Purpose: The purpose of this work was to define the temporal CT characteris
tics of hepatic and renal ablation following point-source radioablation uti
lizing a low energy, photon X-ray source emitted from a miniature probe.
Method: Twelve mongrel dogs underwent each of three hepatic and two renal p
oint-source radiation ablations. Animals underwent serial, dual phase, spir
al CT scans and were killed at 1, 3, and 6 months after treatment.
Results: Ablative lesions were clearly visible at 1 month following therapy
and consistently diminished in size over the 6 months of follow-up. Lesion
size tended to be proportional to dose delivered. Both hepatic and renal l
esions were low in attenuation with frequent rim enhancement that diminishe
d over time. Hepatic lesions frequently showed transient hepatic attenuatio
n differences (THADs). Lesion size appeared independent of proximity to ves
sels.
Conclusion: Following hepatic or renal interstitial radiotherapy, lesions a
re generated that are similar in CT appearance to those produced by other a
blative techniques. The presence of rim or THAD enhancement can be seen ear
ly on as part of the normal tissue-healing response.