Medical physics in radiotherapy for cancer treatment

The first known reference to cancer or cancer-like diseases in man was documented almost 5,000 years ago. Cancerous disease has been documented in all animal species that have been thoroughly studied. The terms cancer, neoplasm, tumour and malignancy are usually used interchangeably. The aetiology of malignancy is multifactorial ranging from diet, lifestyle, genetics, radiation, chemicals etc. The basic modalities of cancer treatment are surgery, radiotherapy and chemotherapy. Since the real answer to a simple and successful cancer treatment still eludes us, the treatment modalities continue to evolve.

Extensive surgeries are on the decline and the era of conservation surgery has begun. Chemotherapy has established its role as a major modality, but its true efficacy is seen only in certain types of cancers. Radiotherapy, on the other hand, found a definite place for itself in the management of almost all cancer, for almost all ages of the disease; and can be combined effectively with the other modalities. Therefore it would not be wrong to state that, radiotherapy remains the key treatment in the management of cancer.

 Cancer is one of the leading causes of death globally and radiotherapy is currently essential in the management of cancer patients either alone or in combination with surgery or chemotherapy or both for cure and palliation. Approximately 60% of all cancer patients received radiotherapy each year as definitive, palliative or adjuvant to surgery or chemotherapy. Radiotherapy aims to deliver the precisely measured dose of radiation for defined tumour volume with minimum damage to surrounding healthy tissues. This results in radiation of tumours, high quality of life, prevention of symptoms including pain, restoring luminal patency with minimum morbidity. 

 Medical physics is the application of physics concepts, theories and methods to medicine or healthcare. In radiation therapy, medical physicists work with physicians, optimise treatment plans, and conduct quality control and verification of the actual medical application working in concert with physicians, clinical radiological technologists, and radiotherapy quality control specialists.

They also contribute to maintaining and improving the quality, safety and cost-effectiveness of healthcare services through patient-oriented activities requiring expert action, involvement or advice regarding the specification, selection, acceptance testing, commissioning, quality assurance/control and optimised clinical use of medical devices and regarding patient risks and protection from associated physical agents (e.g., x-rays, electromagnetic fields, laser light, radionuclides) including the prevention of unintended or accidental exposures.

They confirm the accuracy of the position and doses administered to the patient body, ensuring that they are within the clinically required range and that the treatment is performed as prescribed by the physicians. The medical physicists also engage in medical physics research and development related to radiation therapy.

The writer is the Head of the Department of Oncology, Delta Medical College and Hospital, Bangladesh.



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