Gamma Probe Research Articles

Reliability and outcomes of lymph nodes biopsy in cT1-cT2 N0 supraglottic laryngeal squamous cell carcinoma.

In oral and oropharyngeal squamous cell carcinoma (SCC), sentinel node biopsy (SNB) was described as a reliable and reproductive alternative to elective neck dissection for the staging of clinical N0 T1-T2 patients. The SNB technique in supraglottic laryngeal SCC was successfully described in small series. The aim of this study is to analyze retrospectively the results of SNB technique in supraglottic SCC in CHU Godinne, to determine if the technique is reliable and may be proposed in a future multicentral prospective trial. The study involved a retrospective analysis of 39 patients who underwent surgery between 2003 and 2019 at CHU Godinne. All patients presented with clinical N0 neck status. The SNB procedure included general anesthesia, 99-technetium colloid peritumoral injection, and lymphoscintigraphy. The hand-held gamma probe was utilized for SNB after tumoral resection during the same operating session. Out of 39 patients, 36 underwent SNB as the sole staging tool, while 3 patients received SNB in combination with elective neck dissection. Primary outcome was the 2-years neck recurrence-free survival (RFS). Secondary outcomes were the 2- and 5-years disease-specific survival (DSS). Additionally, sensitivity and negative predictive value (NPV) of the SNB technique were analyzed. Sentinel nodes were successfully identified in all 39 patients. An average of 4 nodes excised per patient. Positives SN were detected in 23% (9 in 39) cases, leading to subsequent selective neck dissection. Two cases of neck recurrence were observed, both considered as false negatives, occurring after an average of 3.5 months. Th median follow-up period was 48 months with a 2-year RFS of 95%. Sensitivity and NPV of the SNB technique were found to be 82% and 94%, respectively. Two and five years DSS were 84% and 71.7%, respectively. The results suggest that SNB in T1-T2 supraglottic SCC is a feasible and reliable technique for managing the neck in N0 early-stage patients. However, to establish its oncological equivalence with selective node dissection, further prospective and comparative studies are warranted. The findings of this study underscore the importance of ongoing research in refining and validating the role of SNB in the management of supraglottic SCC, potentially paving the way for more widespread adoption in clinical practice.

The Sentinel Node and Occult Lesion Localization (SNOLL) Technique Using a Single Radiopharmaceutical in Non-palpable Breast Lesions.

In order to perform a full surgical resection on non-palpable breast lesions, a current method necessitates correct intraoperative localization. Additionally, because it is an important prognostic factor for these patients, the examination of the lymph node status is crucial. The aim of this study was to evaluate the efficiency of the sentinel node and occult lesion localization (SNOLL) technique in localizing nonpalpable breast lesions together with sentinel lymph node (SLN) using a single radiotracer, that is, nanocolloid particles of human serum albumin (NC) labeled with technetium-99m (99mTc). 39 patients were included, each having a single non-palpable breast lesion and clinically no evidence of axillary disease. Patients received 99mTc- NC intratumorally on the same day as surgery under the guidance of ultrasound. Planar and single-photon emission computed tomography/computed tomography lymphoscintigraphy were performed to localize the breast lesion and the SLN. The occult breast lesion and SLN were both localized using a hand-held gamma-probe, which was also utilized to determine the optimal access pathway for surgery. In order to ensure a radical treatment in a single surgical session and reduce the amount of normal tissue that would need to be removed, the surgical field was checked with the gamma probe after the specimen was removed to confirm the lack of residual sources of considerable radioactivity. Breast lesions were successfully localized and removed in all patients. Pathological findings revealed breast carcinoma in 11/39 patients (28%) and benign lesions in 28 (72%). Axillary SLNs were detected in 31/39 (79.5%) patients. The metastatic involvement of SLN was only seen in two cases. While the identification rate of the SNOLL technique performed with an intratumoral injection of 99mTc-NC as the sole radiotracer in non-palpable breast lesions was great, it was not fully satisfactory in SLNs.

SENTINEL LYMPH NODE BIOPSY IN THE MANAGEMENT OF PATIENTS WITH MALIGNANT MELANOMA

Objectives: To evaluate the efficacy of sentinel lymph node biopsy in the treatment of malignant melanoma. Materials and Methods: Thirty-two melanoma patients without distant or clinical lymph node metastasis underwent preoperative lymphoscintigraphy using Tc99m and a handheld gamma probe to identify sentinel lymph nodes for biopsy. In cases with detected sentinel lymph node metastasis, the patient may require total complete lymph node dissection, combined with optional systemic therapy. Follow-up was performed to evaluate the efficacy of this procedure. Results: In 32 melanoma patients, the most common site of primary tumors was the extremity, accounting for 90.6%, with a mean Breslow index (thickness of the primary tumor) of 1.84 mm. The incidence of microscopic lymph node metastasis was 34.4%. For cases with no detected sentinel lymph node metastasis, 100% of patients had a stable condition, and no recurrence or metastasis was detected. In 11 cases with occult nodal metastasis: 2 deaths, 4 patients were treated with chemotherapy, and 5 cases without chemotherapy. The mean duration of hospitalization for the group with sentinel lymph node metastasis was greater than that of the group without sentinel lymph node metastasis, 25.1 ± 3.1 days and 13.5 ± 1.3 days, respectively. Conclusion: Our results suggest that sentinel lymph node biopsy is a less invasive technique for melanoma patients with no clinically detectable lymph node and distant metastases. This procedure has shown initial outcomes, but it is necessary to conduct a study with a larger sample size and a longer follow-up time, as well as comparing it with a control group for accurate evaluation. Received 23 June 2023Revised 22 September 2023Accepted 27 November 2023

Steerable DROP-IN radioguidance during minimal-invasive non-robotic cervical and endometrial sentinel lymph node surgery

PurposeThe recently introduced tethered DROP-IN gamma probe has revolutionized the way robotic radioguided surgery is performed, fully exploiting the nature of steerable robotic instruments. Given this success, the current first-in-human study investigates if the DROP-IN can also provide benefit in combination with steerable non-robotic instruments during conventional laparoscopic surgery, showing equivalence or even benefit over a traditional rigid gamma probe.MethodsThe evaluation was performed in ten patients during laparoscopic cervical (n = 4) and endometrial (n = 6) cancer sentinel lymph node (SLN) procedures. Surgical guidance was provided using the hybrid, or bi-modal, SLN tracer ICG-99mTc-nanocolloid. SLN detection was compared between the traditional rigid laparoscopic gamma probe, the combination of a DROP-IN gamma probe and a steerable laparoscopic instrument (LaproFlex), and fluorescence imaging.ResultsThe gynecologists experienced an enlarged freedom of movement when using the DROP-IN + LaproFlex combination compared to the rigid laparoscopic probe, making it possible to better isolate the SLN signal from background signals. This did not translate into a change in the SLN find rate yet. In both cervical and endometrial cancer combined, the rigid probe and DROP-IN + LaproFlex combination provided an equivalent detection rate of 96%, while fluorescence provided 85%.ConclusionWe have successfully demonstrated the in-human use of steerable DROP-IN radioguidance during laparoscopic cervical and endometrial cancer SLN procedures, expanding the utility beyond robotic procedures. Indicating an improved surgical experience, these findings encourage further investigation and consideration on a path towards routine clinical practice and improved patient outcome.Trial registrationHCB/2021/0777 and NCT04492995; https://clinicaltrials.gov/study/NCT04492995

Exploring the role of combined external beam radiotherapy and targeted radioligand therapy with [177Lu]Lu-PSMA-617 for prostate cancer - from bench to bedside.

Management of prostate cancer (PC) might be improved by combining external beam radiotherapy (EBRT) and prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) with lutetium-177 (177Lu)-labeled PSMA inhibitors. We hypothesized a higher efficacy of the combination due to augmentation of the radiation dose to the tumor and interactions of EBRT with PSMA expression potentially increasing radiopharmaceutical uptake. Therefore, this study analyzed the influence of radiation on PSMA expression levels in vitro. The results were translated to evaluate the efficacy of the combination of photon EBRT and [177Lu]Lu-PSMA-617 in a murine PC xenograft model. Finally, a clinical case report on a combined elective field EBRT with RLT dose escalation illustrates a proof-of-concept. Methods: PSMA gene and protein expression were assessed in human PSMA-overexpressing LNCaP cells after irradiation using reverse transcription quantitative polymerase chain reaction (RT-qPCR), flow cytometry and On-Cell Western assays. In the in vivo therapy study, LNCaP tumor-bearing BALB/c nu/nu mice were irradiated once with 2 Gy X-ray EBRT and injected with 40 MBq [177Lu]Lu-PSMA-617 after 4 h or received single or no treatment (n = 10 each). Tumor-absorbed doses by [177Lu]Lu-PSMA-617 were calculated according to the Medical Internal Radiation Dosimetry (MIRD) formalism after deriving time-activity curves using a gamma probe. An exemplified patient case is demonstrated where fractionated EBRT (54 Gy to prostate; 45 Gy to pelvic lymphatics) and three cycles of [177Lu]Lu-PSMA-617 (3.4-6.0 GBq per cycle) were sequentially combined under concurrent androgen deprivation for treating locally advanced PC. Results: At 4 h following irradiation with 2-8 Gy, LNCaP cells displayed a PSMA protein upregulation by around 18% relative to non-irradiated cells, and a stronger upregulation on mRNA level (up to 2.6-fold). This effect was reversed by 24 h when PSMA protein levels were downregulated by up to 22%. Mice treated with the combination therapy showed significantly improved outcomes regarding tumor control and median survival (p < 0.0001) as compared to single or no treatment. Relative to monotherapy with PSMA-RLT or EBRT, the tumor doubling time was prolonged 1.7- or 2.7-fold and the median survival was extended by 24% or 60% with the combination, respectively. Additionally, tumors treated with EBRT exhibited a 14% higher uptake of the radiopharmaceutical as evident from the calculated tumor-absorbed dose, albeit with high variability in the data. Concerning the patient case, the tri-modality treatment was well tolerated and the patient responded with a long-lasting complete biochemical remission for five years following end of PSMA-RLT. The patient then developed a biochemical relapse with oligo-recurrent disease on follow-up imaging. Conclusion: The present preclinical and clinical data demonstrate that the combination of EBRT with dose escalation by PSMA-RLT improves tumor control and potentially prolongs survival. This may pave the way for further clinical investigations of this approach to explore the curative potential of the combination therapy.

Perovskite-based detector for reactor dosimetry monitoring

Hybrid halide perovskites have demonstrated significant efficiency in detecting a broad spectrum of high-energy radiation, including X-rays, gamma rays (γ-rays), and neutrons. Given the common occurrence of mixed radiation fields, we investigated the performance of a perovskite-based detector in a neutron-gamma mixed field. A large methylammonium lead tribromide (MAPbBr3) single crystal (SC) was synthesized via the oriented crystal-crystal intergrowth method. This SC was used to fabricate a gamma detector with carbon electrodes, which was tested in the CROCUS zero-power reactor cavity. The detector’s photocurrent response exhibited a strong correlation with known gamma dose rates, as measured by an ambient Berthold LB 112 gamma probe, facilitating the accurate conversion of photocurrent to dose rate. Notably, the device did not exhibit degradation under neutron radiation exposure. To further assess the impact of neutrons, X-ray diffraction and electron paramagnetic resonance analyses were performed on small MAPbBr3 SCs grown by inverse temperature crystallization. These SCs were irradiated within the CROCUS reactor core and by a Pu-Be neutron source at liquid nitrogen temperature. Our findings indicate that the perovskite material can withstand the nominal in-core operation conditions of the CROCUS reactor. Additionally, it endures irradiation at liquid nitrogen temperature, corresponding to a fast neutron fluence of approximately 1010 cm-2 and a gamma radiation dose of about 50 Gy, confirming only the temporary creation of defects. No signs of long-term deterioration were observed, suggesting a potential self-healing mechanism. This resilience positions perovskite SCs as viable candidates for in-core radiation detection, supporting the further development of miniaturized MAPbBr3 SC devices for such applications.

Indocyanine green fluorescence imaging: an effective method to find inguinal sentinel lymph node in a case of vulvar carcinoma.

The aim was to demonstrate that the technique of near infrared range/indocyanine green (NIR/ICG) could aid the detection of inguinal sentinel lymph nodes in patients with vulvar cancer, in addition to technetium-99m (Tc-99m) scanning. We present a case report of sentinel lymph node detection in a patient with vulvar cancer with two methods: Tc-99m scan and NIR/ICG. The video showed that bilateral inguinal lymph nodes were detected both by Tc gamma probe and NIR/ICG. NIR/ICG may be a safe and effective alternative method for identifying sentinel lymph nodes in cases of early-stage vulvar cancer, although more evidence is required.

Predictors of Bilateral SLN Radiocolloid Detection in Endometrial Carcinoma.

Introduction Sentinel lymph node (SLN) mapping is an alternative method to conventional lymphadenectomy for nodal status assessment in patients with stage I/II endometrial carcinoma (EC). This study aimed to analyze the potential predictors of unsuccessful bilateral detection of SLN after the application of radiocolloid in EC. Materials and Methods A prospective, observational, cross-sectional study was performed on 41 patients with EC in preoperative stage I, who underwent SLN mapping after cervical application of 4mCi 99m Tc-SENTI-SCINT. The demographic, clinical, and tumor-related data were obtained from the patient's medical records. Univariate analysis was used to analyze the potential factors associated with an unsuccessful bilateral SLN biopsy. Results The bilateral SLN detection rate of planar lymphoscintigraphy, single photon emission computed tomography/computed tomography, and gamma probe was 29.26, 41.46, and 26.82%, correspondingly. None of the 16 analyzed risk factors showed statistical significance for nonconclusive bilateral SLN biopsy. Conclusion Larger scale studies are needed to determine the exact risk factors for unsuccessful bilateral mapping of the lymphatic drainage after cervical application of the radiotracers. This will eventually lead to improvement in bilateral SLN detection in EC patients, so unilateral lymphadenectomy could be avoided.

Setting-up a training programme for intraoperative molecular imaging and sentinel node mapping: how to teach? How to learn?

The current expansion of image-guided surgery is closely related to the role played by radio-guided surgery in supporting the sentinel node (SN) procedure during more than three decades. The so-called triple approach (lymphoscintigraphy, gamma probe detection and blue dye) was not only essential in the seminal validation of the SN procedure but also a first collective learning effort based on skill transfer and outcome-related evaluation which laid the fundaments to delineate the field of intraoperative molecular imaging (IMI) based on a similar multimodality approach and multidisciplinary practice. These elements are also becoming valid in the current incorporation of SPECT/CT and PET/CT to existing and new protocols of IMI procedures and SN mapping concerning other clinical applications. On the other hand, there is a growing tendency to combine novel modern technologies in an allied role with gamma guidance in the operating room following the development of hybrid tracers and multimodal detection approaches. Against this background, learning initiatives are required for professionals working in this area. This objective has led to a group of European practitioners with large experience in SN mapping and IMI applications to give shape to a programme made up out of specific learning modules aimed to be used as a conductive thread in peripherical or centralised training instances concerning the topic. The presented work, written as a tutorial review, is placed in an available prior-art context and is primarily aimed at medical and paramedical practitioners as well as at hardware and software developers.

Machine learning algorithm for localization of nuclear materials based on gamma probe data to verify the denuclearization

Machine learning algorithm for localization of nuclear materials based on gamma probe data to verify the denuclearization

Innovación continuada en cirugía radioguiada de precisión

Since its origins, nuclear medicine has faced technological changes that led to modifying operating modes and adapting protocols. In the field of radioguided surgery, the incorporation of preoperative scintigraphic imaging and intraoperative detection with the gamma probe provided a definitive boost to sentinel lymph node biopsy to become a standard procedure for melanoma and breast cancer.The various technological innovations and consequent adaptation of protocols come together in the coexistence of the disruptive and the gradual. As obvious examples we have the introduction of SPECT/CT in the preoperative field and Drop-in probes in the intraoperative field. Other innovative aspects with possible application in radio-guided surgery are based on the application of artificial intelligence, navigation and telecare.

Radio-Guided Occult Lesion Localization With 99m Tc for the Localization of Nonpalpable Melanoma and Soft Tissue Sarcoma Lesions: A Feasibility Study.

Localization techniques are needed to facilitate resection of nonpalpable lesions. In this study, the feasibility of radio-guided occult lesion localization (ROLL) with 99m Tc is investigated for the localization of nonpalpable, small, suspicious, or proven melanoma or soft tissue sarcoma lesions at various locations throughout the body. Patients with nonpalpable, suspicious, or proven melanoma or soft tissue sarcoma lesions were selected for this study. Within 24 hours before surgery, a median dose of 33.92 MBq 99m Tc-labeled human albumin particles ( 99m Tc-NA or 99m Tc-MAA) was injected in the lesion under ultrasound guidance. A hand-held gamma probe was used to detect the radioactive signal and guidance during surgery. In this study, 20 patients with a total of 25 lesions were included and analyzed. The median size of the lesions was 1.8 cm (interquartile range [IQR], 1.8-4.0 cm), of which 44% were intramuscular located and 36% were subcutaneous, and 20% consisted of suspicious lymph nodes, mostly in the lower extremity. At median 4 hours (IQR, 3-6 hours) postinjection, 99m Tc ROLL showed a 100% intraoperative identification rate with proper signal identification with the gamma probe in all patients. With a median surgery time of 76 minutes (IQR, 45-157 minutes), all targeted lesions could be resected without 99m Tc-related complications, resulting in 88% microscopically margin-negative resection. No reoperations were needed for the same lesion. The 99m Tc ROLL procedure is feasible for the localization and excision of small, nonpalpable melanoma and soft tissue sarcoma lesions at various locations in the body.

Continuous innovation in precision radio-guided surgery

Since its origins, nuclear medicine has faced technological changes that led to modifying operating modes and adapting protocols. In the field of radioguided surgery, the incorporation of preoperative scintigraphic imaging and intraoperative detection with the gamma probe provided a definitive boost to sentinel lymph node biopsy to become a standard procedure for melanoma and breast cancer.The various technological innovations and consequent adaptation of protocols come together in the coexistence of the disruptive and the gradual. As obvious examples we have the introduction of SPECT/CT in the preoperative field and Drop-in probes in the intraoperative field. Other innovative aspects with possible application in radio-guided surgery are based on the application of artificial intelligence, navigation and telecare.

Sentinel lymph node biopsy for head and neck malignancies utilizing simultaneous radioisotope gamma probe and indocyanine green fluorescence navigation.

We depict an innovative surgical approach for sentinel lymph node biopsy (SLNB) in head and neck malignancies that utilizes both near-infrared (NIR) imaging with indocyanine green (ICG) dye and hand-held gamma probe intraoperatively to isolate and excise SLNs. Twenty-one patients presented to our institution with cutaneous melanoma, cutaneous squamous cell carcinoma (SCC), and oral cavity SCC tumors that met criteria for SLNB based on tumor depth and histology. The video offers a step-by-step approach for this technique along with descriptions of recommended equipment. Among 21 patients, two patients had positive SLNs on final pathology. One patient developed a local recurrence over an average of 16.2 months of follow-up (SD = 15.6). SLNB with ICG and radionucleotide co-localization may enhance the identification of sentinel nodes without compromising outcomes in the hands of surgeons well-versed in the technique.

Evaluation of the efficacy of using indocyanine green associated with fluorescence in sentinel lymph node biopsy.

Sentinel lymph node biopsy is the technique recommended for the axillary staging of patients with breast cancer in the initial stages without clinical axillary involvement. Three techniques are widely used globally to detect sentinel lymph nodes: patent blue, the radiopharmaceutical technetium 99 with gamma probe, and the combination of these two. To evaluate the sentinel lymph node detection rate with an innovative technique: indocyanine green (ICG) associated with fluorescence in breast cancer patients, and compare it with patent blue and a combination of patent blue and indocyanine green. 99 patients were sequentially (not randomly) allocated into 3 arms with 33 patients submitted to sentinel lymph node techniques. One arm underwent patent blue dying, the other indocyanine green, and the third received a combination of both. The detection rates between arms were compared. The detection rate in identifying the sentinel lymph node was 78.8% with patent blue, 93.9% with indocyanine green, and 100% with the combination. Indocyanine green identified two sentinel nodes in 48.5% of patients; the other groups more commonly had only one node identified. The mean time to sentinel lymph node identification was 20.6 ± 10.7 SD (standard deviation) minutes among patients submitted to the patent blue dye, 8.6 ± 6.6 minutes in the indocyanine green arm, and 10 ± 8.9 minutes in the combined group (P<0.001; Student's test). The mean surgery time was 69.4 ± 16.9; 55.1 ± 13.9; and 69.4 ± 19.3 minutes respectively (P<0.001; Student's test). The sentinel lymph node detection rate by fluorescence using indocyanine green was 93.9%, considered adequate. The rates using patent blue, indocyanine green, and patent blue plus indocyanine green (combined) were significantly different, and the indocyanine green alone is also acceptable, since it has a good performance in sentinel lymph node identification and it can avoid tattooing, with a 100% sentinel lymph node detection rate when combined with patent blue.

Sentinel lymph node mapping: current applications and future perspectives in thyroid carcinoma.

Sentinel lymph node (SLN) mapping is a standard, minimally-invasive diagnostic method in the surgical treatment of many solid tumors, as for example melanoma and breast cancer, for detecting the presence of regional nodal metastases. A negative SLN accurately indicates the absence of metastases in the other regional lymph nodes (LN), thus avoiding unnecessary lymph nodal dissection. Papillary thyroid carcinoma (PTC) is the most common type of thyroid carcinoma (TC) with cervical LN metastases at diagnosis in 20-90%, and nodal involvement correlates with local persistence/recurrence. The SLN in PTC is an intraoperative method for staging preoperative N0 patients and for detecting metastatic LNs "in and outside" the cervical LN central compartment; it represents an alternative method to prophylactic central neck node dissection. In this review we summarize different methods and results of the use of SLN in TC. The SLN identification techniques currently used include the selective vital-dye (VD) method, 99mTc-nanocolloid planar lymphoscintigraphy with intraoperative use of a hand-held gamma probe (LS), the combination LS + VD, and the combination LS and preoperative SPECT-CT (LS + SPECT/CT). The application of the SLN procedure in TC has been described in many studies, however, the techniques are heterogeneous, and the role of SLN in TC, with indications, results, advantages and limits, is still debated.

Radioguided Occult Lesion Localization Technique for Biopsy of Nonpalpable Subcutaneous Lesions in Suspected Metastatic Melanoma.

In patients with a history of melanoma, the risk of recurrence depends on the stage at diagnosis. Patients who present with more advanced disease are more likely to experience recurrence; patients with less advanced disease at presentation have slower progression and lower likelihood of recurrence. The aim of this study was to evaluate the use of a minimally invasive and targeted technique as a diagnostic and therapeutic tool for the excision of nonpalpable lesions suspected to be melanoma metastases. The authors evaluated 21 patients with stage IIB, IIC, or III melanoma and subcutaneous nonpalpable lesions with a high risk of malignancy on positron emission tomography/computed tomography scan during oncologic follow-up. To guide biopsy, the authors used the radioguided occult lesion localization technique, using intralesional injection of technetium-99m albumin macroaggregates the day before surgery. During surgery, a handheld gamma probe was used to locate the lesions. Surgical localization of radiolabeled lesions was achieved in all cases. Relapsed melanoma was histologically confirmed in 13 patients. This technique proved to be a simple, safe, and effective method to detect and biopsy nonpalpable or difficult-to-locate lesions in suspected metastatic melanoma. The main advantage was disease restaging (eg, from stage II to III), allowing patients to access adjuvant therapies not approved as early-stage melanoma treatment. Therapeutic, IV.

Determination of Lesion Localization with Intraoperative Gamma Probe in the Presence of a Primary Parathyroid Lesion with Early Wash-Out in Radionuclide

Objective: In this research, we aimed to evaluate the success of the minimally invasive surgical method performed with intraoperative gamma-probe despite early wash-out in solitary primary parathyroid lesions and to contribute to the literature on this subject. Methods: This retrospective study included 48 adult patients diagnosed with hyperparathyroidism, with an average parathormone value of 105 pg/mL (range: 82-127 pg/mL). Radionuclide imaging was conducted using Tc-99m sestamibi and Tc-99m-pertechnetate. Minimally invasive surgery with an intraoperative gamma probe was planned for patients with primary parathyroid lesions and surgical indications. At the conclusion of the operation, count equalization was observed in all four quadrants. Results: Minimally invasive surgery was performed on 42 patients with the assistance of an intraoperative gamma probe. In 6 patients, the procedure was extended to conduct a four-gland exploration due to early wash-out. Each patient had one pathological lesion removed, all of which were histopathologically confirmed as parathyroid adenomas. Among the 6 patients with extended surgeries, 4 experienced early wash-out, and all 6 had been diagnosed with multinodular goiter. Conclusion: In cases with primary hyperparathyroidism, it is aimed to remove the pathological lesion with minimally invasive surgery and leave the glands that continue their normal function in place. Preoperative localization methods help the surgeon in this regard, but pathologies in the surrounding tissue can reduce the success of minimally invasive surgery.

Performance of a Nonlinear Magnetic Handheld Probe for Intraoperative Sentinel Lymph Node Detection: A Phantom Study

ObjectiveThis study investigates the performance of the DiffMag handheld probe (nonlinear magnetometry), to be used for sentinel lymph node detection. Furthermore, the performance of DiffMag is compared with a gamma probe and a first-order magnetometer (Sentimag®, linear magnetometry).MethodsThe performance of all three probes was evaluated based on longitudinal distance, transverse distance, and resolving power for two tracer volumes. A phantom was developed to investigate the performance of the probes for a clinically relevant situation in the floor of the mouth (FOM).ResultsConsidering the longitudinal distance, both DiffMag handheld and Sentimag® probe had comparable performance, while the gamma probe was able to detect at least a factor of 10 deeper. Transverse distances of 13, 11, and 51 mm were measured for the small tracer volume by the DiffMag handheld, Sentimag®, and the gamma probe, respectively. For the large tracer volume this was 21, 18, and 55 mm, respectively. The full width at half maximum, at 7 mm probe height from the phantom surface, was 14, 12, and 18 mm for the small tracer volume and 15, 18, and 25 mm for the large tracer volume with the DiffMag handheld, Sentimag®, and gamma probe, respectively.ConclusionsWith a high resolving power but limited longitudinal distance, the DiffMag handheld probe seems suitable for detecting SLNs which are in close proximity to the primary tumor. In this study, comparable results were shown using linear magnetometry. The gamma probe reached 10 times deeper, but has a lower resolving power compared with the DiffMag handheld probe.

Simulation study of the effect of the geometrical parameters on the performance of a beta probe

Abstract An intraoperative probe is a small tool used to identify, locate, and dissect pathological lesions during surgery and confirm their removal. The most common type of probe is the gamma probe, which detects gamma-emitting sources. Despite the successful use of gamma probes in clinics, their application can be limited when the background radiation from healthy tissue nearby or the injection site is high. In these cases, the use of beta probes that detect beta-emitting radiotracers would be beneficial. The shorter range of beta radiation compared to gamma radiation would result in improved detection efficacy when background radiation is significant. In this simulation study, we examined how geometrical parameters may impact the performance of a beta probe. Our results showed that the source depth inside the phantom and detector size affected the performance of the beta probe. We also proposed and evaluated two designs of beta probes capable of adjusting their performance.