Thermoplastic fixation of patients undergoing radiotherapy of thoracic region

Đurđica Harmicar, Kemal Choudhury, Helena Režić

KBC Zagreb

Zagreb,7.studeni 2015

Introduction Research was conducted on patients with lung

cancer Lung cancer is the most common in the world More than 3000 people are diagnosed with

lung cancer in Croatia every year Most common types are:

› SCLC› NSCLC

Goals of study Advantages and disadvantages of thermoplastic masks

in radiation therapy of thoracic region

Eficiency of thermoplasctic masks in positioning and fixation of patients during RT treatment of lung carcinoma

The study was conducted on 16 patients

8 patient with masks 8 patient withouth masks

CT simulation was done on Toshiba Aquillion LB CT scanner

RT therapy was done on Elekta Synergy linear accelerator

Positioning and fixation of patients Positioning – head in, supine For positioning was used Blue Orfit set with the same

extensions for both groups

Patient with thermoplastic mask

Referent points are on body and mask

Patients without thermoplastic mask

Referent point on body only

All informations about patients position and extensions used are noted in the Patient chart for future reference

Patient registration

Registration of patents was done:› Before RT tretment› After RT treatment

First 3 fractions and every fifth time during the treatment

All offsets were recorded in chart for the patients

Patient registration tools For patient registration XVI (X-ray Volume Imaging) was

used Protocol on XVI: Chest Volume View with Bowtie filter

F1 – Chest M20 360 degree gantry rotation ~ 5 f/s 2 min / (3.18°/s)

Registration results

Upon completion of RT treatment for each patient, we calculated the mean shift for all three planes

› Sagittal plane› Transverse plane› Coronal plane

Registration results

Obtained data was used in Excel spreadsheet seperately for patients:

› with thermoplastic masks › without thermoplastic masks

Results are compared on the graphs

Registration with thermoplastic fixation

Sagittal (lateral) plane

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

Before treatment

After treatment

Registration with thermoplastic fixation

Transverse (longitudinal) plane

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

Before treatment

After treatment

Registration with thermoplastic fixation

Frontal (coronal) plane

1 2 3 4 5 6 7 80

0.1

0.2

0.3

Before treatment

After treatment

Registration without thermoplastic fixation

Sagittal (lateral) plane

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

Before treatment

After treatment

Registration without thermoplastic fixation

Transverse (longitudinal) plane

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

Before treatment

After treatment

Registration without thermoplastic fixation

Frontal (coronal) plane

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

0.6

Before treatment

After treatment

Crossreference of sagittal (lateral) line

with thermoplastic fixation

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

Before treatment

After treatment

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

Before treatment

After treatment

without thermoplastic fixation

Crossreference of transverse (longitudianl) line

with thermoplastic fixation

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

Before treatment

After treatment

without thermoplastic fixation

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

Before treatmentAfter treatment

Crossreference of frontal (coronal) line

with thermoplastic fixation

without thermoplastic fixation

1 2 3 4 5 6 7 80

0.1

0.2

0.3

Before treatment

After treatment

1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

0.6

Before treatment

After treatment

Advantages of fixation with masks

Minimizes the physical movements of the patient (e.g. Cough)

Possible reconstruction of reference marks Double check the patients position Monitoring of patients weight Possible reconstruction of izocentric marks

Disadvantages of patients with masks

A sense of fear and discomfort for some patients

Longer positioning of patients Higher financial cost of treatment

Conclusion

The use of thermoplastic masks showed that we were a little more precise in positioning of the patients, also it has showen its benefits in other aspects of radiation therapy course.

Thank you for your attention!!!