Efficacy of Administering Simultaneous Oral Perchlorate and 99 Intravenous m Tc04 - for Brain Scanning Mary E. Maxwell and Bonnie J. Baggenstoss St. Paul-Ramsey Hospital and Medical Center, St. Paul, Minnesota Brain scans were performed using the following TABLE 1. Methods of Perchlorate Administration methods: (A) oral administration of perchlorate at least 30 min before i.v. injection of 99mTc-pertechnetate Number of Group Method studies (99mTc04 -) and (B) simultaneous administration of oral 99 perchlorate and i.v. mTc04 -.The scans were retrospec­ Treat with perchlorate at least 30 min 1,558 tively reviewed for choroid plexus uptake of technetium before i.v. injection of 99mTc04 2 Simultaneous administration of oral 1,233 and scan quality. The simultaneous administration of oral perchlorate a·nd i.v. 99mTc04 99 perchlorate and i.v. mTc04 - is an effective method of 3 No perchlorate given ___!Q performing brain scans and should replace outdated pro­ Total 2,938 tocols requiring treatment with perchlorate before i.v. administration of pertechnetate. The syrup was prepared by (A) dissolving the sodium Most nuclear medicine laboratories use a brain scan perchlorate in distilled water, (B) dissolving the para­ protocol that requires the administration of a per­ hens in ethyl alcohol, and (c) adding the alcohol/ chlorate treating agent, either sodium or potassium, paraben solution to the aqueous sodium perchlorate and 99 before the i.v. administration of mTc04 -. The pre­ bringing the combination to the appropriate volume treatment plan requires an expenditure of extra time with cherry syrup. The final solution should be refrig­ and effort for both technologist and patient. The erated to insure stability and increased palatability. primary purpose of this study was to determine if oral The brain scans were arranged into three groups blocking agents administered simultaneously with i.v. according to the method of perchlorate treatment 99 mTc04 - would effectively block the choroid plexus. (Table 1). The scans were performed on either a recti­ linear scanner or a scintillation camera at 45-120 min 99 Materials and Methods after the injection of mTc04 -. All of the 2,938 scans were subjectively evaluated to Brain scans performed on 2,938 patients at St. Paul­ ascertain the presence or absence of choroid plexus Ramsey Hospital were retrospectively reviewed to 99 activity and overall scan quality. assess mTc04 - uptake in the choroid plexus. A per­ chlorate treatment method was used on 2,791 of these patients. The remaining 147 brain scans were performed Results without any perchlorate treatment because of the Brain scans performed after the. simultaneous 99 patients' inability to ingest oral medications. Twenty­ administration of oral Cl04 and i.v. mTc04 - were com­ 99 three of the patients received mTc-DTPA, which does parable to scans performed using a Cl04 pretreatment 99 not require treatment with perchlorate(/). before administering the i.v. mTc04- (Fig. I). There The choroid plexus blocking agents used were either was no evidence of pertechnetate uptake in the choroid 250-500 mg potassium perchlorate (KC104 ) in capsule plexus on any of the studies reviewed in the perchlorate­ form or 500 mg sodium perchlorate (NaC104 ) in a treated series. cherry syrup solution made in the hospital pharmacy When no oral blocking agent was used (147 scans), and consisting of the following: sodium perchlorate, 50 gm; methyl paraben, 2 gm; propyl paraben, 0.2 gm; ethyl alcohol USP, 8.3 ml; distilled water, 500 ml; and For reprints contact: Mary E. Maxwell, Div. of Nuclear Medicine, cherry syrup added to bring the total solution to 1,000 St. Paul-Ramsey Hospital and Medical Center, St. Paul, Minn. mi. 55101. 138 JOURNAL OF NUCLEAR MEDICINE TECHNOLOGY FIG. 1. Brain scans of same patient demon­ strate comparable overall quality and no evidence of choroid plexus uptake. (A) Simultaneous oral 9 perchlorate and i.v. 9 mTc04 - method and (B) 30- min pretreatment with perchlorate before adminis­ tration of i.v. 99mTc. FIG. 2. Brain scans demonstrate increased area of activity in choroid plexus due to patient"s in­ ability to ingest oral perchlorate. (A) Right lateral. (B) posterior. (C) left lateral. and (D) anterior views. 62% (124) demonstrated increased activity in the region that received oral KCI04 before the intravenous 99 of the choroid plexus (Fig. 2). mTc04 -. Qualitative and quantitative analyses of their work showed that the simultaneous administration method was equally as effective as the perchlorate pre­ Discussion treatment method, and that, if indicated for human use, This study has demonstrated that oral perchlorate the simultaneous method could effectively eliminate the 99 and i.v. mTc04 - can be administered simultaneously pretreatment methods currently used. without compromising scan quality. The ability of the Some observers have found that without perchlorate 99 perchlorate ion to effectively enhance brain scan images blockage, uptake of mTc04 - in the choroid plexus oc­ is well documented but not well understood (2-5). Re­ curred in only l-10% of the population (6). This study sults of this study support the findings of Harper, et a! revealed a 62% incidence of choroid plexus uptake of 99 (2) who did a comparison of concentration ratios of mTc04 - when perchlorate was not administered 99 mTc04 - following i.v. injection in dogs. Their study (Table 2). consisted of a control group that received only Technetium-99m-DTPA may be used as an alternate 99 intravenously injected mTc04 -,a group that received a radiopharmaceutical when the patient cannot ingest 99 mTc04 - fNaCI04 solution intravenously, and a group perchlorate. This radiopharmaceutical combines the VOLUME 3, NUMBER 3 139 waiting period for outpatients was reduced by a factor TABLE 2. Qualitative Data on Patients Receiving of 2. i.v. 99mTc04 without Perchlorate Scan Number of finding studies Acknowledgment Uptake in the choroid plexus region only 33 We wish to thank Robert R. McClelland for his help Pathology identified outside choroid plexus region as well as choroid plexus activity 31 with the preparation of this manuscript. Choroid plexus uptake and/or pathology in the choroid plexus region 13 No choroid plexus or pathologic activity 47 Total 124 References I. Hauser W, Atkins HL, Nelson KG, et al: Technetium-99m DTPA: A new radiopharmaceutical for brain and kidney scanning. physical properties of the radionuclide 9*Tc0,- and the Radio1og.v 94:679-684, 1970 2. Harper AG, Friedman BI, Avis KE, et al: Perchlorate blocking biologic properties of chelating agents, which do not of 99mTc0,- uptake by simultaneous intravenous injection in dogs. J concentrate in any organs (1). The use of 99mTc-DTPA Nucl Med 13:363-366, 1972 in brain scanning eliminates a major source of error in 3. Hirsch JI, Sharpe AR, Garnett W: The role of potassium interpretation in the choroid plexus region on brain perchlorate in 99m technetium brain scanning. Drug Intelligence and scans. Clinical Pharmacy 5:252-257, 197 1 4. Oldendorf WH, Sisson WN, Iisaka Y: Compartmental redis- Experience at this hospital indicated that overall tribution of 99mTc-pertechnetatein the presence of perchlorate ion and laboratory efficiency was improved with the use of the its relation to plasma protein binding. J Nucl Med 11:85-88, 1970 simultaneous method described. The technologist's and 5. Buttfield IH, Wrench JC, Adiseshan N, et al: Intravenous perchlorate in brain scanning: Effects on choroid plexus and lesion the patient's time was utilized more efficiently. The daily visibility. J Nucl Med 14543-545, 1973 schedule of studies was more flexible due to the shorter 6. Maynard CD: Clinical~uclearMedicine. Philadelphia, Lea & total procedure time involved with this method, and the Febiger, 1969, p 163 JOURNAL OF NUCLEAR MEDICINE TECHNOLOGY .