| ORIGINAL ARTICLE |
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| Year : 2009 | Volume
: 34
| Issue : 1 | Page : 23-30 |
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Dosimetric validation of first helical tomotherapy Hi-Art II machine in India
Rajesh A Kinhikar1, Swamidas V Jamema1, Reenadevi2, Rajeshri Pai2, Master Zubin2, Tejpal Gupta2, Deepak S Dhote3, Deepak D Deshpande1, Shyam K Shrivastava1, Rajiv Sarin2
1 Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai, India
2 Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Kharghar, Navi Mumbai, India
3 Brijlal Biyani Science College, Amravati, India
Correspondence Address:
Rajesh A Kinhikar
Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai - 400 012
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0971-6203.48717
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A Helical Tomotherapy (HT) Hi-Art II machine, Hi ART (TomoTherapy, Inc., Madison, WI, USA) was installed at our center in July 2007, and was the first machine in India. Image-guided HT is a new modality for delivering intensity modulated radiotherapy (IMRT). Dosimetric tests done include (a) primary beam alignment (b) secondary beam alignment (c) water tank measurements (profiles and depth doses) (d) dose rate measurements (e) IMRT verification, and (f) Mega voltage Computed Tomography (MVCT) dose. Primary and secondary beam alignment revealed an acceptable linear accelerator (linac) alignment in both X and Y axes. In addition, it was observed that the beam was aligned in the same plane as gantry and the jaws were not twisted with respect to gantry. The rotational beam stability was acceptable. Multi-leaf collimators (MLC) were found to be stable and properly aligned with the radiation plane. The jaw alignment during gantry rotation was satisfactory. Transverse and longitudinal profiles were in good agreement with the "Gold" standard. During IMRT verification, the variation between the measured and calculated dose for a particular plan at the central and off-axis was found to be within 2% and 1mm in position, respectively. The dose delivered during the TomoImage scan was found to be 2.57 cGy. The Helical Tomotherapy system is mechanically stable and found to be acceptable for clinical treatment. It is recommended that the output of the machine should be measured on a daily basis to monitor the fluctuations in output. |
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