Survey of imaging dose in HDR brachytherapy

Institutional imaging protocols for the verification of brachytherapy applicator placements were investigated in a survey study of domestic radiotherapy institutions. The survey form designed by a free on-line survey system was distributed via the mailing-list system of the Japanese Society for Radiation Oncology. Survey data of 75 institutions between August 2019 and October 2019 were collected. The imaging modalities used were dependent on resources available to the institutions. The displacement of a brachytherapy applicator results in significant dosimetric impact. It is essential to verify applicator placements using imaging modalities before treatment. Various imaging modalities used in institutions included a computed tomography (CT) scanner, an angiography X-ray system, a multi-purpose X-ray system and a radiotherapy simulator. The median total exposure time in overall treatment sessions was ≤75 s for gynecological and prostate cancers. Some institutions used fluoroscopy to monitor the brachytherapy source movement. Institutional countermeasures for reducing unwanted imaging dose included minimizing the image area, changing the imaging orientation, reducing the imaging frequency and optimizing the imaging conditions. It is worth noting that half of the institutions did not confirm imaging dose regularly. This study reported on the usage of imaging modalities for brachytherapy in Japan. More caution should be applied with interstitial brachytherapy with many catheters that can lead to potentially substantial increments in imaging doses for monitoring the actual brachytherapy source using fluoroscopy. It is necessary to share imaging techniques, standardize imaging protocols and quality assurance/quality control among institutions, and imaging dose guidelines for optimization of imaging doses delivered in radiotherapy should be developed

Change in plasma lactate concentration during arctigenin administration in a phase I clinical trial in patients with gemcitabine-refractory pancreatic cancer.

Arctigenin is evaluated for antitumor efficacy in patients with pancreatic cancer. It has an inhibitory activity on mitochondrial complex I.Therefore, plasma lactate level of patients after arctigenin administration was evaluated for biomarker of clinical response and/or adverse effect. Plasma lactate level in 15 patients enrolled in a Phase I clinical trial of GBS-01 rich in arctigenin was analyzed by colorimetric assay. Statistical analyses for association of plasma lactate and clinical responses, pharmacokinetics of arctigenin, and background factors of each patient by multivariate and univariate analyses.In about half of the patients, transient increase of lactate was observed. Correlation between plasma lactate level and pharmacokinetic parameters of arctigenin and its glucuronide conjugate, and clinical outcome was not detected. Regarding to the determinant of lactate level, only slight association with liver function test was detected. Plasma lactate level is primary determined by reutilization rather than production for antitumor effect and dose not serve as a biomarker. Arctigenin, inhibition of mitochondrial complex I, plasma lactate concentration, phase I clinical trial of GBS-01, Cori cycle

Correlation analyses of plasma lactate AUC and AUC of AG or AGG.

<p>Correlation analyses of plasma lactate AUC and AUC of AG or AGG.</p

Individual variation of plasma lactate maximal concentration and plasma lactate AUC.

<p>A, Correlative plots of plasma lactate level before and after AG administration. Cmax of lactate was used as lactate concentration after AG administration. B, Lactate AUC was plotted.</p

Radiation protection in radiological imaging: a survey of imaging modalities used in Japanese institutions for verifying applicator placements in high-dose-rate brachytherapy.

Institutional imaging protocols for the verification of brachytherapy applicator placements were investigated in a survey study of domestic radiotherapy institutions. The survey form designed by a free on-line survey system was distributed via the mailing-list system of the Japanese Society for Radiation Oncology. Survey data of 75 institutions between August 2019 and October 2019 were collected. The imaging modalities used were dependent on resources available to the institutions. The displacement of a brachytherapy applicator results in significant dosimetric impact. It is essential to verify applicator placements using imaging modalities before treatment. Various imaging modalities used in institutions included a computed tomography (CT) scanner, an angiography X-ray system, a multi-purpose X-ray system and a radiotherapy simulator. The median total exposure time in overall treatment sessions was $\le$75 s for gynecological and prostate cancers. Some institutions used fluoroscopy to monitor the brachytherapy source movement. Institutional countermeasures for reducing unwanted imaging dose included minimizing the image area, changing the imaging orientation, reducing the imaging frequency and optimizing the imaging conditions. It is worth noting that half of the institutions did not confirm imaging dose regularly. This study reported on the usage of imaging modalities for brachytherapy in Japan. More caution should be applied with interstitial brachytherapy with many catheters that can lead to potentially substantial increments in imaging doses for monitoring the actual brachytherapy source using fluoroscopy. It is necessary to share imaging techniques, standardize imaging protocols and quality assurance/quality control among institutions, and imaging dose guidelines for optimization of imaging doses delivered in radiotherapy should be developed

Multivariate analysis between AUC of lactate and renal and liver function in 15 patients.

<p>Multivariate analysis between AUC of lactate and renal and liver function in 15 patients.</p

Time-dependent change in plasma lactate in patients in GBS-01 phase I clinical trial (UMIN000005787).

<p>Patients was orally administrated GBS-01 corresponding to 100 mg (level 1), 250mg (level 2) and 400mg (level 3) equivalent of arctigenin. Number of patients were 3, 3 and 9 in level 1, level 2, and level 3, respectively. Each point represents mean and arrows represent standard deviation.</p

Effect of AG on lactate production by PANC-1 cells and on mitochondrial respiration.

<p>A. Lactate concentration in culture media in the absence and presence of AG at 1 μM. Lactate concentration in the medium was sequentially determined by lactate assay kit II. B. Effect of AG on OCR of PANC-1 cells was examined with a Seahorse Extracellular Flux Analyzer model 24XF. Mitochondrial stress test was carried out by inhibiting complex V activity by 1 μM oligomycin, and maximizing respiration was maximized by addition of 1 μM Carbonyl cyanide-p- trifluoromethoxyphenylhydrazone (FCCP). Effect of AG was then examined on the maximized respiration.</p

Correlation analyses among plasma lactate AUC and laboratory tests.

<p>WBC, CRP, FBS, ALB, T-BIL, AST, ALT, γGTP, ALP, CRE, CCr and BUN.</p