Research ArticleClinical Investigations

Assessment of Simplified Blood Dose Protocols for the Estimation of the Maximum Tolerable Activity in Thyroid Cancer Patients Undergoing Radioiodine Therapy Using 124I

Walter Jentzen, Andreas Bockisch and Marcus Ruhlmann
Journal of Nuclear Medicine June 2015, 56 (6) 832-838; DOI: https://doi.org/10.2967/jnumed.114.153031

Article Figures & Data

Figures

  • FIGURE 1.
    FIGURE 1.

    Schematic representation of uptake curves of reference protocol (A) and examples of simplified protocols (B–D). Different phases are indicated by vertical dotted lines. Numbers adjacent to lines represent monoexponential function. Dashed lines indicate extrapolated values. No numbers on uptake axes are shown.

  • FIGURE 2.
    FIGURE 2.

    Relationship between whole-body residence time vs. blood residence time for patient group before (A) and after treatment (B). Outliers (B) are marked with arrows. Dashed lines indicate reduced major axis regression lines.

  • FIGURE 3.
    FIGURE 3.

    Box plot representation of distribution of percentage MTA deviation in patient group before (A) and after treatment (B) for simplified protocols and SOP protocol. Horizontal dashed lines indicate percentage deviation range of ±20%. Inserts show enlarged view of MTA deviations of equivalent protocols.

  • FIGURE 4.
    FIGURE 4.

    Lin’s concordance correlation plots of equivalent protocols (A, B) found in this study and of SOP protocol (C) for patient group before treatment. Lines of identity (45° line) and reduced major axis regression lines are shown by solid and dashed lines, respectively.

  • FIGURE 5.
    FIGURE 5.

    Lin’s concordance correlation plots of equivalent protocols (A, B) found in this study and of SOP protocol (C) for patient group after treatment. Plots of 2 other equivalent protocols, C(24,96) and C(48,96), are not shown. Lines of identity (45° line) and reduced major axis regression lines are shown by solid and dashed lines, respectively.

Tables

  • TABLE 1

    Demographic and Clinical Characteristics

    CharacteristicGroup before treatmentGroup after treatment
    No. of patients108103
    Age (y)51 (54) ± 19 (12–83)55 (59) ± 18 (17–84)
    Sex
     Male4343
     Female6560
    Weight (kg)80 (75) ± 19 (46–144)81 (80) ± 18 (44–129)
    Height (cm)169 (168) ± 9 (148–192)169 (169) ± 9 (150–195)
    Blood volume (L)4.61 (4.25) ± 0.90 (3.14–7.40)4.65 (4.49) ± 0.86 (3.21–6.85)
    TNM*
     Tx/T1/T2/T3/T44/10/15/13/667/7/26/17/46
     N0/N146/6239/64
     M0/M178/3061/42
    Histology (papillary/follicular)83/2559/44
    Diffuse pulmonary metastases178
    TSH stimulation (endogenous/exogenous)87/2154/49
    TSH level (mIU/L)85 (77) ± 45 (25–259)106 (104) ± 50 (25–240)
    124I activity (MBq)23 (22) ± 5 (18–50)26 (22) ± 8 (18–49)

    • ↵* TNM, initial tumor staging according to fifth UICC classification.

    • Statistics are provided in the following form: mean (median) ± SD (minimum to maximum).

  • TABLE 2

    Dosimetry Characteristics Derived from Using Reference Protocol

    CharacteristicGroup before treatmentGroup after treatment
    Reference MTA (GBq)21 (21) ± 8 (6–48)25 (24) ± 9 (6–49)
    Bone marrow/lung*95/13103/0
    Whole-body residence time (h)31 (27) ± 15 (13–81)22 (20) ± 9 (11–60)
    Blood residence time (h)3.2 (2.7) ± 1.4 (1.5–9.9)2.9 (2.6) ± 1.3 (1.2–9.9)
    Residence time ratio (τBS/τWC)0.11 (0.11) ± 0.03 (0.03–0.23)0.13 (0.13) ± 0.02 (0.05–0.19)
    Blood uptake at 2 h (%)13.9 (13.9) ± 2.6 (7.2–22.1)14.2 (14.1) ± 2.7 (7.2–22.4)
    Blood dose (Gy/GBq)0.11 (0.09) ± 0.05 (0.04–0.34)0.09 (0.08) ± 0.04 (0.04–0.34)
    Whole-body retention at 48 h (%)16 (13) ± 10 (2–57)10 (8) ± 8 (1–41)
    Contribution of β dose† (%)70 (71) ± 7.0 (43–83)74 (74) ± 4.1 (54–83)

    • ↵* Number of patients with MTAs limited by possible bone marrow or lung toxicity.

    • ↵† Percentage of β-particle dose to total blood dose.

    • Statistics are provided in the following form: mean (median) ± SD (minimum to maximum).

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