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

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.

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SU-GG-T-585: The Impact of Free Breathing versus Average 4D CT Image Data on External Beam Radiotherapy Planning for Liver Tumors

Medical Physics ◽

10.1118/1.3468986 ◽

2010 ◽

Vol 37 (6Part25) ◽

pp. 3322-3322

Author(s):

H Li ◽

M Delclos ◽

T Briere ◽

S Beddar ◽

P Das ◽

...

Keyword(s):

Liver Tumors ◽

External Beam Radiotherapy ◽

Image Data ◽

Free Breathing ◽

Radiotherapy Planning ◽

External Beam ◽

Ct Image ◽

4D Ct ◽

The Impact

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Repeat 90Y-microsphere radioembolization for hepatic malignancies: Safety and patient selection issues

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.15177 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 15177-15177

Author(s):

A. S. Kennedy ◽

W. A. Dezarn ◽

P. McNeillie ◽

M. England ◽

C. Overton ◽

...

Keyword(s):

Liver Function ◽

Liver Tumors ◽

External Beam Radiotherapy ◽

Liver Volume ◽

Latency Period ◽

Normal Liver ◽

External Beam Radiation ◽

Unknown Primary ◽

External Beam ◽

Beam Radiation

15177 Background: Liver tolerance to reirradiation with multiple doses of 90Y-microspheres is not known. Many patients (pts) have also received external beam radiotherapy to the liver or through the liver and are surviving long enough to be considered for a second and third liver treatments with internal radiation. Methods: The experience of a single center treating liver tumors with resin 90Y-microspheres was used. Pts that received liver radiation prior to or after resin microsphere therapy were studied. Endpoints were toxicity, tumor response, disease type, latency period between radiation treatments, shunting to lung, and effects on liver volume and function. The delivery activity of microspheres selected was not reduced below that which was typically chosen for patients without prior liver radiation which was 25% reduced from the manufacturer’s BSA dose calculation method. All patients received bilobar microsphere delivery during a single session. Results: A total of 40 pts were identified; 14 women, 26 men, treated 6/2003 to 12/2006, with 35 pts receiving 2 courses and 5 pts with 3 courses of liver radiation. Retreatment with resin microspheres 26 pts, prior external beam radiation in 7 pts, prior glass microspheres in 2pts, prior systemic radiotherapy in 2 pts, and prior stereotactic liver radiation in 1 pt. Liver function was stable and adequate in all patients after additional liver radiation, and no pts developed radiation-induced liver dysfunction (RILD) or veno-occlusive disease (VOD). The percentage of shunting to the lung decreased with retreatment. Tumors treated: 14 carcinoid, 11 colorectal, 6 hepatocellular and cholangiocarcinoma, 2 sarcoma, 3 unknown primary, 1 each of breast, esophagus, and head and neck primaries. Conclusions: Repeated radiation to the liver with 90Y-microspheres appears safe in patients that have sufficient normal liver function and reserve based on known laboratory parameters already used for selection of microsphere therapy. No acute life-threatening, fatal, or late liver damage was observed, i.e. RILD or VOD. No specific dose reduction is recommended for retreatment of the liver. No significant financial relationships to disclose.

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