Lung Dose Calculation With SPECT/CT for {sup 90}Yittrium Radioembolization of Liver Cancer

Journal Article · Fri Mar 01 04:00:00 EST 2013 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2012.06.051· OSTI ID:22224389

Yu, Naichang ^[1]; Srinivas, Shaym M.; DiFilippo, Frank P.; Shrikanthan, Sankaran ^[2]; Levitin, Abraham; McLennan, Gordon; Spain, James ^[3]; Xia, Ping; Wilkinson, Allan ^[1]

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1. Department of Radiation Oncology, Cleveland Clinic, Cleveland, OH (United States)
2. Department of Nuclear Medicine, Cleveland Clinic, Cleveland, OH (United States)
3. Department of Interventional Radiology, Cleveland Clinic, Cleveland, OH (United States)

Purpose: To propose a new method to estimate lung mean dose (LMD) using technetium-99m labeled macroaggregated albumin ({sup 99m}Tc-MAA) single photon emission CT (SPECT)/CT for {sup 90}Yttrium radioembolization of liver tumors and to compare the LMD estimated using SPECT/CT with clinical estimates of LMD using planar gamma scintigraphy (PS). Methods and Materials: Images of 71 patients who had SPECT/CT and PS images of {sup 99m}Tc-MAA acquired before TheraSphere radioembolization of liver cancer were analyzed retrospectively. LMD was calculated from the PS-based lung shunt assuming a lung mass of 1 kg and 50 Gy per GBq of injected activity shunted to the lung. For the SPECT/CT-based estimate, the LMD was calculated with the activity concentration and lung volume derived from SPECT/CT. The effect of attenuation correction and the patient's breathing on the calculated LMD was studied with the SPECT/CT. With these effects correctly taken into account in a more rigorous fashion, we compared the LMD calculated with SPECT/CT with the LMD calculated with PS. Results: The mean dose to the central region of the lung leads to a more accurate estimate of LMD. Inclusion of the lung region around the diaphragm in the calculation leads to an overestimate of LMD due to the misregistration of the liver activity to the lung from the patient's breathing. LMD calculated based on PS is a poor predictor of the actual LMD. For the subpopulation with large lung shunt, the mean overestimation from the PS method for the lung shunt was 170%. Conclusions: A new method of calculating the LMD for TheraSphere and SIR-Spheres radioembolization of liver cancer based on {sup 99m}Tc-MAA SPECT/CT is presented. The new method provides a more accurate estimate of radiation risk to the lungs. For patients with a large lung shunt calculated from PS, a recalculation of LMD based on SPECT/CT is recommended.

• OSTI ID: 22224389
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 85; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ALBUMINS
BYPASSES
CONCENTRATION RATIO
DIAPHRAGM
IMAGES
LIVER
LUNGS
NEOPLASMS
PATIENTS
PHOTON EMISSION
RADIATION DOSES
RADIOEMBOLIZATION
RESPIRATION
SCINTISCANNING
SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY
TECHNETIUM 99