Basic evaluation of a novel 4D target and human body phantom

Stereotactic body radiation therapy (SBRT) is usually verified with a dynamic phantom or solid phantom, but there is a demand for phantoms that can accurately simulate tumor dynamics within an individual that would allow customized validation in every patient. We developed a new 4D dynamic target phantom (multi-cell 4D phantom) that allows simulation of tumor movement in patients. The basic quality and dynamic reproducibility of this new phantom was verified in this investigation. The newly developed multi-cell 4D phantom comprises four main components: soft tissue, bones, lungs, and tumor (target). The phantom structure was based on computed tomography (CT) data of a male. In this study, we investigated the basic performance of a multi-cell 4D phantom. All the CT numbers of the phantom were very close to those of human data. The geometric maximum amplitudes were 4.57 mm in the lateral direction, 4.59 mm in the ventrodorsal direction, and 3.68 mm in the cranio-caudal direction. Geometric errors were 0.84, 0.58, and 0.40 mm, respectively. Movements of the abdominal surface were stable for 60 s. Repeated measurements show no actual differences in target movements between multiple measurements and indicated high reproducibility (r  >  0.97). End-to-end tests using Gafchromic film revealed a gamma pass rate of 98% or above (2 mm/3%). Although our phantom performed limited reproducibility in the movement of the patient tumor at present, a satisfactory level of precision was confirmed in general. This is a very promising device for use in the verification of radiation therapy for moving targets.

Molecular detection of fungal and bacterial DNA from pustules in patients with palmoplantar pustulosis: special focus on Malassezia species

BACKGROUND

Palmoplantar pustulosis (PPP) is a distinct, chronic skin disorder characterized by intraepidermal pustules on the palms and soles. It is hypothesized that microorganisms on the skin might induce the symptoms of PPP via inflammatory cell activation. However, the microbiota has not been studied in detail because of the assumption that the pustules in PPP are sterile.

AIM

To elucidate the role of microorganisms in pathogenesis of PPP.

METHODS

PCR analysis was performed of microbial DNA fragments in the pustules of patients with PPP. The sequence of the D1/D2 LSU 26s rRNA gene and that of the 16S rRNA gene was used for fungal and bacterial DNA detection, respectively.

RESULTS

In total, 71 samples were carefully collected from the pustules of patients with PPP. Fungal DNA bands were detected in 68 samples, and fungi including Malassezia spp. were identified in 30 of 71 samples (42.3%). Malassezia restricta was the most frequently encountered fungus (14/71; 19.7%). However, bacterial DNA was not detected by the methods used. Furthermore, identical fungal DNA was not detected in the outer lid of the pustules, suggesting that the fungi detected within the pustule did not derive from contamination via the skin surface.

CONCLUSIONS

In the present study, we demonstrated for the first time that certain pustules in patients with PPP contain fungal DNA fragments, especially those of Malassezia spp. Our findings provide new insights on the role of skin microbiota in the pathogenesis of PPP.

DOSE-RATE AND CELL-KILLING SENSITIVITY OF HIGH-LINEAR ENERGY TRANSFER ION BEAM

It is believed that the dose-rate of radiation will have an influence on cell sensitivity. The dose-rate effects on cell survival can be expressed by the change of the β term in the linear quadratic model. The value at a high-dose-rate decreases below 60 Gy/h and reaches zero at 0.2 Gy/h or less for photons. However, the effect for a high-LET ion-beam is not well known. At HIMAC, cells were exposed to 70 keV/μm carbon-ion beams at different dose-rates between 0.5 and 600 Gy/h at room temperature. The β values for all survival curves show no significant differences among the dose-rates tested for HSG, V79 and CHO cells. Changing the ion-beam dose-rate had no effect on cell survival. This suggests that high-LET particle beams, such as galactic cosmic rays, may not exhibit a dose-rate effect on cell survival. Low-dose-rate radiation showed an effect similar to high-dose-rate radiation.

Development and evaluation of a cervical cancer screening system in Cambodia: A collaborative project of the Cambodian Society of Gynecology and Obstetrics and Japan Society of Obstetrics and Gynecology

Aim

In Cambodia, the Japan Society of Obstetrics and Gynecology and the Cambodian Society of Gynecology and Obstetrics have an on‐going project, started in 2015, for cervical cancer prevention and treatment. The project, currently aimed at factory workers, includes a women’s health education program that leads into cervical cancer prevention by establishment of a system for early detection and treatment. It begins by health education, screening for human papillomavirus (HPV), followed by colposcopy and quicker treatment of earlier precursor lesions.

Methods

Rates for participant screening, HPV test positivity, cervical intraepithelial neoplasia (CIN) detection and distribution of HPV types were compared between two screening programs, factory‐based and hospital‐based. Some HPV test samples were divided into two, one of which was sent to Japan for a quality‐control check of the Cambodian testing.

Results

The factory‐based participant screening rate was 19% (128/681). HPV was detected more frequently in the factory‐based program participants (12%) than in the hospital‐based program participants (5%). Unfortunately, however, the rate of receiving proper secondary colposcopy screening among the HPV‐positive females was significantly higher in the hospital‐based program (94%) than the factory‐based program (40%) (P < 0.001). The Cambodian laboratory HPV testing accuracy was 92.6%. HPV types demonstrated no significant difference between the two prevention programs.

Conclusion

We could successfully introduce HPV‐based screening, starting from health education. However, low rate of screening, especially secondary screening for HPV positive factory workers was identified. Also, HPV testing could be further improved for accuracy through close monitoring.

Abstract P6-01-02: Machine learning-based structural analysis and oxygen saturation measurement of tumor-associated vessels in breast cancer using a photoacoustic tomography system

Introduction

Breast cancer induces angiogenesis, one of the primary factors responsible for tumor progression. Therefore, the ability to visualize angiogenesis at a higher resolution is crucial. Photoacoustic tomography is a noninvasive method of visualizing angiogenesis involving light absorption and ultrasonic wave emission. If the irradiation light wavelength is adjusted for hemoglobin, vascular imaging is possible. Furthermore, using two wavelengths for oxidized and reduced hemoglobin, “S-factor,” can be calculated, which nearly corresponds to oxygen saturation. Therefore, photoacoustic imaging allows the assessment of breast lesions from vascular structural and functional viewpoints.

Objectives

This study aimed to demonstrate the possible utility of photoacoustic tomography for clinical application focusing on the morphologic features and oxygen saturation status of breast tumor-related vessels.

Methods

For the morphological analysis, we applied a machine learning-based method for automatic vessel extraction, and for the functional analysis we evaluated hemoglobin oxygen saturation calculating signals obtained at two wavelengths. In our system, a 3D ultrasound image was simultaneously acquired as a volume image of a tumor, which helped analyze the positional relationship between the vessels and the tumor.

Results

On morphological analysis, the fine structure of tumor-related vessels was rendered in high resolution. In our system, the blood vessels branched toward the tumor 2-3 more times more frequently than observed on contrast-enhanced MRI, illustrating a finer level of blood vessels near the tumor on our system than on MRI. Next, we analyzed the six morphologic features of vessels (radius, volume, curvature, contraction, maximum angle and vessel branch number) that are associated with the pathologic condition in neuroscience. We determined that the feature distribution of vessels located close to the tumor differed from that located away from the tumor. For example, vessels near the tumor had higher curvature, which means they are more tortuous than healthy vessels. The difference in the distribution of all six features was statistically significant on the Kolmogorov-Smirnov test.

On functional analysis, S-factor measurement of the healthy human breast demonstrated clearly demarcated arteries and veins. The S-factor of any artery was nearly 100%, while that of the veins inside the breast cancer tended to be a little higher (approximately 5%) compared to that in the healthy part. This tendency of veins was not recognized in benign tumors. This could show arteriovenous shunt in cancer microenvironment. We found low saturation signals emerging in the tumor tissue following bevacizumab-containing chemotherapy, indicating the possibility that our system reveals microenvironment changes.

Discussion

If our system can identify the structure or oxygen saturation characteristics unique to tumor-associated vasculature, it could contribute to the improved accuracy of breast cancer diagnosis and allow the observation of tumor vessel normalization because of the drug treatment. An earlier grasp of the therapeutic effect could lead to the provision of individualized medicine.

Citation Format: Matsumoto Y, Gu L, Bise R, Asao Y, Sekiguchi H, Yoshikawa A, Ishii T, Takada M, Kataoka M, Sakurai T, Yagi T, Sato I, Togashi K, Shiina T, Toi M. Machine learning-based structural analysis and oxygen saturation measurement of tumor-associated vessels in breast cancer using a photoacoustic tomography system [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-01-02.

Homogeneous reduced moment in a gapful scalar chiral kagome antiferromagnet

We present a quantitative experimental investigation of the scalar chiral magnetic order with in Nd3Sb3Mg2O14. Static magnetization reveals a net ferromagnetic ground state, and inelastic neutron scattering from the hyperfine coupled nuclear spin reveals a local ordered moment of 1.76(6) μ B , just 61(2)% of the saturated moment size. The experiments exclude static disorder as the source of the reduced moment. A 38(1) μ eV gap in the magnetic excitation spectrum inferred from heat capacity rules out thermal fluctuations and suggests a multipolar explanation for the moment reduction. We compare Nd3Sb3Mg2O14 to Nd pyrochlores and show that Nd2Zr2O7 is in a spin fragmented state using nuclear Schottky heat capacity.

Terminal Ileac Ulcers Mimicked Post-transplantation Lymphoproliferative Disorder in a Heart Recipient Treated With Everolimus: A Case Report

Post-transplant lymphoproliferative disorder (PTLD) is a well-recognized and potentially fatal complication of cardiac transplantation that commonly involves the gastrointestinal tract. Herein, we report a case of life-threatening gastrointestinal bleeding from recurrent terminal ileac ulcers mimicking PTLD in a heart recipient treated with everolimus (EVL). A 40-year-old man underwent heart transplantation for dilated cardiomyopathy 3 years prior to the current admission and was treated with tacrolimus and EVL. He was admitted to a local hospital because of fever, abdominal pain, and diarrhea. His symptoms persisted and, 3 weeks later, hematochezia occurred; thus, he was transferred to our hospital. As computed tomography and ¹⁸F-fluorodeoxyglucose positron emission tomography showed bowel-wall thickening of the terminal ileum, gastrointestinal PTLD was initially suspected. However, although colonoscopy- performed after switching EVL to mycophenolate mofetil (MMF)-showed terminal ileac ulcers, the histologic examination revealed no findings corresponding to PTLD. As EVL may delay ulcer healing, MMF was maintained for 3 months. After repeated colonoscopy showed ulcer healing, MMF was switched back to EVL for cardiac allograft vasculopathy prevention. Three weeks later, he was emergently admitted to a local hospital for life-threatening gastrointestinal bleeding from a recurrent terminal ileal ulcer, which required hemostatic forceps hemostasis. As EVL is suspected to be associated with recurrent ileal ulcers, EVL was again switched back to MMF. The ileal ulcers resolved, without recurrence in 3 months of clinical follow-up. This case demonstrates that cases of life-threatening gastrointestinal bleeding from recurrent terminal ileac ulcers can mimic PTLD in a heart recipient treated with EVL.

Progressive reduction of serum complement levels: a risk factor for relapse in patients with hypocomplementemia in systemic lupus erythematosus

Objective

Serologically active clinically quiescent (SACQ)-SLE is a subtype of systemic lupus erythematosus (SLE); most SACQ-SLE patients relapse. Although complement and/or anti-dsDNA level fluctuations during SACQ status are reportedly not useful for predicting relapse, they might be useful in specific clinical settings. We aimed to assess the correlation between future relapse and progressive reductions in serum complement levels following remission in patients with hypocomplementemia .

Methods

We retrospectively reviewed patients aged ≥15 years who were treated with ≥20 mg/day of prednisolone for remission induction. After achieving remission, the patients treated with prednisolone tapered to ≤15 mg/day without relapse and followed by hypocomplementemia (first hypocomplementemia point) were analyzed. The primary outcome was the relapse during the first 24 months.

Results

Seventy-six patients were enrolled; 31 (40.8%) relapsed. A ≥10% reduction after the first hypocomplementemia point in serum C3, C4, and CH50 levels was found in 10, 21, and 16 patients, respectively. Hazard ratios (95% confidence intervals) for relapse were 2.32 (0.92–5.12) for serum C3 levels and 2.46 (1.18–5.01) for serum C4 levels. Progressive reductions in serum C3 and C4 levels had relatively high specificity (93.3% and 82.2%) but limited sensitivity (22.6% and 41.9%) for predicting relapse. However, simultaneous progressive reduction in C3 levels and increase in anti-dsDNA antibody levels had the highest specificity (97.8%), and simultaneous progressive reduction in C4 levels or increase in anti-dsDNA antibody levels had the highest sensitivity (71.0%).

Conclusion

Simultaneous progressive reductions in complement levels and increases in anti-dsDNA antibody levels may indicate future relapse SACQ-SLE patients.