MATERIALS AND METHODS: The study was performed on Varian Clinac iX, Elekta Synergy S, Siemens Oncor, and Tomotherapy. A CT phantom (Catphan-504, Phantom Laboratory, Salem, NY) was scanned for measurements of image quality including image noise, uniformity, density accuracy, spatial resolution, contrast linearity, and contrast resolution. The measurement results were analysed using in-house image analysis software. Reproducibility, position correction, and geometric accuracy were also evaluated with markers in a smaller alignment phantom. The performance evaluation compared volumetric image properties from these four systems with those from a conventional diagnostic CT (CCT).
RESULTS: It was shown that the linearity of the two kV CBCT was fairly consistent with CCT. The Elekta CBCT with half-circle 27-cm FOV had higher CT numbers than the other three systems. The image noises of the Elekta kV CBCT, Siemens MV CBCT, and Tomotherapy fan-beam CT (FBCT) are about 2-4 times higher than that of the Varian CBCT. The spatial resolutions of two kV CBCTs and two MV CBCTs were 8-11 lp/cm and 3-5 lp/cm, respectively.
CONCLUSION: Elekta CBCT provided a faster image reconstruction and low dose per scan for half-circle scanning. Varian CBCT had relatively lower image noise. Tomotherapy FBCT had the best uniformity.
Methods: We developed a patient-centered PrEP DA for women in addiction treatment. In a pilot randomized preference trial, we compared the DA to enhanced standard of care (eSOC) providing standardized information. The primary outcome was opting to receive more information through the DA; we also assessed the impact of the DA on PrEP decisional preference and PrEP uptake over 12 months.
Results: A total of 164 enrolled participants (DA: 83; eSOC: 81) were similar in terms of HIV risk and demographics, which are representative of women in addiction treatment programs nationally, and most (92%) had opioid use disorder. Half of participants were PrEP eligible, though 37% underestimated their personal HIV risk. Independent correlates of selecting the PrEP DA relative to eSOC included higher alcohol use severity (aOR 4.13, 95% CI 1.05-16.28, p=0.04) and perception of high risk for HIV (aOR 2.95, 95% CI 1.19-7.35, p=0.02). For those selecting the DA, interest in PrEP increased significantly from 25% to 89%. DA participants were also significantly more likely than eSOC participants to see a provider for PrEP during follow-up (15.7% vs 6.2%; p=0.05).
Conclusion: Half of the women selected to use the DA, and those who did significantly increased their engagement in the HIV prevention cascade through increased interest in and initiation of PrEP. Future iterations should accelerate the HIV prevention cascade for women with SUDs by integrating PrEP decision aids into existing addiction treatment services and actively linking women to PrEP.