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Int Chin J Dent 2004; 4: 34-39.

A comparative study of gallium-67 scintigraphy andcomputerized tomography in the diagnosis of head and necktumors
Ning-yi Li, DDS,a Jian Sun, DDS,a Mu-yun Jia, DDS,a Xiao-ming Jin, DDS,a Wei
Shang, DDS,a and Shu-yao Zuo, DDSbab

Department of Oral and Maxillofacial Surgery, and Department of Nuclear Medicine, Qingdao
University Medical College Affiliated Hospital, Qingdao, P. R. China
Purpose: To compare the effects of gallium-67 (Ga-67) scintigraphy with computerized tomography (CT)scanning in the diagnosis of head and neck neoplasm.
Materials and Methods: Eighty-three patients with neoplasm in head and neck underwent local CT
scanning and Ga-67 scintigraphy preoperatively. The results were verified pathologically after operation.
Results: In total 43 cases of benign neoplasm according to pathological examination, 21 cases (42.5%)
were identified using CT preoperatively, 36 cases (83.7%) were identified using Ga-67 scintigraphy.
Significant difference can be found between Ga-67 scintigraphy and CT scanning in identifying thebehavioral classification of tumors. The remaining 40 cases were malignant neoplasm, and 17 cases(42.5%) were identified or suspected to be malignant using CT scanning, while 37 cases (92.5%) wereidentified using Ga-67 scintigraphy. There was still significant difference between these two methods.
Conclusion: CT shows advantages in identification of tumor size, location, internal structure, and syntopy,
while Ga-67 scintigraphy has advantages in identification of behavioral classification and metastasis oftumors. (Int Chin J Dent 2004; 4: 34-39.)
Clinical Significance: The results of this study demonstrate that Ga-67 scintigraphy is a useful clinicalapproach in tumor diagnosis, especially in identification of behavioral classification of tumors, that is,benign tumor or malignant one, and in judgment of metastasis.
Key Words: computerized tomography, diagnosis, gallium-67, head, neck, neoplasm.

Introduction
Computerized tomography scanning (CT) is an important tool in check and diagnosis of head and neck
neoplasm, especially in identification of size, location and syntopy, which can provide surgeons withinvaluable data and information. However, CT does not give satisfactory results in the identification ofbehavioral classification of neoplasm, that is, benign tumor or malignant one. Clinically, the behavioral
classification of a tumor can be inferred from its position, whether it has an integrated membrane and if it
invades surrounding tissues. Generally speaking, it is difficult to judge the behavioral classification oftumors before they invade surrounding tissues. Although some features such as ample blood supply,
intrusion into surrounding tissues, damage of the blood vessels can be shown by CT images after injectionof meglumine diatrizoate compound, clinicians cannot deduce the actual behavioral classification of tumors
according to these features.
Recently, Ga-67-citrate imaging has been applied to differentiate the behavioral classification of headand neck tumors.1 In malignant tumors, Ga-67 is absorbed to a high extent by tumor cells. After injection,
Ga-67 is mainly bound to transfferin and becomes transfferin-Ga-67 complex.2,3 The complex is delivered
to the tumors through capillaries with increased permeability. The complex then combines the receptors on
the membrane of tumor cell and enters the tumor cell.4,5,6 This imaging method has a high sensitivity in the34

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diagnosis of malignant tumors.7,8,9

Int Chin J Dent 2004; 4: 34-39.

Undoubtedly, Ga-67-citrate imaging as a method of clinicalexamination showed a bright future in tumor diagnosis and the design of therapy strategy against tumor inearly stage. This article compared Ga-67-citrate imaging with CT to observe its applied value in clinicalpractice.

Materials and Methods
Patients
From January 2000 to December 2002, 83 patients with head and neck neoplasm admitted to thedepartment of Oral and Maxillofacial surgery at Qingdao University Medical College Affiliated Hospitalwere entered into this study. Fifty-one patients were male and 32 patients were female. The age ranged
from 16 years to 83 years, and the average age was 48.2 years. The patients underwent examinations using
CT scanning and Ga-67 imaging prior to surgery and the neoplasm specimens were identified
pathologically after operation.
Appliances and Imaging Reagent
A single photon emission computed tomography (SPECT, Model DX, Sophy, Paris, France) equippedwith a low energy all purposed collimator and a matrix of 93 keV energy peak with 20% centered energy
windows was used. An average of 5.0x105 counts/image was selected. In addition, a CT (Model TF4800,Shimadzu Corp., Kyoto, Japan) and a magnetic resonance imaging system (Signa 1.5T MR/i, GE Corp.,
Waukesha, WI, USA) were used. Ga-67-citrate (Kexing Pharmacological Corp., Shanghai, P. R. China)
was employed as an imaging reagent.
Methods
The patients were injected intravenously with Ga-67-citrate of 111-148 MBq. The post-anterior, rightlateral, and left lateral position images were taken using the SPECT appliance 24, 48, and 72 hours afterinjection. The diameters of positive tumors (malignant tumors) were measured using the SPECT special
software. At the same time, the diameter of tumors shown by CT and radiology were measured using theCT accessory ruler. Results of both measurements were compared. The images of the SPECT appliancewere judged to be benign or malignant by two senior doctors according to the following accepted standards,and then were divided into benign group and malignant group according to the results of pathologicalexamination. The comparison between the results of SPECT and CT were done simultaneously.
Diagnostic Standard
Diagnostic standard was defined as follows: positive; the area of lesion had a higher intensity of Ga-67
than that of surrounding area or opposite salivary gland, TC/NC (tumor counts/normal counts)>1.15, andnegative (benign tumor); the area of lesion had the same intensity as the surrounding normal tissue,
TC/NC<1.15.
Statistics
The positive results of Ga-67 imaging and CT scanning were calculated using the chi-square test. Thecomparison of tumor sizes was calculated using the t-test.

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Int Chin J Dent 2004; 4: 34-39.

Results
Comparison between Ga-67 Imaging and CT in Judgment on Behavioral Classification of Tumors
The analysis of benign tumors: 43 benign lesions were confirmed after operation, including 32 benigntumors (12 pleomorphic adenomas, 10 Warthin tumors, eight neurolemmomas, one ameloblastoma, andone fibroma) and 11 inflammatory lesions. The results of CT images showed that 21 out of 43 were benigntumors (48.8%), including six confirmed benign tumors and 15 suspected benign tumors. Twenty-two outof 43 (51.2%) could not be confirmed diagnostically using CT scanning. While Ga-67 imaging showed 36
out of 43 (83.7%) were negative which means that they were benign tumors, Ga-67 also showed seven outof 43 (16.3%) were positive which means that they were malignant but were identified as benign tumors
after pathological examination (five pleomorphic adenomas and two chronic parotitis). The results areshown in Table 1.
Table 1. Comparison of Ga-67 scintigraphy and CT in the diagnosis of head and neck tumors.
Methods
CTGa-67

Benign tumors
Cases Coincident

Disagrement

Malignant tumors
Cases Coincident

Disagrement4343

22 (51.2%)
7 (16.3%)40
40

27 (57.5%)
3 ( 7.5%)

21 (48.8%)
36 (83.7%)

17 (42.5%)
37 (92.5%)

Significant difference was found between CT and Ga-67 for both benign and malignant tumors (p<0.01).

The analysis of malignant tumors: There were 40 malignant tumors (18 squamous cell carcinomas, fivemalignant pleomorphic adenomas, five adenoid cystic carcinomas, four malignant lymphomas, twoadenocarcinomas, two mucoepidermoid carcinomas, and 4 metastatic carcinomas from lymph nodes ofneck) identified using pathological examination.

CT images confirmed five malignant tumors andsuspected 12 malignant cases, total 17 cases (42.5%). The remaining 23 cases cannot be confirmed(57.5%) using CT. Thirty-seven cases showed positive images using Ga-67 imaging and confirmed to bemalignant (92.5%), three cases showed negative (7.5%). Squamous cell carcinoma, lymphoma, lymph
node metastatic carcinoma, and mucoepidermoid carcinoma showed 100% positive results using Ga-67
imaging while two malignant pleomorphic adenomas and one adenoid cystic carcinoma showed negative
results (Table 1). A 41-year-old male patient, who had had a tumor in his left parotid gland for threemonths, was scanned using CT, which showed as an inflammatory lesion. However, results from theSPECT appliance showed a high accumulation of Ga-67 in the same area, which indicated that it was amalignant tumor. This Ga-67 imaging result was confirmed by pathological examination after operation(Figs. 1 and 2).
Comparison of the Image Characteristics of Ga-67 Imaging and CT Scanning
There was no significant difference between the two groups in the measurement of head and neck tumor
size (Table 2). CT showed its obvious advantage in showing syncope and outline of tumor tissues,36

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Int Chin J Dent 2004; 4: 34-39.

especially its relations to main vessels. CT images can demonstrate clearly the internal structure of thelesions, such as liquefaction or abscess, while Ga-67 images cannot. Furthermore, a relatively large
abscess will not be detected using Ga-67 imaging.
Table 2. Comparison of Ga-67 scintigraphy and CT in measuring size of head and neck tumors.
Size (mm)

Cases

Ga-67

CTT-value

P-value

0.0-2.0
2.1-4.0>4.01122102.17 (0.51)
2.83 (0.41)
5.74 (0.96)

1.84 (0.26)
2.79 (0.28)
6.73 (1.30)

1.28
0.26
1.76

p>0.05p>0.05p>0.05

Standard deviation (mm) in parentheses.

1
Frontal view
2
Lateral view
2Fig. 1. CT showed left parotid gland benign tumor, and were diagnosed as malignant
pleomorphic adenoma by pathological examination.
Fig. 2. Ga-67 showed malignant tumor of left parotid gland, were diagnosed as malignant
pleomorphic adenoma by pathological examination.

Discussion
Judgment of Size, Morphology, Syntopy of Tumors
Both CT and Ga-67 imaging can indicate tumor size. No difference was found through using these twomethods (p>0.05). However, a few tumors displayed different sizes when imaged by these two methods,
which was related to the volume and position of tumors. If excessive amounts large/small tumors had beenpresent, more obvious difference between these two methods would be detected.10 In general, CT had moreadvantages than Ga-67 imaging in respect to size, outline, internal structure and syntopy of tumors,
especially to malignant tumors invading surrounding tissues. Therefore, CT scanning can help surgeons todetermine the dissection range and make an appraisal of the operation risk.
Judgment of Behavioral Classification of Tumors
In our study, positive results were found in 92.5% malignant tumors, especially, in 100% squamous cell
carcinoma and lymphoma, whereas false-negative results were also found in malignant pleomorphic
adenomas and adenoid cystic carcinoma. Similar result was reported in Murata’s study.11 While only37

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Int Chin J Dent 2004; 4: 34-39.

42.5% malignant tumors can be showed by CT images. There was a significant difference in this study
between these two methods.
The accumulation of Ga-67 can also be found in an inflammatory lesion.12,13

It is difficult todifferentiate them from tumors,14 but if it is an inflammatory lesion the intensity of Ga-67 will reduce
rapidly 48 hours after injection whereas it reduces slowly in tumors. We found that the imaging outline of
the inflammatory lesion was indistinct and bigger than the actual lesion. In some cases, the duct of thegland was intensive and clear, while similar features were not found in malignant tumors. In the group ofchronic inflammatory lesions, two out of 11 cases (18.2%) showed positive results, which was not a highrate. Hyperplasia of fibro-connective tissue, atrophy of gland and decrease of quantity and permeability ofvessels in the negative growths can be identified by pathological examination. So, chronic inflammatory
lesion in this study was not identified at a high positive rate as documents had reported.14
The five cases of pleomorphic adenomas also showed positive results and seven cases showed negativeby Ga-67 images.

Similar result was reported in Shinohara’s study.15

Yoshikai et al.16 stated only

pleomorphic adenomas showed positive Ga-67 imaging using the technique of DNA fluorescence staining,which was confirmed by pathological examination.

This suggested that the active epithelial cell ofpleomorphic adenomas might be responsible for the Ga-67 uptake, but the pleomorphic adenomas withmany mesenchymal cells showed negative results.

Therefore we should pay more attention todifferentiating pleomorphic adenoma from malignant tumors.
Judgment of the Nature of Lymph Nodes of the Neck
Only 20% head and neck malignant tumors of cN0 stage were identified as lymph node metastasis using
pathological examination after operation. If all the patients underwent surgery of the neck, about 80% ofpatients will be subject to unnecessary operation and suffer from the complications of an operation.
Furthermore, radical neck dissection will cause patients shoulder syndrome.17 So, it is important to judge
the metastatic conditions of the lymph nodes of the head and neck before deciding to operate. Ga-67
scintigraphy can give reliable information on the risk of recurrences in the soft tissues of the neck.18 In thisstudy, positions and sizes of three lymph node metastatic carcinomas were identified using CT scanning,but the metastatic conditions of these lymph nodes cannot be identified positively. While all the threemalignant tumors showed positive results in Ga-67 images, which were correlated well with pathologicaldiagnosis. Clearly the Ga-67 imaging has more value in the diagnosis of the metastatic carcinoma.

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Reprint request to:
Dr. Ning-yi Li
Department of Oral and Maxillofacial Surgery
The Affiliated Hospital of Medical College, Qingdao University
16 Jiangsu Road, Qingdao, Shandong province, 266003, P. R. China
Tel: +86-532-2911342 E-mail: Liningyi342@qingdaonews.com
Received October 2, 2003. Revised February 25, 2004. Accepted March 2, 2004.
Copyright ©2004 by the Editorial Council of the International Chinese Journal of Dentistry.

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