A Feasibility Study on Ribs as Anatomical Landmarks for Motion Tracking of Lung and Liver Tumors at External Beam Radiotherapy

Abstract

At external beam radiotherapy for some tumors located at thorax region due to lack of information in gray scale fluoroscopic images tumor position determination is problematic. One of the clinical strategies is to implant clip as internal fiducial marker inside or near tumor to represent tumor position while the contrast of implanted clip is highly observable rather than tumor. As alternative, using natural anatomical landmarks located at thorax region of patient body is proposed to extract tumor position information without implanting clips that is invasive method with possible side effect. Among natural landmarks, ribs of rib-cage structure that result proper visualization at X-ray images may be optimal as representative for tumor motion. In this study, we investigated the existence of possible correlation between ribs as natural anatomical landmarks and various lung and liver tumors located at different sites as challenging issue. A simulation study was performed using data extracted from 4-dimensional extended cardiac-torso anthropomorphic phantom that is able to simulate motion effect of dynamic organs, as well. Several tumor sites with predefined distances originated from chosen ribs at anterior-posterior direction were simulated at 3 upper, middle, and lower parts of chest. Correlation coefficient between ribs and tumors was calculated to investigate the robustness of ribs as anatomical landmarks for tumor motion tracking. Moreover, a consistent correlation model was taken into account to track tumor motion with a rib as best candidate among selected ribs. Final results represent availability of using rib cage as anatomical landmark to track lung and liver tumors in a noninvasive way. Observations of our calculations showed a proper correlation between tumors and ribs while the degree of this correlation is changing depends on tumor site while lung tumors are more varied and complex with less correlation with ribs motion against liver tumors.

A novel method of anatomical landmark selection for rib cage 3D reconstruction from biplanar radiography

“…Efforts have been made to quantify the 3D deformity of the rib cage from medical imaging, for instance with optical methods (Charles, Marcoul, Schaeffer, Canavese, & Diméglio, 2017;Hocquelet et al, 2016), computerized tomography (CT, Aaro & Dahlborn, 1981;Nankali, Torshabi, & Miandoab, 2017) and biplanar radiography (Cheriet, Laporte, Kadoury, Labelle, & Dansereau, 2007;Grenier, Parent, & Cheriet, 2013;Jolivet, Sandoz, Laporte, Mitton, & Skalli, 2010). Radiography has an advantage over CT and optical methods, as it is already performed in the clinical routine of adolescent idiopathic scoliosis (AIS) patients.…”

Biomechanical Morphing for Personalized Fitting of Scoliotic Torso Skeleton Models

“…Many studies tried to reconstruct the rib cage in addition to the spine, following a template-based approach. Nankali et al (2017) used CT scans and Cheriet et al (2007) used two postero-anterior radiographs (the standard at 0° and another one at 20°) and one lateral radiograph. Other methods have focused their effort on reducing the radiation on the patient, and reconstructing the rib cage from biplanar radiographs ( Mitton et al, 2008 ; Jolivet, Sandoz, Laporte, Mitton, Skalli; Seoud et al, 2009 ; Dworzak et al, 2010 ; Grenier et al, 2013 ; Aubert et al, 2016 ).…”

“…Previous works morph only a part of the torso skeleton, such as the spine ( Campbell and Petrella, 2015 ; Humbert et al, 2009 ; D evedzic et al, 2012 ; Gajny et al, 2019 ), or are too slow to be used in clinical settings ( Mitton et al, 2008 ; Seoud et al, 2009 ; Grenier et al, 2013 ). Other works use input data which require considerable radiation, such as CT scans or multiple radiographs ( Cheriet et al, 2007 ; Nankali et al, 2017 ). Additionally, the rest of the rib cage reconstruction methods use EOS radiographs ( Aubert et al, 2016 ; Vergari et al, 2018 ; Jolivet, Sandoz, Laporte, Mitton, Skalli), which are not available in most clinical settings.…”

Investigation of tumor and vessel motion correlation in the liver

“…12 Multiple studies have investigated correlations between the tumor and internal anatomical surrogates in the thoracic and abdominal region. 13,[15][16][17][18][19][20][21] Schlosser et al 21 showed results from healthy volunteers indicating that monitoring motion based on internal features close to a target may be more accurate than an external marker, yet the study fell short of using tumors from patient data. To the best of our knowledge, no studies have been published investigating liver vessels as possible surrogates for tumor motion with patient data.…”