Use of PET to monitor the response of lung cancer to radiation treatment

Approximately 170,000 people arediagnosed with lung cancer in the United States each year. Manyof these patients receive external beam radiation for treatment. Fluorine-18 2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG PET) is increasingly being used in evaluating non-small cell lung cancer and may be of clinical utility in assessing response to treatment. In this report, we present FDG PET images and data from two patients who were followed with a total of eight and seven serial FDG PET scans, respectively, through the entire course of their radiation therapy. Changes in several potential response parameters are shown versus time, including lesion volume (V_FDG) by PET, SUV_av, SUV_max, and total lesion glycolysis (TLG) during the course of radiotherapy. The response parameters for patient 1 demonstrated a progressive decrease; however, the response parameters for patient 2 showed an initial decrease followed by an increase. The data presented here may suggest that the outcome of radiation therapy can be predicted by PET imaging, but this observation requires a study of additional patients. Received 20 January and in revised form 29 February 2000     

Systemic Immune Response to Vaccination on FDG-PET/CT

A patient with newly diagnosed right lung cancer had transient ¹⁸F-fluorodeoxyglucose (FDG)-avid left axillary lymph nodes and intense splenic FDG uptake on positron emission tomography (PET)/computed tomography (CT). History revealed that the patient received a left-sided influenza vaccine 2–3 days before the examination. Although inflammatory FDG uptake in ipsilateral axillary nodes is reported, to our knowledge, this is the first report of visualization of the systemic immune response in the spleen related to the influenza vaccination on FDG-PET/CT. The history, splenic uptake and time course on serial FDG-PET/CT helped to avoid a false-positive interpretation for progressing lung cancer and alteration of the radiation therapy plan.     

Evaluation of suspected recurrent papillary thyroid carcinoma with [18F]fluorodeoxyglucose positron emission tomography

We evaluated 10 patients with suspected recurrent papillary thyroid cancer using [18F]fluorodeoxyglucose positron emission tomography (FDG PET). Prior therapy included total (n = 8) or subtotal (n = 2) thyroidectomy, radiation therapy (n = 2) and radioiodine ablation (n = 2). All patients had an 131I scan and one or more of the following imaging studies: 99Tcm-sestamibi scan. 111In-octreotide scan, sonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). Both the PET and 131I scans were negative in four patients. The PET and 131I scan results were discordant in six patients. Of the six discordant cases, five had true-positive PET scans and false-negative 131I studies. Three of these patients underwent neck lymph node dissection that showed positive histology for metastatic papillary carcinoma. Another patient had fine-needle aspiration (FNA) of a parapharyngeal mass that was also positive for papillary carcinoma. One patient was treated with radiation to the thyroid surgical bed based on an elevated serum thyroglobulin and a positive PET finding. Tumour response with a decrease in the size of the lesion was documented by a follow-up MRI scan. The remaining patient had a presumed false-positive PET scan, since a difficult hypocellular FNA of a small palpable lymph node was negative for tumour. We conclude that FDG PET is useful in the evaluation of patients with suspected recurrent papillary thyroid cancer when the 131I scan is negative.     

Value of FDG PET in the assessment of patients with multiple myeloma

OBJECTIVE: Our objective was to evaluate if whole-body PET with FDG is able to detect bone marrow involvement in patients with multiple myeloma and to assess its appearance and distribution pattern. MATERIALS AND METHODS: Seventeen whole-body FDG PET scans were performed in 13 patients with multiple myeloma. Four patients were referred for evaluation of extent of disease pretherapy and nine patients were referred for assessment of therapy response (chemotherapy, radiation therapy, bone marrow transplant). FDG PET images were evaluated for distribution and uptake pattern. Standardized uptake values were obtained to quantify FDG uptake. Results of other imaging examinations (MRI, CT, radiography), laboratory data, biopsies, and the clinical course were used for verification of detected lesions. RESULTS: FDG PET was able to detect medullary involvement of multiple myeloma. There were two false-negative results. In one patient, the radiographic skeletal survey showed subcentimeter lytic lesions within the ribs that were not detected on FDG PET and in the other patient, a lytic lesion detected on radiographs showed only mildly increased FDG uptake that was not identified prospectively. There was one false-positive FDG PET result in a patient who had undergone radiation therapy 3 weeks before PET. FDG PET was helpful in differentiating between posttherapeutic changes and residual/recurrent tumor and in assessing response to therapy. FDG PET resulted in upstaging of disease in four patients, which influenced subsequent management and prognosis. Sensitivity of FDG PET in detecting myelomatous involvement was 85% and specificity was 92%. CONCLUSION: FDG PET is able to detect bone marrow involvement in patients with multiple myeloma. FDG PET is useful in assessing extent of disease at time of initial diagnosis, contributing to staging that is more accurate. FDG PET is also useful for evaluating therapy response.     

18 FDG PET监测肺癌化疗反应的临床应用

目的 ^18FDG PET监测肺癌化疗效果以调整治疗方案。方法：18例肺癌患者经化疗后1—3月行^18FDG PET全身扫描，评价化疗后疗效，18例均有CT结果比较。结果：18例复发和转移者15例，^18FDG PET发现14例，CT发现13例。原发病灶消失且无复发和转移者3例，^18FDG PET确定3例，CT检查确定2例。监测肺癌化疗效果^18FDG PET敏感性为93．3％，特异性为100％。CT检查敏感性为86．7％，特异性为66．7％。结论：^18FDG PET全身扫描监测肺癌化疗效果优于CT检查。是监测肺癌化疗效果较好的影像方法，能预测治疗效果。     

Use of serial FDG PET to measure the response of bone-dominant breast cancer to therapy

RATIONALE AND OBJECTIVES: The authors performed this study to determine the feasibility of using quantitative 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) to monitor the response of breast cancer bone metastases to therapy. MATERIALS AND METHODS: Twenty-four women with stage IV bone-dominant breast carcinoma were included in this study. Whole-body FDG PET imaging was performed at serial time points during the course of therapy. FDG PET scans were interpreted quantitatively by using the maximum standard uptake value (SUV) of the most conspicuous bone lesion at baseline FDG PET. PET results were compared to the overall assessment of response (response, stable disease, progressive disease) with a combination of conventional imaging, change in tumor marker values, and subjective symptom changes by experienced medical oncologists blinded to the findings at FDG PET. Changes in FDG SUV were also correlated quantitatively to the changes in a particular tumor marker (CA 27.29). RESULTS: The changes in FDG SUV with therapy showed correlation with the overall clinical assessment of response (P < .01). The percentage change in FDG uptake with therapy showed strong correlation with the percentage change in tumor marker value (P < .01). CONCLUSION: Preliminary results indicate that serial whole-body FDG PET can help quantitatively assess the response of breast cancer bone metastases to therapy. Prospective trials are needed to further investigate its accuracy.     

放射性肺炎对^18FDG PET在肿瘤放射治疗中作用影响的研究

目的研究放射性肺炎发生的时间规律、^18F-脱氧葡萄糖（FDG）PET图像的特点及对FDG EPT诊断的影响。方法选择胸部肿瘤施行放疗的患者共15例，放疗前后进行系列FDGPET全身检查。图像判断进行视觉分析和半定量分析。结果本组中有5例出现放射性肺炎，其图像特点为：病变为片状比较均匀的摄取增高影，边界与放疗照射野一致，且都在肺内靠后近胸膜处。截至随访结束时，例2及例4完全消失，而例1、例3仍有轻度摄取，例5则至放疗后13个月一直变化不大。放射性肺炎病变部位SLN随时间而减低，一般SUW在放疗后6个月内下降明显，其后变化较小。结论在放射治疗的各个阶段如果需要了解患者情况，FDG PET结果的判读应结合放疗病史及放射性肺炎不同时期的特点加以分析。     

Tumor Burden Assessment with Positron Emission Tomography with

Objective: In patients with advanced cancer, total tumor burden affects the likelihood of tumor response and has important implications for prognosis. The aim of this study was to select the optimum 2-[F-18]fluoro-2-deoxy-D-glucose-positron emission tomography (FDG PET) tumor uptake parameter to accurately measure tumor burden in advanced metastatic renal cell cancer, in comparison with volumes measured with computed tomography (CT), as a reference test.Materials and Methods: Six patients with metastatic renal cell carcinoma measurable on CT were studied. CT and FDG PET scans were carried out on all patients within 4 weeks prior to their entry into a phase I-II radioimmunotherapy trial. CT-based evaluation of disease extent (tumor volume) and 4 PET-based measurements (standardized uptake value[SUVmax], SUVav, volume, and total lesion glycolysis [TLG]) were performed independently by a radiologist (VN) and a nuclear medicine physician (TA). The degree of correlation between conventional (CT) extent of disease and parameters describing tumor concentration of FDG was then determined.Results: Fifty-seven CT-measurable metastatic lesions in lung, abdomen, and scalp were evaluated in 6 patients. There was a high correlation between CT and FDG PET volume estimates for lesions greater than 5 cm(3) in size. However, a PET-derived parameter that embodies both FDG uptake and lesion size, the TLG, correlated better with CT-derived tumor volume than did FDG PET volume alone.Conclusion: Using CT volume as a gold standard, the optimal PET-based estimate of total tumor burden in patients with metastatic renal cancer is the sum over all lesions of the total lesion glycolysis.     

F-18 FDG PET/CT evaluation of radiotherapy response in rare case of mucosa-associated lymphoid tissue lymphoma

We experienced two cases of mucosa-associated lymphoid tissue (MALT) lymphoma arising at unusual locations and used F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) to evaluate their response to radiation therapy (RT). A 62-year-old male with proven prostatic MALT lymphoma and a 43-year-old woman with proven duodenal MALT lymphoma had diffuse FDG uptake in the lesion. Both cases were treated with RT; following FDG, PET/CT showed decreased FDG uptake in each lesion. Neither patient had evidence of recurrence at more than 18 months after RT. FDG PET/CT is useful for indicating the treatment site in MALT lymphoma and in evaluation of therapeutic response following RT.     

FDG PET/CT for assessing the resectability of NSCLC patients with N2 disease after neoadjuvant therapy

Objective

Neoadjuvant chemoradiotherapy (CMRT) is the most effective treatment of stage III non-small-cell lung cancer (NSCLC). The present study aimed at assessing FDG PET/CT for defining the response of N2 disease to neoadjuvant CMRT, as surgical resection after such therapy significantly improves 5-year survival in responding N2 disease.

Methods

Forty-five patients with locally advanced NSCLC underwent both pre-neoadjuvant therapy FDG PET/CT and post-neoadjuvant therapy FDG PET/CT followed by anatomical resection of lung and ipsilateral mediastinal lymph nodes (LN). Seventeen of these patients who had PET/CT studies in our institution and were operated after CMRT were retrospectively included in the study group (12 males, ages 43–78 years; stage IIIA: 14 patients, stage IIIB: 3 patients). PET/CT response in N2 was visually scored per-lymph node station and per patient. Quantitative N2 response was evaluated by SUV_max and total lesion glycolysis (TLG) measurements after therapy alone and in comparison with pre-therapy values. PET/CT N2 response was confirmed at surgery.

Results

Seventeen NSCLC patients with 29 metastatic N2 lymph nodes (LN) were assessed. Histopathology confirmed 14 responders and 3 non-responders, and was available in 20/29 metastatic LN, showing complete response in 17 and residual disease in 3 LN. LN-based visual analysis of N2 response on PET/CT defined 3 TP, 16 TN and 1 FP, for sensitivity, specificity, accuracy, negative and positive predictive values (NPV and PPV) of 100, 94, 95, 100 and 75 %, respectively. Patient-based visual analysis defined 3 TP, 13 TN and 1 FP study, for sensitivity, specificity, accuracy, NPV and PPV of 100, 93, 94, 100 and 75 %, respectively. Nodal-based quantitative analysis of FDG uptake in N2 nodes revealed a significant difference between responding and non-responding LN only of SUV_max post-therapy (2.5 ± 1.21 vs. 3.5 ± 2.36, P = 0.04).

Conclusion

FDG PET/CT after neoadjuvant therapy accurately defined response in metastatic N2 nodes of NSCLC patients, presenting very high sensitivity and NPV for detecting responding nodes. PET/CT may enable selection of candidates for curative resection of stage III NSCLC. Mediastinoscopy may not be mandatory in patients with a negative PET/CT after neoadjuvant therapy.

     

Prognostic value of thoracic FDG PET imaging after treatment for non-small cell lung cancer

OBJECTIVE: We determined the prognostic value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for patients with treated lung cancer. MATERIALS AND METHODS: We examined patients who underwent FDG PET after first-line treatment for non-small cell lung cancer. FDG PET results were correlated with survival rates to determine whether FDG PET findings were predictive of outcomes. RESULTS: After initial therapy, 113 patients with non-small cell lung cancer underwent FDG PET. One hundred patients had positive FDG PET results and a median survival of 12 months (95% confidence interval, 9.2-15.4). Thirteen patients had negative FDG PET results, and 11 (85%) of these patients are still living at a median follow-up of 34 months. The difference in survival for patients with positive and negative FDG PET results was statistically significant (p = 0.002). CONCLUSION: FDG PET has prognostic value and strongly correlates with survival rates of patients with treated lung cancer. Patients with positive FDG PET results have a significantly worse prognosis than patients with negative results. Additionally, FDG PET may be helpful in guiding therapeutic treatments.     

Positron emission tomography with fluorine-18 fluorodeoxyglucose to evaluate response of early breast carcinoma treated with stereotaxic interstitial laser therapy

Stereotaxic interstitial laser therapy is a promising new alternative to surgery to treat early-stage breast cancer. With this, laser energy coagulates the tumor with controlled heat, leading to fibrosis. Fluorodeoxyglucose positron emission tomography (FDG PET) scanning was performed in four patients treated by this technique to determine the degree of necrosis after interstitial laser therapy. The results showed that FDG PET scanning was in close agreement with histopathologic findings, confirming complete necrosis in one patient and variable response in the other three patients. Uptake of FDG appears to be a reliable means to monitor treatment response after interstitial laser therapy and may be useful in the management of breast cancer when used with this new procedure.     

Normal thymic uptake of 2-deoxy-2[F-18]fluoro-D-glucose.

Whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) positron emission tomography (PET) of a 54-year-old woman with a history of recurrent thyroid follicular cancer and an elevated thyroglobulin level showed significant FDG uptake in the thyroid bed and anterior mediastinum. A previous scan after high-dose I-131 therapy also showed iodine uptake in these regions. Because of a lack of response to iodine therapy, the patient had surgery. Recurrent thyroid cancer was found in the neck, but the mediastinal lesion was shown to consist of normal thymus tissue. In repeated examinations performed after surgery, there was no uptake of FDG or I-131 in the anterior mediastinum. Previous treatment with a high dose of radioiodine may have contributed to visualization of a normal adult thymus with FDG PET.     

Use of 2-deoxy-2-[F-18]-fluoro-D-glucose positron emission tomography to monitor therapeutic response by rhabdomyosarcoma in children: report of a retrospective case study

PURPOSE: The purpose of this study was to study the use of 2-deoxy-2-[F-18]-fluoro-D-glucose positron emission tomography (F-18 FDG PET) for monitoring therapeutic response by rhabdomyosarcoma (RMSA) in children. PATIENTS AND METHODS: A retrospective case study was performed by searching a computer database for the patients with RMSA in whom F-18 FDG PET studies were performed pre- and posttreatment. The data of the PET studies from these patients were analyzed in conjunction with clinical treatment and other imaging studies to determine whether interval changes of F-18 FDG uptake by the RMSA reflect response of RMSA to treatment. RESULTS: Four patients with RMSA who received both pretreatment and posttreatment F-18 FDG PET studies were identified from the database and included in this study. A dramatic decrease of F-18 FDG uptake by the tumor was evident in the patients who had a favorable response to the therapy and prolonged remission of the disease. In contrast, persistent abnormal FDG uptake in one patient was associated with early relapse of the RMSA. CONCLUSIONS: F-18 FDG PET may be useful for monitoring therapeutic response by RMSA in children, which needs to be verified with a prospective study in a larger patient population.     

Evaluation of recurrent gastric malignancy with [F-18]-FDG positron emission tomography

AIM: We retrospectively assessed the use of [(18)F] fluorodeoxyglucose positron emission tomography (FDG PET) in the evaluation of recurrent disease in patients with history of gastric malignancy. MATERIALS AND METHODS: Eighteen patients were referred for FDG PET for evaluation of recurrent gastric cancer. Prior treatments included total (n = 4) or partial gastrectomy (n = 14) followed by chemotherapy alone (n = 7) or combined chemoradiation therapy (n = 2). The interval between the most recent treatment and PET ranged from 3 months to 2 years. Correlative diagnostic data were available in 16 patients and were all obtained within 3 months of the PET study. Validation was by clinical or imaging follow-up (2-45 months) in 16 patients and histology in two patients. RESULTS: PET was concordant with computed tomography (CT) in 12 patients (5 TP, 6 TN, 1 FN). In one patient with negative imaging studies, an incidental finding of left obstructive uropathy was determined to be due to metastatic ureteral stricture. Discordant imaging findings were present in four patients (22% of total). PET-detected diffuse metastatic lesions in three of these patients with rising serum tumour markers while other imaging studies were negative. Additional chemotherapy was initiated in these three patients (17% of total) based on PET localization of disease. PET and a gastric anastomosis biopsy were negative in another patient with positive CT. The remaining two patients without correlative imaging studies died shortly after positive PET studies with presumed recurrent cancer. CONCLUSION: FDG PET may be useful in the evaluation of recurrent gastric cancer, and can localize the disease when CT is non-diagnostic. Imaging evaluation with PET may also impact on the clinical management of patients with recurrent gastric cancer.     

Application of fluorodeoxyglucose positron emission tomography in the management of head and neck cancers

The use of fluorodeoxyglucose positron emission tomography (FDG PET) scan technology in the management of head and neck cancers continues to increase. We discuss the biology of FDG uptake in malignant lesions and also discuss the physics of PET imaging. The various parameters described to quantify FDG uptake in cancers including standardized uptake value, metabolic tumor volume and total lesion glycolysis are presented. PET scans have found a significant role in the diagnosis and staging of head and neck cancers. They are also being increasingly used in radiation therapy treatment planning. Many groups have also used PET derived values to serve as prognostic indicators of outcomes including loco-regional control and overall survival. FDG PET scans are also proving very useful in assessing the efficacy of treatment and management and follow-up of head and neck cancer patients. This review article focuses on the role of FDG-PET computed tomography scans in these areas for squamous cell carcinoma of the head and neck. We present the current state of the art and speculate on the future applications of this technology including protocol development, newer imaging methods such as combined magnetic resonance and PET imaging and novel radiopharmaceuticals that can be used to further study tumor biology.     

Iatrogenic artifacts on whole-body F-18 FDG PET imaging

PURPOSE: Whole-body F-18 FDG PET images frequently show artifacts related to medical and surgical interventions. We present some of the common artifact patterns in this atlas article. MATERIALS AND METHODS: We studied whole-body F-18 FDG PET images of 30 adult patients (17 males and 13 females). Of these, 9 patients had lymphoma, 7 had colon cancer, 6 had lung cancer, 3 had lung nodules, 2 each had breast and bladder cancer, and 1 patient had brain cancer. All patients had a history of some surgical or medical intervention for malignant or some other associated disease. RESULTS: PET images of 8 patients showed artifacts related to implanted prostheses and ports and 9 patients showed artifacts related to percutaneous insertion or opening of catheters, tubes, and stomas. Six patients had artifacts from previous surgery, 3 from previous radiation therapy, 3 from previous chemotherapy, and 1 from changes in glucose metabolism. CONCLUSIONS: Medical and surgical interventions can give rise to artifacts on whole-body F-18 FDG PET images. The possibilities and patterns of these artifacts should be kept in mind while reporting these studies.     

A comparative study of 11C-choline PET and [18F]fluorodeoxyglucose PET in the evaluation of lung cancer

The purpose of this study was to compare the diagnostic value of 11C-choline positron emission tomography (PET) and [18F]fluorodeoxyglucose (FDG) PET imaging in the detection of primary lung cancer and mediastinal lymph node metastases. Seventeen patients with histologically proven primary lung cancer were examined with both 11C-choline and FDG PET within a week of each study. Lung cancers were analysed visually and semiquantitatively using the ratio of tumour-to-normal radioactivity (T/N ratio) and standardized uptake value (SUV). Mediastinal lymph node metastases were analysed visually. Although both techniques delineated focal lesions with an increase in tracer accumulation in 13 patients, FDG PET identified three additional patients in whom 11C-choline PET did not visualize any lesion. In the detection of lung cancer <2 cm in size, FDG PET provided higher sensitivity (six of seven, 85.7%) than 11C-choline PET (four of seven, 57.1%). The T/N ratio and SUV were significantly higher with FDG PET (T/N ratio, 7.43+/-6.22; SUV, 4.05+/-3.05) than these were with 11C-choline PET (T/N ratio, 2.93+/-1.19; SUV, 2.93+/-0.79) (P<0.001). There was a significant positive correlation between the T/N ratios and SUVs of FDG and 11C-choline. In the assessment of mediastinal lymph node involvement, FDG PET detected lymph node metastases in two patients who were negative on 11C-choline PET, whereas both techniques could not detect tumour involvement in one patient. Both techniques have clinical value for the non-invasive detection of primary lung cancer that is 2 cm or greater in size. However, FDG PET is superior to 11C-choline PET in the detection of lung cancer that is less than 2 cm in diameter and in mediastinal lymph node metastases.     

Radiation-induced myositis mimicking chest wall tumor invasion in two patients with lung cancer: a PET/CT study

Two patients with lung cancer who had undergone stereotactic body radiation therapy (SBRT) exhibited increased F-18 FDG uptake in the chest wall after 6 months and 18 months, respectively, after SBRT. The prescribed dose of 50 Gy to the planning target volume was delivered on 4 consecutive days in each patient. It is important for nuclear medicine physicians to be familiar with F-18 FDG PET/CT findings ascribed to radiation-induced myositis in lung cancer patients treated with SBRT so that an appropriate differential diagnosis can be established.     

Early clinical experience and impact of 18F-FDG PET

PURPOSE: To determine the influence and impact of [F]- fluorodeoxyglucose positron emission tomography (FDG PET) in Denmark. METHODS: A standardized questionnaire was sent to the referring physicians of 743 consecutive cases between January 2000 and December 2001. The questionnaire was designed to determine whether and how the results of the FDG PET imaging changed patient management. RESULTS: The response rate was 71% (524 responded). The distribution of all responding physicians included 26 different specialities. The majority were from haematology (23%), oncology (20%), plastic surgery (17%) and neurology (10%). The primary diagnoses at referral was in the field of oncology (94%), with lymphoma (24%), melanomas (20%), unknown primary neoplasms (13%), nervous system neoplasms (9%), lung cancer (6%) and cancer of the digestive system (4%). FDG PET imaging resulted in a change in the patients' management in 224 cases (43%). Of these, surgery was affected in 88 cases. Chemotherapy was affected in 71 cases and radiation therapy in 54 cases. In patients where the intended plan of management was not changed, 78% of the physicians stated that FDG PET was nevertheless clinically helpful; for example confirmed the diagnosis, helped staging, changed treatment plan or confirmed treatment of choice. Physicians indicated a general satisfaction with FDG PET imaging in 86% of the cases. CONCLUSION: This survey-based study indicates that FDG PET imaging has a major impact on patient management, contributing to changes in management in 43% of cases. The present study also demonstrates that referring physicians are generally satisfied with FDG PET imaging in 86% of the cases.