Y90-radioembolization of lung metastases via the bronchial artery: a report of 2 cases

New frontiers in radioembolization

Radioembolization is a locoregional transarterial therapy that combines radionuclide and micron-sized beads to deliver radiation internally to the target tumors based on the arterial blood flow. While initially developed as a palliative treatment option, radioembolization is now used for curative intent treatment, neoadjuvant therapy, and method to downstage or bridge for liver transplant. Radioembolization has become increasingly utilized and is an important therapeutic option for the management of hepatocellular carcinoma and liver metastasis. This article provides an overview of the techniques, challenges, and novel developments in radioembolization, including new dosimetry techniques, radionuclides, and new target tumors.

Extrahepatic Applications of Yttrium-90 Radioembolization

While initially described and now accepted as treatment for primary and secondary malignancies in the liver, radioembolization therapy has expanded to include treatment for other disease pathologies and other organ systems. Advantages and limitations for these treatments exist and must be compared against more traditional treatments for these processes. This article provides an overview of the current applications for radioembolization outside of the liver, for both malignant and nonmalignant disease.

Embolization of Chest Neoplasms: The Next Frontier in Interventional Oncology?

The management of chest tumors and their sequelae has been an uncommon indication for transarterial embolization (TAE). More recently, vascular embolization has been increasingly performed for this indication. The most common reported indication for embolization of neoplastic disease in the chest is the control of bleeding resulting either from iatrogenic causes or from tumor invasion into a bronchus or vessel. A natural extension of the application of TAE to neoplasm-related hemoptysis is its burgeoning indication as a possible primary treatment for benign chest tumors, primary lung neoplasms, and metastatic disease in patients that are refractory to systemic therapies and have limited or no surgical options. The goals for this indication are tumor regression and management of bulk-related symptoms. In addition to bland TAE for this indication, authors have reported very initial results applying transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) to chest neoplasms with promising results that support feasibility and safety. This article is an up-to-date review of the management of chest tumors with embolization and its variants.

A review of 3D image-based dosimetry, technical considerations and emerging perspectives in 90Y microsphere therapy

Yttrium-90 radioembolization (⁹⁰Y-RE) is a well-established therapy for the treatment of hepatocellular carcinoma (HCC) and also of metastatic liver deposits from other malignancies. Nuclear Medicine and Cath Lab diagnostic imaging takes a pivotal role in the success of the treatment, and in order to fully exploit the efficacy of the technique and provide reliable quantitative dosimetry that are related to clinical endpoints in the era of personalized medicine, technical challenges in imaging need to be overcome. In this paper, the extensive literature of current ⁹⁰Y-RE techniques and challenges facing it in terms of quantification and dosimetry are reviewed, with a focus on the current generation of 3D dosimetry techniques. Finally, new emerging techniques are reviewed which seek to overcome these challenges, such as high-resolution imaging, novel surgical procedures and the use of other radiopharmaceuticals for therapy and pre-therapeutic planning.

Yttrium-90 microspheres: a review of its emerging clinical indications

BACKGROUND

Many patients with liver malignancies are not candidates for resection, and systemic therapies are often not effective. Radioembolization (RE) is an alternative treatment for this group of patients. The safety and efficacy of RE with yttrium 90 (Y90) in patients with hepatocellular carcinoma (HCC) or metastatic colon cancer to the liver have been proven in several studies. However, fewer studies have focussed on the safety and efficacy of RE with Y90 in other extrahepatic primary and secondary liver cancers. The effect on outcomes of concomitant use of Y90 with a systemic therapy is still currently under investigation.

SUMMARY

A review of the published data on the use of RE as stand-alone, concomitant or sequential with other treatment modalities in HCC and other primary and secondary liver cancer is reported here.

KEY MESSAGE

RE for the treatment of HCC and other extrahepatic, primary and secondary liver cancer has reasonable efficacy and acceptable toxicities. Definitive studies to establish the role of RE in the treatment of such malignancies are warranted.

Beyond hepatocellular carcinoma and colorectal metastasis: the expanding applications of radioembolization

As a relatively safe outpatient procedure, radioembolization can potentially be used to treat any type of tumor within the liver, primary or metastatic. The safety and effectiveness of radioembolization in the treatment of hepatocellular carcinoma (HCC) and metastatic colorectal cancer (mCRC) has led many groups to explore its application in other malignancies. Moreover, other organs, such as the lungs and kidneys, have been explored as targets for therapy. Although the most data for radioembolization is related to HCC and mCRC, there is increasing experience and data regarding metastatic disease to the liver for other primary tumors. We review the current state of liver-directed therapy with radioembolization outside of HCC and mCRC, including metastatic neuroendocrine, breast, and melanoma, as well as limited experiences with other primary malignancies. Applications of radioembolization related to these other cancers and new trends and future directions will be discussed. With increasing use and availability of radioembolization, it promises to serve an expanding role in the repertoire of tools available for treating and managing oncologic disease.

Post-radioembolization yttrium-90 PET/CT - part 1: diagnostic reporting

Background

Yttrium-90 (⁹⁰Y) positron emission tomography with integrated computed tomography (PET/CT) represents a technological leap from ⁹⁰Y bremsstrahlung single-photon emission computed tomography with integrated computed tomography (SPECT/CT) by coincidence imaging of low abundance internal pair production. Encouraged by favorable early experiences, we implemented post-radioembolization ⁹⁰Y PET/CT as an adjunct to ⁹⁰Y bremsstrahlung SPECT/CT in diagnostic reporting.

Methods

This is a retrospective review of all paired ⁹⁰Y PET/CT and ⁹⁰Y bremsstrahlung SPECT/CT scans over a 1-year period. We compared image resolution, ability to confirm technical success, detection of non-target activity, and providing conclusive information about ⁹⁰Y activity within targeted tumor vascular thrombosis. ⁹⁰Y resin microspheres were used. ⁹⁰Y PET/CT was performed on a conventional time-of-flight lutetium-yttrium-oxyorthosilicate scanner with minor modifications to acquisition and reconstruction parameters. Specific findings on ⁹⁰Y PET/CT were corroborated by ⁹⁰Y bremsstrahlung SPECT/CT, ^99mTc macroaggregated albumin SPECT/CT, follow-up diagnostic imaging or review of clinical records.

Results

Diagnostic reporting recommendations were developed from our collective experience across 44 paired scans. Emphasis on the continuity of care improved overall diagnostic accuracy and reporting confidence of the operator. With proper technique, the presence of background noise did not pose a problem for diagnostic reporting. A counter-intuitive but effective technique of detecting non-target activity is proposed, based on the pattern of activity and its relation to underlying anatomy, instead of its visual intensity. In a sub-analysis of 23 patients with a median follow-up of 5.4 months, ⁹⁰Y PET/CT consistently outperformed ⁹⁰Y bremsstrahlung SPECT/CT in all aspects of qualitative analysis, including assessment for non-target activity and tumor vascular thrombosis. Parts of viscera closely adjacent to the liver remain challenging for non-target activity detection, compounded by a tendency for mis-registration.

Conclusions

Adherence to proper diagnostic reporting technique and emphasis on continuity of care are vital to the clinical utility of post-radioembolization ⁹⁰Y PET/CT. ⁹⁰Y PET/CT is superior to ⁹⁰Y bremsstrahlung SPECT/CT for the assessment of target and non-target activity.