Thyroid tissue: US-guided percutaneous interstitial laser ablation-a feasibility study.
OBJECTIVE
To evaluate percutaneous interstitial laser photocoagulation (ILP) as a palliative treatment of recurrent thyroid carcinoma untreatable with surgery or radioiodine administration.


METHODS
By using 18 resected thyroid glands, the volume and histologic pattern of ILP-induced thyroid damage were assessed. In vivo treatment feasibility was evaluated by using a low-energy laser in two volunteers before thyroidectomy for huge autonomously functioning nodules. With ultrasonographic (US) monitoring, a 21-gauge spinal needle was inserted into the thyroid nodules. A 300-microm quartz fiberoptic guide was inserted through the needle lumen, and the fiber tip was placed in direct contact with the tissue. Laser irradiation was performed with a 1.064-nm Nd:YAG laser in surgically resected glands, which were treated with 2, 3, 5, or 7 W.


RESULTS
Tissue ablation was well-defined histologically, and its area was related to laser irradiation parameters (range, 0-26 mm). No correlation was found between US images and the actual extent of laser-induced lesions. Large colloid or fluid collections did not permit regular heat diffusion within the tissue. In vivo low-energy ILP was performed without technical difficulties or complications.


CONCLUSIONS
ILP induces well-defined tissue ablation correlated with energy parameters in thyroid glands devoid of cystic areas. ILP could be a therapeutic tool for highly selected problems in thyroid tumor treatment.
Pacella
C M
CM
Departments of Diagnostic Imaging, and Endocrine, Metabolic, and Digestive Diseases, Regina Apostolorum Hospital, Via San Francesco, 50, 00041 Albano Laziale, Rome, Italy. cmpac@tin.it
Bizzarri
G
G
Guglielmi
R
R
Anelli
V
V
Bianchini
A
A
Crescenzi
A
A
Pacella
S
S
Papini
E
E
D000704:Analysis of Variance; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D017075:Laser Coagulation / Q000379:methods*; D008875:Middle Aged; D012044:Regression Analysis; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D014463:Ultrasonography