Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)]

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

[Dosimetric Properties of Brass Mesh Bolus for High-energy Photon Beam]

PURPOSE

To investigate fundamental dosimetric properties of surface dose, exit dose, and beam profile of the brass mesh bolus for 4, 6, and 10 MV high-energy photon beams in radiation therapy.

METHODS

Surface dose and exit dose in the water-equivalent phantom were measured, and percent depth doses (PDDs) were calculated with no bolus, one layer of brass mesh, two layers of brass mesh bolus, three layers of brass mesh bolus, and 0.5 cm tissue-equivalent (TE) bolus. Exit dose was measured at a phantom thickness of 10 cm. Beam profiles were measured at phantom depths of 0 cm and 10 cm. All dosimetry was performed for 4, 6, and 10 MV photon beams using a linear accelerator.

RESULTS

The surface dose at a phantom depth of 0 cm increased to 37.3%, 36.3%, and 31.0% for 4, 6, and 10 MV, respectively, with the brass mesh bolus compared to the case of no bolus. The surface dose decreased with one layer of brass mesh bolus compared to that with the 0.5 cm TE bolus. On the other hand, the exit dose increased to 22.0%, 23.1%, and 22.8% for 4, 6, and 10 MV, respectively, with the brass mesh bolus compared to the case of no bolus. The beam profile at the depth of 0 cm showed oscillations, and the difference between the maximum and minimum doses was up to 13.1% with one layer of brass mesh bolus.

CONCLUSION

It was suggested that the brass mesh bolus not only increases the surface dose but also has different properties from the conventional TE bolus.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande

We report a search for cosmic-ray boosted dark matter with protons using the 0.37  megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1  MeV/c^{2} to 300  MeV/c^{2}.

Correction to: Development of a new phantom simulating extracellular space of tumor cell growth and cell edema for diffusion-weighted magnetic resonance imaging

The original version of this article unfortunately contained a mistake. Second column of "Cell edema" should read as.

Outcome of maintenance systemic chemotherapy with drug-free interval for metastatic urothelial carcinoma

OBJECTIVE

Aiming to achieve long-term disease control, maintenance systemic chemotherapy (MSC) with a 1-3-month drug-free interval is continued in selected patients. We report our experience of MSC for metastatic urothelial carcinoma (UC).

METHODS

Of 228 metastatic UC patients treated with systemic chemotherapy, 40 (17.5%, 40/228) had continuously undergone MSC. Data on the regimen, cycle number, and reason for the discontinuation of MSC were also collected. We analyzed OS from the initiation of MSC until death or the last follow-up, using the log-rank test to assess the significance of differences.

RESULTS

The median number of cycles of chemotherapy was 6, and the responses were CR in 6, PR in 20, SD in 13, and PD in 1 before MSC. Gemcitabine plus CDDP or carboplatin was mainly performed as MSC (70%, 28/40). MSC was repeated quarterly in 30 (75%, 30/40), every two months in 8 (20%, 8/40), and with other intervals in 2 (5%, 2/40). Overall, a median of 3.5 cycles (range: 1-29) of MSC was performed. The reason for the discontinuation of MSC was PD in 24 (60%, 24/40), favorable disease control in 9 (22.5%, 9/40), and myelosuppression in 3 (7.5%, 3/40), and for other reasons in 2 (5%, 2/40). MSC was ongoing in 2 (5%, 2/40). The median OS was 27 months from the initiation of MSC. PS0 (P = 0.0169), the absence of lung metastasis (P = 0.0387), and resection of the primary site (P = 0.0495) were associated with long-term survival after MSC.

CONCLUSIONS

In selected patients, long-term systemic chemotherapy could be performed with a drug-free interval. Our maintenance strategy with cytotoxic drugs may become one of the treatment options for long-term disease control.

Dosimetric assessment of a single-energy metal artifact reduction algorithm for computed tomography images in radiation therapy

This study aimed to evaluate the performance of a single-energy metal artifact reduction (SEMAR) algorithm for radiation therapy treatment using phantom cases with metal inserts, assess improvements in computed tomography (CT) number accuracy, and investigate its effects on treatment planning dosimetry. A standard electron density phantom was scanned with and without metal inserts. The numbers of tissue-equivalent materials on both uncorrected and SEMAR-corrected CT images were compared. Treatment planning accuracy was evaluated by comparing dose distributions computed using true density images (without metal inserts), uncorrected images (with metal inserts), and SEMAR-corrected images (with metal inserts) using three-dimensional gamma analysis. The numbers of the true density and uncorrected and SEMAR-corrected CT images in a muscle plug with unilateral inserts were 25.9 HU, - 281.8 HU, and 26.1 HU, respectively. A similar tendency was obtained for other tissue-equivalent materials, and the numbers on CT images were improved with the SEMAR algorithm. In cases involving 1 portal irradiation, 10-MV X-ray, and the Acuros XB algorithm, the pass ratio between the true density and uncorrected images was 89.89%, while that between the true density and SEMAR-corrected images was 95.03%. Improvements in dose distribution were evident using the SEMAR algorithm. Similar trends were found for different irradiation methods and dose calculation algorithms. The SEMAR algorithm can significantly reduce metal artifacts on CT images used for radiation treatment planning. This aspect influenced dosimetry in the region of the artifact and dose distribution was significantly improved with use of the SEMAR-corrected images.

[Improvement of Image Quality in the Axial Section Using High-resolution Scan Mode and Hybrid Iterative Reconstruction in Ultra-high-resolution Computed Tomography]

The purpose of this study is to compare the physical characteristics and visibility of high-resolution and conventional images acquired with the same X-ray dose, and to investigate the superiority of super high-resolution imaging. A Catphan phantom was scanned in the normal resolution (NR), high-resolution (HR), and super high-resolution (SHR) modes of ultra-high-resolution computed tomography at 120 kV and 75 mAs. All images were reconstructed into a 5-mm thick image slices with filtered back-projection (FBP) and hybrid image reconstruction (HIR), which included normal and enhanced adaptive iterative dose reduction 3D (AIDR and eAIDR, respectively). The modulation transfer function (MTF) and noise power spectrum (NPS) were measured using the circular edge method and radial frequency method, respectively. The signal-to-noise ratio (SNR) was then calculated. High-contrast resolution and low-contrast detectability were evaluated visually by five radiological technologists. The MTFs of HR_eAIDR and HR_FBP images were higher than those of NR_FBP images. However, the NPSs of HR_eAIDR and HR_FBP images were larger than those of NR_FBP images. The SNR of HR_eAIDR images was higher than that of NR_FBP and HR_FBP images. The scores of high-contrast resolution of HR_eAIDR, NR_FBP, and HR_FBP images were 13, 8, and 13 cycles/cm, respectively, and the scores of low-contrast detectability were 5, 5, and 6 mm, respectively. Hence, an improvement in high-contrast resolution of signal more than 400 HU in the axial section can be achieved without increasing the radiation dose and decreasing low-contrast detectability with 10 HU using the HR mode and eAIDR.

A randomized clinical study on postoperative pain comparing between the supraglottic airway device and endotracheal tubing in transabdominal preperitoneal repair (TAPP)

BACKGROUND

Transabdominal preperitoneal (TAPP) repair is the most widely used laparoscopic technique for the treatment of inguinal hernia in Japan. Many studies have shown that in comparison with open hernia repair, laparoscopic repair results in less pain and a shorter convalescence. However, postoperative pain remains a concern. One possible cause of postoperative pain in the early postoperative phase is strain or cough on removal of the endotracheal tube. Use of a supraglottic airway (SGA) device helps to avoid such complaints. We evaluated postoperative pain after TAPP repair using the SGA for general anesthesia.

METHODS

We evaluated the postoperative pain in 146 patients with inguinal hernia repaired by TAPP in our hospital between May 2013 and May 2016. A total of 144 adult patients of American Society of Anesthesiologists physical status I and II who underwent needlescopic TAPP surgery were randomly allocated to one of two groups of 72 patients: group A (SGA), in which the patient's airway was secured with an appropriately sized I-gel, and group B (endotracheal tube), in which the airway was secured under laryngoscopy.

RESULTS

There was no significant difference between the groups regarding patient background, postoperative hospital stay, and operation time, and TAPP was performed safely in all cases. In the analysis of postoperative pain, the mean Numerical Rating Scale score of peak pain in group A was significantly less than that of group B (2.10 ± 2.05 vs 2.90 ± 2.65; p = 0.043). In group A, the percentage of patients who had an NRS score of 0 was 51.4% 30 min after surgery, 62.5% after 6 h and 68.1% at POD1, and compared to group B, the NRS scores were significantly higher at POD1 (p = 0.003), and the level of postoperative pain in group A tended to decrease earlier than that in group B.

CONCLUSIONS

The results of this study are the first to show that an SGA device can reduce postoperative pain after laparoscopic surgery.

RAD-Seq analysis of typical and minor Citrus accessions, including Bhutanese varieties

We analyzed the reduced-representation genome sequences of Citrus species by double-digest restriction site-associated DNA sequencing (ddRAD-Seq) using 44 accessions, including typical and minor accessions, such as Bhutanese varieties. The results of this analysis using typical accessions were consistent with previous reports that citron, papeda, pummelo, and mandarin are ancestral species, and that most Citrus species are derivatives or hybrids of these four species. Citrus varieties often reproduce asexually and heterozygosity is highly conserved within each variety. Because this approach could readily detect conservation of heterozygosity, it was able to discriminate citrus varieties such as satsuma mandarin from closely related species. Thus, this method provides an inexpensive way to protect citrus varieties from unintended introduction and to prevent the provision of incorrect nursery stocks to customers. One Citrus variety in Bhutan was morphologically similar to Mexican lime and was designated as Himalayan lime. The current analysis confirmed the previous proposition that Mexican lime is a hybrid between papeda and citron, and also suggested that Himalayan lime is a probable hybrid between mandarin and citron. In addition to Himalayan lime, current analysis suggested that several accessions were formed by previously undescribed combinations.

The Association Between MCT1 T1470A Polymorphism and Power-Oriented Athletic Performance

The purpose of this study was to investigate the effects of the MCT1 T1470A polymorphism (rs1049434) on power-oriented performance and lactate concentration during or after cycling sprints in Japanese wrestlers. Participants (199 wrestlers and 649 controls) were genotyped for the MCT1 T1470A genotype (rs1049434) using the TaqMan^® Assay. All wrestlers were international (n=77) or national (n=122) level athletes. Among them, 46 wrestlers performed 2 anaerobic performance tests, a 30-s Wingate Anaerobic test (WAnT) and a series of 10 maximal effort 10-s sprints on a cycle ergometer. Blood lactate levels were measured before, during, and after the tests. In the A-allele recessive model (AA vs. TA+TT), the frequency of the AA genotype was significantly higher in all wrestlers than in controls (p=0.037). Wrestlers with AA genotype had lower blood lactate concentrations than those with TA+TT genotype at 10 min after the WAnT and following the 5^th and the final set of repeated cycling sprints (p<0.05). The AA genotype of the MCT1 T1470A polymorphism is over-represented in wrestlers compared with controls and is associated with lower blood lactate concentrations after 30-s WAnT and during intermittent sprint tests in Japanese wrestlers.

Note: Novel diamond anvil cell for electrical measurements using boron-doped metallic diamond electrodes

A novel diamond anvil cell suitable for electrical transport measurements under high pressure has been developed. A boron-doped metallic diamond film was deposited as an electrode on a nano-polycrystalline diamond anvil using a microwave plasma-assisted chemical vapor deposition technique combined with electron beam lithography. The maximum pressure that can be achieved by this assembly is above 30 GPa. We report electrical transport measurements of Pb up to 8 GPa. The boron-doped metallic diamond electrodes showed no signs of degradation after repeated compression.

The 'when' and 'where' of semantic coding in the anterior temporal lobe: Temporal representational similarity analysis of electrocorticogram data

Electrocorticograms (ECoG) provide a unique opportunity to monitor neural activity directly at the cortical surface. Ten patients with subdural electrodes covering ventral and lateral anterior temporal regions (ATL) performed a picture naming task. Temporal representational similarity analysis (RSA) was used, for the first time, to compare spatio-temporal neural patterns from the ATL surface with pre-defined theoretical models. The results indicate that the neural activity in the ventral subregion of the ATL codes semantic representations from 250 msec after picture onset. The observed activation similarity was not related to the visual similarity of the pictures or the phonological similarity of their names. In keeping with convergent evidence for the importance of the ATL in semantic processing, these results provide the first direct evidence of semantic coding from the surface of the ventral ATL and its time-course.

[Verification of the protective effect of a testicular shield in postoperative radiotherapy for seminoma]

In postoperative radiotherapy for seminoma, control of the testicular absorbed dose is important, since exposure of the testis can lead to temporary or permanent infertility. In this case, instead of using a dog-leg-shaped field, treatment using a field focused near the aorta was provided in several disease stages of seminoma. However, the precise need for testicular shielding during treatment and dose of testis exposure was not clear. We examined these questions by measuring the testicular absorbed dose with and without a testicular shield using two clinical treatment plans and a phantom. The distance from the testis phantom and the lower end of the irradiation field was varied. Where the total dose for the tumor was 20 Gy, the testicular absorbed dose was below 0.1 Gy, the threshold dose for temporary infertility. At this dosage, the distance between the testis phantom and the edge of the irradiation field was 14.6 cm without the shield and 9.99 cm with the shield. Using a testes shield, it was thus possible to reduce the dose by 58.5%.

Expression of a Single-chain Antibody against Indole-3-acetic Acid inEscherichia coli

A hybridoma cell line that produces a monoclonal antibody specific for indole-3-acetic acid (IAA) was prepared. The DNA fragments coding the variable regions of the light and the heavy chains of the antibody were prepared by PCR using the cDNA of the antibody as a template. A chimera DNA for a single chain variable fragment (scFv) was constructed, and expressed in Escherichia coli. The scFv antibody expressed in E. coli as well as the original monoclonal antibody showed a specific binding to IAA.

[Verification of the dose from an iridium-192 ((192)Ir) sealed source absorbed by an implantable cardioverter defibrillator (ICD) during uterine intracavitary brachytherapy]

The purpose of this study was to verify the dose absorbed by an implantable cardioverter defibrillator (ICD) from an (192)Ir sealed source during uterine intracavitary brachytherapy, and to confirm its immunity to radiation effects. First, prior to treatment, the doses around the ICD position of an anthromorphic phantom were evaluated. Next, we also measured the dose at the ICD position using a fluorescent glass dosimeter and silicon diode dosimeter during the treatment of intracavitary brachytherapy of a patient implanted with an ICD. The results of the phantom study showed the dose percentage at the ICD location, 2 cm deep, to be 0.074% of the prescribed dose. The results of a treatment study similarly showed the dose, measured using a fluorescent glass dosimeter in the ICD position, to be 0.071% of the prescribed dose. During the application of the total prescribed dose, 30 Gy/5 fraction, the dose at the surface of the ICD position was estimated to be 21.2 mGy, well below the 1 Gy maximum recommended in the JASTRO guidelines. We regard dose verification and monitoring during treatment to be both necessary and useful in the treatment of individual cases.

Microsurgical medial fenestration with an ultrasonic bone curette for lumbar foraminal stenosis

BACKGROUND

Misdiagnosis and inadequate treatment of lumbar foraminal stenosis (LFS) are the most common causes of failed back surgery. Although several surgical procedures have been reported, the optimal surgical treatment remains controversial.

AIM

We describe our method of microsurgical medial fenestration using an ultrasonic bone curette (Sonopet, Stryker Corp., Kalamazoo, MI, USA) to treat patients with LFS and report our early results.

PATIENTS AND METHODS

We followed up 26 patients who had undergone microsurgical medial fenestration at least 1 year earlier. The patients were 15 men and 11 women with a mean age at surgery of 59.5 years; the mean follow-up period was 30.6 months. The affected nerve root was at L4 in 1 patient and at L5 in 25. Evaluation of our clinical results was based on the Japanese Orthopedic Association score.

RESULTS

There were no intraoperative surgery-related complications. After surgery, 1 patient had recurrence of L5 radiculopathy associated with iatrogenic spondylolysis. He was successfully treated with resection of the inferior articular process without fusion surgery; there was loss of disc height without obvious instability at the corresponding level. The Japanese Orthopedic Association scores showed significant improvement at 1 month after surgery and at final follow-up (p<0.001). No patient had spinal instability or malalignment postoperatively.

CONCLUSIONS

Microsurgical medial fenestration using Sonopet, a less-invasive surgical technique that does not result in spinal instability or malalignment, yielded excellent clinical outcomes.