Abstract Introduction: A dosimetric performance analysis of microDiamond (MD) detector in magnetic resonance imaging linear accelerators (MR-Linac) was performed to evaluate its utility for patient-specific quality assurance (PSQA) in stereotactic radiotherapy (SRT). Methods: Output factors (OFs), depth dose curves, and dose profiles for field sizes from 1 cm × 1 cm to 10 cm × 10 cm were measured in an Elekta Unity 1.5 T MR-Linac. Measurements were conducted using an MR-Safe three-dimensional (3D) water phantom with a PTW Semiflex 3D ionization chamber and a PTW MD detector. Angular response was assessed for orientations perpendicular to the beam and parallel to the magnetic field; correction factors were determined for gantry angles from 0° to 360° in 20° increments. Detectors were cross-calibrated against a 0.6 cc Farmer chamber, and patient-specific point-dose verification was performed for SRT plans. Results: Average d max measured with the MD detector (1.28 ± 0.1 cm) agreed closely with the Semiflex 3D (1.27 ± 0.1 cm). The Semiflex 3D overestimated penumbra by 1.8 ± 0.6 mm and underestimated small-field OFs, while the MD detector showed slight overresponse (0.5%). The angular dependence remains substantial and highly sensitive to field size, requiring field-size-specific angular correction factors to achieve clinical accuracy better than 2%. After cross-calibration, the difference between the measured and planned doses for the 1.2 cc target was − 6.92% for Semiflex 3D and 1.36% for MD detector. Conclusion: The MD detector was successfully validated for MR-Linac. Asymmetric angular dependence due to the Lorentz force was confirmed, necessitating gantry angle-specific corrections for dose estimation. The MD detector demonstrated superior accuracy for small-field SRT targets, confirming its significance for precise PSQA.
Acute pelvic pain is defined as noncyclic, intense pain localized to the lower abdomen and/or pelvis, with a duration of less than three months. Signs and symptoms are often nonspecific. The differential diagnosis is broad, based on the patient's age and pregnancy status and gynecologic vs. nongynecologic etiology. Nongynecologic etiologies include gastrointestinal, urinary, and musculoskeletal conditions. Urgent gynecologic conditions include ectopic pregnancy, ruptured ovarian cyst, adnexal torsion, and pelvic inflammatory disease. Approximately 40% of ectopic pregnancies are misdiagnosed at the presenting visit. Urgent nongynecologic conditions include appendicitis and pyelonephritis. Less urgent etiologies include sexually transmitted infections, pelvic floor myofascial pain, dysmenorrhea, and muscle strain. Approximately 15% of untreated chlamydia infections lead to pelvic inflammatory disease. History and physical examination findings guide laboratory testing. Questions should focus on the type, onset, location, and radiation of pain; timing and duration of symptoms; aggravating and relieving factors; and associated symptoms. Performing a urine pregnancy test or beta human chorionic gonadotropin test is an important first step for sexually active, premenopausal patients. Imaging options should be considered, with transvaginal ultrasonography first, followed by computed tomography. Magnetic resonance imaging can be useful if ultrasonography and computed tomography are nondiagnostic.
This Viewpoint discusses the American Academy of Pediatrics Obesity Guidelines.
Introduction Physicians' perspectives regarding the etiology of racial health differences may be associated with their use of race in clinical practice (race-based practice). This study evaluates whether attributing racial differences in health to genetics, culture, or social conditions is associated with race-based practice. Methods This is a cross-sectional analysis, conducted in 2022, of the Council of Academic Family Medicine Education Research Alliance 2021 general membership survey. Only actively practicing U.S. physicians were included. The survey included demographic questions; the Racial Attributes in Clinical Evaluation (RACE) scale (higher scores imply greater race-based practice); and 3 questions regarding beliefs that racial differences in genetics, culture (e.g., health beliefs), or social conditions (e.g., education) explained racial differences in health. Three multivariable linear regressions were used to evaluate the relationship between RACE scores and beliefs regarding the etiology of racial differences in health. Results Of the 4,314 survey recipients, 949 (22%) responded, of whom 689 were actively practicing U.S. physicians. In multivariable regressions controlling for age, gender, race, ethnicity, and practice characteristics, a higher RACE score was associated with a greater belief that differences in genetics (β=3.57; 95% CI=3.19, 3.95) and culture (β=1.57; 95% CI=0.99, 2.16)—in but not social conditions—explained differences in health. Conclusions Physicians who believed that genetic or cultural differences between racial groups explained racial differences in health outcomes were more likely to use race in clinical care. Further research is needed to determine how race is differentially applied in clinical care on the basis of the belief in its genetic or cultural significance.
