Updated Trends in Cervical Cancer Brachytherapy Utilization and Disparities in the United States From 2004 to 2020.

PURPOSE: Lower brachytherapy utilization for cervical cancer patients is associated with decreased survival. This study examines more recent trends in brachytherapy utilization from 2004 to 2020 to assess any trend reversal after awareness increased regarding the importance of brachytherapy. METHODS AND MATERIALS: This study analyzed data from the National Cancer Database of patients with Federation of Gynecology and Obstetrics (FIGO) IB to IVA cervical cancer treated with radiation therapy between 2004 and 2020. To compare brachytherapy utilization over time, 2- to 3-year categories were created to account for potential variation seen in individual years. A multivariate log binomial regression with robust variance was used to estimate the incidence rate ratio (IRR) of brachytherapy utilization in each year category in reference to the 2004-2006 category. Additionally, risk factors for brachytherapy utilization were identified. RESULTS: Overall brachytherapy utilization for cervical cancer increased from 54.9% in 2004 to 75.7% in 2020. Compared with 2004 to 2006 when rates of utilization totaled 55.2%, brachytherapy utilization significantly increased to 63.4% in 2011 to 2014 (IRR, 1.15; 95% CI, 1.11-1.19), 66.0% in 2015 to 2017 (1.20 [1.16-1.23]), and 76.0% in 2018 to 2020 (1.38 [1.34-1.42]). Sociodemographic factors associated with lower brachytherapy utilization included Black race (0.94 [0.92-0.97]), Hispanic ethnicity (0.92 [0.90-0.95]), and age >59 years (age ≥60-69: 0.96 [0.94-0.98]; age ≥70-79: 0.89 [0.87-0.92]; age ≥80: 0.73 [0.69-0.77]). Positive predictors of brachytherapy utilization included having insurance (IRR, 1.11; 95% CI, 1.07-1.14). CONCLUSIONS: In patients with FIGO IB-IVA cervical cancer treated with radiation therapy from 2004 to 2020, brachytherapy utilization has increased during the past decade. These results are encouraging given the known benefit to cause-specific survival and overall survival provided by brachytherapy treatment and indicate a reversal in the trend of declining brachytherapy noted previously. Concerns related to disparities by race, ethnicity, and insurance status require further interventions.

Singular value decomposition analysis of a photoacoustic imaging system and 3D imaging at 0.7 FPS.

Photoacoustic imaging is a non-ionizing imaging modality that provides contrast consistent with optical imaging techniques while the resolution and penetration depth is similar to ultrasound techniques. In a previous publication [Opt. Express 18, 11406 (2010)], a technique was introduced to experimentally acquire the imaging operator for a photoacoustic imaging system. While this was an important foundation for future work, we have recently improved the experimental procedure allowing for a more densely populated imaging operator to be acquired. Subsets of the imaging operator were produced by varying the transducer count as well as the measurement space temporal sampling rate. Examination of the matrix rank and the effect of contributing object space singular vectors to image reconstruction were performed. For a PAI system collecting only limited data projections, matrix rank increased linearly with transducer count and measurement space temporal sampling rate. Image reconstruction using a regularized pseudoinverse of the imaging operator was performed on photoacoustic signals from a point source, line source, and an array of point sources derived from the imaging operator. As expected, image quality increased for each object with increasing transducer count and measurement space temporal sampling rate. Using the same approach, but on experimentally sampled photoacoustic signals from a moving point-like source, acquisition, data transfer, reconstruction and image display took 1.4 s using one laser pulse per 3D frame. With relatively simple hardware improvements to data transfer and computation speed, our current imaging results imply that acquisition and display of 3D photoacoustic images at laser repetition rates of 10Hz is easily achieved.

Localization of spherical lesions in tumor-mimicking phantoms by 3D sparse array photoacoustic imaging.

PURPOSE: The authors have developed a sparse-array photoacoustic imaging (SPAI) system that is capable of mapping 3D distributions of optical absorption using a small number of laser pulses with no mechanical scanning needed. In previous studies, the authors have shown the localization accuracy and the high frame-rate image acquisition on simple phantoms with limited medical relevance. The purpose of this study was to test the imaging capabilities of SPAI in the context of breast tumor detection and localization. METHODS: The authors constructed an array of phantoms that include spherical lesions of sizes 1.5-9 mm, buried in highly scattering tissue phantoms at depths of 3-30 mm. The authors investigated both homogeneous lesions made of blood at varying concentrations and heterogeneous lesions containing vessel-like structures. Volumetric images of the deeply buried lesions were taken at increasingly shallower depths and image-based localization was compared to measured depth. RESULTS: The authors were able to detect and accurately localize homogeneous lesions having a realistic absorption coefficient of 0.2 cm(-1) down to depths of 9-20 mm, and heterogeneous lesions containing 0.5 mm diameter vessel-like structures down to depths of 13-20 mm. Image acquisition required 2.5 s for each volumetric lesion image. CONCLUSIONS: These results suggest that 3D SPAI can detect highly vascularized lesions well below 1 cm in diameter and can overcome optical scatter of tissue to depths of 1-2 cm. With further improvement in the sensitivity and noise characteristics of the imaging system, similar imaging depths should be within reach in real breast tissue. The method, due to its optical contrast, 3D imaging, and fast acquisition, may prove useful in the clinic as an adjunct to existing breast screening tools.