Two-step laser ionization schemes for in-gas laser ionization and spectroscopy of radioactive isotopes.

The in-gas laser ionization and spectroscopy technique has been developed at the Leuven isotope separator on-line facility for the production and in-source laser spectroscopy studies of short-lived radioactive isotopes. In this article, results from a study to identify efficient optical schemes for the two-step resonance laser ionization of 18 elements are presented.

Lymphoscintigraphy and SPECT/CT in multicentric and multifocal breast cancer: does each tumour have a separate drainage pattern? Results of a Dutch multicentre study (MULTISENT).

PURPOSE: To investigate whether lymphoscintigraphy and SPECT/CT after intralesional injection of radiopharmaceutical into each tumour separately in patients with multiple malignancies in one breast yields additional sentinel nodes compared to intralesional injection of the largest tumour only. METHODS: Patients were included prospectively at four centres in The Netherlands. Lymphatic flow was studied using planar lymphoscintigraphy and SPECT/CT until 4 h after administration of (99m)Tc-nanocolloid in the largest tumour. Subsequently, the smaller tumour(s) was injected intratumorally followed by the same imaging sequence. Sentinel nodes were intraoperatively localized using a gamma ray detection probe and vital blue dye. RESULTS: Included in the study were 50 patients. Additional lymphatic drainage was depicted after the second and/or third injection in 32 patients (64%). Comparison of planar images and SPECT/CT images after consecutive injections enabled visualization of the number and location of additional sentinel nodes (32 axillary, 11 internal mammary chain, 2 intramammary, and 1 interpectoral. A sentinel node contained metastases in 17 patients (34%). In five patients with a tumour-positive node in the axilla that was visualized after the first injection, an additional involved axillary node was found after the second injection. In two patients, isolated tumour cells were found in sentinel nodes that were only visualized after the second injection, whilst the sentinel nodes identified after the first injection were tumour-negative. CONCLUSION: Lymphoscintigraphy and SPECT/CT after consecutive intratumoral injections of tracer enable lymphatic mapping of each tumour separately in patients with multiple malignancies within one breast. The high incidence of additional sentinel nodes draining from tumours other than the largest one suggests that separate tumour-related tracer injections may be a more accurate approach to mapping and sampling of sentinel nodes in patients with multicentric or multifocal breast cancer.

New measurement system for on line in core high-energy neutron flux monitoring in materials testing reactor conditions.

Flux monitoring is of great interest for experimental studies in material testing reactors. Nowadays, only the thermal neutron flux can be monitored on line, e.g., using fission chambers or self-powered neutron detectors. In the framework of the Joint Instrumentation Laboratory between SCK-CEN and CEA, we have developed a fast neutron detector system (FNDS) capable of measuring on line the local high-energy neutron flux in fission reactor core and reflector locations. FNDS is based on fission chambers measurements in Campbelling mode. The system consists of two detectors, one detector being mainly sensitive to fast neutrons and the other one to thermal neutrons. On line data processing uses the CEA depletion code DARWIN in order to disentangle fast and thermal neutrons components, taking into account the isotopic evolution of the fissile deposit. The first results of FNDS experimental test in the BR2 reactor are presented in this paper. Several fission chambers have been irradiated up to a fluence of about 7 × 10(20) n∕cm(2). A good agreement (less than 10% discrepancy) was observed between FNDS fast flux estimation and reference flux measurement.

Intraoperative sentinel node identification and sampling in clinically node-negative renal cell carcinoma: initial experience in 20 patients.

PURPOSE: To apply single-photon emission computed tomography (SPECT) in combination with computed tomography (CT) for preoperative identification of sentinel lymph nodes (SNs) and to investigate surgical feasibility and safety of intraoperative sampling. METHODS: A retrospective combined interim analysis of 20 patients from two prospective trials who underwent injection of 99mTc-nanocolloid into the renal tumour for preoperative identification of SN with SPECT/CT and subsequent removal of the tumour and intraoperative sampling using a gamma probe and portable camera. Lymphadenectomy was completed locoregionally. Surgical approach, time, blood loss, intraoperative yield, Clavien complications and anatomical location of SN in correlation with preoperative imaging were evaluated. RESULTS: SPECT/CT detected SN in 14/20 patients (70%), including 4 patients with non-visualisation on planar lymphoscintigraphy. Twenty-six SNs were seen: 17 para-aortic (including interaorto-caval), 4 retrocaval, 1 hilar, 1 celiac trunc, 1 internal mammary and 2 mediastinal and pleural. These latter 4 nodes were not harvested according to protocol. All other SNs, except for 2 weakly radioactive interaorto-caval nodes, were identified and excised with a mean additional time of 20 min. None of the removed SN and locoregional nodes was tumour-bearing. CONCLUSIONS: Intraoperative SN identification and sampling in RCC with preoperative detection on SPECT/CT is surgically safe and feasible. SN from the kidney are mainly localised in the para-aortic region, but aberrant nodes receive direct drainage. Non-visualisation of SN appears in almost a third of the patients. Further studies are required to demonstrate whether accurate mapping of lymphatic drainage and extent of lymphatic spread may have diagnostic and therapeutic implications.

Sentinel node detection in head and neck malignancies: innovations in radioguided surgery.

Sentinel node mapping is becoming a routine procedure for staging of various malignancies, because it can determine lymph node status more precisely. Due to anatomical problems, localizing sentinel nodes in the head and neck region on the basis of conventional images can be difficult. New diagnostic tools can provide better visualization of sentinel nodes. In an attempt to keep up with possible scientific progress, this article reviews new and innovative tools for sentinel node localization in this specific area. The overview comprises a short introduction of the sentinel node procedure as well as indications in the head and neck region. Then the results of SPECT/CT for sentinel node detection are described. Finally, a portable gamma camera to enable intraoperative real-time imaging with improved sentinel node detection is described.

Intraoperative radioguidance with a portable gamma camera: a novel technique for laparoscopic sentinel node localisation in urological malignancies.

PURPOSE: Our aim was to assess the feasibility of intraoperative radioguidance with a portable gamma camera during laparoscopic sentinel node (SN) procedures in urological malignancies. METHODS: We evaluated the use of the intraoperative portable gamma camera in 20 patients: 16 patients with prostate carcinoma (PCC), 2 patients with renal cell carcinoma (RC) and 2 patients with testicular cancer (TC). Intra/peritumoural injection of (99m)Tc-nanocolloid ((99m)Tc) was followed by planar lymphoscintigraphy, SPECT/CT and marking of SN levels. Before laparoscopy a (125)I seed was fixed on the laparoscopic gamma probe as a pointer of SN seeking. The portable gamma camera was set to display the (99m)Tc signal for SN localisation and the (125)I signal for SN seeking. Matching of these signals on screen indicated exact SN localisation, and consequently this SN was removed. RESULTS: The mean injected dose was 218 MBq in PCC, 228 MBq in RC and 88 MBq in TC. Pelvic SN were visualised in all PCC patients, with uncommonly located SN in seven patients. SN metastases were found in seven patients (one in a uncommonly located SN). Both RC patients and TC patients had para-aortic SN, which were all tumour free. A total of 59 SN were removed. The portable gamma camera enabled real-time SN display/identification in 18 patients (90%). CONCLUSION: The use of a portable gamma camera in combination with a laparoscopic gamma probe incorporates intraoperative real-time imaging with improved SN identification in urological malignancies. This procedure might also be useful for SN identification of other deep draining malignancies.

Diagnostic components in harsh radiation environments: possible overlap in R&D requirements of inertial confinement and magnetic fusion systems.

The next generation of large scale fusion devices--ITER/LMJ/NIF--will require diagnostic components to operate in environments far more severe than those encountered in present facilities. This harsh environment is the result of high fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiation, and in some cases, debris and shrapnel, at levels several orders of magnitude higher than those experienced in today's devices. The similarities and dissimilarities between environmental effects on diagnostic components for the inertial confinement and magnetic confinement fusion fields have been assessed. Areas in which considerable overlap have been identified are optical transmission materials and optical fibers in particular, neutron detection systems and electronics needs. Although both fields extensively use cables in the hostile environment, there is little overlap because the environments and requirements are very different.