Abstract. Light dosimetry is an important parameter that affects the efficacy of photodynamic therapy (PDT). However, the irregular morphologies of lesions complicate lesion segmentation and light irradiance adjustment. Therefore, this study developed an illumination demo system comprising a camera, a digital projector, and a computing unit to solve these problems. A three-dimensional model of a lesion was reconstructed using the developed system. Hierarchical segmentation was achieved with the superpixel algorithm. The expected light dosimetry on the targeted lesion was achieved with the proposed illumination procedure. Accurate control and optimization of light delivery can improve the efficacy of PDT.

No abstract

BackgroundPulmonary hemorrhage (PH) in neonates is a life-threatening respiratory complication. We aimed to analyze the perinatal risk factors and morbidity with PH among very preterm infants in a large multicenter study.MethodsThis was a multicenter case–control study based on a prospective cohort. Participants included 3,680 in-born infants with a gestational age at 24–32 weeks (birth weight <1,500 g) who were admitted between January 1, 2019, and October 31, 2021. All infants were divided into two groups, namely, the PH and no-PH groups, at a ratio of 1:2 according to the following factors: gestational age (GA), birth weight (BW), and the Score for Neonatal Acute Physiology with Perinatal extension II (SNAPPE II). Perinatal factors and outcomes were compared between the two groups by logistic regression analyses.ResultsA total of 3,680 infants were included in the study, and the number of identified cases of PH was 262 (7.1%). The incidence was 16.9% (136/806) for neonates with extremely low BW (BW < 1,000 g) infants. The multivariate analysis showed that CPAP failure (OR 2.83, 95% CI 1.57, 5.08) was significantly associated with PH. PH was associated with a high likelihood of death (OR 3.81, 95% CI 2.67, 5.43) and bronchopulmonary dysplasia (BPD) (≥grade II) (OR 1.58, 95% CI 1.00, 2.48).ConclusionsIn this multicenter case–control study based on a prospective cohort, PH to be common among VLBW infants. PH is associated with significant morbidity and mortality, and perinatal management, especially CPAP failure. Respiratory management strategies to decrease the risk of PH should be optimized.

Controllable and effective irradiation of lesions is among the key factors that affect the potency of photodynamic therapy (PDT). An optimization method for the irradiance distribution of treatment was proposed which can be used to improve the efficacy of PDT and allow more lesions to receive the desired irradiance level in a single therapy session. With the proposed digital illumination binocular treatment system, the preferred surface normal vectors, irradiation angles, as well as area and weight coefficients of lesions can be achieved and used as characteristic parameters to optimize the irradiation direction. Two port-wine stain phantom experiments were performed. The comparison of the illumination area between preoptimization and postoptimization showed that the proposed method can effectively guide the light source control, improve the distribution of light dose, and increase the effective treatment area.