후안부 방사능성沃度 조사에 관한 연구

Abstract

[한글]

The Studies on Irradiation of the Posterior Ocular Segment With Radioactive Iodine

Ouk Choi, M.D.

Department of Ophthalmology. Department of Pharmacology and Toxicology

Yonsei University School of Medicine Seoul, Korea

(Directed by Drs. Frank W. Newell and W. C. Lee)

A new type of polyethylene envelopes were attached to the sclera of male

pigmented and albino rabbits weighing between 2.5 and 30.kg. The polyethylene

envelope was sutured to the globe at about the equator, then filled with the

previously prepared radioactive iodine of different activities in the different

animals. The effects of this radiation were studied ophthalmoscopically and

histologically at intervals varying from one week to 58 weeks after implantation in

the dosage range from 0.18mc/cm**2 to 20.mc/cm**2.

Polyethylene envelopes are made by means of an aluminum mold at 250°F. Prior to

sealing a 6.0mm, circular disc of eight-ply cellulose blotting material is enclosed

in the envelope. It was found that 0.01cc. of fluid completely saturates the

blotting paper. The envelope is filled by means of a fine No.10 polyethylene tubing

and, when the envelope is filled, the implant is sealed, using a curved hemostat

with flat surfaces heated to 300°F.

Results

Ophthalmoscopic changes : These were noted consistently only in animals in which

the isotope density was 1..5mc/cm**2 or more

In animals receiving 2.0mc/cm**2, initial ophthalnoscopic changes of an

ill-defined grayish-white elevation over the site of implantation were noted at

examination two and three weeks after the procedure. These lesions developed into

well-defined , sharply circumscribed and slightly elevated whitish areas over which

were scattered numerous dark-brown pigmented dots. In the periphery of the area,

choroidal blood vessels were evident. No hemorrhages were noted at any time.

The opthalmoscopic changes in animals receiving 1.5mc/cm**2, were similar but the

initial changes were (1884) not observed until five or six weeks after

implantation.

Consistent ophthalmoscopic changes were not observed in animals receiving

1.0mc/cm**2. Rarely, an ill-defined slightly pale area was noted over the

implantation site seven to nine weeks after the procedure. In animals receiving

0.72mc/cm**2 or less ophthalmoscopic changes did not occur.

Histologic changes : There were no histologic lesions demonstrated in animals

receiving between 0.18 and 0.72mc/cm**2 of radiation.

Of animals treated with 0.90 to 1.0mc/cm**2 of radiation, histologic changes

occurred in about 1/3. The affected animals showed thinning of the choroid adjacent

to the envelope and no changes in the pigment epithelium. The external limiting

membrane and outer nuclear layer in the corresponding area were thinned and there

was a decrease in cell population.

In the animals killed at 58 weeks, in addition to the changes just described, the

pigment epithelium was flattened and there was rarefaction of the outer plexiform

and inner nuclear layers.

In all animals receiving an application of 1.50-2.0mc/cm**2, definite

ophthalmoscopic and histologic changes occurred.

After one week the layer of rods and cones was destroyed and there was thinning

of the corresponding outer nuclear layer. The remainder of the eye appeared normal.

After 12 to 26 weeks the choroid was nearly entirely destroyed with few or no

blood vessels remaining. The pigments epithelium was thinned and the remaining

cells were flat and degenerated and of a spindle rather than cuboidal shape. In

some areas there was migration of the pigment epithelium into the region of the

degenerated retina.

After eight weeks, the remaining retina consisted of a rarefled inner nuclear

layer and a few ganglion cells. Lens opacities were bot observed and the retina on

the side of the eye directly opposite to the site of implantation was not affected.

Summary and Conclusion

1. Rabbit eyes treated with iodine instilled in a new type of polyethylene

envelope containing blotting paper. The envelope was sutured to the sclera prior to

instillation of the isotope.

2. No ophthalmoscopic or histologic lesions were observed with concentration of

0.18 to 0.72mc/cm**2. A concentration of 0.9-1.0mc/cm**2, resulted, in some

animals, in a retinal lesion limited largely to the rod layer, with minor injury to

the corresponding external limiting membrane and outer nuclear layer. A

concentration of 1.5-2.0mc/cm**2 destroyed the choroid and retina, with a few

ganglion cells and inner nuclear layer cells persisting. Damage developed more

slowly in animals receiving the lower dosage but the end-results were similar.

3. Cataract and the other radiation injury did not develop in the limited period

of observation, which varied to a maximum of 58 weeks.

4. It is believed that focal ionizing radiation of intraocular tumors is

feasible, using the polyethylene envelope and absorbent layer in a minimal dosage

of 2.0mc/cm**2 of iodine**131 .

[영문]

A new type of polyethylene envelopes were attached to the sclera of male pigmented and albino rabbits weighing between 2.5 and 30.kg. The polyethylene envelope was sutured to the globe at about the equator, then filled with the previously prepared radioactive iodine of different activities in the different

animals. The effects of this radiation were studied ophthalmoscopically and histologically at intervals varying from one week to 58 weeks after implantation in the dosage range from 0.18mc/cm**2 to 20.mc/cm**2.

Polyethylene envelopes are made by means of an aluminum mold at 250°F. Prior to sealing a 6.0mm, circular disc of eight-ply cellulose blotting material is enclosed in the envelope. It was found that 0.01cc. of fluid completely saturates the blotting paper. The envelope is filled by means of a fine No.10 polyethylene tubing and, when the envelope is filled, the implant is sealed, using a curved hemostat with flat surfaces heated to 300°F.

Results

Ophthalmoscopic changes : These were noted consistently only in animals in which the isotope density was 1..5mc/cm**2 or more

In animals receiving 2.0mc/cm**2, initial ophthalnoscopic changes of an ill-defined grayish-white elevation over the site of implantation were noted at examination two and three weeks after the procedure. These lesions developed into well-defined , sharply circumscribed and slightly elevated whitish areas over which were scattered numerous dark-brown pigmented dots. In the periphery of the area, choroidal blood vessels were evident. No hemorrhages were noted at any time.

The opthalmoscopic changes in animals receiving 1.5mc/cm**2, were similar but the initial changes were (1884) not observed until five or six weeks after implantation.

Consistent ophthalmoscopic changes were not observed in animals receiving 1.0mc/cm**2. Rarely, an ill-defined slightly pale area was noted over the implantation site seven to nine weeks after the procedure. In animals receiving 0.72mc/cm**2 or less ophthalmoscopic changes did not occur.

Histologic changes : There were no histologic lesions demonstrated in animals receiving between 0.18 and 0.72mc/cm**2 of radiation.

Of animals treated with 0.90 to 1.0mc/cm**2 of radiation, histologic changes occurred in about 1/3. The affected animals showed thinning of the choroid adjacent to the envelope and no changes in the pigment epithelium. The external limiting

membrane and outer nuclear layer in the corresponding area were thinned and there was a decrease in cell population.

In the animals killed at 58 weeks, in addition to the changes just described, the pigment epithelium was flattened and there was rarefaction of the outer plexiform and inner nuclear layers.

In all animals receiving an application of 1.50-2.0mc/cm**2, definite ophthalmoscopic and histologic changes occurred.

After one week the layer of rods and cones was destroyed and there was thinning of the corresponding outer nuclear layer. The remainder of the eye appeared normal.

After 12 to 26 weeks the choroid was nearly entirely destroyed with few or no blood vessels remaining. The pigments epithelium was thinned and the remaining cells were flat and degenerated and of a spindle rather than cuboidal shape. In some areas there was migration of the pigment epithelium into the region of the

degenerated retina.

After eight weeks, the remaining retina consisted of a rarefled inner nuclear layer and a few ganglion cells. Lens opacities were bot observed and the retina on the side of the eye directly opposite to the site of implantation was not affected.

Summary and Conclusion

1. Rabbit eyes treated with iodine instilled in a new type of polyethylene envelope containing blotting paper. The envelope was sutured to the sclera prior to instillation of the isotope.

2. No ophthalmoscopic or histologic lesions were observed with concentration of 0.18 to 0.72mc/cm**2. A concentration of 0.9-1.0mc/cm**2, resulted, in some animals, in a retinal lesion limited largely to the rod layer, with minor injury to

the corresponding external limiting membrane and outer nuclear layer. A concentration of 1.5-2.0mc/cm**2 destroyed the choroid and retina, with a few ganglion cells and inner nuclear layer cells persisting. Damage developed more slowly in animals receiving the lower dosage but the end-results were similar.

3. Cataract and the other radiation injury did not develop in the limited period of observation, which varied to a maximum of 58 weeks.

4. It is believed that focal ionizing radiation of intraocular tumors is feasible, using the polyethylene envelope and absorbent layer in a minimal dosage of 2.0mc/cm**2 of iodine**131 .