Fluorine-18-labeled boronophenylalanine positron emission tomography for oral cancers: Qualitative and quantitative analyses of malignant tumors and normal structures in oral and maxillofacial regions

Abstract

Abstract. The present study aimed to demonstrate the features of fluorine-18-labeled boronophenylalanine positron emission tomography ( 18 F-BPA-PET) to reveal oral cancer, as well as normal structures in the oral and maxillofacial regions. We analyzed 18 F-BPA-PET findings from 8 patients with histologically confirmed recurrent and/or advanced oral cancer scheduled for boron neutron capture therapy. The capacity of 18 F-BPA-PET to delineate tumor and normal structures was assessed qualitatively and quantitatively. Tumors were easily identified as high uptake areas in all cases. Although the eyes, which were depicted as a low uptake area, and tongue musculature were readily identified, major vessels were not noted in any of the cases. Areas corresponding to the surface of the dorsum tongue to middle pharynx were expressed as high uptake areas in all of the cases. Quantitatively, tumors were expressed as the highest uptake area in 6 of the 8 cases, while the dorsum tongue had the highest uptake area in the remaining 2 cases.18 F-BPA-PET is useful in demonstrating the presence of a tumor. Thus, it is crucial to note the presence of a high uptake area corresponding to the dorsum area of the tongue when diagnosing a tumor using this technique. IntroductionFluorodeoxyglucose (FDG) positron emission tomography (PET) has recently become widely used for detecting malignant tumors of the oral cavity, particularly for the diagnosis of metastatic deposits (1). In addition, another type of PET method, methionine-basis PET, has been shown to be useful for diagnosing malignancies (2).Boron neutron capture therapy (BNCT) was recently performed in order to regulate non-resectable advanced and/or recurrent oral cancers, and its clinical utility was previously reported (3,4). However, certain patients suffer from alopecia and/or mucositis after undergoing BNCT (3,5). For planning, as well as predicting the outcome and adverse effects of this therapy, boron concentrations should be evaluated in surrounding normal structures as well as in the tumor itself, for which fluorine-18-labeled boronophenylalanine ( 18 F-BPA) PET was utilized. To the best of our knowledge, features of normal tissues and tumors in 18 F-BPA-PET images have yet to be adequately assessed. The present study therefore aimed to qualitatively and quantitatively elucidate the features of normal structures in the oral and maxillofacial regions, as well as associated tumors revealed by 18 F-BPA-PET imaging. Materials and methodsThe study evaluated 18 F-BPA-PET images obtained in examinations of 8 patients with histologically confirmed recurrent and/or advanced oral cancer, or metastatic lymphadenopathy who were scheduled for BNCT (Table I). Seven of the patients were treated with a combination of surgery, chemotherapy and radiotherapy, while 1 patient was treated with thermotherapy. All PET examinations were performed using an ECAT ACCEL (Siemens Japan Co., Tokyo, Japan) with 18 F-labeled BPA (37-55.5 MBq/10 kg of body weight) injected 45 min prior to obtaining the im...

Dynamic changes in 18F-borono-L-phenylalanine uptake in unresectable, advanced, or recurrent squamous cell carcinoma of the head and neck and malignant melanoma during boron neutron capture therapy patient selection

“…Two different tumor types were examined in our study. Our 18 F–BPA findings for SCC were consistent with previous studies [ 28 , 31 ]. However, the characteristics of dynamic 18 F–BPA accumulation in radioresistant head and neck carcinomas, such as mucoepidermoid carcinomas and adenoid cystic carcinomas, is unknown [ 3 ].…”

Reliable radiosynthesis of 4-[10B]borono-2-[18F]fluoro-l-phenylalanine with quality assurance for boron neutron capture therapy-oriented diagnosis

“…From these results and the stability of l -[ 18 F]FBPA described later, eluent 10 was selected for routine clinical use because of the small amount of one additive in physiological saline and ease of eluent preparation. The clinical injection volumes of l -[ 18 F]FBPA separated with eluent 10 (1120 MBq/13.2 ml, Table 2 ), were expected to be 2.6–3.9 ml/60 kg when the radioactive injection doses in l -[ 18 F]FBPA PET were 3.7–5.55 MBq/kg [ 38 , 39 ], and one l -[ 18 F]FBPA preparation can be used for 2 subjects with one PET scanner or 3–4 subjects with two PET scanners. In four l -[ 18 F]FBPA preparations separated with eluent 10 and collected through a 0.22 µm membrane filter, sterility and apyrogenicity (< 0.0029 EU/ml) of the l -[ 18 F]FBPA injection and filter integrity (≥ 330 kPa) were confirmed.…”

4-Borono-2-18F-fluoro-l-phenylalanine PET for boron neutron capture therapy-oriented diagnosis: overview of a quarter century of research

“…This type of quantitative evaluation has not been tried in other malignant tumors; however, Morita et al recently reported that the T / N ratios of 18 F-FBPA in head and neck cancers and malignant melanoma were not significantly changed over 120 min in spite of a slight decrease in 18 F-FBPA uptake [ 85 ]. In evaluating the T / N ratio of 18 F-FBPA in patients with head and neck cancers, it is notable that the uptake of 18 F-FBPA was higher in the dorsum tongue, submandibular gland, parotid gland, and tongue in this order among normal tissues in the oral and maxillofacial regions than in normal brain [ 86 ]. The averaged ratios ( n = 8) of T / B and tumor-to-dorsum tongue were 3.25 (range 2.34–5.40) and 1.25 (range 0.95–2.10), respectively.…”