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Value
of Computed
BAHMAN
EMAMI,’
Tomography
AGUSTIN
MELO,’ AND
in Radiotherapy
BARBARA ANTHONY
The effectiveness of CT scanning In radiotherapeutic treatment planning was evaluated in 32 patients with bronchogenic carcinoma. CT of the chest in pretreatment evaluation of these patients supplemented conventional clinical and radiographic studies, resulting in (1) more clear delineation of tumor extent in 24 patients (75%); (2) change In assessment of the size of lesions in 14 patients (43%); (3) change of disease stage in 13 (40%); (4) demonstration of inadequacy of treatment plan in nine (28%); and (5) changes in the volume of normal tissue irradiated in 13 (40%). CT scan data was judged essential for treatment planning in 17 patIents studied (53%). Unsuspected areas of tumor Involvement were seen in 21 patients (65%). Use of the CT scan as a patient contour for radiotherapy treatment planning of lung cancer and alternative techniques are discussed.
L. CARTER,2 J. PIRO1
[4, 8, 9].
ity data average
JOHN
It also
from
of Lung
has
E. MUNZENRIDER,1’3
been
CT scans
difference
shown
that
use
in the thoracic between
dose 12.4%-3.4% ing inhomogeneity
Cancer
calculated
[10], a difference corrections to
calculations. The technique tumor response to treatment
Between August 1975 bronchogenic carcinoma of Therapeutic Radiology
Radiotherapy depends heavily on radiographic and other imaging techniques for diagnosis, determination of tumor extent, and localizing tumors so as to minimize irradiation of uninvolved normal tissue while adequately
reduced
and
the
measured
significant in applyphoton beam dose
is also useful in assessing by serial scanning [4]. This
report examines our experience with planning for 32 patients with bronchial
Subjects
of inhomogene-
region
and
CT in treatment cancer.
Methods
and December 1977, 32 patients with who were treated in the Department at Tufts-New England Medical Center
had chest CT scans prior to radiotherapy
which
were eventually
used in treatment planning. There were 22 males and 10 females aged 34-79 years (mean, 60.5 years). There were 18 squamous cell carcinomas, seven adenocarcinomas, and seven undiffer-
invac ng posterior chest wall (not shown). extended cephalad through thoracic inlet (black arrow) ing traches to right. Involvement of chest wall anteriorly and posteriory was best seen by CT. Although mediastinal and pleural disease were apparent (arrowhead)
treating
the
tumor.
Previous
reports
on
whole
body
computed tomography (CT) demonstrate its value as a useful diagnostic method [1-3]. A few reports describe its application to evaluation of the chest [2-6]. It has been suggested that total body CT provides an exact contour of a transverse section at the level of the tumor, also displaying tumor location and size in a given section
on
entiated
CT sections can processed directly
be enlarged for treatment
films,
total
extent
carcinomas.
of tumor
Procedures
was
better
delineated
by CT.
used
in initial
evaluation
to actual planning
Received March 16, 1978; accepted after revision April 12, 1978. ‘Department of Therapeutic Radiology, Tufts-New England Medical Center Hospital, 171 Harrison Avenue, Boston, reprint requests to B. Emami. 2Department of Diagnostic Radiology, Tufts-New England Medical Center Hospital, Boston, Massachusetts 02111. 3Present address: Department of Radiation Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114. Am J Roentgenol
Ic 1978 American
131 :63-67, July 1978 Roentgen Ray Society
in
addition to conventional radiographic films and CT scan were tomography (four patients), bronchoscopy (1 5), thoracotomy (four), mediastinoscopy (five), percutaneous lung biopsy (five), sputum cytology (one), node biopsy (one), and cytologic examination of pleural effusion (one patient). CT scans were obtained on an Ohio Nuclear Delta scanner
[4,7].
Appropriate body size and
plain
63
Massachusetts
0361 -803X/78/0700
021 1 1 .
-
0063
Address
$00.00
EMAMI
Downloaded from www.ajronline.org by NYU Langone Med Ctr-Sch of Med on 06/14/15 from IP address 128.122.253.212. Copyright ARRS. For personal use only; all rights reserved
64
Fig.
2.-Pleural
indicate
invasion
proposed
therapy
by cancer
(arrows)
portal which required
ET
AL.
is much easier to appreciate by CT than by plain film studies. modification after CT to include entire tumor.
plotter by visual transfer drawn contour obtained mold or by photographic [4].
Barium
was placed
on skin surface
to
of data from CT scan to manually with flexible wire or plaster of paris full-scale enlargement of the CT image
Results Tumors sole with
tasis
on
not
Fig.
3.-Patient
information
with
for
most
row) and metastatic were included in mum
exposure
bronchogenic
carcinoma.
CT provided
necessary
effective treatment. Primary carcinoma (white arnodes within mediastinum, in latter part of treatment,
two
opposing
to normal
oblique
coned
down
portals
with mini-
lung.
with a 256 x 256 matrix, with a scan time of 2.5 mm and slice thickness of 13 mm. Original hard copy was a black-and-white Polaroid print, but more recent scans were displayed on conventional x-ray film with usual dimensions ranging from 3 x 5 to 5 x 7 cm, although larger images with greater detail can be obtained. To assess the contribution of the CT information, the patient charts, pretreatment radiographs, and CT scans were reviewed retrospectively. One of us (B. L. Carter) examined the radiographs
independently
and
independent
of
other
information.
Her assessment of the extent of tumor was then incorporated by B. Emami in treatment planning exercises. The staging, treatment plan, and technique were initially developed excluding CT information
and
a second
time
including
CT
data.
The
results
and without scan were compared. In almost all instances the actual treatment program corresponded to the second plan, incorporating the CT information. Pathologic proof of the validity of the CT interpretations was only available in a few instances. This limitation is recognized. but clinical considerations denied the surgical explorations that would have been required to obtain it. The interpretations were accepted as valid and modified the management of the patients as hereafter described. Radiotherapy was planned using all available data including physical examination , radiographic studies , surgical notes , and CT scans. The CT scan was displayed for inputting to the treatment planning Artronix P.C. 12 computer with the rho-theta with
were
seen
exception had the suggestion
in 31 of the
radiographic
studies
on
The
subsequent
CT
scan.
patient’s
confirmed this diagnosis. tumor extent in 24 patients radiography (fig. 1). By virtue Comparative larger on in seven
measuring
actual
CT
size
films
tumor
size
scan. The
treatment
patients
delineated plain chest
gives
a better
the
tumors.
of
of tumor (due
could
be
In 10
necessary
were
to include
was
not
possible
effusion,
measured
volume
(37.5%).
size
to atelectasia, in
most
altered
patients
by
all tumor
patients
(28%).
treatment
CT
scan
a larger
(fig.
essential
treatment and not
scan
was
patients. previously pected
in 17 patients
areas other
In
11 patients, unsuspected
nodes areas
In two
of involvement data were seen
were of
tumor
patients,
direct areas
found areas
of
in two
for
in a signifi-
CT
was
14
patients
would CT was
helpful
in (44%)
by tumor not sugon CT scan in 21
extension was seen
in nine
involvement
12
sufficient the tumor in nine
essential
resulted
(53%).
in
CT
volume
2), and
judged
planning in an additional useful in one patient (3%).
Thirty-two gested from
1).
CT
if its availability
on
change in volume or if a portion of the tumor been missed without it. Using these criteria,
judged
other
The
planning
while
patients
(31%),
on
etc.),
patients (6.5%) a smaller volume was judged (fig. 3). CT scans showed that coverage of from all other studies was clearly inadequate
cant have
was course
measurements revealed the tumor to be CT scan in 12, smaller in two, and unchanged relative to conventional films. In 11 patients,
chest
was
view,
the
measurements
plain
The
which
CT more clearly (75%) relative to
of three-dimensional
of
actual
(95%).
conventional
seen
means
32 CT scans
early superior vena caval obstruction of a small paratracheal nodal metas-
of tumor into (fig. 4). Unsus-
patients were
involvement
(fig. seen
5),
in six suggested
while (table by
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CT
IN
MANAGEMENT
OF
LUNG
arch,
conventional
radiographs
subsequent
CT
tional
whole
scan
revealed
on
scan.
lung
the
four
while
was
normal
CT
data
patients,
changed
increasing
2). Nodal The
TNM
system
disease
metastasis
puts
are
present
(Ml)
percentage of the radical radiotherapy incurable
with
Ill,
the
to a lower
As noted ophy
of
patients
tive
another
tumor
(T)
stage
lowering
radical
with
regardless
(table
of CT data
advanced
locore-
(MO). may all
be the
methods.
distinct
A significant cured former
with are
In table
4 the
Fig. 5.-Bronchogenic carcinoma invades right hilum (arrow) around right main pulmonary artery just anterior to right bronchus intermedius. Primary carcinoma, small nodule in right upper lobe, could be seen with some difficulty on plain films; mestastasis to right hilum and mediastinum was much more apparent on CT scan. Barium was placed on skin surface to indicate
5, the CT findings patients,
altered changing
and
in one
the
proposed
treatment
portal.
it in from
TABLE
philosUnsuspected
four
pallia-
tomography.
Miller
et al.
Shown
Area
by CT Metastasis
Direct Ex’ tension
Nodes: Mediastinal Hilar Lower Neck Axilla Bone Pleural invasion Pleural effusion Additional nodules: Parenchyma
The results of this study support the conclusions of others [4, 6] concerning the usefulness of CT scanning in pretherapy evaluation of lung cancer. Stanley et al. [2] found that CT was “beneficial” in 36% (four of 11) of patients with chest “tumors,” providing diagnostic information not apparent on chest radiography. Muhm et al. [6] reported that CT detected more pulmonary nodules in 10 of 29 patients studied with both CT scanning and lung
1
Involvement
Involved
Discussion
whole
could
of CT
to radical.
conventional
Latter
(arrows).
in 14 (44%)
it in one
of whether
or absent
to palliative
body
of the
by inclusion
therapeutic
in five
vertebral
patient,
stage.
in table
treatment from
thoracic
CT
TNM stage before CT is compared to that after CT was obtained. As a result of CT data, 14 of the 32 patients (44%) had alteration in stage, 13 to a higher stage and one
second
not visible
to the TNM system with and without
latter category [11-13], while
known
destroying
not be seen on plain chest films even in retrospect.
on CT scan.
patients
in stage
on
conven-
involvement
(N) stage was increased patients (table 3).
in nine gional
the
it in 13 and
had of these,
in
Patients were staged according American Joint Committees
data.
normal
of tumor
suggested
which
be
patients
on extent
tomography
lung
to
in one
tomograms
lung
opposite
Only
found
tomography;
information
conventional
whole
were
65
CANCER
7 2 1 2 1
5 6
.
.
4 1
1
Chestwall
1
.
.
Pericardium
1
.
.
[14]
and Castellino et al. [15] showed that conventional whole lung tomography provides additional information in 10%-20% of patients compared with plain chest radiog-
not
elicited
raphy.
including
Mink et al. [16], in studying thymomas, reported that CT clearly identified a tumor which was only suggested by conventional means. In addition, in three of five cases, CT resulted in significant diagnostic information
Sternick ated from
by other
lymph
node
with
lymphoma,
not
by
seen
Kreel CT
[17]
in eight
in other
demonstrated of
14
radiographic
patients
studies
lymphangiography.
transverse much
studies.
enlargement
et al. [18] compared CT scan data with axial
as
10%
tomography for
calculated
treatment those from and tumor
found dose
plans generconventional deviations as and
20%
for
EMAMI
66 TABLE
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Alteration
ET AL.
2
in T Category TafterCT
T before CT
Total Ti
Ti 12 T3
2
Total
T2
T3
2
4
5 1
11 11
16 12
6
24
32
...
2
TABLE Alteration
3
in N Category N after Ct
N before
Total
CT NO
NO Ni N2 Total
Ni
N2
5
2 8
5 2 10
12 10 10
5
10
17
32
Fig. 6.-Patient with malignant pleural effusion (white arrow) but unknown primary. Unsuspected bronchogenic carcinoma (black arrow) was detected by CT scan, not seen on plain films in presence of fluid.
argued that demonstrated
some of the findings by that technique.
tomography TABLE Alteration
x-ray, Staging
Stage Stage
before
after
four
CT
CT
Total I
II
Ill. Mi
III.MO
I
8
II III,MO III,M1 Total .
Axillary
nodes
positive
on CT scan
Treatment
Policy
before
3 13
2
24
(no histologic
TABLE Alteration
1 1
.
..
.
..
2* 4
8 4 16 4
6
32
5 Policy
Treatment
Policy after CT Total
Total
17
darker
in whom
gray
and/or
Palliative
Palliative
patients
both
background,
involvement hilar areas,
CT
16
than
plain
chest
studies
were
performed.
as
in plain
chest
whole lung tomography. 10 mm) which most
radiography
Smaller likely would
nodbe
missed by other procedures can be detected by CT.* Transverse orientation of CT scans eliminates the problem of superimposition of bony or cardiovascular images over the tumor. CT offers more precise demonstration of
in Treatment
Radical
accurate
study
There seem to be inherent advantages of CT. Lesions are more readily visualized by virtue of display format: nodules are depicted as white spots against a dark gray background, rather than as a lighter gray spot on a or conventional ules (less than
confirmation).
Radical
in this
more
CT was 75% more accurate than plain chest films. In addition, as noted above, CT was clearly superior to conventional tomography in two of
4
in Clinical
is 10%-20%
while
on CT might have been However, conventional
4
20
ii
12
15
32
of pleura, and metastasis
thoracic
and lungs
cage.
Occasionally the assessment
pleural effusion of exact tumor
radiography
and
However,
chest wall, mediastinum, to other portions of the
fluid
even can
on
usually
may cause difficulty in extent on plain chest
conventional
tomography.
be
on
delineated
the
scan
from tumor (fig. 6). If doubt persists, it may be resolved by scanning in the prone position if the initial scan was supine, or vice versa. spinal tissue
cord dose. inhomogeneity
They observed corrections
that patient-specific can be obtained from
CT but not from conventional tomog rams. In our series, compared to conventional radiography, CT revealed significantly better delineation of tumor extent in 24 of 32 patients, more accurate assessment of the size of the lesion in 14, more adequate coverage of tumor
extent
by radiotherapy
tion in patients.
irradiated volume of Conventional whole
formed
in
only
four
of
our
portals
in nine, and
normal tissue lung tomography 32
patients.
Thus
in
altera-
13 of 32 was perit can
be
In conclusion, ment
were
32 unsuspected found
clinical
staging
changes
of
availability accuracy
Editor’s
to note.
the
precision
radiotherapy
32
Schaner
the
of tumor
patients
in on
five
cancer
target
volume
which
has
desired
These
patients.
lung
With
seems
the the to
achieved
and treatment
et al. in this issue.
and
led to
patients,
been
dose
involve-
studied,
in 13 patients.
techniques
deliver
-See
areas
the
policy data
defining the
of
changed
treatment
of
computers *
was
of CT scan
approaching
modern
in 21
to
planning a specified
be by
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CT
IN MANAGEMENT
target volume. Thus local treatment failure as a result of inadequate definition of tumor and nodal extent should decrease. More confident selection of patients for radical radiotherapy should be possible, while for others with uncontrollable bone or chest wall invasion, palliative techniques should be more appropriately offered.
the body: early trends in application and accuracy of the method. Am J Roentgenol 127 : 53-67, 1976 3. Sheedy PF II, Stephens DH, Hattery AR, Muhm J, Hartman GW: Computed tomography of the body: initial clinical trial with EMI prototype. Am J Roentgenol 127 :23-51 1976 4. Munzenrider JE, Pilepich M, Aene-Ferrero JB, Tchakarova I, Carter BL: Use of body scanner in radiotherapy treatment planning. Cancer 40: 170-179, 1977 ,
BM,
Korobkin
6.
7.
8.
omental
M, Hall AD: Computed
tomography
and other mediastinal fatty masses. J Comput Assist Tomogr 1 : 181-1 83, 1977 Muhm JE, Brown LA, Crowe JK: Use of computed tomography in the detection of pulmonary nodules. Mayo Clin Proc 52:345-348, 1977 Jost AG, Sagel SS, Stanley AG, Levitt AG: Computed tomography of the thorax. Radiology 126: 125-136, 1978 Geise RA, McCullough EC: The use of CT scanners in megavoltage photon-beam therapy planning Radiology 124 : 133-141 1977 Cherriak ES, Aodriquez-Antunez A, Jelden GL, Dhaliwal
herniation
.
,
9.
iO.
CANCER
67
Lavik PS: The use of computed tomography for radiatherapy treatment planning. Radiology i17:613-614,
1975 Sontag MA, Implications
corrections
Battista JJ, of computed
in photon
Bronskill MJ, Cunningham JA: tomography for inhomogeneity beam dose calculations. Radiology
124:143-149, 1977 Emami B, Lee DJ, Munzenrider
evaluation
1 . Sagel S, Stanley AJ, Evans AG: Early clinical experience with motionless whole body computed tomography. Radiology 119:321-330, 1976 2. Stanley AJ, Sagel SS, Levitt AG: Computed tomography of
of intrathoracic
LUNG
AS, tion
11.
REFERENCES
5. Rohlfing
OF
of prognostic
JE: Inoperable
factors
and
results
lung
cancer:
of radical
radiotherapy. Submitted for publication 12. Aristizabal SA, Caldwell WL: Radical irradiation with the split-course technique in carcinoma of the lung. Cancer 37 :2630-2635, 1976 13. Salazar OM, Aubin P, Brown JC, Feldsteiri ML, Keller BE: Predictors of radiation response in lung cancer. Cancer
37:2636-2650,
1976
14.
MillerWE, CrowJA, MuhmJA: Theevaluation of pulmonary parenchymal abnormalities by tomography. Radio! Clin NorthAm 14:85-93, 1976 15. Castellino RA, Filly A, Blank N: Routine full-lung tomography in the initial staging and treatment planning of patients with Hodgkin’s disease and non-Hodgkin’s lymphoma. Cancer 38 :1 130-i 136, 1976 16. Mink JH, Bein ME, Sukov A, Herrman C Jr, Winter J,
Sample nor
WF, Maider
mediastinum
D: Computed
tomography
of the ante-
in patients with myasthenia gravis and suspected thymomas. Am J Roentgeno! 130 : 239-246, 1978 17. Kreel L: The EMI whole body scanner in the demonstration of lymph node enlargement. Clin Radio! 27 : 421 -429, 1976 18. Sternick ES, Lane FW, Curran B: Comparison of computed tomography and conventional transverse axial tomography in radiotherapy treatment planning. Radiology 124 : 835836, 1977
Value
of Computed
BAHMAN
EMAMI,’
Tomography
AGUSTIN
MELO,’ AND
in Radiotherapy
BARBARA ANTHONY
The effectiveness of CT scanning In radiotherapeutic treatment planning was evaluated in 32 patients with bronchogenic carcinoma. CT of the chest in pretreatment evaluation of these patients supplemented conventional clinical and radiographic studies, resulting in (1) more clear delineation of tumor extent in 24 patients (75%); (2) change In assessment of the size of lesions in 14 patients (43%); (3) change of disease stage in 13 (40%); (4) demonstration of inadequacy of treatment plan in nine (28%); and (5) changes in the volume of normal tissue irradiated in 13 (40%). CT scan data was judged essential for treatment planning in 17 patIents studied (53%). Unsuspected areas of tumor Involvement were seen in 21 patients (65%). Use of the CT scan as a patient contour for radiotherapy treatment planning of lung cancer and alternative techniques are discussed.
L. CARTER,2 J. PIRO1
[4, 8, 9].
ity data average
JOHN
It also
from
of Lung
has
E. MUNZENRIDER,1’3
been
CT scans
difference
shown
that
use
in the thoracic between
dose 12.4%-3.4% ing inhomogeneity
Cancer
calculated
[10], a difference corrections to
calculations. The technique tumor response to treatment
Between August 1975 bronchogenic carcinoma of Therapeutic Radiology
Radiotherapy depends heavily on radiographic and other imaging techniques for diagnosis, determination of tumor extent, and localizing tumors so as to minimize irradiation of uninvolved normal tissue while adequately
reduced
and
the
measured
significant in applyphoton beam dose
is also useful in assessing by serial scanning [4]. This
report examines our experience with planning for 32 patients with bronchial
Subjects
of inhomogene-
region
and
CT in treatment cancer.
Methods
and December 1977, 32 patients with who were treated in the Department at Tufts-New England Medical Center
had chest CT scans prior to radiotherapy
which
were eventually
used in treatment planning. There were 22 males and 10 females aged 34-79 years (mean, 60.5 years). There were 18 squamous cell carcinomas, seven adenocarcinomas, and seven undiffer-
invac ng posterior chest wall (not shown). extended cephalad through thoracic inlet (black arrow) ing traches to right. Involvement of chest wall anteriorly and posteriory was best seen by CT. Although mediastinal and pleural disease were apparent (arrowhead)
treating
the
tumor.
Previous
reports
on
whole
body
computed tomography (CT) demonstrate its value as a useful diagnostic method [1-3]. A few reports describe its application to evaluation of the chest [2-6]. It has been suggested that total body CT provides an exact contour of a transverse section at the level of the tumor, also displaying tumor location and size in a given section
on
entiated
CT sections can processed directly
be enlarged for treatment
films,
total
extent
carcinomas.
of tumor
Procedures
was
better
delineated
by CT.
used
in initial
evaluation
to actual planning
Received March 16, 1978; accepted after revision April 12, 1978. ‘Department of Therapeutic Radiology, Tufts-New England Medical Center Hospital, 171 Harrison Avenue, Boston, reprint requests to B. Emami. 2Department of Diagnostic Radiology, Tufts-New England Medical Center Hospital, Boston, Massachusetts 02111. 3Present address: Department of Radiation Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114. Am J Roentgenol
Ic 1978 American
131 :63-67, July 1978 Roentgen Ray Society
in
addition to conventional radiographic films and CT scan were tomography (four patients), bronchoscopy (1 5), thoracotomy (four), mediastinoscopy (five), percutaneous lung biopsy (five), sputum cytology (one), node biopsy (one), and cytologic examination of pleural effusion (one patient). CT scans were obtained on an Ohio Nuclear Delta scanner
[4,7].
Appropriate body size and
plain
63
Massachusetts
0361 -803X/78/0700
021 1 1 .
-
0063
Address
$00.00
EMAMI
Downloaded from www.ajronline.org by NYU Langone Med Ctr-Sch of Med on 06/14/15 from IP address 128.122.253.212. Copyright ARRS. For personal use only; all rights reserved
64
Fig.
2.-Pleural
indicate
invasion
proposed
therapy
by cancer
(arrows)
portal which required
ET
AL.
is much easier to appreciate by CT than by plain film studies. modification after CT to include entire tumor.
plotter by visual transfer drawn contour obtained mold or by photographic [4].
Barium
was placed
on skin surface
to
of data from CT scan to manually with flexible wire or plaster of paris full-scale enlargement of the CT image
Results Tumors sole with
tasis
on
not
Fig.
3.-Patient
information
with
for
most
row) and metastatic were included in mum
exposure
bronchogenic
carcinoma.
CT provided
necessary
effective treatment. Primary carcinoma (white arnodes within mediastinum, in latter part of treatment,
two
opposing
to normal
oblique
coned
down
portals
with mini-
lung.
with a 256 x 256 matrix, with a scan time of 2.5 mm and slice thickness of 13 mm. Original hard copy was a black-and-white Polaroid print, but more recent scans were displayed on conventional x-ray film with usual dimensions ranging from 3 x 5 to 5 x 7 cm, although larger images with greater detail can be obtained. To assess the contribution of the CT information, the patient charts, pretreatment radiographs, and CT scans were reviewed retrospectively. One of us (B. L. Carter) examined the radiographs
independently
and
independent
of
other
information.
Her assessment of the extent of tumor was then incorporated by B. Emami in treatment planning exercises. The staging, treatment plan, and technique were initially developed excluding CT information
and
a second
time
including
CT
data.
The
results
and without scan were compared. In almost all instances the actual treatment program corresponded to the second plan, incorporating the CT information. Pathologic proof of the validity of the CT interpretations was only available in a few instances. This limitation is recognized. but clinical considerations denied the surgical explorations that would have been required to obtain it. The interpretations were accepted as valid and modified the management of the patients as hereafter described. Radiotherapy was planned using all available data including physical examination , radiographic studies , surgical notes , and CT scans. The CT scan was displayed for inputting to the treatment planning Artronix P.C. 12 computer with the rho-theta with
were
seen
exception had the suggestion
in 31 of the
radiographic
studies
on
The
subsequent
CT
scan.
patient’s
confirmed this diagnosis. tumor extent in 24 patients radiography (fig. 1). By virtue Comparative larger on in seven
measuring
actual
CT
size
films
tumor
size
scan. The
treatment
patients
delineated plain chest
gives
a better
the
tumors.
of
of tumor (due
could
be
In 10
necessary
were
to include
was
not
possible
effusion,
measured
volume
(37.5%).
size
to atelectasia, in
most
altered
patients
by
all tumor
patients
(28%).
treatment
CT
scan
a larger
(fig.
essential
treatment and not
scan
was
patients. previously pected
in 17 patients
areas other
In
11 patients, unsuspected
nodes areas
In two
of involvement data were seen
were of
tumor
patients,
direct areas
found areas
of
in two
for
in a signifi-
CT
was
14
patients
would CT was
helpful
in (44%)
by tumor not sugon CT scan in 21
extension was seen
in nine
involvement
12
sufficient the tumor in nine
essential
resulted
(53%).
in
CT
volume
2), and
judged
planning in an additional useful in one patient (3%).
Thirty-two gested from
1).
CT
if its availability
on
change in volume or if a portion of the tumor been missed without it. Using these criteria,
judged
other
The
planning
while
patients
(31%),
on
etc.),
patients (6.5%) a smaller volume was judged (fig. 3). CT scans showed that coverage of from all other studies was clearly inadequate
cant have
was course
measurements revealed the tumor to be CT scan in 12, smaller in two, and unchanged relative to conventional films. In 11 patients,
chest
was
view,
the
measurements
plain
The
which
CT more clearly (75%) relative to
of three-dimensional
of
actual
(95%).
conventional
seen
means
32 CT scans
early superior vena caval obstruction of a small paratracheal nodal metas-
of tumor into (fig. 4). Unsus-
patients were
involvement
(fig. seen
5),
in six suggested
while (table by
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CT
IN
MANAGEMENT
OF
LUNG
arch,
conventional
radiographs
subsequent
CT
tional
whole
scan
revealed
on
scan.
lung
the
four
while
was
normal
CT
data
patients,
changed
increasing
2). Nodal The
TNM
system
disease
metastasis
puts
are
present
(Ml)
percentage of the radical radiotherapy incurable
with
Ill,
the
to a lower
As noted ophy
of
patients
tive
another
tumor
(T)
stage
lowering
radical
with
regardless
(table
of CT data
advanced
locore-
(MO). may all
be the
methods.
distinct
A significant cured former
with are
In table
4 the
Fig. 5.-Bronchogenic carcinoma invades right hilum (arrow) around right main pulmonary artery just anterior to right bronchus intermedius. Primary carcinoma, small nodule in right upper lobe, could be seen with some difficulty on plain films; mestastasis to right hilum and mediastinum was much more apparent on CT scan. Barium was placed on skin surface to indicate
5, the CT findings patients,
altered changing
and
in one
the
proposed
treatment
portal.
it in from
TABLE
philosUnsuspected
four
pallia-
tomography.
Miller
et al.
Shown
Area
by CT Metastasis
Direct Ex’ tension
Nodes: Mediastinal Hilar Lower Neck Axilla Bone Pleural invasion Pleural effusion Additional nodules: Parenchyma
The results of this study support the conclusions of others [4, 6] concerning the usefulness of CT scanning in pretherapy evaluation of lung cancer. Stanley et al. [2] found that CT was “beneficial” in 36% (four of 11) of patients with chest “tumors,” providing diagnostic information not apparent on chest radiography. Muhm et al. [6] reported that CT detected more pulmonary nodules in 10 of 29 patients studied with both CT scanning and lung
1
Involvement
Involved
Discussion
whole
could
of CT
to radical.
conventional
Latter
(arrows).
in 14 (44%)
it in one
of whether
or absent
to palliative
body
of the
by inclusion
therapeutic
in five
vertebral
patient,
stage.
in table
treatment from
thoracic
CT
TNM stage before CT is compared to that after CT was obtained. As a result of CT data, 14 of the 32 patients (44%) had alteration in stage, 13 to a higher stage and one
second
not visible
to the TNM system with and without
latter category [11-13], while
known
destroying
not be seen on plain chest films even in retrospect.
on CT scan.
patients
in stage
on
conven-
involvement
(N) stage was increased patients (table 3).
in nine gional
the
it in 13 and
had of these,
in
Patients were staged according American Joint Committees
data.
normal
of tumor
suggested
which
be
patients
on extent
tomography
lung
to
in one
tomograms
lung
opposite
Only
found
tomography;
information
conventional
whole
were
65
CANCER
7 2 1 2 1
5 6
.
.
4 1
1
Chestwall
1
.
.
Pericardium
1
.
.
[14]
and Castellino et al. [15] showed that conventional whole lung tomography provides additional information in 10%-20% of patients compared with plain chest radiog-
not
elicited
raphy.
including
Mink et al. [16], in studying thymomas, reported that CT clearly identified a tumor which was only suggested by conventional means. In addition, in three of five cases, CT resulted in significant diagnostic information
Sternick ated from
by other
lymph
node
with
lymphoma,
not
by
seen
Kreel CT
[17]
in eight
in other
demonstrated of
14
radiographic
patients
studies
lymphangiography.
transverse much
studies.
enlargement
et al. [18] compared CT scan data with axial
as
10%
tomography for
calculated
treatment those from and tumor
found dose
plans generconventional deviations as and
20%
for
EMAMI
66 TABLE
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Alteration
ET AL.
2
in T Category TafterCT
T before CT
Total Ti
Ti 12 T3
2
Total
T2
T3
2
4
5 1
11 11
16 12
6
24
32
...
2
TABLE Alteration
3
in N Category N after Ct
N before
Total
CT NO
NO Ni N2 Total
Ni
N2
5
2 8
5 2 10
12 10 10
5
10
17
32
Fig. 6.-Patient with malignant pleural effusion (white arrow) but unknown primary. Unsuspected bronchogenic carcinoma (black arrow) was detected by CT scan, not seen on plain films in presence of fluid.
argued that demonstrated
some of the findings by that technique.
tomography TABLE Alteration
x-ray, Staging
Stage Stage
before
after
four
CT
CT
Total I
II
Ill. Mi
III.MO
I
8
II III,MO III,M1 Total .
Axillary
nodes
positive
on CT scan
Treatment
Policy
before
3 13
2
24
(no histologic
TABLE Alteration
1 1
.
..
.
..
2* 4
8 4 16 4
6
32
5 Policy
Treatment
Policy after CT Total
Total
17
darker
in whom
gray
and/or
Palliative
Palliative
patients
both
background,
involvement hilar areas,
CT
16
than
plain
chest
studies
were
performed.
as
in plain
chest
whole lung tomography. 10 mm) which most
radiography
Smaller likely would
nodbe
missed by other procedures can be detected by CT.* Transverse orientation of CT scans eliminates the problem of superimposition of bony or cardiovascular images over the tumor. CT offers more precise demonstration of
in Treatment
Radical
accurate
study
There seem to be inherent advantages of CT. Lesions are more readily visualized by virtue of display format: nodules are depicted as white spots against a dark gray background, rather than as a lighter gray spot on a or conventional ules (less than
confirmation).
Radical
in this
more
CT was 75% more accurate than plain chest films. In addition, as noted above, CT was clearly superior to conventional tomography in two of
4
in Clinical
is 10%-20%
while
on CT might have been However, conventional
4
20
ii
12
15
32
of pleura, and metastasis
thoracic
and lungs
cage.
Occasionally the assessment
pleural effusion of exact tumor
radiography
and
However,
chest wall, mediastinum, to other portions of the
fluid
even can
on
usually
may cause difficulty in extent on plain chest
conventional
tomography.
be
on
delineated
the
scan
from tumor (fig. 6). If doubt persists, it may be resolved by scanning in the prone position if the initial scan was supine, or vice versa. spinal tissue
cord dose. inhomogeneity
They observed corrections
that patient-specific can be obtained from
CT but not from conventional tomog rams. In our series, compared to conventional radiography, CT revealed significantly better delineation of tumor extent in 24 of 32 patients, more accurate assessment of the size of the lesion in 14, more adequate coverage of tumor
extent
by radiotherapy
tion in patients.
irradiated volume of Conventional whole
formed
in
only
four
of
our
portals
in nine, and
normal tissue lung tomography 32
patients.
Thus
in
altera-
13 of 32 was perit can
be
In conclusion, ment
were
32 unsuspected found
clinical
staging
changes
of
availability accuracy
Editor’s
to note.
the
precision
radiotherapy
32
Schaner
the
of tumor
patients
in on
five
cancer
target
volume
which
has
desired
These
patients.
lung
With
seems
the the to
achieved
and treatment
et al. in this issue.
and
led to
patients,
been
dose
involve-
studied,
in 13 patients.
techniques
deliver
-See
areas
the
policy data
defining the
of
changed
treatment
of
computers *
was
of CT scan
approaching
modern
in 21
to
planning a specified
be by
Downloaded from www.ajronline.org by NYU Langone Med Ctr-Sch of Med on 06/14/15 from IP address 128.122.253.212. Copyright ARRS. For personal use only; all rights reserved
CT
IN MANAGEMENT
target volume. Thus local treatment failure as a result of inadequate definition of tumor and nodal extent should decrease. More confident selection of patients for radical radiotherapy should be possible, while for others with uncontrollable bone or chest wall invasion, palliative techniques should be more appropriately offered.
the body: early trends in application and accuracy of the method. Am J Roentgenol 127 : 53-67, 1976 3. Sheedy PF II, Stephens DH, Hattery AR, Muhm J, Hartman GW: Computed tomography of the body: initial clinical trial with EMI prototype. Am J Roentgenol 127 :23-51 1976 4. Munzenrider JE, Pilepich M, Aene-Ferrero JB, Tchakarova I, Carter BL: Use of body scanner in radiotherapy treatment planning. Cancer 40: 170-179, 1977 ,
BM,
Korobkin
6.
7.
8.
omental
M, Hall AD: Computed
tomography
and other mediastinal fatty masses. J Comput Assist Tomogr 1 : 181-1 83, 1977 Muhm JE, Brown LA, Crowe JK: Use of computed tomography in the detection of pulmonary nodules. Mayo Clin Proc 52:345-348, 1977 Jost AG, Sagel SS, Stanley AG, Levitt AG: Computed tomography of the thorax. Radiology 126: 125-136, 1978 Geise RA, McCullough EC: The use of CT scanners in megavoltage photon-beam therapy planning Radiology 124 : 133-141 1977 Cherriak ES, Aodriquez-Antunez A, Jelden GL, Dhaliwal
herniation
.
,
9.
iO.
CANCER
67
Lavik PS: The use of computed tomography for radiatherapy treatment planning. Radiology i17:613-614,
1975 Sontag MA, Implications
corrections
Battista JJ, of computed
in photon
Bronskill MJ, Cunningham JA: tomography for inhomogeneity beam dose calculations. Radiology
124:143-149, 1977 Emami B, Lee DJ, Munzenrider
evaluation
1 . Sagel S, Stanley AJ, Evans AG: Early clinical experience with motionless whole body computed tomography. Radiology 119:321-330, 1976 2. Stanley AJ, Sagel SS, Levitt AG: Computed tomography of
of intrathoracic
LUNG
AS, tion
11.
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1976
14.
MillerWE, CrowJA, MuhmJA: Theevaluation of pulmonary parenchymal abnormalities by tomography. Radio! Clin NorthAm 14:85-93, 1976 15. Castellino RA, Filly A, Blank N: Routine full-lung tomography in the initial staging and treatment planning of patients with Hodgkin’s disease and non-Hodgkin’s lymphoma. Cancer 38 :1 130-i 136, 1976 16. Mink JH, Bein ME, Sukov A, Herrman C Jr, Winter J,
Sample nor
WF, Maider
mediastinum
D: Computed
tomography
of the ante-
in patients with myasthenia gravis and suspected thymomas. Am J Roentgeno! 130 : 239-246, 1978 17. Kreel L: The EMI whole body scanner in the demonstration of lymph node enlargement. Clin Radio! 27 : 421 -429, 1976 18. Sternick ES, Lane FW, Curran B: Comparison of computed tomography and conventional transverse axial tomography in radiotherapy treatment planning. Radiology 124 : 835836, 1977
