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The irradiation field of boron neutron capture therapy (BNCT) consists of multiple dose components including thermal, epithermal and fast neutron, and gamma. The objective of this work was to establish a methodology of dosimetric quality assurance (QA), using the most standard and reliable measurement methods, and to determine tolerance level for each QA measurement for a commercially available accelerator-based BNCT system. In order to establish a system of dosimetric QA suitable for BNCT, the following steps were taken. First, standard measurement points based on tissue-administered doses in BNCT for brain tumors were defined, and clinical tolerances of dosimetric QA measurements were derived from the contribution to total tissue relative biological effectiveness factor-weighted dose for each dose component. Next, a QA program was proposed based on TG-142 and TG-198, and confirmed that it could be assessed whether constancy of each dose component was assured within the limits of tolerances or not by measurements of the proposed QA program. Finally, the validity of the BNCT QA program as an evaluation system was confirmed in a demonstration experiment for long-term measurement over 1 year. These results offer an easy, reliable QA method that is clinically applicable with dosimetric validity for the mixed irradiation field of accelerator-based BNCT.

Purpose To conduct a ≥15-year follow-up assessment of the visual field (VF) in normal-tension glaucoma (NTG) patients receiving medical therapy and to identify risk factors for VF progression. Design A retrospective clinical study. Methods Medical records of 78 eyes of 78 NTG patients monitored for ≥15 years were reviewed. VF progression was defined by a mean deviation (MD) deteriorated twice by 3.00 dB from baseline (MD criterion) and an annual decrease in the MD slope exceeding −0.5 dB/year (MD slope criterion). Logistic regression analysis was employed to identify risk factors for VF progression. Results The mean follow-up period was 18.3 years. The average intraocular pressure (IOP) before treatment was 15.1 ±1.9 mmHg and the average treated IOP was 13.5 ±1.5 mmHg with 2.0 medications. Forty-two eyes (53.8%) showed VF progression using the MD criterion and 15 eyes (19.2%) showed a negative MD slope less than −0.5 dB/year. Disc hemorrhage (DH) was observed in 30 eyes (38.5%). The mean VF progression rate was −0.38 ±0.30 dB/year in the DH group and −0.24 ±0.28 dB/year in the non-DH group ( P  = 0.012). Multiple logistic regression analysis identified DH [relative risk (RR) 4.28; P  = 0.028] as a risk factor for VF progression using the MD criterion. DH (RR 8.77; P  = 0.007) and IOP fluctuation during follow-up (RR 5.03; P  = 0.048) were detected as risk factors using the MD slope criterion. Conclusions DH and IOP fluctuation were associated with VF progression in NTG during long-term therapy.

The dosimetric effect of set-up error in boron neutron capture therapy (BNCT) for head and neck cancer remains unclear. In this study, we analyzed the tendency of dose error by treatment location when simulating the set-up error of patients. We also determined the tolerance level of the set-up error in BNCT for head and neck cancer. As a method, the distal direction was shifted with an interval of 2.5 mm, from 0.0 mm to +20.0 mm and compared with the dose at the reference position. Similarly, the horizontal direction and vertical direction were shifted, with an interval of 5.0 mm, from −20.0 mm to +20.0 mm. In addition, cases with 3.0 mm and 5.0 mm simultaneous shifts in all directions were analyzed as the worst-case scenario. The dose metrics of the minimum dose of the tumor and the maximum dose of the mucosa were evaluated. From unidirectional set-up error analysis, in most cases, the set-up errors with dose errors within ±5% were Δdistal < +2.5 mm, Δhorizontal < ±5.0 mm and Δvertical < ±5.0 mm. In the simulation of 3.0 mm shifts in all directions, the errors in the minimum tumor dose and maximum mucosal dose were −3.6% ±1.4% (range, −5.4% to −0.6%) and 2% ±1.4% (range, 0.4% to 4.5%), respectively. From these results, if the set-up error was within ±3.0 mm in each direction, the dose errors of the tumor and mucosa could be suppressed within approximately ±5%, which is suggested as a tolerance level.

Purpose This study aimed to evaluate the dosimetric properties of a newly developed thermoluminescent sheet‐type dosimeter (TLD‐sheet) for clinical proton beams. Materials and Methods The TLD‐sheet is composed mainly of manganese doped lithium triborate, with a physical size and thickness of 150 mm × 150 mm and 0.15 mm respectively. It is flexible and can be cut freely for usage. The TLD‐sheet has an effective atomic number of 7.3 and tissue‐equivalent properties. We tested the reproducibility, fading effect, dose linearity, homogeneity, energy dependence, and water equivalent thickness (WET) of the TLD‐sheet for clinical proton beams. We conducted tests with both unmodulated and modulated proton beams at energies of 150 and 210 MeV. Results The measurement reproducibility was within 4%, which included the inhomogeneity of the TLD‐sheet. The fading rates were approximately 20% and 30% after 2 and 7 days respectively. The TLD‐sheet showed notable energy dependence in the Bragg peak and distal end of the spread‐out Bragg peak regions. However, the dose–response characteristics of the TLD‐sheet remained linear up to a physical dose of 10 Gy in this study. This linearity was highly superior to those of commonly used radiochromic film. The thin WET of the TLD‐sheet had little effect on the range. Conclusion Although notable energy dependences were observed in Bragg peak region, the response characteristics examined in this study, such as reproducibility, fading effects, dose linearity, dose homogeneity and WET, showed that the TLD‐sheet can be a useful and effective dosimetry tool. With its flexible and reusable characteristics, it may also be an excellent in vivo skin dosimetry tool for proton therapy.

Purpose To determine whether significant correlations existed between the morphological and functional parameters of the macular region of eyes with open-angle glaucoma (OAG). Methods Forty eyes of 40 OAG patients were studied. The morphological parameters were obtained by optical coherence tomography (OCT), and the functional parameters were acquired by automated Humphrey Field Analyzer (HFA) and multifocal electroretinograms (mfERGs). All of the tests were performed within 6 months of each other. The retinal thickness was determined by OCT in the nine Early Treatment of Diabetic Retinopathy Study (ETDRS) sectors of the macula, the fovea, and the four quadrants of the inner and an outer ring. The amplitudes of the second-order kernel responses of the mfERGs in the central 5° including the amplitude ratio of the nasal to temporal hemispheres ( N / T amplitude ratio) were analyzed. The total mean deviation of the HFA corresponding to each OCT region was measured. The correlation between the different parameters was determined by coefficients of correlation and linear regression analyses. Results The N / T amplitude ratio of the second-order kernel responses of the mfERGs was significantly correlated with the retinal thickness in the inferior quadrant ( r  = −0.44; P  = 0.004). There was a significant correlation between the N / T amplitude ratio and the threshold in the superior quadrant measured by the HFA Central 10-2 program ( r  = −0.40; P  = 0.011) and also between the N / T amplitude ratio and the total deviation in the superior quadrant ( r  = −0.40; P  = 0.010). There were significant correlations between the inferior retinal thickness and the average threshold and the TD in superior ( r  = 0.70, P  < 0.001; r  = 0.692, P  < 0.001, respectively), nasal ( r  = 0.53, P  < 0.001; r  = 0.53, P  < 0.001, respectively), and temporal ( r  = 0.46, P  = 0.003; r  = 0.44, P  = 0.004, respectively) quadrants. Conclusions Functional glaucomatous changes determined by mfERGs and perimetry are significantly correlated with the morphological changes determined by OCT.

We report a rare case of endogenous endophthalmitis caused by Streptococcus equisimilis. A 74-year-old woman with endocarditis developed endogenous endophthalmitis. The patient underwent emergency mitral valvuloplasty, and intravitreal and subconjunctival injections of vancomycin and meropenem. After the surgery, she was treated with topical antibiotics, ointment, intravenous gentamicin and intravenous penicillin G potassium. The causative organism was identified as S. equisimilis. S. equisimilis should be considered as a pathogen that can cause severe endogenous endophthalmitis.

Purpose To analyze the respiratory‐induced motion trajectories of each liver segment for hepatocellular carcinoma (HCC) to derive a more accurate internal margin and optimize treatment protocol selection. Materials and Methods Ten‐phase‐gated four‐dimensional computed tomography (4DCT) scans of 14 patients with HCC were analyzed. For each patient, eight representative regions of interest (ROI) were delineated on each liver segment in all 10 phases. The coordinates of the center of gravity of each ROI were obtained for each phase, and then the respiratory motion in the left–right (LR), anteroposterior (AP), and craniocaudal (CC) directions was analyzed. Two sets of motion in each direction were also compared in terms of only two extreme phases and all 10 phases. Results Motion of less than 5 mm was detected in 12 (86%) and 10 patients (71%) in the LR and AP directions, respectively, while none in the CC direction. Motion was largest in the CC direction with a maximal value of 19.5 mm, with significant differences between liver segment 7 (S7) and other segments: S1 (p < 0.036), S2 (p < 0.041), S3 (p < 0.016), S4 (p < 0.041), and S5 (p < 0.027). Of the 112 segments, hysteresis >1 mm was observed in 4 (4%), 2 (2%), and 15 (13%) in the LR, AP, and CC directions, respectively, with a maximal value of 5.0 mm in the CC direction. Conclusion A significant amount of respiratory motion was detected in the CC direction, especially in S7, and S8. Despite the small effect of hysteresis, it can be observed specifically in the right lobe. Therefore, caution is required when using 4DCT to determine IM using only end‐inspiration and end‐expiration. Understanding the respiratory motion in individual liver segments can be helpful when selecting an appropriate treatment protocol.

Purpose To investigate the dosimetric effect of six degrees of freedom (6DoF) couch top with rotational corrections in proton therapy (PT). Methods The water equivalent thickness (WET) was measured using a proton beam with a 6DoF couch top and patient immobilization base plate (PIBP) placed in front of a motorized water phantom. The accuracy verification was performed with the beam axis set perpendicular to the 6DoF couch top and tilted in 10° steps from 10° to 30°. Up to 3° rotational correction may be added during the actual treatment to correct the rotational setup error on our system. The measured and calculated values using the treatment planning system were compared. Additionally, the effect of the 3° difference was evaluated using actual measurements concerning each angle on the proton beam range. Results The WET of the 6DoF couch top and PIBP were 8.5 ± 0.1 mm and 6.8 ± 0.1 mm, respectively. The calculation and the actual measurement at each angle agreed within 0.2 mm at the maximum. A maximum difference of approximately 0.6 mm was confirmed when tilted at 3° following 30° with the 6DoF couch top plus PIBP. Conclusions The dosimetric effect of the 6DoF couch top with rotational corrections in PT differs depending on the incidence angle on the couch top, and it increased with the increased oblique angle of incidence. However, the effect on the range was as small as 0.6 mm at the maximum. The amount of rotational correction, the angle of incidence of the beam, and the effect of rotational corrections on the proton beam range may differ depending on the structure of the couch top. Therefore, sufficient prior confirmation, and subsequent periodical quality assurance management are important.

We report a case of infectious endophthalmitis that developed after the third intravitreal injection of bevacizumab. The endophthalmitis was caused by Staphylococcus epidermidis. Observational case series. This was a case of a 77-year-old man who had received three intravitreal injections of bevacizumab and developed infectious endophthalmitis. Polymerase chain reaction of an aqueous humor sample showed that the endophthalmitis was caused by S. epidermidis. The patient received intravitreal ceftazidime and vancomycin, and subconjunctival injection of vancomycin. After the intravitreal injections he was treated with topical levofloxacin and cefmenoxime hydrochloride, and intravenous cefpirome. Subsequently, the ocular inflammation gradually decreased and his visual acuity remained at 30/200. Our findings indicate that endophthalmitis can develop after intravitreal bevacizumab injections. Polymerase chain reaction is useful for differentiation from sterile endophthalmitis.