1. Does a negative 124I and a 131I Scans in Patients with Elevated Thyroglobulin Need a 131I treatment? Updated Results*
Khorjekar GR1, Van Nostrand D1, Oneil J1, Schneider M1, Chennupati SP1, Bandaru VV1, Moreau S1, Burman K2, Wartofsky L2
Divisions of Nuclear Medicine1 and Endocrinology2, Department of Medicine, Washington Hospital Center
* J Nucl Med. 2009; 50 (Supplement 2):1668
Abstract Introduction cont’d Image Acquisition Figure 1 Discussion cont’d
Objectives: To determine the frequency of positive post- well-differentiated thyroid cancer than planar 131I images, This study has several limitations. As a preliminary
Table I
therapy 131I scans in patients with elevated thyroglobulin the frequency of positive post 131I treatment scans in patients study, the sample size is small. Second, the prescribed
Specifications for 131I Acquisition
levels, negative diagnostic 131I scans, AND negative with (1) elevated thyroglobulin blood levels and negative activity of 124I was low. The latter was required because
diagnostic 124I scans . diagnostic 131I planar and 124I PET images has not been of the restrictions of the research protocol and the
Method: Several prospective studies have been performed or evaluated. Radioactive Drug Research Committee limitations of
•Whole body Imaging
are in progress to compare the radiopharmacokinetics of 124I radiation absorbed dose to the volunteer. Again, whether
•ADAC Genesys® dual head whole body speed 4
vs. 131I in patients who (1) had histologically proven well-
differentiated thyroid cancer, (2) were suspected of having
Objective cm/min; 131-I 364 keV, 20% window or or not a higher prescribed activity of 124I will improve
•Siemens E-cam® dual head whole body speed 4 detection of distant metastases sufficiently enough to
metastatic well-differentiated thyroid cancer (e.g. To determine the frequency of positive post-therapy allow 124I PET imaging and/or lesional dosimetry to be
cm/min; 131-I 364 keV, 20% window, and
↑thyroglobulin levels, positive recent FNA, suspicious scans in patients with elevated thyroglobulin levels, negative used to determine if the patient should be treated with 131I
•Planar/Pinhole Imaging
enlarging mass), and (3) were referred for 131I whole body diagnostic 131I scans, AND negative diagnostic 124I PET scans will require further study. With higher prescribed
•Searle® single head with a MIE computer. Planar
dosimetry. Using this database, we retrospectively identified in patients with suspected metastatic well-differentiated activity of 124I stunning will also need to be evaluated.
and pinhole (aperture 6 mm) 1200 sec (20 min);
those patients who had 1) positive thyroglobulin, (2) a thyroid cancer. 131-I 364 keV, 20% window
negative diagnostic 131I scan, (3) a negative diagnostic 124I
scan, (4) therapy with 131I , and (5) a post-therapy scan. For
Method Conclusions
each image, one reader (dvn) categorized every focus of 131I
and 124I radioiodine uptake as 1=definite physiological uptake- Table II Coronal Preliminary data indicates that (1) 131I post-treatment
Coronal
artifact, 2 = most likely physiological uptake-artifact, 3 = A prospective study was performed at Washington Specifications for 124I Acquisition and Processing scans are frequently positive in patients who have
indeterminate, 4 = residual thyroid tissue/metastases (mets) in Hospital Center to compare the radiopharmacokinetics of elevated thyroglobulins, negative diagnostic 131I planar
124I vs. 131I in patients (1) who had histologically proven well-
the neck/bed, 5 = most likely mets, or 6 = definite mets. •GE Advance Nxi® scans, AND negative 124I PET scans. (2) A negative 124I
Categories 4, 5 or 6 were considered positive. Whenever differentiated thyroid cancer, (2) were suspected of having •Emission scans 5 min/bed position. PET scan in a patient with an elevated thyroglobulin
possible, foci were correlated with other diagnostic studies.. metastatic well-differentiated thyroid cancer (e.g. elevated •Transmission scans 2.5 min/bed position. Figure 1 demonstrates an example of negative pre-therapy 131I planar scan and blood level will have a low predictive value of a negative
negative active 124I PET scan with a positive post-therapy 131I scan. On the post-
Results: Of the total of 40 patients, 12 patients had positive thyroglobulins levels, positive recent FNA, suspicious •Processing: reconstruction OSEM (4.3mm isotropic therapy 131I anterior images, diffuse (black arrows), as well as, focal uptake (red post 131I treatment scan and should not be used to
thyroglobulin, negative diagnostic 131I, negative 124I scans, enlarging mass), and (3) were referred for 131I whole body pixels) with segmented attenuation correction, or arrows) are present in both lung fields in both the anterior and posterior view. exclude the option of a 131I treatment.
therapy with 131I, and a post-therapy scan. Ten of these 12 dosimetry. A second and third prospective study evaluating •Philips Gemini 64TF®
patients had positive foci on 131I post-therapy scan. the radiopharmacokinetics of 124I vs. 131I is in progress using •Emission scans 4 min/bed position.
Conclusion: Preliminary data indicates that: (1) 131I post- the same criteria as above except patients are being prepared •14 to 16 bed positions. diagnostic 124I PET scan of the thorax was visually positive for References
therapy scans are frequently positive in patients with positive only with thyroid hormone withdrawal in the second study •CT attenuation scans, 120 kV, 30 mAs. diffuse pulmonary metastases (DPM) when the post 131I 1. Freudenberg LS, Jentzen W, Marlow RJ, Koska WW, Luster M, Bockisch A. 124-iodine
thyroglobulin, negative diagnostic 131I, AND negative 124I and only recombinant human TSH (Thyrogen®) in the third •Processing: reconstruction OS-TF with SAC using the treatment scan was positive and the computer tomography scan positron emission tomography/computed tomography dosimetry in pediatric patients
with differentiated thyroid cancer. Exp Clin Endocrinol Diabetes. 2007;115:690-693.
scans, and (2) a negative 124I scan in patients with a positive study. CT data. was negative for DPM. Of seven patients only one patient was 2. Freudenberg LS, Antoch G, Jentzen W, Pink R, Knust J, Gorges R, Muller SP, Bockisch A,
Debatin JF, Brandau W. Value of 124-I PET/CT in staging of patients with differentiated
thyroglobulin level will have a low predictive value of a From these three databases, we retrospectively positive in the thorax on 124I PET scan. In this study, the thyroid cancer. Euro Rad 2004;14:2092-2098.
3. Van Nostrand D, Moreau S, Atkins FB, Shin Y, Burman KD, Wartofsky L. I-124 versus I-
negative post 131I therapy scan and should not be used to identified all patients who had 1) elevated thyroglobulins, (2) patients received 0.65 mCi (24+ 2 MBq) of 124I . 131 in the identification of suspected residual thyroid tissue or metastasis in patients
exclude the option of a 131I therapy. a negative diagnostic 131I planar scan, (3) a negative Results The importance of Freudenberg et al.’s report [12] and the
with well-differentiated thyroid cancer (well-differentiated thyroid cancer). J Nucl Med
2008;49 (Suppl):356P.
4. Phan HTT, Jager PL, Paans AMJ, Plukker JTM, Sturkenboom MGG, Sluiter WJ,
diagnostic 124I PET scan, (4) treatment with 131I, and (5) a present preliminary report are two fold. First, a negative 124I Wolffeenbuttel BHR, Dierckx RAJO, Links TP. The diagnostic value of 124-I PET in
Introduction post treatment scan. For each image, one reader (dvn)
categorized every focus of 131I and 124I radioiodine uptake as
Of a total of 40 patients from the three studies, 12
patients had elevated thyroglobulins, negative 131I planar scan,
PET scan at the dosages administered should not exclude the
patients with differentiated thyroid cancer. Eur J Nucl Med Mol Imaging 2008;35:958-965.
5. Nemec J, Rohling S, Zamarazil V, Pohunkova D. Comparison of the distribution of
diagnostic and thyroablative 1-131 in the evaluation of differentiated thyroid cancers. J
consideration of an 131I treatment in patients who have elevated Nucl Med 1997;38 20:92-97.
Imaging of thyroid cancer with 124I and a PET 1 = definite physiological uptake/ artifact, 2 = most likely negative 124I PET scan, treatment with 131I, and a post- 6. Fatourechi V, Hay I, Mullan BP, et al. Are post therapy radioiodine scans informative and
thyroglobulin blood levels. Second and unfortunately, these do they influence subsequent therapy of patients with differentiated thyroid cancer?
scanner has been demonstrated by several authors to be physiological uptake/artifact, 3 = indeterminate, 4 = residual treatment scan. Ten of these 12 patients had positive foci on 131I Thyroid 2000;10:573-577.
reports indicate that lesional dosimetry with 124I PET scanning 7. Balachandran S, Sayle BA. Value of thyroid carcinoma imaging after therapeutic doses
superior to 131I planar imaging [1-4]. This superiority is thyroid tissue/metastases in the neck/bed, 5 = most likely post-treatment scan. An example is shown in Figure 1. of radioiodine. Clin Nucl Med 1981;6:162-167.
could not have been performed to potentially determine whether 8. Sherman S, Tielens ET, Sostre S, et al. Clinical utility of post treatment radioiodine scans
due to a combination of factors including improved spatial metastasis, or 6 = definite metastasis. Category of 4, 5, or 6 or not an 131I treatment may have a therapeutic benefit. To in the management of patients with thyroid carcinoma. J Clin Endocrinol Metab
1994;78:629-634.
resolution, improved contrast resolution, tomographic
imaging, and the ability to fuse the tomographic images
were considered positive. When possible,
correlated with other diagnostic studies.
foci were Discussion determine whether or not non-visualization of DPM and/or any 9. Spies WG, Wojtowicz CH, Spies SM, et al. Value of post-therapy whole-body 1-131
imaging in the evaluation of patients with thyroid carcinoma having undergone high-
other distant metastases on an 124I PET scan may indicate that dose 1-131 therapy. Clin Nucl Med 1989;14:793-800.
with CT and/or MR for better anatomical localization [1- an 131I treatment would be ineffective will require a study of
10. Pineda JD, Lee T, Ain K, et al. Iodine-13I therapy for thyroid cancer patients with elevated
The 131I planar images and 124I PET images were Previously, multiple authors [5-11] have reported that thyroglobulin and negative ative diagnostic scan. J Clin Endocrinol Meta 1995;80:1488-
4]. patient outcomes after 131I treatment. However, because of many 1492.
performed as noted in Table I and II, respectively. The post 131I treatment scans may be positive in as many as 66% of 11. Rosario PWSD, Barroso AL, Rezende LL, et al. Post 1-131 therapy scanning in patients
with thyroid carcinoma metastases; an unnecessary cost or a relevant contribution?
Although 124I PET imaging can detect more foci of prescribed activity was 1-2 mCi (37-74 MBq) and 1.7 mCi patients who have positive thyroglobulin blood levels and a factors not the least of which would be the various prescribed Clin Nuc Med 2004;29:795-798.
residual thyroid tissue and/or metastases secondary to (63 MBq) for 131I and 124I respectively. negative diagnostic 131I whole body scan. For 124I PET scans, activities of 124I for the diagnostic 124I PET scans, an outcome 12. Freudenberg LS, Jentzen W, Muller SP, Bockisch A. Disseminated iodine-avid lung
metastases in differentiated thyroid cancer: a challenge to 124-I PET. Eur J Nucl Med
Freudenberg et al. [12] evaluated the frequency that of a study would be difficult to perform. Mol Imaging 2008;35:502-508.