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Potential role of a new hand-held miniature gamma camera in performing minimally invasive parathyroidectomy

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Sestamibi scans have increased the use of minimally invasive parathyroidectomy (MIP) to treat primary hyperparathyroidism (PHPT) when caused by a parathyroid single adenoma. The greatest concern for surgeons remains the proper identification of pathological glands in a limited surgical field. We have studied the usefulness of a new hand-held miniature gamma camera (MGC) when used intraoperatively to locate parathyroid adenomas. To our knowledge this is the first report published on this subject in the scientific literature. Five patients with PHPT secondary to a single adenoma, positively diagnosed by preoperative sestamibi scans, underwent a MIP. A gamma probe for radioguided surgery and the new hand-held MGC were used consecutively to locate the pathological glands. This new MGC has a module composed of a high-resolution interchangeable collimator and a CsI(Na) scintillating crystal. It has dimensions of around 15 cmx8 cmx9 cm and weighs 1 kg. The intraoperative assay of PTH (ioPTH) was used to confirm the complete resection of pathological tissue. All cases were operated on successfully by a MIP. The ioPTH confirmed the excision of all pathological tissues. The MGC proved its usefulness in all patients, even in a difficult case in which the first attempt with the gamma probe failed. In all cases it offered real-time accurate intraoperative images. The hand-held MGC is a useful instrument in MIP for PHPT. It may be used to complement the standard tools used to date, or may even replace them, at least in selected cases of single adenomas.
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Short communication
Potential role of a new hand-held miniature gamma camera
in performing minimally invasive parathyroidectomy
Joaquin Ortega
1
, Jose Ferrer-Rebolleda
3
, Norberto Cassinello
2
, Salvador Lledo
1
1
Department of Surgery, University of Valencia, Clinic University Hospital, Av. Blasco Ibanez 17, 46010 Valencia, Spain
2
Unit of Endocrinologic and Bariatric Surgery, Clinic University Hospital, Valencia, Spain
3
Department of Nuclear Medicine, Clinic University Hospital, Valencia, Spain
Received: 18 April 2006 / Accepted: 25 June 2006 / Published online: 11 October 2006
© Springer-Verlag 2006
Abstract. Purpose: Sestamibi scans have increased the
use of minimally invasive parathyroidectomy (MIP) to
treat primary hyperparathyroidism (PHPT) when caused
by a parathyroid single adenoma. The greatest concern for
surgeons remains the proper identification of pathological
glands in a limited surgical field. We have studied the
usefulness of a new hand-held miniature gamma camera
(MGC) when used intraoperatively to locate parathyroid
adenomas. To our knowledge this is the first report
published on this subject in the scientific literature.
Methods: Five patients with PHPT secondary to a single
adenoma, positively diagnosed by preoperative sestamibi
scans, underwent a MIP. A gamma probe for radioguided
surgery and the new hand-held MGC were used
consecutively to locate the pathological glands. This new
MGC has a module composed of a high-resolution
interchangeable collimator and a CsI(Na) scintillating
crystal. It has dimensions of around 15 cm×8 cm×9 cm
and weighs 1 kg. The intraoperative assay of PTH (ioPTH)
was used to confirm the complete resection of pathological
tissue.
Results: All cases were operated on successfully by a MIP.
The ioPTH confirmed the excision of all pathological
tissues. The MGC proved its usefulness in all patients,
even in a difficult case in which the first attempt with the
gamma probe failed. In all cases it offered real-time
accurate intraoperative images.
Conclusion: The hand-held MGC is a useful instrument in
MIP for PHPT. It may be used to complement the standard
tools used to date, or may even replace them, at least in
selected cases of single adenomas.
Keywords: Primary hyperparathyroidism Parathyroid
adenoma Minimally invasive surgical procedures
Intraoperative procedures Miniature gamma camera
Eur J Nucl Med Mol Imaging (2007) 34:165169
DOI 10.1007/s00259-006-0239-7
Introduction
The introduction of
99m
Tc-sestamibi scintigraphy to
identify and locate preoperatively the parathyroid adeno-
mas in primary hyperparathyroidism (PHPT) opened the
possibility of performing single gland parathyroidectomies
via minimal access, with outcome results similar to those
achieved using bilateral neck exploration [1].
We have used the new hand-held miniature gamma
camera (MGC) Sentinella 102 (GEM-Imaging SL, Spain)
within the surgical field in order to verify its possible value
in the detection of parathyroid adenomas when using
minimally invasive access for parathyroidectomy. The use
of portable hand-held gamma cameras has been reported in
other medical fields, especially in surgery and pre-surgery
sentinel node techniques [24] and thyroid scintigraphy
[5]. To our knowledge, this is the first report on use of a
hand-held MGC to intraoperatively locate pathological
parathyroid glands.
Materials and methods
We included five patients with clinical and laboratory findings of
PHPT, with positive
99m
Tc-sestamibi scintigraphy for a single
adenoma. Calcium, phosphorus and parathyroid hormone (PTH)
were registered pre-operatively and 3 months postoperatively. All the
patients included in this study had previously given their informed
consent, and the entire research project was authorised by the
Committee for Ethical Research at the hospital.
A -planar conventional parathyroid scintigraphy (740 MBq, i.e.
20 mCi,
99m
Tc-sestamibi dual-phase scintigraphy protocol [6, 7]) had
An Editorial commentary on this paper is available at
http://dx.doi.org/10.1007/s00259-006-0250-z
Joaquin Ortega ())
Unit of Endocrinologic and Bariatric Surgery,
Clinic University Hospital,
Valencia, Spain
e-mail: joaquin.ortega@uv.es
Tel.: +34-963-864169, Fax: +34-963-864805
European Journal of Nuclear Medicine and Molecular Imaging Vol. 34, No. 2, February 2007
previously been implemented in all patients using two large field of
view gamma cameras (GE Genie single-head and Elscint Helix dual-
head gamma cameras), both equipped with parallel-hole, low-energy,
high-resolution collimators. Images of the head and mediastinum
were recorded in a 128×128 matrix, 20 min and 2 h post injection. In
four patients a subtraction image was obtained 20 min after the
injection of a standard dose of
99m
Tc-pertechnetate [185 MBq
(5 mCi)] in order to clarify the origin (thyroid vs parathyroid) of
abnormal
99m
Tc-sestamibi uptake. In order to improve the diagnosis,
single-photon emission computed tomography (SPECT) images
were acquired in one patient using the dual-head gamma camera and
the following parameters: circular orbit, 120 steps over 360°, 25 s per
step and a 64×64 matrix.
On the day of the surgery, 111185 MBq (35mCi)of
99m
Tc-
sestamibi (Cardiolite, Bristol Myers Squibb Pharma Belgium Sprl) was
injected in the operating room 10 min before surgery. Next, three to
eight images, each of about 2030 s, were acquired before and during
the surgery with the Sentinella 102 equipped with a pin-hole 4-mm
collimator and using a 300×300 matrix. Before the surgical incision,
planar imaging was performed, placing the collimator at a distance of
15 cm. This permitted visualisation, at a low resolution, of the cervical
and superior thoracic field, from the salivary glands to the heart.
The MIP was performed through a 2-cm cervical incision, made
over the point of maximal isotope uptake as seen on preoperative
imaging. Surgical telescopes 2.5× (Designs for Vision, USA) were
used by the surgeon to improve the surgical field view.
Intraoperative location of the pathological gland was achieved by
the use of both the gamma probe Navigator GPS (RMD Systems
LLC, USA) and the hand-held MGC Sentinella 102. These devices
were also used to verify the absence of positive radioactivity after
resection of pathological gland. Complete removal of pathological
tissue was confirmed by an intraoperative quick PTH assay (ioPTH)
(PTH intact test, CV intra-assay 1.1%, CV inter-assay 2.8%, Cobas,
Roche Diagnostics GmbH, Germany) before and 15 min after gland
resection. Frozen sections of all resected glands were performed.
The new Sentinella 102 hand-held MGC (Fig. 1) has a head
module composed of a high-resolution interchangeable lead colli-
mator (pin-hole apertures of 1.0, 2.5 and 4.0 mm), a continuous CsI
(Na) scintillating crystal and a flat panel position-sensitive photo-
multiplier tube. This gamma camera has dimensions of around
15 cm×8 cm×9 cm, weighs 1 kg and just requires a single 3-m wire
connection to a laptop computer for proper operation. The real-time
acquisition is controlled by a user software that runs under Windows
XP. It is capable of showing high-quality planar gamma images of the
body, which can be better obtained with the camera coupled to an
articulated arm for good stability. This MGC is characterised by an
intrinsic spatial resolution of 1.6 mm. Due to the use of a pin-hole
collimator, it has a variable field of view (FOV) according to the
aperture and to the distance from the body to the pin-hole, achieving
a 20-cm FOV while maintaining reasonable resolution. The spatial
resolution at a distance of 100 mm is 10 mm (pin-hole 2.5) and
18 mm (pin-hole 4). This small gamma camera offers a high
sensitivity (2002,000 cpm/μCi 10 mm away, 60160 cpm/μCi
100 mm away), which allows quick imaging acquisition (less than
20 s). Its ability to localise small hot radiation regions is improved by
means of accessory tools for reference position establishment
between body and gamma image. We tested one of these tools, the
so-called LASER Positioning System (LPS). It provides a LASER
cross pointing at the FOV central point on the body, with a virtual
cross mark at the same position in the gamma image.
Results
In all cases, all tests were positive. The five patients had
PHPT owing to a single adenoma, and the proper location
was correctly marked by preoperative sestamibi scans. We
intraoperatively used the gamma camera to obtain a
dynamic cervical scan every 10 min, and we could observe
progressive wash-out of isotope from the thyroid and
background, facilitating identification of the adenoma. In
all cases, the MGC provided the same information as the
preoperative imaging, and the initial images always
showed a hot spot for the parathyroid adenomas. The
gamma probe helped us to locate the glands and findings
were always concordant with gamma camera scans.
The gamma camera was always able to locate surgically
the adenomas at a good resolution, the head of the gamma
camera being placed 510 cm from the thyroid (Fig. 2).
After the excision, a scan of the gland ex vivo was
performed (Fig. 3), and thereafter an image of the surgical
field was taken in order to confirm absence of the previous
hot spot. In one of the cases, with a preoperative diagnosis
of adenoma in the right inferior parathyroid gland, a normal
gland was found orthotopically although there was a hot
spot and the gamma probe counts were still elevated. The
resection of two small tumours did not alter this condition,
with persistence of a hot spot on dynamic scintigraphy, and
the frozen sections revealed two enlarged adenopathies. A
lateral view of the surgical field with the gamma camera
identified a posterior location of the hot spot (Fig. 2), and
an adenoma was then found in the retro-oesophageal space,
corresponding to a migrated superior parathyroid gland. In
this case the intervention took slightly longer (100 min),
but in the rest of cases, location was quick and easy (always
less than 60 min), and all tools showed their usefulness. In
all cases the results of ioPTH confirmed resection of the
Fig. 1. Sentinella 102 gamma camera, with its connection to a laptop
166
European Journal of Nuclear Medicine and Molecular Imaging Vol. 34, No. 2, February 2007
pathological gland, with an average decrease of 76.9% in
the hormone level.
The average size of the parathyroid adenomas was
2.3 cm×1.3 cm. The postoperative values of calcium,
phosphorus and PTH were normalised in all cases.
Discussion
Most authors agree that
99m
Tc-sestamibi scintigraphy is the
most powerful preoperative diagnostic tool in PHPT, and it
has undoubtedly been responsible for the changes in
therapeutic strategy. The addition of various techniques
has increased the accuracy of
99m
Tc-sestamibi scintigraphy,
the most frequently reported being the double-tracer
subtraction technique with
99m
Tc-pertechnetate and SPECT
[810].
Cases of PHPT with a single hot spot on
99m
Tc-
sestamibi scintigraphy and without thyroid pathology are
considered suitable for MIP. The success of radio-guided
surgery and/or ioPTH in locating the glands and confirm-
ing the total excision of pathological tissue has been cited
to justify MIP, and, when used together, these techniques
achieve a high accuracy in selected cases [11]. Never-
theless, it is well established that sestamibi scans fail to
provide information in inappropriate cases and that even
ioPTH, the test reported to be the most accurate [12],
sometimes fails or presents limitations [3, 13].
In our cases we used various diagnostic and therapeutic
tools in an attempt to ascertain whether all the results were
concordant with the findings of planar imaging using the
new MGC. In all patients, the tests were positive for a
single adenoma and these cases were scheduled for MIP.
Immediately prior to surgery, when the patient was in
the operating room, a low dose of
99m
Tc-sestamibi, 111
185 MBq (35 mCi), was injected intravenously. We
decided to perform the initial diagnostic scan and surgery
on different days, similar to Rubello et al. [14], using low
doses of isotope, in order to reduce the threat of radioac-
tivity and to shorten the waiting time after injection. This
allowed rapid wash-out of isotope from the thyroid and
background, and provided better identification of a single
spot of radioactivity. A gamma probe was used to locate the
adenomas and its efficacy was compared with that of the
MGC. In our opinion, use of the gamma probe can be
avoided if an MGC is available: the morphological
expression of anatomical structures on planar images and
the possibility of obtaining lateral views provide more
information than is acquired using a gamma probe, with its
aspecific counts and sounds. Moreover, incomplete wash-
out of the isotope from the thyroid may lead to misleading
records from the gamma probe. In addition, we have
confirmed the feasibility of using the MGC after giving low
doses of isotope, as first indicated by Casara et al. [15, 16].
The concordance between the preoperative conventional
sestamibi scans and the immediate presurgical MGC
images leads us to think that, after more experience has
been acquired, dynamic imaging could even replace the
previous diagnostic scans, at least in order to decide upon
the type of intervention. The initial low-resolution imaging,
performed at a distance of 15 cm, permitted us to identify
the adenomatous gland and to rule out the presence of
ectopic tissue. Next, scans were performed at a shorter
distance to increase resolution, permitting more accurate
anatomical mapping. A quick ioPTH assay was performed
in all patients before surgery and 1015 min post adenoma
Fig. 2.
99m
Tc-sestamibi scintigraphy with the Sentinella 102. Lateral
view of the cervical field shows anterior thyroid activity and a
posterior parathyroid adenoma
Fig. 3.
99m
Tc-sestamibi scintigraphy with the Sentinella 102.
Parathyroid adenoma after its removal
167
European Journal of Nuclear Medicine and Molecular Imaging Vol. 34, No. 2, February 2007
resection. The aim of evaluating the completeness of
removal of all hyperfunctioning parathyroid tissue was
achieved in all cases using the MGC, which allowed us to
see the complete disappearance of hot spots.
We have found just a single reference to the use of a
gamma camera in the operating room for hyperparathy-
roidism, even though it was not hand-held and portable.
This was a case report by Kitagawa et al. [17], who
presented the use of a solid-state multi-crystal gamma
camera for
99m
Tc-sestamibi scintigraphy preoperatively
and intraoperatively, 1 h after injection of a large dose of
600 MBq (16.2 mCi) of isotope.
We have not found any mention in the scientific
literature of the use of a portable hand-held MGC for
intraoperative techniques related to the parathyroid.
Although there are references on the use of portable
hand-held gamma cameras for sentinel node detection
[2 4], it seems that surgeons are not completely sure about
introducing small gamma cameras into the operating room.
Imaging is perhaps not worthwhile if it sacrifices a lot of
operating time and if quick and precise node localisation is
not assured. These problems are significantly reduced by
the high sensitivity of the Sentinella 102 and by using the
LPS. The acquisition of valid images on the screen was
very fast, and in some cases 20 s was enough to obtain a
positive scan. Furthermore, we could verify a very good
function with small amounts of isotope, confirming rapid
wash-out of the isotope, as suggested by Rubellos group
[9, 1416] for radio-guided surgery. Moreover, radiation
exposure of the surgeon and his team was much reduced.
In our opinion this new device is useful for localisation
of pathological glands in cases of PHPT. It is easy to
manage and allows different views to be taken, even lateral
ones, permitting viewing of the entire surgical field or even
of other parts of the body. It can substitute for gamma
probes, whose determinations can be misleading in difficult
cases, as occurred with one of our cases. On the other hand,
it proved effective in identifying all the pathological tissue
and in confirming its complete excision. Goldstein et al.
[18] reported a very good cure rate of 98% in patients
undergoing minimally invasive radioguided surgery with-
out the intraoperative use of PTH measurement. This
indicates that even without ioPTH, our method would be
more accurate by virtue of the morphological information
provided.
In conclusion, for the kind of case reported by us (PHPT
due to a single adenoma, with positive uptake for sestamibi),
our preliminary results indicate the proposed procedure to be
very cost-effective. MIP was effective with the help of only
the intraoperative MGC, after a very low dose of preoper-
ative
99m
Tc-sestamibi, which permitted localisation and
confirmation of complete removal of pathological tissue. In
our opinion, the MGC could completely replace the
intraoperative use of gamma probes. It would even be
possible to replace the preoperative conventional sestamibi
scans and the intraoperative determinations of PTH,
although more experience is needed to confirm this exciting
and cost-effective possibility.
Acknowledgement. This work was partially funded by a Grant for the
Development of Research Programmes in Matters of Health (S.P.-
0037/2005) from the Conselleria de Sanitat de la Generalitat
Valenciana.
References
1. Sackett WR, Barraclough B, Reeve TS, Delbridge LW.
Worldwide trends in the surgical treatment of primary hyper-
parathyroidism in the era of minimally invasive parathyroidec-
tomy. Arch Surg 2002;137:10559.
2. Fujii H, Kitagawa Y, Kitajima M, Kubo A. Sentinel nodes of
malignancies originating in the alimentary tract. Ann Nucl Med
2004;18:112.
3. Fernandez MM, Benlloch JM, Cerda J, Escat B, Gimenez EN,
Gimenez M, et al. A flat-panel-based mini gamma camera for
lymph nodes studies. Nucl Instrum Methods Phys Res A
2004;527:926.
4. Pitre S, Menard L, Ricard M, Solal M, Garbay JR, Charon Y. A
hand-held imaging probe for radio-guided surgery: physical
performance and preliminary clinical experience. Eur J Nucl
Med Mol Imaging 2003;30:33943.
5. Sanchez F, Benlloch JM, Escat B, Pavon N, Porras E, Kadi-
Hanifi D, et al. Design and tests of a portable mini gamma
camera. Med. Phys 2004;31:138497.
6. Serena A, Campos LM. Procedimientos en Medicina Nuclear
Clinica. Pontevedra (Spain): Caixa Nova & Nycomed Amersham;
2000.
7. Greenspan BS, Brown ML, Dillehay GL, McBiles M, Sandler
MP, Seabold JE, et al. The Society of Nuclear Medicine
procedure guideline for parathyroid scintigraphy. Version 3.0,
Reston, Va. SNM Ed. 2004.
8. Mariani G, Gulec SA, Rubello D, Boni G, Puccini M, Pelizzo
MR, et al. Preoperative localization and radioguided parathy-
roid surgery. J Nucl Med 2003;44:144358.
9. Rubello D, Giannini S, De Carlo E, Mariani G, Muzzio PC,
Rampin L, et al. Minimally invasive
99m
Tc-sestamibi radio-
guided surgery of parathyroid adenomas. Panminerva Med
2005;47:99107.
10. Lorberboym M, Ezri T, Schachter PP. Preoperative technetium
99m
Tc-sestamibi SPECT imaging in the management of primary
hyperparathyroidism in patients with concomitant multinodular
goiter. Arch Surg 2005;140:65660.
11. Chen H, Mack E, Starling JR. A comprehensive evaluation of
perioperative adjuncts during minimally invasive parathy-
roidectomy: which is most reliable? Ann Surg 2005;242:37580.
12. Chen H, Pruhs Z, Starling JR, Mack E. Intraoperative
parathyroid hormone testing improves cure rates in patients
undergoing minimally invasive parathyroidectomy. Surgery
2005;138:5837.
13.SuggSL,KrzywdaEA,DemeureMJ,WilsonSD.Detectionof
multiple gland primary hyperparathyroidism in the era of minimally
invasive parathyroidectomy. Surgery 2004;136:13039.
14. Rubello D, Piotto A, Casara D, Muzzio PC, Shapiro B, Pelizzo
MR. Role of gamma probes in performing minimally invasive
parathyroidectomy in patients with primary hyperparathy-
roidism: optimization of preoperative and intraoperative
procedures. Eur J Endocrinol 2003;149:715.
15. Casara D, Rubello D, Piotto A, Pelizzo MR.
99m
Tc-MIBI radio-
guided minimally invasive parathyroid surgery planned on the
basis of a preoperative combined
99m
Tc-pertechnetate/
99m
Tc-
MIBI and ultrasound imaging protocol. Eur J Nucl Med Mol
Imaging 2000;27:13004.
168
European Journal of Nuclear Medicine and Molecular Imaging Vol. 34, No. 2, February 2007
16. Casara D, Rubello D, Pelizzo MR, Shapiro B. Clinical role of
99m
TcO
4
/MIBI scan, ultrasound and intra-operative gamma
probe in the performance of unilateral and minimally invasive
surgery in primary hyperparathyroidism. Eur J Nucl Med Mol
Imaging 2001;28:13519.
17. Kitagawa W, Shimizu K, Akasu H. Radioguided parathy-
roidectomy for primary hyperparathyroidism using the solid-
state, multi-crystal gamma camera. Med Sci Monit 2003;9:
CS5962.
18. Goldstein RE, Billheimer D, Martin WH, Richards K. Sestamibi
scanning and minimally invasive radioguided parathyroidectomy
without intraoperative parathyroid hormone measurement. Ann
Surg 2003;237:72230.
169
European Journal of Nuclear Medicine and Molecular Imaging Vol. 34, No. 2, February 2007
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Biophotonic imaging has revolutionized the operation room by providing surgeons intraoperative image-guidance to diagnose tumors more efficiently and to resect tumors with real-time image navigation. Among many medical imaging modalities, near-infrared (NIR) light is ideal for image-guided surgery because it penetrates relatively deeply into living tissue, while nuclear imaging provides quantitative and unlimited depth information. It is therefore ideal to develop an integrated imaging system by combining NIR fluorescence and gamma-positron imaging to provide surgeons with highly sensitive and quantitative detection of diseases, such as cancer, in real-time without changing the look of the surgical field. The focus of this review is to provide recent progress in intraoperative biophotonic imaging systems, NIR fluorescence imaging and intraoperative nuclear imaging devices, and their future perspectives for image-guided interventions.
... At the time of writing there were no similar studies being carried out by other hybrid SFOV gamma cameras. Based on the literature search, most of the clinical applications of SFOV gamma camera have been reported were in radioguided surgery such as sentinel node localisation for breast [34,47,68,[207][208][209], melanoma [58,210,211], penile [63] as well as head and neck tumours [67,209], radioguided occult lesion localisation [158], radioactive seed localisation [165] and primary hyperthyroidism [66,212]. ...
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Objective: To determine the utility of several perioperative adjuncts for parathyroid localization during parathyroid surgery, we prospectively compared the accuracy of sestamibi-single photon emission computed tomography (SPECT) scanning, radioguided surgery, and intraoperative parathyroid hormone (ioPTH) testing. Summary and Background Data: Minimally invasive parathyroidectomy (MIP) is rapidly becoming the procedure of choice in patients with primary hyperparathyroidism (HPT). Several perioperative adjuncts can be used to localize parathyroid adenomas, including sestamibi-SPECT scanning, radioguided surgery, and ioPTH testing. However, the relative value of each of these technologies is unclear. Methods: Between March 2001 through September 2004, 254 patients with primary HPT underwent parathyroidectomy. All patients had preoperative imaging studies and underwent radioguided surgery with a gamma probe and ioPTH testing. The use of each perioperative adjunct was determined based on the intraoperative findings. Results: The mean age of patients was 61 +/- 1 year. The mean calcium and parathyroid hormone levels were 11.4 +/- 0.1 mg/dL and 136 +/- 6 pg/mL, respectively. Of the 254 patients, 206 (81%) had a single parathyroid adenoma, 28 (11%) had double adenomas, 19 (8%) had hyperplasia, and one had parathyroid cancer. All resected parathyroid glands were hypercellular (mean weight = 895 +/- 86 mg). The cure rate after parathyroidectomy was 98%. The positive predictive values for sestamibi scanning, radioguided surgery, and ioPTH testing were 81%, 88%, and 99.5%, respectively. Conclusions: This series is one of the largest to date that prospectively compares the use of sestamibi scanning, radioguided surgery, and ioPTH testing. Of all the perioperative adjuncts used during parathyroid surgery, ioPTH testing has the highest sensitivity, positive predictive value, and accuracy. Thus, the inherent variability of sestamibi scanning and radioguided techniques emphasizes the critical role of ioPTH testing during parathyroid surgery.
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The aims of this study were: (a) to define the accuracy of a preoperative parathyroid imaging protocol based on the combination of technetium-99m pertechnetate/technetium-99m methoxyisobutylisonitrile (99mTcO4/99mTc-MIBI) scan and neck ultrasound (US) in selecting patients with primary hyperparathyroidism (pHPT) eligible for a limited neck exploration, and (b) to investigate the potential role of the intraoperative gamma probe (IGP) in radio-guided minimally invasive surgery. 99mTcO4/99mTc-MIBI subtraction scan was performed by means of potassium perchlorate administration with the aim of effecting rapid 99mTcO4 wash-out from the thyroid. Minimally invasive surgery using an IGP was commenced some minutes following the injection of a low, 70 MBq, 99mTc-MIBI dose. Intraoperative PTH (i-PTH) was measured. On the basis of preoperative imaging, 21 pHPT consecutive patients were selected for a limited neck dissection. In 18 of them, a single parathyroid adenoma was found at surgery and IGP allowed performance of parathyroidectomy through a small, 2-2.5 cm, skin incision with a relatively short surgical duration (mean 38 min). i-PTH rapidly normalised in all cases. In two patients, a parathyroid carcinoma was diagnosed at surgery; consequently, a wide neck exploration associated with a near-total thyroidectomy was performed. No loco-regional metastatic lesions were found and i-PTH rapidly normalised after carcinoma excision. In one patient, i-PTH remained elevated after removal of the enlarged parathyroid gland which was localised by 99mTcO4/99mTc-MIBI scan and US. A bilateral exploration was needed to remove a contralateral enlarged parathyroid gland. Combined, 99mTcO4/99mTc-MIBI scan and US imaging correctly localised a single parathyroid gland in 20/21 patients (95.2%); thus, this protocol appears to be accurate enough for the preoperative selection of pHPT patients eligible for limited neck surgery. Moreover, in these selected patients the IGP seems to be helpful in performing radio-guided minimally invasive surgery.
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The aims of this study were: (a) to define the accuracy of a preoperative parathyroid imaging protocol based on the combination of technetium-99m pertechnetate/technetium-99m methoxyisobutylisonitrile (99mTcO4/ 99mTc-MIBI) scan and neck ultrasound (US) in selecting patients with primary hyperparathyroidism (pHPT) eligible for a limited neck exploration, and (b) to investigate the potential role of the intraoperative gamma probe (IGP) in radio-guided minimally invasive surgery. 99mTcO4/99mTc-MIBI subtraction scan was performed by means of potassium perchlorate administration with the aim of effecting rapid 99mTcO4 wash-out from the thyroid. Minimally invasive surgery using an IGP was commenced some minutes following the injection of a low, 70 MBq, 99mTc-MIBI dose. Intraoperative PTH (i-PTH) was measured. On the basis of preoperative imaging, 21 pHPT consecutive patients were selected for a limited neck dissection. In 18 of them, a single parathyroid adenoma was found at surgery and IGP allowed performance of parathyroidectomy through a small, 2-2.5 cm, skin incision with a relatively short surgical duration (mean 38 min). i-PTH rapidly normalised in all cases. In two patients, a parathyroid carcinoma was diagnosed at surgery; consequently, a wide neck exploration associated with a near-total thyroidectomy was performed. No loco-regional metastatic lesions were found and i-PTH rapidly normalised after carcinoma excision. In one patient, i-PTH remained elevated after removal of the enlarged parathyroid gland which was localised by 99mTcO4/99mTc-MIBI scan and US. A bilateral exploration was needed to remove a contralateral enlarged parathyroid gland. Combined, 99mTcO4/99mTc-MIBI scan and US imaging correctly localised a single parathyroid gland in 20/21 patients (95.2%); thus, this protocol appears to be accurate enough for the preoperative selection of pHPT patients eligible for limited neck surgery. Moreover, in these selected patients the IGP seems to be helpful in performing radio-guided minimally invasive surgery.
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Minimally invasive surgery for primary hyperparathyroidism has become an accepted part of endocrine surgical practice worldwide. Survey of members of the International Association of Endocrine Surgeons. Clinical practice of endocrine surgeons worldwide. Numbers of parathyroid procedures performed, types of minimally invasive procedures undertaken, and techniques used to ensure completeness of removal of hyperfunctioning parathyroid tissue as reported by the survey respondents. Of 160 surveys completed, 95 (59%) indicate that the surgeons currently perform minimally invasive parathyroidectomy and use this technique on average for 44% of patients with primary hyperparathyroidism. The most common approach is the focused technique with a small incision, either central or lateral (92% [87 respondents]), followed by a video-assisted technique (22% [21 respondents]), and a true endoscopic technique with gas insufflation (12% [11 respondents]). Techniques used to ensure completeness of resection include the quick intraoperative intact parathyroid hormone assay (68% [65 respondents]), a same-day intact parathyroid hormone assay (17% [16 respondents]), and the nuclear probe (14% [13 respondents]). The number of parathyroidectomies performed worldwide increased from 1727 in 1980 to 6977 in 2000 with the average number per surgeon increasing from 23 in 1980 to 45 in 2000. Geographically, 20 (59%) of 34 surveys from the Americas report the use of minimally invasive parathyroidectomy, 23 (56%) of 41 from the Australasian region, and 34 (49%) of 69 from Europe or the Middle East. The number of parathyroidectomies performed for primary hyperparathyroidism has increased worldwide over the past 20 years. More than half of the surgeons responding to the survey perform minimally invasive parathyroidectomy, with the most using the focused small-incision technique.
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Minimally invasive radioguided parathyroidectomy (MIRP) offers several cosmetic and surgical advantages. Intraoperative 99m-Tc sestamibi scintigraphy using a solid-state, multi-crystal gamma camera was used to perform the MIRP. We report a case of primary hyperparathyroidism treated with this surgical procedure and discuss the usefulness of intraoperative scintigraphy. The patient was a 58-year-old Japanese woman was given a diagnosis of primary hyperparathyroidism. One hour before the operation, 99m-Tc sestamibi was injected intravenously and scintigraphy was performed in the operating room before the skin incision. Sestamibi imaging revealed an abnormal uptake close to the lower right lobe of the thyroid gland and MIRP was performed. After the tumor behind the right recurrent laryngeal nerve close to the lower right lobe of the thyroid gland was removed, intraoperative scintigraphy still revealed an abnormal uptake. MIRP was continued and an abnormal parathyroid gland behind the right carotid artery near the right recurrent laryngeal nerve was identified. After removing a parathyroid adenoma from this second location, intraoperative sestamibi imaging revealed no abnormal uptake. The operation time was 80 minutes and the amount of bleeding was 12 ml. Postoperatively, serum calcium and PTH levels were within normal range. No complications were observed. Intraoperative sestamibi imaging using a portable gamma camera is useful for locating abnormal parathyroid glands.