Rigobert Klett

Routine quality control recommendations for nuclear medicine instrumentation

Keywords Qualitycontrol.Qualityassurance.Nuclearmedicineinstrumentation.Gammacamera.SPECT.PET.CT.Radionuclidecalibrator.Thyroiduptakeprobe.Nonimagingintraoperativeprobe.Gammacountingsystem.Radiationmonitors.PreclinicalPETIntroductionThese recommendations cover routine quality control (QC)of instrumentation used within a nuclear medicine depart-ment. Routine QC testing starts after installation of theinstrument, and after acceptance testing, and continues on aregular basis throughout its lifetime. Additional periodictests may be carried out to provide more in-depth testing.Recommendations for acceptance testing are covered in aseparate document. These recommendations must be con-sideredinthelightofanynationalguidelinesandlegislation,which must be followed. The recommendations cover thetypes of tests to be performed, and suggested frequencies,but they do not specify the protocols to be followed, whichare available from other reference sources quoted.Acceptance and reference testsAfter installation, and before it is put into clinical use, anuclear medicine instrument must undergo thorough andcareful acceptance testing, the aim being to verify that theinstrument performs according to its specifications and itsclinical purpose. Each instrument is supplied with a set ofbasic specifications. These have been produced by themanufacturer according to standard test procedures, whichshould be traceable to standard protocols, such as theNEMA and IEC performance standards [1–4, 11, 17, 30,37]. By following such standard protocols in the clinicalsetting, with support from the vendor for supplyingphantoms and software where necessary, specificationscan be verified and baseline performance data created.Additional tests are usually also needed in order to more

The role of magnetic resonance imaging and scintigraphy in the diagnosis of pathologic changes of the mandible after radiation therapy

A prospective study of 85 patients with oral cancer, treated with high-dose radiation therapy, was performed to assess the value of magnetic resonance imaging (MRI) and scintigraphy for diagnosis of pathologic changes in the mandible. During postradiotherapeutic monitoring, radiation osteomyelitis occurred in 12 cases, tumor recurrences infiltrating the mandible in five cases, and progressive periodontal disease in nine cases. MRI permitted early diagnosis of radiation osteomyelitis in 11 out of 12 cases; only two cases were false positive. In scintigraphy with 99mTc-HDP, all alterations of the mandible, such as osteoradionecrosis, tumor infiltration, and periodontitis, showed a high uptake, resulting in a sensitivity of up to 100%, but a low specificity of 57%. Scintigraphy permitted assessment of the extension and location of the lesions. Both methods were superior to conventional radiography and clinical examination and should be integrated into a comprehensive follow-up program after radiation therapy.

Visualization of segmental irritation points with scintigraphy

SummaryThe aim of this study was the scintigraphic visualization of points of segmental irritation resulting from reversible articular dysfunction. Because of increased cellular metabolism as a result of muscular hypertonus, scintigraphic visualization of these points should be possible with 99mTc-MIBI. This radiopharmaceutical is localized in cells, depending on the metabolism.In 20 patients we compared manual diagnosis with scintigraphy at the thoracic spine in 22 investigations and at the linea nuchae in one investigation. Manual diagnosis was done within 1 h before or after scintigraphy. Analysis of scintigraphy followed manual diagnosis with a minimal interval of 2 weeks.We were able to compare 401 localizations. Manual diagnosis resulted in 39 points of segmental irritation from which 36 points were also shown in scintigraphy. In 44 cases scintigraphic alteration was shown without correlating points in manual diagnosis. In 318 cases both investigations were negative.Therefore, scintigraphic localization of points of segmental irritation was possible. The higher number of scintigraphic alterations should not be interpreted as false-positive results, but as simultaneous visualization of myofascial trigger points or tender points. Because of that it also should be possible to objectize the diagnosis of myofascial trigger points and fibromyalgia.ZusammenfassungZiel der Studie war die szintigraphische Darstellung segmentaler Irritationspunkte in Folge einer reversiblen Gelenkfunktionsstörung. Da bei diesen Irritationspunkten auf Grund des vorliegenden Muskelhypertonus auch ein erhöhter Zellstoffwechsel vorliegt, sollte der Nachweis mit Tc99m-MIBI, einem stoffwechselabhängigen Radiopharmakon möglich sein.Bei 20 Patienten erfolgten 22 vergleichende Untersuchungen der BWS und eine Untersuchung der Linea nuchae. Die Chirodiagnostik erfolgte mit einem maximalen Abstand von 1 Stunde zur Szintigraphie, ohne Kenntnis des Ergebnisses. Die Auswertung der Szintigraphie erfolgte mit einem Mindestabstand von 2 Wochen zur Chirodiagnostik.Es konnten insgesamt 401 Lokalisationen vergleichend ausgewertet werden. 36 der 39 chirodiagnostisch nachgewiesenen Irritationspunkte fanden sich auch szintigraphisch. In 44 Fällen bestand eine szintigraphische Veränderung ohne chirodiagnostisches Korrelat. In 318 Fällen fand sich ein übereinstimmendes negatives Ergebnis.Somit können segmentale Irritationspunkte szintigraphisch nachgewiesen werden. Bei der größeren Zahl an szintigraphischen Veränderungen ist nicht von einem falsch positiven Ergebnis, sondern von der Darstellung anderer muskulärer Triggerpunkte auszugehen. Die Szintigraphie ermöglicht die Objektivierung muskulärer Triggerpunkte unterschiedlicher Ursache, eventuell sogar die Diagnostik der Fibromyalgie.

Diagnosis of focal nodular hyperplasia with hepatobiliary scintigraphy using a modified SPECT technique.

A 29-year-old woman was examined because of malnutrition and recurrent diarrhea. Her serum glutamate oxaloacetate transaminase and serum gamma glutanyl transferase (SGGT) levels were found to be elevated. The patient denied alcohol abuse, blood transfusion, and foreign travel, and she had never used oral contraceptives. Findings of ultrasonography of the liver were normal. A computed tomographic examination suggested focal nodular hyperplasia (FNH), although adenoma could not be excluded. Hepatobiliary imaging was normal and did not manifest the three typical signs of FNH: hypervascularization, increased tumor uptake, and trapping in later images. Repeated scintigraphy using a modified SPECT technique clearly showed FNH.

Radiation synovectomy of the knee joint : Evaluation of bremsstrahlung-detection by using a corpse phantom

AIM Multiple procedures for the quantification of activity leakage in radiation synovectomy of the knee joint have been described in the literature. We compared these procedures considering the real conditions of dispersion and absorption using a corpse phantom. METHODS We simulated different distributions of the activity in the knee joint and a different extra-articular spread into the inguinal lymph nodes. The activity was measured with a gamma-camera. Activity leakage was calculated by measuring the retention in the knee joint only using an anterior view, using the geometric mean of anterior and posterior views, or using the sum of anterior and posterior views. The same procedures were used to quantify the activity leakage by measuring the activity spread into the inguinal lymph nodes. In addition, the influence of scattered rays was evaluated. RESULTS For several procedures we found an excellent association with the real activity leakage, shown by an r(2) between 0.97 and 0.98. When the real value of the leakage is needed, e. g. in dosimetric studies, simultaneously measuring of knee activity and activity in the inguinal lymph nodes in anterior and posterior views and calculation of the geometric mean with exclusion of the scatter rays was found to be the procedure of choice. CONCLUSION When measuring of activity leakage is used for dosimetric calculations, the above-described procedure should be used. When the real value of the leakage is not necessary, e. g. for comparing different therapeutic modalities, several of the procedures can be considered as being equivalent.