Alan J. Britten

Kinetics of hepatic bile acid handling in cholestatic liver disease: Effect of ursodeoxycholic acid

BACKGROUND/AIMS Ursodeoxycholic acid (UDCA) is clinically beneficial in chronic cholestatic liver disease, but the underlying mechanisms are unclear. It has been suggested that intrahepatic retention of endogenous hydrophobic bile acids contributes to cholestasis and that the hydrophilic bile acid UDCA reduces this retention; the aim of our study was to test these hypotheses. METHODS Twelve patients with primary biliary cirrhosis (PBC) and 5 with primary sclerosing cholangitis (PSC) were studied before and during UDCA (10 mg.kg-1.day-1) and compared with 11 healthy controls. Following intravenous 75Se labeled homocholic acid taurine (75SeHCAT) in the fasting state, abdominal gamma camera imaging was performed for 90 minutes. Initial hepatic uptake, transit time, net, and absolute excretory rates for 75SeHCAT were measured. RESULTS Mean initial hepatic uptake was not different between patients and controls (17.2% and 19.9% dose/minute, not significant). However, net and absolute excretory rates were significantly reduced in patients (1.4% vs. 3.7% dose/minute, P < 0.0001; and 2.35% vs. 3.96% dose/minute, P < 0.02, respectively), and hepatic transit time was prolonged (18.7 minutes vs. 11.6 minutes, P < 0.002). UDCA improved net and absolute hepatic excretory rates and transit time (1.43% to 1.96% dose/minute, P < 0.001; 2.35% to 3.15% dose/minute, P < 0.005 and 18.7 to 14.7 minutes, P < 0.001, respectively). However, UDCA did not alter initial hepatic uptake. CONCLUSIONS In PBC and PSC, there is a defect in hepatic bile acid excretion but not in uptake, implying bile acid retention. This retention is reduced by UDCA.

Joint Practice Guidelines for Radionuclide Lymphoscintigraphy for Sentinel Node Localization in Oral/Oropharyngeal Squamous Cell Carcinoma

Involvement of the cervical lymph nodes is the most important prognostic factor for patients with oral/oropharyngeal squamous cell carcinoma (OSCC), and the decision of whether to electively treat patients with clinically negative necks remains a controversial topic. Sentinel node biopsy (SNB) provides a minimally invasive method for determining the disease status of the cervical node basin, without the need for a formal neck dissection. This technique potentially improves the accuracy of histologic nodal staging and avoids overtreating three-quarters of this patient population, minimizing associated morbidity. The technique has been validated for patients with OSCC, and larger-scale studies are in progress to determine its exact role in the management of this patient population. This document is designed to outline the current best practice guidelines for the provision of SNB in patients with early-stage OSCC, and to provide a framework for the currently evolving recommendations for its use. Preparation of this guideline was carried out by a multidisciplinary surgical/nuclear medicine/pathology expert panel under the joint auspices of the European Association of Nuclear Medicine (EANM) Oncology Committee and the Sentinel European Node Trial (SENT) Committee.

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

Joint practice guidelines for radionuclide lymphoscintigraphy for sentinel node localization in oral/oropharyngeal squamous cell carcinoma

Involvement of the cervical lymph nodes is the most important prognostic factor for patients with oral/oropharyngeal squamous cell carcinoma (OSCC), and the decision whether to electively treat patients with clinically negative necks remains a controversial topic. Sentinel node biopsy (SNB) provides a minimally invasive method of determining the disease status of the cervical node basin, without the need for a formal neck dissection. This technique potentially improves the accuracy of histological nodal staging and avoids over-treating three-quarters of this patient population, minimizing associated morbidity. The technique has been validated for patients with OSCC, and larger-scale studies are in progress to determine its exact role in the management of this patient population. This article was designed to outline the current best practice guidelines for the provision of SNB in patients with early-stage OSCC, and to provide a framework for the currently evolving recommendations for its use. These guidelines were prepared by a multidisciplinary surgical/nuclear medicine/pathology expert panel under the joint auspices of the European Association of Nuclear Medicine (EANM) Oncology Committee and the Sentinel European Node Trial Committee.

Acceptance testing for nuclear medicine instrumentation

These recommendations cover acceptance and reference tests that should be performed for acceptance testing of instrumentation used within a nuclear medicine department. These tests must be performed after installation and before the instrument is put into clinical use, and before final payment for the device. These recommendations must be considered in the light of any national guidelines and legislation, which must be followed. The recommendations cover the types of test to be performed, but they do not specify the procedures to be followed, which are available from other reference sources quoted. Acceptance testing is extremely important, as it can affect the whole life performance of a system. The requirement that acceptance testing be performed should be included in the purchase agreement of an instrument. This agreement should specify responsibilities regarding who does acceptance testing, the procedure to be followed when unsatisfactory results are obtained, and who supplies the required phantoms and software. A specific time slot must be allocated for performing acceptance tests.

The growing importance of continuing medical education in nuclear medicine: the role of the European School of Nuclear Medicine

The importance of continuing medical education (CME) in nuclear medicine is increasing because credit hours will be mandatory in the future. In addition to the scientific presentations at the annual congresses, the current knowledge on the most important topics in nuclear medicine should be offered to the nuclear medicine community. In 2000, the “new” European School of Nuclear Medicine (ESNM) was reorganised with the aim of bringing all the educational activities of the EANM under one umbrella. In addition to the “core members” of the ESNM (Lind, Mansi, Pons, Szilvasi; e-mail addresses displayed), the chairpersons of the most important task groups of the EANM are also members of the School. The educational activities of the ESNM can be divided into three categories: 1. Organisation of CME at the annual congress of the EANM 2. Organisation of Central and Eastern European seminars in nuclear medicine 3. Further development of the PET Learning Centre

Moving segments region of interest attenuator for x‐ray fluoroscopy

Region of interest (ROI) imaging has previously been proposed as a means of reducing x-ray fluoroscopy radiation dose. Previous ROI attenuators made of partially attenuating metal plates change beam quality, which may lead to uncertainty in image restoration procedures. The design and construction of a prototype moving segments ROI attenuator (MS-ROI), which maintains beam quality across the whole field of view is described. The x-ray beam intensity is halved by 36 lead segments which are rapidly rotated between the x-ray tube and patient, with a central hole projecting a circular ROI at full intensity. Image processing techniques with automatic detection of the ROI boundary were used to homogenize image brightness across the whole image. Images restored using these techniques were judged to be visually acceptable, with a good match between pixel values inside and outside the ROI. Image contrast within the ROI was improved by 18% due to reduced scatter and veiling glare from the periphery. The introduction of the MS-ROI attenuator also results in a 48% increase in statistical noise in the area outside the ROI, with no significant change in object contrast. The patient entrance dose measured using the dose area product (DAP) method was reduced by 53.4% under manual exposure control, with the dose to operators reduced by 48.4% under automatic brightness control. Further work is needed to determine whether the attenuator can be used with pulsed fluoroscopy, and to reduce vibrational effects on the ROI boundary. The MS-ROI attenuator provides a more constant ratio of central-to-peripheral image intensity, and maintains uniform beam quality and image contrast across the whole image in comparison to simple metal plate attenuators.

Performance assessment of a slat gamma camera collimator for 511 keV imaging

The physical performance of a prototype slat collimator is described for gamma camera planar imaging at 511 keV. Measurements were made of sensitivity, spatial resolution and a septal penetration index at 511 keV. These measurements were repeated with a commercial parallel hole collimator designed for 511 keV imaging. The slat collimator sensitivity was 22.9 times that of the parallel hole collimator with 10 cm tissue equivalent scatter material, and 16.8 times the parallel hole collimator sensitivity in air. Spatial resolution was also better for the slat collimator than the parallel hole collimator (FWHM at 10 cm in air 17.9 mm and 21.2 mm respectively). Septal penetration was compared by a single value for the counts at 120 mm from the point source profile peak, expressed as a percentage of the peak counts, showing less penetration for the slat collimator than the parallel hole collimator (1.9% versus 3.6% respectively). In conclusion, these results show that the slat collimator may have advantages over the parallel hole collimator for 511 keV imaging, though the greater complexity of operation of the slat collimator and potential sources of artefact in slat collimator imaging are recognized.

Repeat planar white cell scanning to monitor short-term therapy of active inflammatory bowel disease : a methodological study and comparison with clinical scores and novel inflammatory markers

Objectives Radiolabelled white cell scans provide non-invasive quantification of inflammatory activity. Clinical activity scores measure severity of disease but are partly subjective. White cell scans may provide a suitable method of monitoring the treatment response of active inflammatory bowel disease. Methods Ten subjects with active ulcerative colitis and 13 subjects with active Crohns disease were recruited. White cell scans were carried out before and 2 weeks after treatment. Prior to each scan, activity scores for ulcerative colitis or Crohns disease were calculated and serum and faecal tumour necrosis factor-&agr; and calprotectin measured. White cell scan activity at 1 h was calculated by using a validated visual grading system. Results Following anti-inflammatory treatment, 70% of white cell scans improved, 17% remained unchanged and 13% deteriorated. In the ulcerative colitis subgroup subjects there was modest agreement for change in scan score and activity scores. In the Crohns disease subjects there was better agreement between change of white cell scan score and clinical scores. Planar white cell scans correlated with the van Hees activity index (r=0.68, P=0.002) and faecal calprotectin (r=0.58, P=0.0003). Changes in planar white cell scans correlated with changes in serum calprotectin (r=0.45, P=0.05). Conclusion Non-invasive white cell scanning is a feasible and objective method to monitor the anti-inflammatory efficacy of treatments for active inflammatory bowel disease.

Highlights of the European Association of Nuclear Medicine Congress, Athens, Greece, 30 September to 4 October 2006

The 2006 EANM Congress, held in Athens, Greece, was once again a major event in the nuclear medicine scientific and educational calendar. The scientific programme, which included the second biennial ISRTRD meeting, confirmed the major developments taking place in (1) the diagnostic and prognostic uses of nuclear medicine imaging (both in PET and in single-photon studies), (2) radionuclide therapies, (3) radiochemistry and radiopharmacy, and (4) physics. This paper outlines the major findings in each of these areas.