Effective dose for multiple and repeated radiation examinations in donors and recipients of adult-to-adult living donor liver transplants at a single center

Radiation exposure from radiological procedures in liver transplant candidates with hepatocellular carcinoma

PURPOSE

Candidates for liver transplantation (LT) with hepatocellular carcinoma (HCC) undergo a large number of diagnostic and interventional radiology procedures. A significant proportion of such procedures involve ionizing radiation with increased lifetime risk of cancer. The objective of our study was to review LT candidates with HCC to quantify ionizing radiation doses from different radiology procedures performed at a single transplant center.

METHOD

We retrospectively reviewed 179 adult patients with HCC (median age 58.6 years [IQR, 55-62]; 155 [86.6%] males) who were accepted for LT between April 2010 and Dec 2018. Radiology procedures and radiation doses were retrieved and the total and median radiation effective dose in millisieverts (mSv) were calculated for different procedures. Exposure to ionizing radiation was categorized based on previously reported thresholds.

RESULTS

We assessed 9,986 radiology procedures for our cohort. Patients had a median effective dose prior to transplantation of 254 mSv (IQR, 130-421) with an annualized rate of 152 mSv (IQR, 92-266). Patient median dose increased to 316 mSv (IQR, 159-478) when including exposures post-LT within the study period. 85% of overall exposure was in the extremely high exposure category (>100 mSv). Interventional procedures represented 13% of procedures with substantial radiation and contributed to 45% of radiation exposure while abdominal CTs represented 39% of total procedures and contributed to 45% of radiation exposure.

CONCLUSIONS

Patients with HCC considered for LT undergo radiology procedures with significant cumulative radiation exposure. Attempts to reduce radiation exposure are suggested by minimizing unnecessary procedures and utilizing ones without ionizing radiation. Improving interventional techniques to reduce radiation doses is needed without compromising treatment delivery.

Increasing radiation exposure from computed tomography in liver transplant recipients over time

OBJECTIVES

To evaluate changes in radiation exposure from computed tomography (CT) among patients undergoing liver transplantation in our unit over a 10-year period.

METHODS

We evaluated 134 elective patients, without hepatocellular carcinoma or cholangiocarcinoma who underwent transplantation in 2007-2008 and 2017-2018. CT scans performed in our hospital up to 2 years pre transplant and 1 year post transplant were evaluated.

RESULTS

There was an increase in mean estimated effective radiation dose per patient in 2017-2018 compared to 2007-2008 (77.8 mSv ± 6.2 vs 56.7 mSv ± 5.9, p < 0.05). This change was mainly due to an increased number of pre-transplant CT scans per patient (2.9 ± 0.3 vs 1.4 ± 0.14, p = 0.0001). High radiation dose scan protocols were more frequently used in 2017-2018, with 4-phase liver CT accounting for a larger proportion of scans both pre-transplant (61% vs 43%, p = 0.004) and post-transplant (29% vs 13%, p = 0.002). A greater proportion of patients were exposed to > 100 mSv of ionising radiation in the 2017-2018 patients (29% vs 11%, p < 0.01). These figures are likely to be a significant under-estimate as they exclude other imaging modalities and CT scans performed at other institutions.

CONCLUSION

Radiation exposure from diagnostic imaging has increased among liver transplant recipients at our institution over the last decade. This appears to be due to an increase in the number of CT scans performed, and a shift towards higher dose scan protocols.