A simplified technique to resect abnormal bony radiolocalizations using a gamma counter

Interventional nuclear medicine: a focus on radioguided intervention and surgery

Within interventional nuclear medicine (iNM) a prominent role is allocated for the sub-discipline of radioguided surgery. Unique for this discipline is the fact that an increasing number of clinical indications (e.g. lymphatic mapping, local tumor demarcation and/or tumor receptor targeted applications) have been adopted into routine care. The clinical integration is further strengthened by technical innovations in chemistry and engineering that enhance the translational potential of radioguided procedures in iNM. Together, these features not only ensure ongoing expansion of iNM but also warrant a lasting clinical impact for the sub-discipline of radioguided surgery.

Recent advances in nuclear and hybrid detection modalities for image-guided surgery

Introduction: Radioguided surgery is an ever-evolving part of nuclear medicine. In fact, this nuclear medicine sub-discipline actively bridges non-invasive molecular imaging with surgical care. Next to relying on the availability of radio- and bimodal-tracers, the success of radioguided surgery is for a large part dependent on the imaging modalities and imaging concepts available for the surgical setting. With this review, we have aimed to provide a comprehensive update of the most recent advances in the field. Areas covered: We have made an attempt to cover all aspects of radioguided surgery: 1) the use of radioisotopes that emit γ, β⁺, and/or β^- radiation, 2) hardware developments ranging from probes to 2D cameras and even the use of advanced 3D interventional imaging solutions, and 3) multiplexing solutions such as dual-isotope detection or combined radionuclear and optical detection. Expert opinion: Technical refinements in the field of radioguided surgery should continue to focus on supporting its implementation in the increasingly complex minimally invasive surgical setting, e.g. by accommodating robot-assisted laparoscopic surgery. In addition, hybrid concepts that integrate the use of radioisotopes with other image-guided surgery modalities such as fluorescence or ultrasound are likely to expand in the future.

Use of the navigator probe after radiotracer injection to identify nonpalpable rib lesions requiring surgical resection

BACKGROUND

: Patients with nonpalpable rib lesions (NPRL) requiring biopsy present a challenging problem for the thoracic surgeon. Ideally, a small incision directly over the NPRL should be performed to minimize morbidity, particularly if the lesion is benign. The Navigator probe is routinely used after lymphoscintigraphy by surgical oncologists to isolate sentinel lymph nodes requiring removal, but can also be used to guide resection of nonpalpable focal rib lesions demonstrating increased technetium-99m hydroxymethylene diphosphonate (Tc-99m HDP) uptake. This report describes our initial experience with this technique.

METHODS

: Over a 5-month period, 3 patients with focal NPRL underwent rib resection. All patients had solitary lesions demonstrated on recently performed Tc-99m HDP bone scanning. Prior cancers were reported in 2 patients, and pain in 2 patients. Before surgery, all patients underwent intravenous injection of 20 to 25 mCi Tc-99m HDP at least 2 hours before the Navigator probe-guided procedure.

RESULTS

: The Navigator probe identified all 3 lesions, allowing a single 4 cm or smaller incision in all cases. Histology included metastatic breast cancer (1), pathologic fracture secondary to metastatic palatal cancer (1), and eosinophilic granuloma (1). No patient required further resection.

CONCLUSIONS

: Intraoperative localization of NPRL that are positive on Tc-99m HDP bone scanning using the Navigator probe is feasible and was 100% successful in our initial experience. This technique allows a minimally invasive approach, which is beneficial for those patients who do not require further resection.

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology.

Sentinel lymph node biopsy for breast cancer

This manuscript is a brief discussion of the developments of the technology and concepts that led to modern procedures of radiotracer guided surgery of sentinel nodes (SNs) for breast cancer. The past section highlights some of the contributions by key persons involved with SN methods. The present section describes the magnitude of types of published material to date. The future section describes the major international trials and some important technical challenges yet to be solved.

Gamma probe assisted biopsy of suspected metastatic rib lesions

Retrieving diagnostic tissue from a rib lesion can be challenging. Using a hand-held intraoperative gamma probe to target and biopsy the areas of increased radioisotope uptake has been limited largely to use by thoracic surgeons and interventional radiologists. Such techniques also have been used by orthopaedic oncologists in localizing osteoid osteomas. We pursued a similar technique in localizing the rib lesion. During the 10 months, two patients with a history of cancer and recent bone scans indicative of possible rib metastasis required biopsies for definitive tissue diagnosis. Both patients had gamma-probe localization of their rib lesions intraoperatively using minimally invasive techniques. The operation of the probe was simple with a short learning curve. Both patients had biopsies that yielded diagnoses verifying the abnormality on the staging bone scan. Localization was sensitive and accurate with histologic confirmation in both patients. The length and extent of surgery were markedly reduced with no complications. These results match those reported in the literature by thoracic surgeons and radiologists. The hand-held gamma probe assisted biopsy of suspicious rib abnormalities can be an effective surgical technique that the orthopaedic surgeon should consider. Additional experience with the technique will allow an assessment of the sensitivity and specificity.

Candidate???s Thesis: The Application of Sentinel Node Radiolocalization to Solid Tumors of the Head and Neck: A 10-Year Experience

OBJECTIVES/HYPOTHESIS

The goals of the research study were to develop an easily mastered, accurate, minimally invasive technique of sentinel node radiolocalization with biopsy (SNRLB) in the feline model; to compare it with blue-dye mapping techniques; and to test the applicability of sentinel node radiolocalization biopsy in three head and neck tumor types: N0 malignant melanoma, N0 Merkel cell carcinoma, and N0 squamous cell carcinoma.

STUDY DESIGN

Prospective consecutive series studies were performed in the feline model and in three head and neck tumor types: N0 malignant melanoma (43 patients), N0 Merkel cell carcinoma (8 patients), and N0 squamous cell carcinoma (20 patients).

METHODS

The technique of sentinel node radiolocalization with biopsy was analyzed in eight felines and compared with blue-dye mapping. Patterns of sentinel node gamma emissions were recorded. Localization success rates were determined for blue dye and sentinel node with radiolocalization biopsy. In the human studies, all patients had sentinel node radiolocalization biopsy performed in a similar manner. On the morning of surgery, each patient had sentinel node radiolocalization biopsy of the sentinel lymph node performed using an intradermal or peritumoral injection of technetium Tc 99m sulfur colloid. Sentinel nodes were localized on the skin surface using a handheld gamma detector. Gamma count measurements were obtained for the following: 1) the "hot" spot/node in vivo before incision, 2) the hot spot/node in vivo during dissection, 3) the hot spot/node ex vivo, 4) the lymphatic bed after hot spot/node removal, and 5) the background in the operating room. The first draining lymph node(s) was identified, and biopsy of the node was performed. The radioactive sentinel lymph node(s) was submitted separately for routine histopathological evaluation. Preoperative lymphoscintigrams were performed in patients with melanoma and patients with Merkel cell carcinoma. In patients with head and neck squamous cell carcinoma, the relationship between the sentinel node and the remaining lymphatic basin was studied and all patients received complete neck dissections. The accuracy of sentinel node radiolocalization with biopsy, the micrometastatic rate, the false-negative rate, and long-term recurrence rates were reported for each of the head and neck tumor types. In the melanoma study, the success of sentinel node localization was compared for sentinel node radiolocalization biopsy, blue-dye mapping, and lymphoscintigraphy. In the Merkel cell carcinoma study, localization rates were evaluated for sentinel node radiolocalization biopsy and lymphoscintigraphy. In the head and neck squamous cell carcinoma study, the localization rate of sentinel node radiolocalization biopsy and the predictive value of the sentinel node relative to the remaining lymphatic bed were determined. All results were analyzed statistically.

RESULTS

Across the different head and neck tumor types studied, sentinel node radiolocalization biopsy had a success rate approaching 95%. Sentinel node radiolocalization biopsy was more successful than blue-dye mapping or lymphoscintigraphy at identifying the sentinel node, although all three techniques were complementary. There was no instance of a sentinel node-negative patient developing regional lymphatic recurrence. In the head and neck squamous cell carcinoma study, there was no instance in which the sentinel node was negative and the remaining lymphadenectomy specimen was positive.

CONCLUSION

In head and neck tumors that spread via the lymphatics, it appears that sentinel node radiolocalization biopsy can be performed with a high success rate. This technique has a low false-negative rate and can be performed through a small incision. In head and neck squamous cell carcinoma, the histological appearance of the sentinel node does appear to reflect the regional nodal status of the patient.

Enhanced localization of osteoid osteoma with radiolabeling and intraoperative gamma counter guidance: a case report

Osteoid osteoma is a benign bone tumor that can be removed by marginal excision. Excessive removal of reactive bone may result in significant morbidity. We made use of the highly specific radioactive technetium uptake characteristic of osteoid osteoma for its localization. Radioactive technetium (25 mCi) was injected intravenously 2 hours before surgery to a 21-year-old male patient with an osteoid osteoma over the left distal radius. Tumor tissue was localized intraoperatively by a portable hand-held radioactive gamma counter to detect a focal high intensity of radioactivity. Complete tumor removal was shown by reduction of radioactivity to background level. This was confirmed by bone scintigraphy of the specimen and the forearm immediately after surgery. The defect was packed with cancellous bone graft taken from the ipsilateral distal radius through the same wound. Postoperative recovery was very satisfactory. We found this approach useful in limiting resection margin and surgical site morbidity in resection of osteoid osteoma.

Radioisotope-guided surgical biopsy of costal metastases in breast cancer patients

Radioisotope bone scanning is a sensitive indicator of metastatic disease. Localization of the hot spot for biopsy is difficult. Today, a hand-held gamma probe enables the surgeon intraoperatively to accomplish the localization procedure easily. As this technique is described in American literature exclusively, more recent European findings is presented here. During one month two patients were diagnosed with breast cancer. Bone scanning disclosed minor hot spots in the ribs. On the day of surgical biopsy the localization of the hot spots was guided by a gamma probe. For the biopsy a dermal punch biopsy needle was employed, and fine needle aspiration biopsies were also taken. The procedures were easy and completed within a few minutes. The post-operative courses were uneventful. In one patient, final histology showed malignancy in both biopsies. In the other patient, only the fine needle aspiration biopsy was malignant. The punch biopsy was abnormal, but did not contain malignant tissue. The gamma probe is an important tool in the performance of rib biopsies of nonpalpable lesions. The punch biopsy technique is simple and combined with fine needle aspiration biopsy the method has proven to be sensitive and accurate. The punch biopsy technique furthermore reduces the risk of postoperative pneumothorax.

Target-specific rib biopsy using the gamma probe

BACKGROUND

Intraoperative localization of rib abnormalities identified on bone scan can be deceptively difficult. Previously used techniques have had limited sensitivity and accuracy. The gamma probe can help localize these bone scan "hot spots."

METHODS

Over the past 17 months, 5 patients underwent gamma-probe-directed limited rib resections following intravenous administration of Tc99m-MDP. Three patients required biopsies for suspected malignancy, and the other 2 underwent therapeutic resections for pain. The device was easy to work with following minimal training.

RESULTS

Localization was excellent, limiting the extent of surgery needed. Comparison with rib counting and preoperative bone scan localization showed a discrepancy of up to 13 cm. Sensitivity and accuracy were each 100%.

CONCLUSIONS

The gamma probe offers a simple and significant advance in the performance of rib biopsies for nonpalpable lesions.

Nuclear medicine and the surgeon

Nuclear medicine provides the surgeon with important diagnostic and functional information on specific organs and with therapy for a limited set of diseases. Clinical applications of nuclear medicine are beginning to guide surgeons to specific locations, notably to sentinel lymph nodes in patients with cancer. The role of radionuclide diagnosis in oncology has been covered earlier in this Lancet series, so here is a surgeon's perspective on sentinel node and other oncological applications and on the surgical value of nuclear medicine in non-malignant diseases.

Gamma-probe-guided lymph node localization in malignant melanoma

The initial draining lymph node (sentinel node) has been successfully localized using intraoperative vital dye mapping and reportedly is predictive of regional nodal metastases in Clinical- Stage 1 melanoma. In an animal model, we previously established the technique of gamma-probe-guided localization of the technetium-99 sulfur colloid labelled sentinel node and found its sensitivity equal to vital dye mapping. We now report our initial experience using gamma-probe-guided localization to identify and then surgically remove the first draining lymph node(s) in 10 malignant melanoma patients. Lymphoscintigraphy was used to confirm localization. We conclude that this technique: (a) reliably localizes the sentinel node draining the site of a primary melanoma, (b) allows the lymphatic bed to be checked intraoperatively verifying complete sentinel node biopsy, and (c) is relatively simple and can be performed under local anaesthesia.

Gamma-probe guided localization of lymph nodes

The initial draining lymph node (Sentinel node) of a tumour may reflect the status of the tumours spread to the remaining lymphatic bed. The sentinel node, which has been reported to predict metastatic melanoma, has recently been localized by a new invasive technique [1]. The goal of our pre-clinical trial was to test a non-invasive technique to localize the sentinel node. Gamma-probe guided localization was used to identify and then surgically remove the first draining lymph node(s) in 16 inguinal lymphatic basins of eight cats. This method was found to be comparable to an invasive method using a blue dye. Gamma-probe localization has several potential advantages in that it can: (a) precisely locate on the surface of the skin the position of an underlying lymph node, (b) intraoperatively guide the surgeon to the lymph node during dissection, (c) verify that the correct node has been biopsied, (d) determine the possible presence of residual lymph nodes, (e) allow lymph nodes to be harvested through a small incision as opposed to raising a skin flap, and (f) be rapidly and easily performed.