Publications by authors named "Ali F Yapar"

4 Publications

  • Page 1 of 1

Retrospective correlation of ga-psma uptake with clinical parameters in prostate cancer patients undergoing definitive radiotherapy.

Ann Nucl Med 2020 Jun 27;34(6):388-396. Epub 2020 Mar 27.

Faculty of Medicine, Department of Nuclear Medicine, Adana Dr Turgut Noyan Research and Treatment Center, Başkent University, Adana, Turkey.

Objective: The aim of the study is to investigate the correlation between the intensity of prostate-specific membrane antigen (PSMA) uptake in primary tumor and clinico-pathological characteristics of non-metastatic prostate cancer patients treated with definitive radiotherapy (RT).

Methods: Using the clinical data of 201 prostate cancer patients who were referred for  Ga-PSMA-positron emission tomography (PET/CT) for staging and RT planning, we analyzed the correlations among intermediate- or high-risk disease based on Gleason score (GS), prostate-specific antigen (PSA) level, D'Amico risk group classification, and maximum standardized uptake (SUV) of primary tumor.

Results: Primary tumor was visualized via  Ga-PSMA-PET/CT scan in 192 patients (95.5%). The median SUV of primary tumor and metastatic lymph node were 13.2 (range 3.3-83.7) and 11.4 (range 3.6-64.5), respectively. A significant moderate correlation was observed between PSA level and median tumor SUV as measured by  Ga-PSMA-PET/CT (Spearman = 0.425; p < 0.001). Patients with serum PSA > 10 ng/mL, GS > 7, D'Amico high-risk group classification, and pelvic lymph node metastasis had significantly higher tracer uptake in primary tumor than their counterparts. The median SUV of primary tumor was highest in patients with GS 9. The primary tumor detection rates of  Ga-PSMA-PET/CT were 83%, 92%, and 99% for patients with serum PSA ≤ 5.0 ng/mL (14 patients, 7%), PSA 5.1-10.0 ng/mL (45 patients, 22%), and PSA > 10 ng/mL (142 patients, 71%), respectively.

Conclusions: We demonstrated a correlation between prostate tumor characteristics and PSMA tracer uptake. Patients with serum PSA > 10 ng/mL, GS > 7, D'Amico high-risk group classification, and pelvic lymph node metastasis had significantly higher SUV than their counterparts. In addition, the primary tumor detection rate was higher in patients with serum PSA > 10 ng/mL and GS > 7.
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http://dx.doi.org/10.1007/s12149-020-01462-xDOI Listing
June 2020

Comparison of computed tomography- and positron emission tomography-based radiotherapy planning in cholangiocarcinoma.

Onkologie 2013 19;36(9):484-90. Epub 2013 Aug 19.

Department of Radiation Oncology, Baskent University Medical Faculty, Adana, Turkey.

Introduction: The aim of this study was to compare computed tomography (CT)- and positron emission tomography (PET)/CT-based gross tumor volume (GTV) delineation and its subsequent expansion to the planning target volume (PTV), and to analyze the resultant doses of 3-dimensional conformal radiotherapy (3D-CRT) to critical organs.

Methods: 15 patients with unresectable extrahepatic cholangiocarcinoma (EHCC) were enrolled into this study. PTVCT-based plans were initially made, and then PTVPET-CT-based plans were created using the same beam angles and isocenter. The dosimetric parameters analyzed included GTVCT, PTVCT, GTVPET-CT and PTVPET-CT. Prescribed and delivered radiation doses to target volumes and delineated organs at risk were also compared.

Results: Mean GTV and PTV were significantly reduced in the PET/CT-based plan compared to the CT-based plan; the mean reductions of GTV and PTV were 28.7% and 15.2%, respectively. The mean value for GTVPET/GTVCT mismatch was 49.5 ± 28.9%, and that for GTVCT/GTVPET was 95.9 ± 19.5%. The mean value for PTVPET-CT/PTVCT mismatch was 21.9 ± 7.0% and that for PTVCT/PTVPET-CT was 39.1 ± 9.2%. Liver doses were significantly reduced (17.1%) in the PET/CT-based plan compared to the CT-based plan; the doses received by at least 30% and 50% of the liver were 30.0%, and 27.3%, respectively.

Conclusion: The potential benefit of PET/CT is the reduction in geographic misses and regional treatment failures associated with CT-based planning.
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http://dx.doi.org/10.1159/000354630DOI Listing
May 2014

Biliary obstruction induces extremely elevated serum CA 19-9 levels: case report.

Onkologie 2012 20;35(12):780-2. Epub 2012 Nov 20.

Department of Radiation Oncology, Baskent University Faculty of Medicine, Adana, Turkey.

Background: Assessment of carbohydrate antigen (CA) 19-9 levels is used for diagnosis and follow-up of pancreaticobiliary cancers, and high levels of this biomarker are suggestive of a malignancy. CA 19-9 may also be elevated in patients with conditions other than tumors, such as cholestasis, biliary obstruction, and cholecystitis.

Case Report: A 50-year-old male patient presented with jaundice and elevated CA 19-9 levels (161,902 IU/ml). Repeated biopsies of the common bile duct revealed no malignancies. Radiological findings indicated a mass protruding through the common bile duct. Positron emission tomography demonstrated increased (18)F-fluoro2-deoxy-D-glucose uptake in the liver and a mass resembling metastasis was detected. A Whipple procedure was performed and demonstrated no tumor. Postoperatively, CA 19-9 levels decreased to within normal limits (27 IU/ml).

Conclusion: These results indicate that CA 19-9 levels should not be the sole criterion for a diagnosis of malignancy. Although other analytical tools may aid diagnosis, surgical exploration may be required in some instances to avoid misdiagnosis and determine whether radiological results are falsely positive.
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http://dx.doi.org/10.1159/000345110DOI Listing
June 2013

Preoperative evaluation of hyperparathyroidism: the role of dual-phase parathyroid scintigraphy and ultrasound imaging.

Ann Nucl Med 2008 Feb 3;22(2):123-31. Epub 2008 Mar 3.

Department of Nuclear Medicine, Adana Teaching and Medical Research Center, Baskent University Faculty of Medicine, Dadaloglu Mah, 39 Sokak, No. 6, Yuregir, 01250 Adana, Turkey.

Objective: The aim of this study was to evaluate the efficacy of dual-phase 99mTc-methoxyisobutylnitrile (MIBI) parathyroid scintigraphy (PS) and ultrasound (US) in primary (pHPT) and secondary (sHPT) hyperparathyroidism.

Methods: A total of 69 patients (mean age 47+/-16; age range 14-79 years), including 19 patients with sHPT were enrolled in this study. Preoperative serum intact parathyroid hormone (iPTH) levels, calcium (Ca), phosphate (P), alkaline phosphatase, and 24-h urinary-free Ca measurements were obtained. Concomitant thyroid pathology was also recorded.

Results: Histopathology revealed 30 solitary adenomas and 71 hyperplastic glands in 55 patients. The remaining patients' histopathology revealed normal parathyroid, thyroid, or lymph nodes. The sensitivities of MIBI and US in pHPT were 70% and 60%, respectively. It was 60% for both procedures in sHPT. The overall sensitivity of combined US + MIBI in pHPT and sHPT was 81% and 71%, respectively. The overall specificity of MIBI and US was 87% and 91%; positive predictive value (PPV) was 94% and 92%, respectively. MIBI and US identified the parathyroid pathology in 92% and 85% of patients in the non-concomitant thyroid disease group, and in 53% and 47% of patients in the concomitancy thyroid disease group, respectively. The weight of the gland between primary and secondary hyperparathyroidism did not reveal a significant difference (P=0.4). Significant differences were found with respect to age, PTH, Ca, and P levels between the pHPT and sHPT (P<0.001). Intact PTH levels showed significant differences between MIBI positive and negative patients (P=0.013), and also US positive and negative patients (P=0.012). A significant negative correlation was found between iPTH and Ca at sHPT (P<0.001).

Conclusions: The concomitant of thyroid disease greatly influences scintigraphic and ultrasonographic detection of parathyroid pathology in pHPT and sHPT. The combination of MIBI and US appears promising for localizing parathyroid pathology in patients with both primary and secondary hyperparathyroidism. The concordance rate is high together with a lower chance of missing concomitant thyroid pathology, which might alter the surgical approach.
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http://dx.doi.org/10.1007/s12149-007-0086-zDOI Listing
February 2008