I found this wondeful prayer and meditation for during chemo and radiation and I am going to use them. Please use this example as something that might help create your prayer.

Prayer and Meditation:
Begin by blessing your Creator/God and expressing gratitude for all of the gifts in your life. Place your hands on either side of the infusion container and give thanks for the medicine or radiation that you are about to receive.

Ask the Source of All That IS to bless the drug and to give it safely to the cancer cells ONLY, stopping their growth and removing them from your body if they are there. If you do not have any cancer cells left, Ask that the medicine be removed as quickly, comfortably and safely as possible.
See the outcome of the treatment as already accomplished with your total and complete healing and repeat this affirmation three times: "I am healed and whole." Finish with "Glory to God on the Highest, Amen" or whatever prayer closing your faith prescribes.
As the treatment starts, you use the following meditation:
Close your eyes, take a few deep breaths at your own pace and level of comfort. Allow your breath to resume its natural pattern of inhalation leading to exhalation, exhalation to inhalation and begin to relax. As you relax, visualize or touch the medication as golden liquid energy with the same consistency as sweet clover honey.
See this wonderful healing energy entering your body at the port or IV (or in the case of radiation, the area where it is aimed) and travelling to the cancer cells, bypassing all of the healthy, normal cells. Sense the heavenly golden energy as being a source of love; a gift that you are receiving and accepting as you empower your own healing. Maintain this visualization for as long as it is comfortable, and when you are ready to return to normal conscious awareness, repeat your gratitude for the gift of healing and see yourself as healthy and whole. Take a few more deep cleansing breaths at your pace and level of comfort, and when you are ready, open your eyes. Many blessing on your healing path!

very powerful
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I know, isn't it perfect?
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