No abstract

Although blood-based liquid biopsies have emerged as a promising non-invasive method to detect biomarkers in various cancers, limited progress has been made for brain tumors. One major obstacle is the blood-brain barrier (BBB), which hinders efficient passage of tumor biomarkers into the peripheral circulation. The objective of this study was to determine whether FUS in combination with microbubbles can enhance the release of biomarkers from the brain tumor to the blood circulation. Two glioblastoma tumor models (U87 and GL261), developed by intracranial injection of respective enhanced green fluorescent protein (eGFP)-transduced glioblastoma cells, were treated by FUS in the presence of systemically injected microbubbles. Effect of FUS on plasma eGFP mRNA levels was determined using quantitative polymerase chain reaction. eGFP mRNA were only detectable in the FUS-treated U87 mice and undetectable in the untreated U87 mice (maximum cycle number set to 40). This finding was replicated in GL261 mice across three different acoustic pressures. The circulating levels of eGFP mRNA were 1,500–4,800 fold higher in the FUS-treated GL261 mice than that of the untreated mice for the three acoustic pressures. This study demonstrated the feasibility of FUS-enabled brain tumor liquid biopsies in two different murine glioma models across different acoustic pressures.

Respiration, cardiac, and digestive-related motion pose challenges to MR thermometry of the chest wall and bladder wall. The leg muscles had satisfactory temperature accuracy and precision per the chosen criteria. These results indicate that extremity locations may be preferable targets for MR-guided MHT using the existing MR thermometry technique.

IntroductionFluoroscopy is essential in percutaneous nephrolithotomy (PCNL) but exposes patients and operating room staff to radiation. We investigated whether a low-dose (LD) protocol could reduce radiation exposure during uoroscopy-guided access without compromising clinical outcomes. MethodsPatients undergoing PCNL with uoroscopy-guided access at a tertiary care stone center between January 2019 to July 2021 were identi ed. Prior to September 3, 2020, the Philips Veradius C-arm's default settings were used: standard per-frame dose, 15 pulses per second (PPS) frame rate. After this date, a low-dose protocol was used: reduced per-frame dose, reduced frame rate of 8 PPS for needle puncture and 4 PPS for all other steps. Clinical and radiographical data were retrospectively collected. The primary outcome was cumulative radiation dose. Secondary outcomes were stone-free status (SFS; de ned as no fragments ³2mm) and complications. Multivariate regression analysis was performed.Results 100 patients were identi ed; 31 were in the LD group. The LD cohort was exposed to a signi cantly lower mean cumulative radiation dose of 11.68 mGy compared to 48.88 mGy (p<0.0001). There were no differences in operative time, uoroscopy time, stone burden, SFS or complications. In a multivariable regression model adjusting for several variables, LD protocol was associated with lower radiation dose while skin-to-calyx-distance (STCD) was positively associated with cumulative radiation dose. Higher preoperative stone burden was associated with longer operative time (p=0.0001) and lower odds of postoperative SFS (odds ratio=0.959, p=0.0007). ConclusionsLow-dose uoroscopy and decreased frame rate during PCNL decreased radiation exposure four-fold without affecting SFS or complication rates.

IntroductionFluoroscopy is essential in percutaneous nephrolithotomy (PCNL) but exposes patients and operating room staff to radiation. We investigated whether a low-dose (LD) protocol could reduce radiation exposure during fluoroscopy-guided access without compromising clinical outcomes.MethodsPatients undergoing PCNL with fluoroscopy-guided access at a tertiary care stone center between January 2019 to July 2021 were identified. Prior to September 3, 2020, the Philips Veradius C-arm’s default settings were used: standard per-frame dose, 15 pulses per second (PPS) frame rate. After this date, a low-dose protocol was used: reduced per-frame dose, reduced frame rate of 8 PPS for needle puncture and 4 PPS for all other steps. Clinical and radiographical data were retrospectively collected. The primary outcome was cumulative radiation dose. Secondary outcomes were stone-free status (SFS; defined as no fragments ³2mm) and complications. Multivariate regression analysis was performed.Results100 patients were identified; 31 were in the LD group. The LD cohort was exposed to a significantly lower mean cumulative radiation dose of 11.68 mGy compared to 48.88 mGy (p<0.0001). There were no differences in operative time, fluoroscopy time, stone burden, SFS or complications. In a multivariable regression model adjusting for several variables, LD protocol was associated with lower radiation dose while skin-to-calyx-distance (STCD) was positively associated with cumulative radiation dose. Higher preoperative stone burden was associated with longer operative time (p=0.0001) and lower odds of postoperative SFS (odds ratio=0.959, p=0.0007).ConclusionsLow-dose fluoroscopy and decreased frame rate during PCNL decreased radiation exposure four-fold without affecting SFS or complication rates.