. It was later determined that the patient was self-injecting herself with crushed pill fragments through a tunneled central venous catheter. The central venous catheter was removed and fever resolved.

Practical use of Gafchromic(®) EBT films in electron beams for in-phantom dose distribution measurements and monitor units verification.

PURPOSE: The possibility of using the Gafchromic(®) EBT films parallel to incident electron beams was assessed in order to facilitate quality assurance tests for electron dose calculation algorithms. MATERIALS AND METHODS: Calibration curves were made for electron energies of 6, 9 and 12MeV. A set-up was suggested for EBT film irradiation parallel to the beam, and the dose measurements were compared to Ionization Chamber (IC) measurements in standard and small electrons beams. A more complex Quality Assurance (QA) set-up was performed with the cylindrical CARPET(®) phantom in order to test our Treatment Planning System (TPS) (Eclipse, Varian Medical Systems, Palo Alto, California) for the clinical situation of a chest wall electron beam therapy. Two dimensional dose distribution and gamma index results were compared to the calculated distribution given by the TPS. RESULTS: The reproducibility was found to be better than 1.5%. We found that applying strong pressure and aligning carefully the film edge with the phantom surface, as recommended for radiographic films, did not completely eliminate the air gap effect. Adding an ultrasound transmission gel and 2 complementary EBT films on the surface gave satisfactory results. The absolute dose for the reference 10×10cm(2) field was always within 1% of IC measurements and for smaller elongated fields (5×10, 4×10 and 3×10cm(2)) the mean difference was -1.4% for the three energies. The mean difference with the IC measurements in R(100), R(90) and R(50) was 0.9mm for all fields and for the three energies. The mean difference in the width of the 90% and the 50% isodoses at R(100) was 0.6mm. With the CARPET(®) phantom set-up very good agreement was found in the 2D dose distribution; 99% of the points satisfied the γ<1 criteria (3%-3mm). CONCLUSION: EBT films parallel to the beam axis could be used for absolute measurements of 2D dose distribution if ultrasound gel and overlying perpendicular films are added on the phantom surface.

Outcome and prognostic factors in the conservative treatment of breast cancer.

BACKGROUND: The aim of this retrospective study is to evaluate the results and identify prognostic factors in early breast cancer. MATERIALS AND METHODS: One hundred breast cancers, 79 stage I and 21 stage II, had a conservative treatment between September 1993 and February 1996. Median age was 57 years; median tumor size 15 mm. Pathology was infiltrating ductal carcinoma in 88%. All patients underwent a conservative surgery followed by external radiotherapy. Twenty-eight patients received adjuvant chemotherapy and 64 patients received hormonal therapy. The median follow-up was 100 months. RESULTS: The 10 years overall survival rate was 85% and the metastasis free survival rate was 88.5%. The 10 years local control rate was 85.7%. Women less than 45 years old had a worse prognosis. CONCLUSION: These high rates of survival and local control confirm that breast conservation therapy yields favorable results, and that age is a major risk factor in women with early breast cancer.

[A five-year experience in conformational radiotherapy in the treatment of prostate cancer. Evaluation of acute toxicity in 131 patients]. / Radiothérapie conformationnelle dans le traitement du cancer de la prostate. Evaluation de la toxicité aiguë chez 131 patients.

PURPOSE: To evaluate the urinary and rectal toxicity secondary to 3D conformal radiotherapy for prostate cancer. MATERIAL AND METHODS: Between 1998 and 2003, 131 men with prostate cancer underwent 3D conformal radiotherapy with or without androgen deprivation. The different stages were: 2 T1b ; 40 T1c; 19 T2a; 16 T2b; 18 T2c; 33 T3a; 1 T3b and 2 T3c with Gleason score: 4-6 = 47%, 7 = 36% and 8-9 in 17% of the cases. The median patient age was 66 (48-87). Pretreatment PSA level was respectively < 10 ng/ml (41%). 10-20 ng/ml (30%) and > 20 ng/ml (29%). Of the 131 patients, 98 received androgen ablation therapy before radiation. The total radiation dose varied between 66 and 74 Gy, delivered with 18MV photons of the linear accelerator, the median follow up was 33 months (5-67). RESULTS: According to the RTOG grading (gr) for acute toxicity, we noticed 3gr 3 genitourinary (GU) toxicity and no gr3 gastro intestinal (GI) toxicity. There were 36 gr 1 and 12 gr 2 GI toxicity, 41 gr 1 and 22 gr 2 GU toxicity. The mean prostate volume was 41 cc for patients who received androgen ablation and 56 cc for the others (p < 0.002). The percentage of volume receiving more than 50 Gy (V50) was calculated, the median V50 was 32% (5-67) for the rectum and 35% (5-79) for the bladder CONCLUSION: The toxicity profile in this study is in the same range than those of the literature and of our previous study concerning our first 50 patients with prostate cancer treated with 3D conformal radiotherapy.