How much x-rays can be scattered from a SPECT/CT room to an adjacent gamma camera?

Zong Jian Cao

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The upper limit of the amount of x-rays that are scattered from a SPECT/CT room and are acquired by an adjacent gamma camera is estimated using physical principles and approximations. Methods: We first estimated the amount of xrays scattered from the patient to the ceiling of the SPECT/CT room, then the amount scattered from the ceiling through the gap between the ceiling and the top of lead walls to reach outside of the room, and finally the amount acquired by an adjacent gamma camera into the Tl-201 data. Results: The counts of scattered x-ray photons acquired in the Tl-201 energy window can reach 0.12% of the CT primary counts when the standard 2.13 m high lead walls are used for the SPECT/CT room. Due to the high CT counts, contamination to the Tl-201 data cannot be ignored. It is not effective to reduce the contamination by increase the lead height or change the floor plan because the scattered x-rays reduce moderately with increasing lead height or different floor plans. When the lead height increases from 2.13 m to 2.74 m, for example, the amount of scattered x-rays only decreases by 20%. With the same 2.13 m lead height, there is little difference in the amount of scattered x-rays for three different floor plans. Conclusions: The standard lead walls for a SPECT/CT room cannot prevent scattered x-rays from severe contamination to the Tl-201 data acquired by an adjacent gamma camera. Since dramatic increase of lead height is costly and often prohibitive due to the heavy load, we recommend that Tl-201 studies be stopped when an adjacent CT scanner is in operation.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2009
Subtitle of host publicationPhysics of Medical Imaging
Volume7258
DOIs
StatePublished - Jun 15 2009
EventMedical Imaging 2009: Physics of Medical Imaging - Lake Buena Vista, FL, United States
Duration: Feb 9 2009Feb 12 2009

Other

OtherMedical Imaging 2009: Physics of Medical Imaging
CountryUnited States
CityLake Buena Vista, FL
Period2/9/092/12/09

Fingerprint

Gamma Cameras
rooms
Lead
Cameras
cameras
X-Rays
X rays
ceilings
Ceilings
x rays
contamination
Contamination
Single Photon Emission Computed Tomography Computed Tomography
Photons
scanners
photons
approximation

Keywords

  • Other
  • SCAT

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

Cite this

Cao, Z. J. (2009). How much x-rays can be scattered from a SPECT/CT room to an adjacent gamma camera? In Medical Imaging 2009: Physics of Medical Imaging (Vol. 7258). [72583H] https://doi.org/10.1117/12.811043

How much x-rays can be scattered from a SPECT/CT room to an adjacent gamma camera? / Cao, Zong Jian.

Medical Imaging 2009: Physics of Medical Imaging. Vol. 7258 2009. 72583H.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Cao, ZJ 2009, How much x-rays can be scattered from a SPECT/CT room to an adjacent gamma camera? in Medical Imaging 2009: Physics of Medical Imaging. vol. 7258, 72583H, Medical Imaging 2009: Physics of Medical Imaging, Lake Buena Vista, FL, United States, 2/9/09. https://doi.org/10.1117/12.811043
Cao ZJ. How much x-rays can be scattered from a SPECT/CT room to an adjacent gamma camera? In Medical Imaging 2009: Physics of Medical Imaging. Vol. 7258. 2009. 72583H https://doi.org/10.1117/12.811043
Cao, Zong Jian. / How much x-rays can be scattered from a SPECT/CT room to an adjacent gamma camera?. Medical Imaging 2009: Physics of Medical Imaging. Vol. 7258 2009.
@inproceedings{0ac0305120514f45a3ef58829a6f3f72,
title = "How much x-rays can be scattered from a SPECT/CT room to an adjacent gamma camera?",
abstract = "The upper limit of the amount of x-rays that are scattered from a SPECT/CT room and are acquired by an adjacent gamma camera is estimated using physical principles and approximations. Methods: We first estimated the amount of xrays scattered from the patient to the ceiling of the SPECT/CT room, then the amount scattered from the ceiling through the gap between the ceiling and the top of lead walls to reach outside of the room, and finally the amount acquired by an adjacent gamma camera into the Tl-201 data. Results: The counts of scattered x-ray photons acquired in the Tl-201 energy window can reach 0.12{\%} of the CT primary counts when the standard 2.13 m high lead walls are used for the SPECT/CT room. Due to the high CT counts, contamination to the Tl-201 data cannot be ignored. It is not effective to reduce the contamination by increase the lead height or change the floor plan because the scattered x-rays reduce moderately with increasing lead height or different floor plans. When the lead height increases from 2.13 m to 2.74 m, for example, the amount of scattered x-rays only decreases by 20{\%}. With the same 2.13 m lead height, there is little difference in the amount of scattered x-rays for three different floor plans. Conclusions: The standard lead walls for a SPECT/CT room cannot prevent scattered x-rays from severe contamination to the Tl-201 data acquired by an adjacent gamma camera. Since dramatic increase of lead height is costly and often prohibitive due to the heavy load, we recommend that Tl-201 studies be stopped when an adjacent CT scanner is in operation.",
keywords = "Other, SCAT",
author = "Cao, {Zong Jian}",
year = "2009",
month = "6",
day = "15",
doi = "10.1117/12.811043",
language = "English (US)",
isbn = "9780819475091",
volume = "7258",
booktitle = "Medical Imaging 2009",

}

TY - GEN

T1 - How much x-rays can be scattered from a SPECT/CT room to an adjacent gamma camera?

AU - Cao, Zong Jian

PY - 2009/6/15

Y1 - 2009/6/15

N2 - The upper limit of the amount of x-rays that are scattered from a SPECT/CT room and are acquired by an adjacent gamma camera is estimated using physical principles and approximations. Methods: We first estimated the amount of xrays scattered from the patient to the ceiling of the SPECT/CT room, then the amount scattered from the ceiling through the gap between the ceiling and the top of lead walls to reach outside of the room, and finally the amount acquired by an adjacent gamma camera into the Tl-201 data. Results: The counts of scattered x-ray photons acquired in the Tl-201 energy window can reach 0.12% of the CT primary counts when the standard 2.13 m high lead walls are used for the SPECT/CT room. Due to the high CT counts, contamination to the Tl-201 data cannot be ignored. It is not effective to reduce the contamination by increase the lead height or change the floor plan because the scattered x-rays reduce moderately with increasing lead height or different floor plans. When the lead height increases from 2.13 m to 2.74 m, for example, the amount of scattered x-rays only decreases by 20%. With the same 2.13 m lead height, there is little difference in the amount of scattered x-rays for three different floor plans. Conclusions: The standard lead walls for a SPECT/CT room cannot prevent scattered x-rays from severe contamination to the Tl-201 data acquired by an adjacent gamma camera. Since dramatic increase of lead height is costly and often prohibitive due to the heavy load, we recommend that Tl-201 studies be stopped when an adjacent CT scanner is in operation.

AB - The upper limit of the amount of x-rays that are scattered from a SPECT/CT room and are acquired by an adjacent gamma camera is estimated using physical principles and approximations. Methods: We first estimated the amount of xrays scattered from the patient to the ceiling of the SPECT/CT room, then the amount scattered from the ceiling through the gap between the ceiling and the top of lead walls to reach outside of the room, and finally the amount acquired by an adjacent gamma camera into the Tl-201 data. Results: The counts of scattered x-ray photons acquired in the Tl-201 energy window can reach 0.12% of the CT primary counts when the standard 2.13 m high lead walls are used for the SPECT/CT room. Due to the high CT counts, contamination to the Tl-201 data cannot be ignored. It is not effective to reduce the contamination by increase the lead height or change the floor plan because the scattered x-rays reduce moderately with increasing lead height or different floor plans. When the lead height increases from 2.13 m to 2.74 m, for example, the amount of scattered x-rays only decreases by 20%. With the same 2.13 m lead height, there is little difference in the amount of scattered x-rays for three different floor plans. Conclusions: The standard lead walls for a SPECT/CT room cannot prevent scattered x-rays from severe contamination to the Tl-201 data acquired by an adjacent gamma camera. Since dramatic increase of lead height is costly and often prohibitive due to the heavy load, we recommend that Tl-201 studies be stopped when an adjacent CT scanner is in operation.

KW - Other

KW - SCAT

UR - http://www.scopus.com/inward/record.url?scp=66749148417&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=66749148417&partnerID=8YFLogxK

U2 - 10.1117/12.811043

DO - 10.1117/12.811043

M3 - Conference contribution

AN - SCOPUS:66749148417

SN - 9780819475091

VL - 7258

BT - Medical Imaging 2009

ER -