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

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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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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108 Evaluation of the impact of a systematic imaging protocol on remaining unimaged days during fractionated external beam radiotherapy for prostate cancer

Radiotherapy and Oncology ◽

10.1016/s0167-8140(05)80269-5 ◽

2005 ◽

Vol 76 ◽

pp. S32-S33

Author(s):

R. Halperin ◽

R. Rajapakshe ◽

K. Finigan

Keyword(s):

Prostate Cancer ◽

External Beam Radiotherapy ◽

External Beam ◽

Imaging Protocol ◽

The Impact

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A study to evaluate the adequacy of pelvic lymph node coverage in carcinoma cervix patients in Indian population by conventional four field box technique using computerized tomography simulation based pelvic lymph node contouring

International Journal of Research in Medical Sciences ◽

10.18203/2320-6012.ijrms20201348 ◽

2020 ◽

Vol 8 (4) ◽

pp. 1491

Author(s):

Tanmoy Ghosh ◽

Joydeep Basu

Keyword(s):

Lymph Node ◽

Lymph Nodes ◽

External Beam Radiotherapy ◽

Pelvic Lymph Node ◽

Radiotherapy Planning ◽

External Beam ◽

Bony Landmark ◽

Carcinoma Cervix ◽

Simulation Based ◽

Ct Simulation

Background: Traditionally pelvic External Beam Radiotherapy is delivered with four field box technique in carcinoma cervix patients. The primary aim of this prospective observational study is to determine the adequacy of pelvic lymph nodal coverage by conventional Four Field Box Technique with the help of pelvic lymph node contouring by CT simulation.Methods: Between January 2013 and August 2015 sixty patients with biopsy proven Carcinoma Cervix were enrolled in this study. Of these fifty-three patients were available for final analysis. CT simulation based Pelvic lymph node contouring was done for each patient. Then two External Beam Radiotherapy plans were generated, one contoured based and the other based on bony landmark based Four Field Box Technique. The number of patients whose contoured lymph nodes lies partly outside the field borders of the bony landmark-based plan and also its extent was determined. D90 of various groups of pelvic lymph nodes obtained from both the plans were compared using ‘paired sample t - test’.Results: It was seen that with Four Field Box Technique there is inadequate coverage of common iliac lymph nodes in 34/53 patients. The difference between the mean D90 of common iliac lymph nodes in two sets of plans was found to be statistically significant.Conclusions: Pelvic field planning should be individualized. CT simulation-based radiotherapy planning should be done for each individual patient to adequately cover the nodal microscopic disease.

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