A dosimetric comparative study following RTOG and ESTRO contouring guidelines for breast radiation therapy

PURPOSE

To compare the dosimetric parameters considering the Radiation Therapy Oncology Group (RTOG) and European Society for Radiotherapy and Oncology (ESTRO) guidelines for breast cancer radiotherapy. Two radiotherapy techniques, intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT), were considered.

PATIENTS AND METHODS

Twenty-eight patients with left-sided medially-located TanyN2M0 tumors were contoured based on RTOG and ESTRO guidelines. 9-field IMRT, 10-field IMRT, 11-field IMRT, and VMAT treatment plans were applied as radiotherapy (RT) techniques for both contouring sets. The dosimetric parameters of the RT plans were extracted and compared.

RESULTS

Comparing dose-volume histogram (DVH) parameters, equivalent uniform dose (EUD), and normal tissue complication probability (NTCP) of OARs across the contouring guidelines and considering each RT technique showed that the only significant differences were higher Dmax, Dmean, V30, and V45, EUD, and NTCP of the thyroid in all treatment modalities when the RTOG guideline had been adopted. Using the VMAT technique, PTV's EUD and the tumor control probability (TCP) were considerably higher when the ESTRO guideline was adopted. Moreover, the conformity index (CI) of VMAT plans was significantly higher when the ESTRO guideline was used.

CONCLUSION

Unless having higher doses to thyroid when the RTOG guideline was adopted, the doses to other organs-at-risk (OAR) were similar between the two considering guidelines. Moreover, except for higher EUD, TCP, and CI for VMAT when the ESTRO guideline was used, no other significant differences were obtained between dosimetric parameters of target volumes considering the RT techniques and contouring guidelines.

Morphology and electrical properties of multi-walled carbon nanotube/carbon aerogel prepared by using polyacrylonitrile as precursor

MWCNT/PAN aerogel composites were synthesized using the Thermal Induced Phase Separation (TIPS) procedure.

Primary health care and immunisation in Iran

The Primary Health Care (PHC) network of Iran consists of a rural and an urban branch. While the rural branch presently covers a sizeable portion of the rural population, the urban PHC project is in its early stages of implementation. The Expanded Programme on Immunisation (EPI) in Iran, which started as an independent and vertical project in early 1983, is being gradually integrated into the PHC network as the latter expands. Results of the second PHC programme review of Iran shows that immunisation coverage of children has improved appreciably since the first PHC review, especially for BCG which stands at 56.3%. Complete immunisation at first birthday in the rural areas with the PHC services is 44.1%, whereas for urban areas other than Teheran it is 28.1%. While the high coverage in the rural areas is attributed to the 'active' approach and vigilance of the providers of immunisation (i.e. the community health workers and the vaccinators of the mobile teams), the higher coverage in the capital city of Teheran is attributed to the involvement of private paediatricians and the generally higher social, economic, and educational status as well as higher interest of mothers. It is noticed that the results of cluster sampling for determination of immunisation coverage in large metropolitan areas of the developing world must be interpreted with much care. The reason is that in these areas extreme fluctuations in the crude birth rate are common and therefore results tend to over-represent the attributes of the segment of population with lower birth rate. It is also argued that complete immunisation might not be the best indicator for assessing the progress of the immunisation efforts. These and other findings are discussed in detail. are discussed in detail.