23–27 Oct 2017
Havana, Cuba
America/Havana timezone

Estimation of volumetric dose distribution delivery deviations from dose planned in $^{131}$I hyperthyroidism treatment: preliminary results

Not scheduled
15m
Biblioteca Pública Rubén Martínez Villena

Biblioteca Pública Rubén Martínez Villena

Biblioteca Pública Rubén Martínez Villena Obispo St. 59, 10200 Old Havana, Havana, Cuba.
Parallel Talk Medical Physics Parallel Session - MP

Speaker

Adlin López Díaz (Nuclear Medicine Department, Hospital “Hermanos Ameijeiras”, Havana, Cuba)

Description

During more than 60 years of Hyperthyroidism radioiodine treatment has been no general agreement on the applied dose or calculus methodology. The EANM Dosimetry Committee recommend in 2013 an “Standard Operational Procedures for Pre-Therapeutic Dosimetry (SOP)” based on the assessment of the individual $^{131}$I uptake and kinetics. To estimate the 3D dose delivery deviations from prescribed dose during patient specific application of this SOP, a computer Matlab application was developed and verified. It was design to execute: radiopharmaceutical curve fitting, cumulated activity calculations, functional thyroid mass estimation, obtain the therapeutic planning activity to warranty the prescribed dose and produce the 3D planning dose map and related dosimetry
parameters. 6 patients with 150-400Gy prescribed dose data planning (average 241,67Gy) were analyzed using the developed application. The developed system was verify successfully using a test image phantom and 6 known pharmacokinetics data. The program fitting results were compared with Microcal (TM) Origin (version 6.0), showing not statistical differences (p <0.01). The tridimensional thyroid volume cumulated activity and dose distributions were heterogeneous. 3D dose distribution showed standard deviations between 20.41-108.3Gy (18.01-27.08% of prescribed dose). The differences between maximum and minimum dose value per voxel/MBq were 74-129%, corresponding to 112Gy and 495Gy respectively for the total dose administrated. According to the result, between 50,2% and 71,4% of patient’s thyroid will be treat with a dose of DP$\pm$20% of planned dose, the rest will be overdose or sub dose.

Conclusions: the 3D treatment planning dose distribution were completely no-homogenous, the significant difference observed should be study in the future more deeply in order to optimized the hyperthyroidism iodine treatment.

Index Terms: optimization, patient’s specific treatment, I-131, Hyperthyroidism

Primary authors

Adlin López Díaz (Nuclear Medicine Department, Hospital “Hermanos Ameijeiras”, Havana, Cuba) Juan Miguel Martín (Nuclear Medicine Department, Hospital “Hermanos Ameijeiras”, Havana, Cuba) Viviana Fernández (Nuclear Medicine Department, Hospital “Hermanos Ameijeiras”, Havana, Cuba) Amalia Pérez (National University of “San Martín”, Buenos Aires, Argentine)

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