Radiation dose reduction of unenhanced CT limited to the kidneys for follow-up of patients with known nephrolithiasis without symptoms

Research output: Contribution to journalArticle

Abstract

OBJECTIVE. The purpose of this study is to identify the landmarks and associated radiation dose reduction for limited CT of the kidneys of patients requiring follow-up for known nephrolithiasis. MATERIALS AND METHODS. This retrospective study included all adult patients who underwent CT examination type “CT abdomen + pelvis renal stone” at our institution during 2017. Several exclusion criteria were identified, including scoliosis and congenital renal abnormalities. A total of 299 patients met the inclusion and exclusion criteria. The radiation dose and z-axis length associated with the original CT scan were recorded. The upper and lower limits of both kidneys in relation to the vertebral body endplates were recorded, to determine the z-axis length for a CT scan limited to the kidneys. A commercially available radiation dose analytics software package was used to provide estimates of whole-body– and individual organ–equivalent doses for the original CT scan and the limited range CT scan. RESULTS. The superior endplate of T11 and the inferior endplate of L5 are landmarks that will include both kidneys on almost all scans. A limited z-axis range leads to a mean scan length reduction of 50%. The whole-body mean effective dose is reduced by 41.5%, and the doses to the breast and the gonadal and bladder organs are reduced by 71.7%, 73.8%, and 81.8%, respectively. CONCLUSION. For patients without symptoms who are undergoing CT surveillance to evaluate renal calculi growth, new stone formation, or both, a limited-range scan extending from the superior endplate of T11 to the inferior endplate of L5 results in a significant reduction in radiation dose.

Original languageEnglish (US)
Pages (from-to)123-126
Number of pages4
JournalAmerican Journal of Roentgenology
Volume213
Issue number1
DOIs
StatePublished - Jan 1 2019

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Nephrolithiasis
Radiation
Kidney
Kidney Pelvis
Kidney Calculi
Scoliosis
Abdomen
Urinary Bladder
Breast
Software
Retrospective Studies
Growth

Keywords

  • CT
  • Dose
  • Kidney
  • Nephrolithiasis
  • Stone

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

@article{7037be7b73894b52925c73b501c33eb7,
title = "Radiation dose reduction of unenhanced CT limited to the kidneys for follow-up of patients with known nephrolithiasis without symptoms",
abstract = "OBJECTIVE. The purpose of this study is to identify the landmarks and associated radiation dose reduction for limited CT of the kidneys of patients requiring follow-up for known nephrolithiasis. MATERIALS AND METHODS. This retrospective study included all adult patients who underwent CT examination type “CT abdomen + pelvis renal stone” at our institution during 2017. Several exclusion criteria were identified, including scoliosis and congenital renal abnormalities. A total of 299 patients met the inclusion and exclusion criteria. The radiation dose and z-axis length associated with the original CT scan were recorded. The upper and lower limits of both kidneys in relation to the vertebral body endplates were recorded, to determine the z-axis length for a CT scan limited to the kidneys. A commercially available radiation dose analytics software package was used to provide estimates of whole-body– and individual organ–equivalent doses for the original CT scan and the limited range CT scan. RESULTS. The superior endplate of T11 and the inferior endplate of L5 are landmarks that will include both kidneys on almost all scans. A limited z-axis range leads to a mean scan length reduction of 50{\%}. The whole-body mean effective dose is reduced by 41.5{\%}, and the doses to the breast and the gonadal and bladder organs are reduced by 71.7{\%}, 73.8{\%}, and 81.8{\%}, respectively. CONCLUSION. For patients without symptoms who are undergoing CT surveillance to evaluate renal calculi growth, new stone formation, or both, a limited-range scan extending from the superior endplate of T11 to the inferior endplate of L5 results in a significant reduction in radiation dose.",
keywords = "CT, Dose, Kidney, Nephrolithiasis, Stone",
author = "Ghaneh Fananapazir and Liliya Klimkiv and Noah Canvasser and Ramit Lamba and Loehfelm, {Thomas W} and Corwin, {Michael T}",
year = "2019",
month = "1",
day = "1",
doi = "10.2214/AJR.18.20805",
language = "English (US)",
volume = "213",
pages = "123--126",
journal = "American Journal of Roentgenology",
issn = "0361-803X",
publisher = "American Roentgen Ray Society",
number = "1",

}

TY - JOUR

T1 - Radiation dose reduction of unenhanced CT limited to the kidneys for follow-up of patients with known nephrolithiasis without symptoms

AU - Fananapazir, Ghaneh

AU - Klimkiv, Liliya

AU - Canvasser, Noah

AU - Lamba, Ramit

AU - Loehfelm, Thomas W

AU - Corwin, Michael T

PY - 2019/1/1

Y1 - 2019/1/1

N2 - OBJECTIVE. The purpose of this study is to identify the landmarks and associated radiation dose reduction for limited CT of the kidneys of patients requiring follow-up for known nephrolithiasis. MATERIALS AND METHODS. This retrospective study included all adult patients who underwent CT examination type “CT abdomen + pelvis renal stone” at our institution during 2017. Several exclusion criteria were identified, including scoliosis and congenital renal abnormalities. A total of 299 patients met the inclusion and exclusion criteria. The radiation dose and z-axis length associated with the original CT scan were recorded. The upper and lower limits of both kidneys in relation to the vertebral body endplates were recorded, to determine the z-axis length for a CT scan limited to the kidneys. A commercially available radiation dose analytics software package was used to provide estimates of whole-body– and individual organ–equivalent doses for the original CT scan and the limited range CT scan. RESULTS. The superior endplate of T11 and the inferior endplate of L5 are landmarks that will include both kidneys on almost all scans. A limited z-axis range leads to a mean scan length reduction of 50%. The whole-body mean effective dose is reduced by 41.5%, and the doses to the breast and the gonadal and bladder organs are reduced by 71.7%, 73.8%, and 81.8%, respectively. CONCLUSION. For patients without symptoms who are undergoing CT surveillance to evaluate renal calculi growth, new stone formation, or both, a limited-range scan extending from the superior endplate of T11 to the inferior endplate of L5 results in a significant reduction in radiation dose.

AB - OBJECTIVE. The purpose of this study is to identify the landmarks and associated radiation dose reduction for limited CT of the kidneys of patients requiring follow-up for known nephrolithiasis. MATERIALS AND METHODS. This retrospective study included all adult patients who underwent CT examination type “CT abdomen + pelvis renal stone” at our institution during 2017. Several exclusion criteria were identified, including scoliosis and congenital renal abnormalities. A total of 299 patients met the inclusion and exclusion criteria. The radiation dose and z-axis length associated with the original CT scan were recorded. The upper and lower limits of both kidneys in relation to the vertebral body endplates were recorded, to determine the z-axis length for a CT scan limited to the kidneys. A commercially available radiation dose analytics software package was used to provide estimates of whole-body– and individual organ–equivalent doses for the original CT scan and the limited range CT scan. RESULTS. The superior endplate of T11 and the inferior endplate of L5 are landmarks that will include both kidneys on almost all scans. A limited z-axis range leads to a mean scan length reduction of 50%. The whole-body mean effective dose is reduced by 41.5%, and the doses to the breast and the gonadal and bladder organs are reduced by 71.7%, 73.8%, and 81.8%, respectively. CONCLUSION. For patients without symptoms who are undergoing CT surveillance to evaluate renal calculi growth, new stone formation, or both, a limited-range scan extending from the superior endplate of T11 to the inferior endplate of L5 results in a significant reduction in radiation dose.

KW - CT

KW - Dose

KW - Kidney

KW - Nephrolithiasis

KW - Stone

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