• Journal of radiological science and technology
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• v.44 no.5
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• pp.435-441
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• 2021

The purpose of this study was to evaluate the quality of images and to quantitatively measure and analyze the dose of scattered ray to the organs, which were highly sensitive to radiation according to the use of cylinder cone in mastoid process radiography. When the cylinder cone was not used, the SID was 100cm and the field size was 24 × 36 cm(864 cm²). When using the cylinder cone which was a circle, the SID was 70 cm, the radius was 10.5 cm and field size was 86.59 cm². As a result of the study, SNR of the image quality evaluation was measured to be 2.58 for Law method and 3.90 for Stenver's method when not using cylinder cone, and 2.87 for Law method and 14.67 for Stenver's method when using cylinder cone. CNR was measured to be 0.03 for Law method and 0.04 for Stenver's method when cylinder cone was not used, and 0.04 for Law method and 0.05 for Stenver's method when using cylinder cone. When the cylinder cone was not used, the scattered ray dose was measured to be 0.10 mGy in the right eyeball, 0.30 mGy in the left eyeball, 2.02 mGy in the parotid gland, and 0.29 mGy in the thyroid gland for Law method and to be 0.03 mGy in the right eyeball, 0.12 mGy in the left eyeball, 1.43 mGy in the parotid gland, and 0.09 mGy in the thyroid gland for Stenver's method. When the cylinder cone was used, the scattered ray dose was measured to be 0.05 mGy in the right eyeball, 0.03 mGy in the left eyeball and the parotid and thyroid gland were below the measurable values for Law method and all areas were below the measurable values for Stenver's method. This was found to be statistically significant(p<0.000).

• Proceedings of the KOR-BRONCHOESO Conference
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• 1981.05a
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• pp.40.1-40
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• 1981

The cholesteatoma is usually associated with chronic purulent otitis media and destroys the surrounding structures and may cause dangerous complications. The cholesteatoma with a positive fistula sign may be observed occasionally, if a softened area is formed in the bony capsule over a semicircular canal which exposed the membranous structure of the canal. Recently, the authors have experienced a case of cholesteatoma combined with labyrin thine fistula in a 22-year old male patient. We present this case with a brief review of the literatures.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1983.05a
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• pp.17.4-17
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• 1983

According to Teed, the first report of oseoma in the literature was by Veiga in 1586. There was no satisfactory explanation of its etiology. True osteomas may occur in the mastoid and temporal bone, but they are relatively rare. These tumors are benign, slow growing and composed predominantly of mature bone. Treatment is indicated for symptomatic osteoma. The authors experienced a case of osteoma of the temporal bone which had revealed a progressive posterior auriular swelling, obstructed bony ear canal, chronic ear discharge and hearing loss for about 18 yrs in right side.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1976.06a
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• pp.86.3-86
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• 1976

The external ear canal is a rare site for development of squamous cell carcinoma which is usually in the advanced state of invasion by the time the diagnosis is made. Recently the authors experienced squamous cell carcinoma of the external ear canal which was treated with wide excision of the external ear canal and radical mastoidectomy followed by post-operative radiotherapy.

• The Journal of the Acoustical Society of Korea
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• v.32 no.5
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• pp.423-429
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• 2013

The present study aimed to find the most sensitive placement of the skull to perceive speech through the bone vibrator in various protection methods while being exposed to noise. Twenty young normal-hearing adults (10 male and 10 female) participated in the study. As stimulus, Korean spondee words were presented via one of five skull locations (i.e., jaw angle, condyle, temple, mastoid, and vertex), while the participants wore one of four protection methods (i.e., ear form, ear plug, ear muff, and ear form and muff together) against white noise in one of four noise directions (i.e., 0, 90, 180, 270 degrees). The results showed: 1) there was a significant difference among the five skull locations with condyle being the most sensitive placement; 2) there was a significant difference among the four protection methods, with the ear form plus ear muff condition (or dual protection) providing the lowest threshold; 3) when exposed to noise from 90 degrees, the significantly lowest threshold was found; 4) there was no significant difference in results by gender. The pattern of results suggests that the communicative condition via the condyle bone conduction and the dual protection of the air conduction under any noise direction might be ideal for preventing noise-induced hearing loss, although further studies should be undertaken in this area.