13. Appendices
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PaX-i3D Smart
options, such as using the single-energy mode linear accelerator rather than the
multimode, orienting the couch and collimator such that the patient lies along the
x-plane and avoiding fields directed along the trunk of the body
3. C. THEODORAKOU, K. HORNER, K. HOWARD, A. WALKER: Pediatric organ and
effective doses in dental cone beam computed tomography
Dental CBCT has been associated with higher radiation risk to the patients compared
to conventional dental X-Ray imaging. Several studies have investigated the radiation
doses involved in dental CBCT for adults but none has looked into pediatric doses.
This study estimates the organ and effective doses to two pediatric tissue-equivalent
phantoms using thermo luminescent dosimeters for three dental CBCT units and
six imaging protocols. The doses to the thyroid, salivary glands and brain ranged
from 0.068mSv to 1.131mSv, 0.708mSv to 2.009mSv and 0.031mSv to 1.584mSv
respectively. The skin and red bone marrow have received much lower doses than the
other three organs. The effective doses ranged from 0.022 mSv to 0.081 mSv. The
effective doses calculated in this study were much higher than these of panoramic
X-Ray imaging but lower than conventional CT
4. CHIYO YAMAUCHI-KAWAURA & KEISUKE FUJII & TAKAHIKO AOYAMA & SHUJI
KOYAMA & MASATO YAMAUCHI: Radiation dose evaluation in head and neck MDCT
examinations with a 6-year-old child anthropomorphic phantom, Pediatr Radiol (2010)
40:1206–1214 DOI 10.1007/s00247-009-1495-z
Background: CT examinations of the head and neck are the most commonly
performed CT studies in children, raising concern about radiation dose and their risks
to children.
Objective: The purpose of this study was to clarify radiation dose levels for children of
6 years of age undergoing head and neck multi-detector CT (MDCT) examinations.
Materials and methods: Radiation doses were measured with small-sized silicon-
photodiode dosimeters that were implanted at various tissue and organ positions
within a standard 6-year-old anthropomorphic phantom. Organ and effective doses of
brain CT were evaluated for 19 protocols in nine hospitals on various (2–320 detector
rows) MDCT scanners.
Results: The maximum value of mean organ dose in brain CT was 34.3 mGy for brain.
Maximum values of mean doses for the radiosensitive lens and thyroid were 32.7 mGy
for lens in brain CT and 17.2 mGy for thyroid in neck CT. seventy-fifth percentile of
effective dose distribution in brain CT was approximately the same as the diagnostic
reference level (DRL) in the 2003 UK survey.
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