Radiation oncology and functional imaging

2005 ◽  
Vol 44 (S 01) ◽  
pp. S38-S40
Author(s):  
Th. Herrmann

Summary:PET/CT imaging is most likely to be of use in radiation oncology with patients who have poorly defined target volume areas, e.g. brain tumours, bronchogenic carcinoma, and cases of miscellaneous geographical miss. Other tumours that call for dose escalated radiotherapy, such as head and neck tumours, bronchogenic carcinoma, and prostate carcinomas may further benefit from an accurate delineation of the metabolically active tumour volume and its differentiation from surrounding healthy tissue, or tumour atelectasis.

2021 ◽  
Vol 10 (4) ◽  
pp. 3199-3201
Author(s):  
Anurag A. Luharia

Advancements in Radiation Oncology from conventional to 3D conformal radiotherapy treatment demands expertise in many steps of radiation planning, the horizon of radiologist is now expanded by many folds and made radiologist as a integral part of the Radiation Oncology Department. A critical aspect of radiotherapy treatment planning (RTP) is determining how to deliver the required radiation dosage to cancer cells while minimising the exposure to normal tissue for which the prerequisite is identification and accurate delineation of tumour volume as well as normal structure resulted in an increase in the therapeutic ratio by reducing complication associated with normal tissue and allowing for higher target dosage and better local control. In modern radiotherapy CT images are the standard set of imaging modality required for the radiotherapy planning along with it many other modalities like MRI, PET or DSA are used by superimposing on original CT images in order to contour or delineate the structures defined by International Commission on Radiation Units and Measurements in Reports 50, 62 and 71 (ICRU) for radiotherapy planning which comprise of Gross tumour volume, clinical target volume, planning target volume, irradiated volume, Internal target volume and the normal structures as Organ at risk. It is self-evident that the contribution of a radiologist with a thorough knowledge of the development of these new modalities is critical for optimising the potential of these novel modes of radiation treatment delivery.


2005 ◽  
Vol 32 (12) ◽  
pp. 1392-1399 ◽  
Author(s):  
Ernesto Brianzoni ◽  
Gloria Rossi ◽  
Sergio Ancidei ◽  
Alfonso Berbellini ◽  
Francesca Capoccetti ◽  
...  

2005 ◽  
Vol 32 (12) ◽  
pp. 1491-1491
Author(s):  
Ernesto Brianzoni ◽  
Gloria Rossi ◽  
Sergio Ancidei ◽  
Alfonso Berbellini ◽  
Francesca Capoccetti ◽  
...  

2010 ◽  
Vol 10 (4) ◽  
pp. 272-282 ◽  
Author(s):  
Metin Guden ◽  
Cemile Ceylan ◽  
Kezban Berberoglu ◽  
Semih Dogan ◽  
Nadir Kucuk ◽  
...  

AbstractThe effectiveness of PET-CT (positron emission tomography–computed tomography) was investigated for staging target delineation compared with CT-MR (computed tomography–magnetic resonance) and early response of intensity-modulated radiotherapy (IMRT). Gross tumour volume–clinical target volume (GTV-CTV) differences between PET-CT and CT-MR for 14 nasopharyngeal carcinoma (NPC) patients were compared. Evaluation of doses of organs at risk (OARs) was done by IMRT plans. Responses of IMRT were evaluated with both sets. PET-CT changed MR-based TNM (Tumour Lymph Nodes Metastasis) in 11 of 14 patients. The median GTVNP (nasopharyx gross tumour volume) was 49.25 and 18.8 cm3 for CT-MR and PET-CT, respectively. In eight cases, GTVNP in the PET-CT was smaller than the CT-MR. The PET-CT presented a larger GTVNP than the CT-MR for six cases. Mean doses for the parotid glands were found to be higher than in CT-MR-based plan in one patient although he had smaller GTVNP at the PET-CT. The median follow-up was 16 months. Only one patient experienced recurrence in the CTVNP (nasopharyx clinical target volume). MR showed a decrease in the size-number of lymph nodes in four patients whereas PET-CT showed no uptake. All patients had positive responses to IMRT in their second control MR and PET-CT. PET-CT could improve tumour delineation. This enables an increase in dose inside the CTV. PET-CT provided significant information on the control scans for most of our patients whose MR imaging showed residual or recurrence.


2016 ◽  
Vol 32 ◽  
pp. 149
Author(s):  
M. du Toit ◽  
A. Potgieter ◽  
M. Heunis ◽  
R. Boellaard ◽  
J. Pruim

2012 ◽  
Vol 12 (2) ◽  
pp. 187-194
Author(s):  
S. Barrett ◽  
R. Appleyard

AbstractIntroduction: PET–CT scans are commonly used for the purpose of gross tumour volume (GTV) delineation in head and neck cancers. Qualitative visual methods (QVM) are currently employed in most radiotherapy departments but these are subject to inter- and intra-observer variability. Quantitative thresholding methods which appear in the published literature are evaluated with respect to their reliability for delineation of GTVs in head and neck cancers.Discussion: Image segmentation involves the application of a distinct value to all pixels or voxels in an image dataset. This is a complex process affected by numerous variables. Some of the following segmentation thresholds may be applied to automatically delineate specified regions. Standardised uptake value (SUV) is commonly used to apply a threshold for GTV delineation, however this leads to inappropriately large GTVs. A further common quantitative threshold is based on the maximum signal on the PET image relative to the background uptake, known as signal to background ratio (SBR). This method generates GTVs that correlate well with surgically removed tumour volumes. Applying a fixed threshold of a percentage of the maximal intensity uptake is also documented in the literature but was found to be unsuitable for the purpose of head and neck GTV contouring. Systems based on the physical features of the PET-CT images are also discussed and are found to produce very promising results.Conclusion: A number of quantitative techniques are evaluated and currently the most suitable is found to be SBR, however even this method was not found to be entirely reliable. More promising techniques need further evaluation before they could be implemented clinically and a Radiation Oncologist or Nuclear Medicine Radiologist must still validate all GTVs produced by quantitative methods.


Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 870
Author(s):  
Alessandro Bevilacqua ◽  
Diletta Calabrò ◽  
Silvia Malavasi ◽  
Claudio Ricci ◽  
Riccardo Casadei ◽  
...  

Predicting grade 1 (G1) and 2 (G2) primary pancreatic neuroendocrine tumour (panNET) is crucial to foresee panNET clinical behaviour. Fifty-one patients with G1-G2 primary panNET demonstrated by pre-surgical [68Ga]Ga-DOTANOC PET/CT and diagnostic conventional imaging were grouped according to the tumour grade assessment method: histology on the whole excised primary lesion (HS) or biopsy (BS). First-order and second-order radiomic features (RFs) were computed from SUV maps for the whole tumour volume on HS. The RFs showing the lowest p-values and the highest area under the curve (AUC) were selected. Three radiomic models were assessed: A (trained on HS, validated on BS), B (trained on BS, validated on HS), and C (using the cross-validation on the whole dataset). The second-order normalized homogeneity and entropy was the most effective RFs couple predicting G2 and G1. The best performance was achieved by model A (test AUC = 0.90, sensitivity = 0.88, specificity = 0.89), followed by model C (median test AUC = 0.87, sensitivity = 0.83, specificity = 0.82). Model B performed worse. Using HS to train a radiomic model leads to the best prediction, although a “hybrid” (HS+BS) population performs better than biopsy-only. The non-invasive prediction of panNET grading may be especially useful in lesions not amenable to biopsy while [68Ga]Ga-DOTANOC heterogeneity might recommend FDG PET/CT.


Endocrines ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 28-36
Author(s):  
Ludovica Magi ◽  
Maria Rinzivillo ◽  
Francesco Panzuto

Owing to the rarity and the biological and clinical heterogeneity of gastroenteropancreatic neuroendocrine neoplasia (GEP NEN), the management of these patients may be challenging for physicians. This review highlights the specific features of GEP NEN with particular attention on the role of Ki67 heterogeneity, the potential prognostic role of novel radiological techniques, and the clinical usefulness of functional imaging, including 68Ga-DOTA-SST PET/CT and 18F-FDG PET/CT. Understanding these specific features may help to plan proper and tailored follow-up programs and therapeutic approaches.


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