The electron beams for total skin electron therapy (TSET) are often degraded by a scatter plate in addition to extended distances. For electron dosimetry, both the AAPM TG-51 and IAEA TRS-398 recommend the use of two formulas developed by Burns et al [Med. Phys. 23, 489-501 (1996)] to estimate the water-to-air stopping-power ratios (SPRs). Both formulas are based on a fit to SPRs calculated for standard electron beams. This study aims to find (1) if the formulas are applicable to beams used in TSET and (2) the impact of the ICRU report 90 recommendations on the SPRs for these beams.

The EGSnrc Monte Carlo code system is used to generate 6MeV high dose rate total skin electron (HDTSe) beams used in TSET. The simulated beams are used to calculate dose distributions and SPRs as a function of depth in a water phantom. The fitted SPRs using the empirical formulas are compared with MC-calculated SPRs.

The electron beam quality specifier, the depth in water at which the absorbed dose falls to 50% of its maximuof a percent for beams used in TSET.

The formulas used by the major protocols are accurate enough for clinical beams used in TSET and the error caused using the formulas is less then 1% to estimate SPRs as a function of depth and R50 for depths less then 0.8R50 for beams used in TSET with R50 ≥ 1.14 cm. The impact of the ICRU-90 recommendations shows a decrease of SPRs by a fraction of a percent for beams used in TSET.

To test in vivo a new design prototype for radio frequency (RF) ablation.

A prototype based on a concept of endo-epicardial biparietal bipolar RF ablation with the atrial tissue interposed and consisting of two specular endocardial-epicardial catheters was tested in four pigs (80±5kg). The endocardial catheter was introduced into the left atrium through the left atrial appendage on the beating heart. The epicardial counterpart was placed manually on the atrial epicardial surface. The coupling of the two catheters was achieved using a neodymium magnet around the gold plate electrode, and RF was applied to the interposed tissue. The hearts were excised, and the lesions were examined using morphometric evaluation.

The RF application resulted in transmural lesions in all of the four animals tested. learn more In these animals the maximum endocardial width (W

) was 6.34 ± 0.25, 6.54 ± 0.33, 6.36 ± 0.57, and 6.49 ± 0.96mm. The pericardial width (W

) was similar 6.37 ± 0.47, 6.58 ± 0.32, 6.35 ± 0.56 and 6.53 ± 0.94mm. The lesion area was 924.78, 949.25, 944.25, and 926.05 mm

, and the lesion volume was 92.47, 94.92, 94.42, and 92.60 mm

, respectively.

The idea of an endocardial-epicardial bidirectional biparietal bipolar radiofrequency tool such that the atrial tissue is fully interposed between the two RF poles might be promising for future clinical applications. Further research is warranted.

The idea of an endocardial-epicardial bidirectional biparietal bipolar radiofrequency tool such that the atrial tissue is fully interposed between the two RF poles might be promising for future clinical applications. Further research is warranted.

Spectral distortion due to charge sharing (CS) and pulse pileup (PP) in photon-counting detectors (PCDs) degrades the quality of PCD data. We recently proposed multi-energy inter-pixel coincidence counters (MEICC) that provided spectral cross-talk information related to CS. When PP was absent, the normalized Cramér-Rao lower bounds (nCRLBs) of 225-µm pixel PCDs with MEICC was comparable to those of 450-µm pixel PCD without MEICC. The aim of this study was to assess the performance of PCDs with MEICC in the presence of both CS and PP using computer simulations.

An in-house Monte Carlo program was modified to incorporate the following four temporal elements (1) A pulse shape with a pulse duration of 20ns, (2) delays of up to 10ns in anode arrival times when photons were incident on pixel boundaries, (3) offsets proportional to a vertical separation between the primary and secondary charge clouds at the rate of ±4ns per ±100µm, and (4) a stochastic fluctuation of anode arrival times for all of the charge clo 1mA. PP decreased the merit of MEICC over the conventional PCD in addressing CS. Nonetheless, MEICC consistently provided better nCRLBs than the conventional PCD did. The nCRLBs of MEICC were in the range of 49-58% of those of the conventional PCD for K-edge imaging, 45-76% for water-bone material decomposition, and 81-88% for the conventional CT imaging (i.e., linear attenuation coefficient maps). ACS provided better nCRLBs than the conventional PCD did only when the effect of PP was minor (e.g., when the counting efficiency of the conventional PCD was higher than 0.95 with the tube current of up to 100mA).

Besides a few cases, MEICC provides the best nCRLBs for all of the tasks at all of the count rates. ACS and DCS provide better nCRLBs than the conventional PCD does only when count rates are very low.

Besides a few cases, MEICC provides the best nCRLBs for all of the tasks at all of the count rates. ACS and DCS provide better nCRLBs than the conventional PCD does only when count rates are very low.

The risk of bloodstream infections may be increased in hospitalized patients receiving ready-made parenteral nutrition (PN) multichamber bags (MCBs) compared with customized PN; however, as highlighted in recent international guidelines, there are no comparable data relating to home PN (HPN).

Data from a prospectively maintained database were analyzed to compare incidence rates of catheter-related bloodstream infections (CRBSIs) between patients receiving customized HPN compared with MCB HPN at a national UK referral center between May 2018 and August 2020.

Sixty patients with chronic intestinal failure were commenced on MCBs and 45 received customized HPN for a total of 5914 and 7641 catheter days, respectively. No difference in CRBSI incidence was found (0.51/1000 catheter days for MCBs, 0.39/1000 catheter days for customized HPN; incidence rate ratio, 1.29; 95% CI, 0.26-6.37). Eighteen patients were switched from customized HPN to MCB HPN. The study period covered 7401 catheter days receiving customized HPN and 4834 days on MCBs.