Multi-modal imaging for dose planning and its benefits: the paradigm of head and neck tumours

2018 ◽  
Vol 47 (3-4) ◽  
pp. 159-159
Author(s):  
V. Grégoire
Keyword(s):  
Head And Neck ◽  
Tumour Volume ◽  
Routine Practice ◽  
Head And Neck Tumours ◽  
Normal Tissues ◽  
Adaptive Treatment ◽  
Dose Planning ◽  
Target Volumes ◽  
Treatment Morbidity ◽  
Late Treatment

The ultimate goal of any radiotherapy is to eradicate the disease without inflicting damage on the normal tissues surrounding the tumours, which could be responsible for late treatment morbidity. To achieve this objective, the first step is to precisely select and delineate the target volumes to which a given dose will be prescribed. This step requires the use of multi-modal images from clinical examination to anatomical and molecular images. Imaging examination will be used not only to delineate the boundaries of the tumour volume, but also to assess tumour heterogeneity and, possibly, to guide a heterogeneous dose prescription (i.e. the so-called ‘dose painting’ approach). Last, re-imaging the patient during treatment to assess variation of the tumour volume during radiotherapy may also be performed in the framework of adaptive treatment. Over the last decade, a lot of information has been gathered on the use of multi-modal imaging for dose planning, and its potential and technical difficulties have been identified. During the lecture, the speaker will review the state-of-the-art of multi-imaging for treatment, using head and neck tumours as a paradigm, emphasising what should be considered as routine practice and what should still be viewed as research questions. © 2018 ICRP. Published by SAGE.

scholarly journals Qualitative and Quantitative Diagnosis in Head and Neck Cancer

Diagnostics ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1526
Author(s):  
Fernando López ◽  
Antti Mäkitie ◽  
Remco de Bree ◽  
Alessandro Franchi ◽  
Pim de Graaf ◽  
...  
Keyword(s):  
Head And Neck ◽  
Prognostic Markers ◽  
Imaging Techniques ◽  
Tumour Volume ◽  
Accurate Diagnosis ◽  
Head And Neck Tumours ◽  
Quantitative Diagnosis ◽  
Qualitative And Quantitative ◽  
Different Types ◽  
The Right

The diagnosis is the art of determining the nature of a disease, and an accurate diagnosis is the true cornerstone on which rational treatment should be built. Within the workflow in the management of head and neck tumours, there are different types of diagnosis. The purpose of this work is to point out the differences and the aims of the different types of diagnoses and to highlight their importance in the management of patients with head and neck tumours. Qualitative diagnosis is performed by a pathologist and is essential in determining the management and can provide guidance on prognosis. The evolution of immunohistochemistry and molecular biology techniques has made it possible to obtain more precise diagnoses and to identify prognostic markers and precision factors. Quantitative diagnosis is made by the radiologist and consists of identifying a mass lesion and the estimation of the tumour volume and extent using imaging techniques, such as CT, MRI, and PET. The distinction between the two types of diagnosis is clear, as the methodology is different. The accurate establishment of both diagnoses plays an essential role in treatment planning. Getting the right diagnosis is a key aspect of health care, and it provides an explanation of a patient’s health problem and informs subsequent decision. Deep learning and radiomics approaches hold promise for improving diagnosis.

The reliability of quantitative thresholding methods for PET aided delineation of GTVs in Head and Neck tumours

2012 ◽  
Vol 12 (2) ◽  
pp. 187-194
Author(s):  
S. Barrett ◽  
R. Appleyard
Keyword(s):  
Head And Neck ◽  
Quantitative Methods ◽  
Tumour Volume ◽  
Head And Neck Cancers ◽  
Visual Methods ◽  
Head And Neck Tumours ◽  
Standardised Uptake Value ◽  
Complex Process ◽  
Pet Ct ◽  
Physical Features

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.

Radiation oncology and functional imaging

2005 ◽  
Vol 44 (S 01) ◽  
pp. S38-S40
Author(s):  
Th. Herrmann
Keyword(s):  
Functional Imaging ◽  
Radiation Oncology ◽  
Bronchogenic Carcinoma ◽  
Brain Tumours ◽  
Tumour Volume ◽  
Target Volume ◽  
Head And Neck Tumours ◽  
Pet Ct ◽  
Surrounding Healthy Tissue ◽  
Prostate Carcinomas

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.

A comprehensive evaluation of the quality and complexity of prostate IMRT and VMAT plans generated by an automated inverse planning tool

2021 ◽  
pp. 1-7
Author(s):  
Dean Wilkinson ◽  
Kelly Mackie ◽  
Dean Novy ◽  
Frances Beaven ◽  
Joanne McNamara ◽  
...  
Keyword(s):  
Dose Level ◽  
Comprehensive Evaluation ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Planning Tool ◽  
Inverse Planning ◽  
Dose Planning ◽  
Target Volumes ◽  
Lymph Node Irradiation

Abstract Introduction: The Pinnacle3 Auto-Planning (AP) package is an automated inverse planning tool employing a multi-sequence optimisation algorithm. The nature of the optimisation aims to improve the overall quality of radiotherapy plans but at the same time may produce higher modulation, increasing plan complexity and challenging linear accelerator delivery capability. Methods and materials: Thirty patients previously treated with intensity-modulated radiotherapy (IMRT) to the prostate with or without pelvic lymph node irradiation were replanned with locally developed AP techniques for step-and-shoot IMRT (AP-IMRT) and volumetric-modulated arc therapy (AP-VMAT). Each case was also planned with VMAT using conventional inverse planning. The patient cohort was separated into two groups, those with a single primary target volume (PTV) and those with dual PTVs of differing prescription dose levels. Plan complexity was assessed using the modulation complexity score. Results: Plans produced with AP provided equivalent or better dose coverage to target volumes whilst effectively reducing organ at risk (OAR) doses. For IMRT plans, the use of AP resulted in a mean reduction in bladder V50Gy by 4·2 and 4·7 % (p ≤ 0·01) and V40Gy by 4·8 and 11·3 % (p < 0·01) in the single and dual dose level cohorts, respectively. For the rectum, V70Gy, V60Gy and V40Gy were all reduced in the dual dose level AP-VMAT plans by an average of 2·0, 2·7 and 7·3 % (p < 0·01), respectively. A small increase in plan complexity was observed only in dual dose level AP plans. Findings: The automated nature of AP led to high quality treatment plans with improvement in OAR sparing and minimised the variation in achievable dose planning metrics when compared to the conventional inverse planning approach.

scholarly journals Synergies Radiotherapy-Immunotherapy in Head and Neck Cancers. A New Concept for Radiotherapy Target Volumes-“Immunological Dose Painting”

Medicina ◽  
2020 ◽  
Vol 57 (1) ◽  
pp. 6
Author(s):  
Camil Ciprian Mireştean ◽  
Anda Crişan ◽  
Călin Buzea ◽  
Roxana Irina Iancu ◽  
DragoşPetru Teodor Iancu
Keyword(s):  
Immune System ◽  
Synergistic Effect ◽  
Head And Neck ◽  
Multimodal Treatment ◽  
Clinical Target Volume ◽  
Locally Advanced ◽  
Target Volume ◽  
Head And Neck Cancers ◽  
Dose Painting ◽  
Target Volumes

The combination of immune checkpoint inhibitors and definitive radiotherapy is investigated for the multimodal treatment of cisplatin non-eligible locally advanced head and neck cancers (HNC). In the case of recurrent and metastatic HNC, immunotherapy has shown benefit over the EXTREME protocol, being already considered the standard treatment. One of the biggest challenges of multimodal treatment is to establish the optimal therapy sequence so that the synergistic effect is maximal. Thus, superior results were obtained for the administration of anti-CTLA4 immunotherapy followed by hypofractionated radiotherapy, but the anti-PD-L1 therapy demonstrates the maximum potential of radio-sensitization of the tumor in case of concurrent administration. The synergistic effect of radiotherapy–immunotherapy (RT–IT) has been demonstrated in clinical practice, with an overall response rate of about 18% for HNC. Given the demonstrated potential of radiotherapy to activate the immune system through already known mechanisms, it is necessary to identify biomarkers that direct the “nonresponders” of immunotherapy towards a synergistic RT–IT stimulation strategy. Stimulation of the immune system by irradiation can convert “nonresponder” to “responder”. With the development of modern techniques, re-irradiation is becoming an increasingly common option for patients who have previously been treated with higher doses of radiation. In this context, radiotherapy in combination with immunotherapy, both in the advanced local stage and in recurrent/metastatic of HNC radiotherapy, could evolve from the “first level” of knowledge (i.e., ballistic precision, dose conformity and homogeneity) to “level two” of “biological dose painting” (in which the concept of tumor heterogeneity and radio-resistance supports the need for doses escalation based on biological criteria), and finally to the “third level“ ofthe new concept of “immunological dose painting”. The peculiarity of this concept is that the radiotherapy target volumes and tumoricidal dose can be completely reevaluated, taking into account the immune-modulatory effect of irradiation. In this case, the tumor target volume can include even the tumor microenvironment or a partial volume of the primary tumor or metastasis, not all the gross and microscopic disease. Tumoricidal biologically equivalent dose (BED) may be completely different from the currently estimated values, radiotherapy treating the tumor in this case indirectly by boosting the immune response. Thus, the clinical target volume (CTV) can be replaced with a new immunological-clinical target volume (ICTV) for patients who benefit from the RT–IT association (Image 1).

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