Abstract
BackgroundThe number of people with implanted hip prosthesis has grown worldwide. For radiotherapy planning of patients with hip implants, few main challenges are encountered. The aim of the present study was to evaluate the feasibility of different planning algorithms in the presence of high-density metallic implant in the treatment of patients with carcinoma cervix.ResultsIt was found that D98% were 44.49 ± 0.11, 44.51 ± 0.13, 44.39 ± 0.22, and 44.45 ± 0.16 Gy for 4FMC6MV (4-field technique calculated with Monte-Carlo algorithm and 6 MV photon energy), 4FMC6MV_WP (4-field technique calculated with Monte-Carlo algorithm and 6 MV photon energy without prosthesis), 4FCC6MV (4-field technique calculated with collapse-cone-convolution algorithm and 6 MV photon energy), and 4FCC6MV_WP (4-field technique calculated with collapse-cone-convolution algorithm and 6 MV photon energy without prosthesis) respectively. Similarly, D2% were 49.40 ± 0.84, 49.05 ± 0.76, 48.97 ± 0.91, and 48.57 ± 0.85 Gray (Gy) for 4FMC6MV, 4FMC6MV_WP, 4FCC6MV, and 4FCC6MV_WP respectively. The present study has not suggested any major difference between the Monte-Carlo (MC) and collapse-cone-convolution (CCC) calculation algorithm in the presence of high-Z metallic implants. Volume of bowel receiving 15 Gy dose has shown a significant difference with prosthesis cases. This study investigates that hip prosthesis creates considerable changes in the treatment planning of cervical malignancies.ConclusionCCC algorithm is in good agreement with MC calculation algorithm in the presence of high-density metallic implants in terms of target coverage and avoidance organ sparing except few parameters.
Highlights
The number of people with implanted hip prosthesis has grown worldwide
The results indicated that treatment plans have similar isodose curves, tumor control probability, normal tissue complication probability, and dose-volume histograms as the MC plan which was calculated with superposition algorithm
Our planning goal was to achieve 98% prescription dose to 100% of planning target volume (PTV) volume, i.e., the PTV should be covered with at least 98% of prescribed dose
Summary
The number of people with implanted hip prosthesis has grown worldwide. For radiotherapy planning of patients with hip implants, few main challenges are encountered. According to report of American Association of Physicist in Medicine Task Group No 63 [1], 1–4% of patients with radiation therapy have prosthesis. These devices are typically made from high atomic number (high-Z) elements (high-Z materials are classified as a material with an atomic number higher than the cortical bone). Hip prostheses are made from cobalt-chromemolybdenum (Co-Cr-Mo) alloy because it is believed to be the strongest balance of mechanical strength and corrosion resistance [2]. Both stainless steel and titanium hip prostheses are available for clinical use
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