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Individualized eye shields for use in electron beam therapy as well as low-energy photon irradiation
Inf. J. Rodimion Oncdogy Bid. Phys.. Vol. 6. pp. 519-521 6 Pergamon Press Ltd.. 1980. Printed in the U.S.A.
0
036(r3016/80/04051943$02.00/0
Technical Innovations and Notes INDIVIDUALIZED EYE SHIELDS FOR USE IN ELECTRON BEAM THERAPY AS WELL AS LOW-ENERGY PHOTON IRRADIATION SUCHA
0. ASBELL,
JOHN SIU, R. T. T.,f’ DAVID and LUTHER W. BRADY, M.D.8
M.D.,*
A.
LIGHTFOOT,
M.A.,$
*Chairman, Department of Radiation Therapy, Albert Enstein Medical Center, Northern Division, York and Tabor Roads, Philadelphia, Pennsylvania 1914l;tMold Room Technician, Department of Radiation Therapy and Nuclear Medicine, Hahnemann Medical College and Hospital, 230 N. Broad Street, Philadephia, Pennsylvania 19102; $Staff Physicist, Department of Radiation Therapy and Nuclear Medicine, Hahnemann Medical College and Hospital 230 N. Broad Street, Philadelphia, Pennsylvania 19102; and §Chairman, Department of Radiation Therapy and Nuclear Medicine, Hahnemann Medical college and Hospital 230 N. Broad Street, Philadelphia. Pennsylvania 19 102 Tkin lead eye shields formed with a rubber hammer over smooth wooden mandril and coated with dental acrylic have been used 01 25 patients undergoing electron beam treatment for mycosis fungoldes or superkial x-ray irradiation with no sig&lcant diflkulties. The shields may be fabricated in less than two hours and exactly fit the contour and size of the eye. Details of the fabrication process and evaluation of the shielding effectiveness are present+% Lead shields, Eye shields Protection from radiation.
INTRODUCTION
cient to fully cover the anterior portion of the globe and eliminated the possibility of shifting. Their reduced weight and tight fit compared to the commercially available shields permitted their use in any treatment position.
When electron beam irradiation was used in the treatment of mycosis fungoides it was found that if external protection eye shields were used, recurrences of the skin growths on the lids were frequent. Therefore, it became customary to use internal eye shields whenever the patient faced the electron beam. Usually several patients were under treatment at the same time, and each required a pair of eye shields. To avoid using the same shield from one patient to the next it was necessary to purchase duplicate eye shields in each size for bilateral use. Because of the expense this incurred and also because of the frequently improper fit, individualized eye shields were fabricated in our department. Initially we utilized lead in l/ 16th inch thickness and coated it with beeswax. However, this was found to be unsatisfactory since the beeswax chipped easily and required re-coating. Therefore, we substituted dental acrylic *for the beeswax and polished it with fine pumice. This yielded a more durable surface that was virtually maintenance free. The size and contour of the shields made were suffi-
METHODS
AND MATERIALS
The eye shields were fabricated as follows: First, the required diameters were determined by measuring from the zygomatic arch to the superior orbital ridge (Fig. 1). Then the hemispherically shaped end of a tool handle of an appropriate diameter was used as a model against which a 1/16th inch thick, 2” x 2” lead square was contoured with a plastic tipped hammer (Fig. 2). After contouring, the lead was cut with shears to a suitable shape (Fig. 3). Next the lead was coated directly on all surfaces with a self-curing dental acrylic (Fig. 4). The edges were trimmed while the acrylic was still flexible taking care to leave an edge bead (Fig. 5). Finally, the shields were polished after the acrylic had hardened to provide smooth inert surfaces (Fig. 6). When inserted under the patient’s eyelids, the shields adequately 12-16 October 1976. Acknowledgemenls-Radiation dose measurements were conducted with the assistance of Edward P. Yeager, Joseph P. Note and Richard Tobin. Our current modification is based on Stanford University, Department of Radiation Therapy’s beeswax covered eye shield model. Reprint requests to: Sucha Asbell, M.D. Accepted for publication 29 October 1979.
*National Keeptone, Naturlyic Acrylic; Quick care, National Keystone Products Co., 2154 Market St, Philadelphia, Pa. 19103 U.S.A. This investigation was supported by Grant Number 2 RIO CA 12252-05 and by Grant Number 3 PO1 CA 14043 awarded by the National Cancer Institute, Department of Health, Education and Welfare. This paper was presented as an exhibit at the Annual Meeting of the American Society of Therapeutic Radiologists, 519
Radiation
Oncology 0 Biology
??Physics
Fig. 1. The required diameters of the eye shields are determined by measuring from the zygomatic arch to the superior orbital ridge.
Fig. 2. A I/ 16” thick 2 x 2” lead square is contoured plastic tipped hammer.
Fig. 3. After contouring suitable shape.
the lead was cut with shears
with a
to a
April
1980, Volume 6, Number
4
Fig. 4. The lead is coated directly acrylic.
Fig. 5. Excess acrylic is trimmed
on all surfaces
with dental
while it is still flexible.
Fig. 6. Hardened acrylic is polished with pumice stone and a soft motor driven brush.
Eye
shields for use in electron beam therapy and low-energy photon irradiation
0 S. 0. ASBELL etal.
521
Table 1. Effectiveness of eye shields per 100 rad unshielded dose
Type of radiation I20 KVP x-rays (1.1 mm Al HVL) 280 KVP x-rays (1.2 mm Cu HVL) 280 KVP x-rays (1.5 mm Cu HVL) 280 KVP x-rays (2.6 mm Cu HVL) 3.6 MeV electrons Fig. 7. Shields inserted under the patient’s eyelids demonstrate adequate coverage of each globe. the globe (Fig. 7). The eye shields were evaluated for their effectiveness in treatments with 120 KVP x-rays, 280 KVP x-rays and 3.6 MeV electrons. The shields were found to be suitable in all cases. Transmission was measured in air with a 2 cm. diameter field and a shield which was positioned midway between the source and the ionization chamber placed 100 cm. from the source. The resultant effect on patient dose, which included both transmission through the shields plus scattered irradiation from other parts of the field, was evaluated by therm0 lumiaiscent dosimetry (TLD) placed in a wax partial globe added to the surface of a radiotherapy phantom.* The simulated treatment for the x-ray beam was a single 6 x 8 cm. anterior field. The simulated treatment for total body electron beam was full-sized multi-directional total skin irradiation in complete sequence. In all cases, the dose without a shield in place was 100 rad.
Measured radiation transmitted through shields (rad)
Measured doses scattered and transmitted through shields (rad)
0.07
6.7
2.6
12.5
3.4
14.5
5.0 NA
15.2 1.6
NA-Not assessed because of technical difficulty.
covered
RESULTS Table scattered *Rando.
AND DISCUSSION
1 shows the measured doses transmitted and utilizing different photon and electron irradia-
tion. Subsequent to their development, these shields have been utilized for patients treated with superficial irradiation or low energy electron beam irradiation whenever the eye has been included in the field of treatment. Since the entire process takes less than 2 hours, fit can be corrected simply by a second fabrication. Close ophthalmological evaluation of some 25 patients to date has failed to show any serious irritation or any evidence of abrasion after fluorescein examination. The materials and manufacture of these eye shields cost less than $2.00 per pair. Hand tools that may be used repeatedly have an initial cost of approximately $10.00. Motor and polishing wheel, costing approximately $100.00, usually can be borrowed from within the hospital. These eye shields, therefore, provide individualized, inexpensive shielding which can be manufactured with little time or effort. They provide protection for those patients who are receiving total body electron beam irradiation in the treatment of mycosis fungoides, and make possible the availability of multiple shields or individualized fit in other therapeutic circumstances as well.
0
036(r3016/80/04051943$02.00/0
Technical Innovations and Notes INDIVIDUALIZED EYE SHIELDS FOR USE IN ELECTRON BEAM THERAPY AS WELL AS LOW-ENERGY PHOTON IRRADIATION SUCHA
0. ASBELL,
JOHN SIU, R. T. T.,f’ DAVID and LUTHER W. BRADY, M.D.8
M.D.,*
A.
LIGHTFOOT,
M.A.,$
*Chairman, Department of Radiation Therapy, Albert Enstein Medical Center, Northern Division, York and Tabor Roads, Philadelphia, Pennsylvania 1914l;tMold Room Technician, Department of Radiation Therapy and Nuclear Medicine, Hahnemann Medical College and Hospital, 230 N. Broad Street, Philadephia, Pennsylvania 19102; $Staff Physicist, Department of Radiation Therapy and Nuclear Medicine, Hahnemann Medical College and Hospital 230 N. Broad Street, Philadelphia, Pennsylvania 19102; and §Chairman, Department of Radiation Therapy and Nuclear Medicine, Hahnemann Medical college and Hospital 230 N. Broad Street, Philadelphia. Pennsylvania 19 102 Tkin lead eye shields formed with a rubber hammer over smooth wooden mandril and coated with dental acrylic have been used 01 25 patients undergoing electron beam treatment for mycosis fungoldes or superkial x-ray irradiation with no sig&lcant diflkulties. The shields may be fabricated in less than two hours and exactly fit the contour and size of the eye. Details of the fabrication process and evaluation of the shielding effectiveness are present+% Lead shields, Eye shields Protection from radiation.
INTRODUCTION
cient to fully cover the anterior portion of the globe and eliminated the possibility of shifting. Their reduced weight and tight fit compared to the commercially available shields permitted their use in any treatment position.
When electron beam irradiation was used in the treatment of mycosis fungoides it was found that if external protection eye shields were used, recurrences of the skin growths on the lids were frequent. Therefore, it became customary to use internal eye shields whenever the patient faced the electron beam. Usually several patients were under treatment at the same time, and each required a pair of eye shields. To avoid using the same shield from one patient to the next it was necessary to purchase duplicate eye shields in each size for bilateral use. Because of the expense this incurred and also because of the frequently improper fit, individualized eye shields were fabricated in our department. Initially we utilized lead in l/ 16th inch thickness and coated it with beeswax. However, this was found to be unsatisfactory since the beeswax chipped easily and required re-coating. Therefore, we substituted dental acrylic *for the beeswax and polished it with fine pumice. This yielded a more durable surface that was virtually maintenance free. The size and contour of the shields made were suffi-
METHODS
AND MATERIALS
The eye shields were fabricated as follows: First, the required diameters were determined by measuring from the zygomatic arch to the superior orbital ridge (Fig. 1). Then the hemispherically shaped end of a tool handle of an appropriate diameter was used as a model against which a 1/16th inch thick, 2” x 2” lead square was contoured with a plastic tipped hammer (Fig. 2). After contouring, the lead was cut with shears to a suitable shape (Fig. 3). Next the lead was coated directly on all surfaces with a self-curing dental acrylic (Fig. 4). The edges were trimmed while the acrylic was still flexible taking care to leave an edge bead (Fig. 5). Finally, the shields were polished after the acrylic had hardened to provide smooth inert surfaces (Fig. 6). When inserted under the patient’s eyelids, the shields adequately 12-16 October 1976. Acknowledgemenls-Radiation dose measurements were conducted with the assistance of Edward P. Yeager, Joseph P. Note and Richard Tobin. Our current modification is based on Stanford University, Department of Radiation Therapy’s beeswax covered eye shield model. Reprint requests to: Sucha Asbell, M.D. Accepted for publication 29 October 1979.
*National Keeptone, Naturlyic Acrylic; Quick care, National Keystone Products Co., 2154 Market St, Philadelphia, Pa. 19103 U.S.A. This investigation was supported by Grant Number 2 RIO CA 12252-05 and by Grant Number 3 PO1 CA 14043 awarded by the National Cancer Institute, Department of Health, Education and Welfare. This paper was presented as an exhibit at the Annual Meeting of the American Society of Therapeutic Radiologists, 519
Radiation
Oncology 0 Biology
??Physics
Fig. 1. The required diameters of the eye shields are determined by measuring from the zygomatic arch to the superior orbital ridge.
Fig. 2. A I/ 16” thick 2 x 2” lead square is contoured plastic tipped hammer.
Fig. 3. After contouring suitable shape.
the lead was cut with shears
with a
to a
April
1980, Volume 6, Number
4
Fig. 4. The lead is coated directly acrylic.
Fig. 5. Excess acrylic is trimmed
on all surfaces
with dental
while it is still flexible.
Fig. 6. Hardened acrylic is polished with pumice stone and a soft motor driven brush.
Eye
shields for use in electron beam therapy and low-energy photon irradiation
0 S. 0. ASBELL etal.
521
Table 1. Effectiveness of eye shields per 100 rad unshielded dose
Type of radiation I20 KVP x-rays (1.1 mm Al HVL) 280 KVP x-rays (1.2 mm Cu HVL) 280 KVP x-rays (1.5 mm Cu HVL) 280 KVP x-rays (2.6 mm Cu HVL) 3.6 MeV electrons Fig. 7. Shields inserted under the patient’s eyelids demonstrate adequate coverage of each globe. the globe (Fig. 7). The eye shields were evaluated for their effectiveness in treatments with 120 KVP x-rays, 280 KVP x-rays and 3.6 MeV electrons. The shields were found to be suitable in all cases. Transmission was measured in air with a 2 cm. diameter field and a shield which was positioned midway between the source and the ionization chamber placed 100 cm. from the source. The resultant effect on patient dose, which included both transmission through the shields plus scattered irradiation from other parts of the field, was evaluated by therm0 lumiaiscent dosimetry (TLD) placed in a wax partial globe added to the surface of a radiotherapy phantom.* The simulated treatment for the x-ray beam was a single 6 x 8 cm. anterior field. The simulated treatment for total body electron beam was full-sized multi-directional total skin irradiation in complete sequence. In all cases, the dose without a shield in place was 100 rad.
Measured radiation transmitted through shields (rad)
Measured doses scattered and transmitted through shields (rad)
0.07
6.7
2.6
12.5
3.4
14.5
5.0 NA
15.2 1.6
NA-Not assessed because of technical difficulty.
covered
RESULTS Table scattered *Rando.
AND DISCUSSION
1 shows the measured doses transmitted and utilizing different photon and electron irradia-
tion. Subsequent to their development, these shields have been utilized for patients treated with superficial irradiation or low energy electron beam irradiation whenever the eye has been included in the field of treatment. Since the entire process takes less than 2 hours, fit can be corrected simply by a second fabrication. Close ophthalmological evaluation of some 25 patients to date has failed to show any serious irritation or any evidence of abrasion after fluorescein examination. The materials and manufacture of these eye shields cost less than $2.00 per pair. Hand tools that may be used repeatedly have an initial cost of approximately $10.00. Motor and polishing wheel, costing approximately $100.00, usually can be borrowed from within the hospital. These eye shields, therefore, provide individualized, inexpensive shielding which can be manufactured with little time or effort. They provide protection for those patients who are receiving total body electron beam irradiation in the treatment of mycosis fungoides, and make possible the availability of multiple shields or individualized fit in other therapeutic circumstances as well.