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Optical biopsy techniques offer a minimally invasive, real-time alternative to traditional biopsy and pathology during tumor resection surgery. Diffuse reflectance spectroscopy (DRS) is a commonly used technique in optical biopsy. Optical property recovery from spatially resolved DRS data allows quantification of the scattering and absorption properties of tissue. Monte Carlo simulation methods were used to evaluate a unique fiber-optic probe design for a DRS instrument to be used specifically for optical biopsy of the brain. The probe diameter was kept to a minimum to allow usage in small surgical cavities at least 1 cm in diameter. Simulations showed that the close proximity of fibers to the edge of the probe resulted in boundary effects due to reflection of photons from the surrounding air-tissue interface. A new algorithm for rapid optical property recovery was developed that accounts for this reflection and therefore overcomes these effects. The parameters of the algorithm were adjusted for use over the wide range of optical properties encountered in brain tissue, and its precision was evaluated by subjecting it to random noise. This algorithm can be adapted to work with any probe geometry to allow optical property recovery in small surgical cavities.

Importance 177 Lu therapy as part of theranostic treatment for cancer is expanding but it can be a challenge for sites with limited radiation protection staff to implement the radiation safety program required for therapeutic nuclear medicine. Objective To increase the adoption of 177 Lu therapy, especially in smaller centers and clinics, by providing a collection of radiation safety best practices and operational experience. To provide a resource for radiation safety officers supporting the implementation of a 177 Lu therapy program. Methods A panel of 11 radiation safety professionals representing sites across Canada and the United States with experience delivering 177 Lu therapy was assembled and discussed their responses to a list of questions focused on the following radiation safety topics: facility layout and design; radiation safety program; and drug management and patient care. Results A comprehensive set of best practice guidelines for clinical radiation safety during 177 Lu therapy has been developed based on the collective operational experience of a group of radiation safety professionals. Significant findings included that 177 Lu therapy is often safely administered in unshielded rooms, that staff radiation exposure associated with 177 Lu therapy is minimal relative to other nuclear medicine programs, and that some relatively simple preparation in advance including papering of common surfaces and planning for incontinence can effectively control contamination during therapy. Conclusion The guidance contained in this paper will assist radiation safety professionals in the implementation of safe, effective 177 Lu therapy programs, even at smaller sites with limited to no experience in therapeutic nuclear medicine.

Optical spectroscopy of human tissue has been widely applied within the field of biomedical optics to allow rapid, in vivo characterization and analysis of the tissue. When designing an instrument of this type, an imaging spectrometer is often employed to allow for simultaneous analysis of distinct signals. This is especially important when performing spatially resolved diffuse reflectance spectroscopy. In this article, an algorithm is presented that allows for the automated processing of 2-dimensional images acquired from an imaging spectrometer. The algorithm automatically defines distinct spectrometer tracks and adaptively compensates for distortion introduced by optical components in the imaging chain. Crosstalk resulting from the overlap of adjacent spectrometer tracks in the image is detected and subtracted from each signal. The algorithm's performance is demonstrated in the processing of spatially resolved diffuse reflectance spectra recovered from an Intralipid and ink liquid phantom and is shown to increase the range of wavelengths over which usable data can be recovered.

An optical system using diffuse reflectance spectroscopy (DRS) and time‐resolved laser induced fluorescence spectroscopy (TR‐LIFS) is being developed to identify surgical margins during brain tumour resection. Since initial trials will be performed ex vivo on small samples, we investigated our ability to perform DRS for these small sample volumes. We examined both the effects of decreasing sample volume on the DRS signal and decreasing probe size on our ability to recover optical properties. Sample volume effects were studied by performing DRS measurements on bovine brain tissue samples of various sizes and comparing the signals to those for very large samples. A decrease in DRS signal strength was observed at sample volumes of less than 500 mm3. Probe size effects were studied using Monte Carlo simulations to obtain the spatially‐resolved reflectance using the optical properties of human brain tissue. Varying amounts of noise were added to the reflectance, and optical properties were recovered by fitting to Monte Carlo generated reflectance curves. The recovered properties were compared to their actual values as the maximum radius used for fitting was reduced. Our ability to recover the absorption coefficient was improved when fitting to absolute reflectance data.