Clinical Investigations
Diode-light transillumination for ophthalmic plaque localization around juxtapapillary choroidal melanomas

https://doi.org/10.1016/S0360-3016(99)00064-4Get rights and content

Abstract

Purpose: An evaluation of plaque-mounted diode-light transillumination (DLT) for localization of episcleral plaques beneath juxtapapillary tumors.

Methods and materials: Two patients scheduled for radiotherapy for juxtapapillary melanomas were offered DLT as an additional method of ophthalmic plaque localization. Plaques were constructed by affixing 4 non-heat producing, light-emitting diodes with their apertures flush with the episcleral outer surface of the plaque’s rim. Bio-implantable epoxy was used to encapsulate the electronic components. Then the plaques were loaded with 103Pd seeds. After the eye-plaques were sewn to the episclera covering the base of the intraocular tumors; the diode-lights were illuminated, viewed and recorded. Photodocumentation of the relative position of the 4 lights around tumor’s base was obtained in both cases.

Results: Digital images of plaque-mounted diode retro-transillumination were obtained. No evidence of diode-light toxicity was noted. Both tumors were found to be covered by the ophthalmic plaques.

Conclusion: Juxtapapillary tumors are often difficult or impossible to visualize with standard transillumination techniques and have been associated with poor local control rates. We have developed plaque-mounted DLT in an effort to improve ophthalmic plaque localization. Retrobulbar transillumination was viewed by indirect ophthalmoscopy and recorded with video-imaging. This technique provides unique photographic documentation of episcleral plaque localization beneath juxtapapillary tumors.

Introduction

Transillumination of an eye containing an intraocular tumor can reveal the tumors shadow on the sclera. To aid radioactive plaque insertion, the edges of the shadow are marked on the sclera with tissue dye. Then the radioactive eye-plaque is sewn onto the sclera as to cover the tumor shadow, plus a 2- to 3-mm shadow-free margin. This is the most commonly used technique for radioactive plaque localization 1, 2, 3. This type of transillumination works well for intraocular tumors with borders that extend anterior to the eyes equator. However, small posterior and juxtapapillary tumors can be more difficult or impossible to transilluminate 1, 4. When standard transillumination fails, localization of radioactive-plaques usually requires the use of ophthalmoscopy with scleral depression and/or ultrasonographic localization techniques 4, 5, 6, 7. The increased incidence of failure of plaque radiotherapy of juxtapapillary tumors may be attributed (in part) to difficulties with plaque placement 1, 4, 8, 9, 10. Most ocular tumor specialists agree that accurate plaque placement is critical to successful radiation therapy and that failure of local control may reduce a patient’s chance of survival 1, 11, 12, 13. These factors underscore the need for methods to ensure and document proper plaque placement.

We have developed a system of plaque-mounted diode-lights for localization of episcleral plaques beneath juxtapapillary tumors (14). This study is unique in that 4 lights were attached to the eye plaque, implanted, illuminated, and photographed with digital imaging. We describe DLT-plaque construction, insertion, illumination, and photographic documentation.

Section snippets

DLT-plaque construction

Four non-heat producing, light-emitting diode-lights [Lumex SSL-LXA228SRC-TR1125 (Palatine, IL, USA), angle of dispersion:25 degrees, clear lens, 170mcd @20ma, 660 nanometers)] were affixed to gold eye-plaques with their apertures flush with the episcleral rim (Fig. 1). Then, a 2 conductor female-connector with wires (Nanoseries-2, Omnetics Connector, Inc., Minneapolis, MN, USA) was affixed flush with the posterior wall of the plaque and above the suture eyelets. The wires were connected to

Results

DLT light intensity was modulated such that 4 distinct point sources could be visualized (Fig. 2). By the end of plaque insertion, the results of standard transillumination, ultrasound, and DLT were all consistent with optimum plaque placement.

Indirect ophthalmoscopy with video imaging could be optimized if the light from the indirect ophthalmoscope was minimized. We found that DLT was also affected by plaque-scleral contact. Plaque-tilt and episcleral soft tissue would diffuse the light,

Discussion

Ophthalmic plaque positioning has been studied utilizing a number of radiographic and ultrasound techniques 4, 5, 6, 7, 16, 17, 18. While each modality offers unique perspectives, only plaque-mounted DLT allows for direct visualization and photodocumentation of the plaque-edges surrounding the intraocular tumor.

References (20)

There are more references available in the full text version of this article.

Cited by (13)

  • MRI and dual-energy CT fusion anatomic imaging in Ru-106 ophthalmic brachytherapy

    2021, Brachytherapy
    Citation Excerpt :

    A variety of methods have so far been used to accurately locate the tumor intraoperatively and thus accurately position the plaque over the tumor with adequate tumor-free margins around it and decide whether a temporary muscle insertion extirpation may be necessary. Such methods include indirect fundoscopy with or without scleral depression, transpupillary or transcleral transillumination (6), two- and three-dimensional intraoperative ultrasonography (7) or plaque-mounted light-emitting diode illumination (8,9). The detection of the so-called Cerenkov luminescence, a weak light emitted through the interaction of electrons with tissues, has also been proposed (10).

  • Plaque radiotherapy for juxtapapillary choroidal melanoma: Tumor control in 650 consecutive cases

    2011, Ophthalmology
    Citation Excerpt :

    The cases described in the current series all underwent careful localization with intraoperative indirect ophthalmoscopy for secure plaque placement. A variety of intraoperative techniques have been devised to assist localization, such as methods of ultrasound or plaque-mounted transillumination.17–19 In this report, Kaplan-Meier analysis disclosed local tumor recurrence of 14% at 5 years and 21% at 10 years.

  • The American Brachytherapy Society recommendations for brachytherapy of uveal melanomas

    2003, International Journal of Radiation Oncology Biology Physics
  • Plaque radiation therapy for malignant melanoma of the iris and ciliary body

    2001, American Journal of Ophthalmology
    Citation Excerpt :

    In such cases, the posterior margin of the ciliary body band was used as the posterior tumor margin. Because of their anterior location, these cases were poor candidates for three-dimensional ultrasound and diode-light localization techniques.31,32,34 All patients received one plaque radiation that started at insertion and continued until the prescribed dose was delivered to the tumor apex (defined as the point of deepest intraocular tumor extension after dilation).23

View all citing articles on Scopus

Supported in part by The EyeCare Foundation, Inc., New York City.

1

The authors have no proprietary interest in the device described in this study.

View full text