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Choice of area for assessment.

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Choice of Area for Assessment
W. MONTAGUE COBB
Department of A n a t o m y , Howard University College of Medicine,
W a s h i n g t o n , D . C . 20001
ABSTRACT
Multiple areas for assessment of skeletal maturity of an individual (hand, foot, knee, elbow, shoulder, hip) provide the broadest basis for
accurate appraisal. Such studies are becoming progressively less feasible because: (1) the amount of radiation exposure involved may not be permitted; and
(2) the greater time, expense and technical assistance required may not be
justified by the knowledge yielded.
For most statistical series it is desirable today to limit radiographs to one
area. The left hand, including lower forearm, would seem the area of choice.
It is most convenient, permits maximum subject cooperation, is cheapest, most
rapidly done, and may be repeated most often without objection. Uniformity
and clarity of radiograms are also easiest to obtain. Standardization of techniques for use with both fixed and portable machines by widely separated
workers is most readily attained.
For special purposes the choice of area must be determined by the information sought. Special measures will often have to be devised to answer the
questions being investigated.
Gone are the golden days of skeletal
assessment when, as in the period from
about 1930 to 1934, Dr. T. Wingate Todd
used to have for the Brush Foundation
studies large series of children of different backgrounds coming into his Western
Reserve University laboratory to be measured and have x-rays taken of shoulder,
elbow, hand, hip, knee and foot. Some of
these and other children would also have
roentgenograms made for the cranial and
dental investigations of the Bolton Fund
Study.
The data thus accumulated are invaluable, because as with the people of New
Guinea referred to this morning, the opportunity for similar studies is vanishing.
The public today has become radiation
conscious. After the shoe fluoroscopic machines on which one stood, pushed a button and looked at his foot skeleton, became a kind of public scandal, radiologists
everywhere have become sensitive about
using x-rays for purposes which are not
clearly diagnostic or therapeutic. Congressmen particularly, not stimulated by
Ralph Nader, are likely to inquire closely
into the purpose of any technique being
used for the examination of presumably
helpless citizens. It matters not, however,
AM. J. PHYS.ANTHROP.,35: 385-386.
whether we are in the United States or
in any other part of the world, techniques which expose people to radiation
will receive careful scrutiny and demand
for minima1 exposure.
Thus, although multiple areas for assess'ment of the skeletal maturity of an
individual provide the broadest basis for
accurate appraisal, such studies are becoming less feasible not only because. the
amount of radiation exposure involved
may not be permitted, but because the
greater time, expense and technical assistance required may not be justified by
the knowledge yielded.
For most statistical series it is desirable today to limit radiographs to one
area. The left hand, including the lower
forearm, would seem the area of choice.
It is most convenient, permits maximum
subject cooperation, is cheapest, most rapidly done, and may be repeated most often
without objection. Uniformity and clarity
of radiograms are also easiest to obtain
and standardization of techniques for use
with both fixed and portable machines by
widely separated workers is most readily
attained.
For special purposes the choice of area
must be determined by the information
385
386
W. MONTAGUE COBB
TABLE 1
Maresh-Colorado table of exposicresfor radiographs of several areas at diflerent ages
Milli-roentgens per exposure
Focal
film
distance
7'
30"
7'
7'
7'
30"
Chest
Sinuses
Arm
Leg
Head
Hand
Infant
Child
Adolescent
Adult
72
150
10 2
10 2
30
10
14 2
150
10
20 2
80
10
18
200
30
60 2
80
10
20
250
217 m r
284 m r
398
380
100
10
Courtesy of Dr. Marion Maresh, Department of Pediatrics, University of Colorado Medical Center,
Denver.
2 Probably some gonadal irradiation.
1
sought. The case is the same as that for
anthropometric measurements. Hrdlicka
strove for a standardized set of measurements which would be universally utilizable. Boas always pointed out that this
has limitations. Special measurements
would often have to be devised to answer the questions being investigated. So
with radiography for skeletal maturity
assessment.
The amount of radiation exposure involved in x-rays of the hand would permit several films in a year. The National
Committee on Radiation Protection and
Measurement considered in 1960 that
from birth to age 30 a total exposure
of 333 milli-roentgens per year was acceptable.
Dr. Marion Maresh of the Department
of Pediatrics of the University of Colorado
Medical Center, has kindly furnished the
table above on milli-roentgens per expo-
sure which she developed in collaboration
with their Department of Radiology.
This table was calculated to determine
the additive amounts of radiation exposure their subjects would be receiving
through radiographs of chest, sinuses,
arm, leg, hand and head on infants,
children, adolescents and adults.
It will be seen that, if the sinuses are
omitted, even multiple x-rays for skeletal
assessments repeated within a single year
are within safe limits. This scientific fact,
however, is of little avail in the present
climate of public opinion, whether or not
the latter is crystallized in the form of
official regulations.
It was a happy inspiration which made
the designer of the cover of the printed
program for these meetings select the
skeleton of the hand and wrist as seen
by x-ray as the featured emblem. For
future assessment studies the hand is
perforce the area of choice.
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