Treatment of Primary Liver Tumors and Liver Metastases, Part 1: Nuclear Medicine Techniques

90Y post-radioembolization clinical assessment with whole-body Biograph Vision Quadra PET/CT: image quality, tumor, liver and lung dosimetry

PURPOSE

Evaluation of 90Y liver radioembolization post-treatment clinical data using a whole-body Biograph Vision Quadra PET/CT to investigate the potential of protocol optimization in terms of scan time and dosimetry.

METHODS

17 patients with hepatocellular carcinoma with median (IQR) injected activity 2393 (1348-3298) MBq were included. Pre-treatment dosimetry plan was based on 99mTc-MAA SPECT/CT with Simplicit90Y™ and post-treatment validation with Quadra using Simplicit90Y™ and HERMIA independently. Regarding the image analysis, mean and peak SNR, the coefficient of variation (COV) and lesion-to-background ratio (LBR) were evaluated. For the post-treatment dosimetry validation, the mean tumor, whole liver and lung absorbed dose evaluation was performed using Simplicit90Y and HERMES. Images were reconstructed with 20-, 15-, 10-, 5- and 1- min sinograms with 2, 4, 6 and 8 iterations. Wilcoxon signed rank test was used to show statistical significance (p < 0.05).

RESULTS

There was no difference of statistical significance between 20- and 5- min reconstructed times for the peak SNR, COV and LBR. In addition, there was no difference of statistical significance between 20- and 1- min reconstructed times for all dosimetry metrics. Lung dosimetry showed consistently lower values than the expected. Tumor absorbed dose based on Simplicit90Y™ was similar to the expected while HERMES consistently underestimated significantly the measured tumor absorbed dose. Finally, there was no difference of statistical significance between expected and measured tumor, whole liver and lung dose for all reconstruction times.

CONCLUSION

In this study we evaluated, in terms of image quality and dosimetry, whole-body PET clinical images of patients after having been treated with 90Y microspheres radioembolization for liver cancer. Compared to the 20-min standard scan, the simulated 5-min reconstructed images provided equal image peak SNR and noise behavior, while performing also similarly for post-treatment dosimetry of tumor, whole liver and lung absorbed doses.

The Future of Interventions for Stage IV Colorectal Cancers

Future options for the management of stage IV colorectal cancer are primarily focused on personalized and directed therapies. Interventions include precision cancer medicine, utilizing nanocarrier platforms for directed chemotherapy, palliative pressurized intraperitoneal aerosol chemotherapy (PIPAC), adjunctive oncolytic virotherapy, and radioembolization techniques. Comprehensive genetic profiling provides specific tumor-directed therapy based on individual genetics. Biomimetic magnetic nanoparticles as chemotherapy delivery systems may reduce systemic side effects of traditional chemotherapy by targeting tumor cells and sparing healthy cells. PIPAC is a newly emerging option for patients with peritoneal metastasis from colorectal cancer and is now being used internationally, showing promising results as a palliative therapy for colorectal cancer. Oncolytic virotherapy is another emerging potential treatment option, especially when combined with standard chemotherapy and/or radiation, as well as immunotherapy. And finally, radioembolization with yttrium-90 ( 90 Y) microspheres has shown some success in treating patients with unresectable liver metastasis from colorectal cancer via selective arterial injection.

99m Tc-Macroaggregated Albumin Liver Lung Shunt Study With Uptake Indicative of Patent Falciform Artery

ABSTRACT

Intra-arterial injection of radioactive isotope 90-yttrium 90 Y has been used for elective internal radiation therapy for the treatment of localized hepatocellular carcinoma deemed surgically unresectable. It has also been used to treat intrahepatic cholangiocarcinoma and colorectal cancer that has metastasized to the liver. To prepare for 90 Y treatment, preprocedural mapping via hepatic angiography and 99m Tc-macroaggregated albumin liver lung shunt study followed by postprocedural 90 Y SPECT/CT is essential to ensure a targeted therapy. Therapy is contraindicated if lung shunt fraction is greater than 20% for SIR-Spheres. Anatomic variation in hepatic angiography may be present that can lead to complications if unaccounted for.

Outcomes following transarterial radioembolization with 90Y and nanoparticles loaded resin microspheres

⁹⁰Y bremsstrahlung Single-Photon Emission Tomography (SPECT) imaging is employed to check the possibility of extrahepatic uptake and the quantification of delivered dose in Transarterial Radioembolization (TARE). ⁹⁰Y bremsstrahlung SPECT imaging is challenging due to the nature of bremsstrahlung photons. We reported a Monte Carlo study using the resin microspheres loaded with ⁹⁰Y and Nanoparticles (NPs) in the TARE. By injection of Bismuth (Bi) and Europium (Eu) NPs into the resin microspheres, the sensitivity and the contrast to noise ratio increased for the bremsstrahlung planar images. The highest signal to background ratio was observed in the characteristic X-ray planar images taken with the energy window at the Kα₁ ± 10 keV when Eu NPs were incorporated into the microsphere. The dose enhancement ratio decreased dramatically at NP concentrations >2.4 M. Incorporating NPs into the resin microspheres improves the quality of post-treatment images and establishes a standardized imaging protocol for post-treatment imaging by characteristic X-rays.

Minimizing the risk of small-for-size syndrome after liver surgery

BACKGROUND

Primary and secondary liver tumors are not always amenable to resection due to location and size. Inadequate future liver remnant (FLR) may prevent patients from having a curative resection or may result in increased postoperative morbidity and mortality from complications related to small-for-size syndrome (SFSS).

DATA SOURCES

This comprehensive review analyzed the principles, mechanism and risk factors associated with SFSS and presented current available options in the evaluation of FLR when planning liver surgery. In addition, it provided a detailed description of specific modalities that can be used before, during or after surgery, in order to optimize the conditions for a safe resection and minimize the risk of SFSS.

RESULTS

Several methods which aim to reduce tumor burden, preserve healthy liver parenchyma, induce hypertrophy of FLR or prevent postoperative complications help minimize the risk of SFSS.

CONCLUSIONS

With those techniques the indications of radical treatment for patients with liver tumors have significantly expanded. The successful outcome depends on appropriate patient selection, the individualization and modification of interventions and the right timing of surgery.

Mechanistic connections between mitochondrial biology and regulated cell death

The ancient, dynamic, and multifaceted functions of the mitochondrial network are essential for organismal homeostasis and contribute to numerous human diseases. As central hubs for metabolism, ion transport, and multiple macromolecular synthesis pathways, mitochondria establish and control extensive signaling networks to ensure cellular survival. In this review, we explore how these same mitochondrial functions also participate in the control of regulated cell death (RCD). We discuss the complementary essential mitochondrial functions as compartments that participate in the production and presentation of key molecules and platforms that actively enable, initiate, and execute RCD.

High quality imaging and dosimetry for yttrium-90 (90Y) liver radioembolization using a SiPM-based PET/CT scanner

PURPOSE

Transarterial radioembolization (TARE) with yttrium-90 (⁹⁰Y) microspheres is a liver-directed treatment for primary and secondary hepatic malignancies. Personalized dosimetry aims for maximum treatment effect and reduced toxicity. We aimed to compare pre-treatment voxel-based dosimetry from ^99mTc macroaggregated albumin (MAA) SPECT/CT with post-treatment ⁹⁰Y PET/CT for absorbed dose values, and to evaluate image quality of ⁹⁰Y SiPM-based PET/CT.

METHODS

Forty-two patients (28 men, 14 women, mean age: 67 ± 11 years) with advanced hepatic malignancies were prospectively enrolled. Twenty patients were treated with glass and 22 with resin microspheres. Radiation absorbed doses from planning ^99mTc-MAA SPECT/CT and post-therapy ⁹⁰Y PET/CT were assessed. ⁹⁰Y PET/CT images were acquired for 20 min and reconstructed to produce 5-, 10-, 15-, and 20-min datasets, then evaluated using the 5-point Likert scale.

RESULTS

The mean administered activity was 3.44 ± 1.5 GBq for glass and 1.62 ± 0.7 GBq for resin microspheres. The mean tumor absorbed doses calculated from ^99mTc-MAA SPECT/CT and ⁹⁰Y PET/CT were 175.69 ± 113.76 Gy and 193.58 ± 111.09 Gy (P = 0.61), respectively for glass microspheres; they were 60.18 ± 42.20 Gy and 70.98 ± 49.65 Gy (P = 0.37), respectively for resin microspheres. The mean normal liver absorbed doses from ^99mTc-MAA SPECT/CT and ⁹⁰Y PET/CT were 32.70 ± 22.25 Gy and 30.62 ± 20.09 Gy (P = 0.77), respectively for glass microspheres; they were 18.33 ± 11.08 Gy and 24.32 ± 15.58 Gy (P = 0.17), respectively for resin microspheres. Image quality of ⁹⁰Y PET/CT at 5-, 10-, 15-, and 20-min scan time showed a Likert score of 3.6 ± 0.54, 4.57 ± 0.58, 4.84 ± 0.37, and 4.9 ± 0.3, respectively.

CONCLUSIONS

^99mTc-MAA SPECT/CT demonstrated great accuracy for treatment planning dosimetry. SiPM-based PET/CT scanner showed good image quality at 10-min scan time, acquired in one bed position. A PET/CT scan time of 5 min showed acceptable image quality and suffices for dosimetry and treatment verification. This allows for inclusion of ⁹⁰Y PET/CT in busy routine clinical workflows. Studies with larger patient cohorts are needed to confirm these findings.

Radioembolization for the Treatment of Primary and Metastatic Liver Cancers

Radioembolization using ⁹⁰Y microspheres (glass or resin) has been introduced as an effective intraarterial therapy for unresectable primary and metastatic liver cancers. Although the basic therapeutic effect of chemoembolization results from ischemia, the therapeutic efficacy of radioembolization comes from radiation. Furthermore, compared with surgical resection and local ablation therapy, radioembolization is available with less limitation on the sites or number of liver cancers. The radioisotope ⁹⁰Y is a β-radiation emitter without γ-radiation, with the emission of secondary bremsstrahlung photons and small numbers of positrons. Administration of ⁹⁰Y microspheres into the hepatic artery can deliver a high dose of radiation selectively to the target tumor with limited radiation exposure to the surrounding normal parenchyma, and has low systemic toxicity. In general, radioembolization has been considered for patients with unresectable primary or metastatic liver-only or liver-dominant cancers with no ascites or other clinical signs of liver failure, life expectancy of > 12 weeks, and good performance status. Here, we review the current radioactive compounds, pretreatment assessment, and indications for radioembolization in patients with hepatocellular carcinoma, intrahepatic cholangiocarcinoma, and liver metastases from colorectal cancer.