Adjuvant Brachytherapy with Ruthenium-106 to Reduce the Risk of Recurrence of Conjunctival Melanoma after Excision.

Introduction: Local recurrence of conjunctival melanoma (CM) is common after excision. Local radiotherapy is an effective adjuvant treatment option, and brachytherapy with ruthenium-106 (106Ru) is one such option. Thus, herein, we aimed to describe our experience with and the clinical results of post-excision adjuvant 106Ru plaque brachytherapy in patients with CM. Methods: Nineteen patients (8 men and 11 women) received adjuvant brachytherapy with a 106Ru plaque after tumor excision. The mean adjuvant dose administered was 109 Gy (range, 80-134 Gy), and a depth of only 2.2 mm was targeted because the tumor had been excised. A full ophthalmological examination including visual acuity testing, slit-lamp examination, and indirect ophthalmoscopy was performed before therapy and at every postoperative follow-up. The mean follow-up period was 62 months (range, 2-144 months). Results: Three patients developed a recurrence in a nontreated area, at either the conjunctiva bulbi or the conjunctiva tarsi. None of the patients developed a recurrence in the treated area. The local control rate was 84% (16/19). Conclusion: 106Ru plaque brachytherapy is an effective adjuvant treatment to minimize the risk of local recurrence after excision of a CM. Patients have to be followed up regularly and carefully for the early detection of recurrence.

Ruthenium-106 Plaque Brachytherapy for Circumscribed Choroidal Hemangioma: A Case Series and Review of Literature.

Introduction: We aim to report the anatomical and functional outcomes of ruthenium-106 brachytherapy in the management of circumscribed choroidal hemangiomas (CCH). Methods: This is a single-center, retrospective case series including patients with unilateral symptomatic CCH treated with ruthenium-106 brachytherapy at the Cairo University Ocular Oncology Service. Patient records were analyzed for patients' demographics, best corrected visual acuity (BCVA), tumor dimensions (thickness and largest base diameter), foveal subretinal fluid, radiation-related complications, and recurrence. Results: Seven patients were included in the study (including 6 males) with a mean age of 39.3 ± 15.4 years; ruthenium-106 plaque was used to deliver 50 Gray to the tumor apex. After a mean follow-up duration of 12.5 months, all patients had significant improvement in BCVA after treatment, mean tumor height decreased significantly from 4.76 ± 1.76 mm to 1.70 ± 1.2 mm (p value 0.01). The largest tumor base diameter also decreased significantly from 9.13 ± 2.68 mm to 4.65 ± 3.75 mm (p value 0.05). Subretinal fluid and exudative retinal detachment resolved in all patients, and no significant radiation-related complications were observed in any patient. None of the patients needed any further treatment or experienced recurrence within the follow-up period. Conclusion: Ruthenium-106 brachytherapy is an effective tool in the management of symptomatic CCH with a good visual prognosis and safety profile.

Ruthenium-106 (106Ru) plaque brachytherapy for treatment of circumscribed choroidal hemangioma.

PURPOSE: To describe the clinical and imaging features of circumscribed choroidal hemangiomas (CCH) and their treatment outcomes with Ruthenium-106 (106Ru) plaque brachytherapy. METHODS: Retrospective study of 24 patients (24 eyes) diagnosed with CCH and treated with 106Ru plaque between 2017 and 2022. Analysis included pre- and post-treatment clinical and imaging features such as tumor regression, reduction in height, subretinal fluid (SRF) resolution, and change in best-corrected visual acuity (BCVA). RESULTS: The mean age at presentation was 36 years (range, 16-57). The most common tumor location was the temporal quadrant (n = 19) with macular involvement (n = 13). Associated features were macular SRF (n = 22) and inferior exudative retinal detachment (n = 10). Nineteen of the 24 patients underwent primary treatment, whereas 5 patients underwent plaque as a salvage treatment. The mean tumor apex dose was 40 Gy. At a median follow-up of 7.5 months (range 3-65 months), 18 eyes showed complete regression, whereas 6 eyes showed partial regression. The mean height decreased from 4.8 (SD 1.28) mm at presentation to 2.5 (SD 1.63) mm. Median BCVA improved from logMAR 1.2 (IQR 0.4-2) at baseline to logMAR 1.05 (IQR 0.1-1.95) (p = 0.4). Complete resolution of the macula and tumor SRF was observed in 15 (68%) and 13 (57%) eyes, respectively. The radiation-related complications observed were radiation maculopathy (4 eyes), retinopathy (1 eye), and vitreous hemorrhage (1 eye). CONCLUSION: Ruthenium-106 plaque brachytherapy is effective for CCH (> 3 mm height) as a primary and salvage treatment for tumors unresponsive to other modalities.

Measurements regarding a combined therapy concept for ophthalmic tumors consisting of brachytherapy and x-rays.

Objective.We present a novel concept to treat ophthalmic tumors which combines brachytherapy and low-energy x-ray therapy. Brachytherapy with106Ru applicators is inadequate for intraocular tumors with a height of 7 mm or more. This results from a steep dose gradient, and it is unfeasible to deliver the required dose at the tumor apex without exceeding the maximum tolerable sclera dose of usually 1000 Gy to 1500 Gy. Other modalities, such as irradiation with charged particles, may be individually contraindicated. A dose boost at the apex provided by a superficial x-ray therapy unit, performed simultaneously with the brachytherapy, results in a more homogeneous dose profile than brachytherapy alone. This avoids damage to organs at risk. The applicator may also serve as a beam stop for x-rays passing through the target volume, which reduces healthy tissue dosage. This study aims to investigate the suitability of the applicator to serve as a beam stop for the x-rays.Approach.A phantom with three detector types comprising a soft x-ray ionization chamber, radiochromic films, and a self-made scintillation detector was constructed to perform dosimetry. Measurements were performed using a conventional x-ray unit for superficial therapy to investigate the uncertainties of the phantom and the ability of the applicator to absorb x-rays. The manufacturer provided a dummy plaque to obtain x-ray dose profiles without noise from106Ru decays.Results.The phantom is generally feasible to obtain dose profiles with three different detector types. The interaction of x-rays with the silver of the applicator leads to an increased dose rate in front of the applicator. The dose rate of the x-rays is reduced by up to 90% behind a106Ru applicator. Therefore, a106Ru applicator can be used as a beam stop in combined x-ray and brachytherapy treatment.

Brachytherapy in the prevention of recurrence of conjunctival melanoma : Results of a case report in a University Hospital in Valladolid, Spain.

AIM: Describe the results of brachytherapy in the prevention of recurrences in conjunctival melanoma (CM) and describe a dosimetric protocol. METHODS: Retrospective and descriptive case report. Eleven consecutive patients with a confirmed histopathological diagnosis of CM treated with brachytherapy between 1992 and 2023 were reviewed. Demographic, clinical, and dosimetric characteristics as well as recurrences were recorded. Quantitative variables were represented by the mean, median, and standard deviation, and qualitative variables by frequency of distribution. RESULTS: Of a total of 27 patients diagnosed with CM, 11 who were treated with brachytherapy were included in the study (7 female; mean age at time of treatment: 59.4 years). Mean follow-up was 58.82 months (range 11-141 months). Of a total of 11 patients, 8 were treated with ruthenium-106 and 3 with iodine-125. Brachytherapy was performed in 6 patients as adjuvant therapy after biopsy-proven CM on histopathology and in the other 5 patients after recurrence. The mean dose was 85 Gy in all cases. Recurrences outside of the previously irradiated area were observed in 3 patients, metastases were diagnosed in 2 patients, and one case of an ocular adverse event was reported. CONCLUSION: Brachytherapy is an adjuvant treatment option in invasive conjunctival melanoma. In our case report, only one patient had an adverse effect. However, this topic requires further research. Furthermore, each case is unique and should be evaluated by experts in a multidisciplinary approach involving ophthalmologists, radiation oncologists, and physicists.

Hydrogen nanobubbles: A novel approach toward radio-sensitization agents.

BACKGROUND: Ocular melanoma is a rare kind of eye malignancy that threatens the patient's eyesight. Radiotherapy and surgical removal are the most commonly used therapeutic modalities, and nanomedicine has lately entered this field. Brachytherapy using Ruthenium-106 (106 Ru) ophthalmic plaques has been used for decades to treat ocular melanoma, with the applicator placed on the patient's eyes until the prescribed dose reaches the tumor apex. PURPOSE: To investigate the efficiency of hydrogen nanobubbles (H2 -NBs) employment during intraocular melanoma brachytherapy using a 106 Ru electron emitter plaque. METHODS: The Monte Carlo (MC) simulation and experimental investigation using a 3D-designed phantom and thermoluminescence dosimetry (TLD) were employed. Various concentrations of H2 -NBs with a diameter of 100 nm were simulated inside tumor tissue. The results were presented as deposited energy and dose enhancement factor (DEF). An equivalent Resin phantom of the human eyeball was made using AutoCAD and 3D-Printer technologies. The glass-bead TLDs dosimeter were employed and placed inside the phantom. RESULTS: Using a 1% concentration of H2 -NBs, a DEF of 93% and 98% were achieved at the tumor apex of 10 mm from the experimental setup and MC simulation, respectively. For simulated concentrations of 0.1%, 0.3%, 0.5%, 1%, and 4% H2 -NBs, a maximum dose enhancement of 154%, 174%, 188%, 200%, and 300% were achieved, respectively, and a dose reduction was seen at about 3 mm from the plaque surface. CONCLUSION: H2 -NBs can be used as an absorbed dose enhancer in 106 Ru eye brachytherapy because of their unique physical characteristics. Reducing plaque implantation time on the patient's eye, reducing sclera absorbed dose, and decreasing the risk of patients' healthy organs irradiation are reported as some of the potential benefits of using H2-NBs.

Melphalan intra-arterial chemotherapy for choroidal melanoma chemoreduction.

BACKGROUND: Intra-arterial chemotherapy (IAC) has been used to treat multiple cancers including liver metastasis from uveal and cutaneous melanoma but not as primary tumor treatment. We report the compassionate use of chemoreduction with intra-arterial melphalan before ruthenium brachytherapy to salvage an eye with choroidal melanoma. CASE PRESENTATION: A 61-year-old female patient complained of decreased vision and central-temporal scotoma in OS (left eye) for 1 month. Visual acuity was 20/20 in right eye (OD) and 20/125 OS. Anterior segment examination and intraocular pressure were unremarkable in both eyes, as was fundus examination of the OD. Fundus examination of OS revealed a brown, solid tumor partially obscuring the temporal optic disc margin and extending to the equatorial fundus midzone. Serous retinal detachment was present over the lesion and around it. Ultrasonography revealed a solid choroidal tumor with a largest basal diameter (LBD) of 13.0 mm and thickness of 10.4 mm. The tumor presented acoustic hollowness and a superimposing retinal detachment. After metastatic screening was negative, the patient underwent intra-arterial chemotherapy with melphalan. Three weeks later, her visual acuity was 20/200 and there was noticeable tumor regression to 11.9 mm (LBD) by 7.9 mm (thickness) allowing brachytherapy to be performed. Ten weeks after brachytherapy (13 weeks after IAC), visual acuity was HM due to biopsy-related vitreous hemorrhage (VH). Tumor dimensions were 9.9 (LBD) mm and 6.5 mm (thickness) and PPV was performed to remove VH. Six weeks after PPV (20 weeks after IAC), her visual acuity was 20/200 and further reduction of tumor dimensions was observed: largest basal diameter was 8.9 mm and thickness was 4.9 mm. CONCLUSION: This case illustrates the feasibility of combining induction IAC prior to ruthenium brachytherapy for large choroidal melanoma. More studies are warranted to confirm these early preliminary findings.

Palladium-103 plaque brachytherapy for retinoblastoma: Long term follow up.

Purpose: Radiation has been used in the treatment of retinoblastoma. Herein, we present the novel use of palladium-103 plaque brachytherapy as primary treatment. Observation: An 8-year-old asymptomatic girl presented was found to have a solitary peripheral retinoblastoma in her right eye. She was treated with primary palladium-103 plaque brachytherapy (47.4 Gray over 5 consecutive days). A secondary, vitreous hemorrhage noted 46 months after irradiation was successfully controlled by laser tumor-demarcation. With 19-years follow up, there has been no clinical scleropathy, or local tumor recurrence. The eye yields 20/20 vision and there has been no systemic metastasis. Conclusion and importance: Palladium-103 plaque brachytherapy successfully controlled retinoblastoma, while preserving the globe, vision, and life.

Short-term changes of cornea and tear film after ruthenium-106 plaque therapy for intraocular tumors.

PURPOSE: Plaque therapy is a well-recognized treatment for intraocular tumors. In current study, we aimed to prospectively investigate the short-term effects of ruthenium 106 (Ru-106) plaque therapy on the cornea and ocular surface parameters. METHODS: Twenty-five patients diagnosed with choroidal melanoma which undergone Ru-106 plaque therapy from 2016 to 2018 were included. Tear osmolarity, tear film break-up time, Schirmer test I, fluorescein dye staining based on Oxford staining method; Ocular Surface Disease Index (OSDI) questionnaire and corneal specular microscopy were performed. These tests were assessed preoperatively and then 3 months postoperatively. RESULTS: The mean (±SD) age of subjects was 48.52 ± 15.18 years. The patients were followed for a mean(±SD) period of 3.64 ± 2.40 months. Total mean (+SD) delivered radiation dose to the tumor apex and total received radiation by the sclera was 83.20 ± 26.31 and 640.65 ± 472.69 Gray (Gy), respectively. In longitudinal analysis, OSDI score and Oxford staining score increased significantly (P = 0.002 for both variables) and the prevalence of dry eye disease (DED) increased from 20% preoperatively to 72% at 3 months postoperatively (P = 0.001).The changes in the all specular microscopy parameters were statistically nonsignificant (all P values > 0.05). CONCLUSION: There is a considerable increase in the rate of DED following plaque therapy for the treatment of choroidal melanoma in short-term follow-up. The OSDI questionnaire and fluorescein staining test are valuable tools for early detection of DED postoperatively.

Evaluation of radiation maculopathy after treatment of choroidal melanoma with ruthenium-106 using optical coherence tomography angiography.

BACKGROUND: To assess the impact of brachytherapy on macular microvasculature utilizing optical coherence tomography angiography (OCTA) in treated choroidal melanoma. METHODS: In this retrospective observational case series, we reviewed the recorded data of the patients with unilateral extramacular choroidal melanoma treated with ruthenium - 106 (106Ru) plaque radiotherapy with a follow-up period of more than 6 months. Automatically measured OCTA retinal parameters were analysed after image processing. RESULTS: Thirty-one eyes of 31 patients with the mean age of 51.1 years were recruited. Six eyes had no radiation maculopathy (RM). From 25 eyes with RM, nine eyes (36%) revealed a burnout macular microvasculature with imperceptible vascular details. Twenty-one non-irradiated fellow eyes from the enrolled patients were considered as the control group. Foveal and optic disc radiation dose had the highest value to predict the burnout pattern (ROC, AUC: 0.763, 0.727). Superficial and deep foveal avascular zone (FAZ) were larger in irradiated eyes in comparison to non-irradiated fellow eyes (1629 µm2 vs. 428 µm2, P = 0.005; 1837 µm2 vs 268 µm2, P = 0.021; respectively). Foveal and parafoveal vascular area density (VAD) and vascular skeleton density (VSD) in both superficial and deep capillary plexus (SCP and DCP) were decreased in all irradiated eyes in comparison with non-irradiated fellow eyes (P < 0.001). Compared with non-irradiated fellow eyes, irradiated eyes without RM had significantly lower VAD and VSD at foveal and parafoveal DCP (all P < 0.02). However, these differences at SCP were not statistically significant. CONCLUSION: The OCTA is a valuable tool for evaluating RM. Initial subclinical microvascular insult after 106Ru brachytherapy is more likely to occur in DCP. The deep FAZ area was identified as a more critical biomarker of BCVA than superficial FAZ in these patients.

Efficacy and complications of ruthenium-106 brachytherapy for uveal melanoma: a systematic review and meta-analysis.

PURPOSE: The aim of this study was to evaluate the efficacy and vision-threatening complications of brachytherapy with ruthenium-106 (106Ru) plaque to treat uveal melanoma. MATERIAL AND METHODS: A literature review was performed based on results from searching PubMed, Embase, Web of Science, Scopus, and Cochrane databases, using the following key words: "choroidal melanoma", "uveal melanoma", "brachytherapy", and "ruthenium-106". We included studies performed on more than 30 patients since 1986, reporting on local control rate, complications rate, mean radiation dose, and mean tumor thickness. The cumulative analysis was performed using Metaprop command of Stata v.16, and meta-regression was conducted based on mean tumor thickness and mean radiation dose to tumor's apex. RESULTS: Twenty-one retrospective studies were selected, involving 3,913 patients treated primarily with 106Ru plaque brachytherapy. The range of radiation dose to tumor apex was from 70 Gy to 250 Gy. The local control rate following brachytherapy ranged from 59% to 98%, and the overall weighted mean of local control was 84%. However, the heterogeneity between studies' reports was remarkable (I 2 = 95.40%). Meta-regression based on tumor thickness and mean dose of radiation to the apex showed that the studies' heterogeneity was minimally related to the difference in mean tumor size (I 2 = 92%). The correlation between larger tumor size and lower local control rate was statistically significant (p-value = 0.024). There was no significant correlation between the mean radiation dose and local control rate (p-value = 0.679). The most commonly reported complications were cataract and radiation-related retinopathy. CONCLUSIONS: Although the studies' heterogeneity was high, in a prescription dose ranging from 70 Gy to 250 Gy to the tumor apex, 106Ru brachytherapy seems to be successful in local control of uveal melanoma. The efficacy of 106Ru in controlling uveal melanomas decreased with the increase in tumor thickness. However, these outcomes should be verified in randomized comparative studies.

Detection of radioactivity of unknown origin: Protective actions based on inverse modelling.

The detection of radioactivity of unknown origin necessitates the use of models that can quantify unknown corresponding source term parameters. In this work, a method for solving this inverse problem is described. The main goal of the method is that it can be used in emergency response. Therefore, the full modelling chain dealing with the collection and pre-processing of measurement data, source term estimation, (forward) dispersion modelling, and consequence assessment are discussed. Firstly, to verify this inverse model SHERLOC, the part of the modelling chain concerning the source term estimation based on measurement data, is applied to the first episode of the European Tracer Experiment (ETEX). Secondly, the complete model chain is applied to a release that is still unaccounted for; the 106Ru measured in the atmosphere of Europe in September and October of 2017. It is estimated that during the night of the 25th to the 26th of September 2017 approximately 1.33 PBq (1.33×1015 Bq) of 106Ru was emitted at a location in the region of the Southern Urals in the Russian Federation. Statistical indicators show that the modelled levels of concentration are in good agreement with the measurements. The radiological consequences of the release are estimated to be minor at distances farther than 22 km from the estimated source. However, in the vicinity of the emission the maximum committed dose received by the public may have exceeded 100 mSv. Since the presented approach can be executed within few hours after the collection of measurement data it can be used in the emergency response following the detection of radioactivity of unknown origin.

Long-Term Outcomes in Uveal Melanoma After Ruthenium-106 Brachytherapy.

Uveal melanoma is the most common primary intraocular malignancy. The aim of this retrospective study was to report the results after ruthenium-106 (Ru-106) plaque brachytherapy for uveal melanoma in terms of tumor control, visual acuity, radiation-related complications, tumor recurrence, metastases, and patients' survival rate during 4 years' follow-up. A total of 355 eyes from 355 patients have been treated with Ru-106 plaque brachytherapy for uveal melanoma between February 2011 and March 2020. Five patients were lost to follow-up, and then 350 eyes of 350 patients (mean age 58 ± 11 years) were enrolled in this retrospective study. All patients underwent a complete ophthalmic examination including echography and spectral domain-optical coherence tomography. The mean follow-up was 4 years (3 months to 9 years). After treatment, the mean tumor thickness was reduced to 1.75 ± 0.21 mm. Radiation complications were found in 63% of patients: 38% showed radiation maculopathy, 11% had optic neuropathy, and 14% developed cataracts. Cancer-free survival was 99%, 97%, and 85%, respectively, at 5, 7, and 9 years. Ru-106 plaque brachytherapy represents a reliable treatment of uveal melanoma. This technique is valid and safe with a low rate of ocular complications during a long-term follow-up.

Outcomes following Notched Ruthenium-106 Plaque Brachytherapy for Juxtapapillary Choroidal Melanomas.

PURPOSE: This study aimed to evaluate the outcomes of juxtapapillary choroidal melanomas treated with notched ruthenium-106 plaques. METHODS: Juxtapapillary choroidal melanomas (tumours within 2 disc diameters from the optic disc) treated with notched ruthenium-106 plaques (Eckert & Ziegler, BEBIG, Berlin, Germany) at the Scottish Ocular Oncology Service between 2009 and 2015 were retrospectively reviewed. The data were analysed with respect to various outcome measures including recurrence, complications, vision, and eye preservation. RESULTS: We reviewed 40 patients with a median tumour diameter of 8.4 mm (range 5-17 mm) and a median thickness of 2.5 mm (range 1.1-6 mm). AJCC tumour category distribution was 62.5% T1, 32.5% T2, and 5% T3 tumours. The mean presenting vision was 0.3 logMAR, and the mean final vision was 0.7 logMAR, with 62.5% retaining >1.0 logMAR and 50% retaining >0.3 logMAR at the final follow-up. The median follow-up was 51 months (14-100 months). Over the maximum follow-up time, 13 tumours (32.5%) recurred. Six of these were treated with salvage proton beam therapy (PBT), 2 with transpupillary thermotherapy followed by PBT, and 5 with enucleation. The final eye retention rate was 87.5%. Complications included maculopathy (10%), retinal detachment (5%), neovascular glaucoma (2.5%), and diplopia (2.5%). The observed risk of recurrence over 5 years was 31% (95% CI: 14.1%, 47.8%), and the risk of enucleation over 5 years was 11.5% (95% CI: 0.9%, 21.8%). CONCLUSION: Juxtapapillary choroidal melanomas treated with notched ruthenium plaques have a high recurrence rate and frequently need salvage treatment with PBT for tumour control. This has led to a change in our practice toward offering PBT as the first-line treatment for these patients.

Cherenkov Luminescence Imaging for Assessment of Radioactive Plaque Position in Brachytherapy of Uveal Melanoma: An In Vivo Feasibility Study.

Purpose: To study the feasibility of using Cherenkov luminescence imaging (CLI) to evaluate and document ruthenium-106 plaque position during brachytherapy of uveal melanoma. Methods: Ruthenium-106 decays by emitting high-energy beta particles. When the electrons pass through the eye, Cherenkov radiation generates a faint light that can be captured by highly sensitive cameras. Patients undergoing ruthenium-106 plaque brachytherapy for posteriorly located choroidal melanoma were examined by CLI, which was performed in complete darkness with an electron multiplying charged-coupled device camera mounted on a fundus camera modified for long exposures. Results: Ten patients with tumors ranging from 5.8 to 13.0 mm in largest basal diameter and 2.0 to 4.6 mm in height were included. The plaques had an activity between 0.035 and 0.089 MBq/mm2 at the time of examination (1-4 days after implantation). CLI revealed the actual plaque position by displaying a circular area of light in the fundus corresponding with the plaque area. The Cherenkov light surrounded the tumor as a halo, which showed some asymmetry when the plaque was slightly displaced. The light intensity correlated positively with plaque activity and negatively with tumor pigmentation. Exposure times between 30 and 60 seconds were required to display the plaque position and delineate the tumor area. The long exposures made it difficult to maintain stable eye fixation and optimal image quality. Conclusions: CLI is a novel method to assess and document ruthenium-106 plaque position in brachytherapy for uveal melanoma. Translational Relevance: Ocular CLI may provide relevant radiation data during and after implantation of radioactive plaques, thus improving the accuracy of episcleral brachytherapy.

High-dose ruthenium-106 plaque therapy for circumscribed choroidal hemangioma: a retrospective study of 25 Chinese patients.

AIM: To evaluate the efficacy and safety of ruthenium-106 (106Ru) plaque radiotherapy at a dose (>50 Gy) higher than recommended (29-50 Gy) for treatment of circumscribed choroidal hemangioma (CCH) in Chinese patients. METHODS: This retrospective study included 25 symptomatic CCH patients undergoing 106Ru plaque brachytherapy involving 25 eyes between January 2005 and August 2016. Ophthalmic examination was performed at the baseline and at each post-treatment follow-up visit, using best-corrected visual acuity (BCVA), dilated fundus examination, and B-scan ultrasonography. The primary efficacy outcome measures included the changes in BCVA and hemangioma dimensions at the last followup visit from the baseline. RESULTS: The mean follow-up duration was 28.0±26.6 (range, 12-110)mo. All the hemangiomas were located in the posterior pole except for two involving the fovea. The mean apex dose of 106Ru plaque radiotherapy was 84.4±19.7 Gy. The mean BCVA improved from 41.4±29.3 (0-97) at the baseline to 53.0±33.8 (0-97) ETDRS letters at the last visit (P=0.01). The mean hemangioma height declined from 3.98±0.88 (2.40-5.50) mm to 0.84±1.63 (0-6.47) mm (P≤0.001), and the greatest linear diameter (GLD) reduced from 9.36±2.23 (6.80-15.00) to 7.40±2.45 (0-13.00) mm (P≤0.001). Hemangioma size increased in one (4%) eye with a worsened vision, and subretinal fluid completely resolved in all but one patient (4%). Radiation-related retinopathy was observed in two patients at post-treatment 9 and 11mo, respectively. CONCLUSION: 106Ru plaque brachytherapy at a dose (>50 Gy) higher than recommended (29-50 Gy) is an effective treatment regimen for symptomatic CCH associated with significantly improved visual acuity and a favorable safety profile in Chinese patients.

Environmental radioactivity aspects of recent nuclear accidents associated with undeclared nuclear activities and suggestion for new monitoring strategies.

Recently environmental radionuclide signals were observed in the atmosphere which could be associated with undeclared nuclear activities, not directly connected with development of nuclear weapons. Large-scale contamination of European air with Ru-106 observed in 2017 may represent such an accident, which was probably associated with the Mayak nuclear fuel reprocessing facility in the Chelyabinsk region of Russia. A recently announced nuclear accident at Nyonoska in the Archangelsk region may represent an undeclared nuclear activity associated with the development of a nuclear jet engine which could be based on radionuclide energy generator or a small nuclear reactor. It is concluded that environmental radioactivity impacts associated with recent nuclear activities create new challenges for fast and reliable national and international monitoring systems which would require development of new monitoring strategies.

An episode of Ru-106 in air over Europe, September-October 2017 - Geographical distribution of inhalation dose over Europe.

Between the end of September and early October 2017, 106Ru was recorded by air monitoring stations across parts of Europe. In the environment, this purely anthropogenic radionuclide can be detected very rarely only. As far as known, 106Ru is only used in radiotherapy and possibly in radiothermal generators. Therefore, the episode drew considerable interest in the monitoring community, although the activity concentrations and resulting exposure were far below radiological concern. Health consequences can be practically excluded except possibly near the source. 106Ru in aerosols could be detected for several weeks and in some regions of Central and Eastern Europe tens, up to over 100 mBq/m³ were measured as one-day means. Discussions about a possible source continue until today (early 2019). Atmospheric back-modelling led to trajectories likely originating in the Southern to Northern Ural region of Russia and possibly Northern Kazakhstan. Suspiciously, no other anthropogenic radionuclides have been observed alongside, except minute concentrations of comparatively short-lived 103Ru (half life 39 d vs. 376 d for 106Ru). Due to the absence of other anthropogenic radionuclides, a reactor accident can be excluded, although both Ru isotopes are fission products generated in nuclear reactors. The exposure resulting from 106Ru activity concentration in air exceeded 200 mBq × d/m³ in some parts of Central and Eastern Europe. This leads to inhalation doses of up to about 0.3 µSv regionally, assuming the radiologically most efficient speciation, lacking better information, and inhalation dose conversion factors from ICRP 119. We show an interpolated map of the dose distribution over parts of Europe where sufficient measurements are available to us. Overlaying population density, we give an estimate of collective dose. The opportunity is also used to give a short review of origin, properties and use of 106Ru, as well as of accidents which involved release of this radionuclide.

Methods, results and dose consequences of 106Ru detection in the environment in Budapest, Hungary.

From late September to early October of 2017, the majority of European networks involved in environmental radiological monitoring - including the environmental monitoring system of the KFKI Campus in Budapest - detected 106Ru isotope of artificial origin in the atmosphere. The reported values higher than the minimum detectable activity (MDA) concentrations were in the range of 0.8 µBq/m3 - 145 mBq/m3. Based on the results of environmental measurements and the available meteorological data, assessments were made to analyze concentration levels of 106Ru activity and to help understand the behavior of radioruthenium in various environmental media. Evaluation of the daily variation of activity levels indicated a maximum of 4 day-long residence time of 106Ru contamination presence in ground level air in Budapest. An average 106Ru activity concentration of 25.6 ±â€¯1.4 mBq/m3 have been observed for the estimated residence time of 106Ru in the air. Deposition of 106Ru was dominantly influenced by rainfall, the major contributor wet deposition which led to an average of 11.3 ±â€¯1.3 Bq/m2 deposition on the ground surface prior to plume passage.

Outcome Analysis of Visual Acuity and Side Effect after Ruthenium-106 Plaque Brachytherapy for Medium-sized Choroidal Melanoma.

PURPOSE: The purpose of this study is to report on treatment outcomes for medium-sized choroidal melanoma treated with Ruthenium-106 (Ru-106) plaque brachytherapy. METHODS: A retrospective case series of 28 patients received Ru-106 brachytherapy treatment for choroidal melanoma. The prescribed tumor dose was 85 Gy to a depth of 5 mm. RESULTS: Median follow-up was 31.2 months. At 12 and 24-month postirradiation, the best corrected visual acuity ≥20/70 (LogMar ≥-0.54) was 53.8% and 64.2%, respectively. Median time to tumor regression was estimated to be 10 months (95% CI = 9-18 months), with 100% of response rate by 32 months. Radiation-induced side effects were limited, and there were no postradiation enucleations. CONCLUSIONS: The majority of patients maintained good visual acuity, with no enucleations and minimal side effects. In this cohort, the Ru-106 plaque brachytherapy proved to be an efficacious and safe treatment option for patients with medium-sized choroidal melanomas with a maximal tumor height of 5 mm.