Modeling of a tissue expander with a radiofrequency identification port in postmastectomy radiation therapy planning.

The purpose of this study was to evaluate the dose attenuation of Motiva Flora® (Flora, Establishment Labs, Alajuela, Costa Rica) tissue expander with a radiofrequency identification port locator and to develop a model for accurate postmastectomy radiation therapy planning. Dose attenuation was measured using an EBT3 film (Ashland, Bridgewater, NJ), and the optimal material and density assignment for the radiofrequency identification coil for dose calculation were investigated using the AcurosXB algorithm on the Eclipse (Varian Medical Systems, Palo Alto, CA) treatment planning system. Additionally, we performed in vivo dosimetry analysis using irradiation tangential to the Flora tissue expander to validate the modeling accuracy. Dose attenuations downstream of the Flora radiofrequency identification coil was 1.29% for a 6 MV X-ray and 0.99% for a 10 MV X-ray when the coil was placed perpendicular to the beam. The most suitable assignments for the material and density of the radiofrequency identification coil were aluminum and 2.27 g/cm3, respectively, even though the coil was actually made of copper. Gamma analysis of in vivo dosimetry with criteria of 3% and 2 mm did not fail in the coil region. Therefore, we conclude that the model is reasonable for clinical use.

Dose-Based Radiomic Analysis (Dosiomics) for Intensity Modulated Radiation Therapy in Patients With Prostate Cancer: Correlation Between Planned Dose Distribution and Biochemical Failure.

PURPOSE: Although radiation therapy is one of the most significant treatment modalities for localized prostate cancer, the prognostic factors for biochemical recurrence (BCR) regarding the treatment plan are unclear. We aimed to develop a novel dosiomics-based prediction model for BCR in patients with prostate cancer and clarify the correlations between the dosimetric factors and BCR. METHODS AND MATERIALS: This study included 489 patients with localized prostate cancer (BCR: 96; no-BCR: 393) who received intensity modulated radiation therapy. A total of 2475 dosiomic features were extracted from the dose distributions on the prostate, clinical target volume (CTV), and planning target volume. A prediction model for BCR was trained on a training cohort of 342 patients. The performance of this model was validated using the concordance index (C-index) in a validation cohort of 147 patients. Another model was constructed using clinical variables, dosimetric parameters, and radiomic features for comparisons. Kaplan-Meier curves with log-rank analysis were used to assess the univariate discrimination based on the predictive dosiomic features. RESULTS: The dosiomic feature derived from the CTV was significantly associated with BCR (hazard ratio, 0.73; 95% CI, 0.57-0.93; P = .01). Although the dosiomics model outperformed the dosimetric and radiomics models, it did not outperform the clinical model. The performance significantly improved by combining the clinical variables and dosiomic features (C-index: 0.67; 95% CI, 0.65-0.68; P < .0001). The predictive dosiomic features were used to distinguish high-risk and low-risk patients (P < .05). CONCLUSIONS: The dosiomic feature extracted from the CTV was significantly correlated with BCR in patients with prostate cancer, and the dosiomics model outperformed the model with conventional dose indices. Hence, new metrics for evaluating the quality of a treatment plan are warranted. Moreover, further research should be conducted to determine whether dosiomics can be incorporated in a clinical workflow or clinical trial.

Progression of degenerative changes of the biceps tendon after successful rotator cuff repair.

BACKGROUND: This study investigated the morphologic changes in the biceps tendon using ultrasonography before and after successful arthroscopic posterosuperior rotator cuff repair. METHODS: Forty-four patients (44 shoulders) underwent arthroscopic posterosuperior rotator cuff repair with 1-year postoperative magnetic resonance imaging (MRI) follow-up. The patients comprised 22 men and 22 women with an average age of 61 years. The cross-sectional area (CSA) of the biceps tendon in the bicipital groove was measured, and the vascularity in the bicipital groove was graded as 0 to 3, based on the signal density of the anterior circumflex artery, using power Doppler ultrasonography. The preoperative and postoperative CSA and vascularity grades were compared. The pain score on the University of California, Los Angeles Shoulder Rating Scale was used to analyze the correlation between vascularity and postoperative pain. RESULTS: The average preoperative and postoperative CSA of the biceps tendon was 15.4 ± 6.5 and 17.9 ± 7.5 mm2, respectively. The postoperative CSA was significantly larger than the preoperative CSA (P < .01). Although no significant difference in the vascularity of the bicipital groove was observed between preoperative and postoperative grading, a negative correlation was observed between the vascularity and postoperative pain score on the University of California, Los Angeles scale (r = -0.369). CONCLUSIONS: The biceps tendon in the bicipital groove becomes thicker over time, even after successful posterosuperior rotator cuff repair. In addition, an increase in the vascularity around the biceps tendon in the groove is correlated with pain symptoms after successful repair.