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Pilot study of the delivery of microcollimated pars plana external beam radiation in porcine eyes: 270-day analysis.

Singh RP, Shusterman EM, Moshfeghi D, Danis R, Gertner M - J Ophthalmol (2012)

Bottom Line: Conclusion.The X-ray delivery system precisely targets the porcine retina in vivo with little effect on surrounding structures.No ophthalmic or intracranial adverse effects were noted at clinically relevant doses at 270 days following radiation delivery.

View Article: PubMed Central - PubMed

Affiliation: Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.

ABSTRACT
Objective. To determine the dose response and toxicity threshold of micro-collimated X-rays delivered to porcine maculae by a stereotactic radiosurgical system after 270 days. Methods. Twelve eyes of six Yucatan mini-swine were randomized to receive up to 90 Gy to the retina, using an office-based trans-pars plana delivery system. To determine the safety profile of this radiation delivery, ophthalmic examination, fundus photography, fluorescein angiography (FA), and spectral domain optical coherence tomography (SD-OCT) were obtained at multiple time points up to 270 days post treatment. Results. No abnormalities were noted on external examination. Cataracts were noted in 4 of 12 eyes. Dose and time-dependent changes were noted on fundus examination, FA, ICG and SD-OCT. No significant abnormalities were seen in the control, 16 Gy or 24 Gy groups using any modality. Histopathology revealed a dose response effect with no discernable lesions in the 16 Gy group. Conclusion. The X-ray delivery system precisely targets the porcine retina in vivo with little effect on surrounding structures. No ophthalmic or intracranial adverse effects were noted at clinically relevant doses at 270 days following radiation delivery.

No MeSH data available.


Related in: MedlinePlus

(a) Nuclear cataract found in the 0 Gy animal at day 205. At day 270, no significant worsening was noted. (b) and (c) Cortical lens changes seen in the 90 Gy animal at day 270 by slit lamp examination and by external ocular photography.
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fig2: (a) Nuclear cataract found in the 0 Gy animal at day 205. At day 270, no significant worsening was noted. (b) and (c) Cortical lens changes seen in the 90 Gy animal at day 270 by slit lamp examination and by external ocular photography.

Mentions: Three of the twelve eyes developed nuclear cataracts at day 210 or later. These eyes spanned the gamut of treatment groups, receiving 90 Gy, 16 Gy, and no treatment. One additional eye developed a focal, cortical cataract with 60 Gy treatment. Photos of the cataracts are shown in Figures 2(a)–2(c). While cataracts were detected at the 60 and 90 Gy radiation doses, as well as a 16 Gy eye, a cataract was also present in a control eye, suggesting that the cataracts in the zero and 16 Gy groups may have been age-related. The cataracts noted at the 60 and 90 Gy doses appeared to be relatively more proximate to the X-ray beam paths, located along the nasoventral aspect of the eye, while the cataracts seen at the control and 16 Gy doses seemed to be more central, further suggesting an etiology other than radiation.


Pilot study of the delivery of microcollimated pars plana external beam radiation in porcine eyes: 270-day analysis.

Singh RP, Shusterman EM, Moshfeghi D, Danis R, Gertner M - J Ophthalmol (2012)

(a) Nuclear cataract found in the 0 Gy animal at day 205. At day 270, no significant worsening was noted. (b) and (c) Cortical lens changes seen in the 90 Gy animal at day 270 by slit lamp examination and by external ocular photography.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3401568&req=5

fig2: (a) Nuclear cataract found in the 0 Gy animal at day 205. At day 270, no significant worsening was noted. (b) and (c) Cortical lens changes seen in the 90 Gy animal at day 270 by slit lamp examination and by external ocular photography.
Mentions: Three of the twelve eyes developed nuclear cataracts at day 210 or later. These eyes spanned the gamut of treatment groups, receiving 90 Gy, 16 Gy, and no treatment. One additional eye developed a focal, cortical cataract with 60 Gy treatment. Photos of the cataracts are shown in Figures 2(a)–2(c). While cataracts were detected at the 60 and 90 Gy radiation doses, as well as a 16 Gy eye, a cataract was also present in a control eye, suggesting that the cataracts in the zero and 16 Gy groups may have been age-related. The cataracts noted at the 60 and 90 Gy doses appeared to be relatively more proximate to the X-ray beam paths, located along the nasoventral aspect of the eye, while the cataracts seen at the control and 16 Gy doses seemed to be more central, further suggesting an etiology other than radiation.

Bottom Line: Conclusion.The X-ray delivery system precisely targets the porcine retina in vivo with little effect on surrounding structures.No ophthalmic or intracranial adverse effects were noted at clinically relevant doses at 270 days following radiation delivery.

View Article: PubMed Central - PubMed

Affiliation: Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.

ABSTRACT
Objective. To determine the dose response and toxicity threshold of micro-collimated X-rays delivered to porcine maculae by a stereotactic radiosurgical system after 270 days. Methods. Twelve eyes of six Yucatan mini-swine were randomized to receive up to 90 Gy to the retina, using an office-based trans-pars plana delivery system. To determine the safety profile of this radiation delivery, ophthalmic examination, fundus photography, fluorescein angiography (FA), and spectral domain optical coherence tomography (SD-OCT) were obtained at multiple time points up to 270 days post treatment. Results. No abnormalities were noted on external examination. Cataracts were noted in 4 of 12 eyes. Dose and time-dependent changes were noted on fundus examination, FA, ICG and SD-OCT. No significant abnormalities were seen in the control, 16 Gy or 24 Gy groups using any modality. Histopathology revealed a dose response effect with no discernable lesions in the 16 Gy group. Conclusion. The X-ray delivery system precisely targets the porcine retina in vivo with little effect on surrounding structures. No ophthalmic or intracranial adverse effects were noted at clinically relevant doses at 270 days following radiation delivery.

No MeSH data available.


Related in: MedlinePlus