Is there a role for a handheld gamma camera (TReCam) in the SNOLL breast cancer procedure?

BACKGROUND: Sentinel node and occult lesion localization (SNOLL) calls for a combination of two specific procedures: intraoperative detection of sentinel lymph node (SLN) and radio-guided occult lesion localization (ROLL). The safety and benefits of radio-guided localization in the surgical treatment of non-palpable breast cancer have been confirmed. The aim of this study was to evaluate the potential role for an intra-operative handheld tumor resection gamma camera (TReCam) in SNOLL procedures. METHODS: Fifteen patients were enrolled. The SNOLL procedure was performed in all patients with conventional lymphoscintigraphy (LS). TReCam was used to obtain nuclear imaging in the operating theater. Concordance between LS and TReCam images, duration of use and assessment of difficulties in data acquisition with TReCam were reported. RESULTS: Concordance for tumor localization between single-detector gamma probe and TReCam was excellent (15/15). The number of radioactive SLNs visualized between LS and TReCam was equivalent in 53.3% of cases (8/15). TReCam was considered to be very easy-to-use (12/15) or easy-to-use (3/15). Average duration of acquisition with TReCam was 4 minutes and 45 seconds for the SLN procedure, and 2 minutes and 10 seconds for lumpectomy. CONCLUSIONS: This study suggests that TReCam is easy-to-use and does not increase operative time. Its exact role in radio-guided surgery needs to be clearly defined in a larger study. However, its usefulness and benefits in radio-guided breast surgery seem to be promising.

Optical phantoms with variable properties and geometries for diffuse and fluorescence optical spectroscopy.

Growing interest in optical instruments for biomedical applications has increased the use of optically calibrated phantoms. Often associated with tissue modeling, phantoms allow the characterization of optical devices for clinical purposes. Fluorescent gel phantoms have been developed, mimicking optical properties of healthy and tumorous brain tissues. Specific geometries of dedicated molds offer multiple-layer phantoms with variable thicknesses and monolayer phantoms with cylindrical inclusions at various depths and diameters. Organic chromophores are added to allow fluorescence spectroscopy. These phantoms are designed to be used with 405 nm as the excitation wavelength. This wavelength is then adapted to excite large endogenous molecules. The benefits of these phantoms in understanding fluorescence tissue analysis are then demonstrated. In particular, detectability aspects as a function of geometrical and optical parameters are presented and discussed.

The usefulness of a preoperative compact imager, a hand-held gamma-camera for breast cancer sentinel node biopsy: final results of a prospective double-blind, clinical study.

UNLABELLED: The aim of this study was to compare the effectiveness of a hand-held preoperative compact imager (POCI) camera with conventional lymphoscintigraphy using a γ-camera for sentinel lymph node (SLN) detection in breast cancer. METHODS: The main objective was to demonstrate the noninferiority of the POCI relative to conventional lymphoscintigraphy and to compare the number of SLNs detected by the 2 imaging devices. Our study, a clinical prospective, double-blind, noninferiority study, planned to include 200 patients with early breast cancer and started in January 2006. A standard SLN protocol (4 periareolar injections of 37 MBq of (99m)Tc-nanocolloids, 2 h before lymphoscintigraphy) was performed preoperatively using a conventional γ-camera and then the POCI camera. Scans were obtained by 2 different nuclear medicine physicians unaware of each other's results. The day after, in the operating room, the surgeon, after receiving the previous results, used the counting probe for surgical SLN biopsy. The number and localization of axillary SLNs obtained by lymphoscintigraphy and the POCI and the duration of the whole procedure were determined. RESULTS: Among the 162 patients included, 138 were evaluable. The POCI detected more SLNs than did lymphoscintigraphy in 50 patients (36%), the same number of in 54 patients (39%), and fewer SLNs in 34 patients (25%), representing 84 (61%) discordant pairs. The noninferiority of preoperative compact imaging of axillary SLNs numbers was found to be statistically significant (95% confidence interval, 30%-52%, P = 0.025) using the McNemar test. The duration of acquisition was shorter using the POCI (<10 min in 84% [n = 117] of patients; mean, 7.5 ± 3.3 min) than lymphoscintigraphy (13% [n = 18] of patients; mean, 15.7 ± 3.4 min), with P < 0.001 using the McNemar test for paired proportions. CONCLUSION: Preoperative compact imaging using a hand-held camera was able to predict the number and localization of breast cancer SLNs and was not inferior to conventional lymphoscintigraphy in this study. Further studies will determine whether preoperative compact imaging could replace lymphoscintigraphy, especially in surgical centers without an on-site nuclear medicine department.

Improved sample injection and illumination for multicapillary systems.

Multicapillary electrophoresis continues to see improvements in speed, robustness, and reliability. This paper reports on our work on two components belonging to a multicapillary sequencer developed in our group. Injection of the DNA samples into the capillaries was optimized to make it reproducible and to reduce the amount of sample volume required. An alternative laser illumination of the capillaries was also developed. Light intensity in the capillaries was increased as a result of a step-by-step scanning of the laser and the use of microlenses in front of the capillaries.

[Place of hand-held gamma camera (POCI) in sentinel node biopsy]. / Apport d'un radio-imageur portable (POCI) dans la procédure du ganglion sentinelle.

The main interest in the sentinel node (SN) detection concept has led to the development of several prototypes of hand held gamma cameras. After the first successful clinical trials with intra-operative imaging probes, the time has come to evaluate the potential benefits of these devices. The objective of this review was to show the potential interest of a hand-held camera POCI to perform a lymphoscintigraphy in order to precisely localize SNs in patients with breast cancer.

A hand-held imaging probe for radio-guided surgery: physical performance and preliminary clinical experience.

Improvements in the specificity of radiopharmaceutical compounds have been paralleled by an upsurge of interest in developing small detectors to assist surgeons in localizing tumour tissue during surgery. This study reports the main technical features and physical characteristics of a new hand-held gamma camera dedicated to accurate and real-time intra-operative imaging. First clinical experience is also reported. The POCI (Per-operative Compact Imager) camera consists of a head module composed of a high-resolution interchangeable lead collimator and a CsI(Na) crystal plate optically coupled to an intensified position-sensitive diode. The current prototype has a 40-mm diameter field of view, an outer diameter of 9.5 cm, a length of 9 cm and a weight of 1.2 kg. Overall detector imaging characteristics were evaluated by technetium-99m phantom measurements. Three patients with breast cancer previously scheduled to undergo sentinel lymph node detection were selected for the preliminary clinical experience. Preoperative images of the lymphatic basin obtained using the POCI camera were compared with conventional transcutaneous explorations using a non-imaging gamma probe. The full-width at half-maximum (FWHM) spatial resolution was investigated in both air and scattering medium; when the phantom was placed in contact with the collimator, the POCI camera exhibited a 3.2 mm FWHM. The corresponding sensitivity was 290 cps/MBq. The preliminary clinical results showed that POCI was able to predict the number and location of all SLNs. In one case, two deep radioactive nodes missed by the gamma probe were detected on the intra-operative images. This very initial experience demonstrates that the physical performance of the POCI camera is adequate for radio-guided surgery. These results are sufficiently encouraging to prompt further evaluation studies designed to determine the specific and optimal clinical role of intra-operative imaging devices.