Apex Dose Research Articles

Management of diffuse choroidal hemangioma in Sturge-Weber syndrome with Ruthenium-106 plaque radiotherapy

To evaluate Ruthenium-106 plaque radiotherapy in the treatment of diffuse choroidal hemangioma (DCH) associated with serous retinal detachment. A retrospective analysis was performed in five patients treated for DCH associated with Sturge-Weber syndrome (SWS). In all cases, Ruthenium-106 plaque therapy with a target apex dose of 30.98-47.36 Gy (mean:38.9 Gy) was performed. The outcomes of treatment were regression of DCH, assessed by B-scan ultrasonography; resolution of serous retinal detachment, measured by B-scan ultrasonography and optical coherence tomography (OCT); changes in best corrected visual acuity (BCVA) and the development of radiation-related complications. All investigations were repeated 3 months after treatment and then at six monthly intervals within 22-122 months (mean: 62 months) of follow-up. The initial BCVA of the affected eyes ranged from counting fingers at 1 m to 0.1 by the Snellen chart. Mean tumor basal diameter was 16.7 mm (range: 13.8 to 18.5 mm) and mean tumor thickness was 4.4 mm (range: 2.4 to 5.8 mm). Tumor regression was found in all cases with the prompt resolution of subretinal fluid. In three patients, BCVA improved and in two it remained stable. During the follow-up period, in one case secondary glaucoma was treated with transscleral cyclophotocoagulation, and in another case, recurrence of the hemangioma was treated with repeated Ruthenium-106 plaque irradiation and transpupillary therapy. Ruthenium-106 plaque radiotherapy is an effective and safe treatment option for DCH associated with SWS. Brachytherapy led to tumor regression and resolution of serous retinal detachments, and visual stabilization was achieved in most cases.

A novel intracavitary applicator design for the treatment of deep vaginal fornices: preliminary dose metrics and geometric analysis.

PurposeTo investigate the dose distributions associated with a novel balloon sleeve placed over a standard cylinder applicator.Material and methodsA computed tomography (CT) scan of a sleeve balloon shaped to inflate into the vaginal fornices was used to digitize 1-, 3-, and 5-catheter configurations. Point doses for rectum, apex, and fornix were calculated and compared to the values associated with a standard cylinder plan not targeting the vaginal fornices. Inflation of the sleeve balloon in the vaginal fornices and dose coverage with constraints to the rectum, bladder, and sigmoid D2cc were evaluated.ResultsRectum, apex, and fornix doses were respectively 76%, 119%, and 44% for a standard cylinder; 190%, 310%, and 93% for a 1-catheter configuration; 98%, 109%, and 109% for a 3-catheter configuration; and 91%, 107%, and 96% for the 5-catheter configuration. In a patient analysis, expansion of the sleeve balloon into the vaginal fornices was confirmed. The 5-catheter configurations were associated with best coverage of the fornices and acceptable doses to rectum, bladder, and sigmoid.ConclusionsA 1-catheter configuration cannot be used clinically due to high rectal and apex dose. In theoretical analysis, the 3- and 5-catheter configurations showed > 96% coverage to the vaginal fornices with a clinically acceptable rectal dose. In a treatment simulation in a patient, a 5-catheter configuration showed 90% coverage of the fornices with acceptable doses to the organs at risk. The treatment of deep vaginal fornices results in an increased rectal dose compared to a standard cylinder plan.

Intraretinal hyperreflective spots in eyes with radiation induced maculopathy

AbstractPurpose To evaluate in vivo the presence of intraretinal hyperreflective spots in eyes with radiation induced maculopathy.Methods 25 subjects affected by maculopathy secondary to eye irradiation for a primary uveal melanoma were enrolled. All eyes previously underwent I‐125 brachytherapy with a standard apex dose (85 Gy). Full ophthalmic examination, including spectral domain‐OCT (SD‐OCT) and fluorescein angiography, was performed in all eyes. After segmentation of retinal layers, retinal images were analyzed for reflectivity changes (hyperreflectivity spots) at the level of: internal limiting membrane plus retinal nerve fiber layer (ILM+RNFL), inner nuclear layer plus outer plexiform layer (INL+OPL) and outer nuclear layer (ONL). Hyperreflective spots were analyzed in a full retinal section both in the foveal area, and between 500 and 1500 µm from the foveal center. All examinations were performed twice, by two independent masked graders. Results The inter‐grader agreement was at least substantial for all measurements. In all studied eyes hyperreflective spots were detected by SD‐OCT. Hyperreflective spots were mainly located in the inner retina (ILM+RNFL and INL+OPL) compared to the outer retina (ONL) (p<0.005), and their expression significantly progressed with the progression of macular (radiation induced) edema (p= 0.002). Conclusion The presence of hyperreflective spots may represent an in vivo biomarker of retinal microglia activation in radiation maculopathy, as previously shown in other macular disorders. This aspect may be related to the so‐called senescence process induced by irradiation of solid tumors. This phaenomenon may offer more tailored approaches for the treatment of radiation‐induced maculopathy.

Plaque Radiotherapy in the Management of Scleral-Invasive Conjunctival Squamous Cell Carcinoma

Conjunctival squamous cell carcinoma (SCC) is surgically managed with wide surgical excisional biopsy, superficial keratectomy, and cryotherapy. In eyes with residual tumor showing scleral invasion or intraocular involvement, enucleation is advised. To explore the role of plaque radiotherapy for residual invasive conjunctival SCC as an alternative to enucleation. Interventional case series involving 15 patients with histopathologically confirmed scleral and/or intraocular invasion of SCC at Wills Eye Hospital. Plaque radiotherapy. Tumor control, treatment complications, and globe salvage. The primary tumor prior to excision displayed a mean basal diameter of 12.1 mm (median, 12 mm; range, 4-25 mm) and mean thickness of 2.6 mm (median, 3 mm; range, 1-5 mm). In all cases, the tumor was managed by primary surgical resection using wide excisional biopsy, limited superficial keratectomy, and cryotherapy to the remaining conjunctival margins. Histopathology confirmed conjunctival SCC in all cases with residual tumor demonstrating scleral invasion (n = 15) and/or anterior chamber invasion (n = 3). The residual tumor measured a mean basal diameter of 10.6 mm (median, 10 mm; range, 2.5-20 mm) and mean thickness of 1.5 mm (median, 1 mm; range, 1-5 mm). Plaque radiotherapy was applied in all cases for a mean apex dose of 56 Gy (median, 50 Gy; range, 50-80 Gy) over a mean of 132 hours (median, 142 hours; range, 93-170 hours). Over a mean follow-up of 41 months (median, 46 months; range, 9-96 months), local tumor control was achieved in all 15 cases (100%). However, 4 cases showed further distant conjunctival tumor recurrence remote from the site of radiotherapy with positive orbital involvement at a mean of 5 months postradiotherapy, necessitating enucleation (n = 2) or orbital exenteration (n = 2). Globe salvage was achieved in 10 cases, as 1 patient required enucleation for chronic ocular irritation. Radiation complications included cataract (n = 13), iris telangiectasia (n = 5), corneal epithelial defect (n = 4), corneal edema (n = 3), and glaucoma (n = 1). There was no evidence of metastasis. Plaque radiotherapy delivered over a mean of 6 days can be an effective alternative to enucleation for residual scleral-invasive conjunctival SCC following resection. Local tumor control was achieved in all cases.

Uveal Melanoma Treated With Iodine-125 Episcleral Plaque: An Analysis of Dose on Disease Control and Visual Outcomes

To investigate, in the treatment of uveal melanomas, how tumor control, radiation toxicity, and visual outcomes are affected by the radiation dose at the tumor apex. A retrospective review was performed to evaluate patients treated for uveal melanoma with (125)I plaques between 1988 and 2010. Radiation dose is reported as dose to tumor apex and dose to 5 mm. Primary endpoints included time to local failure, distant failure, and death. Secondary endpoints included eye preservation, visual acuity, and radiation-related complications. Univariate and multivariate analyses were performed to determine associations between radiation dose and the endpoint variables. One hundred ninety patients with sufficient data to evaluate the endpoints were included. The 5-year local control rate was 91%. The 5-year distant metastases rate was 10%. The 5-year overall survival rate was 84%. There were no differences in outcome (local control, distant metastases, overall survival) when dose was stratified by apex dose quartile (<69 Gy, 69-81 Gy, 81-89 Gy, >89 Gy). However, increasing apex dose and dose to 5-mm depth were correlated with greater visual acuity loss (P=.02, P=.0006), worse final visual acuity (P=.02, P<.0001), and radiation complications (P<.0001, P=.0009). In addition, enucleation rates were worse with increasing quartiles of dose to 5 mm (P=.0001). Doses at least as low as 69 Gy prescribed to the tumor apex achieve rates of local control, distant metastasis-free survival, and overall survival that are similar to radiation doses of 85 Gy to the tumor apex, but with improved visual outcomes.

Palladium-103 Plaque Radiation Therapy for American Joint Committee on Cancer T3- and T4-Staged Choroidal Melanomas

Patients with larger choroidal melanomas are being treated with plaque radiation therapy. To report the methods and results of palladium-103 brachytherapy for American Joint Committee on Cancer, 7th edition, T3- and T4-sized choroidal melanomas. A retrospective analysis of the results of a clinical case series over a 10-year period of 47 consecutive patients with uveal melanoma. The patients were treated at The New York Eye Cancer Center, Beth Israel Comprehensive Cancer Center, or The New York Eye and Ear Infirmary between 2002 and 2012 and had a minimum follow-up of 6 months. Tumors had a mean preoperative apical tumor height of 8.6 mm and a mean largest basal diameter of 15.8 mm. We analyzed, but were not limited to, data on the methods of radiation therapy, local tumor control, adverse effects, vision retention, and metastatic rate. All patients completed therapy and received the prescribed tumor apex dose. At a median of 47 months (range, 6-125 months), the rate of local control was 91% and the rate of eye retention was 89%. The most common long-term brachytherapy-related complication was radiation maculopathy (66% of patients), followed by radiation optic neuropathy (51% of patients). One or both of these complications were diagnosed at a mean time of 16 months (range, 2-36 months) after brachytherapy. Secondary cataract developed in 36% of patients. Glaucoma developed in 17% of patients and resulted in enucleation in 4% of patients. The mean pretreatment visual acuity was 20/50 (range, 20/12.5 to hand motions), which evolved to a mean visual acuity of 20/100 (range, 20/20 to no light perception). Overall, 25 of 47 patients (53%) maintained 20/200 or better vision. Metastatic melanoma developed in 32% of patients. Palladium-103 ophthalmic plaque radiation therapy can be used as an eye- and vision-preserving treatment for relatively large American Joint Committee on Cancer T3- or T4-sized choroidal melanomas.

SU-E-T-349: An Optimized Dosimetric Study of a Multi-Channel Vaginal Cylindrical Applicator in Brachytherapy

Purpose: Toptimized dosimetry of a CT/MRI multi‐lumen brachytherapy applicator was planned to treat vaginal cancer after hysterectomy. Multichannel design of cylinder includes several peripheral channels isotropically placed 5mm inside cylinder from surface with a separate central channel to allow single lumen brachytherapy as an option. The optimized dosimetry plans were compared between single‐channel versus multi‐channel to determine the sufficient coverage to the vaginal apex and other potential dosimetric advantages. Methods: CT simulation for each treatment of vaginal brachytherapy of postoperative endometrial or vaginal cancer. Seventeen CT image data sets were collected in this study. Standard single channel treatment was planned. Prescribed dose was to the 5mm cuff from the cylinder surface. PTV of 5mm rind with prescribed length was constructed. Doses to PTV and ROIs such as bladder and rectum were documented in DVH. Dose point to the apex of 5mm rind which locates at 5mm from applicator tip was specified. A second brachytherapy plan was generated using a multi‐channel loading. DVH of 5mm rind coverage, doses to apex, bladder and rectum were optimized in Oncentra brachytherapy planning system. Results: Optimized 95% to V95 and lower dose to adjacent structures were reported in multi‐channel plan. Improvements to apex dose by 3‐5% and organ sparing by 7‐14% were achieved. At the apex, inverse planning was further optimized by adjusting unequal contribution selectively from multi‐channel end. It is difficult for single channel to eliminate the cold spot at apex and maintain the dose uniformity to the 5mm cuff simultaneously. Conclusion: Possible optimization of brachytherapy treatment planning of vagina is investigated in this study by using a new multi‐lumen vaginal cylinder. The new device can increase the therapeutic ratio by improving target coverage and at the apex region as well. A reduction in the potential toxicity to the adjacent critical organs is feasible.

Ruthenium plaque radiation therapy for iris and iridociliary melanomas

To determine the long-term effects of ruthenium-106 plaque radiation therapy for iris and iridociliary melanomas in terms of tumour regression and complications. Between 1 November 1997 and 31 December 2007, 36 patients with an iris or iridociliary melanoma were treated with Ruthenium-106 (Ru-106) ophthalmic plaque radiation therapy. The median follow-up was 6.5 years with a range of 2-11 years. The mean tumour apex dose was 151.5 Gy. Main outcome measures were local tumour control and radiation-related ocular complications. The mean age of the patients at the time of treatment was 54 years (range 14-82). The tumours had a median largest basal dimension of 4.8 mm (range 3-11) and a prominence of 2.3 mm (range 0.8-5), with a median involvement of three clock hours (range 1-6). The tumours were confined to the iris in 14 patients (39%), extended into the anterior ciliary body in 12 (33%), while the anterior ciliary body tumour extended into the iris in ten patients (28%). Tumours regressed in all patients (100%) with a mean regression of 80% of the original tumour size at 7 years of follow-up. Radiation-related complications included corneal erosions on the first postoperative day in nine patients (25%), cataract in four of 11 patients free of cataract before treatment (36%) and postradiation glaucoma in one patient (3%). Visual acuity of 20/200 or worse was present in one of 20 patients (5%) at 6 years of follow-up. Local recurrences occurred in two patients (5%), 2 and 5 years after the radiation therapy respectively, and both underwent enucleation. Distant metastases occurred in one of these enucleated patients (3%) 2 years after treatment. Ru-106 plaque radiation therapy for iris and iridociliary melanoma resulted in good local tumour control and preservation of visual acuity with few and treatable side-effects.

Expression of 12 cytokines in aqueous humour of uveal melanoma before and after combined Ruthenium‐106 brachytherapy and transpupillary thermotherapy

To determine the aqueous humour levels of 12 cytokines in eyes with uveal melanoma and whether their expression changes after combined Ru-106 brachytherapy and transpupillary thermotherapy (TTT). Aqueous humour samples were collected from 20 patients with previously untreated uveal melanoma undergoing combined Ru-106 brachytherapy and TTT, both at the time of plaque placement and removal. Using multiplex biochip array technology, 12 different cytokines were measured, including interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, vascular endothelial growth factor (VEGF), tumour necrosis factor (TNF)-α, interferon (IFN)-γ, epidermal growth factor (EGF) and monocyte chemoattractant protein (MCP)-1. Aqueous humour from 20 patients undergoing cataract surgery was used as control. IL-6, IL-8, IFN-γ and MCP-1 were highly expressed in uveal melanoma, whereas IL-2, IL-10 and TNF- α were low in expression. There was a positive correlation between tumour height and IL-8 level (p = 0.020). Vascular endothelial growth factor tends to be highly expressed in melanoma-containing eyes (p = 0.056). Levels of IL-6, IL-8 and IL-1β increased after the mean 117 ± 38 hrs of brachytherapy and adjunctive TTT with a tumour apex dose of 61 ± 28 Gy and a scleral contact dose of 786 ± 226 Gy. Increase in levels of IL-6 (p = 0.003) and IL-8 (p = 0.046) positively correlated with scleral contact dose. Cytokines such as IL-6, IL-8, IFN-γ and MCP-1 may be implicated in the progression of uveal melanoma. Ocular irradiation from a Ru-106 plaque promoted an increase in the levels of IL-6, IL-8 and IL-1β, modulation of which could be useful in managing radiation-related side effects.

Lack of Radiation Maculopathy After Palladium-103 Plaque Radiotherapy for Iris Melanoma

To report on the risk of radiation maculopathy for iris and iridociliary melanomas treated by (103)Pd plaque radiotherapy. This is a retrospective clinical case series of 30 eyes in 30 patients with melanomas limited to the iris or invading the ciliary body. The main outcome measures included demographic information, laterality, tumor size, location, visual acuity, radiation dose, local control, retinal evaluation, and duration of follow-up. Thirty patients were followed for a median 36 months (range, 12-90 months). Sixteen of 30 tumors (53%) were pure iris melanomas, and 14 (47%) were primary iris melanomas extending into the ciliary body. Radiation dosimetry showed that the median tumor apex dose was 85 Gy (range, 75-100 Gy), lens dose 43.5 Gy (range, 17.8-60 Gy), fovea dose 1.8 Gy (range, 1.3-5 Gy), and central optic disc dose 1.7 Gy (range, 1.3-4.7 Gy). Cataracts developed in 20 of the 28 phakic eyes (71.4%). No patient in this series developed radiation maculopathy or radiation optic neuropathy. Last best-corrected visual acuity was ≥ 20/25 in 28 patients (93%) at a median 36 months' follow-up. Though visual acuities were transiently affected by radiation cataract, no radiation maculopathy or optic neuropathy has been noted after (103)Pd treatment of iris and iridociliary melanomas.

Management of Retinal Vasoproliferative Tumor Associated with ROP by Plaque Brachytherapy

The authors report a secondary exudative vasoproliferative tumor of the retina associated with retinopathy of prematurity, managed by plaque radiotherapy. A 15-year-old girl with a history of mild, stable retinopathy of prematurity in both eyes noted progressively reduced visual acuity to hand motions in the left eye. Examination disclosed a vasoproliferative tumor of 10-mm base and 3.5-mm thickness with near total (macula-off) exudative retinal detachment. She was treated with iodine-125 plaque radiotherapy, giving apex dose of 40 Gy over 4 days. The tumor regressed to 1.9 mm and retinal detachment resolved 8 months following therapy. Epiretinal membrane with significant macular pucker and edema later developed and was managed with pars plana vitrectomy and membrane peeling. Visual acuity was counting fingers due to photoreceptor loss. Retinopathy of prematurity is a rare cause of vasoproliferative tumor. Iodine-125 plaque radiotherapy can lead to tumor regression and reattachment of the retina in such cases.

Influence of Customized 125I Plaque Radiotherapy Design on Dosimetry Related to Iris Melanoma

Materials/Methods: The diagnosis of iris melanoma was documented after opthalmoscopic evaluation, fundus photography, ultrasound biomicroscopy, and demonstrable tumor enlargement over time. Patients were treated with customized episcleral 125I plaque radiotherapy as an alternative to the surgical intervention that enucleation entails. Management of this tumor is largely dependent on tumor size and seeding. Tumor seeding often accompanies the spread of iris melanoma and invasive procedures can shed malignant cells into the circulation. Iodine-125 seeds (Model 6711; Oncura) were affixed to the plaques to deliver a prescribed tumor apex dose of 70 Gy (TG-43 formalism). Small size plaques (10 mm) were loaded in a ladder design, while medium (15 mm) and large (18 mm) were symmetric pinwheel or outer circumference patterns. To achieve the prescription dose of 70 Gy (TG-43), seed strengths ranging from 1.98 to 4.84 mCi/seed were used and corresponding dose rates of 58-75 cGy/hr were calculated. The plaques are typically planned, using the BEBIG treatment planning software, to deliver the prescribed dose in 4 days.

Tumorregression maligner Aderhautmelanome nach Transpupillarer Thermotherapie (TTT) versus Ruthenium-Brachytherapie und Sandwichtherapie – eine vergleichende Analyse

The aim of this study was to evaluate tumour regression in a large series of choroidal melanomas, which were treated with three different eye-sparing treatment modalities. Retrospective review of the treatment results in all eyes with malignant choroidal melanoma, which were treated in the University Eye Clinic of Mainz consecutively in the time span 1.1992 to 12.2000 with transpupillary thermotherapy (TTT, standard protocol Oosterhuis JA 1995), ruthenium brachytherapy (RB, tumor apex dose 150 Gy) or sandwich therapy (ST). One-step ST was defined as TTT followed by RB with 100 Gy tumor apex dose within 48 hours. The treatment of residual prominences with TTT secondary to RB after different time spans was called two-step ST. Follow-up was 2 years. 131 eyes with malignant choroidal melanoma (mean tumour thickness: 4.5 mm) were treated with RB (66 eyes), TTT (26 eyes) or ST (39 eyes). Preservation of the globe was achieved in 109 eyes (81 %). Local tumour control was found in small melanomas (prominence up to 3 mm) in 89 %, in large tumors (prominence 8 mm and higher) in 50 %. In a subgroup of small posterior melanomas (n = 70 eyes, prominence up to 4.5 mm, located posterior to the equator) local tumour control was noted in 91 %. The time span to reach local tumour control (Kaplan-Meier estimates) was the shortest after TTT (median: 20 weeks), compared with RB (48 weeks) and one-step ST (29 weeks). In choroidal melanomas the chance of local tumour control and preservation of the globe decreases with increase of the tumour prominence. In small choroidal melanomas with posterior location local tumour control was achieved significantly faster after TTT than after RB.

High-dose iodine-125 episcleral brachytherapy for circumscribed choroidal haemangioma

AimsTo evaluate episcleral plaque radiotherapy with high-dose 125I for the treatment of circumscribed choroidal haemangioma (CCH).MethodsA retrospective review was performed of patients treated for CCH between 1995 and 2007. Brachytherapy...

The treatment of uveal melanoma by ruthenium plaques

Abstract Purpose Plaque radiotherapy is the first choice of treatment for choroidal melanomas. The standard practice is to position the plaque centrically in relation to the tumour, with a 2mm physical safety margin in all directions. The author has developed techniques for administering brachytherapy with plaques positioned eccentrically, with their posterior edge aligned with the posterior tumour margin. This allows a higher apex dose to be given while reducing the radiation delivered to optic nerve and fovea. Methods The tumour is localized by transillumination and its anterior margin marked on the sclera with a pen. The 'plaque‐tumour difference' measurement is then marked on the sclera at the point where the anterior plaque margin should be. A transparent plaque template is sutured to the sclera. The position of the plaque is checked with a right‐angled fibre‐optic transilluminator, which is passed through a perforation near the posterior edge of the template. If the template is positioned correctly, then with binocular indirect ophthalmoscopy one should see the 'sunset sign', which occurs when the transilluminator is exactly at the posterior tumour margin. Results Eccentric ruthenium plaque positioning has been practised in Liverpool for over a decade. The results have been published. Local tumour control rates have been good (partly because of case selection). Radiation maculopathy and optic neuropathy have been rare if the tumour has not extended within 1 mm of these structures. The main cause of visual loss has been maculopathy, caused by exudation from the irradiated tumour. Methods for treating such exudation are described. Conclusion Plaque radiotherapy is effective for choroidal melanomas up to 5 mm in thickness. It achieves good local tumour control with preservation of vision in most cases.

SU‐FF‐T‐32: Optimized Dose Distribution of Gammamed Plus Vaginal Cylinders

Purpose: The aim of this study was to optimize dose distribution for Gammamed plus vaginal cylinders and the placement of dose optimization points was evaluated for its effect on optimized dose distributions. Materials and methods: The HDR source travels through the central tandem, distal to proximal, stopping at dwell positions defined by step sizes. Two different dose optimization point models were used in this study namely, non apex (dose optimization points only on periphery) and apex (dose optimization points on periphery and along the curvature including the apex points). Thirteen dwell positions were used for the HDR dosimetry to obtain a 6 cm active length. Diameters of vaginal cylinders varied from 2.0 to 4.0 cm. Iterative optimization routine was utilized for all optimizations. The effects of various optimization routines (iterative, geometric, equal times) was studied for the 3.0 cm diameter vaginal cylinder. The effect of source travel step size on the optimized dose distributions for vaginal cylinders was also evaluated. Results: For both non‐apex and apex models of vaginal cylinders, doses for apex point and three dome points were higher for apex model compared to non‐apex model. Mean doses to the optimization points for both the cylinder models and all the cylinder diameters were 6 Gy matching with the prescription dose of 6.00 Gy. Iterative optimization routine resulted in the highest dose to apex point and dome points. The mean dose for optimization point was 6.01 Gy for iterative optimization and was much higher than 5.74 Gy for geometric and equal times routines. Conclusion: In our study best doses were obtained for the optimization points for 1 cm step size and iterative optimization routine for the apex model vaginal cylinder. Selection of dose optimization points for the derivation of optimized dose distributions for vaginal cylinders affects the dose distributions.

Imaging techniques in the dosimetry of epiescleral brachytherapy

Abstract Purpose To compare the doses calculated from the measurements of the tumour obtained by different imaging techniques. Methods It is a retrospective study of 50 enucleated eyes corresponding to 50 patients with diagnosis of choroidal melanoma. For every case, there was recorded information about height of the tumour obtained by means of studies of pathological anatomy both in the macroscopic and in the microscopic preparation, and the obtained with the available imaging techniques for this measurement: magnetic nuclear resonance RNM, computerized tomography CT and B ultrasound US. Dose distribution was calculated in the tumour apex by means of the brachytherapy treatments planning system Bebig for three applicators type COMS of three and all slots filled for a duration of treatment of 1 hour, and was analyzed later by a spreadsheet Excel and the statistical application SPSS. Results Apex dose differences (%) Comparison with the macroscopic preparation Applicator size 10 mm 16 mm 22 mm CT 16,5 14,8 13,4 MNR 3,6 4,9 5,5 US 6,0 7,3 5,0 Conclusion Obtained results can be influenced partly by the size of the studied tumours, in the main of big size, and for the small muestral size in someone of the imaging techniques. They show the importance of the election of the imaging technique to obtain the information for dosimetry. Particularly relevant they are the obtained ones in the comparison with the CT due to the difficulty for this technology of distinguishing between the tumour and the detachment of retina associated. Acknowledgments: This work has been financed partly by a grant of the Junta de Castilla y León (Order SAN/1829/2007 of November 13, BOCYL of November 15, 2007)

Optimized Dose Distribution of Gammamed Plus Vaginal Cylinders

Endometrial carcinoma is the most common malignancy arising in the female genital tract. Intracavitary vaginal cuff irradiation may be given alone or with external beam irradiation in patients determined to be at risk for locoregional recurrence. Vaginal cylinders are often used to deliver a brachytherapy dose to the vaginal apex and upper vagina or the entire vaginal surface in the management of postoperative endometrial cancer or cervical cancer. The dose distributions of HDR vaginal cylinders must be evaluated carefully, so that clinical experiences with LDR techniques can be used in guiding optimal use of HDR techniques. The aim of this study was to optimize dose distribution for Gammamed plus vaginal cylinders. Placement of dose optimization points was evaluated for its effect on optimized dose distributions. Two different dose optimization point models were used in this study, namely non-apex (dose optimization points only on periphery of cylinder) and apex (dose optimization points on periphery and along the curvature including the apex points). Thirteen dwell positions were used for the HDR dosimetry to obtain a 6-cm active length. Thus 13 optimization points were available at the periphery of the cylinder. The coordinates of the points along the curvature depended on the cylinder diameters and were chosen for each cylinder so that four points were distributed evenly in the curvature portion of the cylinder. Diameter of vaginal cylinders varied from 2.0 to 4.0 cm. Iterative optimization routine was utilized for all optimizations. The effects of various optimization routines (iterative, geometric, equal times) was studied for the 3.0-cm diameter vaginal cylinder. The effect of source travel step size on the optimized dose distributions for vaginal cylinders was also evaluated. All optimizations in this study were carried for dose of 6 Gy at dose optimization points. For both non-apex and apex models of vaginal cylinders, doses for apex point and three dome points were higher for the apex model compared with the non-apex model. Mean doses to the optimization points for both the cylinder models and all the cylinder diameters were 6 Gy, matching with the prescription dose of 6 Gy. Iterative optimization routine resulted in the highest dose to apex point and dome points. The mean dose for optimization point was 6.01 Gy for iterative optimization and was much higher than 5.74 Gy for geometric and equal times routines. Step size of 1 cm gave the highest dose to the apex point. This step size was superior in terms of mean dose to optimization points. Selection of dose optimization points for the derivation of optimized dose distributions for vaginal cylinders affects the dose distributions.

Visual acuity after Ruthenium 106 brachytherapy of choroidal melanomas

To report on conservation of visual acuity after Ruthenium(106) (Ru-106) brachytherapy of choroidal melanoma. This study was a noncomparative interventional case series of 458 patients with choroidal melanoma treated at a single center between January 1993 and December 2001. The intervention consisted of Ru-106 brachytherapy delivering minimum scleral and apex doses of 300 Gy and 80 Gy, respectively, using a 15-mm or 20-mm plaque. For discrete, posterior tumors, the plaque was positioned eccentrically with its posterior edge aligned with the posterior tumor margin. To ensure correct plaque positioning, any overlying extraocular muscles were dis-inserted, and the locations of both tumor and plaque edges were confirmed by transillumination and indentation. The main outcome measures were conservation of vision of 20/40 or better, 20/200 or better, and Counting Fingers or better, according to baseline variables. The actuarial rate of conservation of 20/40 or better was 55% at 9 years, loss of such vision correlating with posterior tumor extension (p < 0.001), temporal tumor location (p = 0.001), increased tumor height (p = 0.01), and older age (p < 0.01) (Cox multivariate analysis). Similar analyses showed conservation of 20/200 or better in 57% of eyes at 9 years, loss correlating with reduced initial visual acuity (p < 0.001), posterior tumor extension (p < 0.001), and temporal tumor location (p = 0.006). Counting Fingers or better vision was conserved in 83% of patients at 9 years, loss correlating with increased tumor height (p < 0.0001). Local tumor recurrence occurred in 9 patients (actuarial rate, 3% at 9 years). Ruthenium(106) brachytherapy of posterior choroidal melanoma achieves good conservation of vision if the tumor does not extend close to the optic nerve or fovea.

Palladium 103 (103Pd) Plaque Radiation Therapy for CircumscribedChoroidal Hemangioma With Retinal Detachment

To describe clinical experience with palladium 103 ((103)Pd) ophthalmic plaque radiotherapy for choroidal hemangioma. One course of (103)Pd ophthalmic plaque radiotherapy was used in each of 5 patients with circumscribed choroidal hemangioma who had progressive loss of vision due to subretinal exudation. A mean apex dose of 2900 cGy (2900 rad) was delivered. Functional tests of outcome included best-corrected visual acuity. Anatomic results included changes in tumor height and subretinal fluid documented by ophthalmoscopy, fluorescein angiography, and ultrasonography. All patients had complete resolution of subretinal fluid with reattachment of the retina. All tumors decreased in height (mean, 50%) after treatment. Three patients (60%) demonstrated improvement in visual acuity at the last follow-up, and in 1 patient vision remained stable with resolution of metamorphopsia. Twenty-four months after treatment, 1 patient whose visual acuity had recovered from 20/160 to 20/32 had a loss of vision to 20/160 because of radiation maculopathy. For all patients, a mean visual acuity improvement of 2 lines was documented (95% confidence interval, 0.23-0.88). Mean follow-up was 18.6 months (range, 6-29 months). A single (103)Pd plaque radiation treatment was effective in decreasing tumor height, eliminating subretinal fluid, and improving visual acuity in patients with symptomatic circumscribed choroidal hemangiomas.