RADIOISOTOPES

Evaluation of Estimation Method of X-ray Spectral Distribution by Attenuation Data

Shoji TOMINAGA, Yasuyuki IBARAKI, Shojiro NAGATA

1980 Volume 29 Issue 5 Pages 215-220
Published: May 15, 1980
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_215

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This paper describes a method for estimating spectral distributions from X-ray attenuation data obtained by inserting metal filters in the beam. First, the principle of the estimation method is briefly outlined. The spectral distribution is approximated by a histogram with an appropriate number of cells whose heights are estimated by recursive algorithm. The algorithm is based on a gradient method that seeks the minimum of a least-square criterion function.
Next, the following two problems to which special attention should be paid in practical applications are discussed: 1) appearance of discontinuity in estimated distribution; and 2) termination criterion of iterative computation. The problem 1) is investigated theoretically and the improved algorithm is devised. Computer simulation is performed for the problem 2), and a proper termination criterion based on the decreasing curve of the least-square criterion function is given. The validity of estimation results is illustrated about the spectral distribution of 140 kV constant potential X-ray source.

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Activation Analysis of Mercury in Head Hair of Dentists

Kunikazu NOGUCHI, Masami SHIMIZU, Kazunari MORIWAKI, Kenichi JINNOUCHI ...

1980 Volume 29 Issue 5 Pages 221-226
Published: May 15, 1980
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_221

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Mercury contents in head hair of 58 dentists, working at the hospital of Nihon University School of Dentistry, were determined using neutron activation analysis. The values ranged from 2.47 ppm to 13.7 ppm. The frequency distribution of the mercury contents increased steeply at about 2 ppm to the maximum of 4-5 ppm, and decreased to about 11 ppm, its distribution pattern followed a log-normal one with a median of 5.46 ppm.
The dentists were divided into two groups and the mercury contents in head hair of them were compared with each other. The arithmetic and geometric means of the values for dentists who handled amalgam in dental practice were 5.66 ppm (SD±1.80) and 5.40 ppm (SD^×_÷1.36), while those for the dentists who did not handle amalgam in dental practice were 5.96 ppm (SD±2.82) and 5.38 ppm (SD^×_÷1.59) . The values of them agreed well with each other. The arithmetic mean for all dentists was 5.79 ppm (SD±2.28) and the geometric mean of them was 5.40 ppm (SD^×_÷1.46) . They were much lower than the values reported by Suzuki, Miyazawa or Sai-renji, et al, in the past year, and they agreed well to those for normal Japanese men with the same age. Therefore it is concluded that proper mercury handling might be established in the dental office.

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Gamma Dose Estimation to the Gastric Wall after Administration of a Capsule Containing a Large Dose of ¹³¹I

Hiyoshimaru OYAMADA, Hiroyoshi FUKUKITA, Kiyomitsu KAWACHI, Hideo KAWA ...

1980 Volume 29 Issue 5 Pages 227-232
Published: May 15, 1980
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_227

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Gamma dose to the gastric wall from a capsule containing 1.85 GBq (50 mCi) of¹³¹I was estimated in 6 patients who had received total thyroidectomy for thyroid carcinoma some years before. The tests were done with a 37 MBq (1mCi) capsule each in 5 patients and with a 185 MBq (5 mCi) capsule in one patient. All the patients were requested to fast in the morning. The capsule was given with a glass of water (200ml) . Then, the patient kept supine position under the scintillation camera for a period of one hour except one patient on whom the test was suspended at 30 minutes because of early clearance of the radioactivity from the stomach. In one of 5 patients who were tested for a period of one hour, serial scinticamera images showed almost no movement and minimum dissolution of the capsule. The remaining 4 patients show-ed slight to moderate movements of the capsules with a variety of dissolution speeds.
Data processings were done by Scintipac-1200. The estimated doses at the distance of 0.5 cm from the source were 3.820, 2.074, 1.445, 1.154 and 1.462 grays (382.0, 207.4, 144.5, 115.4 and 146.2 rads) per initial one hour and 375 mGy (37.5 rad) per initial 30 minutes, respectively.
From these data, it is thought to be wise to advise the patient to rotate or shake the body on bed occasionally after swallowing the capsules containing a large dose of¹³¹I for the treatment of thyroid cancer. It is also desirable to recommend the patient to walk around even though the controlled patient's room is small. Additional water may be also meaningful to avoid unnecessary irradiation to the gastric wall.

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A Gas Replacement Monitor for β-ray Cameras

Takahiko AOYAMA, Shigeaki MATSUNAGA, Tamaki WATANABE

1980 Volume 29 Issue 5 Pages 233-235
Published: May 15, 1980
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_233

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Radon Measurement with a Lucas-Type Counter

—Application to radium determination in natural watert—

Kenji YAMAZAKI, Kazunori FURUYAMA, Koh SAKAMOTO, Masanobu SAKANOUE

1980 Volume 29 Issue 5 Pages 236-239
Published: May 15, 1980
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_236

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²⁰¹Tl-Myocardial Perfusion Image by Single Photon Emission CT

Akira TADA, Toshio MAEDA, Hiroshi MATSUDA, Hisashi BUNKO, Norihisa TON ...

1980 Volume 29 Issue 5 Pages 240-242
Published: May 15, 1980
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_240

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Clinical Evaluation of Hepatobiliary Scintigraphy with ^99mTc-p-butyl IDA.

Takeshi IMOTO, Yoshihiko OSHIUMI, Itsuma KAMOI, Yuichi ICHIYA, Makoto ...

1980 Volume 29 Issue 5 Pages 243-246
Published: May 15, 1980
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_243

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Evaluation of Adrenal Diseases with a New Adrenal-scanning Agent, 6-methyl-⁷⁵Se-selenome-thyl-19-norcholest-5 (10) -en-3β-ol

Hikaru SETO, Ryusuke FUTATSUYA, Masao KAKISHITA, Hirofumi MORI, Kinich ...

1980 Volume 29 Issue 5 Pages 247-249
Published: May 15, 1980
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_247

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⁶⁷Ga Binding Substances in the Tumor and Liver Tissues

Atsushi ANDO, Itsuko ANDO, Tatsunosuke HIRAKI, Masazumi TAKESHITA, Son ...

1980 Volume 29 Issue 5 Pages 250-251
Published: May 15, 1980
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_250

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The Application of Radioimmunoassay for Virus and Anticancer Drugs

Shigeshi TOYOSHIMA

1980 Volume 29 Issue 5 Pages 252-260
Published: May 15, 1980
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_252

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[title in Japanese]

1980 Volume 29 Issue 5 Pages A2025-A80
Published: May 15, 1980
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.29.5_A2025

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