Large-scale dose evaluation of deep learning organ contours in head-and-neck radiotherapy by leveraging existing plans

Background and purpose: Retrospective dose evaluation for organ-at-risk auto-contours has previously used small cohorts due to additional manual effort required for treatment planning on auto-contours. We aimed to do this at large scale, by a) proposing and assessing an automated plan optimization workflow that used existing clinical plan parameters and b) using it for head-and-neck auto-contour dose evaluation. Materials and methods: Our automated workflow emulated our clinic's treatment planning protocol and reused existing clinical plan optimization parameters. This workflow recreated the original clinical plan (POG) with manual contours (PMC) and evaluated the dose effect (POG-PMC) on 70 photon and 30 proton plans of head-and-neck patients. As a use-case, the same workflow (and parameters) created a plan using auto-contours (PAC) of eight head-and-neck organs-at-risk from a commercial tool and evaluated their dose effect (PMC-PAC). Results: For plan recreation (POG-PMC), our workflow had a median impact of 1.0% and 1.5% across dose metrics of auto-contours, for photon and proton respectively. Computer time of automated planning was 25% (photon) and 42% (proton) of manual planning time. For auto-contour evaluation (PMC-PAC), we noticed an impact of 2.0% and 2.6% for photon and proton radiotherapy. All evaluations had a median ΔNTCP (Normal Tissue Complication Probability) less than 0.3%. Conclusions: The plan replication capability of our automated program provides a blueprint for other clinics to perform auto-contour dose evaluation with large patient cohorts. Finally, despite geometric differences, auto-contours had a minimal median dose impact, hence inspiring confidence in their utility and facilitating their clinical adoption.</p

Hyperventilatie is niet specifiek voor paniekpatiënten

Veel onderzoekers hebben gerapporteerd dat paniekpatiënten, tijdens rust een klein beetje hyperventileren; vergeleken met gezonde controleproefpersonen is de CO2–spiegel van paniekpatiënten aan de lage kant. De huidige auteurs gingen na of de lage rust– CO2 diagnostisch specifiek is voor paniekpatiënten. Dat bleek niet zo te zijn. Paniekpatiënten hadden weliswaar een lagere rust–CO2 dan patiënten die geen last hadden van paniekaanvallen en leden aan bijvoorbeeld een dwangneurose of een sociale fobie. De lage rust–CO2 was dus niet specifiek voor paniekpatiënten. Tijdens angst gaan mensen een beetje hyperventileren. De auteurs gingen na of bij paniekpatiënten angst vergezeld gaat met relatief sterk hyperventileren. Ook dit bleek niet het geval te zijn. Paniekpatiënten die enigszins bang werden gingen enigszins hyperventileren, maar andere proefpersonen die een beetje angstig werden vertoonden een vergelijkbare mate van hyperventilatie. De conclusie van de auteurs staat geformuleerd in de titel van deze bijdrage

Hyperventilatie is niet specifiek voor paniekpatiënten

Veel onderzoekers hebben gerapporteerd dat paniekpatiënten, tijdens rust een klein beetje hyperventileren; vergeleken met gezonde controleproefpersonen is de CO2–spiegel van paniekpatiënten aan de lage kant. De huidige auteurs gingen na of de lage rust– CO2 diagnostisch specifiek is voor paniekpatiënten. Dat bleek niet zo te zijn. Paniekpatiënten hadden weliswaar een lagere rust–CO2 dan patiënten die geen last hadden van paniekaanvallen en leden aan bijvoorbeeld een dwangneurose of een sociale fobie. De lage rust–CO2 was dus niet specifiek voor paniekpatiënten. Tijdens angst gaan mensen een beetje hyperventileren. De auteurs gingen na of bij paniekpatiënten angst vergezeld gaat met relatief sterk hyperventileren. Ook dit bleek niet het geval te zijn. Paniekpatiënten die enigszins bang werden gingen enigszins hyperventileren, maar andere proefpersonen die een beetje angstig werden vertoonden een vergelijkbare mate van hyperventilatie. De conclusie van de auteurs staat geformuleerd in de titel van deze bijdrage

The structure of obsessive-compulsive symptoms

In the present study, the structure of obsessive-compulsive symptoms was investigated by means of the Padua Inventory (PI). Simultaneous Components Analysis on data from obsessive-compulsives (n = 206), patients with other anxiety disorders (n = 222), and a non clinical sample (n = 430) revealed a five-factor solution. These factors are: (I) impulses; (II) washing; (III) checking; (IV) rumination; and (V) precision. Forty-one items were selected as measure of these factors. The reliability for the five subscales, assessing each of the five factors, was found to be satisfactory to excellent. Four subscales (washing, checking, rumination and precision) discriminated between panic disorder patients, social phobics and normals on the one hand and obsessive compulsives on the other. The Impulses subscale discriminated between obsessive-compulsives on the one hand and normals on the other, but not between obsessive-compulsives and social phobics or panic patients. Some evidence in support of the construct validity was found. The Padua Inventory-Revised (41-items) appears to measure the structure of obsessive compulsive symptoms: The main types of behaviours and obsessions as seen clinically are assessed by this questionnaire, apart from obsessional slowness

Are prepared fears less severe, but more resistant to treatment?

In order to investigate the relationship between the extent to which clinical fears are prepared and clinically relevant characteristics of these fears (i.e. severity, age of onset and treatment outcome). the records of 63 obsessional and phobic patients were examined. Four independent raters scored the usable records (N = 55) on preparedness. The preparedness scores were combined and related to objective indices of severity (patients' scores on the Fear Survey Schedule, the Zung Depression Scale and the Maudsley Obsessional-Compulsive Inventory, as well as the treatment duration), onset ages and treatment outcomes (pre-treatment minus post-treatment MOCI scores, for a subsample of obsessional patients only). In contrast to earlier studies, it was found that product-moment correlations among preparedness ratings were relatively low and that prepared fears did not make up a majority in the sample. Indices of severity either did not correlate at all or correlated negatively with preparedness ratings. The positive correlation between preparedness and onset ages reached borderline significance. Evidence suggestive of a resistance to treatment of prepared fears was obtained

Large-scale dose evaluation of deep learning organ contours in head-and-neck radiotherapy by leveraging existing plans

Background and purpose: Retrospective dose evaluation for organ-at-risk auto-contours has previously used small cohorts due to additional manual effort required for treatment planning on auto-contours. We aimed to do this at large scale, by a) proposing and assessing an automated plan optimization workflow that used existing clinical plan parameters and b) using it for head-and-neck auto-contour dose evaluation. Materials and methods: Our automated workflow emulated our clinic's treatment planning protocol and reused existing clinical plan optimization parameters. This workflow recreated the original clinical plan (POG) with manual contours (PMC) and evaluated the dose effect (POG-PMC) on 70 photon and 30 proton plans of head-and-neck patients. As a use-case, the same workflow (and parameters) created a plan using auto-contours (PAC) of eight head-and-neck organs-at-risk from a commercial tool and evaluated their dose effect (PMC-PAC). Results: For plan recreation (POG-PMC), our workflow had a median impact of 1.0% and 1.5% across dose metrics of auto-contours, for photon and proton respectively. Computer time of automated planning was 25% (photon) and 42% (proton) of manual planning time. For auto-contour evaluation (PMC-PAC), we noticed an impact of 2.0% and 2.6% for photon and proton radiotherapy. All evaluations had a median ΔNTCP (Normal Tissue Complication Probability) less than 0.3%. Conclusions: The plan replication capability of our automated program provides a blueprint for other clinics to perform auto-contour dose evaluation with large patient cohorts. Finally, despite geometric differences, auto-contours had a minimal median dose impact, hence inspiring confidence in their utility and facilitating their clinical adoption.</p

Development and initial validation of the obsessive beliefs questionnaire and the interpretation of intrusions inventory

In 1995 the Obsessive Compulsive Cognitions Working Group initiated a collective process to develop two measures of cognition relevant to current cognitive-behavioural models of OCD. An earlier report (Behav. Res. Therapy, 35 (1997) 667) describes the original process of defining relevant domains. This article describes the subsequent steps of the development and validation process: item generation, scale reduction, and initial examination of reliability and validity. Two scales were developed. The Obsessive Beliefs Questionnaire consists of 87 items representing dysfunctional assumptions covering six domains: overestimation of threat, tolerance of uncertainty, importance of thoughts, control of thoughts, responsibility, and perfectionism. The Interpretation of Intrusions Inventory consists of 31 items that refer to interpretations of intrusions that have occurred recently. Three of the above domains are represented: importance of thoughts, control of thoughts, and responsibility. The item reduction and validation analyses were conducted on clinical and non-clinical samples from multiple sites. Initial examination of reliability and validity indicates excellent internal consistency and stability and encouraging evidence of validity. However, high correlations indicating overlap between some of the scales, particularly importance of thoughts, control of thoughts, and responsibility will need to be addressed in subsequent empirical and theoretical investigations

Cognitive assessment of obsessive-compulsive disorder

Recent theories of obsessive-compulsive disorder (OCD) emphasize the importance of cognitive contents (beliefs and appraisals) and cognitive processes in the etiology and maintenance of OCD. In order to evaluate these theories and to assess the mechanisms of treatment-related change, it is necessary to develop measures of the relevant cognitive contents and processes. Several scales have been developed, although many are unpublished and there is a great deal of overlap among measures. The purpose of the present article is to describe the progress of an international group of investigators who have commenced a coordinated effort to develop a standardized set of cognitive measures. This article describes the theoretical bases and clinical importance of such an endeavor, and the proceedings of the working group meetings are summarized. Several methods of assessment are reviewed, including idiographic methods, information processing paradigms, and self-report measures. The working group is currently developing and evaluating self-report measures of appraisals about intrusions, and self-report measures of OC-related beliefs. Consensus ratings indicated that 6 belief domains are likely to be important in OCD. These are beliefs pertaining to: (1) inflated responsibility; (2) overimportance of thoughts; (3) excessive concern about the importance of controlling one's thoughts; (4) overestimation of threat; (5) intolerance of uncertainty; and (6) perfectionism