Technetium-99m Pertechnetate Salivary Gland Imaging: Its Role in the Diagnosis of Warthin's Tumor

Case Presentation and Discussion: Gregory S. Weinstein, Robert T. Harvey, Wayne Zimmer, Suat Ter and Abass Alavi

Fmm the Case Reports ofthe Hospital ofthe University of Pennsylvania

cinoma of the lung. No furtherinterventionwas considered nec JNucIMedl994;35:179—183 essaiy for the parotidmasssinceit was confirmedto be a benign lesion and did not cause significantdiscomfort.

CASE PRESENTATION DISCUSSION A 74-yr-oldmalecomplainedof painlessswellingin the right parotid area which started several months ago. There was no Pre-operative diagnosis of a Warthin's tumor is of con associated numbness in the area, and he denied facialweakness. siderable value in the evaluation of patients with parotid Essentially, the masswas asymptomatic. His past medical history gland swelling. In this case, the benign nature of the parotid wasunremarkableandhehadnopriorsurgery.Hewasnotonany tumor allowed the attending physicians to concentrate medications. He denied allergies. He had smoked tobacco, two their effortson the managementof lung cancer. The useof packs a day for 55 yr and quit 6 yr prior to the current medical parotid radionuclide scanning with [@Tc]pertechnetate problem.He didnotdrinkalcohol. greatly facilitated the pre-operative evaluation of this pa. Physicalexaminationrevealeda well developedman in no tient's presenting complaint. acute distress. He had no head and neck abnormalities except for Technetium-99m-pertechnetate was first used for brain a right-sided 2 x 3-cm parotid mass. A fine needle aspiration was performedduring the initial visit. and thyroid scanning in the early 60s (1,2). Its use for An MRI scanrevealeda largerightparotidmass,measuring3 parotid gland imagingwas realized incidentally while im cminitsgreatestdimensionwithintheinferioraspectofthegland. aging the brain (1,2). Grove and DiChiro were the first to Two otherincidentalfindingswere alsonoted.The firstwas a study the salivary glands with [@Tc]pertechnetate (3). rightcerebellopontineangletumor,andthesecondwastwo en Manyreportshave appearedin the literaturesubstantiating hancinglesionswithinthecerebellum,bothsuspiciousfor meta the role of this imaging technique in the management of static disease. Fine needle aspiration cytology of the parotid mass patients with parotid gland disease and especially with revealednormalparotidaciniandafewoncocyticcellsassociated Warthin's tumor (4—12).We hope to lend additional sup with numerouslymphoid cells, consistentwith Warthin's tumor. port for this effective diagnostic study, which may have No evidenceof malignancywas found.Becauseof the incidental since lost popularity in favor of fine-needle aspiration. detectionof massesin the head, it was decidedto initiatea Warthin's tumor (papillary cystadenoma lymphomato workupto locatea primarytumor.In addition,a radionuclide sum), a benign neoplasm of the majorsalivaryglands (par scan to assess the nature of the parotid mass and to confirm its benign nature was also scheduled. ticular the parotid gland), was described in 1910 by two A radionuclidescanof the parotidglandwas performedfollow German physicians, Albrecht and Arzt (13). The first En ing the intravenousadministrationof [@Tc]pertechnetate (Fig. glish cases were described as adenomas of heterotopic 1).A SPEC!' scan of the head was also obtainedas part of this salivary glands in the preparotidlymph nodes by Nichol examination.The imagerevealedan areaof increasedfocal up son in 1923 (14). This tumor has a varied nomenclature takeintherightparotidgland,consistentwiththepatient'sknown including adenolymphoma, papillary cystadenoma lym Warthin's tumor. No posteriorfossa uptakewas noted. A chest phomatosum, lymphomatous adenoma and oncocytoma, x-rayrevealeda rightupperlobemass,suggestingcarcinomaof but the termWarthin'stumorhas been extensively used to thelungandchronicobstructivepulmonarydisease.At thispoint, credit Aldred Scott Warthinwho published the first two thepatientwasreferredfor definitivetherapyfor metastaticcar case reports in the American literaturein 1929 (15). War thin's tumor is the second most common benign parotid ReceivedOct.11,1993;revisionacceptedOct 11,1993. tumor (benign mixed tumors are the most common), and ForcorrespondenceandreçX1ntSCOnta@AbassPJa@,M.D.,DMSbnOfNUdear MedIcine,Departmentof R&ik@Ogy,Hospftaiofthe Un@iersftyof Penns@1vania,I classically accounts for 2% of all head and neck tumors and DonnerBldg.,3400SpruceSt, Philadelphia.PA19104. 6%—lO%of parotid gland epithelial tumors (4—6,16—20).

[@TcJPertethnetate Salivary Gland Imaging •Weinstein et al. 179 lung cancer deaths among women in an age-matched co hort. In this study, 82%of the female patientswere smok ers. Given that the parotid duct epithelium is in direct continuity with the oral cavity, they postulated that orally inhaled tobacco smoke may play a role in ductal epithelial metaplasia leading to tumor formation (22). The peak incidence of Warthin's tumor is frequently

PIGHT LEF observed in the sixth and seventh decades (4,6,18,21). As alludedto earlier, the overwhelmingmajority of Warthin's tumors are benign, and malignant transformationis rare. Carcinomas arising from this tumor have been estimated at 0.3% of all lesions (16). Grossly, the tumor is round or oval, encircled by a thick capsule. It rarely infiltrates the surrounding gland. The surface is pink-grayin color, smooth or lobulated (17,19). The histologic diagnosis of Warthin's tumor requires the @ 1@ri, ,‘ 1::4@ presence of an epithelial parenchyma and a lymphoid FiGURE1. Technebum-99m-peitechnetatescan acquiredin stroma, distinguishing it from an oncocytoma (4,5,16,17). @edor,antenorandbothlateralprojectionsrevealedincreased The parenchyma is organized in a tubulopapillaiy-cystic focaluptakeinthe lowernghtparotidgland.Thiswas interpretedto pattern and features epithelial cells with numerous mito be consistentwithWarthin'stumor. chondria, surroundingdilated cystic spaces of secretory material,which is clear, serous, milky, mucoid or choco late in color (17). The epithelium lining of the cysts is There are reports, however, of highincidences, citing 14%, usually a double layer of cells with papillary projections 14.4% and even 24.4% of all parotid tumors (5,16,17). into the cysts. The inner layer consists of tall columnar Warthin's tumor is the most common salivary tumor to cells with a dense oxyphilic granularcytoplasm due to an be bilateraland multifocal (11,16). Chapnikobserved 12% abundance of mitochondria (4,17,19,21). These cellular of patients developing more than one lesion, which can changes (referredto as oncocytic changes) commonly oc manifest as multiple, discrete prhnaiy lesions occurring cur with aging and their significance is not known, though within one parotidgland(4). Numerous other reportshave they are implicatedin the neoplastic process (4). The outer identified a bilateral incidence of 3%—8%of cases, while layer consists of rounded or cuboidal cells. There is wide 4%—12%are multifocal (8@19,21,23). Finkeistein et al. re variation regarding the extent of cyst formation and cyst ported a case of Warthin's tumor presenting as multiple contents, the degree of epithelial metaplasia, and the pro bilateral synchronousparotid masses,which is believedto portion of lymphoid stroma to epitheium (4,8,17,21). A be the third such casein the literature (8). Additionally, basement membrane separates the epithelium and lym Warthin's tumor has a postoperative recurrence rate of phoid stroma, which supports the epithelial parenchyma 6%—i2%(16,23) which may result from a high frequency of andhasbeenfound to containgerminalcentersalongwith undiagnosed multifocal lesions at the time of original sur stem cells, lymphocytes, plasma cells, mast cells, histio gery (11). cytes and macrophages (4,8,17). The origin of lymphoid Clinically, Warthin's tumor is very slow growing and stroma has been debated, as will be discussed below. may even appear static over many years. It commonly Paralleling the tumor's interesting histologic composi presents as an asymptomatic painless swelling at the lower tion is its histogenesis,which is based on the fact that pole of the parotidgland for many months (8,17,18,21,22). lymph nodes are contained within the normal mature pa Chapnik reported a range from 3 wk to 10yr (4). The facial rotid gland. During development, the salivary tissue of the nerve is usually spared, as nearly all cases are benign expected parotid gland intermingles with the neighboring (8,16). The majority of tumors are 1—3cm in diameter, well lymphoid tissue of expected lymph nodes. As these tissues circumscribed, and encapsulated. Fluctuations in tumor mature, they remain in close proximity of the gland. The size do not appear to occur (4,21,22). Historically, War matureparotidgland is encircled by a capsule, but encap thin's tumor has demonstrateda predilection for males, sulationoccurslate in developmentandresultsin intrusion andthe literatureconsistently cites male-to-femaleratiosof of lymph nodes into the parotid gland, and invasion of the at least 5:1 (4,6,23). However, recent reports have docu peri-parotidlymph nodes with salivary duct tissue. Thus, mented changes in the male versus female distribution, such elements become a diagnostic component of the tu with equal incidence in both sexes since the mid 1970s mor(4,8,21,23). Neoplastic transformationofthe heteropic without explanation.Male-to-femaleratios of lessthan 2:1 salivary gland tissue trappedwithin lymphoid tissue may are quite common (7,18,21,22). Lamelas et al. found that be responsible for the formationof these tumors (4). This the increasing incidence of Warthin's tumor in women developmentalprocess leads to several observations, most paralleled similar increases in tobacco consumption and notably, (1) the presence of ductal tissue within lymphoid

180 TheJournalof NuclearMedicine•Vol.35•No.1 •January1994 tissue; (2) the location of almost all Warthin's tumors in the facial nerve). However, this procedure also has some lymphatic tissue within or adjacent to the parotid gland; limitations in that the specimen may not be representative and (3) the multifocal nature of the tumor (8,23). of the acturallesion andthereforeanerrorin diagnosismay Debate exists over the role of the lymphoidtissue in this be made (4). Additionally, the facial nerve may be injured tumor. during aspiration of a parotid gland mass. Lindberg and Some believe it is a cellular response to epithelial neo Akerman have reported that fine-needle aspiration cytol plasia, and others believe it is a normal lymph node sur ogy can be used to achieve a positive preoperativediagno rounded by epithelial proliferation. Studies have demon sis in 81%of specimens, while yielding 8% false-negative strated that both T and B lymphocytes are contained within results (24). Their false-negative rate was reduced to under the lymphoid stroma, which may indicate that the tumor 5% when the biopsy and cytology were performed by cx may have originated in pre-existing lymph nodes. Others perienced individuals. An 11% nondiagnostic rate could have found functional germinalcenters and an abundance not be reduced because of the cystic nature of the tumor of IgA plasma cells in Warthin's tumors, suggesting an (24). X-ray studies (plainfilms and CT scans) provide some immune response to the tumor. It has also been shown that diagnostic information (e.g., size of lesion, extension, most Warthin's tumors have excessive amounts of lym etc.), but lack detailed analysis (e.g., cystic or solid). Ra phoid tissue compared to normal lymph nodes. Nonethe dionucide imaging with [@“FcJpertechnetatehas been less, most authors believe that the majority of Warthin's shown to provide some useful specific information about tumors develop from heterotopic salivary ducts within pre certaindisorders, and can also reflect alterationsin normal existing lymphoid tissue, which undergoes subsequent re physiological function (5). active changes in response to the neoplastic epitheium Radionuclide scanning with [@Tc]pertechnetate is a (4,21 ). In contrast, the submandibular and sublingual simple and noninvasive method for assessing salivary glands develop independently of lymphoid tissue, and are glandfunction. It is a suitable radioactivetracerfor human encapsulated early. Their developmental process pre use because of its short half-life of 6 hr and pure gamma cludes intermingling of salivary and lymphoid tissues, thus emission of 140keV, which is readilydetected by a gamma limiting Warthin's tumor to the parotid gland and its im camera(4). Thetechniqueiswell describedin theliterature mediate environment (11). (4,5,10) and involves imaging of the parotid gland in the Diagnosis of Warthin's tumor based on clinical assess posterior projection after the intravenous infusion of 5 mCi ment is questionable since the tumor is indistinguishable of the tracer at 60-secintervals for 20 min and obtaining from other benign lesions of the parotid gland (17). A final images of the patient in water, right lateral and left variety of tissue analyses and imaging techniques have lateral positions, followed by washout images obtained 3 been employed in an attempt to arrive at the correct diag min after stimulationwith orally administeredlemon juice nosis, and such methods include plain radiographs,sialog to determineadequacyand symmetiy of glandularsecre raphy, [@TcJpertechnetate scanning and tissue biopsy. tion (6). Sialographyis useful for evaluatingthe ducts andparen Salivary imaging with a gamma camera interfaced to a chyma of the parotid glands, which also may suggest the computerallows rapidsequentialimages andassessment of presence of a tumor as evidenced by displayingthe effects the three distinct phases: blood flow (uptake), functional on the ductal system (stretching and displacement without (concentration and storage) and washout (drainageof the duct destruction) (4,5,21). Since this finding is common tracer) (4,5). The activity is compared with the normal among all benign parotid gland neoplasms, its presence is tissue surrounding the lesion during these phases, and not specified as Warthin'stumor. Malignanttumors more one ofthree patternsis noted; “cold,―“warm,―or “hot.― commonly show invasion and destructionof the ducts (5). A scan is cold if the lesion does not concentrate Thus, the study is limited and therefore should not play a [99mTc]pertechnetate as much as the normal gland. A scan major diagnostic role in this regard (4,17). The combina is warm if the uptake is similarbetween the lesion and the tion of sialography and CT scanning may be more reliable normaltissue. A scan is hot if the lesion displays increased than sialography alone in identifying small tumors, deter [@TcJpertechnetate uptake (4). mininglocation of tumor, assessing invasiveness and iden Neoplasms and inflammatory lesions are distinguished tifying intrinsic and extrinsic lesions (4,19). This analysis from avascular lesions (e.g., cysts), and glandularatrophy can be furtherenhanced with the adjunctive use of intra based on the activity in the initialblood flow phase: Blood venous administration of contrast, particularly if the lesion flow is increased in the former, and decreased in the latter is a vascular tumor (4). group. The functional phase is analyzed for increased or Controversy surrounds the use of needle biopsy and decreased function: Nonfunctioning lesions are usually aspirationof salivaryglandlesions. Needle biopsy is useful suggestive of carcinoma, mixed tumors or cysts, whereas in that a tissue specimen is procured upon which a histo hyperfunctioning intrinsic lesions frequently represent logic diagnosis may be conferred. If a Warthin's tumor is Warthin's tumors. Oncocytomas which are ectopically 1— identified, surgery may be avoided in high-risk patients or cated are also functional. A normalwashout phase is char the surgical approachmay be tailored for adequate resec acterized by accumulation of radioactivity within the oral tion of the mass thus sparing neighboring structures (e.g., cavity following a secretory stimulus. Delays in this drain

[@Tc]Pertechnetate SalivaryGland Imaging•Weinsteinet al. 181 age pattern may result from obstructed glands, whereas obstruction of the parotidgland, or from stasis or pooling local retention within the gland is strongly supportive of a of secretions within dilated acini and ducts as in Sjogren's Warthin's tumor. This pattern is quite typically seen with syndrome. Additionally, a normal gland could be inter Warthin's tumor because the tumor is capable of concen preted as a hot gland if the contralateralparotid gland is trating the tracer, but cannot secrete it since the tumor nonfunctioning (4). Acute parotitis was also found to mim does not communicate with the gland's ductal system ick Warthin's tumor in that both produced a hot uptake (4,5). scan. However, the two conditions differedin the washout Classically, two parotid neoplasms yield a hot [@Tc] scans, again reinforcing the importance of performing the pertechnetate scan; Warthin's tumor and oncocytoma. final phase in order to detect Warthin's tumor (9). Some pleomorphic adenomas can appear with mildly in False-negative scans indicating a lack of sensitivity have creased uptake of [@‘Fc]pertechnetate, but the remaining also been reported (4). Not all Warthin's tumors actively benign tumors do not (4,6,11). However, Abramson et al. concentrate [@‘Tc]pertechnetateto a higherlevel thanthe found that only the Warthin'stumorwas able to produce a surrounding normal tissue. In this instance, the washout truly hot scan (25). The increased uptake of phase assumes even greater importance in detecting a tu [@Fc]pertechnetate by Warthin's tumor and oncocyto mor since the tracerwill wash out of normalparotidtissue mas is due to epitheium contained within these tumors (5). Additionally, some Warthin's tumors will display a which can extract large anions from the blood (such as mixed washout patternas has been definedby Sostre et al.: pertechnetate). There is, however, a subtle difference in homogeneous (evenly hot), nonhomogeneous (alternating the way the Warthin'stumor and the oncocytoma concen hot and warm areas) and mixed (hot and cold areas). The trate [@“Tc]pertechnetate.An oncocytoma concentrates classic homogeneously hot pattern was seen in 44% of the radionucide within the proper tumor cells, whereas a patients. Nonhomogenous andmixed lesions were found in Warthin's tumor will concentrate the radionucide within 22% and 33% of patients, respectively. These latter scan the tumor mass and thus will not demonstrate a cavitaiy patterns resulted from cystic inclusions within the tumor appearance as might the former (4). Additionally, multifo mass. Large cysts produced a mixed scan pattern and cality does not occur with oncocytoma, which may help in multiple smallcystsproduceda nonhomogeneouspattern. the differentiationof these two similartumors (9), but this In contrast, those patients with a homogeneous pattern had has been disputed (4). mucoid or mucopurulent material within the tumor and As stated, Warthin's tumor does not communicate with noticeably lacked cystic formation (12). Mishkin indicates the ductal system, allowing the accumulated [@‘Fc] that patients with focal swellings (inflammatoryor meta pertechnetate to remain in the gland without being Se static foci, cysts and abscesses involving the glands) may creted. Therefore, the washout images are very important not benefit from radionucide scanning since they are non in diagnosing Warthin's tumor, because this tumor is not functioning (10). Radionucide scanning however, may be capable of secreting the tracer whereas both normal pa able to determine the underlying cause in diffuse parotid rotid gland and most other parotid abnormalities drain gland swellings, which includes parotitis, functional or me upon stimulation. Thus, a washout patternthat shows un chanical obstruction due to major duct occlusion or duct changed or even increased pattern of activity is quite abnormalities, as well as infiltration of the lobules by lyin unique for Warthin'stumor (6). phocytes. He stated that [@‘Fc]pertechnetate scanning of Several authors have reported successwith [@“Tc]fers an excellent functional image of the salivary glands, pertechnetatescanning. Chapniknoted 10/10patients with but is not always specific for Warthin's tumor and inter Warthin's tumor to have a positive scan (4). Elledge and pretationof a scan relies on humanjudgment (10). Moss found the scan very predictive in their series of 23 patientswith Warthin'stumor(7). Higashiet al. (6) andLu et al. (9) also reportedsuccess in 5/5 and 4/4 patientswith CONCLUSION Warthin's tumors, respectively. Sostre et al. found that the Surgery is considered curative in the management of washout scan successfully identifiedWarthin'stumorsin 9fl) patients with Warthin'stumor. Since the tumor is usually patients(12). Despite thiswidespreadsuccess with radionu well-defined and superficial, its removal is easily achieved. cide scanning,there are reportswhich disputeits routine However, if incompletely removed, or if detected foci re application,claimingthatsalivaryglandimaginglacks sensi main after the original surgery, tumor recurrence is cx tivity and can detect only clinically apparent mass lesions; pected (5,17). Approaches to the removal are based on [@FcJpertechnetate scanning is nonspecific for Warthin's tumor size and location, and include limited resection, tumor; salivary gland function is incompletely understood; superficial and deep lobe parotidectomy. Usually, the fa and protocols for salivary gland imaging are cumbersome cial nerve is spared (4). The literature has shown, as has andoftendiscouragenuclearmedicinelaboratoriesfrom car this report, that tumor assessment can be enhanced by iying out such studies (10). performing [@FcJpertechnetate radionucide scanning. False-positive scans indicating poor specificity have From a surgical perspective, these scans are extremely been reported. Not all hot nodules are Warthin's tumors useful. Greyson and Noyek firmly believed that the pre (4,6,10,19). False-positive scans may result from partial operative diagnosisof a functional parotid gland tumor

182 TheJournalof NuclearMedicine•Vol.35•No.I •January1994 indicates a Warthin'stumor, and given its benign nature, a Warthin'stumorwith technetiuin.99mpertechnetate.ClinNuciMed 1987; less aggressive surgical approachwould be indicated (5). 12:796—800. 7. ElledgeES,MossJ. Papillaiycystadenomatymphomatosum(Warthin's Frequently, patients who are in the sixth and seventh de tumor)achan@ngincidence?EarNoseThorati 1990;69:732-736. cadesof life haveconfoundingmedicalproblems,andmay 8. FinklesteinDM,NoyekAM,ChapnikJS.Multipkbilateralsynchronous not be able to tolerate the rigors of surgery. It would be Warthin'stumors:a case reportand reviewof the literature.I OtOIWyngOI 1989;18:357—361. unjust to remove a parotid gland mass in these patients, 9. Liuas, YehSH,YenIC, HsuDF.SalivaiySCintigraphywithvitaminC only to discover that it was a benign tumor. We believe that stimulation:an aid in differentiatingunilateralparotitisfrom Warthin'stu such a scenario could be avoided with the use of mor. EUrINUC! Med 1990;16:689-691. 10.MishkinFS.Radionuclidesalivaiyglandimaging.SeminNuciMed 1981; [@“Fc]pertechnetatescanning. Clearly it would be more 11:258-265. appropriate in such instances to periodically monitor the 11. ShugariM, Som PM, BilIerHF. Warthin'stumor, a multifocal disease.Ann tumor's courseand behavior. OtoiRhinolLwy@goI1982;91:246—249. The combinationof afine-needleaspirationindicativeof 12.SostreS,MedianL, DeArellanoOR.Thevariousscintigraphicpatternsof Warthin'stumor. Cli, NuciMed 1987;12:620—626. Warthin's tumor plus a radionucide scan virtually con 13. Albrecht H, Ant L Beitrage zur Frage der Gewebsvenrrung. Papillare firms the presence of a benign Warthin's tumor. This is Cysadenome in Lymphdrrusen. Frankfurt Ztscbrl. path:1910;41-17. diagnostically acceptable and allows the surgeon to then 14.NicholsonOW.Studiesintumorformation.Guy'sHospRep1923;73:37. 15.WaithinAS.Papillaiycystadenomalymphomatosum.A rareteratoidofthe make a sound decision and to avoid surgery in patients in parotid region. I CancerRes 192913:116. whom it is safe to follow these slow-growing tumors. An 16.BatsakisJO.Carcinomacx papillalycystadenomalymphomatosummalig elderly patient of 70 yr with a 3-cm mass in the parotid nant Warthin's tumor. Ann Owl Rhino! La,yngol 1987;X:234—235. gland can easily be followed for the remainderof his life if 17. @haudiyAP, GorlinRi. Papillaiycystadenomalymphomatosum(ade nolymphoma): a review of the literature. Am I Surg 1958;95:923-931. surgery is precluded for other reasons. Therefore, it be 18.KennedyTL.Warthin'stumor:areviewindicatingnomalepredominance. hooves the surgeon and the nuclear medicine physician to Lwyngoscope 1983;93:889—891. work together to provide the most sound approach in pa 19.MiksanekT,ReyesCV,BorkenhagenR.Warthin'stumor.AmFamPhys 198327:157—160. tients with suspectedWarthin's tumors. 20. Rubio PA, Farrell EM. Superficial solid and deep cystic independent War thin's tumorsof the parotidgland.hit Swg 1981;66:279. REFERENCES 21. EvesonJW,CawsonRA.Warthin'stumor(cystadenolymphoma)of sali vai)rglands:aclinicopathologicinvestigationof278cases.OnilSwg 1986; 1. McAfeeJO,FuegerCF,SternHS,WagnerHM Jr, MigitaT. Technetium. 61:256—262. 99m-pertechnetatefor brain scanning.INuci Med 19645:811-827. 22. Lamelas J, Teriy iii, Alfonso AE. Warthin's tumor: muhicentiicity and 2. Harper PV, Lathrop KA, JiminezF, Fink R, OOttSChaIICA. Technetium. increasing incidence in women. Am I Surg 1987;154:347-351. 99mas a scanningagent.Radiology1965;85:101. 23. HeHerKS, AttieJN. Treatmentof Warthin'stumorby enucleation.AmI 3. Grove AS, DiChiro 0. Salivazy gland scanning with technetium.99m Surg 1988;156:294-297. pertechnetate. Ant I RoentRenol 1968;R@2:109—116. 24. Lindberg LO, Akerman M. Aspiration cytuIo@j@of salivaiy gland tumors. 4. ChapnikJS.Thecontroversyof Warthin'stumor.Lwyngoscope1983;93: Diagnostic experience from six years of routine laboratory work. Laryngo 695—716. scopu 1976;86:584—594. 5. GreysonND,NcyekAM. Radionuclidesalivaiyscanning.I Otolaiyngol 25. Abramson AL, Levy LM, Goodman M, Attic JN. Salivary gland scinti 1982;10(suppl):3-46. scanning with technetium-99m-pertechnetate. Laryngoscope 1969;1105- 6. HigashiT, MurahashiH, IkutaH,MotiY,WantanabeY. Identificationof 1117.

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