Arterial Wall Dosimetry for Non-Hodgkin Lymphoma Patients Treated with Radioimmunotherapy

Journal of Nuclear Medicine

Caroline E. Esaias¹  Richard L. Wahl¹  Eric C. Frey¹  Robert F. Hobbs¹  Heather Jacene¹  Hong Song¹  George Sgouros¹  Bin He¹  Sébastien Baechler¹ 

关键词: oncology;    radiobiology/dosimetry;    radionuclide therapy;    SPECT/CT;    Monte Carlo;    lymphoma;    radioimmunotherapy;    toxicity;   

DOI  :  10.2967/jnumed.109.069575

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Tumors in non-Hodgkin lymphoma (NHL) patients are often proximal to the major blood vessels in the abdomen or neck. In external-beam radiotherapy, these tumors present a challenge because imaging resolution prevents the beam from being targeted to the tumor lesion without also irradiating the artery wall. This problem has led to potentially life-threatening delayed toxicity. Because radioimmunotherapy has resulted in long-term survival of NHL patients, we investigated whether the absorbed dose (AD) to the artery wall in radioimmunotherapy of NHL is of potential concern for delayed toxicity. SPECT resolution is not sufficient to enable dosimetric analysis of anatomic features of the thickness of the aortic wall. Therefore, we present a model of aortic wall toxicity based on data from 4 patients treated with 131I-tositumomab. Methods: Four NHL patients with periaortic tumors were administered pretherapeutic 131I-tositumomab. Abdominal SPECT and whole-body planar images were obtained at 48, 72, and 144 h after tracer administration. Blood-pool activity concentrations were obtained from regions of interest drawn on the heart on the planar images. Tumor and blood activity concentrations, scaled to therapeutic administered activitiesboth standard and myeloablativewere input into a geometry and tracking model (GEANT, version 4) of the aorta. The simulated energy deposited in the arterial walls was collected and fitted, and the AD and biologic effective dose values to the aortic wall and tumors were obtained for standard therapeutic and hypothetical myeloablative administered activities. Results: Arterial wall ADs from standard therapy were lower (0.6–3.7 Gy) than those typical from external-beam therapy, as were the tumor ADs (1.4–10.5 Gy). The ratios of tumor AD to arterial wall AD were greater for radioimmunotherapy by a factor of 1.9–4.0. For myeloablative therapy, artery wall ADs were in general less than those typical for external-beam therapy (9.4–11.4 Gy for 3 of 4 patients) but comparable for 1 patient (32.6 Gy). Conclusion: Blood vessel radiation dose can be estimated using the software package 3D-RD combined with GEANT modeling. The dosimetry analysis suggested that arterial wall toxicity is highly unlikely in standard dose radioimmunotherapy but should be considered a potential concern and limiting factor in myeloablative therapy.

【 授权许可】

Unknown