Most total pancreatectomies for ductal adenocarcinoma potentially can Be replaced by whipple over the splenic artery: a before and after study.

INTRODUCTION: Recently, more and more total pancreatectomy (TP) has been performed for central-located pancreatic ductal cell adenocarcinoma (PDCA) which abuts or involves both gastroduodenal and splenic arteries and demands transaction of both of them for a complete resection. Spiked by Warshaw's procedure (spleen-preserving distal pancreatectomy with excision of splenic vessels), we developed a new procedure "Whipple over the splenic artery (WOTSA)" to replace TP by leftward extension of pancreatic parenchyma transaction line and preservation of pancreatic tail and spleen after excision of splenic artery. This uncontrolled before and after study assesses the safety and efficacy of a new technique "Whipple over the splenic artery (WOTSA)" as a treatment for PDAC which traditionally requires total pancreatectomy (TP) for a complete excision. METHODS: The study group comprised 40 consecutive patients who underwent WOTSA for PDAC between August 2019 and September 2022. Their clinicopathological characteristics and survival were compared with those of a historical control group comprising 30 consecutive patients who underwent TP between January 2016 and July 2019. RESULTS: None of the 40 patients in the WOTSA group required reoperation due to infarction of the pancreas and/or spleen remnant. DM medication after WOTSA were none in 19, oral hypoglycemic agents in 19, and insulin preparations in 2 patients. Compared with TP, patients who underwent WOTSA exhibited similar rates of major operative complications, clear pancreatic parenchyma transaction margin, and number of harvested positive lymph nodes, but higher rate of adjuvant chemotherapy completion and a trend toward better median disease free survival (14 vs. 7.5 mo, P=0.023). CONCLUSIONS: Compared to TP, WOTSA can be safely performed and have much better postoperative glycemic status without cost of higher operative risk or impaired surgical radicality. These findings indicate that most TPs for PDAC potentially can be replaced by WOTSAs.

MOSFET dose measurements for proton SOBP beam.

PURPOSE: The aim of this work was to develop a computational scheme for the correction of the LET dependence on the MOSFET response in water phantom dose measurements for a spread-out Bragg peak (SOBP) proton beam. METHODS: The LET dependence of MOSFET was attributed to the stopping power ratio of SiO2 to H2O and to the fractional hole yield in the SiO2 layer. Using literature values for the stopping powers of the continuous slowing down approximation and measured fractional hole yields vs. electric field and LET, formulas were derived for the computation of a dose-weighted correction factor of a SOBP beam. RESULTS: Dose-weighted correction factors were computed for a clinical 190-MeV proton SOBP beam in a high-density polyethylene phantom. By applying correction factors to the SOBP beam, which consisted of weighted monoenergetic Bragg peaks, the MOSFET outputs were predicted and agreed well with the measured MOSFET responses. CONCLUSION: By applying LET dependent correction factors to MOSFET data, quality assurance of dose verification based on MOSFET measurements becomes possible for proton therapy.