AJR ARRS: Your Link to CME
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Nakahara, T.
Right arrow Articles by Kubo, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Nakahara, T.
Right arrow Articles by Kubo, A.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
DOI:10.2214/AJR.05.0617
AJR 2006; 187:825-829
© American Roentgen Ray Society

Original Research

Value of CT Thallium-201 SPECT Fusion Imaging over SPECT Alone for Detection and Localization of Nasopharyngeal and Maxillary Cancers

Tadaki Nakahara1, Naoyuki Shigematsu1, Masato Fujii2, Etsuo Kunieda1, Takayuki Suzuki1, Chikako Tanaka3, Jun Hashimoto1 and Atsushi Kubo1

1 Department of Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan 160-8582.
2 Department of Otolaryngology, Keio University School of Medicine, Tokyo, Japan.
3 Department of Radiology, Tokyo Metropolitan Komagome Hospital, Tokyo, Japan.

Received April 9, 2005; accepted after revision July 22, 2005.

 
Address correspondence to T. Nakahara (n-tadaki0909{at}k6.dion.ne.jp).


Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
OBJECTIVE. The purpose of this study was to investigate the incremental clinical utility of CT and high-resolution SPECT fusion imaging.

MATERIALS AND METHODS. Eighteen patients with nasopharyngeal cancer or cancers around the maxilla were scanned with high-resolution SPECT at the time of initial diagnosis (18 studies) and during follow-up after chemoradiotherapy (23 studies). SPECT results were compared with histologic findings or the findings of other imaging techniques. In addition, automatic image registration without fiducial markers was performed from CT and SPECT data, and the effect of fusion imaging on the localization of abnormalities was evaluated.

RESULTS. All of the original 18 untreated lesions showed high uptake. Recurrent tumors had a tendency to show high uptake (seven of nine patients), whereas little or no uptake generally represented no recurrence (12 of 14 patients) (chi-square test with Yates correction: {chi}2 = 6.80, p < 0.01). In two patients, physiologic uptake in the unilateral prevertebral muscle was revealed on image fusion. In four of the nine recurrent nasopharyngeal cancers (44%), SPECT alone could not determine abnormalities in uptake sites, whereas CT/SPECT fusion imaging clearly localized the sites and was helpful for treatment strategy.

CONCLUSION. High-resolution thallium-201 (201Tl) SPECT has a very high detection rate in patients with nasopharyngeal cancer and cancers around the maxilla. However, the anatomic identification or localization of the uptake sites is sometimes difficult without CT/SPECT fusion imaging. This technique without external markers is practically feasible to generate clinically valid fusion images.

Keywords: CT • head and neck imaging • image fusion • maxillary cancer • nasopharyngeal cancer • nuclear imaging • SPECT • thallium-201


Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
Thallium-201 (201Tl) SPECT has unique features that enable it to reveal metabolically active tissue by virtue of its cellular uptake by malignant cells. This technique has, in fact, been used for tumor diagnosis. Although it has been claimed to be of limited utility, given the poor anatomic localization afforded by its functional imaging techniques, nuclear SPECT is still widely available, together with recent advances in CT/SPECT fusion imaging [1].

Fusion imaging of structural and functional data may appear problematic in a clinical setting. With SPECT, which has poor spatial resolution, tumor uptake is ill defined, and the size of the lesion uptake is much larger than true lesion size. Therefore, without high-resolution SPECT data, even CT/SPECT fusion imaging may not provide accurate positional identification, especially in the adjacent small structures of the head and neck. Improved SPECT is an available option for evaluating the accuracy of image fusion and for generating clinically valid fusion images.

Because the scan area includes the supraclavicular region when evaluating head and neck cancers, it is unavoidable that the scan includes a large field of view and a long rotation radius. As a result, spatial resolution is remarkably deteriorated. The limitation described was overcome by using techniques adapted from Togawa et al. [2], which are similar to our methods. Moreover, these techniques can coregister CT images without fiducial markers in the same fashion as brain image fusion.

In our study, we retrospectively investigated the incremental clinical utility of CT high-resolution SPECT fusion imaging over SPECT alone and the detection rates of SPECT in patients with nasopharyngeal cancer and cancers around the maxilla.


Figure 1
View larger version (93K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 1A —Normal and abnormal findings on thallium-201 SPECT images. 20-year-old man in complete remission from T3 N2 M0 nasopharyngeal carcinoma after chemoradiotherapy. Modified brain 201Tl SPECT image shows no pathologic uptake in scan area including nasopharynx. Physiologic uptake sites in scalp, nasal cavity, salivary glands, palate, and prevertebral muscle (arrows) are noted.

 


Figure 2
View larger version (94K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 1B —Normal and abnormal findings on thallium-201 SPECT images. 60-year-old man with untreated T1 N0 M0 nasopharyngeal carcinoma. CT/SPECT fusion image shows pathologic uptake in right side of nasopharynx (arrowhead). Physiologic uptake in nasal cavity, muscle, parotid gland, and scalp is helpful to confirm image registration accuracy (CT in gray-scale and thallium uptake in color).

 

Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Patients
From April 2002 to September 2004, 41 cases were studied with high-resolution 201Tl SPECT in the detection of primary and recurrent head and neck cancers above the level of the maxilla. Patients with no distant metastasis in which localized treatment such as radiation therapy was scheduled were included in this study. Fifteen men and three women (mean age, 56 years; range, 20-92 years) with nasopharyngeal cancer (n = 14) or cancers around the maxilla (n = 4) participated. Eighteen studies were performed soon after the initial diagnosis; 23 studies were done during the follow-up period. Two patients with nasopharyngeal cancer were excluded from this study because we could not obtain DICOM CT data to make fusion images.

All patients underwent CT and 201Tl SPECT at the time of initial and follow-up imaging. In our study, we used CT as a tool to precisely localize abnormal uptake on image fusion, rather than for its diagnostic ability. Therefore, the time interval between corresponding CT and SPECT scans was not so restricted (interval within 2 months).

SPECT, CT, and Image Fusion
Thallium-201 SPECT was performed using a triple-headed rotating gamma camera (GCA-9300A, Toshiba Medical Systems) equipped with low-energy, ultrahigh-resolution fan-beam collimators. The energy peak and window level were set at 71 keV ± 20%. SPECT scans were started 20 minutes after the IV injection of 148 MBq of 201Tl chloride. All patients were scanned in the supine position with external head restraints used in the same fashion as was done in the brain SPECT. The patient's head was introduced into the interior of a three-headed gamma camera as far as possible so the nasopharynx was entirely within the scanning field. Although this method can be applied only to head and neck cancers above the maxilla, it yields an in-plane spatial resolution of approximately 7 mm, which is comparable to the resolution obtained with PET in the late 1990s. Image data were obtained for approximately 35 minutes in 360° rotation with 90 projections in steps of 4 degrees. The matrix size for data acquisition and image reconstruction was 1.6 mm (128 x 128). Transaxial slices 1.6 mm thick were processed using a Butterworth filter (order, 8; cutoff frequency, 0.18 cycles/pixel) and reconstructed using the ordered-subset expectation maximization algorithm. As mentioned previously, full-width at half-maximum was approximately 7 mm in air at a distance of 13 cm. Neither scatter nor attenuation correction was performed. Reconstructed images were displayed at appropriate window levels to discard background noise.


Figure 3
View larger version (112K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 2A —68-year-old man with local recurrence of T4 N2c M0 nasopharyngeal carcinoma 10 months after chemoradiotherapy. Contrast-enhanced CT scan shows nasopharyngeal wall thickening on left side. No remarkable change of structural abnormality is seen when compared with CT performed 6 months after therapy.

 


Figure 4
View larger version (102K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 2B —68-year-old man with local recurrence of T4 N2c M0 nasopharyngeal carcinoma 10 months after chemoradiotherapy. CT/SPECT fusion image performed 10 months after chemoradiotherapy shows moderate uptake in thickened wall (CT in gray-scale and thallium uptake in color).

 


Figure 5
View larger version (79K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 3A —64-year-old woman with local recurrence of T4 N1 M0 nasopharyngeal carcinoma 6 months after chemoradiotherapy. Thallium-201 SPECT scan reveals moderate uptake near right side of nasopharynx (arrow).

 


Figure 6
View larger version (77K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 3B —64-year-old woman with local recurrence of T4 N1 M0 nasopharyngeal carcinoma 6 months after chemoradiotherapy. CT/SPECT fusion image shows uptake to be mainly located in clivus (CT in gray-scale and thallium uptake in color).

 


Figure 7
View larger version (80K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 3C —64-year-old woman with local recurrence of T4 N1 M0 nasopharyngeal carcinoma 6 months after chemoradiotherapy. SPECT scan after stereotactic radiosurgery to clival lesion shows remarkably reduced uptake in recurrent lesion.

 
CT data used in our study were obtained in routine clinical practice (contrast-enhanced) or to gather information for determining the radiation field (unenhanced). CT of the neck was performed from the orbit to the thoracic inlet with 5-mm collimation and a pitch of 1. Contiguous transaxial CT images 5 mm thick were obtained with a 512 x 512 matrix. CT data were transferred to a nuclear imaging workstation in DICOM format. SPECT and CT data were processed using a medical image processor (GMS-5500A/PI, Toshiba). SPECT images were automatically resliced using commercially available software (Automatic Registration Tool, Toshiba) to correspond to CT images. Ardekani et al. [3] have described the registration theory, which rests on the assumption that uniform regions shown with one technique represent uniform findings in corresponding regions on another technique, allowing segmentation of the CT images into eight ranges of voxel intensity. Eighty to 130 segments are automatically selected to perform optimal registration so that the SPECT voxel intensity variance is minimized. Fiducial markers are not required for image registration, and registration error does not exceed 3 mm. Automatic registration takes less than 5 minutes on our workstation.

SPECT Image Interpretation
Before interpretation of the 201Tl SPECT images, the evaluating nuclear medicine physician was informed of the patient's treatment history (i.e., no treatment or follow-up after treatment) but was not given details of the disease, including the presence or absence of viable tumor, location, size, or extent. Tumor uptake was classified as marked, moderate, slight, or no evidence of tumor uptake. In addition, the location where abnormal uptake was most likely to be visualized was recorded before and after CT/SPECT fusion imaging.

Diagnostic Criteria
Figure 1A shows normal 201Tl SPECT images at the superior level of the head and neck. These were obtained 26 months after chemoradiotherapy in a patient with stage T3 N2 M0 nasopharyngeal carcinoma. More than 3 years later, the patient was still in complete remission. Figure 1B shows SPECT images with abnormalities in a patient with T1 N0 M0 nasopharyngeal carcinoma in whom abnormally increased uptake is shown in the right nasopharyngeal wall. As shown in Figure 1A, it is common to find nonpathologic uptake in the scalp, nasal cavity, salivary glands, and ocular muscles, whereas bone uptake is barely visible [4]. Also, prevertebral muscles and masseters are frequently visualized. It is not rare to see uptake in the palate at the level of the maxilla.

Concerning initial diagnosis, all suspicious lesions were confirmed to be malignant by biopsy. Tumor location was determined by fiberscopic examination. In the case of recurrent tumors, histologic results obtained within 4 weeks before or after SPECT were used for diagnosis. If histopathology was not obtained or if biopsy specimens were insufficient for definitive diagnosis, the diagnosis and location of recurrences were established by follow-up imaging if the scans showed disease progression within 12 months. If follow-up imaging showed lesion regression after a minimum 6-month interval or lesion stability for a minimum of 1 year, or it failed to show any evidence of masses, the patients were considered to have a benign condition.

Statistical Analysis
Patients were classified into two groups according to SPECT findings (because of the small number of patients): those with SPECT showing marked or moderate uptake and those with SPECT showing little or no uptake. The groups' pathologic findings were compared using the chi-square test with Yates correction.


Figure 8
View larger version (92K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 4A —54-year-old man with cervical spine recurrence (or metastasis) of T4 N0 M0 nasopharyngeal carcinoma 11 months after chemoradiotherapy. Thallium-201 SPECT scan shows moderate uptake near left posterior side of nasopharynx (arrow). Uptake site cannot be determined on SPECT scan alone.

 


Figure 9
View larger version (77K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 4B —54-year-old man with cervical spine recurrence (or metastasis) of T4 N0 M0 nasopharyngeal carcinoma 11 months after chemoradiotherapy. CT/SPECT fusion image shows that uptake is located in left lateral mass of first cervical spine (CT in gray-scale and thallium uptake in color).

 


Figure 10
View larger version (97K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 4C —54-year-old man with cervical spine recurrence (or metastasis) of T4 N0 M0 nasopharyngeal carcinoma 11 months after chemoradiotherapy. T1-weighted MR image after contrast enhancement confirms recurrence (or metastasis) in same location (arrow) as shown in B.

 

Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Detection and Localization of Untreated Primary Tumors
All 18 original, untreated lesions showed marked or moderate uptake, resulting in a detection rate of 100%. Most of the lesions were large (mean, 42 ± 21 mm; range, 13-80 mm), although SPECT also detected two T1 nasopharyngeal cancers [5]. SPECT images in one of the two T1 tumors are shown in Figure 1B. Abnormal uptake sites in all nasopharyngeal cancers could be accurately localized on SPECT images (14 of 14 patients), whereas the locations of 50% of cancers around the maxilla (two of four patients) could not be determined on SPECT alone.

Detection and Localization of Recurrent Primary Tumors
Fifteen patients were studied with 201Tl SPECT during the follow-up period. Because some patients underwent follow-up SPECT several times, a total of 23 SPECT studies were evaluated. Diagnostic accuracy was based on pathologic results or clinical follow-up in 19 of the 23 SPECT studies; the remaining four studies showed abnormal uptake in bone where biopsy could not be performed.

There were nine nasopharyngeal cancer recurrences and 14 complete remissions at the time of SPECT examination. Recurrent tumors had a tendency to show marked or moderate uptake (seven of nine patients), whereas little or no uptake generally represented no recurrence (12 of 14 patients) (chi-square test with Yates correction: {chi}2 =6.80, p < 0.01). In two patients, marked or moderate uptake was visualized unilaterally in the nasopharynx. In these patients, CT/SPECT fusion imaging confirmed uptake in the normal prevertebral muscle. In the nine recurrent nasopharyngeal cancers, five (56%) showed abnormal uptake in the swollen nasopharyngeal wall. Figures 2A and 2B shows a patient in whom nasopharyngeal wall thickening barely changed 10 months after chemoradiotherapy; however, a histologically confirmed local recurrence was identified on SPECT. In this patient, chemotherapy using TS-1 was initiated after the SPECT study. SPECT alone was unable to localize the abnormal uptake site in four other recurrent tumors (44%), whereas CT/SPECT fusion imaging localized three recurrences, mainly in the clivus. Figures 3A, 3B, and 3C shows a patient who underwent stereotactic radiation therapy for a recurrent lesion in the clivus. In another patient, fusion imaging was useful in localizing a recurrent lesion in an unexpected site (Figs. 4A, 4B, and 4C).


Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
Thallium-201 can be used to assess many malignant tumors including aerodigestive cancers. We have previously reported that 201Tl uptake may be associated with the viability of esophageal cancer, and that its chemoradiotherapeutic effect can be evaluated with 201Tl SPECT [6]. Thalium-201 SPECT has been reported to have a very high accuracy in the detection of head and neck cancers [7-9], which is consistent with our results. Therefore, 201Tl SPECT may be useful in addition to established imaging techniques such as CT or MRI.

As mentioned in our previous study, in which we applied SPECT to esophageal cancer, the various limitations lowered the effectiveness of SPECT in tumor diagnosis, including relatively poor spatial resolution, noise, and strong physiologic uptake near the tumor [6]. In contrast, the method used in the present study is advantageous for the following reasons: the short distance between the patient's head and the collimator can lead to high resolution and sensitivity, SPECT with a fan-beam collimator provides higher resolution than that using a parallel-hole collimator without significant loss of sensitivity, and there are no physiologic uptake sites other than prevertebral muscle near the nasopharynx or maxilla.

Various reports describing CT/SPECT fusion imaging can be found in the literature [10-12]. In these reports, external markers were used for images registration; this differs from our method. In the case of CT/SPECT, patients are equipped with external markers for CT, and they receive radiation exposure only for image fusion. CT is the first choice and is necessary for evaluating head and neck cancers. However, in clinical practice it seems somewhat difficult to perform routine CT examinations and successive SPECT studies in keeping with external markers. Although coregistration inaccuracy is a potential problem with CT/SPECT fusion images without fiducial markers, algorithms permitting image fusion in the absence of markers have been intensively developed for brain imaging [3, 13-15]. Organs around the base of the skull are rigid; thus, image fusion accuracy in this region is comparable to that of a phantom study (error < 3 mm). In addition, high spatial resolution and certain landmarks that show physiologic uptake can enhance its accuracy.

In the present study, we did not focus on direct comparison of SPECT with other imaging techniques. Our method is insufficient for the evaluation of head and neck cancers because of the limited scan area. As shown in Figure 1B, in most cases with untreated cancers, CT alone can detect abnormalities that are suspect for malignancy. In contrast, it is sometimes difficult to detect recurrent tumors because of structural abnormalities persisting long after therapy (Figs. 2A, 2B, 3A, 3B, and 3C). Furthermore, some patients with untreated advanced cancers with bone destruction extending to the clivus had CT after chemoradiotherapy that showed somewhat improved nasopharyngeal wall thickening but persistent clival destruction. According to clinical records of diagnostic CT and our retrospective reviews, it was difficult to differentiate residual viable tumors from soft tissues with no viable cells in that morphologically changed area. Thalium-201 SPECT can detect viable tumors even after therapy [6]; thus, CT/SPECT fusion images may have significant clinical impact. Indeed, treatment was changed in the patients described in Figures 2A, 2B, 3A, 3B, 3C, 4A, 4B, and 4C.

Fluorine-18-FDG PET is useful for evaluating head and neck cancers. In our study, it took approximately 35 minutes to produce high-resolution SPECT images, which is longer than the scanning time required to obtain high-resolution whole-body tomographic images using recent PET devices. In this regard, PET seems methodologically superior to 201Tl SPECT. One advantage of 201Tl SPECT over 18F-FDG PET may be that brain uptake is negligible in SPECT scans, whereas it is very high in 18F-FDG PET scans. This makes evaluation around the clivus easier with 201Tl SPECT than with 18F-FDG PET [9]. Indeed, recurrence in the clivus is not rare. In PET/CT, the high uptake of 18F-FDG in the brain has no effect on the detection of tumor in the clivus or any other regions in the head and neck. However, false-positive 18F-FDG PET results have been reported in patients with nasopharyngeal cancer after radiation therapy [16], which may not be able to be resolved even in PET/CT. We believe that the appropriate selection of imaging techniques can enhance the utility of high-resolution 201Tl SPECT combined with CT in patients with nasopharyngeal cancer or cancers around the maxilla.

In summary, 201Tl accumulated well in nasopharyngeal cancer and cancers around the maxilla, resulting in a very high sensitivity on high-resolution SPECT. The 201Tl uptake was significantly higher in recurrent tumors than in benign conditions. However, the anatomic identification or localization of the uptake site was sometimes unclear without CT/SPECT image fusion. Fusion imaging without external markers was practically feasible to generate clinically valid images and was useful not only for excluding physiologic uptake, as shown in prevertebral muscles, but also for localizing recurrent tumor.


References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Keidar Z, Israel O, Krausz Y. SPECT/CT in tumor imaging: technical aspects and clinical applications. Semin Nucl Med2003; 3:205 -218
  2. Togawa T, Yui N, Kinoshita F, Shimada F, Omura K, Takemiya S. Visualization of nasopharyngeal carcinoma with Tl-201 chloride and a three-head rotating gamma camera SPECT system. Ann Nucl Med 1993; 7:105 -113[Medline]
  3. Ardekani BA, Braun M, Hutton BF, Kanno I, Iida H. A fully automatic multimodality image registration algorithm. J Comput Assist Tomogr 1995; 19:615 -623[Medline]
  4. Schomacker K, Schicha H. Use of myocardial imaging agents for tumour diagnosis: a success story? Eur J Nucl Med2000; 27:1845 -1863[CrossRef][Medline]
  5. Nakahara T. Tumor diagnosis in nuclear medicine: clinical usefulness and application to radiation therapy [in Japanese]. (letter) Jpn J Clin Radiol 2005;50 : 212-214
  6. Nakahara T, Togawa T, Nagata M, et al. Comparison of barium swallow, CT and thallium-201 SPECT in evaluating responses of patients with esophageal squamous cell carcinoma to preoperative chemoradiotherapy. Ann Nucl Med 2003;17 : 583-591[Medline]
  7. Gregor RT, Valdes-Olmos R, Koops W, et al. Preliminary experience with thallous chloride Tl 201-labeled single-photon emission computed tomography scanning in head and neck cancer. Arch Otolaryngol Head Neck Surg 1996; 122:509 -514[Abstract]
  8. van Veen SA, Balm AJ, Valdes-Olmos RA, et al. Occult primary tumors of the head and neck: accuracy of thallium 201 single-photon emission computed tomography and computed tomography and/or magnetic resonance imaging. Arch Otolaryngol Head Neck Surg 2001;127 : 406-411[Abstract/Free Full Text]
  9. Mukherji SK, Gapany M, Phillips D, et al. Thallium-201 single-photon emission CT versus CT for the detection of recurrent squamous cell carcinoma of the head and neck. AJNR1999; 20:1215 -1220[Abstract/Free Full Text]
  10. Scott AM, Macapinlac H, Zhang J, et al. Image registration of SPECT and CT images using an external fiduciary band and three-dimensional surface fitting in metastatic thyroid cancer. J Nucl Med1995; 36:100 -103[Abstract/Free Full Text]
  11. Chajari M, Lacroix J, Peny AM, et al. Gallium-67 scintigraphy in lymphoma: is there a benefit of image fusion with computed tomography? Eur J Nucl Med Mol Imaging 2002;29 : 380-387[CrossRef][Medline]
  12. Yamamoto Y, Nishiyama Y, Monden T, Matsumura Y, Satoh K, Ohkawa M. Clinical usefulness of fusion of 131SPECT and CT images in patients with differentiated thyroid carcinoma. J Nucl Med2003; 44:1905 -1910[Abstract/Free Full Text]
  13. Thurfjell L, Lau YH, Andersson JLR, Hutton BF. Improved efficiency for MRI-SPECT registration based on mutual information. Eur J Nucl Med 2000; 27:847 -856[CrossRef][Medline]
  14. Friston KJ, Ashburner J, Frith CD, Poline J-B, Heather JD, Frackowiak RSJ. Spatial registration and normalisation of images. Human Brain Mapping 1995;2 : 165-189
  15. Woods RP, Mazziotta JC, Cherry SR. MRI-PET registration with automated algorithm. J Comput Assist Tomogr1993; 17:536 -546[Medline]
  16. Liu S-H, Chang JT, NG S-H, Chan S-C, Yen T-C. False-positive fluorine-18 fluorodeoxy-D-glucose positron emission tomography finding caused by osteoradionecrosis in a nasopharyngeal carcinoma patient. Br J Radiol 2004; 77:257 -260[Abstract/Free Full Text]

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?



This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Nakahara, T.
Right arrow Articles by Kubo, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Nakahara, T.
Right arrow Articles by Kubo, A.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS