124I PET-based 3D-RD dosimetry for a pediatric thyroid cancer patient: real-time treatment planning and methodologic comparison.
Patient-specific 3-dimensional radiobiologic dosimetry (3D-RD) was used for (131)I treatment planning for an 11-y-old girl with differentiated papillary thyroid cancer, heavy lung involvement, and cerebral metastases. (124)I PET was used for pharmacokinetics. Calculation of the recommended administered activity, based on lung toxicity constraints, was performed in real time (i.e., during the data-acquisition interval). The results were available to the physician in time to influence treatment; these estimates were compared with conventional dosimetry methodologies. In subsequent, retrospective analyses, the 3D-RD calculations were expanded to include additional tumor dose estimates, and the conventional methodologies were reexamined to reveal the causes of the differences observed. A higher recommended administered activity than by an S-value-based method with a favorable clinical outcome was obtained. This approach permitted more aggressive treatment while adhering to patient-specific lung toxicity constraints. A retrospective analysis of the conventional methodologies with appropriate corrections yielded absorbed dose estimates consistent with 3D-RD.
Hobbs
Robert F
RF
Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21231, USA.
Wahl
Richard L
RL
Lodge
Martin A
MA
Javadi
Mehrbod S
MS
Cho
Steve Y
SY
Chien
David T
DT
Ewertz
Marge E
ME
Esaias
Caroline E
CE
Ladenson
Paul W
PW
Sgouros
George
G
D002648:Child; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D049268:Positron-Emission Tomography; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D013997:Time Factors
D007457:Iodine Radioisotopes