Radiation exposure during liver surgery after treatment with (90)Y microspheres, evaluated with computer simulations and dosimeter measurements.
OBJECTIVE
Two patients with liver tumours were planned for a combined treatment, including surgery with preceding injections of β(-) radiation emitting (90)Y microspheres (SIRTEX(®)). The aim of this paper is to present a method of pre-surgical computer simulations of the absorbed dose rate on the surface of tumour tissue, combined with measurements of the actual absorbed dose rate on resected tissue, in order to estimate the absorbed dose to a surgeon's fingers during such surgery procedures.


METHODS
The dose rates from β(-) radiation on the surface of tumour tissue were simulated with the software VARSKIN(®) Mod 2. The activity concentrations in tumours were estimated, based on SPECT/CT distribution studies of (99m)Tc-MAA and confirmed by SPECT/CT bremsstrahlung studies of (90)Y microspheres. The activity distributions were considered as homogeneous within the tumour regions. The absorbed dose rates at different tumour tissue spots were calculated based on measurements with thermo-luminescent dosimeters (TLD) fastened on resected tissue.


RESULTS
The simulations showed a good agreement with the averaged absorbed dose rates based on TLD measurements performed on resected tissue, differing by 13% and 4% respectively. The absorbed dose rates at the measured maximum hotspots were twice as high as the average dose rates for both patients.


CONCLUSIONS
The data is not sufficient in order to draw any general conclusions about dose rates on tumour tissue during similar surgeries, neither about the influence of dose rate heterogeneities nor about average dose rates. However, the agreement between simulations and measurements on these limited data indicate that this approach is a promising method for estimations of the radiation exposure to the surgeons' fingers during this kind of surgery procedure. More data from similar surgeries are necessary in order to validate the method.
Department of Radiation Physics, The Sahlgrenska Academy, University of Gothenburg, SE-413 46 Gothenburg, Sweden. jonas.hogberg@radfys.gu.se
Jonas
J
Högberg
Magnus
M
Rizell
Ragnar
R
Hultborn
Johanna
J
Svensson
Olof
O
Henrikson
Peter
P
Gjertsson
Peter
P
Bernhardt
D000328:Adult; D001650:Bile Duct Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy / Q000601:surgery; D001653:Bile Ducts, Intrahepatic; D018281:Cholangiocarcinoma / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000601:surgery; D003198:Computer Simulation; D005260:Female; D005385:Fingers / Q000528:radiation effects; D013502:General Surgery; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000601:surgery*; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011829:Radiation Dosage; D011874:Radiometry; D011879:Radiotherapy Dosage; D014057:Tomography, X-Ray Computed; D015021:Yttrium Radioisotopes / Q000627:therapeutic use*
D015021:Yttrium Radioisotopes