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Determination of Radiation Absorbed Dose to Primary Liver Tumors and Normal Liver Tissue Using Post-Radioembolization (90)Y PET.

Srinivas SM, Natarajan N, Kuroiwa J, Gallagher S, Nasr E, Shah SN, DiFilippo FP, Obuchowski N, Bazerbashi B, Yu N, McLennan G - Front Oncol (2014)

Bottom Line: Normal liver tissue received a mean dose of 67 Gy (mode 60-70 Gy; range 10-120 Gy).There was a statistically significant association between absorbed dose to normal liver and the presence of two or more severe complications (p = 0.036).Collateral dose to normal liver is non-trivial and can have clinical implications.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Medicine, Cleveland Clinic , Cleveland, OH , USA.

ABSTRACT

Background: Radioembolization with Yttrium-90 ((90) Y) microspheres is becoming a more widely used transcatheter treatment for unresectable hepatocellular carcinoma (HCC). Using post-treatment (90) Y positron emission tomography/computerized tomography (PET/CT) scans, the distribution of microspheres within the liver can be determined and quantitatively assessed. We studied the radiation dose of (90) Y delivered to liver and treated tumors.

Methods: This retrospective study of 56 patients with HCC, including analysis of 98 liver tumors, measured and correlated the dose of radiation delivered to liver tumors and normal liver tissue using glass microspheres (TheraSpheres(®)) to the frequency of complications with modified response evaluation criteria in solid tumors (mRECIST). (90) Y PET/CT and triphasic liver CT scans were used to contour treated tumor and normal liver regions and determine their respective activity concentrations. An absorbed dose factor was used to convert the measured activity concentration (Bq/mL) to an absorbed dose (Gy).

Results: The 98 studied tumors received a mean dose of 169 Gy (mode 90-120 Gy; range 0-570 Gy). Tumor response by mRECIST criteria was performed for 48 tumors that had follow-up scans. There were 21 responders (mean dose 215 Gy) and 27 non-responders (mean dose 167 Gy). The association between mean tumor absorbed dose and response suggests a trend but did not reach statistical significance (p = 0.099). Normal liver tissue received a mean dose of 67 Gy (mode 60-70 Gy; range 10-120 Gy). There was a statistically significant association between absorbed dose to normal liver and the presence of two or more severe complications (p = 0.036).

Conclusion: Our cohort of patients showed a possible dose-response trend for the tumors. Collateral dose to normal liver is non-trivial and can have clinical implications. These methods help us understand whether patient adverse events, treatment success, or treatment failure can be attributed to the dose that the tumor or normal liver received.

No MeSH data available.


Related in: MedlinePlus

This image shows a contour in pink drawn around a treated region in an axial slice of the AC CT/PET fusion image that was acquired following right lobe 90Y microsphere therapy.
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Figure 1: This image shows a contour in pink drawn around a treated region in an axial slice of the AC CT/PET fusion image that was acquired following right lobe 90Y microsphere therapy.

Mentions: The attenuation correction CT (AC CT) that is acquired with the PET scan following 90Y radioembolization was used to contour the volume of treated liver (i.e., right lobe or left lobe). The 90Y PET scan and the accompanying AC CT were analyzed using MIM software. A fusion of the PET and AC CT was viewed in order to visualize which regions of the liver were targeted and contained the most activity. The treated lobe volume was contoured on the AC CT using a contour tool in MIM. Contours were individually drawn in the axial view of the AC CT. Contours were drawn on each plane to ensure that the entire treated region was encompassed. The region of treatment was determined by examining the 90Y PET activity distribution on the fusion image and also by viewing medical records of the 90Y microsphere therapy procedure that indicated the intended target liver lobes for therapy. After the contours were drawn, the contour statistics tool in MIM was used to display the volume of the contour region in mL and the activity concentration of the contour region in Bq/mL (see Figure 1). Three trainees contoured both liver and tumor volumes under the supervision of a board certified nuclear medicine physician.


Determination of Radiation Absorbed Dose to Primary Liver Tumors and Normal Liver Tissue Using Post-Radioembolization (90)Y PET.

Srinivas SM, Natarajan N, Kuroiwa J, Gallagher S, Nasr E, Shah SN, DiFilippo FP, Obuchowski N, Bazerbashi B, Yu N, McLennan G - Front Oncol (2014)

This image shows a contour in pink drawn around a treated region in an axial slice of the AC CT/PET fusion image that was acquired following right lobe 90Y microsphere therapy.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4195277&req=5

Figure 1: This image shows a contour in pink drawn around a treated region in an axial slice of the AC CT/PET fusion image that was acquired following right lobe 90Y microsphere therapy.
Mentions: The attenuation correction CT (AC CT) that is acquired with the PET scan following 90Y radioembolization was used to contour the volume of treated liver (i.e., right lobe or left lobe). The 90Y PET scan and the accompanying AC CT were analyzed using MIM software. A fusion of the PET and AC CT was viewed in order to visualize which regions of the liver were targeted and contained the most activity. The treated lobe volume was contoured on the AC CT using a contour tool in MIM. Contours were individually drawn in the axial view of the AC CT. Contours were drawn on each plane to ensure that the entire treated region was encompassed. The region of treatment was determined by examining the 90Y PET activity distribution on the fusion image and also by viewing medical records of the 90Y microsphere therapy procedure that indicated the intended target liver lobes for therapy. After the contours were drawn, the contour statistics tool in MIM was used to display the volume of the contour region in mL and the activity concentration of the contour region in Bq/mL (see Figure 1). Three trainees contoured both liver and tumor volumes under the supervision of a board certified nuclear medicine physician.

Bottom Line: Normal liver tissue received a mean dose of 67 Gy (mode 60-70 Gy; range 10-120 Gy).There was a statistically significant association between absorbed dose to normal liver and the presence of two or more severe complications (p = 0.036).Collateral dose to normal liver is non-trivial and can have clinical implications.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Medicine, Cleveland Clinic , Cleveland, OH , USA.

ABSTRACT

Background: Radioembolization with Yttrium-90 ((90) Y) microspheres is becoming a more widely used transcatheter treatment for unresectable hepatocellular carcinoma (HCC). Using post-treatment (90) Y positron emission tomography/computerized tomography (PET/CT) scans, the distribution of microspheres within the liver can be determined and quantitatively assessed. We studied the radiation dose of (90) Y delivered to liver and treated tumors.

Methods: This retrospective study of 56 patients with HCC, including analysis of 98 liver tumors, measured and correlated the dose of radiation delivered to liver tumors and normal liver tissue using glass microspheres (TheraSpheres(®)) to the frequency of complications with modified response evaluation criteria in solid tumors (mRECIST). (90) Y PET/CT and triphasic liver CT scans were used to contour treated tumor and normal liver regions and determine their respective activity concentrations. An absorbed dose factor was used to convert the measured activity concentration (Bq/mL) to an absorbed dose (Gy).

Results: The 98 studied tumors received a mean dose of 169 Gy (mode 90-120 Gy; range 0-570 Gy). Tumor response by mRECIST criteria was performed for 48 tumors that had follow-up scans. There were 21 responders (mean dose 215 Gy) and 27 non-responders (mean dose 167 Gy). The association between mean tumor absorbed dose and response suggests a trend but did not reach statistical significance (p = 0.099). Normal liver tissue received a mean dose of 67 Gy (mode 60-70 Gy; range 10-120 Gy). There was a statistically significant association between absorbed dose to normal liver and the presence of two or more severe complications (p = 0.036).

Conclusion: Our cohort of patients showed a possible dose-response trend for the tumors. Collateral dose to normal liver is non-trivial and can have clinical implications. These methods help us understand whether patient adverse events, treatment success, or treatment failure can be attributed to the dose that the tumor or normal liver received.

No MeSH data available.


Related in: MedlinePlus