Measurement of Lung Density by Computed Tomography

Implication for Radiotherapy

Ehiichi Kohda, Naoyuki Shigematsu

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

In order to achieve practical application for the treatment planning of radiotherapy, lung density was assessed by means of CT. Cork phantoms were measured 360 times to test the reliability of CT densitometry. Densities were corrected by the CT value of pure water measured at the same time. The mean value of cork phantoms as measured by CT was 0.287±0.11g/cm3, the true value of which was 0.320g/cm3. These errors were within an allowable limit for radiotherapy. Lung density was studied in 50 patients with a mean age of 50 years, ranging from 46 to 76. The values obtained of the upper, middle, and lower lung were 0.123±0.46 g/cm3, 0.121±0.033, and 0.154±0.057 g/cm3 during inspiration and were 0.215±0.058 g/cm3, 0.228±0.066, and 0.260±0.078g/cm3 during expiration, respectively. The dorsal, central, and ventral portions of the lung were measured simultaneously with a patient on supine position. In order to hold the variation of radiation dose within 2%, the variation must be kept within 30 HU of CT value. As for the upper lung, the difference of which between both subjects and sites was smallest during inspiration in this results, that was 20%; the difference of 60 HU CT value existed between the dorsal and ventral lungs. Variations in CT number between subjects were more than 60 HU in one third of this series. Before starting radiotherapy to the lung field, lung densitometry is warranted in order to irradiate the exact dose.

Original languageEnglish
Pages (from-to)454-463
Number of pages10
JournalThe Keio journal of medicine
Volume38
Issue number4
DOIs
Publication statusPublished - 1989

Fingerprint

Radiotherapy
Tomography
Lung
Densitometry
Supine Position
Radiation
Water

Keywords

  • CT
  • lung density
  • radiotherapy

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Measurement of Lung Density by Computed Tomography : Implication for Radiotherapy. / Kohda, Ehiichi; Shigematsu, Naoyuki.

In: The Keio journal of medicine, Vol. 38, No. 4, 1989, p. 454-463.

Research output: Contribution to journalArticle

@article{28f4db0f0cbd4aaea60b3da5cb7c0b5b,
title = "Measurement of Lung Density by Computed Tomography: Implication for Radiotherapy",
abstract = "In order to achieve practical application for the treatment planning of radiotherapy, lung density was assessed by means of CT. Cork phantoms were measured 360 times to test the reliability of CT densitometry. Densities were corrected by the CT value of pure water measured at the same time. The mean value of cork phantoms as measured by CT was 0.287±0.11g/cm3, the true value of which was 0.320g/cm3. These errors were within an allowable limit for radiotherapy. Lung density was studied in 50 patients with a mean age of 50 years, ranging from 46 to 76. The values obtained of the upper, middle, and lower lung were 0.123±0.46 g/cm3, 0.121±0.033, and 0.154±0.057 g/cm3 during inspiration and were 0.215±0.058 g/cm3, 0.228±0.066, and 0.260±0.078g/cm3 during expiration, respectively. The dorsal, central, and ventral portions of the lung were measured simultaneously with a patient on supine position. In order to hold the variation of radiation dose within 2{\%}, the variation must be kept within 30 HU of CT value. As for the upper lung, the difference of which between both subjects and sites was smallest during inspiration in this results, that was 20{\%}; the difference of 60 HU CT value existed between the dorsal and ventral lungs. Variations in CT number between subjects were more than 60 HU in one third of this series. Before starting radiotherapy to the lung field, lung densitometry is warranted in order to irradiate the exact dose.",
keywords = "CT, lung density, radiotherapy",
author = "Ehiichi Kohda and Naoyuki Shigematsu",
year = "1989",
doi = "10.2302/kjm.38.454",
language = "English",
volume = "38",
pages = "454--463",
journal = "Keio Journal of Medicine",
issn = "0022-9717",
publisher = "Keio University School of Medicine",
number = "4",

}

TY - JOUR

T1 - Measurement of Lung Density by Computed Tomography

T2 - Implication for Radiotherapy

AU - Kohda, Ehiichi

AU - Shigematsu, Naoyuki

PY - 1989

Y1 - 1989

N2 - In order to achieve practical application for the treatment planning of radiotherapy, lung density was assessed by means of CT. Cork phantoms were measured 360 times to test the reliability of CT densitometry. Densities were corrected by the CT value of pure water measured at the same time. The mean value of cork phantoms as measured by CT was 0.287±0.11g/cm3, the true value of which was 0.320g/cm3. These errors were within an allowable limit for radiotherapy. Lung density was studied in 50 patients with a mean age of 50 years, ranging from 46 to 76. The values obtained of the upper, middle, and lower lung were 0.123±0.46 g/cm3, 0.121±0.033, and 0.154±0.057 g/cm3 during inspiration and were 0.215±0.058 g/cm3, 0.228±0.066, and 0.260±0.078g/cm3 during expiration, respectively. The dorsal, central, and ventral portions of the lung were measured simultaneously with a patient on supine position. In order to hold the variation of radiation dose within 2%, the variation must be kept within 30 HU of CT value. As for the upper lung, the difference of which between both subjects and sites was smallest during inspiration in this results, that was 20%; the difference of 60 HU CT value existed between the dorsal and ventral lungs. Variations in CT number between subjects were more than 60 HU in one third of this series. Before starting radiotherapy to the lung field, lung densitometry is warranted in order to irradiate the exact dose.

AB - In order to achieve practical application for the treatment planning of radiotherapy, lung density was assessed by means of CT. Cork phantoms were measured 360 times to test the reliability of CT densitometry. Densities were corrected by the CT value of pure water measured at the same time. The mean value of cork phantoms as measured by CT was 0.287±0.11g/cm3, the true value of which was 0.320g/cm3. These errors were within an allowable limit for radiotherapy. Lung density was studied in 50 patients with a mean age of 50 years, ranging from 46 to 76. The values obtained of the upper, middle, and lower lung were 0.123±0.46 g/cm3, 0.121±0.033, and 0.154±0.057 g/cm3 during inspiration and were 0.215±0.058 g/cm3, 0.228±0.066, and 0.260±0.078g/cm3 during expiration, respectively. The dorsal, central, and ventral portions of the lung were measured simultaneously with a patient on supine position. In order to hold the variation of radiation dose within 2%, the variation must be kept within 30 HU of CT value. As for the upper lung, the difference of which between both subjects and sites was smallest during inspiration in this results, that was 20%; the difference of 60 HU CT value existed between the dorsal and ventral lungs. Variations in CT number between subjects were more than 60 HU in one third of this series. Before starting radiotherapy to the lung field, lung densitometry is warranted in order to irradiate the exact dose.

KW - CT

KW - lung density

KW - radiotherapy

UR - http://www.scopus.com/inward/record.url?scp=0024825892&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0024825892&partnerID=8YFLogxK

U2 - 10.2302/kjm.38.454

DO - 10.2302/kjm.38.454

M3 - Article

VL - 38

SP - 454

EP - 463

JO - Keio Journal of Medicine

JF - Keio Journal of Medicine

SN - 0022-9717

IS - 4

ER -