head and neck cancer head and neck cancer

PET/CT applications in PET/CT applications in

head and neck cancer head and neck cancer

黃淑華

高雄長庚醫院核子醫學科

高雄長庚紀念醫院正子斷層造影中心

高雄長庚紀念醫院正子斷層造影中心

Positron Emitters Positron Emitters

(Cyclotron) (Cyclotron)

„„ FF--18 (108 min)18 (108 min)

-- FDG (FDG (glycolysisglycolysis/cardiac viability/cerebral /cardiac viability/cerebral metabolism)

metabolism)

„„ CC--11 (20 min)11 (20 min)

-- MethionineMethionine (amino acid metabolism)(amino acid metabolism)

„„ NN--13 (10 min)13 (10 min)

-- Ammonia (myocardial perfusion)Ammonia (myocardial perfusion)

„„ OO--15 (2 min)15 (2 min)

-- water (cerebral perfusion)water (cerebral perfusion)

„„

Oncologic application Oncologic application

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Neurologic application Neurologic application

„„

Psychologic Psychologic disorders disorders

„„

Cardiac application Cardiac application

Applications of PET/CT Applications of PET/CT

„„

Lung cancer Lung cancer

„„

Head and neck tumor Head and neck tumor

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Colorectal Colorectal

„„

Lymphoma Lymphoma

„„

Melanoma Melanoma

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Thyroid cancer Thyroid cancer

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Breast cancer Breast cancer

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Esophagus Esophagus

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Seizure disorder Seizure disorder

Patient preparation Patient preparation

¾¾ No vigorous exercise for one day

No vigorous exercise for one day

¾¾ Fasting> 4 hours except water

Fasting> 4 hours except water

¾¾ Early morning appointment for DM patient

Early morning appointment for DM patient

¾¾ No pregnancy for female patient

No pregnancy for female patient

¾¾ Check Blood sugar < 150 mg

Check Blood sugar < 150 mg

FDG PET in head and neck FDG PET in head and neck

cancer cancer

„„ Staging of head and neck cancer

Staging of head and neck cancer

„„ Primary tumor evaluation by PETPrimary tumor evaluation by PET

„„ Regional nodal staging by PETRegional nodal staging by PET

„„ Distant staging by PETDistant staging by PET

„„ Diagnosis of unknown primary tumor

Diagnosis of unknown primary tumor

„„ Treatment planning

Treatment planning

„„ Therapeutic monitoring

Therapeutic monitoring

„„ Assessment of recurrent head and neck cancer

Assessment of recurrent head and neck cancer

Normal FDG uptake, variants, and pitfalls Normal FDG uptake, variants, and pitfalls

PET/CT in T staging PET/CT in T staging

„ Sensitive and specific: more than 90% to 95%

„„ Limited in primary tumor extension delineation.

Limited in primary tumor extension delineation.

„„ Dental artifacts on CT or MR images.

Dental artifacts on CT or MR images.

„„ The

The

radiotherpy

planning especially by

delineating the gross tumor volume in intensity

-

modulated

modulated raidation

raidation

therapy (IMRT)

Bone Invasion in Patients with

Oral Cavity Cancer:

Comparison of Conventional CT with PET/CT and SPECT/CT

Radiology 2005

a In the non-attenuation-corrected PET image (filtered back-projection), white spots at the site of non-removable metallicdental artwork are visible.

b An artefact mimicking FDG uptake adjacent to the metallic foreign body is present on the identical slice when using attenuation correction (iterative reconstruction).

c In the co-registered PET/CT image, interpretation of this region is impossible.

a Dental fillings in a non-attenuation-corrected PET image in another patient.

b, c After applying attenuation correction, pseudo-uptake is present adjacent to the metallic dental bridgework. There is a difference between the PETGe68 image (b) and the PETCT scan (c)

• 54-y-old male patient with squamous cell carcinomas of right retromolar area

Standardized uptake value

Tissue activity (uCi/cc)

Administered activity (uCi/g)

SUV =

Mean ROI activity (mCi/ml)

Injected dose (mCi)/body wt(g)

=

Factor affecting SUV

•

•

•

•

•

•

PET/CT in N staging PET/CT in N staging

„ PET has a high positive predictive value, greater than 90% to 95%, and is superior to CT and

MRI with respect to sensitivity and specificity in the detection of nodal disease.

„ PET is useful in identifying distant metastases and synchronous second malignancies that may not have been detected on routine conventional imaging.

„ Some series have reported a detection rate of previously unrecognized distant metastases of 27%.

Distant Metastases Staging (M0) and Detection of Synchronous Primary

Tumors

Limitations Limitations

„„ Low grade malignanciesLow grade malignancies

„„ Small lesionSmall lesion

-- Size detectable is a function of reconstructed Size detectable is a function of reconstructed resolution and contrast

resolution and contrast

-- Partial volume effect or respiratory motionPartial volume effect or respiratory motion -- <1mm<1mm

„ Limited ability to distinguish between residual or recurrent tumor from scar

„ Inability to biologically characterize disease

„ Inflammatory diseases

Diagnosis of unknown primary Diagnosis of unknown primary

tumor tumor

„ There have been conflicting reports with respect to the usefulness of PET in this setting.

„ In a review of the published series by Rusthoven and colleagues17 the overall ability of PET to detect the occult primary was 25-49%, with a

sensitivity, specificity, and accuracy of 88%, 75%, and 79%, respectively.

INITIAL MANAGEMENT

„ The ability of PET to alter the TNM staging following conventional imaging, mainly N and M staging

„ Connell and colleagues found PET/CT altered the TNM staging in 34% of patients, with 10/35 patients up-staged and 2/35 down-staged. In

most cases the alteration was attributable to a change in N staging.

Clinically Node-Negative Neck (N0)

„ clinical/radiologic N0 is based on perceived risk for less than 15% to 20% occult neck disease

„ PET: Positive predictive value : 90% ~ 95%;

Negative predictive value : 50% ~ 85%.

„ Ng and colleagues assessed the usefulness of PET, CT, and MRI in patients who had oral cavity SCC and a

palpably N0 neck

„ 134 patients, 26% were found to have neck metastases

„ The sensitivity of PET was 51% and this increased after visual correlation with CT/MRI to 57%.

Radiotherapy Planning

PET fusion with RT planning CT scans to assist with definition of tongue base tumor

Post-Radiotherapy Restaging

„ Assessment of the neck following chemotherapy and RT can be difficult because of residual clinical or

radiologic abnormalities.

„ Following RT, PET/CT has the ability to distinguish whether there is ongoing metabolic activity within

residual structural abnormalities and has a high negative predictive value, in excess of 95%.

„ Yao and colleagues assessed the role of PET at a

median of 15 weeks following definitive RT and found the negative predictive value was 100%.

„ The optimal time for a restaging PET seems to be 12 to 15 weeks following treatment.

THERAPEUTIC MONITORING AND PROGNOSTICATION

„ PET response following RT seems to have some role in predicting long-term outcome.

„ Brun and colleagues evaluated the metabolic response (MR) and standardized uptake value (SUV) in 47

patients who had HNSCC

„ Patients underwent a preatment PET followed by another PET after 1 to 3 weeks of radical RT

„ Low and high MR FDG PET, with median value as cutoff, was associated with complete response in 96% and 62% (P

=0 .007)

„ 5-year survival, 72% versus 35% (P 5 .0042)

RESTAGING AT RELAPSE AND SURVEILLANCE

„ In patients treated with HNSCC the 5-year rate of locoregional recurrence, second malignancy, and development of distant metastases are 40%

to 50%, 10% to 30%, and 15% to 20%, respectively.

NOVELTRACERS AND CLINICAL IMPLICATIONS

„ Hypoxia imaging

„ Hypoxia has long been recognized as an adverse determinant of RT treatment outcome in head and neck cancer

„ 18F-labelled FMISO PET

„ fluorine-18 fluoroazomycin arabinoside (FAZA) PET

FDG PET demonstrating uptake at the tongue base and level II node with the FAZA PET demonstrating hypoxia in the node only.

„ Proliferation Imaging

„ Increased proliferation is one of the hallmarks of cancer cells.

„ fluorine-18 fluoro-deoxy-L-thymidine (FLT)

„ Novel tracers, such as fluorine-18

fluoromisonidazole (FMISO) and fluorine-18

„ fluoro-deoxy-L-thymidine (FLT), are being evaluated in their ability to biologically

characterize

„ disease and provide prognostic information